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

1	/ Malloc implementation for multiple threads without lock contention.*
2	Copyright (C) 1996-2018 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	/ Take a chunk off a bin list /
1388	#define unlink(AV, P, BK, FD) { \
1389	if (__builtin_expect (chunksize(P) != prev_size (next_chunk(P)), 0)) \
1390	malloc_printerr ("corrupted size vs. prev_size"); \
1391	FD = P->fd; \
1392	BK = P->bk; \
1393	if (__builtin_expect (FD->bk != P \|\| BK->fd != P, 0)) \
1394	malloc_printerr ("corrupted double-linked list"); \
1395	else { \
1396	FD->bk = BK; \
1397	BK->fd = FD; \
1398	if (!in_smallbin_range (chunksize_nomask (P)) \
1399	&& __builtin_expect (P->fd_nextsize != NULL, 0)) { \
1400	if (__builtin_expect (P->fd_nextsize->bk_nextsize != P, 0) \
1401	\|\| __builtin_expect (P->bk_nextsize->fd_nextsize != P, 0)) \
1402	malloc_printerr ("corrupted double-linked list (not small)"); \
1403	if (FD->fd_nextsize == NULL) { \
1404	if (P->fd_nextsize == P) \
1405	FD->fd_nextsize = FD->bk_nextsize = FD; \
1406	else { \
1407	FD->fd_nextsize = P->fd_nextsize; \
1408	FD->bk_nextsize = P->bk_nextsize; \
1409	P->fd_nextsize->bk_nextsize = FD; \
1410	P->bk_nextsize->fd_nextsize = FD; \
1411	} \
1412	} else { \
1413	P->fd_nextsize->bk_nextsize = P->bk_nextsize; \
1414	P->bk_nextsize->fd_nextsize = P->fd_nextsize; \
1415	} \
1416	} \
1417	} \
1418	}
1419
1420	/*
1421	Indexing
1422
1423	Bins for sizes < 512 bytes contain chunks of all the same size, spaced
1424	8 bytes apart. Larger bins are approximately logarithmically spaced:
1425
1426	64 bins of size 8
1427	32 bins of size 64
1428	16 bins of size 512
1429	8 bins of size 4096
1430	4 bins of size 32768
1431	2 bins of size 262144
1432	1 bin of size what's left
1433
1434	There is actually a little bit of slop in the numbers in bin_index
1435	for the sake of speed. This makes no difference elsewhere.
1436
1437	The bins top out around 1MB because we expect to service large
1438	requests via mmap.
1439
1440	Bin 0 does not exist. Bin 1 is the unordered list; if that would be
1441	a valid chunk size the small bins are bumped up one.
1442	*/
1443
1444	#define NBINS 128
1445	#define NSMALLBINS 64
1446	#define SMALLBIN_WIDTH MALLOC_ALIGNMENT
1447	#define SMALLBIN_CORRECTION (MALLOC_ALIGNMENT > 2 * SIZE_SZ)
1448	#define MIN_LARGE_SIZE ((NSMALLBINS - SMALLBIN_CORRECTION) * SMALLBIN_WIDTH)
1449
1450	#define in_smallbin_range(sz) \
1451	((unsigned long) (sz) < (unsigned long) MIN_LARGE_SIZE)
1452
1453	#define smallbin_index(sz) \
1454	((SMALLBIN_WIDTH == 16 ? (((unsigned) (sz)) >> 4) : (((unsigned) (sz)) >> 3))\
1455	+ SMALLBIN_CORRECTION)
1456
1457	#define largebin_index_32(sz) \
1458	(((((unsigned long) (sz)) >> 6) <= 38) ? 56 + (((unsigned long) (sz)) >> 6) :\
1459	((((unsigned long) (sz)) >> 9) <= 20) ? 91 + (((unsigned long) (sz)) >> 9) :\
1460	((((unsigned long) (sz)) >> 12) <= 10) ? 110 + (((unsigned long) (sz)) >> 12) :\
1461	((((unsigned long) (sz)) >> 15) <= 4) ? 119 + (((unsigned long) (sz)) >> 15) :\
1462	((((unsigned long) (sz)) >> 18) <= 2) ? 124 + (((unsigned long) (sz)) >> 18) :\
1463	126)
1464
1465	#define largebin_index_32_big(sz) \
1466	(((((unsigned long) (sz)) >> 6) <= 45) ? 49 + (((unsigned long) (sz)) >> 6) :\
1467	((((unsigned long) (sz)) >> 9) <= 20) ? 91 + (((unsigned long) (sz)) >> 9) :\
1468	((((unsigned long) (sz)) >> 12) <= 10) ? 110 + (((unsigned long) (sz)) >> 12) :\
1469	((((unsigned long) (sz)) >> 15) <= 4) ? 119 + (((unsigned long) (sz)) >> 15) :\
1470	((((unsigned long) (sz)) >> 18) <= 2) ? 124 + (((unsigned long) (sz)) >> 18) :\
1471	126)
1472
1473	// XXX It remains to be seen whether it is good to keep the widths of
1474	// XXX the buckets the same or whether it should be scaled by a factor
1475	// XXX of two as well.
1476	#define largebin_index_64(sz) \
1477	(((((unsigned long) (sz)) >> 6) <= 48) ? 48 + (((unsigned long) (sz)) >> 6) :\
1478	((((unsigned long) (sz)) >> 9) <= 20) ? 91 + (((unsigned long) (sz)) >> 9) :\
1479	((((unsigned long) (sz)) >> 12) <= 10) ? 110 + (((unsigned long) (sz)) >> 12) :\
1480	((((unsigned long) (sz)) >> 15) <= 4) ? 119 + (((unsigned long) (sz)) >> 15) :\
1481	((((unsigned long) (sz)) >> 18) <= 2) ? 124 + (((unsigned long) (sz)) >> 18) :\
1482	126)
1483
1484	#define largebin_index(sz) \
1485	(SIZE_SZ == 8 ? largebin_index_64 (sz) \
1486	: MALLOC_ALIGNMENT == 16 ? largebin_index_32_big (sz) \
1487	: largebin_index_32 (sz))
1488
1489	#define bin_index(sz) \
1490	((in_smallbin_range (sz)) ? smallbin_index (sz) : largebin_index (sz))
1491
1492
1493	/*
1494	Unsorted chunks
1495
1496	All remainders from chunk splits, as well as all returned chunks,
1497	are first placed in the "unsorted" bin. They are then placed
1498	in regular bins after malloc gives them ONE chance to be used before
1499	binning. So, basically, the unsorted_chunks list acts as a queue,
1500	with chunks being placed on it in free (and malloc_consolidate),
1501	and taken off (to be either used or placed in bins) in malloc.
1502
1503	The NON_MAIN_ARENA flag is never set for unsorted chunks, so it
1504	does not have to be taken into account in size comparisons.
1505	*/
1506
1507	/ The otherwise unindexable 1-bin is used to hold unsorted chunks. /
1508	#define unsorted_chunks(M) (bin_at (M, 1))
1509
1510	/*
1511	Top
1512
1513	The top-most available chunk (i.e., the one bordering the end of
1514	available memory) is treated specially. It is never included in
1515	any bin, is used only if no other chunk is available, and is
1516	released back to the system if it is very large (see
1517	M_TRIM_THRESHOLD). Because top initially
1518	points to its own bin with initial zero size, thus forcing
1519	extension on the first malloc request, we avoid having any special
1520	code in malloc to check whether it even exists yet. But we still
1521	need to do so when getting memory from system, so we make
1522	initial_top treat the bin as a legal but unusable chunk during the
1523	interval between initialization and the first call to
1524	sysmalloc. (This is somewhat delicate, since it relies on
1525	the 2 preceding words to be zero during this interval as well.)
1526	*/
1527
1528	/ Conveniently, the unsorted bin can be used as dummy top on first call /
1529	#define initial_top(M) (unsorted_chunks (M))
1530
1531	/*
1532	Binmap
1533
1534	To help compensate for the large number of bins, a one-level index
1535	structure is used for bin-by-bin searching. `binmap' is a
1536	bitvector recording whether bins are definitely empty so they can
1537	be skipped over during during traversals. The bits are NOT always
1538	cleared as soon as bins are empty, but instead only
1539	when they are noticed to be empty during traversal in malloc.
1540	*/
1541
1542	/ Conservatively use 32 bits per map word, even if on 64bit system /
1543	#define BINMAPSHIFT 5
1544	#define BITSPERMAP (1U << BINMAPSHIFT)
1545	#define BINMAPSIZE (NBINS / BITSPERMAP)
1546
1547	#define idx2block(i) ((i) >> BINMAPSHIFT)
1548	#define idx2bit(i) ((1U << ((i) & ((1U << BINMAPSHIFT) - 1))))
1549
1550	#define mark_bin(m, i) ((m)->binmap[idx2block (i)] \|= idx2bit (i))
1551	#define unmark_bin(m, i) ((m)->binmap[idx2block (i)] &= ~(idx2bit (i)))
1552	#define get_binmap(m, i) ((m)->binmap[idx2block (i)] & idx2bit (i))
1553
1554	/*
1555	Fastbins
1556
1557	An array of lists holding recently freed small chunks. Fastbins
1558	are not doubly linked. It is faster to single-link them, and
1559	since chunks are never removed from the middles of these lists,
1560	double linking is not necessary. Also, unlike regular bins, they
1561	are not even processed in FIFO order (they use faster LIFO) since
1562	ordering doesn't much matter in the transient contexts in which
1563	fastbins are normally used.
1564
1565	Chunks in fastbins keep their inuse bit set, so they cannot
1566	be consolidated with other free chunks. malloc_consolidate
1567	releases all chunks in fastbins and consolidates them with
1568	other free chunks.
1569	*/
1570
1571	typedef struct malloc_chunk *mfastbinptr;
1572	#define fastbin(ar_ptr, idx) ((ar_ptr)->fastbinsY[idx])
1573
1574	/ offset 2 to use otherwise unindexable first 2 bins /
1575	#define fastbin_index(sz) \
1576	((((unsigned int) (sz)) >> (SIZE_SZ == 8 ? 4 : 3)) - 2)
1577
1578
1579	/ The maximum fastbin request size we support /
1580	#define MAX_FAST_SIZE (80 * SIZE_SZ / 4)
1581
1582	#define NFASTBINS (fastbin_index (request2size (MAX_FAST_SIZE)) + 1)
1583
1584	/*
1585	FASTBIN_CONSOLIDATION_THRESHOLD is the size of a chunk in free()
1586	that triggers automatic consolidation of possibly-surrounding
1587	fastbin chunks. This is a heuristic, so the exact value should not
1588	matter too much. It is defined at half the default trim threshold as a
1589	compromise heuristic to only attempt consolidation if it is likely
1590	to lead to trimming. However, it is not dynamically tunable, since
1591	consolidation reduces fragmentation surrounding large chunks even
1592	if trimming is not used.
1593	*/
1594
1595	#define FASTBIN_CONSOLIDATION_THRESHOLD (65536UL)
1596
1597	/*
1598	NONCONTIGUOUS_BIT indicates that MORECORE does not return contiguous
1599	regions. Otherwise, contiguity is exploited in merging together,
1600	when possible, results from consecutive MORECORE calls.
1601
1602	The initial value comes from MORECORE_CONTIGUOUS, but is
1603	changed dynamically if mmap is ever used as an sbrk substitute.
1604	*/
1605
1606	#define NONCONTIGUOUS_BIT (2U)
1607
1608	#define contiguous(M) (((M)->flags & NONCONTIGUOUS_BIT) == 0)
1609	#define noncontiguous(M) (((M)->flags & NONCONTIGUOUS_BIT) != 0)
1610	#define set_noncontiguous(M) ((M)->flags \|= NONCONTIGUOUS_BIT)
1611	#define set_contiguous(M) ((M)->flags &= ~NONCONTIGUOUS_BIT)
1612
1613	/ Maximum size of memory handled in fastbins. /
1614	static INTERNAL_SIZE_T global_max_fast;
1615
1616	/*
1617	Set value of max_fast.
1618	Use impossibly small value if 0.
1619	Precondition: there are no existing fastbin chunks in the main arena.
1620	Since do_check_malloc_state () checks this, we call malloc_consolidate ()
1621	before changing max_fast. Note other arenas will leak their fast bin
1622	entries if max_fast is reduced.
1623	*/
1624
1625	#define set_max_fast(s) \
1626	global_max_fast = (((s) == 0) \
1627	? SMALLBIN_WIDTH : ((s + SIZE_SZ) & ~MALLOC_ALIGN_MASK))
1628
1629	static inline INTERNAL_SIZE_T
1630	get_max_fast (void)
1631	{
1632	/ Tell the GCC optimizers that global_max_fast is never larger*
1633	than MAX_FAST_SIZE. This avoids out-of-bounds array accesses in
1634	_int_malloc after constant propagation of the size parameter.
1635	(The code never executes because malloc preserves the
1636	global_max_fast invariant, but the optimizers may not recognize
1637	this.) /*
1638	if (global_max_fast > MAX_FAST_SIZE)
1639	__builtin_unreachable ();
1640	return global_max_fast;
1641	}
1642
1643	/*
1644	----------- Internal state representation and initialization -----------
1645	*/
1646
1647	/*
1648	have_fastchunks indicates that there are probably some fastbin chunks.
1649	It is set true on entering a chunk into any fastbin, and cleared early in
1650	malloc_consolidate. The value is approximate since it may be set when there
1651	are no fastbin chunks, or it may be clear even if there are fastbin chunks
1652	available. Given it's sole purpose is to reduce number of redundant calls to
1653	malloc_consolidate, it does not affect correctness. As a result we can safely
1654	use relaxed atomic accesses.
1655	*/
1656
1657
1658	struct malloc_state
1659	{
1660	/ Serialize access. /
1661	__libc_lock_define (, mutex);
1662
1663	/ Flags (formerly in max_fast). /
1664	int flags;
1665
1666	/ Set if the fastbin chunks contain recently inserted free blocks. /
1667	/ Note this is a bool but not all targets support atomics on booleans. /
1668	int have_fastchunks;
1669
1670	/ Fastbins /
1671	mfastbinptr fastbinsY[NFASTBINS];
1672
1673	/ Base of the topmost chunk -- not otherwise kept in a bin /
1674	mchunkptr top;
1675
1676	/ The remainder from the most recent split of a small request /
1677	mchunkptr last_remainder;
1678
1679	/ Normal bins packed as described above /
1680	mchunkptr bins[NBINS * `2` - `2`];
1681
1682	/ Bitmap of bins /
1683	unsigned int binmap[BINMAPSIZE];
1684
1685	/ Linked list /
1686	struct malloc_state *next;
1687
1688	/ Linked list for free arenas. Access to this field is serialized*
1689	by free_list_lock in arena.c. /*
1690	struct malloc_state *next_free;
1691
1692	/ Number of threads attached to this arena. 0 if the arena is on*
1693	the free list. Access to this field is serialized by
1694	free_list_lock in arena.c. /*
1695	INTERNAL_SIZE_T attached_threads;
1696
1697	/ Memory allocated from the system in this arena. /
1698	INTERNAL_SIZE_T system_mem;
1699	INTERNAL_SIZE_T max_system_mem;
1700	};
1701
1702	struct malloc_par
1703	{
1704	/ Tunable parameters /
1705	unsigned long trim_threshold;
1706	INTERNAL_SIZE_T top_pad;
1707	INTERNAL_SIZE_T mmap_threshold;
1708	INTERNAL_SIZE_T arena_test;
1709	INTERNAL_SIZE_T arena_max;
1710
1711	/ Memory map support /
1712	int n_mmaps;
1713	int n_mmaps_max;
1714	int max_n_mmaps;
1715	/ the mmap_threshold is dynamic, until the user sets*
1716	it manually, at which point we need to disable any
1717	dynamic behavior. /*
1718	int no_dyn_threshold;
1719
1720	/ Statistics /
1721	INTERNAL_SIZE_T mmapped_mem;
1722	INTERNAL_SIZE_T max_mmapped_mem;
1723
1724	/ First address handed out by MORECORE/sbrk. /
1725	char *sbrk_base;
1726
1727	#if USE_TCACHE
1728	/ Maximum number of buckets to use. /
1729	size_t tcache_bins;
1730	size_t tcache_max_bytes;
1731	/ Maximum number of chunks in each bucket. /
1732	size_t tcache_count;
1733	/ Maximum number of chunks to remove from the unsorted list, which*
1734	aren't used to prefill the cache. /*
1735	size_t tcache_unsorted_limit;
1736	#endif
1737	};
1738
1739	/ There are several instances of this struct ("arenas") in this*
1740	malloc. If you are adapting this malloc in a way that does NOT use
1741	a static or mmapped malloc_state, you MUST explicitly zero-fill it
1742	before using. This malloc relies on the property that malloc_state
1743	is initialized to all zeroes (as is true of C statics). /*
1744
1745	static struct malloc_state main_arena =
1746	{
1747	.mutex = _LIBC_LOCK_INITIALIZER,
1748	.next = &main_arena,
1749	.attached_threads = `1`
1750	};
1751
1752	/ These variables are used for undumping support. Chunked are marked*
1753	as using mmap, but we leave them alone if they fall into this
1754	range. NB: The chunk size for these chunks only includes the
1755	initial size field (of SIZE_SZ bytes), there is no trailing size
1756	field (unlike with regular mmapped chunks). /*
1757	static mchunkptr dumped_main_arena_start; / Inclusive. /
1758	static mchunkptr dumped_main_arena_end; / Exclusive. /
1759
1760	/ True if the pointer falls into the dumped arena. Use this after*
1761	chunk_is_mmapped indicates a chunk is mmapped. /*
1762	#define DUMPED_MAIN_ARENA_CHUNK(p) \
1763	((p) >= dumped_main_arena_start && (p) < dumped_main_arena_end)
1764
1765	/ There is only one instance of the malloc parameters. /
1766
1767	static struct malloc_par mp_ =
1768	{
1769	.top_pad = DEFAULT_TOP_PAD,
1770	.n_mmaps_max = DEFAULT_MMAP_MAX,
1771	.mmap_threshold = DEFAULT_MMAP_THRESHOLD,
1772	.trim_threshold = DEFAULT_TRIM_THRESHOLD,
1773	#define NARENAS_FROM_NCORES(n) ((n) * (sizeof (long) == 4 ? 2 : 8))
1774	.arena_test = NARENAS_FROM_NCORES (`1`)
1775	#if USE_TCACHE
1776	,
1777	.tcache_count = TCACHE_FILL_COUNT,
1778	.tcache_bins = TCACHE_MAX_BINS,
1779	.tcache_max_bytes = tidx2usize (TCACHE_MAX_BINS-`1`),
1780	.tcache_unsorted_limit = `0` / No limit. /
1781	#endif
1782	};
1783
1784	/*
1785	Initialize a malloc_state struct.
1786
1787	This is called from ptmalloc_init () or from _int_new_arena ()
1788	when creating a new arena.
1789	*/
1790
1791	static void
1792	malloc_init_state (mstate av)
1793	{
1794	int i;
1795	mbinptr bin;
1796
1797	/ Establish circular links for normal bins /
1798	for (i = `1`; i < NBINS; ++i)
1799	{
1800	bin = bin_at (av, i);
1801	bin->fd = bin->bk = bin;
1802	}
1803
1804	#if MORECORE_CONTIGUOUS
1805	if (av != &main_arena)
1806	#endif
1807	set_noncontiguous (av);
1808	if (av == &main_arena)
1809	set_max_fast (DEFAULT_MXFAST);
1810	atomic_store_relaxed (&av->have_fastchunks, false);
1811
1812	av->top = initial_top (av);
1813	}
1814
1815	/*
1816	Other internal utilities operating on mstates
1817	*/
1818
1819	static void *sysmalloc (INTERNAL_SIZE_T, mstate);
1820	static int systrim (size_t, mstate);
1821	static void malloc_consolidate (mstate);
1822
1823
1824	/ -------------- Early definitions for debugging hooks ---------------- /
1825
1826	/ Define and initialize the hook variables. These weak definitions must*
1827	appear before any use of the variables in a function (arena.c uses one). /*
1828	#ifndef weak_variable
1829	/ In GNU libc we want the hook variables to be weak definitions to*
1830	avoid a problem with Emacs. /*
1831	# define weak_variable weak_function
1832	#endif
1833
1834	/ Forward declarations. /
1835	static void *malloc_hook_ini (size_t sz,
1836	const void *caller) __THROW;
1837	static void realloc_hook_ini (void* *ptr, size_t sz,
1838	const void *caller) __THROW;
1839	static void *memalign_hook_ini (size_t alignment, size_t sz,
1840	const void *caller) __THROW;
1841
1842	#if HAVE_MALLOC_INIT_HOOK
1843	void weak_variable (__malloc_initialize_hook) (void*) = NULL;
1844	compat_symbol (libc, __malloc_initialize_hook,
1845	__malloc_initialize_hook, GLIBC_2_0);
1846	#endif
1847
1848	void weak_variable (__free_hook) (void* *__ptr,
1849	const void *) = NULL;
1850	void weak_variable (__malloc_hook)
1851	(size_t __size, const void *) = malloc_hook_ini;
1852	void weak_variable (__realloc_hook)
1853	(void __ptr, size_t __size, const* void *)
1854	= realloc_hook_ini;
1855	void weak_variable (__memalign_hook)
1856	(size_t __alignment, size_t __size, const void *)
1857	= memalign_hook_ini;
1858	void weak_variable (__after_morecore_hook) (void*) = NULL;
1859
1860	/ This function is called from the arena shutdown hook, to free the*
1861	thread cache (if it exists). /*
1862	static void tcache_thread_shutdown (void);
1863
1864	/ ------------------ Testing support ----------------------------------/
1865
1866	static int perturb_byte;
1867
1868	static void
1869	alloc_perturb (char *p, size_t n)
1870	{
1871	if (__glibc_unlikely (perturb_byte))
1872	memset (p, perturb_byte ^ `0xff`, n);
1873	}
1874
1875	static void
1876	free_perturb (char *p, size_t n)
1877	{
1878	if (__glibc_unlikely (perturb_byte))
1879	memset (p, perturb_byte, n);
1880	}
1881
1882
1883
1884	#include <stap-probe.h>
1885
1886	/ ------------------- Support for multiple arenas -------------------- /
1887	#include "arena.c"
1888
1889	/*
1890	Debugging support
1891
1892	These routines make a number of assertions about the states
1893	of data structures that should be true at all times. If any
1894	are not true, it's very likely that a user program has somehow
1895	trashed memory. (It's also possible that there is a coding error
1896	in malloc. In which case, please report it!)
1897	*/
1898
1899	#if !MALLOC_DEBUG
1900
1901	# define check_chunk(A, P)
1902	# define check_free_chunk(A, P)
1903	# define check_inuse_chunk(A, P)
1904	# define check_remalloced_chunk(A, P, N)
1905	# define check_malloced_chunk(A, P, N)
1906	# define check_malloc_state(A)
1907
1908	#else
1909
1910	# define check_chunk(A, P) do_check_chunk (A, P)
1911	# define check_free_chunk(A, P) do_check_free_chunk (A, P)
1912	# define check_inuse_chunk(A, P) do_check_inuse_chunk (A, P)
1913	# define check_remalloced_chunk(A, P, N) do_check_remalloced_chunk (A, P, N)
1914	# define check_malloced_chunk(A, P, N) do_check_malloced_chunk (A, P, N)
1915	# define check_malloc_state(A) do_check_malloc_state (A)
1916
1917	/*
1918	Properties of all chunks
1919	*/
1920
1921	static void
1922	do_check_chunk (mstate av, mchunkptr p)
1923	{
1924	unsigned long sz = chunksize (p);
1925	/ min and max possible addresses assuming contiguous allocation /
1926	char max_address = (char* *) (av->top) + chunksize (av->top);
1927	char *min_address = max_address - av->system_mem;
1928
1929	if (!chunk_is_mmapped (p))
1930	{
1931	/ Has legal address ... /
1932	if (p != av->top)
1933	{
1934	if (contiguous (av))
1935	{
1936	assert (((char *) p) >= min_address);
1937	assert (((char ) p + sz) <= ((char* *) (av->top)));
1938	}
1939	}
1940	else
1941	{
1942	/ top size is always at least MINSIZE /
1943	assert ((unsigned long) (sz) >= MINSIZE);
1944	/ top predecessor always marked inuse /
1945	assert (prev_inuse (p));
1946	}
1947	}
1948	else if (!DUMPED_MAIN_ARENA_CHUNK (p))
1949	{
1950	/ address is outside main heap /
1951	if (contiguous (av) && av->top != initial_top (av))
1952	{
1953	assert (((char ) p) < min_address \|\| ((char* *) p) >= max_address);
1954	}
1955	/ chunk is page-aligned /
1956	assert (((prev_size (p) + sz) & (GLRO (dl_pagesize) - `1`)) == `0`);
1957	/ mem is aligned /
1958	assert (aligned_OK (chunk2mem (p)));
1959	}
1960	}
1961
1962	/*
1963	Properties of free chunks
1964	*/
1965
1966	static void
1967	do_check_free_chunk (mstate av, mchunkptr p)
1968	{
1969	INTERNAL_SIZE_T sz = chunksize_nomask (p) & ~(PREV_INUSE \| NON_MAIN_ARENA);
1970	mchunkptr next = chunk_at_offset (p, sz);
1971
1972	do_check_chunk (av, p);
1973
1974	/ Chunk must claim to be free ... /
1975	assert (!inuse (p));
1976	assert (!chunk_is_mmapped (p));
1977
1978	/ Unless a special marker, must have OK fields /
1979	if ((unsigned long) (sz) >= MINSIZE)
1980	{
1981	assert ((sz & MALLOC_ALIGN_MASK) == `0`);
1982	assert (aligned_OK (chunk2mem (p)));
1983	/ ... matching footer field /
1984	assert (prev_size (next_chunk (p)) == sz);
1985	/ ... and is fully consolidated /
1986	assert (prev_inuse (p));
1987	assert (next == av->top \|\| inuse (next));
1988
1989	/ ... and has minimally sane links /
1990	assert (p->fd->bk == p);
1991	assert (p->bk->fd == p);
1992	}
1993	else / markers are always of size SIZE_SZ /
1994	assert (sz == SIZE_SZ);
1995	}
1996
1997	/*
1998	Properties of inuse chunks
1999	*/
2000
2001	static void
2002	do_check_inuse_chunk (mstate av, mchunkptr p)
2003	{
2004	mchunkptr next;
2005
2006	do_check_chunk (av, p);
2007
2008	if (chunk_is_mmapped (p))
2009	return; / mmapped chunks have no next/prev /
2010
2011	/ Check whether it claims to be in use ... /
2012	assert (inuse (p));
2013
2014	next = next_chunk (p);
2015
2016	/ ... and is surrounded by OK chunks.*
2017	Since more things can be checked with free chunks than inuse ones,
2018	if an inuse chunk borders them and debug is on, it's worth doing them.
2019	*/
2020	if (!prev_inuse (p))
2021	{
2022	/ Note that we cannot even look at prev unless it is not inuse /
2023	mchunkptr prv = prev_chunk (p);
2024	assert (next_chunk (prv) == p);
2025	do_check_free_chunk (av, prv);
2026	}
2027
2028	if (next == av->top)
2029	{
2030	assert (prev_inuse (next));
2031	assert (chunksize (next) >= MINSIZE);
2032	}
2033	else if (!inuse (next))
2034	do_check_free_chunk (av, next);
2035	}
2036
2037	/*
2038	Properties of chunks recycled from fastbins
2039	*/
2040
2041	static void
2042	do_check_remalloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s)
2043	{
2044	INTERNAL_SIZE_T sz = chunksize_nomask (p) & ~(PREV_INUSE \| NON_MAIN_ARENA);
2045
2046	if (!chunk_is_mmapped (p))
2047	{
2048	assert (av == arena_for_chunk (p));
2049	if (chunk_main_arena (p))
2050	assert (av == &main_arena);
2051	else
2052	assert (av != &main_arena);
2053	}
2054
2055	do_check_inuse_chunk (av, p);
2056
2057	/ Legal size ... /
2058	assert ((sz & MALLOC_ALIGN_MASK) == `0`);
2059	assert ((unsigned long) (sz) >= MINSIZE);
2060	/ ... and alignment /
2061	assert (aligned_OK (chunk2mem (p)));
2062	/ chunk is less than MINSIZE more than request /
2063	assert ((long) (sz) - (long) (s) >= `0`);
2064	assert ((long) (sz) - (long) (s + MINSIZE) < `0`);
2065	}
2066
2067	/*
2068	Properties of nonrecycled chunks at the point they are malloced
2069	*/
2070
2071	static void
2072	do_check_malloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s)
2073	{
2074	/ same as recycled case ... /
2075	do_check_remalloced_chunk (av, p, s);
2076
2077	/*
2078	... plus, must obey implementation invariant that prev_inuse is
2079	always true of any allocated chunk; i.e., that each allocated
2080	chunk borders either a previously allocated and still in-use
2081	chunk, or the base of its memory arena. This is ensured
2082	by making all allocations from the `lowest' part of any found
2083	chunk. This does not necessarily hold however for chunks
2084	recycled via fastbins.
2085	*/
2086
2087	assert (prev_inuse (p));
2088	}
2089
2090
2091	/*
2092	Properties of malloc_state.
2093
2094	This may be useful for debugging malloc, as well as detecting user
2095	programmer errors that somehow write into malloc_state.
2096
2097	If you are extending or experimenting with this malloc, you can
2098	probably figure out how to hack this routine to print out or
2099	display chunk addresses, sizes, bins, and other instrumentation.
2100	*/
2101
2102	static void
2103	do_check_malloc_state (mstate av)
2104	{
2105	int i;
2106	mchunkptr p;
2107	mchunkptr q;
2108	mbinptr b;
2109	unsigned int idx;
2110	INTERNAL_SIZE_T size;
2111	unsigned long total = `0`;
2112	int max_fast_bin;
2113
2114	/ internal size_t must be no wider than pointer type /
2115	assert (sizeof (INTERNAL_SIZE_T) <= sizeof (char *));
2116
2117	/ alignment is a power of 2 /
2118	assert ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT - `1`)) == `0`);
2119
2120	/ Check the arena is initialized. /
2121	assert (av->top != `0`);
2122
2123	/ No memory has been allocated yet, so doing more tests is not possible. /
2124	if (av->top == initial_top (av))
2125	return;
2126
2127	/ pagesize is a power of 2 /
2128	assert (powerof2(GLRO (dl_pagesize)));
2129
2130	/ A contiguous main_arena is consistent with sbrk_base. /
2131	if (av == &main_arena && contiguous (av))
2132	assert ((char *) mp_.sbrk_base + av->system_mem ==
2133	(char *) av->top + chunksize (av->top));
2134
2135	/ properties of fastbins /
2136
2137	/ max_fast is in allowed range /
2138	assert ((get_max_fast () & ~`1`) <= request2size (MAX_FAST_SIZE));
2139
2140	max_fast_bin = fastbin_index (get_max_fast ());
2141
2142	for (i = `0`; i < NFASTBINS; ++i)
2143	{
2144	p = fastbin (av, i);
2145
2146	/ The following test can only be performed for the main arena.*
2147	While mallopt calls malloc_consolidate to get rid of all fast
2148	bins (especially those larger than the new maximum) this does
2149	only happen for the main arena. Trying to do this for any
2150	other arena would mean those arenas have to be locked and
2151	malloc_consolidate be called for them. This is excessive. And
2152	even if this is acceptable to somebody it still cannot solve
2153	the problem completely since if the arena is locked a
2154	concurrent malloc call might create a new arena which then
2155	could use the newly invalid fast bins. /*
2156
2157	/ all bins past max_fast are empty /
2158	if (av == &main_arena && i > max_fast_bin)
2159	assert (p == `0`);
2160
2161	while (p != `0`)
2162	{
2163	/ each chunk claims to be inuse /
2164	do_check_inuse_chunk (av, p);
2165	total += chunksize (p);
2166	/ chunk belongs in this bin /
2167	assert (fastbin_index (chunksize (p)) == i);
2168	p = p->fd;
2169	}
2170	}
2171
2172	/ check normal bins /
2173	for (i = `1`; i < NBINS; ++i)
2174	{
2175	b = bin_at (av, i);
2176
2177	/ binmap is accurate (except for bin 1 == unsorted_chunks) /
2178	if (i >= `2`)
2179	{
2180	unsigned int binbit = get_binmap (av, i);
2181	int empty = last (b) == b;
2182	if (!binbit)
2183	assert (empty);
2184	else if (!empty)
2185	assert (binbit);
2186	}
2187
2188	for (p = last (b); p != b; p = p->bk)
2189	{
2190	/ each chunk claims to be free /
2191	do_check_free_chunk (av, p);
2192	size = chunksize (p);
2193	total += size;
2194	if (i >= `2`)
2195	{
2196	/ chunk belongs in bin /
2197	idx = bin_index (size);
2198	assert (idx == i);
2199	/ lists are sorted /
2200	assert (p->bk == b \|\|
2201	(unsigned long) chunksize (p->bk) >= (unsigned long) chunksize (p));
2202
2203	if (!in_smallbin_range (size))
2204	{
2205	if (p->fd_nextsize != NULL)
2206	{
2207	if (p->fd_nextsize == p)
2208	assert (p->bk_nextsize == p);
2209	else
2210	{
2211	if (p->fd_nextsize == first (b))
2212	assert (chunksize (p) < chunksize (p->fd_nextsize));
2213	else
2214	assert (chunksize (p) > chunksize (p->fd_nextsize));
2215
2216	if (p == first (b))
2217	assert (chunksize (p) > chunksize (p->bk_nextsize));
2218	else
2219	assert (chunksize (p) < chunksize (p->bk_nextsize));
2220	}
2221	}
2222	else
2223	assert (p->bk_nextsize == NULL);
2224	}
2225	}
2226	else if (!in_smallbin_range (size))
2227	assert (p->fd_nextsize == NULL && p->bk_nextsize == NULL);
2228	/ chunk is followed by a legal chain of inuse chunks /
2229	for (q = next_chunk (p);
2230	(q != av->top && inuse (q) &&
2231	(unsigned long) (chunksize (q)) >= MINSIZE);
2232	q = next_chunk (q))
2233	do_check_inuse_chunk (av, q);
2234	}
2235	}
2236
2237	/ top chunk is OK /
2238	check_chunk (av, av->top);
2239	}
2240	#endif
2241
2242
2243	/ ----------------- Support for debugging hooks -------------------- /
2244	#include "hooks.c"
2245
2246
2247	/ ----------- Routines dealing with system allocation -------------- /
2248
2249	/*
2250	sysmalloc handles malloc cases requiring more memory from the system.
2251	On entry, it is assumed that av->top does not have enough
2252	space to service request for nb bytes, thus requiring that av->top
2253	be extended or replaced.
2254	*/
2255
2256	static void *
2257	sysmalloc (INTERNAL_SIZE_T nb, mstate av)
2258	{
2259	mchunkptr old_top; / incoming value of av->top /
2260	INTERNAL_SIZE_T old_size; / its size /
2261	char old_end; /* its end address /
2262
2263	long size; / arg to first MORECORE or mmap call /
2264	char brk; /* return value from MORECORE /
2265
2266	long correction; / arg to 2nd MORECORE call /
2267	char snd_brk; /* 2nd return val /
2268
2269	INTERNAL_SIZE_T front_misalign; / unusable bytes at front of new space /
2270	INTERNAL_SIZE_T end_misalign; / partial page left at end of new space /
2271	char aligned_brk; /* aligned offset into brk /
2272
2273	mchunkptr p; / the allocated/returned chunk /
2274	mchunkptr remainder; / remainder from allocation /
2275	unsigned long remainder_size; / its size /
2276
2277
2278	size_t pagesize = GLRO (dl_pagesize);
2279	bool tried_mmap = false;
2280
2281
2282	/*
2283	If have mmap, and the request size meets the mmap threshold, and
2284	the system supports mmap, and there are few enough currently
2285	allocated mmapped regions, try to directly map this request
2286	rather than expanding top.
2287	*/
2288
2289	if (av == NULL
2290	\|\| ((unsigned long) (nb) >= (unsigned long) (mp_.mmap_threshold)
2291	&& (mp_.n_mmaps < mp_.n_mmaps_max)))
2292	{
2293	char mm; /* return value from mmap call/
2294
2295	try_mmap:
2296	/*
2297	Round up size to nearest page. For mmapped chunks, the overhead
2298	is one SIZE_SZ unit larger than for normal chunks, because there
2299	is no following chunk whose prev_size field could be used.
2300
2301	See the front_misalign handling below, for glibc there is no
2302	need for further alignments unless we have have high alignment.
2303	*/
2304	if (MALLOC_ALIGNMENT == `2` * SIZE_SZ)
2305	size = ALIGN_UP (nb + SIZE_SZ, pagesize);
2306	else
2307	size = ALIGN_UP (nb + SIZE_SZ + MALLOC_ALIGN_MASK, pagesize);
2308	tried_mmap = true;
2309
2310	/ Don't try if size wraps around 0 /
2311	if ((unsigned long) (size) > (unsigned long) (nb))
2312	{
2313	mm = (char *) (MMAP (`0`, size, PROT_READ \| PROT_WRITE, `0`));
2314
2315	if (mm != MAP_FAILED)
2316	{
2317	/*
2318	The offset to the start of the mmapped region is stored
2319	in the prev_size field of the chunk. This allows us to adjust
2320	returned start address to meet alignment requirements here
2321	and in memalign(), and still be able to compute proper
2322	address argument for later munmap in free() and realloc().
2323	*/
2324
2325	if (MALLOC_ALIGNMENT == `2` * SIZE_SZ)
2326	{
2327	/ For glibc, chunk2mem increases the address by 2SIZE_SZ and
2328	MALLOC_ALIGN_MASK is 2SIZE_SZ-1. Each mmap'ed area is page*
2329	aligned and therefore definitely MALLOC_ALIGN_MASK-aligned. /*
2330	assert (((INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK) == `0`);
2331	front_misalign = `0`;
2332	}
2333	else
2334	front_misalign = (INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK;
2335	if (front_misalign > `0`)
2336	{
2337	correction = MALLOC_ALIGNMENT - front_misalign;
2338	p = (mchunkptr) (mm + correction);
2339	set_prev_size (p, correction);
2340	set_head (p, (size - correction) \| IS_MMAPPED);
2341	}
2342	else
2343	{
2344	p = (mchunkptr) mm;
2345	set_prev_size (p, `0`);
2346	set_head (p, size \| IS_MMAPPED);
2347	}
2348
2349	/ update statistics /
2350
2351	int new = atomic_exchange_and_add (&mp_.n_mmaps, `1`) + `1`;
2352	atomic_max (&mp_.max_n_mmaps, new);
2353
2354	unsigned long sum;
2355	sum = atomic_exchange_and_add (&mp_.mmapped_mem, size) + size;
2356	atomic_max (&mp_.max_mmapped_mem, sum);
2357
2358	check_chunk (av, p);
2359
2360	return chunk2mem (p);
2361	}
2362	}
2363	}
2364
2365	/ There are no usable arenas and mmap also failed. /
2366	if (av == NULL)
2367	return `0`;
2368
2369	/ Record incoming configuration of top /
2370
2371	old_top = av->top;
2372	old_size = chunksize (old_top);
2373	old_end = (char *) (chunk_at_offset (old_top, old_size));
2374
2375	brk = snd_brk = (char *) (MORECORE_FAILURE);
2376
2377	/*
2378	If not the first time through, we require old_size to be
2379	at least MINSIZE and to have prev_inuse set.
2380	*/
2381
2382	assert ((old_top == initial_top (av) && old_size == `0`) \|\|
2383	((unsigned long) (old_size) >= MINSIZE &&
2384	prev_inuse (old_top) &&
2385	((unsigned long) old_end & (pagesize - `1`)) == `0`));
2386
2387	/ Precondition: not enough current space to satisfy nb request /
2388	assert ((unsigned long) (old_size) < (unsigned long) (nb + MINSIZE));
2389
2390
2391	if (av != &main_arena)
2392	{
2393	heap_info old_heap, heap;
2394	size_t old_heap_size;
2395
2396	/ First try to extend the current heap. /
2397	old_heap = heap_for_ptr (old_top);
2398	old_heap_size = old_heap->size;
2399	if ((long) (MINSIZE + nb - old_size) > `0`
2400	&& grow_heap (old_heap, MINSIZE + nb - old_size) == `0`)
2401	{
2402	av->system_mem += old_heap->size - old_heap_size;
2403	set_head (old_top, (((char ) old_heap + old_heap->size) - (char* *) old_top)
2404	\| PREV_INUSE);
2405	}
2406	else if ((heap = new_heap (nb + (MINSIZE + sizeof (*heap)), mp_.top_pad)))
2407	{
2408	/ Use a newly allocated heap. /
2409	heap->ar_ptr = av;
2410	heap->prev = old_heap;
2411	av->system_mem += heap->size;
2412	/ Set up the new top. /
2413	top (av) = chunk_at_offset (heap, sizeof (*heap));
2414	set_head (top (av), (heap->size - sizeof (*heap)) \| PREV_INUSE);
2415
2416	/ Setup fencepost and free the old top chunk with a multiple of*
2417	MALLOC_ALIGNMENT in size. /*
2418	/ The fencepost takes at least MINSIZE bytes, because it might*
2419	become the top chunk again later. Note that a footer is set
2420	up, too, although the chunk is marked in use. /*
2421	old_size = (old_size - MINSIZE) & ~MALLOC_ALIGN_MASK;
2422	set_head (chunk_at_offset (old_top, old_size + `2` * SIZE_SZ), `0` \| PREV_INUSE);
2423	if (old_size >= MINSIZE)
2424	{
2425	set_head (chunk_at_offset (old_top, old_size), (`2` * SIZE_SZ) \| PREV_INUSE);
2426	set_foot (chunk_at_offset (old_top, old_size), (`2` * SIZE_SZ));
2427	set_head (old_top, old_size \| PREV_INUSE \| NON_MAIN_ARENA);
2428	_int_free (av, old_top, `1`);
2429	}
2430	else
2431	{
2432	set_head (old_top, (old_size + `2` * SIZE_SZ) \| PREV_INUSE);
2433	set_foot (old_top, (old_size + `2` * SIZE_SZ));
2434	}
2435	}
2436	else if (!tried_mmap)
2437	/ We can at least try to use to mmap memory. /
2438	goto try_mmap;
2439	}
2440	else / av == main_arena /
2441
2442
2443	{ / Request enough space for nb + pad + overhead /
2444	size = nb + mp_.top_pad + MINSIZE;
2445
2446	/*
2447	If contiguous, we can subtract out existing space that we hope to
2448	combine with new space. We add it back later only if
2449	we don't actually get contiguous space.
2450	*/
2451
2452	if (contiguous (av))
2453	size -= old_size;
2454
2455	/*
2456	Round to a multiple of page size.
2457	If MORECORE is not contiguous, this ensures that we only call it
2458	with whole-page arguments. And if MORECORE is contiguous and
2459	this is not first time through, this preserves page-alignment of
2460	previous calls. Otherwise, we correct to page-align below.
2461	*/
2462
2463	size = ALIGN_UP (size, pagesize);
2464
2465	/*
2466	Don't try to call MORECORE if argument is so big as to appear
2467	negative. Note that since mmap takes size_t arg, it may succeed
2468	below even if we cannot call MORECORE.
2469	*/
2470
2471	if (size > `0`)
2472	{
2473	brk = (char *) (MORECORE (size));
2474	LIBC_PROBE (memory_sbrk_more, `2`, brk, size);
2475	}
2476
2477	if (brk != (char *) (MORECORE_FAILURE))
2478	{
2479	/ Call the `morecore' hook if necessary. /
2480	void (hook) (void*) = atomic_forced_read (__after_morecore_hook);
2481	if (__builtin_expect (hook != NULL, `0`))
2482	(*hook)();
2483	}
2484	else
2485	{
2486	/*
2487	If have mmap, try using it as a backup when MORECORE fails or
2488	cannot be used. This is worth doing on systems that have "holes" in
2489	address space, so sbrk cannot extend to give contiguous space, but
2490	space is available elsewhere. Note that we ignore mmap max count
2491	and threshold limits, since the space will not be used as a
2492	segregated mmap region.
2493	*/
2494
2495	/ Cannot merge with old top, so add its size back in /
2496	if (contiguous (av))
2497	size = ALIGN_UP (size + old_size, pagesize);
2498
2499	/ If we are relying on mmap as backup, then use larger units /
2500	if ((unsigned long) (size) < (unsigned long) (MMAP_AS_MORECORE_SIZE))
2501	size = MMAP_AS_MORECORE_SIZE;
2502
2503	/ Don't try if size wraps around 0 /
2504	if ((unsigned long) (size) > (unsigned long) (nb))
2505	{
2506	char mbrk = (char* *) (MMAP (`0`, size, PROT_READ \| PROT_WRITE, `0`));
2507
2508	if (mbrk != MAP_FAILED)
2509	{
2510	/ We do not need, and cannot use, another sbrk call to find end /
2511	brk = mbrk;
2512	snd_brk = brk + size;
2513
2514	/*
2515	Record that we no longer have a contiguous sbrk region.
2516	After the first time mmap is used as backup, we do not
2517	ever rely on contiguous space since this could incorrectly
2518	bridge regions.
2519	*/
2520	set_noncontiguous (av);
2521	}
2522	}
2523	}
2524
2525	if (brk != (char *) (MORECORE_FAILURE))
2526	{
2527	if (mp_.sbrk_base == `0`)
2528	mp_.sbrk_base = brk;
2529	av->system_mem += size;
2530
2531	/*
2532	If MORECORE extends previous space, we can likewise extend top size.
2533	*/
2534
2535	if (brk == old_end && snd_brk == (char *) (MORECORE_FAILURE))
2536	set_head (old_top, (size + old_size) \| PREV_INUSE);
2537
2538	else if (contiguous (av) && old_size && brk < old_end)
2539	/ Oops! Someone else killed our space.. Can't touch anything. /
2540	malloc_printerr ("break adjusted to free malloc space");
2541
2542	/*
2543	Otherwise, make adjustments:
2544
2545	* If the first time through or noncontiguous, we need to call sbrk
2546	just to find out where the end of memory lies.
2547
2548	* We need to ensure that all returned chunks from malloc will meet
2549	MALLOC_ALIGNMENT
2550
2551	* If there was an intervening foreign sbrk, we need to adjust sbrk
2552	request size to account for fact that we will not be able to
2553	combine new space with existing space in old_top.
2554
2555	* Almost all systems internally allocate whole pages at a time, in
2556	which case we might as well use the whole last page of request.
2557	So we allocate enough more memory to hit a page boundary now,
2558	which in turn causes future contiguous calls to page-align.
2559	*/
2560
2561	else
2562	{
2563	front_misalign = `0`;
2564	end_misalign = `0`;
2565	correction = `0`;
2566	aligned_brk = brk;
2567
2568	/ handle contiguous cases /
2569	if (contiguous (av))
2570	{
2571	/ Count foreign sbrk as system_mem. /
2572	if (old_size)
2573	av->system_mem += brk - old_end;
2574
2575	/ Guarantee alignment of first new chunk made from this space /
2576
2577	front_misalign = (INTERNAL_SIZE_T) chunk2mem (brk) & MALLOC_ALIGN_MASK;
2578	if (front_misalign > `0`)
2579	{
2580	/*
2581	Skip over some bytes to arrive at an aligned position.
2582	We don't need to specially mark these wasted front bytes.
2583	They will never be accessed anyway because
2584	prev_inuse of av->top (and any chunk created from its start)
2585	is always true after initialization.
2586	*/
2587
2588	correction = MALLOC_ALIGNMENT - front_misalign;
2589	aligned_brk += correction;
2590	}
2591
2592	/*
2593	If this isn't adjacent to existing space, then we will not
2594	be able to merge with old_top space, so must add to 2nd request.
2595	*/
2596
2597	correction += old_size;
2598
2599	/ Extend the end address to hit a page boundary /
2600	end_misalign = (INTERNAL_SIZE_T) (brk + size + correction);
2601	correction += (ALIGN_UP (end_misalign, pagesize)) - end_misalign;
2602
2603	assert (correction >= `0`);
2604	snd_brk = (char *) (MORECORE (correction));
2605
2606	/*
2607	If can't allocate correction, try to at least find out current
2608	brk. It might be enough to proceed without failing.
2609
2610	Note that if second sbrk did NOT fail, we assume that space
2611	is contiguous with first sbrk. This is a safe assumption unless
2612	program is multithreaded but doesn't use locks and a foreign sbrk
2613	occurred between our first and second calls.
2614	*/
2615
2616	if (snd_brk == (char *) (MORECORE_FAILURE))
2617	{
2618	correction = `0`;
2619	snd_brk = (char *) (MORECORE (`0`));
2620	}
2621	else
2622	{
2623	/ Call the `morecore' hook if necessary. /
2624	void (hook) (void*) = atomic_forced_read (__after_morecore_hook);
2625	if (__builtin_expect (hook != NULL, `0`))
2626	(*hook)();
2627	}
2628	}
2629
2630	/ handle non-contiguous cases /
2631	else
2632	{
2633	if (MALLOC_ALIGNMENT == `2` * SIZE_SZ)
2634	/ MORECORE/mmap must correctly align /
2635	assert (((unsigned long) chunk2mem (brk) & MALLOC_ALIGN_MASK) == `0`);
2636	else
2637	{
2638	front_misalign = (INTERNAL_SIZE_T) chunk2mem (brk) & MALLOC_ALIGN_MASK;
2639	if (front_misalign > `0`)
2640	{
2641	/*
2642	Skip over some bytes to arrive at an aligned position.
2643	We don't need to specially mark these wasted front bytes.
2644	They will never be accessed anyway because
2645	prev_inuse of av->top (and any chunk created from its start)
2646	is always true after initialization.
2647	*/
2648
2649	aligned_brk += MALLOC_ALIGNMENT - front_misalign;
2650	}
2651	}
2652
2653	/ Find out current end of memory /
2654	if (snd_brk == (char *) (MORECORE_FAILURE))
2655	{
2656	snd_brk = (char *) (MORECORE (`0`));
2657	}
2658	}
2659
2660	/ Adjust top based on results of second sbrk /
2661	if (snd_brk != (char *) (MORECORE_FAILURE))
2662	{
2663	av->top = (mchunkptr) aligned_brk;
2664	set_head (av->top, (snd_brk - aligned_brk + correction) \| PREV_INUSE);
2665	av->system_mem += correction;
2666
2667	/*
2668	If not the first time through, we either have a
2669	gap due to foreign sbrk or a non-contiguous region. Insert a
2670	double fencepost at old_top to prevent consolidation with space
2671	we don't own. These fenceposts are artificial chunks that are
2672	marked as inuse and are in any case too small to use. We need
2673	two to make sizes and alignments work out.
2674	*/
2675
2676	if (old_size != `0`)
2677	{
2678	/*
2679	Shrink old_top to insert fenceposts, keeping size a
2680	multiple of MALLOC_ALIGNMENT. We know there is at least
2681	enough space in old_top to do this.
2682	*/
2683	old_size = (old_size - `4` * SIZE_SZ) & ~MALLOC_ALIGN_MASK;
2684	set_head (old_top, old_size \| PREV_INUSE);
2685
2686	/*
2687	Note that the following assignments completely overwrite
2688	old_top when old_size was previously MINSIZE. This is
2689	intentional. We need the fencepost, even if old_top otherwise gets
2690	lost.
2691	*/
2692	set_head (chunk_at_offset (old_top, old_size),
2693	(`2` * SIZE_SZ) \| PREV_INUSE);
2694	set_head (chunk_at_offset (old_top, old_size + `2` * SIZE_SZ),
2695	(`2` * SIZE_SZ) \| PREV_INUSE);
2696
2697	/ If possible, release the rest. /
2698	if (old_size >= MINSIZE)
2699	{
2700	_int_free (av, old_top, `1`);
2701	}
2702	}
2703	}
2704	}
2705	}
2706	} / if (av != &main_arena) /
2707
2708	if ((unsigned long) av->system_mem > (unsigned long) (av->max_system_mem))
2709	av->max_system_mem = av->system_mem;
2710	check_malloc_state (av);
2711
2712	/ finally, do the allocation /
2713	p = av->top;
2714	size = chunksize (p);
2715
2716	/ check that one of the above allocation paths succeeded /
2717	if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
2718	{
2719	remainder_size = size - nb;
2720	remainder = chunk_at_offset (p, nb);
2721	av->top = remainder;
2722	set_head (p, nb \| PREV_INUSE \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
2723	set_head (remainder, remainder_size \| PREV_INUSE);
2724	check_malloced_chunk (av, p, nb);
2725	return chunk2mem (p);
2726	}
2727
2728	/ catch all failure paths /
2729	__set_errno (ENOMEM);
2730	return `0`;
2731	}
2732
2733
2734	/*
2735	systrim is an inverse of sorts to sysmalloc. It gives memory back
2736	to the system (via negative arguments to sbrk) if there is unused
2737	memory at the `high' end of the malloc pool. It is called
2738	automatically by free() when top space exceeds the trim
2739	threshold. It is also called by the public malloc_trim routine. It
2740	returns 1 if it actually released any memory, else 0.
2741	*/
2742
2743	static int
2744	systrim (size_t pad, mstate av)
2745	{
2746	long top_size; / Amount of top-most memory /
2747	long extra; / Amount to release /
2748	long released; / Amount actually released /
2749	char current_brk; /* address returned by pre-check sbrk call /
2750	char new_brk; /* address returned by post-check sbrk call /
2751	size_t pagesize;
2752	long top_area;
2753
2754	pagesize = GLRO (dl_pagesize);
2755	top_size = chunksize (av->top);
2756
2757	top_area = top_size - MINSIZE - `1`;
2758	if (top_area <= pad)
2759	return `0`;
2760
2761	/ Release in pagesize units and round down to the nearest page. /
2762	extra = ALIGN_DOWN(top_area - pad, pagesize);
2763
2764	if (extra == `0`)
2765	return `0`;
2766
2767	/*
2768	Only proceed if end of memory is where we last set it.
2769	This avoids problems if there were foreign sbrk calls.
2770	*/
2771	current_brk = (char *) (MORECORE (`0`));
2772	if (current_brk == (char *) (av->top) + top_size)
2773	{
2774	/*
2775	Attempt to release memory. We ignore MORECORE return value,
2776	and instead call again to find out where new end of memory is.
2777	This avoids problems if first call releases less than we asked,
2778	of if failure somehow altered brk value. (We could still
2779	encounter problems if it altered brk in some very bad way,
2780	but the only thing we can do is adjust anyway, which will cause
2781	some downstream failure.)
2782	*/
2783
2784	MORECORE (-extra);
2785	/ Call the `morecore' hook if necessary. /
2786	void (hook) (void*) = atomic_forced_read (__after_morecore_hook);
2787	if (__builtin_expect (hook != NULL, `0`))
2788	(*hook)();
2789	new_brk = (char *) (MORECORE (`0`));
2790
2791	LIBC_PROBE (memory_sbrk_less, `2`, new_brk, extra);
2792
2793	if (new_brk != (char *) MORECORE_FAILURE)
2794	{
2795	released = (long) (current_brk - new_brk);
2796
2797	if (released != `0`)
2798	{
2799	/ Success. Adjust top. /
2800	av->system_mem -= released;
2801	set_head (av->top, (top_size - released) \| PREV_INUSE);
2802	check_malloc_state (av);
2803	return `1`;
2804	}
2805	}
2806	}
2807	return `0`;
2808	}
2809
2810	static void
2811	munmap_chunk (mchunkptr p)
2812	{
2813	INTERNAL_SIZE_T size = chunksize (p);
2814
2815	assert (chunk_is_mmapped (p));
2816
2817	/ Do nothing if the chunk is a faked mmapped chunk in the dumped*
2818	main arena. We never free this memory. /*
2819	if (DUMPED_MAIN_ARENA_CHUNK (p))
2820	return;
2821
2822	uintptr_t block = (uintptr_t) p - prev_size (p);
2823	size_t total_size = prev_size (p) + size;
2824	/ Unfortunately we have to do the compilers job by hand here. Normally*
2825	we would test BLOCK and TOTAL-SIZE separately for compliance with the
2826	page size. But gcc does not recognize the optimization possibility
2827	(in the moment at least) so we combine the two values into one before
2828	the bit test. /*
2829	if (__builtin_expect (((block \| total_size) & (GLRO (dl_pagesize) - `1`)) != `0`, `0`))
2830	malloc_printerr ("munmap_chunk(): invalid pointer");
2831
2832	atomic_decrement (&mp_.n_mmaps);
2833	atomic_add (&mp_.mmapped_mem, -total_size);
2834
2835	/ If munmap failed the process virtual memory address space is in a*
2836	bad shape. Just leave the block hanging around, the process will
2837	terminate shortly anyway since not much can be done. /*
2838	__munmap ((char *) block, total_size);
2839	}
2840
2841	#if HAVE_MREMAP
2842
2843	static mchunkptr
2844	mremap_chunk (mchunkptr p, size_t new_size)
2845	{
2846	size_t pagesize = GLRO (dl_pagesize);
2847	INTERNAL_SIZE_T offset = prev_size (p);
2848	INTERNAL_SIZE_T size = chunksize (p);
2849	char *cp;
2850
2851	assert (chunk_is_mmapped (p));
2852	assert (((size + offset) & (GLRO (dl_pagesize) - `1`)) == `0`);
2853
2854	/ Note the extra SIZE_SZ overhead as in mmap_chunk(). /
2855	new_size = ALIGN_UP (new_size + offset + SIZE_SZ, pagesize);
2856
2857	/ No need to remap if the number of pages does not change. /
2858	if (size + offset == new_size)
2859	return p;
2860
2861	cp = (char ) __mremap ((char* *) p - offset, size + offset, new_size,
2862	MREMAP_MAYMOVE);
2863
2864	if (cp == MAP_FAILED)
2865	return `0`;
2866
2867	p = (mchunkptr) (cp + offset);
2868
2869	assert (aligned_OK (chunk2mem (p)));
2870
2871	assert (prev_size (p) == offset);
2872	set_head (p, (new_size - offset) \| IS_MMAPPED);
2873
2874	INTERNAL_SIZE_T new;
2875	new = atomic_exchange_and_add (&mp_.mmapped_mem, new_size - size - offset)
2876	+ new_size - size - offset;
2877	atomic_max (&mp_.max_mmapped_mem, new);
2878	return p;
2879	}
2880	#endif /* HAVE_MREMAP */
2881
2882	/------------------------ Public wrappers. --------------------------------/
2883
2884	#if USE_TCACHE
2885
2886	/ We overlay this structure on the user-data portion of a chunk when*
2887	the chunk is stored in the per-thread cache. /*
2888	typedef struct tcache_entry
2889	{
2890	struct tcache_entry *next;
2891	} tcache_entry;
2892
2893	/ There is one of these for each thread, which contains the*
2894	per-thread cache (hence "tcache_perthread_struct"). Keeping
2895	overall size low is mildly important. Note that COUNTS and ENTRIES
2896	are redundant (we could have just counted the linked list each
2897	time), this is for performance reasons. /*
2898	typedef struct tcache_perthread_struct
2899	{
2900	char counts[TCACHE_MAX_BINS];
2901	tcache_entry *entries[TCACHE_MAX_BINS];
2902	} tcache_perthread_struct;
2903
2904	static __thread bool tcache_shutting_down = false;
2905	static __thread tcache_perthread_struct *tcache = NULL;
2906
2907	/ Caller must ensure that we know tc_idx is valid and there's room*
2908	for more chunks. /*
2909	static __always_inline void
2910	tcache_put (mchunkptr chunk, size_t tc_idx)
2911	{
2912	tcache_entry e = (tcache_entry ) chunk2mem (chunk);
2913	assert (tc_idx < TCACHE_MAX_BINS);
2914	e->next = tcache->entries[tc_idx];
2915	tcache->entries[tc_idx] = e;
2916	++(tcache->counts[tc_idx]);
2917	}
2918
2919	/ Caller must ensure that we know tc_idx is valid and there's*
2920	available chunks to remove. /*
2921	static __always_inline void *
2922	tcache_get (size_t tc_idx)
2923	{
2924	tcache_entry *e = tcache->entries[tc_idx];
2925	assert (tc_idx < TCACHE_MAX_BINS);
2926	assert (tcache->entries[tc_idx] > `0`);
2927	tcache->entries[tc_idx] = e->next;
2928	--(tcache->counts[tc_idx]);
2929	return (void *) e;
2930	}
2931
2932	static void
2933	tcache_thread_shutdown (void)
2934	{
2935	int i;
2936	tcache_perthread_struct *tcache_tmp = tcache;
2937
2938	if (!tcache)
2939	return;
2940
2941	/ Disable the tcache and prevent it from being reinitialized. /
2942	tcache = NULL;
2943	tcache_shutting_down = true;
2944
2945	/ Free all of the entries and the tcache itself back to the arena*
2946	heap for coalescing. /*
2947	for (i = `0`; i < TCACHE_MAX_BINS; ++i)
2948	{
2949	while (tcache_tmp->entries[i])
2950	{
2951	tcache_entry *e = tcache_tmp->entries[i];
2952	tcache_tmp->entries[i] = e->next;
2953	__libc_free (e);
2954	}
2955	}
2956
2957	__libc_free (tcache_tmp);
2958	}
2959
2960	static void
2961	tcache_init(void)
2962	{
2963	mstate ar_ptr;
2964	void *victim = `0`;
2965	const size_t bytes = sizeof (tcache_perthread_struct);
2966
2967	if (tcache_shutting_down)
2968	return;
2969
2970	arena_get (ar_ptr, bytes);
2971	victim = _int_malloc (ar_ptr, bytes);
2972	if (!victim && ar_ptr != NULL)
2973	{
2974	ar_ptr = arena_get_retry (ar_ptr, bytes);
2975	victim = _int_malloc (ar_ptr, bytes);
2976	}
2977
2978
2979	if (ar_ptr != NULL)
2980	__libc_lock_unlock (ar_ptr->mutex);
2981
2982	/ In a low memory situation, we may not be able to allocate memory*
2983	- in which case, we just keep trying later. However, we
2984	typically do this very early, so either there is sufficient
2985	memory, or there isn't enough memory to do non-trivial
2986	allocations anyway. /*
2987	if (victim)
2988	{
2989	tcache = (tcache_perthread_struct *) victim;
2990	memset (tcache, `0`, sizeof (tcache_perthread_struct));
2991	}
2992
2993	}
2994
2995	# define MAYBE_INIT_TCACHE() \
2996	if (__glibc_unlikely (tcache == NULL)) \
2997	tcache_init();
2998
2999	#else /* !USE_TCACHE */
3000	# define MAYBE_INIT_TCACHE()
3001
3002	static void
3003	tcache_thread_shutdown (void)
3004	{
3005	/ Nothing to do if there is no thread cache. /
3006	}
3007
3008	#endif /* !USE_TCACHE */
3009
3010	void *
3011	__libc_malloc (size_t bytes)
3012	{
3013	mstate ar_ptr;
3014	void *victim;
3015
3016	void (hook) (size_t, const void *)
3017	= atomic_forced_read (__malloc_hook);
3018	if (__builtin_expect (hook != NULL, `0`))
3019	return (*hook)(bytes, RETURN_ADDRESS (`0`));
3020	#if USE_TCACHE
3021	/ int_free also calls request2size, be careful to not pad twice. /
3022	size_t tbytes;
3023	checked_request2size (bytes, tbytes);
3024	size_t tc_idx = csize2tidx (tbytes);
3025
3026	MAYBE_INIT_TCACHE ();
3027
3028	DIAG_PUSH_NEEDS_COMMENT;
3029	if (tc_idx < mp_.tcache_bins
3030	/&& tc_idx < TCACHE_MAX_BINS/ / to appease gcc /
3031	&& tcache
3032	&& tcache->entries[tc_idx] != NULL)
3033	{
3034	return tcache_get (tc_idx);
3035	}
3036	DIAG_POP_NEEDS_COMMENT;
3037	#endif
3038
3039	if (SINGLE_THREAD_P)
3040	{
3041	victim = _int_malloc (&main_arena, bytes);
3042	assert (!victim \|\| chunk_is_mmapped (mem2chunk (victim)) \|\|
3043	&main_arena == arena_for_chunk (mem2chunk (victim)));
3044	return victim;
3045	}
3046
3047	arena_get (ar_ptr, bytes);
3048
3049	victim = _int_malloc (ar_ptr, bytes);
3050	/ Retry with another arena only if we were able to find a usable arena*
3051	before. /*
3052	if (!victim && ar_ptr != NULL)
3053	{
3054	LIBC_PROBE (memory_malloc_retry, `1`, bytes);
3055	ar_ptr = arena_get_retry (ar_ptr, bytes);
3056	victim = _int_malloc (ar_ptr, bytes);
3057	}
3058
3059	if (ar_ptr != NULL)
3060	__libc_lock_unlock (ar_ptr->mutex);
3061
3062	assert (!victim \|\| chunk_is_mmapped (mem2chunk (victim)) \|\|
3063	ar_ptr == arena_for_chunk (mem2chunk (victim)));
3064	return victim;
3065	}
3066	libc_hidden_def (__libc_malloc)
3067
3068	void
3069	__libc_free (void *mem)
3070	{
3071	mstate ar_ptr;
3072	mchunkptr p; / chunk corresponding to mem /
3073
3074	void (hook) (void* , const* void *)
3075	= atomic_forced_read (__free_hook);
3076	if (__builtin_expect (hook != NULL, `0`))
3077	{
3078	(*hook)(mem, RETURN_ADDRESS (`0`));
3079	return;
3080	}
3081
3082	if (mem == `0`) / free(0) has no effect /
3083	return;
3084
3085	p = mem2chunk (mem);
3086
3087	if (chunk_is_mmapped (p)) / release mmapped memory. /
3088	{
3089	/ See if the dynamic brk/mmap threshold needs adjusting.*
3090	Dumped fake mmapped chunks do not affect the threshold. /*
3091	if (!mp_.no_dyn_threshold
3092	&& chunksize_nomask (p) > mp_.mmap_threshold
3093	&& chunksize_nomask (p) <= DEFAULT_MMAP_THRESHOLD_MAX
3094	&& !DUMPED_MAIN_ARENA_CHUNK (p))
3095	{
3096	mp_.mmap_threshold = chunksize (p);
3097	mp_.trim_threshold = `2` * mp_.mmap_threshold;
3098	LIBC_PROBE (memory_mallopt_free_dyn_thresholds, `2`,
3099	mp_.mmap_threshold, mp_.trim_threshold);
3100	}
3101	munmap_chunk (p);
3102	return;
3103	}
3104
3105	MAYBE_INIT_TCACHE ();
3106
3107	ar_ptr = arena_for_chunk (p);
3108	_int_free (ar_ptr, p, `0`);
3109	}
3110	libc_hidden_def (__libc_free)
3111
3112	void *
3113	__libc_realloc (void *oldmem, size_t bytes)
3114	{
3115	mstate ar_ptr;
3116	INTERNAL_SIZE_T nb; / padded request size /
3117
3118	void newp; /* chunk to return /
3119
3120	void (hook) (void , size_t, const* void *) =
3121	atomic_forced_read (__realloc_hook);
3122	if (__builtin_expect (hook != NULL, `0`))
3123	return (*hook)(oldmem, bytes, RETURN_ADDRESS (`0`));
3124
3125	#if REALLOC_ZERO_BYTES_FREES
3126	if (bytes == `0` && oldmem != NULL)
3127	{
3128	__libc_free (oldmem); return `0`;
3129	}
3130	#endif
3131
3132	/ realloc of null is supposed to be same as malloc /
3133	if (oldmem == `0`)
3134	return __libc_malloc (bytes);
3135
3136	/ chunk corresponding to oldmem /
3137	const mchunkptr oldp = mem2chunk (oldmem);
3138	/ its size /
3139	const INTERNAL_SIZE_T oldsize = chunksize (oldp);
3140
3141	if (chunk_is_mmapped (oldp))
3142	ar_ptr = NULL;
3143	else
3144	{
3145	MAYBE_INIT_TCACHE ();
3146	ar_ptr = arena_for_chunk (oldp);
3147	}
3148
3149	/ Little security check which won't hurt performance: the allocator*
3150	never wrapps around at the end of the address space. Therefore
3151	we can exclude some size values which might appear here by
3152	accident or by "design" from some intruder. We need to bypass
3153	this check for dumped fake mmap chunks from the old main arena
3154	because the new malloc may provide additional alignment. /*
3155	if ((__builtin_expect ((uintptr_t) oldp > (uintptr_t) -oldsize, `0`)
3156	\|\| __builtin_expect (misaligned_chunk (oldp), `0`))
3157	&& !DUMPED_MAIN_ARENA_CHUNK (oldp))
3158	malloc_printerr ("realloc(): invalid pointer");
3159
3160	checked_request2size (bytes, nb);
3161
3162	if (chunk_is_mmapped (oldp))
3163	{
3164	/ If this is a faked mmapped chunk from the dumped main arena,*
3165	always make a copy (and do not free the old chunk). /*
3166	if (DUMPED_MAIN_ARENA_CHUNK (oldp))
3167	{
3168	/ Must alloc, copy, free. /
3169	void *newmem = __libc_malloc (bytes);
3170	if (newmem == `0`)
3171	return NULL;
3172	/ Copy as many bytes as are available from the old chunk*
3173	and fit into the new size. NB: The overhead for faked
3174	mmapped chunks is only SIZE_SZ, not 2 SIZE_SZ as for*
3175	regular mmapped chunks. /*
3176	if (bytes > oldsize - SIZE_SZ)
3177	bytes = oldsize - SIZE_SZ;
3178	memcpy (newmem, oldmem, bytes);
3179	return newmem;
3180	}
3181
3182	void *newmem;
3183
3184	#if HAVE_MREMAP
3185	newp = mremap_chunk (oldp, nb);
3186	if (newp)
3187	return chunk2mem (newp);
3188	#endif
3189	/ Note the extra SIZE_SZ overhead. /
3190	if (oldsize - SIZE_SZ >= nb)
3191	return oldmem; / do nothing /
3192
3193	/ Must alloc, copy, free. /
3194	newmem = __libc_malloc (bytes);
3195	if (newmem == `0`)
3196	return `0`; / propagate failure /
3197
3198	memcpy (newmem, oldmem, oldsize - `2` * SIZE_SZ);
3199	munmap_chunk (oldp);
3200	return newmem;
3201	}
3202
3203	if (SINGLE_THREAD_P)
3204	{
3205	newp = _int_realloc (ar_ptr, oldp, oldsize, nb);
3206	assert (!newp \|\| chunk_is_mmapped (mem2chunk (newp)) \|\|
3207	ar_ptr == arena_for_chunk (mem2chunk (newp)));
3208
3209	return newp;
3210	}
3211
3212	__libc_lock_lock (ar_ptr->mutex);
3213
3214	newp = _int_realloc (ar_ptr, oldp, oldsize, nb);
3215
3216	__libc_lock_unlock (ar_ptr->mutex);
3217	assert (!newp \|\| chunk_is_mmapped (mem2chunk (newp)) \|\|
3218	ar_ptr == arena_for_chunk (mem2chunk (newp)));
3219
3220	if (newp == NULL)
3221	{
3222	/ Try harder to allocate memory in other arenas. /
3223	LIBC_PROBE (memory_realloc_retry, `2`, bytes, oldmem);
3224	newp = __libc_malloc (bytes);
3225	if (newp != NULL)
3226	{
3227	memcpy (newp, oldmem, oldsize - SIZE_SZ);
3228	_int_free (ar_ptr, oldp, `0`);
3229	}
3230	}
3231
3232	return newp;
3233	}
3234	libc_hidden_def (__libc_realloc)
3235
3236	void *
3237	__libc_memalign (size_t alignment, size_t bytes)
3238	{
3239	void *address = RETURN_ADDRESS (`0`);
3240	return _mid_memalign (alignment, bytes, address);
3241	}
3242
3243	static void *
3244	_mid_memalign (size_t alignment, size_t bytes, void *address)
3245	{
3246	mstate ar_ptr;
3247	void *p;
3248
3249	void (hook) (size_t, size_t, const void *) =
3250	atomic_forced_read (__memalign_hook);
3251	if (__builtin_expect (hook != NULL, `0`))
3252	return (*hook)(alignment, bytes, address);
3253
3254	/ If we need less alignment than we give anyway, just relay to malloc. /
3255	if (alignment <= MALLOC_ALIGNMENT)
3256	return __libc_malloc (bytes);
3257
3258	/ Otherwise, ensure that it is at least a minimum chunk size /
3259	if (alignment < MINSIZE)
3260	alignment = MINSIZE;
3261
3262	/ If the alignment is greater than SIZE_MAX / 2 + 1 it cannot be a*
3263	power of 2 and will cause overflow in the check below. /*
3264	if (alignment > SIZE_MAX / `2` + `1`)
3265	{
3266	__set_errno (EINVAL);
3267	return `0`;
3268	}
3269
3270	/ Check for overflow. /
3271	if (bytes > SIZE_MAX - alignment - MINSIZE)
3272	{
3273	__set_errno (ENOMEM);
3274	return `0`;
3275	}
3276
3277
3278	/ Make sure alignment is power of 2. /
3279	if (!powerof2 (alignment))
3280	{
3281	size_t a = MALLOC_ALIGNMENT * `2`;
3282	while (a < alignment)
3283	a <<= `1`;
3284	alignment = a;
3285	}
3286
3287	if (SINGLE_THREAD_P)
3288	{
3289	p = _int_memalign (&main_arena, alignment, bytes);
3290	assert (!p \|\| chunk_is_mmapped (mem2chunk (p)) \|\|
3291	&main_arena == arena_for_chunk (mem2chunk (p)));
3292
3293	return p;
3294	}
3295
3296	arena_get (ar_ptr, bytes + alignment + MINSIZE);
3297
3298	p = _int_memalign (ar_ptr, alignment, bytes);
3299	if (!p && ar_ptr != NULL)
3300	{
3301	LIBC_PROBE (memory_memalign_retry, `2`, bytes, alignment);
3302	ar_ptr = arena_get_retry (ar_ptr, bytes);
3303	p = _int_memalign (ar_ptr, alignment, bytes);
3304	}
3305
3306	if (ar_ptr != NULL)
3307	__libc_lock_unlock (ar_ptr->mutex);
3308
3309	assert (!p \|\| chunk_is_mmapped (mem2chunk (p)) \|\|
3310	ar_ptr == arena_for_chunk (mem2chunk (p)));
3311	return p;
3312	}
3313	/ For ISO C11. /
3314	weak_alias (__libc_memalign, aligned_alloc)
3315	libc_hidden_def (__libc_memalign)
3316
3317	void *
3318	__libc_valloc (size_t bytes)
3319	{
3320	if (__malloc_initialized < `0`)
3321	ptmalloc_init ();
3322
3323	void *address = RETURN_ADDRESS (`0`);
3324	size_t pagesize = GLRO (dl_pagesize);
3325	return _mid_memalign (pagesize, bytes, address);
3326	}
3327
3328	void *
3329	__libc_pvalloc (size_t bytes)
3330	{
3331	if (__malloc_initialized < `0`)
3332	ptmalloc_init ();
3333
3334	void *address = RETURN_ADDRESS (`0`);
3335	size_t pagesize = GLRO (dl_pagesize);
3336	size_t rounded_bytes = ALIGN_UP (bytes, pagesize);
3337
3338	/ Check for overflow. /
3339	if (bytes > SIZE_MAX - `2` * pagesize - MINSIZE)
3340	{
3341	__set_errno (ENOMEM);
3342	return `0`;
3343	}
3344
3345	return _mid_memalign (pagesize, rounded_bytes, address);
3346	}
3347
3348	void *
3349	__libc_calloc (size_t n, size_t elem_size)
3350	{
3351	mstate av;
3352	mchunkptr oldtop, p;
3353	INTERNAL_SIZE_T bytes, sz, csz, oldtopsize;
3354	void *mem;
3355	unsigned long clearsize;
3356	unsigned long nclears;
3357	INTERNAL_SIZE_T *d;
3358
3359	/ size_t is unsigned so the behavior on overflow is defined. /
3360	bytes = n * elem_size;
3361	#define HALF_INTERNAL_SIZE_T \
3362	(((INTERNAL_SIZE_T) 1) << (8 * sizeof (INTERNAL_SIZE_T) / 2))
3363	if (__builtin_expect ((n \| elem_size) >= HALF_INTERNAL_SIZE_T, `0`))
3364	{
3365	if (elem_size != `0` && bytes / elem_size != n)
3366	{
3367	__set_errno (ENOMEM);
3368	return `0`;
3369	}
3370	}
3371
3372	void (hook) (size_t, const void *) =
3373	atomic_forced_read (__malloc_hook);
3374	if (__builtin_expect (hook != NULL, `0`))
3375	{
3376	sz = bytes;
3377	mem = (*hook)(sz, RETURN_ADDRESS (`0`));
3378	if (mem == `0`)
3379	return `0`;
3380
3381	return memset (mem, `0`, sz);
3382	}
3383
3384	sz = bytes;
3385
3386	MAYBE_INIT_TCACHE ();
3387
3388	if (SINGLE_THREAD_P)
3389	av = &main_arena;
3390	else
3391	arena_get (av, sz);
3392
3393	if (av)
3394	{
3395	/ Check if we hand out the top chunk, in which case there may be no*
3396	need to clear. /*
3397	#if MORECORE_CLEARS
3398	oldtop = top (av);
3399	oldtopsize = chunksize (top (av));
3400	# if MORECORE_CLEARS < 2
3401	/ Only newly allocated memory is guaranteed to be cleared. /
3402	if (av == &main_arena &&
3403	oldtopsize < mp_.sbrk_base + av->max_system_mem - (char *) oldtop)
3404	oldtopsize = (mp_.sbrk_base + av->max_system_mem - (char *) oldtop);
3405	# endif
3406	if (av != &main_arena)
3407	{
3408	heap_info *heap = heap_for_ptr (oldtop);
3409	if (oldtopsize < (char ) heap + heap->mprotect_size - (char* *) oldtop)
3410	oldtopsize = (char ) heap + heap->mprotect_size - (char* *) oldtop;
3411	}
3412	#endif
3413	}
3414	else
3415	{
3416	/ No usable arenas. /
3417	oldtop = `0`;
3418	oldtopsize = `0`;
3419	}
3420	mem = _int_malloc (av, sz);
3421
3422	assert (!mem \|\| chunk_is_mmapped (mem2chunk (mem)) \|\|
3423	av == arena_for_chunk (mem2chunk (mem)));
3424
3425	if (!SINGLE_THREAD_P)
3426	{
3427	if (mem == `0` && av != NULL)
3428	{
3429	LIBC_PROBE (memory_calloc_retry, `1`, sz);
3430	av = arena_get_retry (av, sz);
3431	mem = _int_malloc (av, sz);
3432	}
3433
3434	if (av != NULL)
3435	__libc_lock_unlock (av->mutex);
3436	}
3437
3438	/ Allocation failed even after a retry. /
3439	if (mem == `0`)
3440	return `0`;
3441
3442	p = mem2chunk (mem);
3443
3444	/ Two optional cases in which clearing not necessary /
3445	if (chunk_is_mmapped (p))
3446	{
3447	if (__builtin_expect (perturb_byte, `0`))
3448	return memset (mem, `0`, sz);
3449
3450	return mem;
3451	}
3452
3453	csz = chunksize (p);
3454
3455	#if MORECORE_CLEARS
3456	if (perturb_byte == `0` && (p == oldtop && csz > oldtopsize))
3457	{
3458	/ clear only the bytes from non-freshly-sbrked memory /
3459	csz = oldtopsize;
3460	}
3461	#endif
3462
3463	/ Unroll clear of <= 36 bytes (72 if 8byte sizes). We know that*
3464	contents have an odd number of INTERNAL_SIZE_T-sized words;
3465	minimally 3. /*
3466	d = (INTERNAL_SIZE_T *) mem;
3467	clearsize = csz - SIZE_SZ;
3468	nclears = clearsize / sizeof (INTERNAL_SIZE_T);
3469	assert (nclears >= `3`);
3470
3471	if (nclears > `9`)
3472	return memset (d, `0`, clearsize);
3473
3474	else
3475	{
3476	*(d + `0`) = `0`;
3477	*(d + `1`) = `0`;
3478	*(d + `2`) = `0`;
3479	if (nclears > `4`)
3480	{
3481	*(d + `3`) = `0`;
3482	*(d + `4`) = `0`;
3483	if (nclears > `6`)
3484	{
3485	*(d + `5`) = `0`;
3486	*(d + `6`) = `0`;
3487	if (nclears > `8`)
3488	{
3489	*(d + `7`) = `0`;
3490	*(d + `8`) = `0`;
3491	}
3492	}
3493	}
3494	}
3495
3496	return mem;
3497	}
3498
3499	/*
3500	------------------------------ malloc ------------------------------
3501	*/
3502
3503	static void *
3504	_int_malloc (mstate av, size_t bytes)
3505	{
3506	INTERNAL_SIZE_T nb; / normalized request size /
3507	unsigned int idx; / associated bin index /
3508	mbinptr bin; / associated bin /
3509
3510	mchunkptr victim; / inspected/selected chunk /
3511	INTERNAL_SIZE_T size; / its size /
3512	int victim_index; / its bin index /
3513
3514	mchunkptr remainder; / remainder from a split /
3515	unsigned long remainder_size; / its size /
3516
3517	unsigned int block; / bit map traverser /
3518	unsigned int bit; / bit map traverser /
3519	unsigned int map; / current word of binmap /
3520
3521	mchunkptr fwd; / misc temp for linking /
3522	mchunkptr bck; / misc temp for linking /
3523
3524	#if USE_TCACHE
3525	size_t tcache_unsorted_count; / count of unsorted chunks processed /
3526	#endif
3527
3528	/*
3529	Convert request size to internal form by adding SIZE_SZ bytes
3530	overhead plus possibly more to obtain necessary alignment and/or
3531	to obtain a size of at least MINSIZE, the smallest allocatable
3532	size. Also, checked_request2size traps (returning 0) request sizes
3533	that are so large that they wrap around zero when padded and
3534	aligned.
3535	*/
3536
3537	checked_request2size (bytes, nb);
3538
3539	/ There are no usable arenas. Fall back to sysmalloc to get a chunk from*
3540	mmap. /*
3541	if (__glibc_unlikely (av == NULL))
3542	{
3543	void *p = sysmalloc (nb, av);
3544	if (p != NULL)
3545	alloc_perturb (p, bytes);
3546	return p;
3547	}
3548
3549	/*
3550	If the size qualifies as a fastbin, first check corresponding bin.
3551	This code is safe to execute even if av is not yet initialized, so we
3552	can try it without checking, which saves some time on this fast path.
3553	*/
3554
3555	#define REMOVE_FB(fb, victim, pp) \
3556	do \
3557	{ \
3558	victim = pp; \
3559	if (victim == NULL) \
3560	break; \
3561	} \
3562	while ((pp = catomic_compare_and_exchange_val_acq (fb, victim->fd, victim)) \
3563	!= victim); \
3564
3565	if ((unsigned long) (nb) <= (unsigned long) (get_max_fast ()))
3566	{
3567	idx = fastbin_index (nb);
3568	mfastbinptr *fb = &fastbin (av, idx);
3569	mchunkptr pp;
3570	victim = *fb;
3571
3572	if (victim != NULL)
3573	{
3574	if (SINGLE_THREAD_P)
3575	*fb = victim->fd;
3576	else
3577	REMOVE_FB (fb, pp, victim);
3578	if (__glibc_likely (victim != NULL))
3579	{
3580	size_t victim_idx = fastbin_index (chunksize (victim));
3581	if (__builtin_expect (victim_idx != idx, `0`))
3582	malloc_printerr ("malloc(): memory corruption (fast)");
3583	check_remalloced_chunk (av, victim, nb);
3584	#if USE_TCACHE
3585	/ While we're here, if we see other chunks of the same size,*
3586	stash them in the tcache. /*
3587	size_t tc_idx = csize2tidx (nb);
3588	if (tcache && tc_idx < mp_.tcache_bins)
3589	{
3590	mchunkptr tc_victim;
3591
3592	/ While bin not empty and tcache not full, copy chunks. /
3593	while (tcache->counts[tc_idx] < mp_.tcache_count
3594	&& (tc_victim = *fb) != NULL)
3595	{
3596	if (SINGLE_THREAD_P)
3597	*fb = tc_victim->fd;
3598	else
3599	{
3600	REMOVE_FB (fb, pp, tc_victim);
3601	if (__glibc_unlikely (tc_victim == NULL))
3602	break;
3603	}
3604	tcache_put (tc_victim, tc_idx);
3605	}
3606	}
3607	#endif
3608	void *p = chunk2mem (victim);
3609	alloc_perturb (p, bytes);
3610	return p;
3611	}
3612	}
3613	}
3614
3615	/*
3616	If a small request, check regular bin. Since these "smallbins"
3617	hold one size each, no searching within bins is necessary.
3618	(For a large request, we need to wait until unsorted chunks are
3619	processed to find best fit. But for small ones, fits are exact
3620	anyway, so we can check now, which is faster.)
3621	*/
3622
3623	if (in_smallbin_range (nb))
3624	{
3625	idx = smallbin_index (nb);
3626	bin = bin_at (av, idx);
3627
3628	if ((victim = last (bin)) != bin)
3629	{
3630	bck = victim->bk;
3631	if (__glibc_unlikely (bck->fd != victim))
3632	malloc_printerr ("malloc(): smallbin double linked list corrupted");
3633	set_inuse_bit_at_offset (victim, nb);
3634	bin->bk = bck;
3635	bck->fd = bin;
3636
3637	if (av != &main_arena)
3638	set_non_main_arena (victim);
3639	check_malloced_chunk (av, victim, nb);
3640	#if USE_TCACHE
3641	/ While we're here, if we see other chunks of the same size,*
3642	stash them in the tcache. /*
3643	size_t tc_idx = csize2tidx (nb);
3644	if (tcache && tc_idx < mp_.tcache_bins)
3645	{
3646	mchunkptr tc_victim;
3647
3648	/ While bin not empty and tcache not full, copy chunks over. /
3649	while (tcache->counts[tc_idx] < mp_.tcache_count
3650	&& (tc_victim = last (bin)) != bin)
3651	{
3652	if (tc_victim != `0`)
3653	{
3654	bck = tc_victim->bk;
3655	set_inuse_bit_at_offset (tc_victim, nb);
3656	if (av != &main_arena)
3657	set_non_main_arena (tc_victim);
3658	bin->bk = bck;
3659	bck->fd = bin;
3660
3661	tcache_put (tc_victim, tc_idx);
3662	}
3663	}
3664	}
3665	#endif
3666	void *p = chunk2mem (victim);
3667	alloc_perturb (p, bytes);
3668	return p;
3669	}
3670	}
3671
3672	/*
3673	If this is a large request, consolidate fastbins before continuing.
3674	While it might look excessive to kill all fastbins before
3675	even seeing if there is space available, this avoids
3676	fragmentation problems normally associated with fastbins.
3677	Also, in practice, programs tend to have runs of either small or
3678	large requests, but less often mixtures, so consolidation is not
3679	invoked all that often in most programs. And the programs that
3680	it is called frequently in otherwise tend to fragment.
3681	*/
3682
3683	else
3684	{
3685	idx = largebin_index (nb);
3686	if (atomic_load_relaxed (&av->have_fastchunks))
3687	malloc_consolidate (av);
3688	}
3689
3690	/*
3691	Process recently freed or remaindered chunks, taking one only if
3692	it is exact fit, or, if this a small request, the chunk is remainder from
3693	the most recent non-exact fit. Place other traversed chunks in
3694	bins. Note that this step is the only place in any routine where
3695	chunks are placed in bins.
3696
3697	The outer loop here is needed because we might not realize until
3698	near the end of malloc that we should have consolidated, so must
3699	do so and retry. This happens at most once, and only when we would
3700	otherwise need to expand memory to service a "small" request.
3701	*/
3702
3703	#if USE_TCACHE
3704	INTERNAL_SIZE_T tcache_nb = `0`;
3705	size_t tc_idx = csize2tidx (nb);
3706	if (tcache && tc_idx < mp_.tcache_bins)
3707	tcache_nb = nb;
3708	int return_cached = `0`;
3709
3710	tcache_unsorted_count = `0`;
3711	#endif
3712
3713	for (;; )
3714	{
3715	int iters = `0`;
3716	while ((victim = unsorted_chunks (av)->bk) != unsorted_chunks (av))
3717	{
3718	bck = victim->bk;
3719	if (__builtin_expect (chunksize_nomask (victim) <= `2` * SIZE_SZ, `0`)
3720	\|\| __builtin_expect (chunksize_nomask (victim)
3721	> av->system_mem, `0`))
3722	malloc_printerr ("malloc(): memory corruption");
3723	size = chunksize (victim);
3724
3725	/*
3726	If a small request, try to use last remainder if it is the
3727	only chunk in unsorted bin. This helps promote locality for
3728	runs of consecutive small requests. This is the only
3729	exception to best-fit, and applies only when there is
3730	no exact fit for a small chunk.
3731	*/
3732
3733	if (in_smallbin_range (nb) &&
3734	bck == unsorted_chunks (av) &&
3735	victim == av->last_remainder &&
3736	(unsigned long) (size) > (unsigned long) (nb + MINSIZE))
3737	{
3738	/ split and reattach remainder /
3739	remainder_size = size - nb;
3740	remainder = chunk_at_offset (victim, nb);
3741	unsorted_chunks (av)->bk = unsorted_chunks (av)->fd = remainder;
3742	av->last_remainder = remainder;
3743	remainder->bk = remainder->fd = unsorted_chunks (av);
3744	if (!in_smallbin_range (remainder_size))
3745	{
3746	remainder->fd_nextsize = NULL;
3747	remainder->bk_nextsize = NULL;
3748	}
3749
3750	set_head (victim, nb \| PREV_INUSE \|
3751	(av != &main_arena ? NON_MAIN_ARENA : `0`));
3752	set_head (remainder, remainder_size \| PREV_INUSE);
3753	set_foot (remainder, remainder_size);
3754
3755	check_malloced_chunk (av, victim, nb);
3756	void *p = chunk2mem (victim);
3757	alloc_perturb (p, bytes);
3758	return p;
3759	}
3760
3761	/ remove from unsorted list /
3762	if (__glibc_unlikely (bck->fd != victim))
3763	malloc_printerr ("malloc(): corrupted unsorted chunks 3");
3764	unsorted_chunks (av)->bk = bck;
3765	bck->fd = unsorted_chunks (av);
3766
3767	/ Take now instead of binning if exact fit /
3768
3769	if (size == nb)
3770	{
3771	set_inuse_bit_at_offset (victim, size);
3772	if (av != &main_arena)
3773	set_non_main_arena (victim);
3774	#if USE_TCACHE
3775	/ Fill cache first, return to user only if cache fills.*
3776	We may return one of these chunks later. /*
3777	if (tcache_nb
3778	&& tcache->counts[tc_idx] < mp_.tcache_count)
3779	{
3780	tcache_put (victim, tc_idx);
3781	return_cached = `1`;
3782	continue;
3783	}
3784	else
3785	{
3786	#endif
3787	check_malloced_chunk (av, victim, nb);
3788	void *p = chunk2mem (victim);
3789	alloc_perturb (p, bytes);
3790	return p;
3791	#if USE_TCACHE
3792	}
3793	#endif
3794	}
3795
3796	/ place chunk in bin /
3797
3798	if (in_smallbin_range (size))
3799	{
3800	victim_index = smallbin_index (size);
3801	bck = bin_at (av, victim_index);
3802	fwd = bck->fd;
3803	}
3804	else
3805	{
3806	victim_index = largebin_index (size);
3807	bck = bin_at (av, victim_index);
3808	fwd = bck->fd;
3809
3810	/ maintain large bins in sorted order /
3811	if (fwd != bck)
3812	{
3813	/ Or with inuse bit to speed comparisons /
3814	size \|= PREV_INUSE;
3815	/ if smaller than smallest, bypass loop below /
3816	assert (chunk_main_arena (bck->bk));
3817	if ((unsigned long) (size)
3818	< (unsigned long) chunksize_nomask (bck->bk))
3819	{
3820	fwd = bck;
3821	bck = bck->bk;
3822
3823	victim->fd_nextsize = fwd->fd;
3824	victim->bk_nextsize = fwd->fd->bk_nextsize;
3825	fwd->fd->bk_nextsize = victim->bk_nextsize->fd_nextsize = victim;
3826	}
3827	else
3828	{
3829	assert (chunk_main_arena (fwd));
3830	while ((unsigned long) size < chunksize_nomask (fwd))
3831	{
3832	fwd = fwd->fd_nextsize;
3833	assert (chunk_main_arena (fwd));
3834	}
3835
3836	if ((unsigned long) size
3837	== (unsigned long) chunksize_nomask (fwd))
3838	/ Always insert in the second position. /
3839	fwd = fwd->fd;
3840	else
3841	{
3842	victim->fd_nextsize = fwd;
3843	victim->bk_nextsize = fwd->bk_nextsize;
3844	fwd->bk_nextsize = victim;
3845	victim->bk_nextsize->fd_nextsize = victim;
3846	}
3847	bck = fwd->bk;
3848	}
3849	}
3850	else
3851	victim->fd_nextsize = victim->bk_nextsize = victim;
3852	}
3853
3854	mark_bin (av, victim_index);
3855	victim->bk = bck;
3856	victim->fd = fwd;
3857	fwd->bk = victim;
3858	bck->fd = victim;
3859
3860	#if USE_TCACHE
3861	/ If we've processed as many chunks as we're allowed while*
3862	filling the cache, return one of the cached ones. /*
3863	++tcache_unsorted_count;
3864	if (return_cached
3865	&& mp_.tcache_unsorted_limit > `0`
3866	&& tcache_unsorted_count > mp_.tcache_unsorted_limit)
3867	{
3868	return tcache_get (tc_idx);
3869	}
3870	#endif
3871
3872	#define MAX_ITERS 10000
3873	if (++iters >= MAX_ITERS)
3874	break;
3875	}
3876
3877	#if USE_TCACHE
3878	/ If all the small chunks we found ended up cached, return one now. /
3879	if (return_cached)
3880	{
3881	return tcache_get (tc_idx);
3882	}
3883	#endif
3884
3885	/*
3886	If a large request, scan through the chunks of current bin in
3887	sorted order to find smallest that fits. Use the skip list for this.
3888	*/
3889
3890	if (!in_smallbin_range (nb))
3891	{
3892	bin = bin_at (av, idx);
3893
3894	/ skip scan if empty or largest chunk is too small /
3895	if ((victim = first (bin)) != bin
3896	&& (unsigned long) chunksize_nomask (victim)
3897	>= (unsigned long) (nb))
3898	{
3899	victim = victim->bk_nextsize;
3900	while (((unsigned long) (size = chunksize (victim)) <
3901	(unsigned long) (nb)))
3902	victim = victim->bk_nextsize;
3903
3904	/ Avoid removing the first entry for a size so that the skip*
3905	list does not have to be rerouted. /*
3906	if (victim != last (bin)
3907	&& chunksize_nomask (victim)
3908	== chunksize_nomask (victim->fd))
3909	victim = victim->fd;
3910
3911	remainder_size = size - nb;
3912	unlink (av, victim, bck, fwd);
3913
3914	/ Exhaust /
3915	if (remainder_size < MINSIZE)
3916	{
3917	set_inuse_bit_at_offset (victim, size);
3918	if (av != &main_arena)
3919	set_non_main_arena (victim);
3920	}
3921	/ Split /
3922	else
3923	{
3924	remainder = chunk_at_offset (victim, nb);
3925	/ We cannot assume the unsorted list is empty and therefore*
3926	have to perform a complete insert here. /*
3927	bck = unsorted_chunks (av);
3928	fwd = bck->fd;
3929	if (__glibc_unlikely (fwd->bk != bck))
3930	malloc_printerr ("malloc(): corrupted unsorted chunks");
3931	remainder->bk = bck;
3932	remainder->fd = fwd;
3933	bck->fd = remainder;
3934	fwd->bk = remainder;
3935	if (!in_smallbin_range (remainder_size))
3936	{
3937	remainder->fd_nextsize = NULL;
3938	remainder->bk_nextsize = NULL;
3939	}
3940	set_head (victim, nb \| PREV_INUSE \|
3941	(av != &main_arena ? NON_MAIN_ARENA : `0`));
3942	set_head (remainder, remainder_size \| PREV_INUSE);
3943	set_foot (remainder, remainder_size);
3944	}
3945	check_malloced_chunk (av, victim, nb);
3946	void *p = chunk2mem (victim);
3947	alloc_perturb (p, bytes);
3948	return p;
3949	}
3950	}
3951
3952	/*
3953	Search for a chunk by scanning bins, starting with next largest
3954	bin. This search is strictly by best-fit; i.e., the smallest
3955	(with ties going to approximately the least recently used) chunk
3956	that fits is selected.
3957
3958	The bitmap avoids needing to check that most blocks are nonempty.
3959	The particular case of skipping all bins during warm-up phases
3960	when no chunks have been returned yet is faster than it might look.
3961	*/
3962
3963	++idx;
3964	bin = bin_at (av, idx);
3965	block = idx2block (idx);
3966	map = av->binmap[block];
3967	bit = idx2bit (idx);
3968
3969	for (;; )
3970	{
3971	/ Skip rest of block if there are no more set bits in this block. /
3972	if (bit > map \|\| bit == `0`)
3973	{
3974	do
3975	{
3976	if (++block >= BINMAPSIZE) / out of bins /
3977	goto use_top;
3978	}
3979	while ((map = av->binmap[block]) == `0`);
3980
3981	bin = bin_at (av, (block << BINMAPSHIFT));
3982	bit = `1`;
3983	}
3984
3985	/ Advance to bin with set bit. There must be one. /
3986	while ((bit & map) == `0`)
3987	{
3988	bin = next_bin (bin);
3989	bit <<= `1`;
3990	assert (bit != `0`);
3991	}
3992
3993	/ Inspect the bin. It is likely to be non-empty /
3994	victim = last (bin);
3995
3996	/ If a false alarm (empty bin), clear the bit. /
3997	if (victim == bin)
3998	{
3999	av->binmap[block] = map &= ~bit; / Write through /
4000	bin = next_bin (bin);
4001	bit <<= `1`;
4002	}
4003
4004	else
4005	{
4006	size = chunksize (victim);
4007
4008	/ We know the first chunk in this bin is big enough to use. /
4009	assert ((unsigned long) (size) >= (unsigned long) (nb));
4010
4011	remainder_size = size - nb;
4012
4013	/ unlink /
4014	unlink (av, victim, bck, fwd);
4015
4016	/ Exhaust /
4017	if (remainder_size < MINSIZE)
4018	{
4019	set_inuse_bit_at_offset (victim, size);
4020	if (av != &main_arena)
4021	set_non_main_arena (victim);
4022	}
4023
4024	/ Split /
4025	else
4026	{
4027	remainder = chunk_at_offset (victim, nb);
4028
4029	/ We cannot assume the unsorted list is empty and therefore*
4030	have to perform a complete insert here. /*
4031	bck = unsorted_chunks (av);
4032	fwd = bck->fd;
4033	if (__glibc_unlikely (fwd->bk != bck))
4034	malloc_printerr ("malloc(): corrupted unsorted chunks 2");
4035	remainder->bk = bck;
4036	remainder->fd = fwd;
4037	bck->fd = remainder;
4038	fwd->bk = remainder;
4039
4040	/ advertise as last remainder /
4041	if (in_smallbin_range (nb))
4042	av->last_remainder = remainder;
4043	if (!in_smallbin_range (remainder_size))
4044	{
4045	remainder->fd_nextsize = NULL;
4046	remainder->bk_nextsize = NULL;
4047	}
4048	set_head (victim, nb \| PREV_INUSE \|
4049	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4050	set_head (remainder, remainder_size \| PREV_INUSE);
4051	set_foot (remainder, remainder_size);
4052	}
4053	check_malloced_chunk (av, victim, nb);
4054	void *p = chunk2mem (victim);
4055	alloc_perturb (p, bytes);
4056	return p;
4057	}
4058	}
4059
4060	use_top:
4061	/*
4062	If large enough, split off the chunk bordering the end of memory
4063	(held in av->top). Note that this is in accord with the best-fit
4064	search rule. In effect, av->top is treated as larger (and thus
4065	less well fitting) than any other available chunk since it can
4066	be extended to be as large as necessary (up to system
4067	limitations).
4068
4069	We require that av->top always exists (i.e., has size >=
4070	MINSIZE) after initialization, so if it would otherwise be
4071	exhausted by current request, it is replenished. (The main
4072	reason for ensuring it exists is that we may need MINSIZE space
4073	to put in fenceposts in sysmalloc.)
4074	*/
4075
4076	victim = av->top;
4077	size = chunksize (victim);
4078
4079	if ((unsigned long) (size) >= (unsigned long) (nb + MINSIZE))
4080	{
4081	remainder_size = size - nb;
4082	remainder = chunk_at_offset (victim, nb);
4083	av->top = remainder;
4084	set_head (victim, nb \| PREV_INUSE \|
4085	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4086	set_head (remainder, remainder_size \| PREV_INUSE);
4087
4088	check_malloced_chunk (av, victim, nb);
4089	void *p = chunk2mem (victim);
4090	alloc_perturb (p, bytes);
4091	return p;
4092	}
4093
4094	/ When we are using atomic ops to free fast chunks we can get*
4095	here for all block sizes. /*
4096	else if (atomic_load_relaxed (&av->have_fastchunks))
4097	{
4098	malloc_consolidate (av);
4099	/ restore original bin index /
4100	if (in_smallbin_range (nb))
4101	idx = smallbin_index (nb);
4102	else
4103	idx = largebin_index (nb);
4104	}
4105
4106	/*
4107	Otherwise, relay to handle system-dependent cases
4108	*/
4109	else
4110	{
4111	void *p = sysmalloc (nb, av);
4112	if (p != NULL)
4113	alloc_perturb (p, bytes);
4114	return p;
4115	}
4116	}
4117	}
4118
4119	/*
4120	------------------------------ free ------------------------------
4121	*/
4122
4123	static void
4124	_int_free (mstate av, mchunkptr p, int have_lock)
4125	{
4126	INTERNAL_SIZE_T size; / its size /
4127	mfastbinptr fb; /* associated fastbin /
4128	mchunkptr nextchunk; / next contiguous chunk /
4129	INTERNAL_SIZE_T nextsize; / its size /
4130	int nextinuse; / true if nextchunk is used /
4131	INTERNAL_SIZE_T prevsize; / size of previous contiguous chunk /
4132	mchunkptr bck; / misc temp for linking /
4133	mchunkptr fwd; / misc temp for linking /
4134
4135	size = chunksize (p);
4136
4137	/ Little security check which won't hurt performance: the*
4138	allocator never wrapps around at the end of the address space.
4139	Therefore we can exclude some size values which might appear
4140	here by accident or by "design" from some intruder. /*
4141	if (__builtin_expect ((uintptr_t) p > (uintptr_t) -size, `0`)
4142	\|\| __builtin_expect (misaligned_chunk (p), `0`))
4143	malloc_printerr ("free(): invalid pointer");
4144	/ We know that each chunk is at least MINSIZE bytes in size or a*
4145	multiple of MALLOC_ALIGNMENT. /*
4146	if (__glibc_unlikely (size < MINSIZE \|\| !aligned_OK (size)))
4147	malloc_printerr ("free(): invalid size");
4148
4149	check_inuse_chunk(av, p);
4150
4151	#if USE_TCACHE
4152	{
4153	size_t tc_idx = csize2tidx (size);
4154
4155	if (tcache
4156	&& tc_idx < mp_.tcache_bins
4157	&& tcache->counts[tc_idx] < mp_.tcache_count)
4158	{
4159	tcache_put (p, tc_idx);
4160	return;
4161	}
4162	}
4163	#endif
4164
4165	/*
4166	If eligible, place chunk on a fastbin so it can be found
4167	and used quickly in malloc.
4168	*/
4169
4170	if ((unsigned long)(size) <= (unsigned long)(get_max_fast ())
4171
4172	#if TRIM_FASTBINS
4173	/*
4174	If TRIM_FASTBINS set, don't place chunks
4175	bordering top into fastbins
4176	*/
4177	&& (chunk_at_offset(p, size) != av->top)
4178	#endif
4179	) {
4180
4181	if (__builtin_expect (chunksize_nomask (chunk_at_offset (p, size))
4182	<= `2` * SIZE_SZ, `0`)
4183	\|\| __builtin_expect (chunksize (chunk_at_offset (p, size))
4184	>= av->system_mem, `0`))
4185	{
4186	bool fail = true;
4187	/ We might not have a lock at this point and concurrent modifications*
4188	of system_mem might result in a false positive. Redo the test after
4189	getting the lock. /*
4190	if (!have_lock)
4191	{
4192	__libc_lock_lock (av->mutex);
4193	fail = (chunksize_nomask (chunk_at_offset (p, size)) <= `2` * SIZE_SZ
4194	\|\| chunksize (chunk_at_offset (p, size)) >= av->system_mem);
4195	__libc_lock_unlock (av->mutex);
4196	}
4197
4198	if (fail)
4199	malloc_printerr ("free(): invalid next size (fast)");
4200	}
4201
4202	free_perturb (chunk2mem(p), size - `2` * SIZE_SZ);
4203
4204	atomic_store_relaxed (&av->have_fastchunks, true);
4205	unsigned int idx = fastbin_index(size);
4206	fb = &fastbin (av, idx);
4207
4208	/ Atomically link P to its fastbin: P->FD = FB; FB = P; /
4209	mchunkptr old = *fb, old2;
4210
4211	if (SINGLE_THREAD_P)
4212	{
4213	/ Check that the top of the bin is not the record we are going to*
4214	add (i.e., double free). /*
4215	if (__builtin_expect (old == p, `0`))
4216	malloc_printerr ("double free or corruption (fasttop)");
4217	p->fd = old;
4218	*fb = p;
4219	}
4220	else
4221	do
4222	{
4223	/ Check that the top of the bin is not the record we are going to*
4224	add (i.e., double free). /*
4225	if (__builtin_expect (old == p, `0`))
4226	malloc_printerr ("double free or corruption (fasttop)");
4227	p->fd = old2 = old;
4228	}
4229	while ((old = catomic_compare_and_exchange_val_rel (fb, p, old2))
4230	!= old2);
4231
4232	/ Check that size of fastbin chunk at the top is the same as*
4233	size of the chunk that we are adding. We can dereference OLD
4234	only if we have the lock, otherwise it might have already been
4235	allocated again. /*
4236	if (have_lock && old != NULL
4237	&& __builtin_expect (fastbin_index (chunksize (old)) != idx, `0`))
4238	malloc_printerr ("invalid fastbin entry (free)");
4239	}
4240
4241	/*
4242	Consolidate other non-mmapped chunks as they arrive.
4243	*/
4244
4245	else if (!chunk_is_mmapped(p)) {
4246
4247	/ If we're single-threaded, don't lock the arena. /
4248	if (SINGLE_THREAD_P)
4249	have_lock = true;
4250
4251	if (!have_lock)
4252	__libc_lock_lock (av->mutex);
4253
4254	nextchunk = chunk_at_offset(p, size);
4255
4256	/ Lightweight tests: check whether the block is already the*
4257	top block. /*
4258	if (__glibc_unlikely (p == av->top))
4259	malloc_printerr ("double free or corruption (top)");
4260	/ Or whether the next chunk is beyond the boundaries of the arena. /
4261	if (__builtin_expect (contiguous (av)
4262	&& (char *) nextchunk
4263	>= ((char *) av->top + chunksize(av->top)), `0`))
4264	malloc_printerr ("double free or corruption (out)");
4265	/ Or whether the block is actually not marked used. /
4266	if (__glibc_unlikely (!prev_inuse(nextchunk)))
4267	malloc_printerr ("double free or corruption (!prev)");
4268
4269	nextsize = chunksize(nextchunk);
4270	if (__builtin_expect (chunksize_nomask (nextchunk) <= `2` * SIZE_SZ, `0`)
4271	\|\| __builtin_expect (nextsize >= av->system_mem, `0`))
4272	malloc_printerr ("free(): invalid next size (normal)");
4273
4274	free_perturb (chunk2mem(p), size - `2` * SIZE_SZ);
4275
4276	/ consolidate backward /
4277	if (!prev_inuse(p)) {
4278	prevsize = prev_size (p);
4279	size += prevsize;
4280	p = chunk_at_offset(p, -((long) prevsize));
4281	unlink(av, p, bck, fwd);
4282	}
4283
4284	if (nextchunk != av->top) {
4285	/ get and clear inuse bit /
4286	nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
4287
4288	/ consolidate forward /
4289	if (!nextinuse) {
4290	unlink(av, nextchunk, bck, fwd);
4291	size += nextsize;
4292	} else
4293	clear_inuse_bit_at_offset(nextchunk, `0`);
4294
4295	/*
4296	Place the chunk in unsorted chunk list. Chunks are
4297	not placed into regular bins until after they have
4298	been given one chance to be used in malloc.
4299	*/
4300
4301	bck = unsorted_chunks(av);
4302	fwd = bck->fd;
4303	if (__glibc_unlikely (fwd->bk != bck))
4304	malloc_printerr ("free(): corrupted unsorted chunks");
4305	p->fd = fwd;
4306	p->bk = bck;
4307	if (!in_smallbin_range(size))
4308	{
4309	p->fd_nextsize = NULL;
4310	p->bk_nextsize = NULL;
4311	}
4312	bck->fd = p;
4313	fwd->bk = p;
4314
4315	set_head(p, size \| PREV_INUSE);
4316	set_foot(p, size);
4317
4318	check_free_chunk(av, p);
4319	}
4320
4321	/*
4322	If the chunk borders the current high end of memory,
4323	consolidate into top
4324	*/
4325
4326	else {
4327	size += nextsize;
4328	set_head(p, size \| PREV_INUSE);
4329	av->top = p;
4330	check_chunk(av, p);
4331	}
4332
4333	/*
4334	If freeing a large space, consolidate possibly-surrounding
4335	chunks. Then, if the total unused topmost memory exceeds trim
4336	threshold, ask malloc_trim to reduce top.
4337
4338	Unless max_fast is 0, we don't know if there are fastbins
4339	bordering top, so we cannot tell for sure whether threshold
4340	has been reached unless fastbins are consolidated. But we
4341	don't want to consolidate on each free. As a compromise,
4342	consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD
4343	is reached.
4344	*/
4345
4346	if ((unsigned long)(size) >= FASTBIN_CONSOLIDATION_THRESHOLD) {
4347	if (atomic_load_relaxed (&av->have_fastchunks))
4348	malloc_consolidate(av);
4349
4350	if (av == &main_arena) {
4351	#ifndef MORECORE_CANNOT_TRIM
4352	if ((unsigned long)(chunksize(av->top)) >=
4353	(unsigned long)(mp_.trim_threshold))
4354	systrim(mp_.top_pad, av);
4355	#endif
4356	} else {
4357	/ Always try heap_trim(), even if the top chunk is not*
4358	large, because the corresponding heap might go away. /*
4359	heap_info *heap = heap_for_ptr(top(av));
4360
4361	assert(heap->ar_ptr == av);
4362	heap_trim(heap, mp_.top_pad);
4363	}
4364	}
4365
4366	if (!have_lock)
4367	__libc_lock_unlock (av->mutex);
4368	}
4369	/*
4370	If the chunk was allocated via mmap, release via munmap().
4371	*/
4372
4373	else {
4374	munmap_chunk (p);
4375	}
4376	}
4377
4378	/*
4379	------------------------- malloc_consolidate -------------------------
4380
4381	malloc_consolidate is a specialized version of free() that tears
4382	down chunks held in fastbins. Free itself cannot be used for this
4383	purpose since, among other things, it might place chunks back onto
4384	fastbins. So, instead, we need to use a minor variant of the same
4385	code.
4386	*/
4387
4388	static void malloc_consolidate(mstate av)
4389	{
4390	mfastbinptr* fb; / current fastbin being consolidated /
4391	mfastbinptr* maxfb; / last fastbin (for loop control) /
4392	mchunkptr p; / current chunk being consolidated /
4393	mchunkptr nextp; / next chunk to consolidate /
4394	mchunkptr unsorted_bin; / bin header /
4395	mchunkptr first_unsorted; / chunk to link to /
4396
4397	/ These have same use as in free() /
4398	mchunkptr nextchunk;
4399	INTERNAL_SIZE_T size;
4400	INTERNAL_SIZE_T nextsize;
4401	INTERNAL_SIZE_T prevsize;
4402	int nextinuse;
4403	mchunkptr bck;
4404	mchunkptr fwd;
4405
4406	atomic_store_relaxed (&av->have_fastchunks, false);
4407
4408	unsorted_bin = unsorted_chunks(av);
4409
4410	/*
4411	Remove each chunk from fast bin and consolidate it, placing it
4412	then in unsorted bin. Among other reasons for doing this,
4413	placing in unsorted bin avoids needing to calculate actual bins
4414	until malloc is sure that chunks aren't immediately going to be
4415	reused anyway.
4416	*/
4417
4418	maxfb = &fastbin (av, NFASTBINS - `1`);
4419	fb = &fastbin (av, `0`);
4420	do {
4421	p = atomic_exchange_acq (fb, NULL);
4422	if (p != `0`) {
4423	do {
4424	{
4425	unsigned int idx = fastbin_index (chunksize (p));
4426	if ((&fastbin (av, idx)) != fb)
4427	malloc_printerr ("malloc_consolidate(): invalid chunk size");
4428	}
4429
4430	check_inuse_chunk(av, p);
4431	nextp = p->fd;
4432
4433	/ Slightly streamlined version of consolidation code in free() /
4434	size = chunksize (p);
4435	nextchunk = chunk_at_offset(p, size);
4436	nextsize = chunksize(nextchunk);
4437
4438	if (!prev_inuse(p)) {
4439	prevsize = prev_size (p);
4440	size += prevsize;
4441	p = chunk_at_offset(p, -((long) prevsize));
4442	unlink(av, p, bck, fwd);
4443	}
4444
4445	if (nextchunk != av->top) {
4446	nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
4447
4448	if (!nextinuse) {
4449	size += nextsize;
4450	unlink(av, nextchunk, bck, fwd);
4451	} else
4452	clear_inuse_bit_at_offset(nextchunk, `0`);
4453
4454	first_unsorted = unsorted_bin->fd;
4455	unsorted_bin->fd = p;
4456	first_unsorted->bk = p;
4457
4458	if (!in_smallbin_range (size)) {
4459	p->fd_nextsize = NULL;
4460	p->bk_nextsize = NULL;
4461	}
4462
4463	set_head(p, size \| PREV_INUSE);
4464	p->bk = unsorted_bin;
4465	p->fd = first_unsorted;
4466	set_foot(p, size);
4467	}
4468
4469	else {
4470	size += nextsize;
4471	set_head(p, size \| PREV_INUSE);
4472	av->top = p;
4473	}
4474
4475	} while ( (p = nextp) != `0`);
4476
4477	}
4478	} while (fb++ != maxfb);
4479	}
4480
4481	/*
4482	------------------------------ realloc ------------------------------
4483	*/
4484
4485	void*
4486	_int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize,
4487	INTERNAL_SIZE_T nb)
4488	{
4489	mchunkptr newp; / chunk to return /
4490	INTERNAL_SIZE_T newsize; / its size /
4491	void* newmem; / corresponding user mem /
4492
4493	mchunkptr next; / next contiguous chunk after oldp /
4494
4495	mchunkptr remainder; / extra space at end of newp /
4496	unsigned long remainder_size; / its size /
4497
4498	mchunkptr bck; / misc temp for linking /
4499	mchunkptr fwd; / misc temp for linking /
4500
4501	unsigned long copysize; / bytes to copy /
4502	unsigned int ncopies; / INTERNAL_SIZE_T words to copy /
4503	INTERNAL_SIZE_T* s; / copy source /
4504	INTERNAL_SIZE_T* d; / copy destination /
4505
4506	/ oldmem size /
4507	if (__builtin_expect (chunksize_nomask (oldp) <= `2` * SIZE_SZ, `0`)
4508	\|\| __builtin_expect (oldsize >= av->system_mem, `0`))
4509	malloc_printerr ("realloc(): invalid old size");
4510
4511	check_inuse_chunk (av, oldp);
4512
4513	/ All callers already filter out mmap'ed chunks. /
4514	assert (!chunk_is_mmapped (oldp));
4515
4516	next = chunk_at_offset (oldp, oldsize);
4517	INTERNAL_SIZE_T nextsize = chunksize (next);
4518	if (__builtin_expect (chunksize_nomask (next) <= `2` * SIZE_SZ, `0`)
4519	\|\| __builtin_expect (nextsize >= av->system_mem, `0`))
4520	malloc_printerr ("realloc(): invalid next size");
4521
4522	if ((unsigned long) (oldsize) >= (unsigned long) (nb))
4523	{
4524	/ already big enough; split below /
4525	newp = oldp;
4526	newsize = oldsize;
4527	}
4528
4529	else
4530	{
4531	/ Try to expand forward into top /
4532	if (next == av->top &&
4533	(unsigned long) (newsize = oldsize + nextsize) >=
4534	(unsigned long) (nb + MINSIZE))
4535	{
4536	set_head_size (oldp, nb \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4537	av->top = chunk_at_offset (oldp, nb);
4538	set_head (av->top, (newsize - nb) \| PREV_INUSE);
4539	check_inuse_chunk (av, oldp);
4540	return chunk2mem (oldp);
4541	}
4542
4543	/ Try to expand forward into next chunk; split off remainder below /
4544	else if (next != av->top &&
4545	!inuse (next) &&
4546	(unsigned long) (newsize = oldsize + nextsize) >=
4547	(unsigned long) (nb))
4548	{
4549	newp = oldp;
4550	unlink (av, next, bck, fwd);
4551	}
4552
4553	/ allocate, copy, free /
4554	else
4555	{
4556	newmem = _int_malloc (av, nb - MALLOC_ALIGN_MASK);
4557	if (newmem == `0`)
4558	return `0`; / propagate failure /
4559
4560	newp = mem2chunk (newmem);
4561	newsize = chunksize (newp);
4562
4563	/*
4564	Avoid copy if newp is next chunk after oldp.
4565	*/
4566	if (newp == next)
4567	{
4568	newsize += oldsize;
4569	newp = oldp;
4570	}
4571	else
4572	{
4573	/*
4574	Unroll copy of <= 36 bytes (72 if 8byte sizes)
4575	We know that contents have an odd number of
4576	INTERNAL_SIZE_T-sized words; minimally 3.
4577	*/
4578
4579	copysize = oldsize - SIZE_SZ;
4580	s = (INTERNAL_SIZE_T *) (chunk2mem (oldp));
4581	d = (INTERNAL_SIZE_T *) (newmem);
4582	ncopies = copysize / sizeof (INTERNAL_SIZE_T);
4583	assert (ncopies >= `3`);
4584
4585	if (ncopies > `9`)
4586	memcpy (d, s, copysize);
4587
4588	else
4589	{
4590	(d + `0`) = (s + `0`);
4591	(d + `1`) = (s + `1`);
4592	(d + `2`) = (s + `2`);
4593	if (ncopies > `4`)
4594	{
4595	(d + `3`) = (s + `3`);
4596	(d + `4`) = (s + `4`);
4597	if (ncopies > `6`)
4598	{
4599	(d + `5`) = (s + `5`);
4600	(d + `6`) = (s + `6`);
4601	if (ncopies > `8`)
4602	{
4603	(d + `7`) = (s + `7`);
4604	(d + `8`) = (s + `8`);
4605	}
4606	}
4607	}
4608	}
4609
4610	_int_free (av, oldp, `1`);
4611	check_inuse_chunk (av, newp);
4612	return chunk2mem (newp);
4613	}
4614	}
4615	}
4616
4617	/ If possible, free extra space in old or extended chunk /
4618
4619	assert ((unsigned long) (newsize) >= (unsigned long) (nb));
4620
4621	remainder_size = newsize - nb;
4622
4623	if (remainder_size < MINSIZE) / not enough extra to split off /
4624	{
4625	set_head_size (newp, newsize \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4626	set_inuse_bit_at_offset (newp, newsize);
4627	}
4628	else / split remainder /
4629	{
4630	remainder = chunk_at_offset (newp, nb);
4631	set_head_size (newp, nb \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4632	set_head (remainder, remainder_size \| PREV_INUSE \|
4633	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4634	/ Mark remainder as inuse so free() won't complain /
4635	set_inuse_bit_at_offset (remainder, remainder_size);
4636	_int_free (av, remainder, `1`);
4637	}
4638
4639	check_inuse_chunk (av, newp);
4640	return chunk2mem (newp);
4641	}
4642
4643	/*
4644	------------------------------ memalign ------------------------------
4645	*/
4646
4647	static void *
4648	_int_memalign (mstate av, size_t alignment, size_t bytes)
4649	{
4650	INTERNAL_SIZE_T nb; / padded request size /
4651	char m; /* memory returned by malloc call /
4652	mchunkptr p; / corresponding chunk /
4653	char brk; /* alignment point within p /
4654	mchunkptr newp; / chunk to return /
4655	INTERNAL_SIZE_T newsize; / its size /
4656	INTERNAL_SIZE_T leadsize; / leading space before alignment point /
4657	mchunkptr remainder; / spare room at end to split off /
4658	unsigned long remainder_size; / its size /
4659	INTERNAL_SIZE_T size;
4660
4661
4662
4663	checked_request2size (bytes, nb);
4664
4665	/*
4666	Strategy: find a spot within that chunk that meets the alignment
4667	request, and then possibly free the leading and trailing space.
4668	*/
4669
4670
4671	/ Check for overflow. /
4672	if (nb > SIZE_MAX - alignment - MINSIZE)
4673	{
4674	__set_errno (ENOMEM);
4675	return `0`;
4676	}
4677
4678	/ Call malloc with worst case padding to hit alignment. /
4679
4680	m = (char *) (_int_malloc (av, nb + alignment + MINSIZE));
4681
4682	if (m == `0`)
4683	return `0`; / propagate failure /
4684
4685	p = mem2chunk (m);
4686
4687	if ((((unsigned long) (m)) % alignment) != `0`) / misaligned /
4688
4689	{ /*
4690	Find an aligned spot inside chunk. Since we need to give back
4691	leading space in a chunk of at least MINSIZE, if the first
4692	calculation places us at a spot with less than MINSIZE leader,
4693	we can move to the next aligned spot -- we've allocated enough
4694	total room so that this is always possible.
4695	*/
4696	brk = (char ) mem2chunk (((unsigned* long) (m + alignment - `1`)) &
4697	- ((signed long) alignment));
4698	if ((unsigned long) (brk - (char *) (p)) < MINSIZE)
4699	brk += alignment;
4700
4701	newp = (mchunkptr) brk;
4702	leadsize = brk - (char *) (p);
4703	newsize = chunksize (p) - leadsize;
4704
4705	/ For mmapped chunks, just adjust offset /
4706	if (chunk_is_mmapped (p))
4707	{
4708	set_prev_size (newp, prev_size (p) + leadsize);
4709	set_head (newp, newsize \| IS_MMAPPED);
4710	return chunk2mem (newp);
4711	}
4712
4713	/ Otherwise, give back leader, use the rest /
4714	set_head (newp, newsize \| PREV_INUSE \|
4715	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4716	set_inuse_bit_at_offset (newp, newsize);
4717	set_head_size (p, leadsize \| (av != &main_arena ? NON_MAIN_ARENA : `0`));
4718	_int_free (av, p, `1`);
4719	p = newp;
4720
4721	assert (newsize >= nb &&
4722	(((unsigned long) (chunk2mem (p))) % alignment) == `0`);
4723	}
4724
4725	/ Also give back spare room at the end /
4726	if (!chunk_is_mmapped (p))
4727	{
4728	size = chunksize (p);
4729	if ((unsigned long) (size) > (unsigned long) (nb + MINSIZE))
4730	{
4731	remainder_size = size - nb;
4732	remainder = chunk_at_offset (p, nb);
4733	set_head (remainder, remainder_size \| PREV_INUSE \|
4734	(av != &main_arena ? NON_MAIN_ARENA : `0`));
4735	set_head_size (p, nb);
4736	_int_free (av, remainder, `1`);
4737	}
4738	}
4739
4740	check_inuse_chunk (av, p);
4741	return chunk2mem (p);
4742	}
4743
4744
4745	/*
4746	------------------------------ malloc_trim ------------------------------
4747	*/
4748
4749	static int
4750	mtrim (mstate av, size_t pad)
4751	{
4752	/ Ensure all blocks are consolidated. /
4753	malloc_consolidate (av);
4754
4755	const size_t ps = GLRO (dl_pagesize);
4756	int psindex = bin_index (ps);
4757	const size_t psm1 = ps - `1`;
4758
4759	int result = `0`;
4760	for (int i = `1`; i < NBINS; ++i)
4761	if (i == `1` \|\| i >= psindex)
4762	{
4763	mbinptr bin = bin_at (av, i);
4764
4765	for (mchunkptr p = last (bin); p != bin; p = p->bk)
4766	{
4767	INTERNAL_SIZE_T size = chunksize (p);
4768
4769	if (size > psm1 + sizeof (struct malloc_chunk))
4770	{
4771	/ See whether the chunk contains at least one unused page. /
4772	char paligned_mem = (char* *) (((uintptr_t) p
4773	+ sizeof (struct malloc_chunk)
4774	+ psm1) & ~psm1);
4775
4776	assert ((char ) chunk2mem (p) + `4` SIZE_SZ <= paligned_mem);
4777	assert ((char *) p + size > paligned_mem);
4778
4779	/ This is the size we could potentially free. /
4780	size -= paligned_mem - (char *) p;
4781
4782	if (size > psm1)
4783	{
4784	#if MALLOC_DEBUG
4785	/ When debugging we simulate destroying the memory*
4786	content. /*
4787	memset (paligned_mem, `0x89`, size & ~psm1);
4788	#endif
4789	__madvise (paligned_mem, size & ~psm1, MADV_DONTNEED);
4790
4791	result = `1`;
4792	}
4793	}
4794	}
4795	}
4796
4797	#ifndef MORECORE_CANNOT_TRIM
4798	return result \| (av == &main_arena ? systrim (pad, av) : `0`);
4799
4800	#else
4801	return result;
4802	#endif
4803	}
4804
4805
4806	int
4807	__malloc_trim (size_t s)
4808	{
4809	int result = `0`;
4810
4811	if (__malloc_initialized < `0`)
4812	ptmalloc_init ();
4813
4814	mstate ar_ptr = &main_arena;
4815	do
4816	{
4817	__libc_lock_lock (ar_ptr->mutex);
4818	result \|= mtrim (ar_ptr, s);
4819	__libc_lock_unlock (ar_ptr->mutex);
4820
4821	ar_ptr = ar_ptr->next;
4822	}
4823	while (ar_ptr != &main_arena);
4824
4825	return result;
4826	}
4827
4828
4829	/*
4830	------------------------- malloc_usable_size -------------------------
4831	*/
4832
4833	static size_t
4834	musable (void *mem)
4835	{
4836	mchunkptr p;
4837	if (mem != `0`)
4838	{
4839	p = mem2chunk (mem);
4840
4841	if (__builtin_expect (using_malloc_checking == `1`, `0`))
4842	return malloc_check_get_size (p);
4843
4844	if (chunk_is_mmapped (p))
4845	{
4846	if (DUMPED_MAIN_ARENA_CHUNK (p))
4847	return chunksize (p) - SIZE_SZ;
4848	else
4849	return chunksize (p) - `2` * SIZE_SZ;
4850	}
4851	else if (inuse (p))
4852	return chunksize (p) - SIZE_SZ;
4853	}
4854	return `0`;
4855	}
4856
4857
4858	size_t
4859	__malloc_usable_size (void *m)
4860	{
4861	size_t result;
4862
4863	result = musable (m);
4864	return result;
4865	}
4866
4867	/*
4868	------------------------------ mallinfo ------------------------------
4869	Accumulate malloc statistics for arena AV into M.
4870	*/
4871
4872	static void
4873	int_mallinfo (mstate av, struct mallinfo *m)
4874	{
4875	size_t i;
4876	mbinptr b;
4877	mchunkptr p;
4878	INTERNAL_SIZE_T avail;
4879	INTERNAL_SIZE_T fastavail;
4880	int nblocks;
4881	int nfastblocks;
4882
4883	check_malloc_state (av);
4884
4885	/ Account for top /
4886	avail = chunksize (av->top);
4887	nblocks = `1`; / top always exists /
4888
4889	/ traverse fastbins /
4890	nfastblocks = `0`;
4891	fastavail = `0`;
4892
4893	for (i = `0`; i < NFASTBINS; ++i)
4894	{
4895	for (p = fastbin (av, i); p != `0`; p = p->fd)
4896	{
4897	++nfastblocks;
4898	fastavail += chunksize (p);
4899	}
4900	}
4901
4902	avail += fastavail;
4903
4904	/ traverse regular bins /
4905	for (i = `1`; i < NBINS; ++i)
4906	{
4907	b = bin_at (av, i);
4908	for (p = last (b); p != b; p = p->bk)
4909	{
4910	++nblocks;
4911	avail += chunksize (p);
4912	}
4913	}
4914
4915	m->smblks += nfastblocks;
4916	m->ordblks += nblocks;
4917	m->fordblks += avail;
4918	m->uordblks += av->system_mem - avail;
4919	m->arena += av->system_mem;
4920	m->fsmblks += fastavail;
4921	if (av == &main_arena)
4922	{
4923	m->hblks = mp_.n_mmaps;
4924	m->hblkhd = mp_.mmapped_mem;
4925	m->usmblks = `0`;
4926	m->keepcost = chunksize (av->top);
4927	}
4928	}
4929
4930
4931	struct mallinfo
4932	__libc_mallinfo (void)
4933	{
4934	struct mallinfo m;
4935	mstate ar_ptr;
4936
4937	if (__malloc_initialized < `0`)
4938	ptmalloc_init ();
4939
4940	memset (&m, `0`, sizeof (m));
4941	ar_ptr = &main_arena;
4942	do
4943	{
4944	__libc_lock_lock (ar_ptr->mutex);
4945	int_mallinfo (ar_ptr, &m);
4946	__libc_lock_unlock (ar_ptr->mutex);
4947
4948	ar_ptr = ar_ptr->next;
4949	}
4950	while (ar_ptr != &main_arena);
4951
4952	return m;
4953	}
4954
4955	/*
4956	------------------------------ malloc_stats ------------------------------
4957	*/
4958
4959	void
4960	__malloc_stats (void)
4961	{
4962	int i;
4963	mstate ar_ptr;
4964	unsigned int in_use_b = mp_.mmapped_mem, system_b = in_use_b;
4965
4966	if (__malloc_initialized < `0`)
4967	ptmalloc_init ();
4968	_IO_flockfile (stderr);
4969	int old_flags2 = stderr->_flags2;
4970	stderr->_flags2 \|= _IO_FLAGS2_NOTCANCEL;
4971	for (i = `0`, ar_ptr = &main_arena;; i++)
4972	{
4973	struct mallinfo mi;
4974
4975	memset (&mi, `0`, sizeof (mi));
4976	__libc_lock_lock (ar_ptr->mutex);
4977	int_mallinfo (ar_ptr, &mi);
4978	fprintf (stderr, "Arena %d:\n", i);
4979	fprintf (stderr, "system bytes = %10u\n", (unsigned int) mi.arena);
4980	fprintf (stderr, "in use bytes = %10u\n", (unsigned int) mi.uordblks);
4981	#if MALLOC_DEBUG > 1
4982	if (i > `0`)
4983	dump_heap (heap_for_ptr (top (ar_ptr)));
4984	#endif
4985	system_b += mi.arena;
4986	in_use_b += mi.uordblks;
4987	__libc_lock_unlock (ar_ptr->mutex);
4988	ar_ptr = ar_ptr->next;
4989	if (ar_ptr == &main_arena)
4990	break;
4991	}
4992	fprintf (stderr, "Total (incl. mmap):\n");
4993	fprintf (stderr, "system bytes = %10u\n", system_b);
4994	fprintf (stderr, "in use bytes = %10u\n", in_use_b);
4995	fprintf (stderr, "max mmap regions = %10u\n", (unsigned int) mp_.max_n_mmaps);
4996	fprintf (stderr, "max mmap bytes = %10lu\n",
4997	(unsigned long) mp_.max_mmapped_mem);
4998	stderr->_flags2 = old_flags2;
4999	_IO_funlockfile (stderr);
5000	}
5001
5002
5003	/*
5004	------------------------------ mallopt ------------------------------
5005	*/
5006	static inline int
5007	__always_inline
5008	do_set_trim_threshold (size_t value)
5009	{
5010	LIBC_PROBE (memory_mallopt_trim_threshold, `3`, value, mp_.trim_threshold,
5011	mp_.no_dyn_threshold);
5012	mp_.trim_threshold = value;
5013	mp_.no_dyn_threshold = `1`;
5014	return `1`;
5015	}
5016
5017	static inline int
5018	__always_inline
5019	do_set_top_pad (size_t value)
5020	{
5021	LIBC_PROBE (memory_mallopt_top_pad, `3`, value, mp_.top_pad,
5022	mp_.no_dyn_threshold);
5023	mp_.top_pad = value;
5024	mp_.no_dyn_threshold = `1`;
5025	return `1`;
5026	}
5027
5028	static inline int
5029	__always_inline
5030	do_set_mmap_threshold (size_t value)
5031	{
5032	/ Forbid setting the threshold too high. /
5033	if (value <= HEAP_MAX_SIZE / `2`)
5034	{
5035	LIBC_PROBE (memory_mallopt_mmap_threshold, `3`, value, mp_.mmap_threshold,
5036	mp_.no_dyn_threshold);
5037	mp_.mmap_threshold = value;
5038	mp_.no_dyn_threshold = `1`;
5039	return `1`;
5040	}
5041	return `0`;
5042	}
5043
5044	static inline int
5045	__always_inline
5046	do_set_mmaps_max (int32_t value)
5047	{
5048	LIBC_PROBE (memory_mallopt_mmap_max, `3`, value, mp_.n_mmaps_max,
5049	mp_.no_dyn_threshold);
5050	mp_.n_mmaps_max = value;
5051	mp_.no_dyn_threshold = `1`;
5052	return `1`;
5053	}
5054
5055	static inline int
5056	__always_inline
5057	do_set_mallopt_check (int32_t value)
5058	{
5059	return `1`;
5060	}
5061
5062	static inline int
5063	__always_inline
5064	do_set_perturb_byte (int32_t value)
5065	{
5066	LIBC_PROBE (memory_mallopt_perturb, `2`, value, perturb_byte);
5067	perturb_byte = value;
5068	return `1`;
5069	}
5070
5071	static inline int
5072	__always_inline
5073	do_set_arena_test (size_t value)
5074	{
5075	LIBC_PROBE (memory_mallopt_arena_test, `2`, value, mp_.arena_test);
5076	mp_.arena_test = value;
5077	return `1`;
5078	}
5079
5080	static inline int
5081	__always_inline
5082	do_set_arena_max (size_t value)
5083	{
5084	LIBC_PROBE (memory_mallopt_arena_max, `2`, value, mp_.arena_max);
5085	mp_.arena_max = value;
5086	return `1`;
5087	}
5088
5089	#if USE_TCACHE
5090	static inline int
5091	__always_inline
5092	do_set_tcache_max (size_t value)
5093	{
5094	if (value >= `0` && value <= MAX_TCACHE_SIZE)
5095	{
5096	LIBC_PROBE (memory_tunable_tcache_max_bytes, `2`, value, mp_.tcache_max_bytes);
5097	mp_.tcache_max_bytes = value;
5098	mp_.tcache_bins = csize2tidx (request2size(value)) + `1`;
5099	}
5100	return `1`;
5101	}
5102
5103	static inline int
5104	__always_inline
5105	do_set_tcache_count (size_t value)
5106	{
5107	LIBC_PROBE (memory_tunable_tcache_count, `2`, value, mp_.tcache_count);
5108	mp_.tcache_count = value;
5109	return `1`;
5110	}
5111
5112	static inline int
5113	__always_inline
5114	do_set_tcache_unsorted_limit (size_t value)
5115	{
5116	LIBC_PROBE (memory_tunable_tcache_unsorted_limit, `2`, value, mp_.tcache_unsorted_limit);
5117	mp_.tcache_unsorted_limit = value;
5118	return `1`;
5119	}
5120	#endif
5121
5122	int
5123	__libc_mallopt (int param_number, int value)
5124	{
5125	mstate av = &main_arena;
5126	int res = `1`;
5127
5128	if (__malloc_initialized < `0`)
5129	ptmalloc_init ();
5130	__libc_lock_lock (av->mutex);
5131
5132	LIBC_PROBE (memory_mallopt, `2`, param_number, value);
5133
5134	/ We must consolidate main arena before changing max_fast*
5135	(see definition of set_max_fast). /*
5136	malloc_consolidate (av);
5137
5138	switch (param_number)
5139	{
5140	case M_MXFAST:
5141	if (value >= `0` && value <= MAX_FAST_SIZE)
5142	{
5143	LIBC_PROBE (memory_mallopt_mxfast, `2`, value, get_max_fast ());
5144	set_max_fast (value);
5145	}
5146	else
5147	res = `0`;
5148	break;
5149
5150	case M_TRIM_THRESHOLD:
5151	do_set_trim_threshold (value);
5152	break;
5153
5154	case M_TOP_PAD:
5155	do_set_top_pad (value);
5156	break;
5157
5158	case M_MMAP_THRESHOLD:
5159	res = do_set_mmap_threshold (value);
5160	break;
5161
5162	case M_MMAP_MAX:
5163	do_set_mmaps_max (value);
5164	break;
5165
5166	case M_CHECK_ACTION:
5167	do_set_mallopt_check (value);
5168	break;
5169
5170	case M_PERTURB:
5171	do_set_perturb_byte (value);
5172	break;
5173
5174	case M_ARENA_TEST:
5175	if (value > `0`)
5176	do_set_arena_test (value);
5177	break;
5178
5179	case M_ARENA_MAX:
5180	if (value > `0`)
5181	do_set_arena_max (value);
5182	break;
5183	}
5184	__libc_lock_unlock (av->mutex);
5185	return res;
5186	}
5187	libc_hidden_def (__libc_mallopt)
5188
5189
5190	/*
5191	-------------------- Alternative MORECORE functions --------------------
5192	*/
5193
5194
5195	/*
5196	General Requirements for MORECORE.
5197
5198	The MORECORE function must have the following properties:
5199
5200	If MORECORE_CONTIGUOUS is false:
5201
5202	* MORECORE must allocate in multiples of pagesize. It will
5203	only be called with arguments that are multiples of pagesize.
5204
5205	* MORECORE(0) must return an address that is at least
5206	MALLOC_ALIGNMENT aligned. (Page-aligning always suffices.)
5207
5208	else (i.e. If MORECORE_CONTIGUOUS is true):
5209
5210	* Consecutive calls to MORECORE with positive arguments
5211	return increasing addresses, indicating that space has been
5212	contiguously extended.
5213
5214	* MORECORE need not allocate in multiples of pagesize.
5215	Calls to MORECORE need not have args of multiples of pagesize.
5216
5217	* MORECORE need not page-align.
5218
5219	In either case:
5220
5221	* MORECORE may allocate more memory than requested. (Or even less,
5222	but this will generally result in a malloc failure.)
5223
5224	* MORECORE must not allocate memory when given argument zero, but
5225	instead return one past the end address of memory from previous
5226	nonzero call. This malloc does NOT call MORECORE(0)
5227	until at least one call with positive arguments is made, so
5228	the initial value returned is not important.
5229
5230	* Even though consecutive calls to MORECORE need not return contiguous
5231	addresses, it must be OK for malloc'ed chunks to span multiple
5232	regions in those cases where they do happen to be contiguous.
5233
5234	* MORECORE need not handle negative arguments -- it may instead
5235	just return MORECORE_FAILURE when given negative arguments.
5236	Negative arguments are always multiples of pagesize. MORECORE
5237	must not misinterpret negative args as large positive unsigned
5238	args. You can suppress all such calls from even occurring by defining
5239	MORECORE_CANNOT_TRIM,
5240
5241	There is some variation across systems about the type of the
5242	argument to sbrk/MORECORE. If size_t is unsigned, then it cannot
5243	actually be size_t, because sbrk supports negative args, so it is
5244	normally the signed type of the same width as size_t (sometimes
5245	declared as "intptr_t", and sometimes "ptrdiff_t"). It doesn't much
5246	matter though. Internally, we use "long" as arguments, which should
5247	work across all reasonable possibilities.
5248
5249	Additionally, if MORECORE ever returns failure for a positive
5250	request, then mmap is used as a noncontiguous system allocator. This
5251	is a useful backup strategy for systems with holes in address spaces
5252	-- in this case sbrk cannot contiguously expand the heap, but mmap
5253	may be able to map noncontiguous space.
5254
5255	If you'd like mmap to ALWAYS be used, you can define MORECORE to be
5256	a function that always returns MORECORE_FAILURE.
5257
5258	If you are using this malloc with something other than sbrk (or its
5259	emulation) to supply memory regions, you probably want to set
5260	MORECORE_CONTIGUOUS as false. As an example, here is a custom
5261	allocator kindly contributed for pre-OSX macOS. It uses virtually
5262	but not necessarily physically contiguous non-paged memory (locked
5263	in, present and won't get swapped out). You can use it by
5264	uncommenting this section, adding some #includes, and setting up the
5265	appropriate defines above:
5266
5267	*#define MORECORE osMoreCore
5268	*#define MORECORE_CONTIGUOUS 0
5269
5270	There is also a shutdown routine that should somehow be called for
5271	cleanup upon program exit.
5272
5273	*#define MAX_POOL_ENTRIES 100
5274	#define MINIMUM_MORECORE_SIZE (64 1024)
5275	static int next_os_pool;
5276	void our_os_pools[MAX_POOL_ENTRIES];*
5277
5278	void osMoreCore(int size)*
5279	{
5280	void ptr = 0;*
5281	static void sbrk_top = 0;*
5282
5283	if (size > 0)
5284	{
5285	if (size < MINIMUM_MORECORE_SIZE)
5286	size = MINIMUM_MORECORE_SIZE;
5287	if (CurrentExecutionLevel() == kTaskLevel)
5288	ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
5289	if (ptr == 0)
5290	{
5291	return (void ) MORECORE_FAILURE;*
5292	}
5293	// save ptrs so they can be freed during cleanup
5294	our_os_pools[next_os_pool] = ptr;
5295	next_os_pool++;
5296	ptr = (void ) ((((unsigned long) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);*
5297	sbrk_top = (char ) ptr + size;*
5298	return ptr;
5299	}
5300	else if (size < 0)
5301	{
5302	// we don't currently support shrink behavior
5303	return (void ) MORECORE_FAILURE;*
5304	}
5305	else
5306	{
5307	return sbrk_top;
5308	}
5309	}
5310
5311	// cleanup any allocated memory pools
5312	// called as last thing before shutting down driver
5313
5314	void osCleanupMem(void)
5315	{
5316	void ptr;
5317
5318	for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
5319	if (ptr)*
5320	{
5321	PoolDeallocate(ptr);*
5322	* ptr = 0;
5323	}
5324	}
5325
5326	*/
5327
5328
5329	/ Helper code. /
5330
5331	extern char **__libc_argv attribute_hidden;
5332
5333	static void
5334	malloc_printerr (const char *str)
5335	{
5336	__libc_message (do_abort, "%s\n", str);
5337	__builtin_unreachable ();
5338	}
5339
5340	/ We need a wrapper function for one of the additions of POSIX. /
5341	int
5342	__posix_memalign (void **memptr, size_t alignment, size_t size)
5343	{
5344	void *mem;
5345
5346	/ Test whether the SIZE argument is valid. It must be a power of*
5347	two multiple of sizeof (void ). /
5348	if (alignment % sizeof (void *) != `0`
5349	\|\| !powerof2 (alignment / sizeof (void *))
5350	\|\| alignment == `0`)
5351	return EINVAL;
5352
5353
5354	void *address = RETURN_ADDRESS (`0`);
5355	mem = _mid_memalign (alignment, size, address);
5356
5357	if (mem != NULL)
5358	{
5359	*memptr = mem;
5360	return `0`;
5361	}
5362
5363	return ENOMEM;
5364	}
5365	weak_alias (__posix_memalign, posix_memalign)
5366
5367
5368	int
5369	__malloc_info (int options, FILE *fp)
5370	{
5371	/ For now, at least. /
5372	if (options != `0`)
5373	return EINVAL;
5374
5375	int n = `0`;
5376	size_t total_nblocks = `0`;
5377	size_t total_nfastblocks = `0`;
5378	size_t total_avail = `0`;
5379	size_t total_fastavail = `0`;
5380	size_t total_system = `0`;
5381	size_t total_max_system = `0`;
5382	size_t total_aspace = `0`;
5383	size_t total_aspace_mprotect = `0`;
5384
5385
5386
5387	if (__malloc_initialized < `0`)
5388	ptmalloc_init ();
5389
5390	fputs ("<malloc version=\"1\">\n", fp);
5391
5392	/ Iterate over all arenas currently in use. /
5393	mstate ar_ptr = &main_arena;
5394	do
5395	{
5396	fprintf (fp, "<heap nr=\"%d\">\n<sizes>\n", n++);
5397
5398	size_t nblocks = `0`;
5399	size_t nfastblocks = `0`;
5400	size_t avail = `0`;
5401	size_t fastavail = `0`;
5402	struct
5403	{
5404	size_t from;
5405	size_t to;
5406	size_t total;
5407	size_t count;
5408	} sizes[NFASTBINS + NBINS - `1`];
5409	#define nsizes (sizeof (sizes) / sizeof (sizes[0]))
5410
5411	__libc_lock_lock (ar_ptr->mutex);
5412
5413	for (size_t i = `0`; i < NFASTBINS; ++i)
5414	{
5415	mchunkptr p = fastbin (ar_ptr, i);
5416	if (p != NULL)
5417	{
5418	size_t nthissize = `0`;
5419	size_t thissize = chunksize (p);
5420
5421	while (p != NULL)
5422	{
5423	++nthissize;
5424	p = p->fd;
5425	}
5426
5427	fastavail += nthissize * thissize;
5428	nfastblocks += nthissize;
5429	sizes[i].from = thissize - (MALLOC_ALIGNMENT - `1`);
5430	sizes[i].to = thissize;
5431	sizes[i].count = nthissize;
5432	}
5433	else
5434	sizes[i].from = sizes[i].to = sizes[i].count = `0`;
5435
5436	sizes[i].total = sizes[i].count * sizes[i].to;
5437	}
5438
5439
5440	mbinptr bin;
5441	struct malloc_chunk *r;
5442
5443	for (size_t i = `1`; i < NBINS; ++i)
5444	{
5445	bin = bin_at (ar_ptr, i);
5446	r = bin->fd;
5447	sizes[NFASTBINS - `1` + i].from = ~((size_t) `0`);
5448	sizes[NFASTBINS - `1` + i].to = sizes[NFASTBINS - `1` + i].total
5449	= sizes[NFASTBINS - `1` + i].count = `0`;
5450
5451	if (r != NULL)
5452	while (r != bin)
5453	{
5454	size_t r_size = chunksize_nomask (r);
5455	++sizes[NFASTBINS - `1` + i].count;
5456	sizes[NFASTBINS - `1` + i].total += r_size;
5457	sizes[NFASTBINS - `1` + i].from
5458	= MIN (sizes[NFASTBINS - `1` + i].from, r_size);
5459	sizes[NFASTBINS - `1` + i].to = MAX (sizes[NFASTBINS - `1` + i].to,
5460	r_size);
5461
5462	r = r->fd;
5463	}
5464
5465	if (sizes[NFASTBINS - `1` + i].count == `0`)
5466	sizes[NFASTBINS - `1` + i].from = `0`;
5467	nblocks += sizes[NFASTBINS - `1` + i].count;
5468	avail += sizes[NFASTBINS - `1` + i].total;
5469	}
5470
5471	size_t heap_size = `0`;
5472	size_t heap_mprotect_size = `0`;
5473	size_t heap_count = `0`;
5474	if (ar_ptr != &main_arena)
5475	{
5476	/ Iterate over the arena heaps from back to front. /
5477	heap_info *heap = heap_for_ptr (top (ar_ptr));
5478	do
5479	{
5480	heap_size += heap->size;
5481	heap_mprotect_size += heap->mprotect_size;
5482	heap = heap->prev;
5483	++heap_count;
5484	}
5485	while (heap != NULL);
5486	}
5487
5488	__libc_lock_unlock (ar_ptr->mutex);
5489
5490	total_nfastblocks += nfastblocks;
5491	total_fastavail += fastavail;
5492
5493	total_nblocks += nblocks;
5494	total_avail += avail;
5495
5496	for (size_t i = `0`; i < nsizes; ++i)
5497	if (sizes[i].count != `0` && i != NFASTBINS)
5498	fprintf (fp, " \
5499	<size from=\"%zu\" to=\"%zu\" total=\"%zu\" count=\"%zu\"/>\n",
5500	sizes[i].from, sizes[i].to, sizes[i].total, sizes[i].count);
5501
5502	if (sizes[NFASTBINS].count != `0`)
5503	fprintf (fp, "\
5504	<unsorted from=\"%zu\" to=\"%zu\" total=\"%zu\" count=\"%zu\"/>\n",
5505	sizes[NFASTBINS].from, sizes[NFASTBINS].to,
5506	sizes[NFASTBINS].total, sizes[NFASTBINS].count);
5507
5508	total_system += ar_ptr->system_mem;
5509	total_max_system += ar_ptr->max_system_mem;
5510
5511	fprintf (fp,
5512	"</sizes>\n<total type=\"fast\" count=\"%zu\" size=\"%zu\"/>\n"
5513	"<total type=\"rest\" count=\"%zu\" size=\"%zu\"/>\n"
5514	"<system type=\"current\" size=\"%zu\"/>\n"
5515	"<system type=\"max\" size=\"%zu\"/>\n",
5516	nfastblocks, fastavail, nblocks, avail,
5517	ar_ptr->system_mem, ar_ptr->max_system_mem);
5518
5519	if (ar_ptr != &main_arena)
5520	{
5521	fprintf (fp,
5522	"<aspace type=\"total\" size=\"%zu\"/>\n"
5523	"<aspace type=\"mprotect\" size=\"%zu\"/>\n"
5524	"<aspace type=\"subheaps\" size=\"%zu\"/>\n",
5525	heap_size, heap_mprotect_size, heap_count);
5526	total_aspace += heap_size;
5527	total_aspace_mprotect += heap_mprotect_size;
5528	}
5529	else
5530	{
5531	fprintf (fp,
5532	"<aspace type=\"total\" size=\"%zu\"/>\n"
5533	"<aspace type=\"mprotect\" size=\"%zu\"/>\n",
5534	ar_ptr->system_mem, ar_ptr->system_mem);
5535	total_aspace += ar_ptr->system_mem;
5536	total_aspace_mprotect += ar_ptr->system_mem;
5537	}
5538
5539	fputs ("</heap>\n", fp);
5540	ar_ptr = ar_ptr->next;
5541	}
5542	while (ar_ptr != &main_arena);
5543
5544	fprintf (fp,
5545	"<total type=\"fast\" count=\"%zu\" size=\"%zu\"/>\n"
5546	"<total type=\"rest\" count=\"%zu\" size=\"%zu\"/>\n"
5547	"<total type=\"mmap\" count=\"%d\" size=\"%zu\"/>\n"
5548	"<system type=\"current\" size=\"%zu\"/>\n"
5549	"<system type=\"max\" size=\"%zu\"/>\n"
5550	"<aspace type=\"total\" size=\"%zu\"/>\n"
5551	"<aspace type=\"mprotect\" size=\"%zu\"/>\n"
5552	"</malloc>\n",
5553	total_nfastblocks, total_fastavail, total_nblocks, total_avail,
5554	mp_.n_mmaps, mp_.mmapped_mem,
5555	total_system, total_max_system,
5556	total_aspace, total_aspace_mprotect);
5557
5558	return `0`;
5559	}
5560	weak_alias (__malloc_info, malloc_info)
5561
5562
5563	strong_alias (__libc_calloc, __calloc) weak_alias (__libc_calloc, calloc)
5564	strong_alias (__libc_free, __free) strong_alias (__libc_free, free)
5565	strong_alias (__libc_malloc, __malloc) strong_alias (__libc_malloc, malloc)
5566	strong_alias (__libc_memalign, __memalign)
5567	weak_alias (__libc_memalign, memalign)
5568	strong_alias (__libc_realloc, __realloc) strong_alias (__libc_realloc, realloc)
5569	strong_alias (__libc_valloc, __valloc) weak_alias (__libc_valloc, valloc)
5570	strong_alias (__libc_pvalloc, __pvalloc) weak_alias (__libc_pvalloc, pvalloc)
5571	strong_alias (__libc_mallinfo, __mallinfo)
5572	weak_alias (__libc_mallinfo, mallinfo)
5573	strong_alias (__libc_mallopt, __mallopt) weak_alias (__libc_mallopt, mallopt)
5574
5575	weak_alias (__malloc_stats, malloc_stats)
5576	weak_alias (__malloc_usable_size, malloc_usable_size)
5577	weak_alias (__malloc_trim, malloc_trim)
5578
5579	#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_26)
5580	compat_symbol (libc, __libc_free, cfree, GLIBC_2_0);
5581	#endif
5582
5583	/ ------------------------------------------------------------*
5584	History:
5585
5586	[see ftp://g.oswego.edu/pub/misc/malloc.c for the history of dlmalloc]
5587
5588	*/
5589	/*
5590	* Local variables:
5591	* c-basic-offset: 2
5592	* End:
5593	*/
5594

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