malloc.c source code [glibc/malloc/malloc.c]

1	/ Malloc implementation for multiple threads without lock contention.*
2	Copyright (C) 1996-2019 Free Software Foundation, Inc.
3	This file is part of the GNU C Library.
4	Contributed by Wolfram Gloger <wg@malloc.de>
5	and Doug Lea <dl@cs.oswego.edu>, 2001.
6
7	The GNU C Library is free software; you can redistribute it and/or
8	modify it under the terms of the GNU Lesser General Public License as
9	published by the Free Software Foundation; either version 2.1 of the
10	License, or (at your option) any later version.
11
12	The GNU C Library is distributed in the hope that it will be useful,
13	but WITHOUT ANY WARRANTY; without even the implied warranty of
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15	Lesser General Public License for more details.
16
17	You should have received a copy of the GNU Lesser General Public
18	License along with the GNU C Library; see the file COPYING.LIB. If
19	not, see <http://www.gnu.org/licenses/>. /*
20
21	/*
22	This is a version (aka ptmalloc2) of malloc/free/realloc written by
23	Doug Lea and adapted to multiple threads/arenas by Wolfram Gloger.
24
25	There have been substantial changes made after the integration into
26	glibc in all parts of the code. Do not look for much commonality
27	with the ptmalloc2 version.
28
29	* Version ptmalloc2-20011215
30	based on:
31	VERSION 2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
32
33	* Quickstart
34
35	In order to compile this implementation, a Makefile is provided with
36	the ptmalloc2 distribution, which has pre-defined targets for some
37	popular systems (e.g. "make posix" for Posix threads). All that is
38	typically required with regard to compiler flags is the selection of
39	the thread package via defining one out of USE_PTHREADS, USE_THR or
40	USE_SPROC. Check the thread-m.h file for what effects this has.
41	Many/most systems will additionally require USE_TSD_DATA_HACK to be
42	defined, so this is the default for "make posix".
43
44	* Why use this malloc?
45
46	This is not the fastest, most space-conserving, most portable, or
47	most tunable malloc ever written. However it is among the fastest
48	while also being among the most space-conserving, portable and tunable.
49	Consistent balance across these factors results in a good general-purpose
50	allocator for malloc-intensive programs.
51
52	The main properties of the algorithms are:
53	* For large (>= 512 bytes) requests, it is a pure best-fit allocator,
54	with ties normally decided via FIFO (i.e. least recently used).
55	* For small (<= 64 bytes by default) requests, it is a caching
56	allocator, that maintains pools of quickly recycled chunks.
57	* In between, and for combinations of large and small requests, it does
58	the best it can trying to meet both goals at once.
59	* For very large requests (>= 128KB by default), it relies on system
60	memory mapping facilities, if supported.
61
62	For a longer but slightly out of date high-level description, see
63	http://gee.cs.oswego.edu/dl/html/malloc.html
64
65	You may already by default be using a C library containing a malloc
66	that is based on some version of this malloc (for example in
67	linux). You might still want to use the one in this file in order to
68	customize settings or to avoid overheads associated with library
69	versions.
70
71	* Contents, described in more detail in "description of public routines" below.
72
73	Standard (ANSI/SVID/...) functions:
74	malloc(size_t n);
75	calloc(size_t n_elements, size_t element_size);
76	free(void p);*
77	realloc(void p, size_t n);*
78	memalign(size_t alignment, size_t n);
79	valloc(size_t n);
80	mallinfo()
81	mallopt(int parameter_number, int parameter_value)
82
83	Additional functions:
84	independent_calloc(size_t n_elements, size_t size, void chunks[]);*
85	independent_comalloc(size_t n_elements, size_t sizes[], void chunks[]);*
86	pvalloc(size_t n);
87	malloc_trim(size_t pad);
88	malloc_usable_size(void p);*
89	malloc_stats();
90
91	* Vital statistics:
92
93	Supported pointer representation: 4 or 8 bytes
94	Supported size_t representation: 4 or 8 bytes
95	Note that size_t is allowed to be 4 bytes even if pointers are 8.
96	You can adjust this by defining INTERNAL_SIZE_T
97
98	Alignment: 2 sizeof(size_t) (default)*
99	(i.e., 8 byte alignment with 4byte size_t). This suffices for
100	nearly all current machines and C compilers. However, you can
101	define MALLOC_ALIGNMENT to be wider than this if necessary.
102
103	Minimum overhead per allocated chunk: 4 or 8 bytes
104	Each malloced chunk has a hidden word of overhead holding size
105	and status information.
106
107	Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
108	8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
109
110	When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
111	ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
112	needed; 4 (8) for a trailing size field and 8 (16) bytes for
113	free list pointers. Thus, the minimum allocatable size is
114	16/24/32 bytes.
115
116	Even a request for zero bytes (i.e., malloc(0)) returns a
117	pointer to something of the minimum allocatable size.
118
119	The maximum overhead wastage (i.e., number of extra bytes
120	allocated than were requested in malloc) is less than or equal
121	to the minimum size, except for requests >= mmap_threshold that
122	are serviced via mmap(), where the worst case wastage is 2 *
123	sizeof(size_t) bytes plus the remainder from a system page (the
124	minimal mmap unit); typically 4096 or 8192 bytes.
125
126	Maximum allocated size: 4-byte size_t: 2^32 minus about two pages
127	8-byte size_t: 2^64 minus about two pages
128
129	It is assumed that (possibly signed) size_t values suffice to
130	represent chunk sizes. `Possibly signed' is due to the fact
131	that `size_t' may be defined on a system as either a signed or
132	an unsigned type. The ISO C standard says that it must be
133	unsigned, but a few systems are known not to adhere to this.
134	Additionally, even when size_t is unsigned, sbrk (which is by
135	default used to obtain memory from system) accepts signed
136	arguments, and may not be able to handle size_t-wide arguments
137	with negative sign bit. Generally, values that would
138	appear as negative after accounting for overhead and alignment
139	are supported only via mmap(), which does not have this
140	limitation.
141
142	Requests for sizes outside the allowed range will perform an optional
143	failure action and then return null. (Requests may also
144	also fail because a system is out of memory.)
145
146	Thread-safety: thread-safe
147
148	Compliance: I believe it is compliant with the 1997 Single Unix Specification
149	Also SVID/XPG, ANSI C, and probably others as well.
150
151	* Synopsis of compile-time options:
152
153	People have reported using previous versions of this malloc on all
154	versions of Unix, sometimes by tweaking some of the defines
155	below. It has been tested most extensively on Solaris and Linux.
156	People also report using it in stand-alone embedded systems.
157
158	The implementation is in straight, hand-tuned ANSI C. It is not
159	at all modular. (Sorry!) It uses a lot of macros. To be at all
160	usable, this code should be compiled using an optimizing compiler
161	(for example gcc -O3) that can simplify expressions and control
162	paths. (FAQ: some macros import variables as arguments rather than
163	declare locals because people reported that some debuggers
164	otherwise get confused.)
165
166	OPTION DEFAULT VALUE
167
168	Compilation Environment options:
169
170	HAVE_MREMAP 0
171
172	Changing default word sizes:
173
174	INTERNAL_SIZE_T size_t
175
176	Configuration and functionality options:
177
178	USE_PUBLIC_MALLOC_WRAPPERS NOT defined
179	USE_MALLOC_LOCK NOT defined
180	MALLOC_DEBUG NOT defined
181	REALLOC_ZERO_BYTES_FREES 1
182	TRIM_FASTBINS 0
183
184	Options for customizing MORECORE:
185
186	MORECORE sbrk
187	MORECORE_FAILURE -1
188	MORECORE_CONTIGUOUS 1
189	MORECORE_CANNOT_TRIM NOT defined
190	MORECORE_CLEARS 1
191	MMAP_AS_MORECORE_SIZE (1024 1024)*
192
193	Tuning options that are also dynamically changeable via mallopt:
194
195	DEFAULT_MXFAST 64 (for 32bit), 128 (for 64bit)
196	DEFAULT_TRIM_THRESHOLD 128 1024*
197	DEFAULT_TOP_PAD 0
198	DEFAULT_MMAP_THRESHOLD 128 1024*
199	DEFAULT_MMAP_MAX 65536
200
201	There are several other #defined constants and macros that you
202	probably don't want to touch unless you are extending or adapting malloc. /*
203
204	/*
205	void is the pointer type that malloc should say it returns*
206	*/
207
208	#ifndef void
209	#define void void
210	#endif /void/
211
212	#include <stddef.h> /* for size_t */
213	#include <stdlib.h> /* for getenv(), abort() */
214	#include <unistd.h> /* for __libc_enable_secure */
215
216	#include <atomic.h>
217	#include <_itoa.h>
218	#include <bits/wordsize.h>
219	#include <sys/sysinfo.h>
220
221	#include <ldsodefs.h>
222
223	#include <unistd.h>
224	#include <stdio.h> /* needed for malloc_stats */
225	#include <errno.h>
226	#include <assert.h>
227
228	#include <shlib-compat.h>
229
230	/ For uintptr_t. /
231	#include <stdint.h>
232
233	/ For va_arg, va_start, va_end. /
234	#include <stdarg.h>
235
236	/ For MIN, MAX, powerof2. /
237	#include <sys/param.h>
238
239	/ For ALIGN_UP et. al. /
240	#include <libc-pointer-arith.h>
241
242	/ For DIAG_PUSH/POP_NEEDS_COMMENT et al. /
243	#include <libc-diag.h>
244
245	#include <malloc/malloc-internal.h>
246
247	/ For SINGLE_THREAD_P. /
248	#include <sysdep-cancel.h>
249
250	/*
251	Debugging:
252
253	Because freed chunks may be overwritten with bookkeeping fields, this
254	malloc will often die when freed memory is overwritten by user
255	programs. This can be very effective (albeit in an annoying way)
256	in helping track down dangling pointers.
257
258	If you compile with -DMALLOC_DEBUG, a number of assertion checks are
259	enabled that will catch more memory errors. You probably won't be
260	able to make much sense of the actual assertion errors, but they
261	should help you locate incorrectly overwritten memory. The checking
262	is fairly extensive, and will slow down execution
263	noticeably. Calling malloc_stats or mallinfo with MALLOC_DEBUG set
264	will attempt to check every non-mmapped allocated and free chunk in
265	the course of computing the summmaries. (By nature, mmapped regions
266	cannot be checked very much automatically.)
267
268	Setting MALLOC_DEBUG may also be helpful if you are trying to modify
269	this code. The assertions in the check routines spell out in more
270	detail the assumptions and invariants underlying the algorithms.
271
272	Setting MALLOC_DEBUG does NOT provide an automated mechanism for
273	checking that all accesses to malloced memory stay within their
274	bounds. However, there are several add-ons and adaptations of this
275	or other mallocs available that do this.
276	*/
277
278	#ifndef MALLOC_DEBUG
279	#define MALLOC_DEBUG 0
280	#endif
281
282	#ifndef NDEBUG
283	# define __assert_fail(assertion, file, line, function) \
284	__malloc_assert(assertion, file, line, function)
285
286	extern const char *__progname;
287
288	static void
289	__malloc_assert (const char assertion, const* char file, unsigned* int line,
290	const char *function)
291	{
292	(void) __fxprintf (NULL, "%s%s%s:%u: %s%sAssertion `%s' failed.\n",
293	__progname, __progname[`0`] ? ": " : "",
294	file, line,
295	function ? function : "", function ? ": " : "",
296	assertion);
297	fflush (stderr);
298	abort ();
299	}
300	#endif
301
302	#if USE_TCACHE
303	/ We want 64 entries. This is an arbitrary limit, which tunables can reduce. /
304	# define TCACHE_MAX_BINS 64
305	# define MAX_TCACHE_SIZE tidx2usize (TCACHE_MAX_BINS-1)
306
307	/ Only used to pre-fill the tunables. /
308	# define tidx2usize(idx) (((size_t) idx) * MALLOC_ALIGNMENT + MINSIZE - SIZE_SZ)
309
310	/ When "x" is from chunksize(). /
311	# define csize2tidx(x) (((x) - MINSIZE + MALLOC_ALIGNMENT - 1) / MALLOC_ALIGNMENT)
312	/ When "x" is a user-provided size. /
313	# define usize2tidx(x) csize2tidx (request2size (x))
314
315	/ With rounding and alignment, the bins are...*
316	idx 0 bytes 0..24 (64-bit) or 0..12 (32-bit)
317	idx 1 bytes 25..40 or 13..20
318	idx 2 bytes 41..56 or 21..28
319	etc. /*
320
321	/ This is another arbitrary limit, which tunables can change. Each*
322	tcache bin will hold at most this number of chunks. /*
323	# define TCACHE_FILL_COUNT 7
324	#endif
325
326
327	/*
328	REALLOC_ZERO_BYTES_FREES should be set if a call to
329	realloc with zero bytes should be the same as a call to free.
330	This is required by the C standard. Otherwise, since this malloc
331	returns a unique pointer for malloc(0), so does realloc(p, 0).
332	*/
333
334	#ifndef REALLOC_ZERO_BYTES_FREES
335	#define REALLOC_ZERO_BYTES_FREES 1
336	#endif
337
338	/*
339	TRIM_FASTBINS controls whether free() of a very small chunk can
340	immediately lead to trimming. Setting to true (1) can reduce memory
341	footprint, but will almost always slow down programs that use a lot
342	of small chunks.
343
344	Define this only if you are willing to give up some speed to more
345	aggressively reduce system-level memory footprint when releasing
346	memory in programs that use many small chunks. You can get
347	essentially the same effect by setting MXFAST to 0, but this can
348	lead to even greater slowdowns in programs using many small chunks.
349	TRIM_FASTBINS is an in-between compile-time option, that disables
350	only those chunks bordering topmost memory from being placed in
351	fastbins.
352	*/
353
354	#ifndef TRIM_FASTBINS
355	#define TRIM_FASTBINS 0
356	#endif
357
358
359	/ Definition for getting more memory from the OS. /
360	#define MORECORE (*__morecore)
361	#define MORECORE_FAILURE 0
362	void * __default_morecore (ptrdiff_t);
363	void (__morecore)(ptrdiff_t) = __default_morecore;
364
365
366	#include <string.h>
367
368	/*
369	MORECORE-related declarations. By default, rely on sbrk
370	*/
371
372
373	/*
374	MORECORE is the name of the routine to call to obtain more memory
375	from the system. See below for general guidance on writing
376	alternative MORECORE functions, as well as a version for WIN32 and a
377	sample version for pre-OSX macos.
378	*/
379
380	#ifndef MORECORE
381	#define MORECORE sbrk
382	#endif
383
384	/*
385	MORECORE_FAILURE is the value returned upon failure of MORECORE
386	as well as mmap. Since it cannot be an otherwise valid memory address,
387	and must reflect values of standard sys calls, you probably ought not
388	try to redefine it.
389	*/
390
391	#ifndef MORECORE_FAILURE
392	#define MORECORE_FAILURE (-1)
393	#endif
394
395	/*
396	If MORECORE_CONTIGUOUS is true, take advantage of fact that
397	consecutive calls to MORECORE with positive arguments always return
398	contiguous increasing addresses. This is true of unix sbrk. Even
399	if not defined, when regions happen to be contiguous, malloc will
400	permit allocations spanning regions obtained from different
401	calls. But defining this when applicable enables some stronger
402	consistency checks and space efficiencies.
403	*/
404
405	#ifndef MORECORE_CONTIGUOUS
406	#define MORECORE_CONTIGUOUS 1
407	#endif
408
409	/*
410	Define MORECORE_CANNOT_TRIM if your version of MORECORE
411	cannot release space back to the system when given negative
412	arguments. This is generally necessary only if you are using
413	a hand-crafted MORECORE function that cannot handle negative arguments.
414	*/
415
416	/ #define MORECORE_CANNOT_TRIM /
417
418	/ MORECORE_CLEARS (default 1)*
419	The degree to which the routine mapped to MORECORE zeroes out
420	memory: never (0), only for newly allocated space (1) or always
421	(2). The distinction between (1) and (2) is necessary because on
422	some systems, if the application first decrements and then
423	increments the break value, the contents of the reallocated space
424	are unspecified.
425	*/
426
427	#ifndef MORECORE_CLEARS
428	# define MORECORE_CLEARS 1
429	#endif
430
431
432	/*
433	MMAP_AS_MORECORE_SIZE is the minimum mmap size argument to use if
434	sbrk fails, and mmap is used as a backup. The value must be a
435	multiple of page size. This backup strategy generally applies only
436	when systems have "holes" in address space, so sbrk cannot perform
437	contiguous expansion, but there is still space available on system.
438	On systems for which this is known to be useful (i.e. most linux
439	kernels), this occurs only when programs allocate huge amounts of
440	memory. Between this, and the fact that mmap regions tend to be
441	limited, the size should be large, to avoid too many mmap calls and
442	thus avoid running out of kernel resources. /*
443
444	#ifndef MMAP_AS_MORECORE_SIZE
445	#define MMAP_AS_MORECORE_SIZE (1024 * 1024)
446	#endif
447
448	/*
449	Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
450	large blocks.
451	*/
452
453	#ifndef HAVE_MREMAP
454	#define HAVE_MREMAP 0
455	#endif
456
457	/ We may need to support __malloc_initialize_hook for backwards*
458	compatibility. /*
459
460	#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_24)
461	# define HAVE_MALLOC_INIT_HOOK 1
462	#else
463	# define HAVE_MALLOC_INIT_HOOK 0
464	#endif
465
466
467	/*
468	This version of malloc supports the standard SVID/XPG mallinfo
469	routine that returns a struct containing usage properties and
470	statistics. It should work on any SVID/XPG compliant system that has
471	a /usr/include/malloc.h defining struct mallinfo. (If you'd like to
472	install such a thing yourself, cut out the preliminary declarations
473	as described above and below and save them in a malloc.h file. But
474	there's no compelling reason to bother to do this.)
475
476	The main declaration needed is the mallinfo struct that is returned
477	(by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a
478	bunch of fields that are not even meaningful in this version of
479	malloc. These fields are are instead filled by mallinfo() with
480	other numbers that might be of interest.
481	*/
482
483
484	/ ---------- description of public routines ------------ /
485
486	/*
487	malloc(size_t n)
488	Returns a pointer to a newly allocated chunk of at least n bytes, or null
489	if no space is available. Additionally, on failure, errno is
490	set to ENOMEM on ANSI C systems.
491
492	If n is zero, malloc returns a minumum-sized chunk. (The minimum
493	size is 16 bytes on most 32bit systems, and 24 or 32 bytes on 64bit
494	systems.) On most systems, size_t is an unsigned type, so calls
495	with negative arguments are interpreted as requests for huge amounts
496	of space, which will often fail. The maximum supported value of n
497	differs across systems, but is in all cases less than the maximum
498	representable value of a size_t.
499	*/
500	void* __libc_malloc(size_t);
501	libc_hidden_proto (__libc_malloc)
502
503	/*
504	free(void p)*
505	Releases the chunk of memory pointed to by p, that had been previously
506	allocated using malloc or a related routine such as realloc.
507	It has no effect if p is null. It can have arbitrary (i.e., bad!)
508	effects if p has already been freed.
509
510	Unless disabled (using mallopt), freeing very large spaces will
511	when possible, automatically trigger operations that give
512	back unused memory to the system, thus reducing program footprint.
513	*/
514	void __libc_free(void*);
515	libc_hidden_proto (__libc_free)
516
517	/*
518	calloc(size_t n_elements, size_t element_size);
519	Returns a pointer to n_elements element_size bytes, with all locations*
520	set to zero.
521	*/
522	void* __libc_calloc(size_t, size_t);
523
524	/*
525	realloc(void p, size_t n)*
526	Returns a pointer to a chunk of size n that contains the same data
527	as does chunk p up to the minimum of (n, p's size) bytes, or null
528	if no space is available.
529
530	The returned pointer may or may not be the same as p. The algorithm
531	prefers extending p when possible, otherwise it employs the
532	equivalent of a malloc-copy-free sequence.
533
534	If p is null, realloc is equivalent to malloc.
535
536	If space is not available, realloc returns null, errno is set (if on
537	ANSI) and p is NOT freed.
538
539	if n is for fewer bytes than already held by p, the newly unused
540	space is lopped off and freed if possible. Unless the #define
541	REALLOC_ZERO_BYTES_FREES is set, realloc with a size argument of
542	zero (re)allocates a minimum-sized chunk.
543
544	Large chunks that were internally obtained via mmap will always be
545	grown using malloc-copy-free sequences unless the system supports
546	MREMAP (currently only linux).
547
548	The old unix realloc convention of allowing the last-free'd chunk
549	to be used as an argument to realloc is not supported.
550	*/
551	void* __libc_realloc(void*, size_t);
552	libc_hidden_proto (__libc_realloc)
553
554	/*
555	memalign(size_t alignment, size_t n);
556	Returns a pointer to a newly allocated chunk of n bytes, aligned
557	in accord with the alignment argument.
558
559	The alignment argument should be a power of two. If the argument is
560	not a power of two, the nearest greater power is used.
561	8-byte alignment is guaranteed by normal malloc calls, so don't
562	bother calling memalign with an argument of 8 or less.
563
564	Overreliance on memalign is a sure way to fragment space.
565	*/
566	void* __libc_memalign(size_t, size_t);
567	libc_hidden_proto (__libc_memalign)
568
569	/*
570	valloc(size_t n);
571	Equivalent to memalign(pagesize, n), where pagesize is the page
572	size of the system. If the pagesize is unknown, 4096 is used.
573	*/
574	void* __libc_valloc(size_t);
575
576
577
578	/*
579	mallopt(int parameter_number, int parameter_value)
580	Sets tunable parameters The format is to provide a
581	(parameter-number, parameter-value) pair. mallopt then sets the
582	corresponding parameter to the argument value if it can (i.e., so
583	long as the value is meaningful), and returns 1 if successful else
584	0. SVID/XPG/ANSI defines four standard param numbers for mallopt,
585	normally defined in malloc.h. Only one of these (M_MXFAST) is used
586	in this malloc. The others (M_NLBLKS, M_GRAIN, M_KEEP) don't apply,
587	so setting them has no effect. But this malloc also supports four
588	other options in mallopt. See below for details. Briefly, supported
589	parameters are as follows (listed defaults are for "typical"
590	configurations).
591
592	Symbol param # default allowed param values
593	M_MXFAST 1 64 0-80 (0 disables fastbins)
594	M_TRIM_THRESHOLD -1 1281024 any (-1U disables trimming)*
595	M_TOP_PAD -2 0 any
596	M_MMAP_THRESHOLD -3 1281024 any (or 0 if no MMAP support)*
597	M_MMAP_MAX -4 65536 any (0 disables use of mmap)
598	*/
599	int __libc_mallopt(int, int);
600	libc_hidden_proto (__libc_mallopt)
601
602
603	/*
604	mallinfo()
605	Returns (by copy) a struct containing various summary statistics:
606
607	arena: current total non-mmapped bytes allocated from system
608	ordblks: the number of free chunks
609	smblks: the number of fastbin blocks (i.e., small chunks that
610	have been freed but not use resused or consolidated)
611	hblks: current number of mmapped regions
612	hblkhd: total bytes held in mmapped regions
613	usmblks: always 0
614	fsmblks: total bytes held in fastbin blocks
615	uordblks: current total allocated space (normal or mmapped)
616	fordblks: total free space
617	keepcost: the maximum number of bytes that could ideally be released
618	back to system via malloc_trim. ("ideally" means that
619	it ignores page restrictions etc.)
620
621	Because these fields are ints, but internal bookkeeping may
622	be kept as longs, the reported values may wrap around zero and
623	thus be inaccurate.
624	*/
625	struct mallinfo __libc_mallinfo(void);
626
627
628	/*
629	pvalloc(size_t n);
630	Equivalent to valloc(minimum-page-that-holds(n)), that is,
631	round up n to nearest pagesize.
632	*/
633	void* __libc_pvalloc(size_t);
634
635	/*
636	malloc_trim(size_t pad);
637
638	If possible, gives memory back to the system (via negative
639	arguments to sbrk) if there is unused memory at the `high' end of
640	the malloc pool. You can call this after freeing large blocks of
641	memory to potentially reduce the system-level memory requirements
642	of a program. However, it cannot guarantee to reduce memory. Under
643	some allocation patterns, some large free blocks of memory will be
644	locked between two used chunks, so they cannot be given back to
645	the system.
646
647	The `pad' argument to malloc_trim represents the amount of free
648	trailing space to leave untrimmed. If this argument is zero,
649	only the minimum amount of memory to maintain internal data
650	structures will be left (one page or less). Non-zero arguments
651	can be supplied to maintain enough trailing space to service
652	future expected allocations without having to re-obtain memory
653	from the system.
654
655	Malloc_trim returns 1 if it actually released any memory, else 0.
656	On systems that do not support "negative sbrks", it will always
657	return 0.
658	*/
659	int __malloc_trim(size_t);
660
661	/*
662	malloc_usable_size(void p);*
663
664	Returns the number of bytes you can actually use in
665	an allocated chunk, which may be more than you requested (although
666	often not) due to alignment and minimum size constraints.
667	You can use this many bytes without worrying about
668	overwriting other allocated objects. This is not a particularly great
669	programming practice. malloc_usable_size can be more useful in
670	debugging and assertions, for example:
671
672	p = malloc(n);
673	assert(malloc_usable_size(p) >= 256);
674
675	*/
676	size_t __malloc_usable_size(void*);
677
678	/*
679	malloc_stats();
680	Prints on stderr the amount of space obtained from the system (both
681	via sbrk and mmap), the maximum amount (which may be more than
682	current if malloc_trim and/or munmap got called), and the current
683	number of bytes allocated via malloc (or realloc, etc) but not yet
684	freed. Note that this is the number of bytes allocated, not the
685	number requested. It will be larger than the number requested
686	because of alignment and bookkeeping overhead. Because it includes
687	alignment wastage as being in use, this figure may be greater than
688	zero even when no user-level chunks are allocated.
689
690	The reported current and maximum system memory can be inaccurate if
691	a program makes other calls to system memory allocation functions
692	(normally sbrk) outside of malloc.
693
694	malloc_stats prints only the most commonly interesting statistics.
695	More information can be obtained by calling mallinfo.
696
697	*/
698	void __malloc_stats(void);
699
700	/*
701	posix_memalign(void memptr, size_t alignment, size_t size);
702
703	POSIX wrapper like memalign(), checking for validity of size.
704	*/
705	int __posix_memalign(void **, size_t, size_t);
706
707	/ mallopt tuning options /
708
709	/*
710	M_MXFAST is the maximum request size used for "fastbins", special bins
711	that hold returned chunks without consolidating their spaces. This
712	enables future requests for chunks of the same size to be handled
713	very quickly, but can increase fragmentation, and thus increase the
714	overall memory footprint of a program.
715
716	This malloc manages fastbins very conservatively yet still
717	efficiently, so fragmentation is rarely a problem for values less
718	than or equal to the default. The maximum supported value of MXFAST
719	is 80. You wouldn't want it any higher than this anyway. Fastbins
720	are designed especially for use with many small structs, objects or
721	strings -- the default handles structs/objects/arrays with sizes up
722	to 8 4byte fields, or small strings representing words, tokens,
723	etc. Using fastbins for larger objects normally worsens
724	fragmentation without improving speed.
725
726	M_MXFAST is set in REQUEST size units. It is internally used in
727	chunksize units, which adds padding and alignment. You can reduce
728	M_MXFAST to 0 to disable all use of fastbins. This causes the malloc
729	algorithm to be a closer approximation of fifo-best-fit in all cases,
730	not just for larger requests, but will generally cause it to be
731	slower.
732	*/
733
734
735	/ M_MXFAST is a standard SVID/XPG tuning option, usually listed in malloc.h /
736	#ifndef M_MXFAST
737	#define M_MXFAST 1
738	#endif
739
740	#ifndef DEFAULT_MXFAST
741	#define DEFAULT_MXFAST (64 * SIZE_SZ / 4)
742	#endif
743
744
745	/*
746	M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
747	to keep before releasing via malloc_trim in free().
748
749	Automatic trimming is mainly useful in long-lived programs.
750	Because trimming via sbrk can be slow on some systems, and can
751	sometimes be wasteful (in cases where programs immediately
752	afterward allocate more large chunks) the value should be high
753	enough so that your overall system performance would improve by
754	releasing this much memory.
755
756	The trim threshold and the mmap control parameters (see below)
757	can be traded off with one another. Trimming and mmapping are
758	two different ways of releasing unused memory back to the
759	system. Between these two, it is often possible to keep
760	system-level demands of a long-lived program down to a bare
761	minimum. For example, in one test suite of sessions measuring
762	the XF86 X server on Linux, using a trim threshold of 128K and a
763	mmap threshold of 192K led to near-minimal long term resource
764	consumption.
765
766	If you are using this malloc in a long-lived program, it should
767	pay to experiment with these values. As a rough guide, you
768	might set to a value close to the average size of a process
769	(program) running on your system. Releasing this much memory
770	would allow such a process to run in memory. Generally, it's
771	worth it to tune for trimming rather tham memory mapping when a
772	program undergoes phases where several large chunks are
773	allocated and released in ways that can reuse each other's
774	storage, perhaps mixed with phases where there are no such
775	chunks at all. And in well-behaved long-lived programs,
776	controlling release of large blocks via trimming versus mapping
777	is usually faster.
778
779	However, in most programs, these parameters serve mainly as
780	protection against the system-level effects of carrying around
781	massive amounts of unneeded memory. Since frequent calls to
782	sbrk, mmap, and munmap otherwise degrade performance, the default
783	parameters are set to relatively high values that serve only as
784	safeguards.
785
786	The trim value It must be greater than page size to have any useful
787	effect. To disable trimming completely, you can set to
788	(unsigned long)(-1)
789
790	Trim settings interact with fastbin (MXFAST) settings: Unless
791	TRIM_FASTBINS is defined, automatic trimming never takes place upon
792	freeing a chunk with size less than or equal to MXFAST. Trimming is
793	instead delayed until subsequent freeing of larger chunks. However,
794	you can still force an attempted trim by calling malloc_trim.
795
796	Also, trimming is not generally possible in cases where
797	the main arena is obtained via mmap.
798
799	Note that the trick some people use of mallocing a huge space and
800	then freeing it at program startup, in an attempt to reserve system
801	memory, doesn't have the intended effect under automatic trimming,
802	since that memory will immediately be returned to the system.
803	*/
804
805	#define M_TRIM_THRESHOLD -1
806
807	#ifndef DEFAULT_TRIM_THRESHOLD
808	#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
809	#endif
810
811	/*
812	M_TOP_PAD is the amount of extra `padding' space to allocate or
813	retain whenever sbrk is called. It is used in two ways internally:
814
815	* When sbrk is called to extend the top of the arena to satisfy
816	a new malloc request, this much padding is added to the sbrk
817	request.
818
819	* When malloc_trim is called automatically from free(),
820	it is used as the `pad' argument.
821
822	In both cases, the actual amount of padding is rounded
823	so that the end of the arena is always a system page boundary.
824
825	The main reason for using padding is to avoid calling sbrk so
826	often. Having even a small pad greatly reduces the likelihood
827	that nearly every malloc request during program start-up (or
828	after trimming) will invoke sbrk, which needlessly wastes
829	time.
830
831	Automatic rounding-up to page-size units is normally sufficient
832	to avoid measurable overhead, so the default is 0. However, in
833	systems where sbrk is relatively slow, it can pay to increase
834	this value, at the expense of carrying around more memory than
835	the program needs.
836	*/
837
838	#define M_TOP_PAD -2
839
840	#ifndef DEFAULT_TOP_PAD
841	#define DEFAULT_TOP_PAD (0)
842	#endif
843
844	/*
845	MMAP_THRESHOLD_MAX and _MIN are the bounds on the dynamically
846	adjusted MMAP_THRESHOLD.
847	*/
848
849	#ifndef DEFAULT_MMAP_THRESHOLD_MIN
850	#define DEFAULT_MMAP_THRESHOLD_MIN (128 * 1024)
851	#endif
852
853	#ifndef DEFAULT_MMAP_THRESHOLD_MAX
854	/ For 32-bit platforms we cannot increase the maximum mmap*
855	threshold much because it is also the minimum value for the
856	maximum heap size and its alignment. Going above 512k (i.e., 1M
857	for new heaps) wastes too much address space. /*
858	# if __WORDSIZE == 32
859	# define DEFAULT_MMAP_THRESHOLD_MAX (512 * 1024)
860	# else
861	# define DEFAULT_MMAP_THRESHOLD_MAX (4 * 1024 * 1024 * sizeof(long))
862	# endif
863	#endif
864
865	/*
866	M_MMAP_THRESHOLD is the request size threshold for using mmap()
867	to service a request. Requests of at least this size that cannot
868	be allocated using already-existing space will be serviced via mmap.
869	(If enough normal freed space already exists it is used instead.)
870
871	Using mmap segregates relatively large chunks of memory so that
872	they can be individually obtained and released from the host
873	system. A request serviced through mmap is never reused by any
874	other request (at least not directly; the system may just so
875	happen to remap successive requests to the same locations).
876
877	Segregating space in this way has the benefits that:
878
879	1. Mmapped space can ALWAYS be individually released back
880	to the system, which helps keep the system level memory
881	demands of a long-lived program low.
882	2. Mapped memory can never become `locked' between
883	other chunks, as can happen with normally allocated chunks, which
884	means that even trimming via malloc_trim would not release them.
885	3. On some systems with "holes" in address spaces, mmap can obtain
886	memory that sbrk cannot.
887
888	However, it has the disadvantages that:
889
890	1. The space cannot be reclaimed, consolidated, and then
891	used to service later requests, as happens with normal chunks.
892	2. It can lead to more wastage because of mmap page alignment
893	requirements
894	3. It causes malloc performance to be more dependent on host
895	system memory management support routines which may vary in
896	implementation quality and may impose arbitrary
897	limitations. Generally, servicing a request via normal
898	malloc steps is faster than going through a system's mmap.
899
900	The advantages of mmap nearly always outweigh disadvantages for
901	"large" chunks, but the value of "large" varies across systems. The
902	default is an empirically derived value that works well in most
903	systems.
904
905
906	Update in 2006:
907	The above was written in 2001. Since then the world has changed a lot.
908	Memory got bigger. Applications got bigger. The virtual address space
909	layout in 32 bit linux changed.
910
911	In the new situation, brk() and mmap space is shared and there are no
912	artificial limits on brk size imposed by the kernel. What is more,
913	applications have started using transient allocations larger than the
914	128Kb as was imagined in 2001.
915
916	The price for mmap is also high now; each time glibc mmaps from the
917	kernel, the kernel is forced to zero out the memory it gives to the
918	application. Zeroing memory is expensive and eats a lot of cache and
919	memory bandwidth. This has nothing to do with the efficiency of the
920	virtual memory system, by doing mmap the kernel just has no choice but
921	to zero.
922
923	In 2001, the kernel had a maximum size for brk() which was about 800
924	megabytes on 32 bit x86, at that point brk() would hit the first
925	mmaped shared libaries and couldn't expand anymore. With current 2.6
926	kernels, the VA space layout is different and brk() and mmap
927	both can span the entire heap at will.
928
929	Rather than using a static threshold for the brk/mmap tradeoff,
930	we are now using a simple dynamic one. The goal is still to avoid
931	fragmentation. The old goals we kept are
932	1) try to get the long lived large allocations to use mmap()
933	2) really large allocations should always use mmap()
934	and we're adding now:
935	3) transient allocations should use brk() to avoid forcing the kernel
936	having to zero memory over and over again
937
938	The implementation works with a sliding threshold, which is by default
939	limited to go between 128Kb and 32Mb (64Mb for 64 bitmachines) and starts
940	out at 128Kb as per the 2001 default.
941
942	This allows us to satisfy requirement 1) under the assumption that long
943	lived allocations are made early in the process' lifespan, before it has
944	started doing dynamic allocations of the same size (which will
945	increase the threshold).
946
947	The upperbound on the threshold satisfies requirement 2)
948
949	The threshold goes up in value when the application frees memory that was
950	allocated with the mmap allocator. The idea is that once the application
951	starts freeing memory of a certain size, it's highly probable that this is
952	a size the application uses for transient allocations. This estimator
953	is there to satisfy the new third requirement.
954
955	*/
956
957	#define M_MMAP_THRESHOLD -3
958
959	#ifndef DEFAULT_MMAP_THRESHOLD
960	#define DEFAULT_MMAP_THRESHOLD DEFAULT_MMAP_THRESHOLD_MIN
961	#endif
962
963	/*
964	M_MMAP_MAX is the maximum number of requests to simultaneously
965	service using mmap. This parameter exists because
966	some systems have a limited number of internal tables for
967	use by mmap, and using more than a few of them may degrade
968	performance.
969
970	The default is set to a value that serves only as a safeguard.
971	Setting to 0 disables use of mmap for servicing large requests.
972	*/
973
974	#define M_MMAP_MAX -4
975
976	#ifndef DEFAULT_MMAP_MAX
977	#define DEFAULT_MMAP_MAX (65536)
978	#endif
979
980	#include <malloc.h>
981
982	#ifndef RETURN_ADDRESS
983	#define RETURN_ADDRESS(X_) (NULL)
984	#endif
985
986	/ Forward declarations. /
987	struct malloc_chunk;
988	typedef struct malloc_chunk* mchunkptr;
989
990	/ Internal routines. /
991
992	static void* _int_malloc(mstate, size_t);
993	static void _int_free(mstate, mchunkptr, int);
994	static void* _int_realloc(mstate, mchunkptr, INTERNAL_SIZE_T,
995	INTERNAL_SIZE_T);
996	static void* _int_memalign(mstate, size_t, size_t);
997	static void* _mid_memalign(size_t, size_t, void *);
998
999	static void malloc_printerr(const char str) __attribute__* ((noreturn));
1000
1001	static void* mem2mem_check(void *p, size_t sz);
1002	static void top_check(void);
1003	static void munmap_chunk(mchunkptr p);
1004	#if HAVE_MREMAP
1005	static mchunkptr mremap_chunk(mchunkptr p, size_t new_size);
1006	#endif
1007
1008	static void* malloc_check(size_t sz, const void *caller);
1009	static void free_check(void* mem, const void *caller);
1010	static void* realloc_check(void* oldmem, size_t bytes,
1011	const void *caller);
1012	static void* memalign_check(size_t alignment, size_t bytes,
1013	const void *caller);
1014
1015	/ ------------------ MMAP support ------------------ /
1016
1017
1018	#include <fcntl.h>
1019	#include <sys/mman.h>
1020
1021	#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
1022	# define MAP_ANONYMOUS MAP_ANON
1023	#endif
1024
1025	#ifndef MAP_NORESERVE
1026	# define MAP_NORESERVE 0
1027	#endif
1028
1029	#define MMAP(addr, size, prot, flags) \
1030	__mmap((addr), (size), (prot), (flags)\|MAP_ANONYMOUS\|MAP_PRIVATE, -1, 0)
1031
1032
1033	/*
1034	----------------------- Chunk representations -----------------------
1035	*/
1036
1037
1038	/*
1039	This struct declaration is misleading (but accurate and necessary).
1040	It declares a "view" into memory allowing access to necessary
1041	fields at known offsets from a given base. See explanation below.
1042	*/
1043
1044	struct malloc_chunk {
1045
1046	INTERNAL_SIZE_T mchunk_prev_size; / Size of previous chunk (if free). /
1047	INTERNAL_SIZE_T mchunk_size; / Size in bytes, including overhead. /
1048
1049	struct malloc_chunk* fd; / double links -- used only if free. /
1050	struct malloc_chunk* bk;
1051
1052	/ Only used for large blocks: pointer to next larger size. /
1053	struct malloc_chunk* fd_nextsize; / double links -- used only if free. /
1054	struct malloc_chunk* bk_nextsize;
1055	};
1056
1057
1058	/*
1059	malloc_chunk details:
1060
1061	(The following includes lightly edited explanations by Colin Plumb.)
1062
1063	Chunks of memory are maintained using a `boundary tag' method as
1064	described in e.g., Knuth or Standish. (See the paper by Paul
1065	Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
1066	survey of such techniques.) Sizes of free chunks are stored both
1067	in the front of each chunk and at the end. This makes
1068	consolidating fragmented chunks into bigger chunks very fast. The
1069	size fields also hold bits representing whether chunks are free or
1070	in use.
1071
1072	An allocated chunk looks like this:
1073
1074
1075	chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1076	\| Size of previous chunk, if unallocated (P clear) \|
1077	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1078	\| Size of chunk, in bytes \|A\|M\|P\|
1079	mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1080	\| User data starts here... .
1081	. .
1082	. (malloc_usable_size() bytes) .
1083	. \|
1084	nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1085	\| (size of chunk, but used for application data) \|
1086	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1087	\| Size of next chunk, in bytes \|A\|0\|1\|
1088	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1089
1090	Where "chunk" is the front of the chunk for the purpose of most of
1091	the malloc code, but "mem" is the pointer that is returned to the
1092	user. "Nextchunk" is the beginning of the next contiguous chunk.
1093
1094	Chunks always begin on even word boundaries, so the mem portion
1095	(which is returned to the user) is also on an even word boundary, and
1096	thus at least double-word aligned.
1097
1098	Free chunks are stored in circular doubly-linked lists, and look like this:
1099
1100	chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1101	\| Size of previous chunk, if unallocated (P clear) \|
1102	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1103	`head:' \| Size of chunk, in bytes \|A\|0\|P\|
1104	mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1105	\| Forward pointer to next chunk in list \|
1106	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1107	\| Back pointer to previous chunk in list \|
1108	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1109	\| Unused space (may be 0 bytes long) .
1110	. .
1111	. \|
1112	nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1113	`foot:' \| Size of chunk, in bytes \|
1114	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1115	\| Size of next chunk, in bytes \|A\|0\|0\|
1116	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1117
1118	The P (PREV_INUSE) bit, stored in the unused low-order bit of the
1119	chunk size (which is always a multiple of two words), is an in-use
1120	bit for the previous* chunk. If that bit is clear, then the*
1121	word before the current chunk size contains the previous chunk
1122	size, and can be used to find the front of the previous chunk.
1123	The very first chunk allocated always has this bit set,
1124	preventing access to non-existent (or non-owned) memory. If
1125	prev_inuse is set for any given chunk, then you CANNOT determine
1126	the size of the previous chunk, and might even get a memory
1127	addressing fault when trying to do so.
1128
1129	The A (NON_MAIN_ARENA) bit is cleared for chunks on the initial,
1130	main arena, described by the main_arena variable. When additional
1131	threads are spawned, each thread receives its own arena (up to a
1132	configurable limit, after which arenas are reused for multiple
1133	threads), and the chunks in these arenas have the A bit set. To
1134	find the arena for a chunk on such a non-main arena, heap_for_ptr
1135	performs a bit mask operation and indirection through the ar_ptr
1136	member of the per-heap header heap_info (see arena.c).
1137
1138	Note that the `foot' of the current chunk is actually represented
1139	as the prev_size of the NEXT chunk. This makes it easier to
1140	deal with alignments etc but can be very confusing when trying
1141	to extend or adapt this code.
1142
1143	The three exceptions to all this are:
1144
1145	1. The special chunk `top' doesn't bother using the
1146	trailing size field since there is no next contiguous chunk
1147	that would have to index off it. After initialization, `top'
1148	is forced to always exist. If it would become less than
1149	MINSIZE bytes long, it is replenished.
1150
1151	2. Chunks allocated via mmap, which have the second-lowest-order
1152	bit M (IS_MMAPPED) set in their size fields. Because they are
1153	allocated one-by-one, each must contain its own trailing size
1154	field. If the M bit is set, the other bits are ignored
1155	(because mmapped chunks are neither in an arena, nor adjacent
1156	to a freed chunk). The M bit is also used for chunks which
1157	originally came from a dumped heap via malloc_set_state in
1158	hooks.c.
1159
1160	3. Chunks in fastbins are treated as allocated chunks from the
1161	point of view of the chunk allocator. They are consolidated
1162	with their neighbors only in bulk, in malloc_consolidate.
1163	*/
1164
1165	/*
1166	---------- Size and alignment checks and conversions ----------
1167	*/
1168
1169	/ conversion from malloc headers to user pointers, and back /
1170
1171	#define chunk2mem(p) ((void)((char)(p) + 2*SIZE_SZ))
1172	#define mem2chunk(mem) ((mchunkptr)((char)(mem) - 2SIZE_SZ))
1173
1174	/ The smallest possible chunk /
1175	#define MIN_CHUNK_SIZE (offsetof(struct malloc_chunk, fd_nextsize))
1176
1177	/ The smallest size we can malloc is an aligned minimal chunk /
1178
1179	#define MINSIZE \
1180	(unsigned long)(((MIN_CHUNK_SIZE+MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK))
1181
1182	/ Check if m has acceptable alignment /
1183
1184	#define aligned_OK(m) (((unsigned long)(m) & MALLOC_ALIGN_MASK) == 0)
1185
1186	#define misaligned_chunk(p) \
1187	((uintptr_t)(MALLOC_ALIGNMENT == 2 * SIZE_SZ ? (p) : chunk2mem (p)) \
1188	& MALLOC_ALIGN_MASK)
1189
1190
1191	/*
1192	Check if a request is so large that it would wrap around zero when
1193	padded and aligned. To simplify some other code, the bound is made
1194	low enough so that adding MINSIZE will also not wrap around zero.
1195	*/
1196
1197	#define REQUEST_OUT_OF_RANGE(req) \
1198	((unsigned long) (req) >= \
1199	(unsigned long) (INTERNAL_SIZE_T) (-2 * MINSIZE))
1200
1201	/ pad request bytes into a usable size -- internal version /
1202
1203	#define request2size(req) \
1204	(((req) + SIZE_SZ + MALLOC_ALIGN_MASK < MINSIZE) ? \
1205	MINSIZE : \
1206	((req) + SIZE_SZ + MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK)
1207
1208	/ Same, except also perform an argument and result check. First, we check*
1209	that the padding done by request2size didn't result in an integer
1210	overflow. Then we check (using REQUEST_OUT_OF_RANGE) that the resulting
1211	size isn't so large that a later alignment would lead to another integer
1212	overflow. /*
1213	#define checked_request2size(req, sz) \
1214	({ \
1215	(sz) = request2size (req); \
1216	if (((sz) < (req)) \
1217	\|\| REQUEST_OUT_OF_RANGE (sz)) \
1218	{ \
1219	__set_errno (ENOMEM); \
1220	return 0; \
1221	} \
1222	})
1223
1224	/*
1225	--------------- Physical chunk operations ---------------
1226	*/
1227
1228
1229	/ size field is or'ed with PREV_INUSE when previous adjacent chunk in use /
1230	#define PREV_INUSE 0x1
1231
1232	/ extract inuse bit of previous chunk /
1233	#define prev_inuse(p) ((p)->mchunk_size & PREV_INUSE)
1234
1235
1236	/ size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() /
1237	#define IS_MMAPPED 0x2
1238
1239	/ check for mmap()'ed chunk /
1240	#define chunk_is_mmapped(p) ((p)->mchunk_size & IS_MMAPPED)
1241
1242
1243	/ size field is or'ed with NON_MAIN_ARENA if the chunk was obtained*
1244	from a non-main arena. This is only set immediately before handing
1245	the chunk to the user, if necessary. /*
1246	#define NON_MAIN_ARENA 0x4
1247
1248	/ Check for chunk from main arena. /
1249	#define chunk_main_arena(p) (((p)->mchunk_size & NON_MAIN_ARENA) == 0)
1250
1251	/ Mark a chunk as not being on the main arena. /
1252	#define set_non_main_arena(p) ((p)->mchunk_size \|= NON_MAIN_ARENA)
1253
1254
1255	/*
1256	Bits to mask off when extracting size
1257
1258	Note: IS_MMAPPED is intentionally not masked off from size field in
1259	macros for which mmapped chunks should never be seen. This should
1260	cause helpful core dumps to occur if it is tried by accident by
1261	people extending or adapting this malloc.
1262	*/
1263	#define SIZE_BITS (PREV_INUSE \| IS_MMAPPED \| NON_MAIN_ARENA)
1264
1265	/ Get size, ignoring use bits /
1266	#define chunksize(p) (chunksize_nomask (p) & ~(SIZE_BITS))
1267
1268	/ Like chunksize, but do not mask SIZE_BITS. /
1269	#define chunksize_nomask(p) ((p)->mchunk_size)
1270
1271	/ Ptr to next physical malloc_chunk. /
1272	#define next_chunk(p) ((mchunkptr) (((char *) (p)) + chunksize (p)))
1273
1274	/ Size of the chunk below P. Only valid if !prev_inuse (P). /
1275	#define prev_size(p) ((p)->mchunk_prev_size)
1276
1277	/ Set the size of the chunk below P. Only valid if !prev_inuse (P). /
1278	#define set_prev_size(p, sz) ((p)->mchunk_prev_size = (sz))
1279
1280	/ Ptr to previous physical malloc_chunk. Only valid if !prev_inuse (P). /
1281	#define prev_chunk(p) ((mchunkptr) (((char *) (p)) - prev_size (p)))
1282
1283	/ Treat space at ptr + offset as a chunk /
1284	#define chunk_at_offset(p, s) ((mchunkptr) (((char *) (p)) + (s)))
1285
1286	/ extract p's inuse bit /
1287	#define inuse(p) \
1288	((((mchunkptr) (((char *) (p)) + chunksize (p)))->mchunk_size) & PREV_INUSE)
1289
1290	/ set/clear chunk as being inuse without otherwise disturbing /
1291	#define set_inuse(p) \
1292	((mchunkptr) (((char *) (p)) + chunksize (p)))->mchunk_size \|= PREV_INUSE
1293
1294	#define clear_inuse(p) \
1295	((mchunkptr) (((char *) (p)) + chunksize (p)))->mchunk_size &= ~(PREV_INUSE)
1296
1297
1298	/ check/set/clear inuse bits in known places /
1299	#define inuse_bit_at_offset(p, s) \
1300	(((mchunkptr) (((char *) (p)) + (s)))->mchunk_size & PREV_INUSE)
1301
1302	#define set_inuse_bit_at_offset(p, s) \
1303	(((mchunkptr) (((char *) (p)) + (s)))->mchunk_size \|= PREV_INUSE)
1304
1305	#define clear_inuse_bit_at_offset(p, s) \
1306	(((mchunkptr) (((char *) (p)) + (s)))->mchunk_size &= ~(PREV_INUSE))
1307
1308
1309	/ Set size at head, without disturbing its use bit /
1310	#define set_head_size(p, s) ((p)->mchunk_size = (((p)->mchunk_size & SIZE_BITS) \| (s)))
1311
1312	/ Set size/use field /
1313	#define set_head(p, s) ((p)->mchunk_size = (s))
1314
1315	/ Set size at footer (only when chunk is not in use) /
1316	#define set_foot(p, s) (((mchunkptr) ((char *) (p) + (s)))->mchunk_prev_size = (s))
1317
1318
1319	#pragma GCC poison mchunk_size
1320	#pragma GCC poison mchunk_prev_size
1321
1322	/*
1323	-------------------- Internal data structures --------------------
1324
1325	All internal state is held in an instance of malloc_state defined
1326	below. There are no other static variables, except in two optional
1327	cases:
1328	* If USE_MALLOC_LOCK is defined, the mALLOC_MUTEx declared above.
1329	* If mmap doesn't support MAP_ANONYMOUS, a dummy file descriptor
1330	for mmap.
1331
1332	Beware of lots of tricks that minimize the total bookkeeping space
1333	requirements. The result is a little over 1K bytes (for 4byte
1334	pointers and size_t.)
1335	*/
1336
1337	/*
1338	Bins
1339
1340	An array of bin headers for free chunks. Each bin is doubly
1341	linked. The bins are approximately proportionally (log) spaced.
1342	There are a lot of these bins (128). This may look excessive, but
1343	works very well in practice. Most bins hold sizes that are
1344	unusual as malloc request sizes, but are more usual for fragments
1345	and consolidated sets of chunks, which is what these bins hold, so
1346	they can be found quickly. All procedures maintain the invariant
1347	that no consolidated chunk physically borders another one, so each
1348	chunk in a list is known to be preceeded and followed by either
1349	inuse chunks or the ends of memory.
1350
1351	Chunks in bins are kept in size order, with ties going to the
1352	approximately least recently used chunk. Ordering isn't needed
1353	for the small bins, which all contain the same-sized chunks, but
1354	facilitates best-fit allocation for larger chunks. These lists
1355	are just sequential. Keeping them in order almost never requires
1356	enough traversal to warrant using fancier ordered data
1357	structures.
1358
1359	Chunks of the same size are linked with the most
1360	recently freed at the front, and allocations are taken from the
1361	back. This results in LRU (FIFO) allocation order, which tends
1362	to give each chunk an equal opportunity to be consolidated with
1363	adjacent freed chunks, resulting in larger free chunks and less
1364	fragmentation.
1365
1366	To simplify use in double-linked lists, each bin header acts
1367	as a malloc_chunk. This avoids special-casing for headers.
1368	But to conserve space and improve locality, we allocate
1369	only the fd/bk pointers of bins, and then use repositioning tricks
1370	to treat these as the fields of a malloc_chunk.*
1371	*/
1372
1373	typedef struct malloc_chunk *mbinptr;
1374
1375	/ addressing -- note that bin_at(0) does not exist /
1376	#define bin_at(m, i) \
1377	(mbinptr) (((char ) &((m)->bins[((i) - 1) 2])) \
1378	- offsetof (struct malloc_chunk, fd))
1379
1380	/ analog of ++bin /
1381	#define next_bin(b) ((mbinptr) ((char *) (b) + (sizeof (mchunkptr) << 1)))
1382
1383	/ Reminders about list directionality within bins /
1384	#define first(b) ((b)->fd)
1385	#define last(b) ((b)->bk)
1386
1387	/*
1388	Indexing
1389
1390	Bins for sizes < 512 bytes contain chunks of all the same size, spaced
1391	8 bytes apart. Larger bins are approximately logarithmically spaced:
1392
1393	64 bins of size 8
1394	32 bins of size 64
1395	16 bins of size 512
1396	8 bins of size 4096
1397	4 bins of size 32768
1398	2 bins of size 262144
1399	1 bin of size what's left
1400
1401	There is actually a little bit of slop in the numbers in bin_index
1402	for the sake of speed. This makes no difference elsewhere.
1403
1404	The bins top out around 1MB because we expect to service large
1405	requests via mmap.
1406
1407	Bin 0 does not exist. Bin 1 is the unordered list; if that would be
1408	a valid chunk size the small bins are bumped up one.
1409	*/
1410
1411	#define NBINS 128
1412	#define NSMALLBINS 64
1413	#define SMALLBIN_WIDTH MALLOC_ALIGNMENT
1414	#define SMALLBIN_CORRECTION (MALLOC_ALIGNMENT > 2 * SIZE_SZ)
1415	#define MIN_LARGE_SIZE ((NSMALLBINS - SMALLBIN_CORRECTION) * SMALLBIN_WIDTH)
1416
1417	#define in_smallbin_range(sz) \
1418	((unsigned long) (sz) < (unsigned long) MIN_LARGE_SIZE)
1419
1420	#define smallbin_index(sz) \
1421	((SMALLBIN_WIDTH == 16 ? (((unsigned) (sz)) >> 4) : (((unsigned) (sz)) >> 3))\
1422	+ SMALLBIN_CORRECTION)
1423
1424	#define largebin_index_32(sz) \
1425	(((((unsigned long) (sz)) >> 6) <= 38) ? 56 + (((unsigned long) (sz)) >> 6) :\
1426	((((unsigned long) (sz)) >> 9) <= 20) ? 91 + (((unsigned long) (sz)) >> 9) :\
1427	((((unsigned long) (sz)) >> 12) <= 10) ? 110 + (((unsigned long) (sz)) >> 12) :\
1428	((((unsigned long) (sz)) >> 15) <= 4) ? 119 + (((unsigned long) (sz)) >> 15) :\
1429	((((unsigned long) (sz)) >> 18) <= 2) ? 124 + (((unsigned long) (sz)) >> 18) :\
1430	126)
1431
1432	#define largebin_index_32_big(sz) \
1433	(((((unsigned long) (sz)) >> 6) <= 45) ? 49 + (((unsigned long) (sz)) >> 6) :\
1434	((((unsigned long) (sz)) >> 9) <= 20) ? 91 + (((unsigned long) (sz)) >> 9) :\
1435	((((unsigned long) (sz)) >> 12) <= 10) ? 110 + (((unsigned long) (sz)) >> 12) :\
1436	((((unsigned long) (sz)) >> 15) <= 4) ? 119 + (((unsigned long) (sz)) >> 15) :\
1437	((((unsigned long) (sz)) >> 18) <= 2) ? 124 + (((unsigned long) (sz)) >> 18) :\
1438	126)
1439
1440	// XXX It remains to be seen whether it is good to keep the widths of
1441	// XXX the buckets the same or whether it should be scaled by a factor
1442	// XXX of two as well.
1443	#define largebin_index_64(sz) \
1444	(((((unsigned long) (sz)) >> 6) <= 48) ? 48 + (((unsigned long) (sz)) >> 6) :\
1445	((((unsigned long) (sz)) >> 9) <= 20) ? 91 + (((unsigned long) (sz)) >> 9) :\
1446	((((unsigned long) (sz)) >> 12) <= 10) ? 110 + (((unsigned long) (sz)) >> 12) :\
1447	((((unsigned long) (sz)) >> 15) <= 4) ? 119 + (((unsigned long) (sz)) >> 15) :\
1448	((((unsigned long) (sz)) >> 18) <= 2) ? 124 + (((unsigned long) (sz)) >> 18) :\
1449	126)
1450
1451	#define largebin_index(sz) \
1452	(SIZE_SZ == 8 ? largebin_index_64 (sz) \
1453	: MALLOC_ALIGNMENT == 16 ? largebin_index_32_big (sz) \
1454	: largebin_index_32 (sz))
1455
1456	#define bin_index(sz) \
1457	((in_smallbin_range (sz)) ? smallbin_index (sz) : largebin_index (sz))
1458
1459	/ Take a chunk off a bin list. /
1460	static void
1461	unlink_chunk (mstate av, mchunkptr p)
1462	{
1463	if (chunksize (p) != prev_size (next_chunk (p)))
1464	malloc_printerr ("corrupted size vs. prev_size");
1465
1466	mchunkptr fd = p->fd;
1467	mchunkptr bk = p->bk;
1468
1469	if (__builtin_expect (fd->bk != p \|\| bk->fd != p, `0`))
1470	malloc_printerr ("corrupted double-linked list");
1471
1472	fd->bk = bk;
1473	bk->fd = fd;
1474	if (!in_smallbin_range (chunksize_nomask (p)) && p->fd_nextsize != NULL)
1475	{
1476	if (p->fd_nextsize->bk_nextsize != p
1477	\|\| p->bk_nextsize->fd_nextsize != p)
1478	malloc_printerr ("corrupted double-linked list (not small)");
1479
1480	if (fd->fd_nextsize == NULL)
1481	{
1482	if (p->fd_nextsize == p)
1483	fd->fd_nextsize = fd->bk_nextsize = fd;
1484	else
1485	{
1486	fd->fd_nextsize = p->fd_nextsize;
1487	fd->bk_nextsize = p->bk_nextsize;
1488	p->fd_nextsize->bk_nextsize = fd;
1489	p->bk_nextsize->fd_nextsize = fd;
1490	}
1491	}
1492	else
1493	{
1494	p->fd_nextsize->bk_nextsize = p->bk_nextsize;
1495	p->bk_nextsize->fd_nextsize = p->fd_nextsize;
1496	}
1497	}
1498	}
1499
1500	/*
1501	Unsorted chunks
1502
1503	All remainders from chunk splits, as well as all returned chunks,
1504	are first placed in the "unsorted" bin. They are then placed
1505	in regular bins after malloc gives them ONE chance to be used before
1506	binning. So, basically, the unsorted_chunks list acts as a queue,
1507	with chunks being placed on it in free (and malloc_consolidate),
1508	and taken off (to be either used or placed in bins) in malloc.
1509
1510	The NON_MAIN_ARENA flag is never set for unsorted chunks, so it
1511	does not have to be taken into account in size comparisons.
1512	*/
1513
1514	/ The otherwise unindexable 1-bin is used to hold unsorted chunks. /
1515	#define unsorted_chunks(M) (bin_at (M, 1))
1516
1517	/*
1518	Top
1519
1520	The top-most available chunk (i.e., the one bordering the end of
1521	available memory) is treated specially. It is never included in
1522	any bin, is used only if no other chunk is available, and is
1523	released back to the system if it is very large (see
1524	M_TRIM_THRESHOLD). Because top initially
1525	points to its own bin with initial zero size, thus forcing
1526	extension on the first malloc request, we avoid having any special
1527	code in malloc to check whether it even exists yet. But we still
1528	need to do so when getting memory from system, so we make
1529	initial_top treat the bin as a legal but unusable chunk during the
1530	interval between initialization and the first call to
1531	sysmalloc. (This is somewhat delicate, since it relies on
1532	the 2 preceding words to be zero during this interval as well.)
1533	*/
1534
1535	/ Conveniently, the unsorted bin can be used as dummy top on first call /
1536	#define initial_top(M) (unsorted_chunks (M))
1537
1538	/*
1539	Binmap
1540
1541	To help compensate for the large number of bins, a one-level index
1542	structure is used for bin-by-bin searching. `binmap' is a
1543	bitvector recording whether bins are definitely empty so they can
1544	be skipped over during during traversals. The bits are NOT always
1545	cleared as soon as bins are empty, but instead only
1546	when they are noticed to be empty during traversal in malloc.
1547	*/
1548
1549	/ Conservatively use 32 bits per map word, even if on 64bit system /
1550	#define BINMAPSHIFT 5
1551	#define BITSPERMAP (1U << BINMAPSHIFT)
1552	#define BINMAPSIZE (NBINS / BITSPERMAP)
1553
1554	#define idx2block(i) ((i) >> BINMAPSHIFT)
1555	#define idx2bit(i) ((1U << ((i) & ((1U << BINMAPSHIFT) - 1))))
1556
1557	#define mark_bin(m, i) ((m)->binmap[idx2block (i)] \|= idx2bit (i))
1558	#define unmark_bin(m, i) ((m)->binmap[idx2block (i)] &= ~(idx2bit (i)))
1559	#define get_binmap(m, i) ((m)->binmap[idx2block (i)] & idx2bit (i))
1560
1561	/*
1562	Fastbins
1563
1564	An array of lists holding recently freed small chunks. Fastbins
1565	are not doubly linked. It is faster to single-link them, and
1566	since chunks are never removed from the middles of these lists,
1567	double linking is not necessary. Also, unlike regular bins, they
1568	are not even processed in FIFO order (they use faster LIFO) since
1569	ordering doesn't much matter in the transient contexts in which
1570	fastbins are normally used.
1571
1572	Chunks in fastbins keep their inuse bit set, so they cannot
1573	be consolidated with other free chunks. malloc_consolidate
1574	releases all chunks in fastbins and consolidates them with
1575	other free chunks.
1576	*/
1577
1578	typedef struct malloc_chunk *mfastbinptr;
1579	#define fastbin(ar_ptr, idx) ((ar_ptr)->fastbinsY[idx])
1580
1581	/ offset 2 to use otherwise unindexable first 2 bins /
1582	#define fastbin_index(sz) \
1583	((((unsigned int) (sz)) >> (SIZE_SZ == 8 ? 4 : 3)) - 2)
1584
1585
1586	/ The maximum fastbin request size we support /
1587	#define MAX_FAST_SIZE (80 * SIZE_SZ / 4)
1588
1589	#define NFASTBINS (fastbin_index (request2size (MAX_FAST_SIZE)) + 1)
1590
1591	/*
1592	FASTBIN_CONSOLIDATION_THRESHOLD is the size of a chunk in free()
1593	that triggers automatic consolidation of possibly-surrounding
1594	fastbin chunks. This is a heuristic, so the exact value should not
1595	matter too much. It is defined at half the default trim threshold as a
1596	compromise heuristic to only attempt consolidation if it is likely
1597	to lead to trimming. However, it is not dynamically tunable, since
1598	consolidation reduces fragmentation surrounding large chunks even
1599	if trimming is not used.
1600	*/
1601
1602	#define FASTBIN_CONSOLIDATION_THRESHOLD (65536UL)
1603
1604	/*
1605	NONCONTIGUOUS_BIT indicates that MORECORE does not return contiguous
1606	regions. Otherwise, contiguity is exploited in merging together,
1607	when possible, results from consecutive MORECORE calls.
1608
1609	The initial value comes from MORECORE_CONTIGUOUS, but is
1610	changed dynamically if mmap is ever used as an sbrk substitute.
1611	*/
1612
1613	#define NONCONTIGUOUS_BIT (2U)
1614
1615	#define contiguous(M) (((M)->flags & NONCONTIGUOUS_BIT) == 0)
1616	#define noncontiguous(M) (((M)->flags & NONCONTIGUOUS_BIT) != 0)
1617	#define set_noncontiguous(M) ((M)->flags \|= NONCONTIGUOUS_BIT)
1618	#define set_contiguous(M) ((M)->flags &= ~NONCONTIGUOUS_BIT)
1619
1620	/ Maximum size of memory handled in fastbins. /
1621	static INTERNAL_SIZE_T global_max_fast;
1622
1623	/*
1624	Set value of max_fast.
1625	Use impossibly small value if 0.
1626	Precondition: there are no existing fastbin chunks in the main arena.
1627	Since do_check_malloc_state () checks this, we call malloc_consolidate ()
1628	before changing max_fast. Note other arenas will leak their fast bin
1629	entries if max_fast is reduced.
1630	*/
1631
1632	#define set_max_fast(s) \
1633	global_max_fast = (((s) == 0) \
1634	? SMALLBIN_WIDTH : ((s + SIZE_SZ) & ~MALLOC_ALIGN_MASK))
1635
1636	static inline INTERNAL_SIZE_T
1637	get_max_fast (void)
1638	{
1639	/ Tell the GCC optimizers that global_max_fast is never larger*
1640	than MAX_FAST_SIZE. This avoids out-of-bounds array accesses in
1641	_int_malloc after constant propagation of the size parameter.
1642	(The code never executes because malloc preserves the
1643	global_max_fast invariant, but the optimizers may not recognize
1644	this.) /*
1645	if (global_max_fast > MAX_FAST_SIZE)
1646	__builtin_unreachable ();
1647	return global_max_fast;
1648	}
1649
1650	/*
1651	----------- Internal state representation and initialization -----------
1652	*/
1653
1654	/*
1655	have_fastchunks indicates that there are probably some fastbin chunks.
1656	It is set true on entering a chunk into any fastbin, and cleared early in
1657	malloc_consolidate. The value is approximate since it may be set when there
1658	are no fastbin chunks, or it may be clear even if there are fastbin chunks
1659	available. Given it's sole purpose is to reduce number of redundant calls to
1660	malloc_consolidate, it does not affect correctness. As a result we can safely
1661	use relaxed atomic accesses.
1662	*/
1663
1664
1665	struct malloc_state
1666	{
1667	/ Serialize access. /
1668	__libc_lock_define (, mutex);
1669
1670	/ Flags (formerly in max_fast). /
1671	int flags;
1672
1673	/ Set if the fastbin chunks contain recently inserted free blocks. /
1674	/ Note this is a bool but not all targets support atomics on booleans. /
1675	int have_fastchunks;
1676
1677	/ Fastbins /
1678	mfastbinptr fastbinsY[NFASTBINS];
1679
1680	/ Base of the topmost chunk -- not otherwise kept in a bin /
1681	mchunkptr top;
1682
1683	/ The remainder from the most recent split of a small request /
1684	mchunkptr last_remainder;
1685
1686	/ Normal bins packed as described above /
1687	mchunkptr bins[NBINS * `2` - `2`];
1688
1689	/ Bitmap of bins /
1690	unsigned int binmap[BINMAPSIZE];
1691
1692	/ Linked list /
1693	struct malloc_state *next;
1694
1695	/ Linked list for free arenas. Access to this field is serialized*
1696	by free_list_lock in arena.c. /*
1697	struct malloc_state *next_free;
1698
1699	/ Number of threads attached to this arena. 0 if the arena is on*
1700	the free list. Access to this field is serialized by
1701	free_list_lock in arena.c. /*
1702	INTERNAL_SIZE_T attached_threads;
1703
1704	/ Memory allocated from the system in this arena. /
1705	INTERNAL_SIZE_T system_mem;
1706	INTERNAL_SIZE_T max_system_mem;
1707	};
1708
1709	struct malloc_par
1710	{
1711	/ Tunable parameters /
1712	unsigned long trim_threshold;
1713	INTERNAL_SIZE_T top_pad;
1714	INTERNAL_SIZE_T mmap_threshold;
1715	INTERNAL_SIZE_T arena_test;
1716	INTERNAL_SIZE_T arena_max;
1717
1718	/ Memory map support /
1719	int n_mmaps;
1720	int n_mmaps_max;
1721	int max_n_mmaps;
1722	/ the mmap_threshold is dynamic, until the user sets*
1723	it manually, at which point we need to disable any
1724	dynamic behavior. /*
1725	int no_dyn_threshold;
1726
1727	/ Statistics /
1728	INTERNAL_SIZE_T mmapped_mem;
1729	INTERNAL_SIZE_T max_mmapped_mem;
1730
1731	/ First address handed out by MORECORE/sbrk. /
1732	char *sbrk_base;
1733
1734	#if USE_TCACHE
1735	/ Maximum number of buckets to use. /
1736	size_t tcache_bins;
1737	size_t tcache_max_bytes;
1738	/ Maximum number of chunks in each bucket. /
1739	size_t tcache_count;
1740	/ Maximum number of chunks to remove from the unsorted list, which*
1741	aren't used to prefill the cache. /*
1742	size_t tcache_unsorted_limit;
1743	#endif
1744	};
1745
1746	/ There are several instances of this struct ("arenas") in this*
1747	malloc. If you are adapting this malloc in a way that does NOT use
1748	a static or mmapped malloc_state, you MUST explicitly zero-fill it
1749	before using. This malloc relies on the property that malloc_state
1750	is initialized to all zeroes (as is true of C statics). /*
1751
1752	static struct malloc_state main_arena =
1753	{
1754	.mutex = _LIBC_LOCK_INITIALIZER,
1755	.next = &main_arena,
1756	.attached_threads = `1`
1757	};
1758
1759	/ These variables are used for undumping support. Chunked are marked*
1760	as using mmap, but we leave them alone if they fall into this
1761	range. NB: The chunk size for these chunks only includes the
1762	initial size field (of SIZE_SZ bytes), there is no trailing size
1763	field (unlike with regular mmapped chunks). /*
1764	static mchunkptr dumped_main_arena_start; / Inclusive. /
1765	static mchunkptr dumped_main_arena_end; / Exclusive. /
1766
1767	/ True if the pointer falls into the dumped arena. Use this after*
1768	chunk_is_mmapped indicates a chunk is mmapped. /*
1769	#define DUMPED_MAIN_ARENA_CHUNK(p) \
1770	((p) >= dumped_main_arena_start && (p) < dumped_main_arena_end)
1771
1772	/ There is only one instance of the malloc parameters. /
1773
1774	static struct malloc_par mp_ =
1775	{
1776	.top_pad = DEFAULT_TOP_PAD,
1777	.n_mmaps_max = DEFAULT_MMAP_MAX,
1778	.mmap_threshold = DEFAULT_MMAP_THRESHOLD,
1779	.trim_threshold = DEFAULT_TRIM_THRESHOLD,
1780	#define NARENAS_FROM_NCORES(n) ((n) * (sizeof (long) == 4 ? 2 : 8))
1781	.arena_test = NARENAS_FROM_NCORES (`1`)
1782	#if USE_TCACHE
1783	,
1784	.tcache_count = TCACHE_FILL_COUNT,
1785	.tcache_bins = TCACHE_MAX_BINS,
1786	.tcache_max_bytes = tidx2usize (TCACHE_MAX_BINS-`1`),
1787	.tcache_unsorted_limit = `0` / No limit. /
1788	#endif
1789	};
1790
1791	/*
1792	Initialize a malloc_state struct.
1793
1794	This is called from ptmalloc_init () or from _int_new_arena ()
1795	when creating a new arena.
1796	*/
1797
1798	static void
1799	malloc_init_state (mstate av)
1800	{
1801	int i;
1802	mbinptr bin;
1803
1804	/ Establish circular links for normal bins /
1805	for (i = `1`; i < NBINS; ++i)
1806	{
1807	bin = bin_at (av, i);
1808	bin->fd = bin->bk = bin;
1809	}
1810
1811	#if MORECORE_CONTIGUOUS
1812	if (av != &main_arena)
1813	#endif
1814	set_noncontiguous (av);
1815	if (av == &main_arena)
1816	set_max_fast (DEFAULT_MXFAST);
1817	atomic_store_relaxed (&av->have_fastchunks, false);
1818
1819	av->top = initial_top (av);
1820	}
1821
1822	/*
1823	Other internal utilities operating on mstates
1824	*/
1825
1826	static void *sysmalloc (INTERNAL_SIZE_T, mstate);
1827	static int systrim (size_t, mstate);
1828	static void malloc_consolidate (mstate);
1829
1830
1831	/ -------------- Early definitions for debugging hooks ---------------- /
1832
1833	/ Define and initialize the hook variables. These weak definitions must*
1834	appear before any use of the variables in a function (arena.c uses one). /*
1835	#ifndef weak_variable
1836	/ In GNU libc we want the hook variables to be weak definitions to*
1837	avoid a problem with Emacs. /*
1838	# define weak_variable weak_function
1839	#endif
1840
1841	/ Forward declarations. /
1842	static void *malloc_hook_ini (size_t sz,
1843	const void *caller) __THROW;
1844	static void realloc_hook_ini (void* *ptr, size_t sz,
1845	const void *caller) __THROW;
1846	static void *memalign_hook_ini (size_t alignment, size_t sz,
1847	const void *caller) __THROW;
1848
1849	#if HAVE_MALLOC_INIT_HOOK
1850	void weak_variable (__malloc_initialize_hook) (void*) = NULL;
1851	compat_symbol (libc, __malloc_initialize_hook,
1852	__malloc_initialize_hook, GLIBC_2_0);
1853	#endif
1854
1855	void weak_variable (__free_hook) (void* *__ptr,
1856	const void *) = NULL;
1857	void weak_variable (__malloc_hook)
1858	(size_t __size, const void *) = malloc_hook_ini;
1859	void weak_variable (__realloc_hook)
1860	(void __ptr, size_t __size, const* void *)
1861	= realloc_hook_ini;
1862	void weak_variable (__memalign_hook)
1863	(size_t __alignment, size_t __size, const void *)
1864	= memalign_hook_ini;
1865	void weak_variable (__after_morecore_hook) (void*) = NULL;
1866
1867	/ This function is called from the arena shutdown hook, to free the*
1868	thread cache (if it exists). /*
1869	static void tcache_thread_shutdown (void);
1870
1871	/ ------------------ Testing support ----------------------------------/
1872
1873	static int perturb_byte;
1874
1875	static void
1876	alloc_perturb (char *p, size_t n)
1877	{
1878	if (__glibc_unlikely (perturb_byte))
1879	memset (p, perturb_byte ^ `0xff`, n);
1880	}
1881
1882	static void
1883	free_perturb (char *p, size_t n)
1884	{
1885	if (__glibc_unlikely (perturb_byte))
1886	memset (p, perturb_byte, n);
1887	}
1888
1889
1890
1891	#include <stap-probe.h>
1892
1893	/ ------------------- Support for multiple arenas -------------------- /
1894	#include "arena.c"
1895
1896	/*
1897	Debugging support
1898
1899	These routines make a number of assertions about the states
1900	of data structures that should be true at all times. If any
1901	are not true, it's very likely that a user program has somehow
1902	trashed memory. (It's also possible that there is a coding error
1903	in malloc. In which case, please report it!)
1904	*/
1905
1906	#if !MALLOC_DEBUG
1907
1908	# define check_chunk(A, P)
1909	# define check_free_chunk(A, P)
1910	# define check_inuse_chunk(A, P)
1911	# define check_remalloced_chunk(A, P, N)
1912	# define check_malloced_chunk(A, P, N)
1913	# define check_malloc_state(A)
1914
1915	#else
1916
1917	# define check_chunk(A, P) do_check_chunk (A, P)
1918	# define check_free_chunk(A, P) do_check_free_chunk (A, P)
1919	# define check_inuse_chunk(A, P) do_check_inuse_chunk (A, P)
1920	# define check_remalloced_chunk(A, P, N) do_check_remalloced_chunk (A, P, N)
1921	# define check_malloced_chunk(A, P, N) do_check_malloced_chunk (A, P, N)
1922	# define check_malloc_state(A) do_check_malloc_state (A)
1923
1924	/*
1925	Properties of all chunks
1926	*/
1927
1928	static void
1929	do_check_chunk (mstate av, mchunkptr p)
1930	{
1931	unsigned long sz = chunksize (p);
1932	/ min and max possible addresses assuming contiguous allocation /
1933	char max_address = (char* *) (av->top) + chunksize (av->top);
1934	char *min_address = max_address - av->system_mem;
1935
1936	if (!chunk_is_mmapped (p))
1937	{
1938	/ Has legal address ... /
1939	if (p != av->top)
1940	{
1941	if (contiguous (av))
1942	{
1943	assert (((char *) p) >= min_address);
1944	assert (((char ) p + sz) <= ((char* *) (av->top)));
1945	}
1946	}
1947	else
1948	{
1949	/ top size is always at least MINSIZE /
1950	assert ((unsigned long) (sz) >= MINSIZE);
1951	/ top predecessor always marked inuse /
1952	assert (prev_inuse (p));
1953	}
1954	}
1955	else if (!DUMPED_MAIN_ARENA_CHUNK (p))
1956	{
1957	/ address is outside main heap /
1958	if (contiguous (av) && av->top != initial_top (av))
1959	{
1960	assert (((char ) p) < min_address \|\| ((char* *) p) >= max_address);
1961	}
1962	/ chunk is page-aligned /
1963	assert (((prev_size (p) + sz) & (GLRO (dl_pagesize) - `1`)) == `0`);
1964	/ mem is aligned /
1965	assert (aligned_OK (chunk2mem (p)));
1966	}
1967	}
1968
1969	/*
1970	Properties of free chunks
1971	*/
1972
1973	static void
1974	do_check_free_chunk (mstate av, mchunkptr p)
1975	{
1976	INTERNAL_SIZE_T sz = chunksize_nomask (p) & ~(PREV_INUSE \| NON_MAIN_ARENA);
1977	mchunkptr next = chunk_at_offset (p, sz);
1978
1979	do_check_chunk (av, p);
1980
1981	/ Chunk must claim to be free ... /
1982	assert (!inuse (p));
1983	assert (!chunk_is_mmapped (p));
1984
1985	/ Unless a special marker, must have OK fields /
1986	if ((unsigned long) (sz) >= MINSIZE)
1987	{
1988	assert ((sz & MALLOC_ALIGN_MASK) == `0`);
1989	assert (aligned_OK (chunk2mem (p)));
1990	/ ... matching footer field /
1991	assert (prev_size (next_chunk (p)) == sz);
1992	/ ... and is fully consolidated /
1993	assert (prev_inuse (p));
1994	assert (next == av->top \|\| inuse (next));
1995
1996	/ ... and has minimally sane links /
1997	assert (p->fd->bk == p);
1998	assert (p->bk->fd == p);
1999	}
2000	else / markers are always of size SIZE_SZ /
2001	assert (sz == SIZE_SZ);
2002	}
2003
2004	/*
2005	Properties of inuse chunks
2006	*/
2007
2008	static void
2009	do_check_inuse_chunk (mstate av, mchunkptr p)
2010	{
2011	mchunkptr next;
2012
2013	do_check_chunk (av, p);
2014
2015	if (chunk_is_mmapped (p))
2016	return; / mmapped chunks have no next/prev /
2017
2018	/ Check whether it claims to be in use ... /
2019	assert (inuse (p));
2020
2021	next = next_chunk (p);
2022
2023	/ ... and is surrounded by OK chunks.*
2024	Since more things can be checked with free chunks than inuse ones,
2025	if an inuse chunk borders them and debug is on, it's worth doing them.
2026	*/
2027	if (!prev_inuse (p))
2028	{
2029	/ Note that we cannot even look at prev unless it is not inuse /
2030	mchunkptr prv = prev_chunk (p);
2031	assert (next_chunk (prv) == p);
2032	do_check_free_chunk (av, prv);
2033	}
2034
2035	if (next == av->top)
2036	{
2037	assert (prev_inuse (next));
2038	assert (chunksize (next) >= MINSIZE);
2039	}
2040	else if (!inuse (next))
2041	do_check_free_chunk (av, next);
2042	}
2043
2044	/*
2045	Properties of chunks recycled from fastbins
2046	*/
2047
2048	static void
2049	do_check_remalloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s)
2050	{
2051	INTERNAL_SIZE_T sz = chunksize_nomask (p) & ~(PREV_INUSE \| NON_MAIN_ARENA);
2052
2053	if (!chunk_is_mmapped (p))
2054	{
2055	assert (av == arena_for_chunk (p));
2056	if (chunk_main_arena (p))
2057	assert (av == &main_arena);
2058	else
2059	assert (av != &main_arena);
2060	}
2061
2062	do_check_inuse_chunk (av, p);
2063
2064	/ Legal size ... /
2065	assert ((sz & MALLOC_ALIGN_MASK) == `0`);
2066	assert ((unsigned long) (sz) >= MINSIZE);
2067	/ ... and alignment /
2068	assert (aligned_OK (chunk2mem (p)));
2069	/ chunk is less than MINSIZE more than request /
2070	assert ((long) (sz) - (long) (s) >= `0`);
2071	assert ((long) (sz) - (long) (s + MINSIZE) < `0`);
2072	}
2073
2074	/*
2075	Properties of nonrecycled chunks at the point they are malloced
2076	*/
2077
2078	static void
2079	do_check_malloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s)
2080	{
2081	/ same as recycled case ... /
2082	do_check_remalloced_chunk (av, p, s);
2083
2084	/*
2085	... plus, must obey implementation invariant that prev_inuse is
2086	always true of any allocated chunk; i.e., that each allocated
2087	chunk borders either a previously allocated and still in-use
2088	chunk, or the base of its memory arena. This is ensured
2089	by making all allocations from the `lowest' part of any found
2090	chunk. This does not necessarily hold however for chunks
2091	recycled via fastbins.
2092	*/
2093
2094	assert (prev_inuse (p));
2095	}
2096
2097
2098	/*
2099	Properties of malloc_state.
2100
2101	This may be useful for debugging malloc, as well as detecting user
2102	programmer errors that somehow write into malloc_state.
2103
2104	If you are extending or experimenting with this malloc, you can
2105	probably figure out how to hack this routine to print out or
2106	display chunk addresses, sizes, bins, and other instrumentation.
2107	*/
2108
2109	static void
2110	do_check_malloc_state (mstate av)
2111	{
2112	int i;
2113	mchunkptr p;
2114	mchunkptr q;
2115	mbinptr b;
2116	unsigned int idx;
2117	INTERNAL_SIZE_T size;
2118	unsigned long total = `0`;
2119	int max_fast_bin;
2120
2121	/ internal size_t must be no wider than pointer type /
2122	assert (sizeof (INTERNAL_SIZE_T) <= sizeof (char *));
2123
2124	/ alignment is a power of 2 /
2125	assert ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT - `1`)) == `0`);
2126
2127	/ Check the arena is initialized. /
2128	assert (av->top != `0`);
2129
2130	/ No memory has been allocated yet, so doing more tests is not possible. /
2131	if (av->top == initial_top (av))
2132	return;
2133
2134	/ pagesize is a power of 2 /
2135	assert (powerof2(GLRO (dl_pagesize)));
2136
2137	/ A contiguous main_arena is consistent with sbrk_base. /
2138	if (av == &main_arena && contiguous (av))
2139	assert ((char *) mp_.sbrk_base + av->system_mem ==
2140	(char *) av->top + chunksize (av->top));
2141
2142	/ properties of fastbins /
2143
2144	/ max_fast is in allowed range /
2145	assert ((get_max_fast () & ~`1`) <= request2size (MAX_FAST_SIZE));
2146
2147	max_fast_bin = fastbin_index (get_max_fast ());
2148
2149	for (i = `0`; i < NFASTBINS; ++i)
2150	{
2151	p = fastbin (av, i);
2152
2153	/ The following test can only be performed for the main arena.*
2154	While mallopt calls malloc_consolidate to get rid of all fast
2155	bins (especially those larger than the new maximum) this does
2156	only happen for the main arena. Trying to do this for any
2157	other arena would mean those arenas have to be locked and
2158	malloc_consolidate be called for them. This is excessive. And
2159	even if this is acceptable to somebody it still cannot solve
2160	the problem completely since if the arena is locked a
2161	concurrent malloc call might create a new arena which then
2162	could use the newly invalid fast bins. /*
2163
2164	/ all bins past max_fast are empty /
2165	if (av == &main_arena && i > max_fast_bin)
2166	assert (p == `0`);
2167
2168	while (p != `0`)
2169	{
2170	/ each chunk claims to be inuse /
2171	do_check_inuse_chunk (av, p);
2172	total += chunksize (p);
2173	/ chunk belongs in this bin /
2174	assert (fastbin_index (chunksize (p)) == i);
2175	p = p->fd;
2176	}
2177	}
2178
2179	/ check normal bins /
2180	for (i = `1`; i < NBINS; ++i)
2181	{
2182	b = bin_at (av, i);
2183
2184	/ binmap is accurate (except for bin 1 == unsorted_chunks) /
2185	if (i >= `2`)
2186	{
2187	unsigned int binbit = get_binmap (av, i);
2188	int empty = last (b) == b;
2189	if (!binbit)
2190	assert (empty);
2191	else if (!empty)
2192	assert (binbit);
2193	}
2194
2195	for (p = last (b); p != b; p = p->bk)
2196	{
2197	/ each chunk claims to be free /
2198	do_check_free_chunk (av, p);
2199	size = chunksize (p);
2200	total += size;
2201	if (i >= `2`)
2202	{
2203	/ chunk belongs in bin /
2204	idx = bin_index (size);
2205	assert (idx == i);
2206	/ lists are sorted /
2207	assert (p->bk == b \|\|
2208	(unsigned long) chunksize (p->bk) >= (unsigned long) chunksize (p));
2209
2210	if (!in_smallbin_range (size))
2211	{
2212	if (p->fd_nextsize != NULL)
2213	{
2214	if (p->fd_nextsize == p)
2215	assert (p->bk_nextsize == p);
2216	else
2217	{
2218	if (p->fd_nextsize == first (b))
2219	assert (chunksize (p) < chunksize (p->fd_nextsize));
2220	else
2221	assert (chunksize (p) > chunksize (p->fd_nextsize));
2222
2223	if (p == first (b))
2224	assert (chunksize (p) > chunksize (p->bk_nextsize));
2225	else
2226	assert (chunksize (p) < chunksize (p->bk_nextsize));
2227	}
2228	}
2229	else
2230	assert (p->bk_nextsize == NULL);
2231	}
2232	}
2233	else if (!in_smallbin_range (size))
2234	assert (p->fd_nextsize == NULL && p->bk_nextsize == NULL);
2235	/ chunk is followed by a legal chain of inuse chunks /
2236	for (q = next_chunk (p);
2237	(q != av->top && inuse (q) &&
2238	(unsigned long) (chunksize (q)) >= MINSIZE);
2239	q = next_chunk (q))
2240	do_check_inuse_chunk (av, q);
2241	}
2242	}
2243
2244	/ top chunk is OK /
2245	check_chunk (av, av->top);
2246	}
2247	#endif
2248
2249
2250	/ ----------------- Support for debugging hooks -------------------- /
2251	#include "hooks.c"
2252
2253
2254	/ ----------- Routines dealing with system allocation -------------- /
2255
2256	/*
2257	sysmalloc handles malloc cases requiring more memory from the system.
2258	On entry, it is assumed that av->top does not have enough
2259	space to service request for nb bytes, thus requiring that av->top
2260	be extended or replaced.
2261	*/
2262
2263	static void *
2264	sysmalloc (INTERNAL_SIZE_T nb, mstate av)
2265	{
2266	mchunkptr old_top; / incoming value of av->top /
2267	INTERNAL_SIZE_T old_size; / its size /
2268	char old_end; /* its end address /
2269
2270	long size; / arg to first MORECORE or mmap call /
2271	char brk; /* return value from MORECORE /
2272
2273	long correction; / arg to 2nd MORECORE call /
2274	char snd_brk; /* 2nd return val /
2275
2276	INTERNAL_SIZE_T front_misalign; / unusable bytes at front of new space /
2277	INTERNAL_SIZE_T end_misalign; / partial page left at end of new space /
2278	char aligned_brk; /* aligned offset into brk /
2279
2280	mchunkptr p; / the allocated/returned chunk /
2281	mchunkptr remainder; / remainder from allocation /
2282	unsigned long remainder_size; / its size /
2283
2284
2285	size_t pagesize = GLRO (dl_pagesize);
2286	bool tried_mmap = false;
2287
2288
2289	/*
2290	If have mmap, and the request size meets the mmap threshold, and
2291	the system supports mmap, and there are few enough currently
2292	allocated mmapped regions, try to directly map this request
2293	rather than expanding top.
2294	*/
2295
2296	if (av == NULL
2297	\|\| ((unsigned long) (nb) >= (unsigned long) (mp_.mmap_threshold)
2298	&& (mp_.n_mmaps < mp_.n_mmaps_max)))
2299	{
2300	char mm; /* return value from mmap call/
2301
2302	try_mmap:
2303	/*
2304	Round up size to nearest page. For mmapped chunks, the overhead
2305	is one SIZE_SZ unit larger than for normal chunks, because there
2306	is no following chunk whose prev_size field could be used.
2307
2308	See the front_misalign handling below, for glibc there is no
2309	need for further alignments unless we have have high alignment.
2310	*/
2311	if (MALLOC_ALIGNMENT == `2` * SIZE_SZ)
2312	size = ALIGN_UP (nb + SIZE_SZ, pagesize);
2313	else
2314	size = ALIGN_UP (nb + SIZE_SZ + MALLOC_ALIGN_MASK, pagesize);
2315	tried_mmap = true;
2316
2317	/ Don't try if size wraps around 0 /
2318	if ((unsigned long) (size) > (unsigned long) (nb))
2319	{
2320	mm = (char *) (MMAP (`0`, size, PROT_READ \| PROT_WRITE, `0`));
2321
2322	if (mm != MAP_FAILED)
2323	{
2324	/*
2325	The offset to the start of the mmapped region is stored
2326	in the prev_size field of the chunk. This allows us to adjust
2327	returned start address to meet alignment requirements here
2328	and in memalign(), and still be able to compute proper
2329	address argument for later munmap in free() and realloc().
2330	*/
2331
2332	if (MALLOC_ALIGNMENT == `2` * SIZE_SZ)
2333	{
2334	/ For glibc, chunk2mem increases the address by 2SIZE_SZ and
2335	MALLOC_ALIGN_MASK is 2SIZE_SZ-1. Each mmap'ed area is page*
2336	aligned and therefore definitely MALLOC_ALIGN_MASK-aligned. /*
2337	assert (((INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK) == `0`);
2338	front_misalign = `0`;
2339	}
2340	else
2341	front_misalign = (INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK;
2342	if (front_misalign > `0`)
2343	{
2344	correction = MALLOC_ALIGNMENT - front_misalign;
2345	p = (mchunkptr) (mm + correction);
2346	set_prev_size (p, correction);
2347	set_head (p, (size - correction) \| IS_MMAPPED);
2348	}
2349	else
2350	{
2351	p = (mchunkptr) mm;
2352	set_prev_size (p, `0`);
2353	set_head (p, size \| IS_MMAPPED);
2354	}
2355
2356	/ update statistics /
2357
2358	int new = atomic_exchange_and_add (&mp_.n_mmaps, `1`) + `1`;
2359	atomic_max (&mp_.max_n_mmaps, new);
2360
2361	unsigned long sum;
2362	sum = atomic_exchange_and_add (&mp_.mmapped_mem, size) + size;
2363	atomic_max (&mp_.max_mmapped_mem, sum);
2364
2365	check_chunk (av, p);
2366
2367	return chunk2mem (p);
2368	}
2369	}
2370	}
2371
2372	/ There are no usable arenas and mmap also failed. /
2373	if (av == NULL)
2374	return `0`;
2375
2376	/ Record incoming configuration of top /
2377
2378	old_top = av->top;
2379	old_size = chunksize (old_top);
2380	old_end = (char *) (chunk_at_offset (old_top, old_size));
2381
2382	brk = snd_brk = (char *) (MORECORE_FAILURE);
2383
2384	/*
2385	If not the first time through, we require old_size to be
2386	at least MINSIZE and to have prev_inuse set.
2387	*/
2388
2389	assert ((old_top == initial_top (av) && old_size == `0`) \|\|
2390	((unsigned long) (old_size) >= MINSIZE &&
2391	prev_inuse (old_top) &&
2392	((unsigned long) old_end & (pagesize - `1`)) == `0`));
2393
2394	/ Precondition: not enough current space to satisfy nb request /
2395	assert ((unsigned long) (old_size) < (unsigned long) (nb + MINSIZE));
2396
2397
2398	if (av != &main_arena)
2399	{
2400	heap_info old_heap, heap;
2401	size_t old_heap_size;
2402
2403	/ First try to extend the current heap. /
2404	old_heap = heap_for_ptr (old_top);
2405	old_heap_size = old_heap->size;
2406	if ((long) (MINSIZE + nb - old_size) > `0`
2407	&& grow_heap (old_heap, MINSIZE + nb - old_size) == `0`)
2408	{
2409	av->system_mem += old_heap->size - old_heap_size;
2410	set_head (old_top, (((char ) old_heap + old_heap->size) - (char* *) old_top)
2411	\| PREV_INUSE);
2412	}
2413	else if ((heap = new_heap (nb + (MINSIZE + sizeof (*heap)), mp_.top_pad)))
2414	{
2415	/ Use a newly allocated heap. /
2416	heap->ar_ptr = av;
2417	heap->prev = old_heap;
2418	av->system_mem += heap->size;
2419	/ Set up the new top. /
2420	top (av) = chunk_at_offset (heap, sizeof (*heap));
2421	set_head (top (av), (heap->size - sizeof (*heap)) \| PREV_INUSE);
2422
2423	/ Setup fencepost and free the old top chunk with a multiple of*
2424	MALLOC_ALIGNMENT in size. /*
2425	/ The fencepost takes at least MINSIZE bytes, because it might*
2426	become the top chunk again later. Note that a footer is set
2427	up, too, although the chunk is marked in use. /*
2428	old_size = (old_size - MINSIZE) & ~MALLOC_ALIGN_MASK;
2429	set_head (chunk_at_offset (old_top, old_size + `2` * SIZE_SZ), `0` \| PREV_INUSE);
2430	if (old_size >= MINSIZE)
2431	{
2432	set_head (chunk_at_offset (old_top, old_size), (`2` * SIZE_SZ) \| PREV_INUSE);
2433	set_foot (chunk_at_offset (old_top, old_size), (`2` * SIZE_SZ));
2434	set_head (old_top, old_size \| PREV_INUSE \| NON_MAIN_ARENA);
2435	_int_free (av, old_top, `1`);
2436	}
2437	else
2438	{
2439	set_head (old_top, (old_size + `2` * SIZE_SZ) \| PREV_INUSE);
2440	set_foot (old_top, (old_size + `2` * SIZE_SZ));
2441	}
2442	}
2443	else if (!tried_mmap)
2444	/ We can at least try to use to mmap memory. /
2445	goto try_mmap;
2446	}
2447	else / av == main_arena /
2448
2449
2450	{ / Request enough space for nb + pad + overhead /
2451	size = nb + mp_.top_pad + MINSIZE;
2452
2453	/*
2454	If contiguous, we can subtract out existing space that we hope to
2455	combine with new space. We add it back later only if
2456	we don't actually get contiguous space.
2457	*/
2458
2459	if (contiguous (av))
2460	size -= old_size;
2461
2462	/*
2463	Round to a multiple of page size.
2464	If MORECORE is not contiguous, this ensures that we only call it
2465	with whole-page arguments. And if MORECORE is contiguous and
2466	this is not first time through, this preserves page-alignment of
2467	previous calls. Otherwise, we correct to page-align below.
2468	*/
2469
2470	size = ALIGN_UP (size, pagesize);
2471
2472	/*
2473	Don't try to call MORECORE if argument is so big as to appear
2474	negative. Note that since mmap takes size_t arg, it may succeed
2475	below even if we cannot call MORECORE.
2476	*/
2477
2478	if (size > `0`)
2479	{
2480	brk = (char *) (MORECORE (size));
2481	LIBC_PROBE (memory_sbrk_more, `2`, brk, size);
2482	}
2483
2484	if (brk != (char *) (MORECORE_FAILURE))
2485	{
2486	/ Call the `morecore' hook if necessary. /
2487	void (hook) (void*) = atomic_forced_read (__after_morecore_hook);
2488	if (__builtin_expect (hook != NULL, `0`))
2489	(*hook)();
2490	}
2491	else
2492	{
2493	/*
2494	If have mmap, try using it as a backup when MORECORE fails or
2495	cannot be used. This is worth doing on systems that have "holes" in
2496	address space, so sbrk cannot extend to give contiguous space, but
2497	space is available elsewhere. Note that we ignore mmap max count
2498	and threshold limits, since the space will not be used as a
2499	segregated mmap region.
2500	*/
2501
2502	/ Cannot merge with old top, so add its size back in /
2503	if (contiguous (av))
2504	size = ALIGN_UP (size + old_size, pagesize);
2505
2506	/ If we are relying on mmap as backup, then use larger units /
2507	if ((unsigned long) (size) < (unsigned long) (MMAP_AS_MORECORE_SIZE))
2508	size = MMAP_AS_MORECORE_SIZE;
2509
2510	/ Don't try if size wraps around 0 /
2511	if ((unsigned long) (size) > (unsigned long) (nb))
2512	{
2513	char mbrk = (char* *) (MMAP (`0`, size, PROT_READ \| PROT_WRITE, `0`));
2514
2515	if (mbrk != MAP_FAILED)
2516	{
2517	/ We do not need, and cannot use, another sbrk call to find end /
2518	brk = mbrk;
2519	snd_brk = brk + size;
2520
2521	/*
2522	Record that we no longer have a contiguous sbrk region.
2523	After the first time mmap is used as backup, we do not
2524	ever rely on contiguous space since this could incorrectly
2525	bridge regions.
2526	*/
2527	set_noncontiguous (av);
2528	}
2529	}
2530	}
2531
2532	if (brk != (char *) (MORECORE_FAILURE))
2533	{
2534	if (mp_.sbrk_base == `0`)
2535	mp_.sbrk_base = brk;
2536	av->system_mem += size;
2537
2538	/*
2539	If MORECORE extends previous space, we can likewise extend top size.
2540	*/
2541
2542	if (brk == old_end && snd_brk == (char *) (MORECORE_FAILURE))
2543	set_head (old_top, (size + old_size) \| PREV_INUSE);
2544
2545	else if (contiguous (av) && old_size && brk < old_end)
2546	/ Oops! Someone else killed our space.. Can't touch anything. /
2547	malloc_printerr ("break adjusted to free malloc space");
2548
2549	/*
2550	Otherwise, make adjustments:
2551
2552	* If the first time through or noncontiguous, we need to call sbrk
2553	just to find out where the end of memory lies.
2554
2555	* We need to ensure that all returned chunks from malloc will meet
2556	MALLOC_ALIGNMENT
2557
2558	* If there was an intervening foreign sbrk, we need to adjust sbrk
2559	request size to account for fact that we will not be able to
2560	combine new space with existing space in old_top.
2561
2562	* Almost all systems internally allocate whole pages at a time, in
2563	which case we might as well use the whole last page of request.
2564	So we allocate enough more memory to hit a page boundary now,
2565	which in turn causes future contiguous calls to page-align.
2566	*/
2567
2568	else
2569	{
2570	front_misalign = `0`;
2571	end_misalign = `0`;
2572	correction = `0`;
2573	aligned_brk = brk;
2574
2575	/ handle contiguous cases /
2576	if (contiguous (av))
2577	{
2578	/ Count foreign sbrk as system_mem. /
2579	if (old_size)
2580	av->system_mem += brk - old_end;
2581
2582	/ Guarantee alignment of first new chunk made from this space /
2583
2584	front_misalign = (INTERNAL_SIZE_T) chunk2mem (brk) & MALLOC_ALIGN_MASK;
2585	if (front_misalign > `0`)
2586	{
2587	/*
2588	Skip over some bytes to arrive at an aligned position.
2589	We don't need to specially mark these wasted front bytes.
2590	They will never be accessed anyway because
2591	prev_inuse of av->top (and any chunk created from its start)
2592	is always true after initialization.
2593	*/
2594
2595	correction = MALLOC_ALIGNMENT - front_misalign;
2596	aligned_brk += correction;
2597	}
2598
2599	/*
2600	If this isn't adjacent to existing space, then we will not
2601	be able to merge with old_top space, so must add to 2nd request.
2602	*/
2603
2604	correction += old_size;
2605
2606	/ Extend the end address to hit a page boundary /
2607	end_misalign = (INTERNAL_SIZE_T) (brk + size + correction);
2608	correction += (ALIGN_UP (end_misalign, pagesize)) - end_misalign;
2609
2610	assert (correction >= `0`);
2611	snd_brk = (char *) (MORECORE (correction));
2612
2613	/*
2614	If can't allocate correction, try to at least find out current
2615	brk. It might be enough to proceed without failing.
2616
2617	Note that if second sbrk did NOT fail, we assume that space
2618	is contiguous with first sbrk. This is a safe assumption unless
2619	program is multithreaded but doesn't use locks and a foreign sbrk
2620	occurred between our first and second calls.
2621	*/
2622
2623	if (snd_brk == (char *) (MORECORE_FAILURE))
2624	{
2625	correction = `0`;
2626	snd_brk = (char *) (MORECORE (`0`));
2627	}
2628	else
2629	{
2630	/ Call the `morecore' hook if necessary. /
2631	void (hook) (void*) = atomic_forced_read (__after_morecore_hook);
2632	if (__builtin_expect (hook != NULL, `0`))
2633	(*hook)();
2634	}
2635	}
2636
2637	/ handle non-contiguous cases /
2638	else
2639	{
2640	if (MALLOC_ALIGNMENT == `2` * SIZE_SZ)
2641	/ MORECORE/mmap must correctly align /
2642	assert (((unsigned long) chunk2mem (brk) & MALLOC_ALIGN_MASK) == `0`);
2643	else
2644	{
2645	front_misalign = (INTERNAL_SIZE_T) chunk2mem (brk) & MALLOC_ALIGN_MASK;
2646	if (front_misalign > `0`)
2647	{
2648	/*
2649	Skip over some bytes to arrive at an aligned position.
2650	We don't need to specially mark these wasted front bytes.
2651	They will never be accessed anyway because
2652	prev_inuse of av->top (and any chunk created from its start)
2653	is always true after initialization.
2654	*/
2655
2656	aligned_brk += MALLOC_ALIGNMENT - front_misalign;
2657	}
2658	}
2659
2660	/ Find out current end of memory /
2661	if (snd_brk == (char *) (MORECORE_FAILURE))
2662	{
2663	snd_brk = (char *) (MORECORE (`0`));
2664	}
2665	}
2666
2667	/ Adjust top based on results of second sbrk /
2668	if (snd_brk != (char *) (MORECORE_FAILURE))
2669	{
2670	av->top = (mchunkptr) aligned_brk;
2671	set_head (av->top, (snd_brk - aligned_brk + correction) \| PREV_INUSE);
2672	av->system_mem += correction;
2673
2674	/*
2675	If not the first time through, we either have a
2676	gap due to foreign sbrk or a non-contiguous region. Insert a
2677	double fencepost at old_top to prevent consolidation with space
2678	we don't own. These fenceposts are artificial chunks that are
2679	marked as inuse and are in any case too small to use. We need
2680	two to make sizes and alignments work out.
2681	*/
2682
2683	if (old_size != `0`)
2684	{
2685	/*
2686	Shrink old_top to insert fenceposts, keeping size a
2687	multiple of MALLOC_ALIGNMENT. We know there is at least
2688	enough space in old_top to do this.
2689	*/
2690	old_size = (old_size - `4` * SIZE_SZ) & ~MALLOC_ALIGN_MASK;
2691	set_head (old_top, old_size \| PREV_INUSE);
2692
2693	/*
2694	Note that the following assignments completely overwrite
2695	old_top when old_size was previously MINSIZE. This is
2696	intentional. We need the fencepost, even if old_top otherwise gets
2697	lost.
2698	*/
2699	set_head (chunk_at_offset (old_top, old_size),
2700	(`2` * SIZE_SZ) \| PREV_INUSE);
2701	set_head (chunk_at_offset (old_top, old_size + `2` * SIZE_SZ),
2702	(`2` * SIZE_SZ) \| PREV_INUSE);
2703
2704	/ If possible, release the rest. /
2705	if (old_size >= MINSIZE)
2706	{
2707	_int_free (av, old_top, `1`);
2708	}
2709	}
2710	}
2711	}
2712	}
2713	} / if (av != &main_arena) /
2714
2715	if ((unsigned long) av->system_mem > (unsigned long) (av->max_system_mem))
2716	av->max_system_mem = av->system_mem;
2717	check_malloc_state (av);
2718
2719	/ finally, do the allocation /
2720	p = av->top;
2721	size = chunksize (p);
2722
2723	/ check that one of the above allocation paths succeeded /
2724	if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
2725	{
2726	remainder_size = size - nb;
2727	remainder = chunk_at_offset (p, nb);
2728	av->top = remainder;
2729	set_head (p, nb \| PREV_INUSE \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
2730	set_head (remainder, remainder_size \| PREV_INUSE);
2731	check_malloced_chunk (av, p, nb);
2732	return chunk2mem (p);
2733	}
2734
2735	/ catch all failure paths /
2736	__set_errno (ENOMEM);
2737	return `0`;
2738	}
2739
2740
2741	/*
2742	systrim is an inverse of sorts to sysmalloc. It gives memory back
2743	to the system (via negative arguments to sbrk) if there is unused
2744	memory at the `high' end of the malloc pool. It is called
2745	automatically by free() when top space exceeds the trim
2746	threshold. It is also called by the public malloc_trim routine. It
2747	returns 1 if it actually released any memory, else 0.
2748	*/
2749
2750	static int
2751	systrim (size_t pad, mstate av)
2752	{
2753	long top_size; / Amount of top-most memory /
2754	long extra; / Amount to release /
2755	long released; / Amount actually released /
2756	char current_brk; /* address returned by pre-check sbrk call /
2757	char new_brk; /* address returned by post-check sbrk call /
2758	size_t pagesize;
2759	long top_area;
2760
2761	pagesize = GLRO (dl_pagesize);
2762	top_size = chunksize (av->top);
2763
2764	top_area = top_size - MINSIZE - `1`;
2765	if (top_area <= pad)
2766	return `0`;
2767
2768	/ Release in pagesize units and round down to the nearest page. /
2769	extra = ALIGN_DOWN(top_area - pad, pagesize);
2770
2771	if (extra == `0`)
2772	return `0`;
2773
2774	/*
2775	Only proceed if end of memory is where we last set it.
2776	This avoids problems if there were foreign sbrk calls.
2777	*/
2778	current_brk = (char *) (MORECORE (`0`));
2779	if (current_brk == (char *) (av->top) + top_size)
2780	{
2781	/*
2782	Attempt to release memory. We ignore MORECORE return value,
2783	and instead call again to find out where new end of memory is.
2784	This avoids problems if first call releases less than we asked,
2785	of if failure somehow altered brk value. (We could still
2786	encounter problems if it altered brk in some very bad way,
2787	but the only thing we can do is adjust anyway, which will cause
2788	some downstream failure.)
2789	*/
2790
2791	MORECORE (-extra);
2792	/ Call the `morecore' hook if necessary. /
2793	void (hook) (void*) = atomic_forced_read (__after_morecore_hook);
2794	if (__builtin_expect (hook != NULL, `0`))
2795	(*hook)();
2796	new_brk = (char *) (MORECORE (`0`));
2797
2798	LIBC_PROBE (memory_sbrk_less, `2`, new_brk, extra);
2799
2800	if (new_brk != (char *) MORECORE_FAILURE)
2801	{
2802	released = (long) (current_brk - new_brk);
2803
2804	if (released != `0`)
2805	{
2806	/ Success. Adjust top. /
2807	av->system_mem -= released;
2808	set_head (av->top, (top_size - released) \| PREV_INUSE);
2809	check_malloc_state (av);
2810	return `1`;
2811	}
2812	}
2813	}
2814	return `0`;
2815	}
2816
2817	static void
2818	munmap_chunk (mchunkptr p)
2819	{
2820	size_t pagesize = GLRO (dl_pagesize);
2821	INTERNAL_SIZE_T size = chunksize (p);
2822
2823	assert (chunk_is_mmapped (p));
2824
2825	/ Do nothing if the chunk is a faked mmapped chunk in the dumped*
2826	main arena. We never free this memory. /*
2827	if (DUMPED_MAIN_ARENA_CHUNK (p))
2828	return;
2829
2830	uintptr_t mem = (uintptr_t) chunk2mem (p);
2831	uintptr_t block = (uintptr_t) p - prev_size (p);
2832	size_t total_size = prev_size (p) + size;
2833	/ Unfortunately we have to do the compilers job by hand here. Normally*
2834	we would test BLOCK and TOTAL-SIZE separately for compliance with the
2835	page size. But gcc does not recognize the optimization possibility
2836	(in the moment at least) so we combine the two values into one before
2837	the bit test. /*
2838	if (__glibc_unlikely ((block \| total_size) & (pagesize - `1`)) != `0`
2839	\|\| __glibc_unlikely (!powerof2 (mem & (pagesize - `1`))))
2840	malloc_printerr ("munmap_chunk(): invalid pointer");
2841
2842	atomic_decrement (&mp_.n_mmaps);
2843	atomic_add (&mp_.mmapped_mem, -total_size);
2844
2845	/ If munmap failed the process virtual memory address space is in a*
2846	bad shape. Just leave the block hanging around, the process will
2847	terminate shortly anyway since not much can be done. /*
2848	__munmap ((char *) block, total_size);
2849	}
2850
2851	#if HAVE_MREMAP
2852
2853	static mchunkptr
2854	mremap_chunk (mchunkptr p, size_t new_size)
2855	{
2856	size_t pagesize = GLRO (dl_pagesize);
2857	INTERNAL_SIZE_T offset = prev_size (p);
2858	INTERNAL_SIZE_T size = chunksize (p);
2859	char *cp;
2860
2861	assert (chunk_is_mmapped (p));
2862
2863	uintptr_t block = (uintptr_t) p - offset;
2864	uintptr_t mem = (uintptr_t) chunk2mem(p);
2865	size_t total_size = offset + size;
2866	if (__glibc_unlikely ((block \| total_size) & (pagesize - `1`)) != `0`
2867	\|\| __glibc_unlikely (!powerof2 (mem & (pagesize - `1`))))
2868	malloc_printerr("mremap_chunk(): invalid pointer");
2869
2870	/ Note the extra SIZE_SZ overhead as in mmap_chunk(). /
2871	new_size = ALIGN_UP (new_size + offset + SIZE_SZ, pagesize);
2872
2873	/ No need to remap if the number of pages does not change. /
2874	if (total_size == new_size)
2875	return p;
2876
2877	cp = (char ) __mremap ((char* *) block, total_size, new_size,
2878	MREMAP_MAYMOVE);
2879
2880	if (cp == MAP_FAILED)
2881	return `0`;
2882
2883	p = (mchunkptr) (cp + offset);
2884
2885	assert (aligned_OK (chunk2mem (p)));
2886
2887	assert (prev_size (p) == offset);
2888	set_head (p, (new_size - offset) \| IS_MMAPPED);
2889
2890	INTERNAL_SIZE_T new;
2891	new = atomic_exchange_and_add (&mp_.mmapped_mem, new_size - size - offset)
2892	+ new_size - size - offset;
2893	atomic_max (&mp_.max_mmapped_mem, new);
2894	return p;
2895	}
2896	#endif /* HAVE_MREMAP */
2897
2898	/------------------------ Public wrappers. --------------------------------/
2899
2900	#if USE_TCACHE
2901
2902	/ We overlay this structure on the user-data portion of a chunk when*
2903	the chunk is stored in the per-thread cache. /*
2904	typedef struct tcache_entry
2905	{
2906	struct tcache_entry *next;
2907	/ This field exists to detect double frees. /
2908	struct tcache_perthread_struct *key;
2909	} tcache_entry;
2910
2911	/ There is one of these for each thread, which contains the*
2912	per-thread cache (hence "tcache_perthread_struct"). Keeping
2913	overall size low is mildly important. Note that COUNTS and ENTRIES
2914	are redundant (we could have just counted the linked list each
2915	time), this is for performance reasons. /*
2916	typedef struct tcache_perthread_struct
2917	{
2918	char counts[TCACHE_MAX_BINS];
2919	tcache_entry *entries[TCACHE_MAX_BINS];
2920	} tcache_perthread_struct;
2921
2922	static __thread bool tcache_shutting_down = false;
2923	static __thread tcache_perthread_struct *tcache = NULL;
2924
2925	/ Caller must ensure that we know tc_idx is valid and there's room*
2926	for more chunks. /*
2927	static __always_inline void
2928	tcache_put (mchunkptr chunk, size_t tc_idx)
2929	{
2930	tcache_entry e = (tcache_entry ) chunk2mem (chunk);
2931	assert (tc_idx < TCACHE_MAX_BINS);
2932
2933	/ Mark this chunk as "in the tcache" so the test in _int_free will*
2934	detect a double free. /*
2935	e->key = tcache;
2936
2937	e->next = tcache->entries[tc_idx];
2938	tcache->entries[tc_idx] = e;
2939	++(tcache->counts[tc_idx]);
2940	}
2941
2942	/ Caller must ensure that we know tc_idx is valid and there's*
2943	available chunks to remove. /*
2944	static __always_inline void *
2945	tcache_get (size_t tc_idx)
2946	{
2947	tcache_entry *e = tcache->entries[tc_idx];
2948	assert (tc_idx < TCACHE_MAX_BINS);
2949	assert (tcache->entries[tc_idx] > `0`);
2950	tcache->entries[tc_idx] = e->next;
2951	--(tcache->counts[tc_idx]);
2952	e->key = NULL;
2953	return (void *) e;
2954	}
2955
2956	static void
2957	tcache_thread_shutdown (void)
2958	{
2959	int i;
2960	tcache_perthread_struct *tcache_tmp = tcache;
2961
2962	if (!tcache)
2963	return;
2964
2965	/ Disable the tcache and prevent it from being reinitialized. /
2966	tcache = NULL;
2967	tcache_shutting_down = true;
2968
2969	/ Free all of the entries and the tcache itself back to the arena*
2970	heap for coalescing. /*
2971	for (i = `0`; i < TCACHE_MAX_BINS; ++i)
2972	{
2973	while (tcache_tmp->entries[i])
2974	{
2975	tcache_entry *e = tcache_tmp->entries[i];
2976	tcache_tmp->entries[i] = e->next;
2977	__libc_free (e);
2978	}
2979	}
2980
2981	__libc_free (tcache_tmp);
2982	}
2983
2984	static void
2985	tcache_init(void)
2986	{
2987	mstate ar_ptr;
2988	void *victim = `0`;
2989	const size_t bytes = sizeof (tcache_perthread_struct);
2990
2991	if (tcache_shutting_down)
2992	return;
2993
2994	arena_get (ar_ptr, bytes);
2995	victim = _int_malloc (ar_ptr, bytes);
2996	if (!victim && ar_ptr != NULL)
2997	{
2998	ar_ptr = arena_get_retry (ar_ptr, bytes);
2999	victim = _int_malloc (ar_ptr, bytes);
3000	}
3001
3002
3003	if (ar_ptr != NULL)
3004	__libc_lock_unlock (ar_ptr->mutex);
3005
3006	/ In a low memory situation, we may not be able to allocate memory*
3007	- in which case, we just keep trying later. However, we
3008	typically do this very early, so either there is sufficient
3009	memory, or there isn't enough memory to do non-trivial
3010	allocations anyway. /*
3011	if (victim)
3012	{
3013	tcache = (tcache_perthread_struct *) victim;
3014	memset (tcache, `0`, sizeof (tcache_perthread_struct));
3015	}
3016
3017	}
3018
3019	# define MAYBE_INIT_TCACHE() \
3020	if (__glibc_unlikely (tcache == NULL)) \
3021	tcache_init();
3022
3023	#else /* !USE_TCACHE */
3024	# define MAYBE_INIT_TCACHE()
3025
3026	static void
3027	tcache_thread_shutdown (void)
3028	{
3029	/ Nothing to do if there is no thread cache. /
3030	}
3031
3032	#endif /* !USE_TCACHE */
3033
3034	void *
3035	__libc_malloc (size_t bytes)
3036	{
3037	mstate ar_ptr;
3038	void *victim;
3039
3040	void (hook) (size_t, const void *)
3041	= atomic_forced_read (__malloc_hook);
3042	if (__builtin_expect (hook != NULL, `0`))
3043	return (*hook)(bytes, RETURN_ADDRESS (`0`));
3044	#if USE_TCACHE
3045	/ int_free also calls request2size, be careful to not pad twice. /
3046	size_t tbytes;
3047	checked_request2size (bytes, tbytes);
3048	size_t tc_idx = csize2tidx (tbytes);
3049
3050	MAYBE_INIT_TCACHE ();
3051
3052	DIAG_PUSH_NEEDS_COMMENT;
3053	if (tc_idx < mp_.tcache_bins
3054	/&& tc_idx < TCACHE_MAX_BINS/ / to appease gcc /
3055	&& tcache
3056	&& tcache->entries[tc_idx] != NULL)
3057	{
3058	return tcache_get (tc_idx);
3059	}
3060	DIAG_POP_NEEDS_COMMENT;
3061	#endif
3062
3063	if (SINGLE_THREAD_P)
3064	{
3065	victim = _int_malloc (&main_arena, bytes);
3066	assert (!victim \|\| chunk_is_mmapped (mem2chunk (victim)) \|\|
3067	&main_arena == arena_for_chunk (mem2chunk (victim)));
3068	return victim;
3069	}
3070
3071	arena_get (ar_ptr, bytes);
3072
3073	victim = _int_malloc (ar_ptr, bytes);
3074	/ Retry with another arena only if we were able to find a usable arena*
3075	before. /*
3076	if (!victim && ar_ptr != NULL)
3077	{
3078	LIBC_PROBE (memory_malloc_retry, `1`, bytes);
3079	ar_ptr = arena_get_retry (ar_ptr, bytes);
3080	victim = _int_malloc (ar_ptr, bytes);
3081	}
3082
3083	if (ar_ptr != NULL)
3084	__libc_lock_unlock (ar_ptr->mutex);
3085
3086	assert (!victim \|\| chunk_is_mmapped (mem2chunk (victim)) \|\|
3087	ar_ptr == arena_for_chunk (mem2chunk (victim)));
3088	return victim;
3089	}
3090	libc_hidden_def (__libc_malloc)
3091
3092	void
3093	__libc_free (void *mem)
3094	{
3095	mstate ar_ptr;
3096	mchunkptr p; / chunk corresponding to mem /
3097
3098	void (hook) (void* , const* void *)
3099	= atomic_forced_read (__free_hook);
3100	if (__builtin_expect (hook != NULL, `0`))
3101	{
3102	(*hook)(mem, RETURN_ADDRESS (`0`));
3103	return;
3104	}
3105
3106	if (mem == `0`) / free(0) has no effect /
3107	return;
3108
3109	p = mem2chunk (mem);
3110
3111	if (chunk_is_mmapped (p)) / release mmapped memory. /
3112	{
3113	/ See if the dynamic brk/mmap threshold needs adjusting.*
3114	Dumped fake mmapped chunks do not affect the threshold. /*
3115	if (!mp_.no_dyn_threshold
3116	&& chunksize_nomask (p) > mp_.mmap_threshold
3117	&& chunksize_nomask (p) <= DEFAULT_MMAP_THRESHOLD_MAX
3118	&& !DUMPED_MAIN_ARENA_CHUNK (p))
3119	{
3120	mp_.mmap_threshold = chunksize (p);
3121	mp_.trim_threshold = `2` * mp_.mmap_threshold;
3122	LIBC_PROBE (memory_mallopt_free_dyn_thresholds, `2`,
3123	mp_.mmap_threshold, mp_.trim_threshold);
3124	}
3125	munmap_chunk (p);
3126	return;
3127	}
3128
3129	MAYBE_INIT_TCACHE ();
3130
3131	ar_ptr = arena_for_chunk (p);
3132	_int_free (ar_ptr, p, `0`);
3133	}
3134	libc_hidden_def (__libc_free)
3135
3136	void *
3137	__libc_realloc (void *oldmem, size_t bytes)
3138	{
3139	mstate ar_ptr;
3140	INTERNAL_SIZE_T nb; / padded request size /
3141
3142	void newp; /* chunk to return /
3143
3144	void (hook) (void , size_t, const* void *) =
3145	atomic_forced_read (__realloc_hook);
3146	if (__builtin_expect (hook != NULL, `0`))
3147	return (*hook)(oldmem, bytes, RETURN_ADDRESS (`0`));
3148
3149	#if REALLOC_ZERO_BYTES_FREES
3150	if (bytes == `0` && oldmem != NULL)
3151	{
3152	__libc_free (oldmem); return `0`;
3153	}
3154	#endif
3155
3156	/ realloc of null is supposed to be same as malloc /
3157	if (oldmem == `0`)
3158	return __libc_malloc (bytes);
3159
3160	/ chunk corresponding to oldmem /
3161	const mchunkptr oldp = mem2chunk (oldmem);
3162	/ its size /
3163	const INTERNAL_SIZE_T oldsize = chunksize (oldp);
3164
3165	if (chunk_is_mmapped (oldp))
3166	ar_ptr = NULL;
3167	else
3168	{
3169	MAYBE_INIT_TCACHE ();
3170	ar_ptr = arena_for_chunk (oldp);
3171	}
3172
3173	/ Little security check which won't hurt performance: the allocator*
3174	never wrapps around at the end of the address space. Therefore
3175	we can exclude some size values which might appear here by
3176	accident or by "design" from some intruder. We need to bypass
3177	this check for dumped fake mmap chunks from the old main arena
3178	because the new malloc may provide additional alignment. /*
3179	if ((__builtin_expect ((uintptr_t) oldp > (uintptr_t) -oldsize, `0`)
3180	\|\| __builtin_expect (misaligned_chunk (oldp), `0`))
3181	&& !DUMPED_MAIN_ARENA_CHUNK (oldp))
3182	malloc_printerr ("realloc(): invalid pointer");
3183
3184	checked_request2size (bytes, nb);
3185
3186	if (chunk_is_mmapped (oldp))
3187	{
3188	/ If this is a faked mmapped chunk from the dumped main arena,*
3189	always make a copy (and do not free the old chunk). /*
3190	if (DUMPED_MAIN_ARENA_CHUNK (oldp))
3191	{
3192	/ Must alloc, copy, free. /
3193	void *newmem = __libc_malloc (bytes);
3194	if (newmem == `0`)
3195	return NULL;
3196	/ Copy as many bytes as are available from the old chunk*
3197	and fit into the new size. NB: The overhead for faked
3198	mmapped chunks is only SIZE_SZ, not 2 SIZE_SZ as for*
3199	regular mmapped chunks. /*
3200	if (bytes > oldsize - SIZE_SZ)
3201	bytes = oldsize - SIZE_SZ;
3202	memcpy (newmem, oldmem, bytes);
3203	return newmem;
3204	}
3205
3206	void *newmem;
3207
3208	#if HAVE_MREMAP
3209	newp = mremap_chunk (oldp, nb);
3210	if (newp)
3211	return chunk2mem (newp);
3212	#endif
3213	/ Note the extra SIZE_SZ overhead. /
3214	if (oldsize - SIZE_SZ >= nb)
3215	return oldmem; / do nothing /
3216
3217	/ Must alloc, copy, free. /
3218	newmem = __libc_malloc (bytes);
3219	if (newmem == `0`)
3220	return `0`; / propagate failure /
3221
3222	memcpy (newmem, oldmem, oldsize - `2` * SIZE_SZ);
3223	munmap_chunk (oldp);
3224	return newmem;
3225	}
3226
3227	if (SINGLE_THREAD_P)
3228	{
3229	newp = _int_realloc (ar_ptr, oldp, oldsize, nb);
3230	assert (!newp \|\| chunk_is_mmapped (mem2chunk (newp)) \|\|
3231	ar_ptr == arena_for_chunk (mem2chunk (newp)));
3232
3233	return newp;
3234	}
3235
3236	__libc_lock_lock (ar_ptr->mutex);
3237
3238	newp = _int_realloc (ar_ptr, oldp, oldsize, nb);
3239
3240	__libc_lock_unlock (ar_ptr->mutex);
3241	assert (!newp \|\| chunk_is_mmapped (mem2chunk (newp)) \|\|
3242	ar_ptr == arena_for_chunk (mem2chunk (newp)));
3243
3244	if (newp == NULL)
3245	{
3246	/ Try harder to allocate memory in other arenas. /
3247	LIBC_PROBE (memory_realloc_retry, `2`, bytes, oldmem);
3248	newp = __libc_malloc (bytes);
3249	if (newp != NULL)
3250	{
3251	memcpy (newp, oldmem, oldsize - SIZE_SZ);
3252	_int_free (ar_ptr, oldp, `0`);
3253	}
3254	}
3255
3256	return newp;
3257	}
3258	libc_hidden_def (__libc_realloc)
3259
3260	void *
3261	__libc_memalign (size_t alignment, size_t bytes)
3262	{
3263	void *address = RETURN_ADDRESS (`0`);
3264	return _mid_memalign (alignment, bytes, address);
3265	}
3266
3267	static void *
3268	_mid_memalign (size_t alignment, size_t bytes, void *address)
3269	{
3270	mstate ar_ptr;
3271	void *p;
3272
3273	void (hook) (size_t, size_t, const void *) =
3274	atomic_forced_read (__memalign_hook);
3275	if (__builtin_expect (hook != NULL, `0`))
3276	return (*hook)(alignment, bytes, address);
3277
3278	/ If we need less alignment than we give anyway, just relay to malloc. /
3279	if (alignment <= MALLOC_ALIGNMENT)
3280	return __libc_malloc (bytes);
3281
3282	/ Otherwise, ensure that it is at least a minimum chunk size /
3283	if (alignment < MINSIZE)
3284	alignment = MINSIZE;
3285
3286	/ If the alignment is greater than SIZE_MAX / 2 + 1 it cannot be a*
3287	power of 2 and will cause overflow in the check below. /*
3288	if (alignment > SIZE_MAX / `2` + `1`)
3289	{
3290	__set_errno (EINVAL);
3291	return `0`;
3292	}
3293
3294	/ Check for overflow. /
3295	if (bytes > SIZE_MAX - alignment - MINSIZE)
3296	{
3297	__set_errno (ENOMEM);
3298	return `0`;
3299	}
3300
3301
3302	/ Make sure alignment is power of 2. /
3303	if (!powerof2 (alignment))
3304	{
3305	size_t a = MALLOC_ALIGNMENT * `2`;
3306	while (a < alignment)
3307	a <<= `1`;
3308	alignment = a;
3309	}
3310
3311	if (SINGLE_THREAD_P)
3312	{
3313	p = _int_memalign (&main_arena, alignment, bytes);
3314	assert (!p \|\| chunk_is_mmapped (mem2chunk (p)) \|\|
3315	&main_arena == arena_for_chunk (mem2chunk (p)));
3316
3317	return p;
3318	}
3319
3320	arena_get (ar_ptr, bytes + alignment + MINSIZE);
3321
3322	p = _int_memalign (ar_ptr, alignment, bytes);
3323	if (!p && ar_ptr != NULL)
3324	{
3325	LIBC_PROBE (memory_memalign_retry, `2`, bytes, alignment);
3326	ar_ptr = arena_get_retry (ar_ptr, bytes);
3327	p = _int_memalign (ar_ptr, alignment, bytes);
3328	}
3329
3330	if (ar_ptr != NULL)
3331	__libc_lock_unlock (ar_ptr->mutex);
3332
3333	assert (!p \|\| chunk_is_mmapped (mem2chunk (p)) \|\|
3334	ar_ptr == arena_for_chunk (mem2chunk (p)));
3335	return p;
3336	}
3337	/ For ISO C11. /
3338	weak_alias (__libc_memalign, aligned_alloc)
3339	libc_hidden_def (__libc_memalign)
3340
3341	void *
3342	__libc_valloc (size_t bytes)
3343	{
3344	if (__malloc_initialized < `0`)
3345	ptmalloc_init ();
3346
3347	void *address = RETURN_ADDRESS (`0`);
3348	size_t pagesize = GLRO (dl_pagesize);
3349	return _mid_memalign (pagesize, bytes, address);
3350	}
3351
3352	void *
3353	__libc_pvalloc (size_t bytes)
3354	{
3355	if (__malloc_initialized < `0`)
3356	ptmalloc_init ();
3357
3358	void *address = RETURN_ADDRESS (`0`);
3359	size_t pagesize = GLRO (dl_pagesize);
3360	size_t rounded_bytes = ALIGN_UP (bytes, pagesize);
3361
3362	/ Check for overflow. /
3363	if (bytes > SIZE_MAX - `2` * pagesize - MINSIZE)
3364	{
3365	__set_errno (ENOMEM);
3366	return `0`;
3367	}
3368
3369	return _mid_memalign (pagesize, rounded_bytes, address);
3370	}
3371
3372	void *
3373	__libc_calloc (size_t n, size_t elem_size)
3374	{
3375	mstate av;
3376	mchunkptr oldtop, p;
3377	INTERNAL_SIZE_T bytes, sz, csz, oldtopsize;
3378	void *mem;
3379	unsigned long clearsize;
3380	unsigned long nclears;
3381	INTERNAL_SIZE_T *d;
3382
3383	/ size_t is unsigned so the behavior on overflow is defined. /
3384	bytes = n * elem_size;
3385	#define HALF_INTERNAL_SIZE_T \
3386	(((INTERNAL_SIZE_T) 1) << (8 * sizeof (INTERNAL_SIZE_T) / 2))
3387	if (__builtin_expect ((n \| elem_size) >= HALF_INTERNAL_SIZE_T, `0`))
3388	{
3389	if (elem_size != `0` && bytes / elem_size != n)
3390	{
3391	__set_errno (ENOMEM);
3392	return `0`;
3393	}
3394	}
3395
3396	void (hook) (size_t, const void *) =
3397	atomic_forced_read (__malloc_hook);
3398	if (__builtin_expect (hook != NULL, `0`))
3399	{
3400	sz = bytes;
3401	mem = (*hook)(sz, RETURN_ADDRESS (`0`));
3402	if (mem == `0`)
3403	return `0`;
3404
3405	return memset (mem, `0`, sz);
3406	}
3407
3408	sz = bytes;
3409
3410	MAYBE_INIT_TCACHE ();
3411
3412	if (SINGLE_THREAD_P)
3413	av = &main_arena;
3414	else
3415	arena_get (av, sz);
3416
3417	if (av)
3418	{
3419	/ Check if we hand out the top chunk, in which case there may be no*
3420	need to clear. /*
3421	#if MORECORE_CLEARS
3422	oldtop = top (av);
3423	oldtopsize = chunksize (top (av));
3424	# if MORECORE_CLEARS < 2
3425	/ Only newly allocated memory is guaranteed to be cleared. /
3426	if (av == &main_arena &&
3427	oldtopsize < mp_.sbrk_base + av->max_system_mem - (char *) oldtop)
3428	oldtopsize = (mp_.sbrk_base + av->max_system_mem - (char *) oldtop);
3429	# endif
3430	if (av != &main_arena)
3431	{
3432	heap_info *heap = heap_for_ptr (oldtop);
3433	if (oldtopsize < (char ) heap + heap->mprotect_size - (char* *) oldtop)
3434	oldtopsize = (char ) heap + heap->mprotect_size - (char* *) oldtop;
3435	}
3436	#endif
3437	}
3438	else
3439	{
3440	/ No usable arenas. /
3441	oldtop = `0`;
3442	oldtopsize = `0`;
3443	}
3444	mem = _int_malloc (av, sz);
3445
3446	assert (!mem \|\| chunk_is_mmapped (mem2chunk (mem)) \|\|
3447	av == arena_for_chunk (mem2chunk (mem)));
3448
3449	if (!SINGLE_THREAD_P)
3450	{
3451	if (mem == `0` && av != NULL)
3452	{
3453	LIBC_PROBE (memory_calloc_retry, `1`, sz);
3454	av = arena_get_retry (av, sz);
3455	mem = _int_malloc (av, sz);
3456	}
3457
3458	if (av != NULL)
3459	__libc_lock_unlock (av->mutex);
3460	}
3461
3462	/ Allocation failed even after a retry. /
3463	if (mem == `0`)
3464	return `0`;
3465
3466	p = mem2chunk (mem);
3467
3468	/ Two optional cases in which clearing not necessary /
3469	if (chunk_is_mmapped (p))
3470	{
3471	if (__builtin_expect (perturb_byte, `0`))
3472	return memset (mem, `0`, sz);
3473
3474	return mem;
3475	}
3476
3477	csz = chunksize (p);
3478
3479	#if MORECORE_CLEARS
3480	if (perturb_byte == `0` && (p == oldtop && csz > oldtopsize))
3481	{
3482	/ clear only the bytes from non-freshly-sbrked memory /
3483	csz = oldtopsize;
3484	}
3485	#endif
3486
3487	/ Unroll clear of <= 36 bytes (72 if 8byte sizes). We know that*
3488	contents have an odd number of INTERNAL_SIZE_T-sized words;
3489	minimally 3. /*
3490	d = (INTERNAL_SIZE_T *) mem;
3491	clearsize = csz - SIZE_SZ;
3492	nclears = clearsize / sizeof (INTERNAL_SIZE_T);
3493	assert (nclears >= `3`);
3494
3495	if (nclears > `9`)
3496	return memset (d, `0`, clearsize);
3497
3498	else
3499	{
3500	*(d + `0`) = `0`;
3501	*(d + `1`) = `0`;
3502	*(d + `2`) = `0`;
3503	if (nclears > `4`)
3504	{
3505	*(d + `3`) = `0`;
3506	*(d + `4`) = `0`;
3507	if (nclears > `6`)
3508	{
3509	*(d + `5`) = `0`;
3510	*(d + `6`) = `0`;
3511	if (nclears > `8`)
3512	{
3513	*(d + `7`) = `0`;
3514	*(d + `8`) = `0`;
3515	}
3516	}
3517	}
3518	}
3519
3520	return mem;
3521	}
3522
3523	/*
3524	------------------------------ malloc ------------------------------
3525	*/
3526
3527	static void *
3528	_int_malloc (mstate av, size_t bytes)
3529	{
3530	INTERNAL_SIZE_T nb; / normalized request size /
3531	unsigned int idx; / associated bin index /
3532	mbinptr bin; / associated bin /
3533
3534	mchunkptr victim; / inspected/selected chunk /
3535	INTERNAL_SIZE_T size; / its size /
3536	int victim_index; / its bin index /
3537
3538	mchunkptr remainder; / remainder from a split /
3539	unsigned long remainder_size; / its size /
3540
3541	unsigned int block; / bit map traverser /
3542	unsigned int bit; / bit map traverser /
3543	unsigned int map; / current word of binmap /
3544
3545	mchunkptr fwd; / misc temp for linking /
3546	mchunkptr bck; / misc temp for linking /
3547
3548	#if USE_TCACHE
3549	size_t tcache_unsorted_count; / count of unsorted chunks processed /
3550	#endif
3551
3552	/*
3553	Convert request size to internal form by adding SIZE_SZ bytes
3554	overhead plus possibly more to obtain necessary alignment and/or
3555	to obtain a size of at least MINSIZE, the smallest allocatable
3556	size. Also, checked_request2size traps (returning 0) request sizes
3557	that are so large that they wrap around zero when padded and
3558	aligned.
3559	*/
3560
3561	checked_request2size (bytes, nb);
3562
3563	/ There are no usable arenas. Fall back to sysmalloc to get a chunk from*
3564	mmap. /*
3565	if (__glibc_unlikely (av == NULL))
3566	{
3567	void *p = sysmalloc (nb, av);
3568	if (p != NULL)
3569	alloc_perturb (p, bytes);
3570	return p;
3571	}
3572
3573	/*
3574	If the size qualifies as a fastbin, first check corresponding bin.
3575	This code is safe to execute even if av is not yet initialized, so we
3576	can try it without checking, which saves some time on this fast path.
3577	*/
3578
3579	#define REMOVE_FB(fb, victim, pp) \
3580	do \
3581	{ \
3582	victim = pp; \
3583	if (victim == NULL) \
3584	break; \
3585	} \
3586	while ((pp = catomic_compare_and_exchange_val_acq (fb, victim->fd, victim)) \
3587	!= victim); \
3588
3589	if ((unsigned long) (nb) <= (unsigned long) (get_max_fast ()))
3590	{
3591	idx = fastbin_index (nb);
3592	mfastbinptr *fb = &fastbin (av, idx);
3593	mchunkptr pp;
3594	victim = *fb;
3595
3596	if (victim != NULL)
3597	{
3598	if (SINGLE_THREAD_P)
3599	*fb = victim->fd;
3600	else
3601	REMOVE_FB (fb, pp, victim);
3602	if (__glibc_likely (victim != NULL))
3603	{
3604	size_t victim_idx = fastbin_index (chunksize (victim));
3605	if (__builtin_expect (victim_idx != idx, `0`))
3606	malloc_printerr ("malloc(): memory corruption (fast)");
3607	check_remalloced_chunk (av, victim, nb);
3608	#if USE_TCACHE
3609	/ While we're here, if we see other chunks of the same size,*
3610	stash them in the tcache. /*
3611	size_t tc_idx = csize2tidx (nb);
3612	if (tcache && tc_idx < mp_.tcache_bins)
3613	{
3614	mchunkptr tc_victim;
3615
3616	/ While bin not empty and tcache not full, copy chunks. /
3617	while (tcache->counts[tc_idx] < mp_.tcache_count
3618	&& (tc_victim = *fb) != NULL)
3619	{
3620	if (SINGLE_THREAD_P)
3621	*fb = tc_victim->fd;
3622	else
3623	{
3624	REMOVE_FB (fb, pp, tc_victim);
3625	if (__glibc_unlikely (tc_victim == NULL))
3626	break;
3627	}
3628	tcache_put (tc_victim, tc_idx);
3629	}
3630	}
3631	#endif
3632	void *p = chunk2mem (victim);
3633	alloc_perturb (p, bytes);
3634	return p;
3635	}
3636	}
3637	}
3638
3639	/*
3640	If a small request, check regular bin. Since these "smallbins"
3641	hold one size each, no searching within bins is necessary.
3642	(For a large request, we need to wait until unsorted chunks are
3643	processed to find best fit. But for small ones, fits are exact
3644	anyway, so we can check now, which is faster.)
3645	*/
3646
3647	if (in_smallbin_range (nb))
3648	{
3649	idx = smallbin_index (nb);
3650	bin = bin_at (av, idx);
3651
3652	if ((victim = last (bin)) != bin)
3653	{
3654	bck = victim->bk;
3655	if (__glibc_unlikely (bck->fd != victim))
3656	malloc_printerr ("malloc(): smallbin double linked list corrupted");
3657	set_inuse_bit_at_offset (victim, nb);
3658	bin->bk = bck;
3659	bck->fd = bin;
3660
3661	if (av != &main_arena)
3662	set_non_main_arena (victim);
3663	check_malloced_chunk (av, victim, nb);
3664	#if USE_TCACHE
3665	/ While we're here, if we see other chunks of the same size,*
3666	stash them in the tcache. /*
3667	size_t tc_idx = csize2tidx (nb);
3668	if (tcache && tc_idx < mp_.tcache_bins)
3669	{
3670	mchunkptr tc_victim;
3671
3672	/ While bin not empty and tcache not full, copy chunks over. /
3673	while (tcache->counts[tc_idx] < mp_.tcache_count
3674	&& (tc_victim = last (bin)) != bin)
3675	{
3676	if (tc_victim != `0`)
3677	{
3678	bck = tc_victim->bk;
3679	set_inuse_bit_at_offset (tc_victim, nb);
3680	if (av != &main_arena)
3681	set_non_main_arena (tc_victim);
3682	bin->bk = bck;
3683	bck->fd = bin;
3684
3685	tcache_put (tc_victim, tc_idx);
3686	}
3687	}
3688	}
3689	#endif
3690	void *p = chunk2mem (victim);
3691	alloc_perturb (p, bytes);
3692	return p;
3693	}
3694	}
3695
3696	/*
3697	If this is a large request, consolidate fastbins before continuing.
3698	While it might look excessive to kill all fastbins before
3699	even seeing if there is space available, this avoids
3700	fragmentation problems normally associated with fastbins.
3701	Also, in practice, programs tend to have runs of either small or
3702	large requests, but less often mixtures, so consolidation is not
3703	invoked all that often in most programs. And the programs that
3704	it is called frequently in otherwise tend to fragment.
3705	*/
3706
3707	else
3708	{
3709	idx = largebin_index (nb);
3710	if (atomic_load_relaxed (&av->have_fastchunks))
3711	malloc_consolidate (av);
3712	}
3713
3714	/*
3715	Process recently freed or remaindered chunks, taking one only if
3716	it is exact fit, or, if this a small request, the chunk is remainder from
3717	the most recent non-exact fit. Place other traversed chunks in
3718	bins. Note that this step is the only place in any routine where
3719	chunks are placed in bins.
3720
3721	The outer loop here is needed because we might not realize until
3722	near the end of malloc that we should have consolidated, so must
3723	do so and retry. This happens at most once, and only when we would
3724	otherwise need to expand memory to service a "small" request.
3725	*/
3726
3727	#if USE_TCACHE
3728	INTERNAL_SIZE_T tcache_nb = `0`;
3729	size_t tc_idx = csize2tidx (nb);
3730	if (tcache && tc_idx < mp_.tcache_bins)
3731	tcache_nb = nb;
3732	int return_cached = `0`;
3733
3734	tcache_unsorted_count = `0`;
3735	#endif
3736
3737	for (;; )
3738	{
3739	int iters = `0`;
3740	while ((victim = unsorted_chunks (av)->bk) != unsorted_chunks (av))
3741	{
3742	bck = victim->bk;
3743	size = chunksize (victim);
3744	mchunkptr next = chunk_at_offset (victim, size);
3745
3746	if (__glibc_unlikely (size <= `2` * SIZE_SZ)
3747	\|\| __glibc_unlikely (size > av->system_mem))
3748	malloc_printerr ("malloc(): invalid size (unsorted)");
3749	if (__glibc_unlikely (chunksize_nomask (next) < `2` * SIZE_SZ)
3750	\|\| __glibc_unlikely (chunksize_nomask (next) > av->system_mem))
3751	malloc_printerr ("malloc(): invalid next size (unsorted)");
3752	if (__glibc_unlikely ((prev_size (next) & ~(SIZE_BITS)) != size))
3753	malloc_printerr ("malloc(): mismatching next->prev_size (unsorted)");
3754	if (__glibc_unlikely (bck->fd != victim)
3755	\|\| __glibc_unlikely (victim->fd != unsorted_chunks (av)))
3756	malloc_printerr ("malloc(): unsorted double linked list corrupted");
3757	if (__glibc_unlikely (prev_inuse (next)))
3758	malloc_printerr ("malloc(): invalid next->prev_inuse (unsorted)");
3759
3760	/*
3761	If a small request, try to use last remainder if it is the
3762	only chunk in unsorted bin. This helps promote locality for
3763	runs of consecutive small requests. This is the only
3764	exception to best-fit, and applies only when there is
3765	no exact fit for a small chunk.
3766	*/
3767
3768	if (in_smallbin_range (nb) &&
3769	bck == unsorted_chunks (av) &&
3770	victim == av->last_remainder &&
3771	(unsigned long) (size) > (unsigned long) (nb + MINSIZE))
3772	{
3773	/ split and reattach remainder /
3774	remainder_size = size - nb;
3775	remainder = chunk_at_offset (victim, nb);
3776	unsorted_chunks (av)->bk = unsorted_chunks (av)->fd = remainder;
3777	av->last_remainder = remainder;
3778	remainder->bk = remainder->fd = unsorted_chunks (av);
3779	if (!in_smallbin_range (remainder_size))
3780	{
3781	remainder->fd_nextsize = NULL;
3782	remainder->bk_nextsize = NULL;
3783	}
3784
3785	set_head (victim, nb \| PREV_INUSE \|
3786	(av != &main_arena ? NON_MAIN_ARENA : `0`));
3787	set_head (remainder, remainder_size \| PREV_INUSE);
3788	set_foot (remainder, remainder_size);
3789
3790	check_malloced_chunk (av, victim, nb);
3791	void *p = chunk2mem (victim);
3792	alloc_perturb (p, bytes);
3793	return p;
3794	}
3795
3796	/ remove from unsorted list /
3797	if (__glibc_unlikely (bck->fd != victim))
3798	malloc_printerr ("malloc(): corrupted unsorted chunks 3");
3799	unsorted_chunks (av)->bk = bck;
3800	bck->fd = unsorted_chunks (av);
3801
3802	/ Take now instead of binning if exact fit /
3803
3804	if (size == nb)
3805	{
3806	set_inuse_bit_at_offset (victim, size);
3807	if (av != &main_arena)
3808	set_non_main_arena (victim);
3809	#if USE_TCACHE
3810	/ Fill cache first, return to user only if cache fills.*
3811	We may return one of these chunks later. /*
3812	if (tcache_nb
3813	&& tcache->counts[tc_idx] < mp_.tcache_count)
3814	{
3815	tcache_put (victim, tc_idx);
3816	return_cached = `1`;
3817	continue;
3818	}
3819	else
3820	{
3821	#endif
3822	check_malloced_chunk (av, victim, nb);
3823	void *p = chunk2mem (victim);
3824	alloc_perturb (p, bytes);
3825	return p;
3826	#if USE_TCACHE
3827	}
3828	#endif
3829	}
3830
3831	/ place chunk in bin /
3832
3833	if (in_smallbin_range (size))
3834	{
3835	victim_index = smallbin_index (size);
3836	bck = bin_at (av, victim_index);
3837	fwd = bck->fd;
3838	}
3839	else
3840	{
3841	victim_index = largebin_index (size);
3842	bck = bin_at (av, victim_index);
3843	fwd = bck->fd;
3844
3845	/ maintain large bins in sorted order /
3846	if (fwd != bck)
3847	{
3848	/ Or with inuse bit to speed comparisons /
3849	size \|= PREV_INUSE;
3850	/ if smaller than smallest, bypass loop below /
3851	assert (chunk_main_arena (bck->bk));
3852	if ((unsigned long) (size)
3853	< (unsigned long) chunksize_nomask (bck->bk))
3854	{
3855	fwd = bck;
3856	bck = bck->bk;
3857
3858	victim->fd_nextsize = fwd->fd;
3859	victim->bk_nextsize = fwd->fd->bk_nextsize;
3860	fwd->fd->bk_nextsize = victim->bk_nextsize->fd_nextsize = victim;
3861	}
3862	else
3863	{
3864	assert (chunk_main_arena (fwd));
3865	while ((unsigned long) size < chunksize_nomask (fwd))
3866	{
3867	fwd = fwd->fd_nextsize;
3868	assert (chunk_main_arena (fwd));
3869	}
3870
3871	if ((unsigned long) size
3872	== (unsigned long) chunksize_nomask (fwd))
3873	/ Always insert in the second position. /
3874	fwd = fwd->fd;
3875	else
3876	{
3877	victim->fd_nextsize = fwd;
3878	victim->bk_nextsize = fwd->bk_nextsize;
3879	fwd->bk_nextsize = victim;
3880	victim->bk_nextsize->fd_nextsize = victim;
3881	}
3882	bck = fwd->bk;
3883	}
3884	}
3885	else
3886	victim->fd_nextsize = victim->bk_nextsize = victim;
3887	}
3888
3889	mark_bin (av, victim_index);
3890	victim->bk = bck;
3891	victim->fd = fwd;
3892	fwd->bk = victim;
3893	bck->fd = victim;
3894
3895	#if USE_TCACHE
3896	/ If we've processed as many chunks as we're allowed while*
3897	filling the cache, return one of the cached ones. /*
3898	++tcache_unsorted_count;
3899	if (return_cached
3900	&& mp_.tcache_unsorted_limit > `0`
3901	&& tcache_unsorted_count > mp_.tcache_unsorted_limit)
3902	{
3903	return tcache_get (tc_idx);
3904	}
3905	#endif
3906
3907	#define MAX_ITERS 10000
3908	if (++iters >= MAX_ITERS)
3909	break;
3910	}
3911
3912	#if USE_TCACHE
3913	/ If all the small chunks we found ended up cached, return one now. /
3914	if (return_cached)
3915	{
3916	return tcache_get (tc_idx);
3917	}
3918	#endif
3919
3920	/*
3921	If a large request, scan through the chunks of current bin in
3922	sorted order to find smallest that fits. Use the skip list for this.
3923	*/
3924
3925	if (!in_smallbin_range (nb))
3926	{
3927	bin = bin_at (av, idx);
3928
3929	/ skip scan if empty or largest chunk is too small /
3930	if ((victim = first (bin)) != bin
3931	&& (unsigned long) chunksize_nomask (victim)
3932	>= (unsigned long) (nb))
3933	{
3934	victim = victim->bk_nextsize;
3935	while (((unsigned long) (size = chunksize (victim)) <
3936	(unsigned long) (nb)))
3937	victim = victim->bk_nextsize;
3938
3939	/ Avoid removing the first entry for a size so that the skip*
3940	list does not have to be rerouted. /*
3941	if (victim != last (bin)
3942	&& chunksize_nomask (victim)
3943	== chunksize_nomask (victim->fd))
3944	victim = victim->fd;
3945
3946	remainder_size = size - nb;
3947	unlink_chunk (av, victim);
3948
3949	/ Exhaust /
3950	if (remainder_size < MINSIZE)
3951	{
3952	set_inuse_bit_at_offset (victim, size);
3953	if (av != &main_arena)
3954	set_non_main_arena (victim);
3955	}
3956	/ Split /
3957	else
3958	{
3959	remainder = chunk_at_offset (victim, nb);
3960	/ We cannot assume the unsorted list is empty and therefore*
3961	have to perform a complete insert here. /*
3962	bck = unsorted_chunks (av);
3963	fwd = bck->fd;
3964	if (__glibc_unlikely (fwd->bk != bck))
3965	malloc_printerr ("malloc(): corrupted unsorted chunks");
3966	remainder->bk = bck;
3967	remainder->fd = fwd;
3968	bck->fd = remainder;
3969	fwd->bk = remainder;
3970	if (!in_smallbin_range (remainder_size))
3971	{
3972	remainder->fd_nextsize = NULL;
3973	remainder->bk_nextsize = NULL;
3974	}
3975	set_head (victim, nb \| PREV_INUSE \|
3976	(av != &main_arena ? NON_MAIN_ARENA : `0`));
3977	set_head (remainder, remainder_size \| PREV_INUSE);
3978	set_foot (remainder, remainder_size);
3979	}
3980	check_malloced_chunk (av, victim, nb);
3981	void *p = chunk2mem (victim);
3982	alloc_perturb (p, bytes);
3983	return p;
3984	}
3985	}
3986
3987	/*
3988	Search for a chunk by scanning bins, starting with next largest
3989	bin. This search is strictly by best-fit; i.e., the smallest
3990	(with ties going to approximately the least recently used) chunk
3991	that fits is selected.
3992
3993	The bitmap avoids needing to check that most blocks are nonempty.
3994	The particular case of skipping all bins during warm-up phases
3995	when no chunks have been returned yet is faster than it might look.
3996	*/
3997
3998	++idx;
3999	bin = bin_at (av, idx);
4000	block = idx2block (idx);
4001	map = av->binmap[block];
4002	bit = idx2bit (idx);
4003
4004	for (;; )
4005	{
4006	/ Skip rest of block if there are no more set bits in this block. /
4007	if (bit > map \|\| bit == `0`)
4008	{
4009	do
4010	{
4011	if (++block >= BINMAPSIZE) / out of bins /
4012	goto use_top;
4013	}
4014	while ((map = av->binmap[block]) == `0`);
4015
4016	bin = bin_at (av, (block << BINMAPSHIFT));
4017	bit = `1`;
4018	}
4019
4020	/ Advance to bin with set bit. There must be one. /
4021	while ((bit & map) == `0`)
4022	{
4023	bin = next_bin (bin);
4024	bit <<= `1`;
4025	assert (bit != `0`);
4026	}
4027
4028	/ Inspect the bin. It is likely to be non-empty /
4029	victim = last (bin);
4030
4031	/ If a false alarm (empty bin), clear the bit. /
4032	if (victim == bin)
4033	{
4034	av->binmap[block] = map &= ~bit; / Write through /
4035	bin = next_bin (bin);
4036	bit <<= `1`;
4037	}
4038
4039	else
4040	{
4041	size = chunksize (victim);
4042
4043	/ We know the first chunk in this bin is big enough to use. /
4044	assert ((unsigned long) (size) >= (unsigned long) (nb));
4045
4046	remainder_size = size - nb;
4047
4048	/ unlink /
4049	unlink_chunk (av, victim);
4050
4051	/ Exhaust /
4052	if (remainder_size < MINSIZE)
4053	{
4054	set_inuse_bit_at_offset (victim, size);
4055	if (av != &main_arena)
4056	set_non_main_arena (victim);
4057	}
4058
4059	/ Split /
4060	else
4061	{
4062	remainder = chunk_at_offset (victim, nb);
4063
4064	/ We cannot assume the unsorted list is empty and therefore*
4065	have to perform a complete insert here. /*
4066	bck = unsorted_chunks (av);
4067	fwd = bck->fd;
4068	if (__glibc_unlikely (fwd->bk != bck))
4069	malloc_printerr ("malloc(): corrupted unsorted chunks 2");
4070	remainder->bk = bck;
4071	remainder->fd = fwd;
4072	bck->fd = remainder;
4073	fwd->bk = remainder;
4074
4075	/ advertise as last remainder /
4076	if (in_smallbin_range (nb))
4077	av->last_remainder = remainder;
4078	if (!in_smallbin_range (remainder_size))
4079	{
4080	remainder->fd_nextsize = NULL;
4081	remainder->bk_nextsize = NULL;
4082	}
4083	set_head (victim, nb \| PREV_INUSE \|
4084	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4085	set_head (remainder, remainder_size \| PREV_INUSE);
4086	set_foot (remainder, remainder_size);
4087	}
4088	check_malloced_chunk (av, victim, nb);
4089	void *p = chunk2mem (victim);
4090	alloc_perturb (p, bytes);
4091	return p;
4092	}
4093	}
4094
4095	use_top:
4096	/*
4097	If large enough, split off the chunk bordering the end of memory
4098	(held in av->top). Note that this is in accord with the best-fit
4099	search rule. In effect, av->top is treated as larger (and thus
4100	less well fitting) than any other available chunk since it can
4101	be extended to be as large as necessary (up to system
4102	limitations).
4103
4104	We require that av->top always exists (i.e., has size >=
4105	MINSIZE) after initialization, so if it would otherwise be
4106	exhausted by current request, it is replenished. (The main
4107	reason for ensuring it exists is that we may need MINSIZE space
4108	to put in fenceposts in sysmalloc.)
4109	*/
4110
4111	victim = av->top;
4112	size = chunksize (victim);
4113
4114	if (__glibc_unlikely (size > av->system_mem))
4115	malloc_printerr ("malloc(): corrupted top size");
4116
4117	if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
4118	{
4119	remainder_size = size - nb;
4120	remainder = chunk_at_offset (victim, nb);
4121	av->top = remainder;
4122	set_head (victim, nb \| PREV_INUSE \|
4123	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4124	set_head (remainder, remainder_size \| PREV_INUSE);
4125
4126	check_malloced_chunk (av, victim, nb);
4127	void *p = chunk2mem (victim);
4128	alloc_perturb (p, bytes);
4129	return p;
4130	}
4131
4132	/ When we are using atomic ops to free fast chunks we can get*
4133	here for all block sizes. /*
4134	else if (atomic_load_relaxed (&av->have_fastchunks))
4135	{
4136	malloc_consolidate (av);
4137	/ restore original bin index /
4138	if (in_smallbin_range (nb))
4139	idx = smallbin_index (nb);
4140	else
4141	idx = largebin_index (nb);
4142	}
4143
4144	/*
4145	Otherwise, relay to handle system-dependent cases
4146	*/
4147	else
4148	{
4149	void *p = sysmalloc (nb, av);
4150	if (p != NULL)
4151	alloc_perturb (p, bytes);
4152	return p;
4153	}
4154	}
4155	}
4156
4157	/*
4158	------------------------------ free ------------------------------
4159	*/
4160
4161	static void
4162	_int_free (mstate av, mchunkptr p, int have_lock)
4163	{
4164	INTERNAL_SIZE_T size; / its size /
4165	mfastbinptr fb; /* associated fastbin /
4166	mchunkptr nextchunk; / next contiguous chunk /
4167	INTERNAL_SIZE_T nextsize; / its size /
4168	int nextinuse; / true if nextchunk is used /
4169	INTERNAL_SIZE_T prevsize; / size of previous contiguous chunk /
4170	mchunkptr bck; / misc temp for linking /
4171	mchunkptr fwd; / misc temp for linking /
4172
4173	size = chunksize (p);
4174
4175	/ Little security check which won't hurt performance: the*
4176	allocator never wrapps around at the end of the address space.
4177	Therefore we can exclude some size values which might appear
4178	here by accident or by "design" from some intruder. /*
4179	if (__builtin_expect ((uintptr_t) p > (uintptr_t) -size, `0`)
4180	\|\| __builtin_expect (misaligned_chunk (p), `0`))
4181	malloc_printerr ("free(): invalid pointer");
4182	/ We know that each chunk is at least MINSIZE bytes in size or a*
4183	multiple of MALLOC_ALIGNMENT. /*
4184	if (__glibc_unlikely (size < MINSIZE \|\| !aligned_OK (size)))
4185	malloc_printerr ("free(): invalid size");
4186
4187	check_inuse_chunk(av, p);
4188
4189	#if USE_TCACHE
4190	{
4191	size_t tc_idx = csize2tidx (size);
4192	if (tcache != NULL && tc_idx < mp_.tcache_bins)
4193	{
4194	/ Check to see if it's already in the tcache. /
4195	tcache_entry e = (tcache_entry ) chunk2mem (p);
4196
4197	/ This test succeeds on double free. However, we don't 100%*
4198	trust it (it also matches random payload data at a 1 in
4199	2^<size_t> chance), so verify it's not an unlikely
4200	coincidence before aborting. /*
4201	if (__glibc_unlikely (e->key == tcache))
4202	{
4203	tcache_entry *tmp;
4204	LIBC_PROBE (memory_tcache_double_free, `2`, e, tc_idx);
4205	for (tmp = tcache->entries[tc_idx];
4206	tmp;
4207	tmp = tmp->next)
4208	if (tmp == e)
4209	malloc_printerr ("free(): double free detected in tcache 2");
4210	/ If we get here, it was a coincidence. We've wasted a*
4211	few cycles, but don't abort. /*
4212	}
4213
4214	if (tcache->counts[tc_idx] < mp_.tcache_count)
4215	{
4216	tcache_put (p, tc_idx);
4217	return;
4218	}
4219	}
4220	}
4221	#endif
4222
4223	/*
4224	If eligible, place chunk on a fastbin so it can be found
4225	and used quickly in malloc.
4226	*/
4227
4228	if ((unsigned long)(size) <= (unsigned long)(get_max_fast ())
4229
4230	#if TRIM_FASTBINS
4231	/*
4232	If TRIM_FASTBINS set, don't place chunks
4233	bordering top into fastbins
4234	*/
4235	&& (chunk_at_offset(p, size) != av->top)
4236	#endif
4237	) {
4238
4239	if (__builtin_expect (chunksize_nomask (chunk_at_offset (p, size))
4240	<= `2` * SIZE_SZ, `0`)
4241	\|\| __builtin_expect (chunksize (chunk_at_offset (p, size))
4242	>= av->system_mem, `0`))
4243	{
4244	bool fail = true;
4245	/ We might not have a lock at this point and concurrent modifications*
4246	of system_mem might result in a false positive. Redo the test after
4247	getting the lock. /*
4248	if (!have_lock)
4249	{
4250	__libc_lock_lock (av->mutex);
4251	fail = (chunksize_nomask (chunk_at_offset (p, size)) <= `2` * SIZE_SZ
4252	\|\| chunksize (chunk_at_offset (p, size)) >= av->system_mem);
4253	__libc_lock_unlock (av->mutex);
4254	}
4255
4256	if (fail)
4257	malloc_printerr ("free(): invalid next size (fast)");
4258	}
4259
4260	free_perturb (chunk2mem(p), size - `2` * SIZE_SZ);
4261
4262	atomic_store_relaxed (&av->have_fastchunks, true);
4263	unsigned int idx = fastbin_index(size);
4264	fb = &fastbin (av, idx);
4265
4266	/ Atomically link P to its fastbin: P->FD = FB; FB = P; /
4267	mchunkptr old = *fb, old2;
4268
4269	if (SINGLE_THREAD_P)
4270	{
4271	/ Check that the top of the bin is not the record we are going to*
4272	add (i.e., double free). /*
4273	if (__builtin_expect (old == p, `0`))
4274	malloc_printerr ("double free or corruption (fasttop)");
4275	p->fd = old;
4276	*fb = p;
4277	}
4278	else
4279	do
4280	{
4281	/ Check that the top of the bin is not the record we are going to*
4282	add (i.e., double free). /*
4283	if (__builtin_expect (old == p, `0`))
4284	malloc_printerr ("double free or corruption (fasttop)");
4285	p->fd = old2 = old;
4286	}
4287	while ((old = catomic_compare_and_exchange_val_rel (fb, p, old2))
4288	!= old2);
4289
4290	/ Check that size of fastbin chunk at the top is the same as*
4291	size of the chunk that we are adding. We can dereference OLD
4292	only if we have the lock, otherwise it might have already been
4293	allocated again. /*
4294	if (have_lock && old != NULL
4295	&& __builtin_expect (fastbin_index (chunksize (old)) != idx, `0`))
4296	malloc_printerr ("invalid fastbin entry (free)");
4297	}
4298
4299	/*
4300	Consolidate other non-mmapped chunks as they arrive.
4301	*/
4302
4303	else if (!chunk_is_mmapped(p)) {
4304
4305	/ If we're single-threaded, don't lock the arena. /
4306	if (SINGLE_THREAD_P)
4307	have_lock = true;
4308
4309	if (!have_lock)
4310	__libc_lock_lock (av->mutex);
4311
4312	nextchunk = chunk_at_offset(p, size);
4313
4314	/ Lightweight tests: check whether the block is already the*
4315	top block. /*
4316	if (__glibc_unlikely (p == av->top))
4317	malloc_printerr ("double free or corruption (top)");
4318	/ Or whether the next chunk is beyond the boundaries of the arena. /
4319	if (__builtin_expect (contiguous (av)
4320	&& (char *) nextchunk
4321	>= ((char *) av->top + chunksize(av->top)), `0`))
4322	malloc_printerr ("double free or corruption (out)");
4323	/ Or whether the block is actually not marked used. /
4324	if (__glibc_unlikely (!prev_inuse(nextchunk)))
4325	malloc_printerr ("double free or corruption (!prev)");
4326
4327	nextsize = chunksize(nextchunk);
4328	if (__builtin_expect (chunksize_nomask (nextchunk) <= `2` * SIZE_SZ, `0`)
4329	\|\| __builtin_expect (nextsize >= av->system_mem, `0`))
4330	malloc_printerr ("free(): invalid next size (normal)");
4331
4332	free_perturb (chunk2mem(p), size - `2` * SIZE_SZ);
4333
4334	/ consolidate backward /
4335	if (!prev_inuse(p)) {
4336	prevsize = prev_size (p);
4337	size += prevsize;
4338	p = chunk_at_offset(p, -((long) prevsize));
4339	if (__glibc_unlikely (chunksize(p) != prevsize))
4340	malloc_printerr ("corrupted size vs. prev_size while consolidating");
4341	unlink_chunk (av, p);
4342	}
4343
4344	if (nextchunk != av->top) {
4345	/ get and clear inuse bit /
4346	nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
4347
4348	/ consolidate forward /
4349	if (!nextinuse) {
4350	unlink_chunk (av, nextchunk);
4351	size += nextsize;
4352	} else
4353	clear_inuse_bit_at_offset(nextchunk, `0`);
4354
4355	/*
4356	Place the chunk in unsorted chunk list. Chunks are
4357	not placed into regular bins until after they have
4358	been given one chance to be used in malloc.
4359	*/
4360
4361	bck = unsorted_chunks(av);
4362	fwd = bck->fd;
4363	if (__glibc_unlikely (fwd->bk != bck))
4364	malloc_printerr ("free(): corrupted unsorted chunks");
4365	p->fd = fwd;
4366	p->bk = bck;
4367	if (!in_smallbin_range(size))
4368	{
4369	p->fd_nextsize = NULL;
4370	p->bk_nextsize = NULL;
4371	}
4372	bck->fd = p;
4373	fwd->bk = p;
4374
4375	set_head(p, size \| PREV_INUSE);
4376	set_foot(p, size);
4377
4378	check_free_chunk(av, p);
4379	}
4380
4381	/*
4382	If the chunk borders the current high end of memory,
4383	consolidate into top
4384	*/
4385
4386	else {
4387	size += nextsize;
4388	set_head(p, size \| PREV_INUSE);
4389	av->top = p;
4390	check_chunk(av, p);
4391	}
4392
4393	/*
4394	If freeing a large space, consolidate possibly-surrounding
4395	chunks. Then, if the total unused topmost memory exceeds trim
4396	threshold, ask malloc_trim to reduce top.
4397
4398	Unless max_fast is 0, we don't know if there are fastbins
4399	bordering top, so we cannot tell for sure whether threshold
4400	has been reached unless fastbins are consolidated. But we
4401	don't want to consolidate on each free. As a compromise,
4402	consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD
4403	is reached.
4404	*/
4405
4406	if ((unsigned long)(size) >= FASTBIN_CONSOLIDATION_THRESHOLD) {
4407	if (atomic_load_relaxed (&av->have_fastchunks))
4408	malloc_consolidate(av);
4409
4410	if (av == &main_arena) {
4411	#ifndef MORECORE_CANNOT_TRIM
4412	if ((unsigned long)(chunksize(av->top)) >=
4413	(unsigned long)(mp_.trim_threshold))
4414	systrim(mp_.top_pad, av);
4415	#endif
4416	} else {
4417	/ Always try heap_trim(), even if the top chunk is not*
4418	large, because the corresponding heap might go away. /*
4419	heap_info *heap = heap_for_ptr(top(av));
4420
4421	assert(heap->ar_ptr == av);
4422	heap_trim(heap, mp_.top_pad);
4423	}
4424	}
4425
4426	if (!have_lock)
4427	__libc_lock_unlock (av->mutex);
4428	}
4429	/*
4430	If the chunk was allocated via mmap, release via munmap().
4431	*/
4432
4433	else {
4434	munmap_chunk (p);
4435	}
4436	}
4437
4438	/*
4439	------------------------- malloc_consolidate -------------------------
4440
4441	malloc_consolidate is a specialized version of free() that tears
4442	down chunks held in fastbins. Free itself cannot be used for this
4443	purpose since, among other things, it might place chunks back onto
4444	fastbins. So, instead, we need to use a minor variant of the same
4445	code.
4446	*/
4447
4448	static void malloc_consolidate(mstate av)
4449	{
4450	mfastbinptr* fb; / current fastbin being consolidated /
4451	mfastbinptr* maxfb; / last fastbin (for loop control) /
4452	mchunkptr p; / current chunk being consolidated /
4453	mchunkptr nextp; / next chunk to consolidate /
4454	mchunkptr unsorted_bin; / bin header /
4455	mchunkptr first_unsorted; / chunk to link to /
4456
4457	/ These have same use as in free() /
4458	mchunkptr nextchunk;
4459	INTERNAL_SIZE_T size;
4460	INTERNAL_SIZE_T nextsize;
4461	INTERNAL_SIZE_T prevsize;
4462	int nextinuse;
4463
4464	atomic_store_relaxed (&av->have_fastchunks, false);
4465
4466	unsorted_bin = unsorted_chunks(av);
4467
4468	/*
4469	Remove each chunk from fast bin and consolidate it, placing it
4470	then in unsorted bin. Among other reasons for doing this,
4471	placing in unsorted bin avoids needing to calculate actual bins
4472	until malloc is sure that chunks aren't immediately going to be
4473	reused anyway.
4474	*/
4475
4476	maxfb = &fastbin (av, NFASTBINS - `1`);
4477	fb = &fastbin (av, `0`);
4478	do {
4479	p = atomic_exchange_acq (fb, NULL);
4480	if (p != `0`) {
4481	do {
4482	{
4483	unsigned int idx = fastbin_index (chunksize (p));
4484	if ((&fastbin (av, idx)) != fb)
4485	malloc_printerr ("malloc_consolidate(): invalid chunk size");
4486	}
4487
4488	check_inuse_chunk(av, p);
4489	nextp = p->fd;
4490
4491	/ Slightly streamlined version of consolidation code in free() /
4492	size = chunksize (p);
4493	nextchunk = chunk_at_offset(p, size);
4494	nextsize = chunksize(nextchunk);
4495
4496	if (!prev_inuse(p)) {
4497	prevsize = prev_size (p);
4498	size += prevsize;
4499	p = chunk_at_offset(p, -((long) prevsize));
4500	if (__glibc_unlikely (chunksize(p) != prevsize))
4501	malloc_printerr ("corrupted size vs. prev_size in fastbins");
4502	unlink_chunk (av, p);
4503	}
4504
4505	if (nextchunk != av->top) {
4506	nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
4507
4508	if (!nextinuse) {
4509	size += nextsize;
4510	unlink_chunk (av, nextchunk);
4511	} else
4512	clear_inuse_bit_at_offset(nextchunk, `0`);
4513
4514	first_unsorted = unsorted_bin->fd;
4515	unsorted_bin->fd = p;
4516	first_unsorted->bk = p;
4517
4518	if (!in_smallbin_range (size)) {
4519	p->fd_nextsize = NULL;
4520	p->bk_nextsize = NULL;
4521	}
4522
4523	set_head(p, size \| PREV_INUSE);
4524	p->bk = unsorted_bin;
4525	p->fd = first_unsorted;
4526	set_foot(p, size);
4527	}
4528
4529	else {
4530	size += nextsize;
4531	set_head(p, size \| PREV_INUSE);
4532	av->top = p;
4533	}
4534
4535	} while ( (p = nextp) != `0`);
4536
4537	}
4538	} while (fb++ != maxfb);
4539	}
4540
4541	/*
4542	------------------------------ realloc ------------------------------
4543	*/
4544
4545	void*
4546	_int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize,
4547	INTERNAL_SIZE_T nb)
4548	{
4549	mchunkptr newp; / chunk to return /
4550	INTERNAL_SIZE_T newsize; / its size /
4551	void* newmem; / corresponding user mem /
4552
4553	mchunkptr next; / next contiguous chunk after oldp /
4554
4555	mchunkptr remainder; / extra space at end of newp /
4556	unsigned long remainder_size; / its size /
4557
4558	/ oldmem size /
4559	if (__builtin_expect (chunksize_nomask (oldp) <= `2` * SIZE_SZ, `0`)
4560	\|\| __builtin_expect (oldsize >= av->system_mem, `0`))
4561	malloc_printerr ("realloc(): invalid old size");
4562
4563	check_inuse_chunk (av, oldp);
4564
4565	/ All callers already filter out mmap'ed chunks. /
4566	assert (!chunk_is_mmapped (oldp));
4567
4568	next = chunk_at_offset (oldp, oldsize);
4569	INTERNAL_SIZE_T nextsize = chunksize (next);
4570	if (__builtin_expect (chunksize_nomask (next) <= `2` * SIZE_SZ, `0`)
4571	\|\| __builtin_expect (nextsize >= av->system_mem, `0`))
4572	malloc_printerr ("realloc(): invalid next size");
4573
4574	if ((unsigned long) (oldsize) >= (unsigned long) (nb))
4575	{
4576	/ already big enough; split below /
4577	newp = oldp;
4578	newsize = oldsize;
4579	}
4580
4581	else
4582	{
4583	/ Try to expand forward into top /
4584	if (next == av->top &&
4585	(unsigned long) (newsize = oldsize + nextsize) >=
4586	(unsigned long) (nb + MINSIZE))
4587	{
4588	set_head_size (oldp, nb \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4589	av->top = chunk_at_offset (oldp, nb);
4590	set_head (av->top, (newsize - nb) \| PREV_INUSE);
4591	check_inuse_chunk (av, oldp);
4592	return chunk2mem (oldp);
4593	}
4594
4595	/ Try to expand forward into next chunk; split off remainder below /
4596	else if (next != av->top &&
4597	!inuse (next) &&
4598	(unsigned long) (newsize = oldsize + nextsize) >=
4599	(unsigned long) (nb))
4600	{
4601	newp = oldp;
4602	unlink_chunk (av, next);
4603	}
4604
4605	/ allocate, copy, free /
4606	else
4607	{
4608	newmem = _int_malloc (av, nb - MALLOC_ALIGN_MASK);
4609	if (newmem == `0`)
4610	return `0`; / propagate failure /
4611
4612	newp = mem2chunk (newmem);
4613	newsize = chunksize (newp);
4614
4615	/*
4616	Avoid copy if newp is next chunk after oldp.
4617	*/
4618	if (newp == next)
4619	{
4620	newsize += oldsize;
4621	newp = oldp;
4622	}
4623	else
4624	{
4625	memcpy (newmem, chunk2mem (oldp), oldsize - SIZE_SZ);
4626	_int_free (av, oldp, `1`);
4627	check_inuse_chunk (av, newp);
4628	return chunk2mem (newp);
4629	}
4630	}
4631	}
4632
4633	/ If possible, free extra space in old or extended chunk /
4634
4635	assert ((unsigned long) (newsize) >= (unsigned long) (nb));
4636
4637	remainder_size = newsize - nb;
4638
4639	if (remainder_size < MINSIZE) / not enough extra to split off /
4640	{
4641	set_head_size (newp, newsize \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4642	set_inuse_bit_at_offset (newp, newsize);
4643	}
4644	else / split remainder /
4645	{
4646	remainder = chunk_at_offset (newp, nb);
4647	set_head_size (newp, nb \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4648	set_head (remainder, remainder_size \| PREV_INUSE \|
4649	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4650	/ Mark remainder as inuse so free() won't complain /
4651	set_inuse_bit_at_offset (remainder, remainder_size);
4652	_int_free (av, remainder, `1`);
4653	}
4654
4655	check_inuse_chunk (av, newp);
4656	return chunk2mem (newp);
4657	}
4658
4659	/*
4660	------------------------------ memalign ------------------------------
4661	*/
4662
4663	static void *
4664	_int_memalign (mstate av, size_t alignment, size_t bytes)
4665	{
4666	INTERNAL_SIZE_T nb; / padded request size /
4667	char m; /* memory returned by malloc call /
4668	mchunkptr p; / corresponding chunk /
4669	char brk; /* alignment point within p /
4670	mchunkptr newp; / chunk to return /
4671	INTERNAL_SIZE_T newsize; / its size /
4672	INTERNAL_SIZE_T leadsize; / leading space before alignment point /
4673	mchunkptr remainder; / spare room at end to split off /
4674	unsigned long remainder_size; / its size /
4675	INTERNAL_SIZE_T size;
4676
4677
4678
4679	checked_request2size (bytes, nb);
4680
4681	/*
4682	Strategy: find a spot within that chunk that meets the alignment
4683	request, and then possibly free the leading and trailing space.
4684	*/
4685
4686
4687	/ Check for overflow. /
4688	if (nb > SIZE_MAX - alignment - MINSIZE)
4689	{
4690	__set_errno (ENOMEM);
4691	return `0`;
4692	}
4693
4694	/ Call malloc with worst case padding to hit alignment. /
4695
4696	m = (char *) (_int_malloc (av, nb + alignment + MINSIZE));
4697
4698	if (m == `0`)
4699	return `0`; / propagate failure /
4700
4701	p = mem2chunk (m);
4702
4703	if ((((unsigned long) (m)) % alignment) != `0`) / misaligned /
4704
4705	{ /*
4706	Find an aligned spot inside chunk. Since we need to give back
4707	leading space in a chunk of at least MINSIZE, if the first
4708	calculation places us at a spot with less than MINSIZE leader,
4709	we can move to the next aligned spot -- we've allocated enough
4710	total room so that this is always possible.
4711	*/
4712	brk = (char ) mem2chunk (((unsigned* long) (m + alignment - `1`)) &
4713	- ((signed long) alignment));
4714	if ((unsigned long) (brk - (char *) (p)) < MINSIZE)
4715	brk += alignment;
4716
4717	newp = (mchunkptr) brk;
4718	leadsize = brk - (char *) (p);
4719	newsize = chunksize (p) - leadsize;
4720
4721	/ For mmapped chunks, just adjust offset /
4722	if (chunk_is_mmapped (p))
4723	{
4724	set_prev_size (newp, prev_size (p) + leadsize);
4725	set_head (newp, newsize \| IS_MMAPPED);
4726	return chunk2mem (newp);
4727	}
4728
4729	/ Otherwise, give back leader, use the rest /
4730	set_head (newp, newsize \| PREV_INUSE \|
4731	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4732	set_inuse_bit_at_offset (newp, newsize);
4733	set_head_size (p, leadsize \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4734	_int_free (av, p, `1`);
4735	p = newp;
4736
4737	assert (newsize >= nb &&
4738	(((unsigned long) (chunk2mem (p))) % alignment) == `0`);
4739	}
4740
4741	/ Also give back spare room at the end /
4742	if (!chunk_is_mmapped (p))
4743	{
4744	size = chunksize (p);
4745	if ((unsigned long) (size) > (unsigned long) (nb + MINSIZE))
4746	{
4747	remainder_size = size - nb;
4748	remainder = chunk_at_offset (p, nb);
4749	set_head (remainder, remainder_size \| PREV_INUSE \|
4750	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4751	set_head_size (p, nb);
4752	_int_free (av, remainder, `1`);
4753	}
4754	}
4755
4756	check_inuse_chunk (av, p);
4757	return chunk2mem (p);
4758	}
4759
4760
4761	/*
4762	------------------------------ malloc_trim ------------------------------
4763	*/
4764
4765	static int
4766	mtrim (mstate av, size_t pad)
4767	{
4768	/ Ensure all blocks are consolidated. /
4769	malloc_consolidate (av);
4770
4771	const size_t ps = GLRO (dl_pagesize);
4772	int psindex = bin_index (ps);
4773	const size_t psm1 = ps - `1`;
4774
4775	int result = `0`;
4776	for (int i = `1`; i < NBINS; ++i)
4777	if (i == `1` \|\| i >= psindex)
4778	{
4779	mbinptr bin = bin_at (av, i);
4780
4781	for (mchunkptr p = last (bin); p != bin; p = p->bk)
4782	{
4783	INTERNAL_SIZE_T size = chunksize (p);
4784
4785	if (size > psm1 + sizeof (struct malloc_chunk))
4786	{
4787	/ See whether the chunk contains at least one unused page. /
4788	char paligned_mem = (char* *) (((uintptr_t) p
4789	+ sizeof (struct malloc_chunk)
4790	+ psm1) & ~psm1);
4791
4792	assert ((char ) chunk2mem (p) + `4` SIZE_SZ <= paligned_mem);
4793	assert ((char *) p + size > paligned_mem);
4794
4795	/ This is the size we could potentially free. /
4796	size -= paligned_mem - (char *) p;
4797
4798	if (size > psm1)
4799	{
4800	#if MALLOC_DEBUG
4801	/ When debugging we simulate destroying the memory*
4802	content. /*
4803	memset (paligned_mem, `0x89`, size & ~psm1);
4804	#endif
4805	__madvise (paligned_mem, size & ~psm1, MADV_DONTNEED);
4806
4807	result = `1`;
4808	}
4809	}
4810	}
4811	}
4812
4813	#ifndef MORECORE_CANNOT_TRIM
4814	return result \| (av == &main_arena ? systrim (pad, av) : `0`);
4815
4816	#else
4817	return result;
4818	#endif
4819	}
4820
4821
4822	int
4823	__malloc_trim (size_t s)
4824	{
4825	int result = `0`;
4826
4827	if (__malloc_initialized < `0`)
4828	ptmalloc_init ();
4829
4830	mstate ar_ptr = &main_arena;
4831	do
4832	{
4833	__libc_lock_lock (ar_ptr->mutex);
4834	result \|= mtrim (ar_ptr, s);
4835	__libc_lock_unlock (ar_ptr->mutex);
4836
4837	ar_ptr = ar_ptr->next;
4838	}
4839	while (ar_ptr != &main_arena);
4840
4841	return result;
4842	}
4843
4844
4845	/*
4846	------------------------- malloc_usable_size -------------------------
4847	*/
4848
4849	static size_t
4850	musable (void *mem)
4851	{
4852	mchunkptr p;
4853	if (mem != `0`)
4854	{
4855	p = mem2chunk (mem);
4856
4857	if (__builtin_expect (using_malloc_checking == `1`, `0`))
4858	return malloc_check_get_size (p);
4859
4860	if (chunk_is_mmapped (p))
4861	{
4862	if (DUMPED_MAIN_ARENA_CHUNK (p))
4863	return chunksize (p) - SIZE_SZ;
4864	else
4865	return chunksize (p) - `2` * SIZE_SZ;
4866	}
4867	else if (inuse (p))
4868	return chunksize (p) - SIZE_SZ;
4869	}
4870	return `0`;
4871	}
4872
4873
4874	size_t
4875	__malloc_usable_size (void *m)
4876	{
4877	size_t result;
4878
4879	result = musable (m);
4880	return result;
4881	}
4882
4883	/*
4884	------------------------------ mallinfo ------------------------------
4885	Accumulate malloc statistics for arena AV into M.
4886	*/
4887
4888	static void
4889	int_mallinfo (mstate av, struct mallinfo *m)
4890	{
4891	size_t i;
4892	mbinptr b;
4893	mchunkptr p;
4894	INTERNAL_SIZE_T avail;
4895	INTERNAL_SIZE_T fastavail;
4896	int nblocks;
4897	int nfastblocks;
4898
4899	check_malloc_state (av);
4900
4901	/ Account for top /
4902	avail = chunksize (av->top);
4903	nblocks = `1`; / top always exists /
4904
4905	/ traverse fastbins /
4906	nfastblocks = `0`;
4907	fastavail = `0`;
4908
4909	for (i = `0`; i < NFASTBINS; ++i)
4910	{
4911	for (p = fastbin (av, i); p != `0`; p = p->fd)
4912	{
4913	++nfastblocks;
4914	fastavail += chunksize (p);
4915	}
4916	}
4917
4918	avail += fastavail;
4919
4920	/ traverse regular bins /
4921	for (i = `1`; i < NBINS; ++i)
4922	{
4923	b = bin_at (av, i);
4924	for (p = last (b); p != b; p = p->bk)
4925	{
4926	++nblocks;
4927	avail += chunksize (p);
4928	}
4929	}
4930
4931	m->smblks += nfastblocks;
4932	m->ordblks += nblocks;
4933	m->fordblks += avail;
4934	m->uordblks += av->system_mem - avail;
4935	m->arena += av->system_mem;
4936	m->fsmblks += fastavail;
4937	if (av == &main_arena)
4938	{
4939	m->hblks = mp_.n_mmaps;
4940	m->hblkhd = mp_.mmapped_mem;
4941	m->usmblks = `0`;
4942	m->keepcost = chunksize (av->top);
4943	}
4944	}
4945
4946
4947	struct mallinfo
4948	__libc_mallinfo (void)
4949	{
4950	struct mallinfo m;
4951	mstate ar_ptr;
4952
4953	if (__malloc_initialized < `0`)
4954	ptmalloc_init ();
4955
4956	memset (&m, `0`, sizeof (m));
4957	ar_ptr = &main_arena;
4958	do
4959	{
4960	__libc_lock_lock (ar_ptr->mutex);
4961	int_mallinfo (ar_ptr, &m);
4962	__libc_lock_unlock (ar_ptr->mutex);
4963
4964	ar_ptr = ar_ptr->next;
4965	}
4966	while (ar_ptr != &main_arena);
4967
4968	return m;
4969	}
4970
4971	/*
4972	------------------------------ malloc_stats ------------------------------
4973	*/
4974
4975	void
4976	__malloc_stats (void)
4977	{
4978	int i;
4979	mstate ar_ptr;
4980	unsigned int in_use_b = mp_.mmapped_mem, system_b = in_use_b;
4981
4982	if (__malloc_initialized < `0`)
4983	ptmalloc_init ();
4984	_IO_flockfile (stderr);
4985	int old_flags2 = stderr->_flags2;
4986	stderr->_flags2 \|= _IO_FLAGS2_NOTCANCEL;
4987	for (i = `0`, ar_ptr = &main_arena;; i++)
4988	{
4989	struct mallinfo mi;
4990
4991	memset (&mi, `0`, sizeof (mi));
4992	__libc_lock_lock (ar_ptr->mutex);
4993	int_mallinfo (ar_ptr, &mi);
4994	fprintf (stderr, "Arena %d:\n", i);
4995	fprintf (stderr, "system bytes = %10u\n", (unsigned int) mi.arena);
4996	fprintf (stderr, "in use bytes = %10u\n", (unsigned int) mi.uordblks);
4997	#if MALLOC_DEBUG > 1
4998	if (i > `0`)
4999	dump_heap (heap_for_ptr (top (ar_ptr)));
5000	#endif
5001	system_b += mi.arena;
5002	in_use_b += mi.uordblks;
5003	__libc_lock_unlock (ar_ptr->mutex);
5004	ar_ptr = ar_ptr->next;
5005	if (ar_ptr == &main_arena)
5006	break;
5007	}
5008	fprintf (stderr, "Total (incl. mmap):\n");
5009	fprintf (stderr, "system bytes = %10u\n", system_b);
5010	fprintf (stderr, "in use bytes = %10u\n", in_use_b);
5011	fprintf (stderr, "max mmap regions = %10u\n", (unsigned int) mp_.max_n_mmaps);
5012	fprintf (stderr, "max mmap bytes = %10lu\n",
5013	(unsigned long) mp_.max_mmapped_mem);
5014	stderr->_flags2 = old_flags2;
5015	_IO_funlockfile (stderr);
5016	}
5017
5018
5019	/*
5020	------------------------------ mallopt ------------------------------
5021	*/
5022	static inline int
5023	__always_inline
5024	do_set_trim_threshold (size_t value)
5025	{
5026	LIBC_PROBE (memory_mallopt_trim_threshold, `3`, value, mp_.trim_threshold,
5027	mp_.no_dyn_threshold);
5028	mp_.trim_threshold = value;
5029	mp_.no_dyn_threshold = `1`;
5030	return `1`;
5031	}
5032
5033	static inline int
5034	__always_inline
5035	do_set_top_pad (size_t value)
5036	{
5037	LIBC_PROBE (memory_mallopt_top_pad, `3`, value, mp_.top_pad,
5038	mp_.no_dyn_threshold);
5039	mp_.top_pad = value;
5040	mp_.no_dyn_threshold = `1`;
5041	return `1`;
5042	}
5043
5044	static inline int
5045	__always_inline
5046	do_set_mmap_threshold (size_t value)
5047	{
5048	/ Forbid setting the threshold too high. /
5049	if (value <= HEAP_MAX_SIZE / `2`)
5050	{
5051	LIBC_PROBE (memory_mallopt_mmap_threshold, `3`, value, mp_.mmap_threshold,
5052	mp_.no_dyn_threshold);
5053	mp_.mmap_threshold = value;
5054	mp_.no_dyn_threshold = `1`;
5055	return `1`;
5056	}
5057	return `0`;
5058	}
5059
5060	static inline int
5061	__always_inline
5062	do_set_mmaps_max (int32_t value)
5063	{
5064	LIBC_PROBE (memory_mallopt_mmap_max, `3`, value, mp_.n_mmaps_max,
5065	mp_.no_dyn_threshold);
5066	mp_.n_mmaps_max = value;
5067	mp_.no_dyn_threshold = `1`;
5068	return `1`;
5069	}
5070
5071	static inline int
5072	__always_inline
5073	do_set_mallopt_check (int32_t value)
5074	{
5075	return `1`;
5076	}
5077
5078	static inline int
5079	__always_inline
5080	do_set_perturb_byte (int32_t value)
5081	{
5082	LIBC_PROBE (memory_mallopt_perturb, `2`, value, perturb_byte);
5083	perturb_byte = value;
5084	return `1`;
5085	}
5086
5087	static inline int
5088	__always_inline
5089	do_set_arena_test (size_t value)
5090	{
5091	LIBC_PROBE (memory_mallopt_arena_test, `2`, value, mp_.arena_test);
5092	mp_.arena_test = value;
5093	return `1`;
5094	}
5095
5096	static inline int
5097	__always_inline
5098	do_set_arena_max (size_t value)
5099	{
5100	LIBC_PROBE (memory_mallopt_arena_max, `2`, value, mp_.arena_max);
5101	mp_.arena_max = value;
5102	return `1`;
5103	}
5104
5105	#if USE_TCACHE
5106	static inline int
5107	__always_inline
5108	do_set_tcache_max (size_t value)
5109	{
5110	if (value >= `0` && value <= MAX_TCACHE_SIZE)
5111	{
5112	LIBC_PROBE (memory_tunable_tcache_max_bytes, `2`, value, mp_.tcache_max_bytes);
5113	mp_.tcache_max_bytes = value;
5114	mp_.tcache_bins = csize2tidx (request2size(value)) + `1`;
5115	}
5116	return `1`;
5117	}
5118
5119	static inline int
5120	__always_inline
5121	do_set_tcache_count (size_t value)
5122	{
5123	LIBC_PROBE (memory_tunable_tcache_count, `2`, value, mp_.tcache_count);
5124	mp_.tcache_count = value;
5125	return `1`;
5126	}
5127
5128	static inline int
5129	__always_inline
5130	do_set_tcache_unsorted_limit (size_t value)
5131	{
5132	LIBC_PROBE (memory_tunable_tcache_unsorted_limit, `2`, value, mp_.tcache_unsorted_limit);
5133	mp_.tcache_unsorted_limit = value;
5134	return `1`;
5135	}
5136	#endif
5137
5138	int
5139	__libc_mallopt (int param_number, int value)
5140	{
5141	mstate av = &main_arena;
5142	int res = `1`;
5143
5144	if (__malloc_initialized < `0`)
5145	ptmalloc_init ();
5146	__libc_lock_lock (av->mutex);
5147
5148	LIBC_PROBE (memory_mallopt, `2`, param_number, value);
5149
5150	/ We must consolidate main arena before changing max_fast*
5151	(see definition of set_max_fast). /*
5152	malloc_consolidate (av);
5153
5154	switch (param_number)
5155	{
5156	case M_MXFAST:
5157	if (value >= `0` && value <= MAX_FAST_SIZE)
5158	{
5159	LIBC_PROBE (memory_mallopt_mxfast, `2`, value, get_max_fast ());
5160	set_max_fast (value);
5161	}
5162	else
5163	res = `0`;
5164	break;
5165
5166	case M_TRIM_THRESHOLD:
5167	do_set_trim_threshold (value);
5168	break;
5169
5170	case M_TOP_PAD:
5171	do_set_top_pad (value);
5172	break;
5173
5174	case M_MMAP_THRESHOLD:
5175	res = do_set_mmap_threshold (value);
5176	break;
5177
5178	case M_MMAP_MAX:
5179	do_set_mmaps_max (value);
5180	break;
5181
5182	case M_CHECK_ACTION:
5183	do_set_mallopt_check (value);
5184	break;
5185
5186	case M_PERTURB:
5187	do_set_perturb_byte (value);
5188	break;
5189
5190	case M_ARENA_TEST:
5191	if (value > `0`)
5192	do_set_arena_test (value);
5193	break;
5194
5195	case M_ARENA_MAX:
5196	if (value > `0`)
5197	do_set_arena_max (value);
5198	break;
5199	}
5200	__libc_lock_unlock (av->mutex);
5201	return res;
5202	}
5203	libc_hidden_def (__libc_mallopt)
5204
5205
5206	/*
5207	-------------------- Alternative MORECORE functions --------------------
5208	*/
5209
5210
5211	/*
5212	General Requirements for MORECORE.
5213
5214	The MORECORE function must have the following properties:
5215
5216	If MORECORE_CONTIGUOUS is false:
5217
5218	* MORECORE must allocate in multiples of pagesize. It will
5219	only be called with arguments that are multiples of pagesize.
5220
5221	* MORECORE(0) must return an address that is at least
5222	MALLOC_ALIGNMENT aligned. (Page-aligning always suffices.)
5223
5224	else (i.e. If MORECORE_CONTIGUOUS is true):
5225
5226	* Consecutive calls to MORECORE with positive arguments
5227	return increasing addresses, indicating that space has been
5228	contiguously extended.
5229
5230	* MORECORE need not allocate in multiples of pagesize.
5231	Calls to MORECORE need not have args of multiples of pagesize.
5232
5233	* MORECORE need not page-align.
5234
5235	In either case:
5236
5237	* MORECORE may allocate more memory than requested. (Or even less,
5238	but this will generally result in a malloc failure.)
5239
5240	* MORECORE must not allocate memory when given argument zero, but
5241	instead return one past the end address of memory from previous
5242	nonzero call. This malloc does NOT call MORECORE(0)
5243	until at least one call with positive arguments is made, so
5244	the initial value returned is not important.
5245
5246	* Even though consecutive calls to MORECORE need not return contiguous
5247	addresses, it must be OK for malloc'ed chunks to span multiple
5248	regions in those cases where they do happen to be contiguous.
5249
5250	* MORECORE need not handle negative arguments -- it may instead
5251	just return MORECORE_FAILURE when given negative arguments.
5252	Negative arguments are always multiples of pagesize. MORECORE
5253	must not misinterpret negative args as large positive unsigned
5254	args. You can suppress all such calls from even occurring by defining
5255	MORECORE_CANNOT_TRIM,
5256
5257	There is some variation across systems about the type of the
5258	argument to sbrk/MORECORE. If size_t is unsigned, then it cannot
5259	actually be size_t, because sbrk supports negative args, so it is
5260	normally the signed type of the same width as size_t (sometimes
5261	declared as "intptr_t", and sometimes "ptrdiff_t"). It doesn't much
5262	matter though. Internally, we use "long" as arguments, which should
5263	work across all reasonable possibilities.
5264
5265	Additionally, if MORECORE ever returns failure for a positive
5266	request, then mmap is used as a noncontiguous system allocator. This
5267	is a useful backup strategy for systems with holes in address spaces
5268	-- in this case sbrk cannot contiguously expand the heap, but mmap
5269	may be able to map noncontiguous space.
5270
5271	If you'd like mmap to ALWAYS be used, you can define MORECORE to be
5272	a function that always returns MORECORE_FAILURE.
5273
5274	If you are using this malloc with something other than sbrk (or its
5275	emulation) to supply memory regions, you probably want to set
5276	MORECORE_CONTIGUOUS as false. As an example, here is a custom
5277	allocator kindly contributed for pre-OSX macOS. It uses virtually
5278	but not necessarily physically contiguous non-paged memory (locked
5279	in, present and won't get swapped out). You can use it by
5280	uncommenting this section, adding some #includes, and setting up the
5281	appropriate defines above:
5282
5283	*#define MORECORE osMoreCore
5284	*#define MORECORE_CONTIGUOUS 0
5285
5286	There is also a shutdown routine that should somehow be called for
5287	cleanup upon program exit.
5288
5289	*#define MAX_POOL_ENTRIES 100
5290	#define MINIMUM_MORECORE_SIZE (64 1024)
5291	static int next_os_pool;
5292	void our_os_pools[MAX_POOL_ENTRIES];*
5293
5294	void osMoreCore(int size)*
5295	{
5296	void ptr = 0;*
5297	static void sbrk_top = 0;*
5298
5299	if (size > 0)
5300	{
5301	if (size < MINIMUM_MORECORE_SIZE)
5302	size = MINIMUM_MORECORE_SIZE;
5303	if (CurrentExecutionLevel() == kTaskLevel)
5304	ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
5305	if (ptr == 0)
5306	{
5307	return (void ) MORECORE_FAILURE;*
5308	}
5309	// save ptrs so they can be freed during cleanup
5310	our_os_pools[next_os_pool] = ptr;
5311	next_os_pool++;
5312	ptr = (void ) ((((unsigned long) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);*
5313	sbrk_top = (char ) ptr + size;*
5314	return ptr;
5315	}
5316	else if (size < 0)
5317	{
5318	// we don't currently support shrink behavior
5319	return (void ) MORECORE_FAILURE;*
5320	}
5321	else
5322	{
5323	return sbrk_top;
5324	}
5325	}
5326
5327	// cleanup any allocated memory pools
5328	// called as last thing before shutting down driver
5329
5330	void osCleanupMem(void)
5331	{
5332	void ptr;
5333
5334	for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
5335	if (ptr)*
5336	{
5337	PoolDeallocate(ptr);*
5338	* ptr = 0;
5339	}
5340	}
5341
5342	*/
5343
5344
5345	/ Helper code. /
5346
5347	extern char **__libc_argv attribute_hidden;
5348
5349	static void
5350	malloc_printerr (const char *str)
5351	{
5352	__libc_message (do_abort, "%s\n", str);
5353	__builtin_unreachable ();
5354	}
5355
5356	/ We need a wrapper function for one of the additions of POSIX. /
5357	int
5358	__posix_memalign (void **memptr, size_t alignment, size_t size)
5359	{
5360	void *mem;
5361
5362	/ Test whether the SIZE argument is valid. It must be a power of*
5363	two multiple of sizeof (void ). /
5364	if (alignment % sizeof (void *) != `0`
5365	\|\| !powerof2 (alignment / sizeof (void *))
5366	\|\| alignment == `0`)
5367	return EINVAL;
5368
5369
5370	void *address = RETURN_ADDRESS (`0`);
5371	mem = _mid_memalign (alignment, size, address);
5372
5373	if (mem != NULL)
5374	{
5375	*memptr = mem;
5376	return `0`;
5377	}
5378
5379	return ENOMEM;
5380	}
5381	weak_alias (__posix_memalign, posix_memalign)
5382
5383
5384	int
5385	__malloc_info (int options, FILE *fp)
5386	{
5387	/ For now, at least. /
5388	if (options != `0`)
5389	return EINVAL;
5390
5391	int n = `0`;
5392	size_t total_nblocks = `0`;
5393	size_t total_nfastblocks = `0`;
5394	size_t total_avail = `0`;
5395	size_t total_fastavail = `0`;
5396	size_t total_system = `0`;
5397	size_t total_max_system = `0`;
5398	size_t total_aspace = `0`;
5399	size_t total_aspace_mprotect = `0`;
5400
5401
5402
5403	if (__malloc_initialized < `0`)
5404	ptmalloc_init ();
5405
5406	fputs ("<malloc version=\"1\">\n", fp);
5407
5408	/ Iterate over all arenas currently in use. /
5409	mstate ar_ptr = &main_arena;
5410	do
5411	{
5412	fprintf (fp, "<heap nr=\"%d\">\n<sizes>\n", n++);
5413
5414	size_t nblocks = `0`;
5415	size_t nfastblocks = `0`;
5416	size_t avail = `0`;
5417	size_t fastavail = `0`;
5418	struct
5419	{
5420	size_t from;
5421	size_t to;
5422	size_t total;
5423	size_t count;
5424	} sizes[NFASTBINS + NBINS - `1`];
5425	#define nsizes (sizeof (sizes) / sizeof (sizes[0]))
5426
5427	__libc_lock_lock (ar_ptr->mutex);
5428
5429	for (size_t i = `0`; i < NFASTBINS; ++i)
5430	{
5431	mchunkptr p = fastbin (ar_ptr, i);
5432	if (p != NULL)
5433	{
5434	size_t nthissize = `0`;
5435	size_t thissize = chunksize (p);
5436
5437	while (p != NULL)
5438	{
5439	++nthissize;
5440	p = p->fd;
5441	}
5442
5443	fastavail += nthissize * thissize;
5444	nfastblocks += nthissize;
5445	sizes[i].from = thissize - (MALLOC_ALIGNMENT - `1`);
5446	sizes[i].to = thissize;
5447	sizes[i].count = nthissize;
5448	}
5449	else
5450	sizes[i].from = sizes[i].to = sizes[i].count = `0`;
5451
5452	sizes[i].total = sizes[i].count * sizes[i].to;
5453	}
5454
5455
5456	mbinptr bin;
5457	struct malloc_chunk *r;
5458
5459	for (size_t i = `1`; i < NBINS; ++i)
5460	{
5461	bin = bin_at (ar_ptr, i);
5462	r = bin->fd;
5463	sizes[NFASTBINS - `1` + i].from = ~((size_t) `0`);
5464	sizes[NFASTBINS - `1` + i].to = sizes[NFASTBINS - `1` + i].total
5465	= sizes[NFASTBINS - `1` + i].count = `0`;
5466
5467	if (r != NULL)
5468	while (r != bin)
5469	{
5470	size_t r_size = chunksize_nomask (r);
5471	++sizes[NFASTBINS - `1` + i].count;
5472	sizes[NFASTBINS - `1` + i].total += r_size;
5473	sizes[NFASTBINS - `1` + i].from
5474	= MIN (sizes[NFASTBINS - `1` + i].from, r_size);
5475	sizes[NFASTBINS - `1` + i].to = MAX (sizes[NFASTBINS - `1` + i].to,
5476	r_size);
5477
5478	r = r->fd;
5479	}
5480
5481	if (sizes[NFASTBINS - `1` + i].count == `0`)
5482	sizes[NFASTBINS - `1` + i].from = `0`;
5483	nblocks += sizes[NFASTBINS - `1` + i].count;
5484	avail += sizes[NFASTBINS - `1` + i].total;
5485	}
5486
5487	size_t heap_size = `0`;
5488	size_t heap_mprotect_size = `0`;
5489	size_t heap_count = `0`;
5490	if (ar_ptr != &main_arena)
5491	{
5492	/ Iterate over the arena heaps from back to front. /
5493	heap_info *heap = heap_for_ptr (top (ar_ptr));
5494	do
5495	{
5496	heap_size += heap->size;
5497	heap_mprotect_size += heap->mprotect_size;
5498	heap = heap->prev;
5499	++heap_count;
5500	}
5501	while (heap != NULL);
5502	}
5503
5504	__libc_lock_unlock (ar_ptr->mutex);
5505
5506	total_nfastblocks += nfastblocks;
5507	total_fastavail += fastavail;
5508
5509	total_nblocks += nblocks;
5510	total_avail += avail;
5511
5512	for (size_t i = `0`; i < nsizes; ++i)
5513	if (sizes[i].count != `0` && i != NFASTBINS)
5514	fprintf (fp, " \
5515	<size from=\"%zu\" to=\"%zu\" total=\"%zu\" count=\"%zu\"/>\n",
5516	sizes[i].from, sizes[i].to, sizes[i].total, sizes[i].count);
5517
5518	if (sizes[NFASTBINS].count != `0`)
5519	fprintf (fp, "\
5520	<unsorted from=\"%zu\" to=\"%zu\" total=\"%zu\" count=\"%zu\"/>\n",
5521	sizes[NFASTBINS].from, sizes[NFASTBINS].to,
5522	sizes[NFASTBINS].total, sizes[NFASTBINS].count);
5523
5524	total_system += ar_ptr->system_mem;
5525	total_max_system += ar_ptr->max_system_mem;
5526
5527	fprintf (fp,
5528	"</sizes>\n<total type=\"fast\" count=\"%zu\" size=\"%zu\"/>\n"
5529	"<total type=\"rest\" count=\"%zu\" size=\"%zu\"/>\n"
5530	"<system type=\"current\" size=\"%zu\"/>\n"
5531	"<system type=\"max\" size=\"%zu\"/>\n",
5532	nfastblocks, fastavail, nblocks, avail,
5533	ar_ptr->system_mem, ar_ptr->max_system_mem);
5534
5535	if (ar_ptr != &main_arena)
5536	{
5537	fprintf (fp,
5538	"<aspace type=\"total\" size=\"%zu\"/>\n"
5539	"<aspace type=\"mprotect\" size=\"%zu\"/>\n"
5540	"<aspace type=\"subheaps\" size=\"%zu\"/>\n",
5541	heap_size, heap_mprotect_size, heap_count);
5542	total_aspace += heap_size;
5543	total_aspace_mprotect += heap_mprotect_size;
5544	}
5545	else
5546	{
5547	fprintf (fp,
5548	"<aspace type=\"total\" size=\"%zu\"/>\n"
5549	"<aspace type=\"mprotect\" size=\"%zu\"/>\n",
5550	ar_ptr->system_mem, ar_ptr->system_mem);
5551	total_aspace += ar_ptr->system_mem;
5552	total_aspace_mprotect += ar_ptr->system_mem;
5553	}
5554
5555	fputs ("</heap>\n", fp);
5556	ar_ptr = ar_ptr->next;
5557	}
5558	while (ar_ptr != &main_arena);
5559
5560	fprintf (fp,
5561	"<total type=\"fast\" count=\"%zu\" size=\"%zu\"/>\n"
5562	"<total type=\"rest\" count=\"%zu\" size=\"%zu\"/>\n"
5563	"<total type=\"mmap\" count=\"%d\" size=\"%zu\"/>\n"
5564	"<system type=\"current\" size=\"%zu\"/>\n"
5565	"<system type=\"max\" size=\"%zu\"/>\n"
5566	"<aspace type=\"total\" size=\"%zu\"/>\n"
5567	"<aspace type=\"mprotect\" size=\"%zu\"/>\n"
5568	"</malloc>\n",
5569	total_nfastblocks, total_fastavail, total_nblocks, total_avail,
5570	mp_.n_mmaps, mp_.mmapped_mem,
5571	total_system, total_max_system,
5572	total_aspace, total_aspace_mprotect);
5573
5574	return `0`;
5575	}
5576	weak_alias (__malloc_info, malloc_info)
5577
5578
5579	strong_alias (__libc_calloc, __calloc) weak_alias (__libc_calloc, calloc)
5580	strong_alias (__libc_free, __free) strong_alias (__libc_free, free)
5581	strong_alias (__libc_malloc, __malloc) strong_alias (__libc_malloc, malloc)
5582	strong_alias (__libc_memalign, __memalign)
5583	weak_alias (__libc_memalign, memalign)
5584	strong_alias (__libc_realloc, __realloc) strong_alias (__libc_realloc, realloc)
5585	strong_alias (__libc_valloc, __valloc) weak_alias (__libc_valloc, valloc)
5586	strong_alias (__libc_pvalloc, __pvalloc) weak_alias (__libc_pvalloc, pvalloc)
5587	strong_alias (__libc_mallinfo, __mallinfo)
5588	weak_alias (__libc_mallinfo, mallinfo)
5589	strong_alias (__libc_mallopt, __mallopt) weak_alias (__libc_mallopt, mallopt)
5590
5591	weak_alias (__malloc_stats, malloc_stats)
5592	weak_alias (__malloc_usable_size, malloc_usable_size)
5593	weak_alias (__malloc_trim, malloc_trim)
5594
5595	#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_26)
5596	compat_symbol (libc, __libc_free, cfree, GLIBC_2_0);
5597	#endif
5598
5599	/ ------------------------------------------------------------*
5600	History:
5601
5602	[see ftp://g.oswego.edu/pub/misc/malloc.c for the history of dlmalloc]
5603
5604	*/
5605	/*
5606	* Local variables:
5607	* c-basic-offset: 2
5608	* End:
5609	*/
5610

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