1/* Enqueue and list of read or write requests. Common code template.
2 Copyright (C) 1997-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20/* The following macros must be defined before including this file:
21
22 LIO_LISTIO The public symbol (lio_listio or lio_listio64).
23 AIOCB Struct tag used by LIO_LISTIO (aiocb or aiocb64).
24 LIO_LISTIO_OLD The internal symbol for the compat implementation.
25 LIO_LISTIO_NEW The internal symbol for the current implementation.
26 LIO_OPCODE_BASE Opcode shift for 64-bit version with 32-bit word size.
27
28 For __WORDSIZE == 64, LIO_LISTIO must always be lio_listio, and
29 lio_listio64 is automatically defined as well. */
30
31#include <bits/wordsize.h>
32#if __WORDSIZE == 64
33# define lio_listio64 XXX
34# include <aio.h>
35/* And undo the hack. */
36# undef lio_listio64
37#else
38# include <aio.h>
39#endif
40
41#include <assert.h>
42#include <errno.h>
43#include <stdlib.h>
44#include <unistd.h>
45#include <pthreadP.h>
46
47#include <aio_misc.h>
48
49#include <shlib-compat.h>
50
51
52/* We need this special structure to handle asynchronous I/O. */
53struct async_waitlist
54 {
55 unsigned int counter;
56 struct sigevent sigev;
57 struct waitlist list[0];
58 };
59
60
61/* The code in glibc 2.1 to glibc 2.4 issued only one event when all
62 requests submitted with lio_listio finished. The existing practice
63 is to issue events for the individual requests as well. This is
64 what the new code does. */
65#if SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
66# define LIO_MODE(mode) ((mode) & 127)
67# define NO_INDIVIDUAL_EVENT_P(mode) ((mode) & 128)
68#else
69# define LIO_MODE(mode) mode
70# define NO_INDIVIDUAL_EVENT_P(mode) 0
71#endif
72
73
74static int
75lio_listio_internal (int mode, struct AIOCB *const list[], int nent,
76 struct sigevent *sig)
77{
78 struct sigevent defsigev;
79 struct requestlist *requests[nent];
80 int cnt;
81 volatile unsigned int total = 0;
82 int result = 0;
83
84 if (sig == NULL)
85 {
86 defsigev.sigev_notify = SIGEV_NONE;
87 sig = &defsigev;
88 }
89
90 /* Request the mutex. */
91 __pthread_mutex_lock (&__aio_requests_mutex);
92
93 /* Now we can enqueue all requests. Since we already acquired the
94 mutex the enqueue function need not do this. */
95 for (cnt = 0; cnt < nent; ++cnt)
96 if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
97 {
98 if (NO_INDIVIDUAL_EVENT_P (mode))
99 list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE;
100
101 requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt],
102 (list[cnt]->aio_lio_opcode
103 | LIO_OPCODE_BASE));
104
105 if (requests[cnt] != NULL)
106 /* Successfully enqueued. */
107 ++total;
108 else
109 /* Signal that we've seen an error. `errno' and the error code
110 of the aiocb will tell more. */
111 result = -1;
112 }
113 else
114 requests[cnt] = NULL;
115
116 if (total == 0)
117 {
118 /* We don't have anything to do except signalling if we work
119 asynchronously. */
120
121 /* Release the mutex. We do this before raising a signal since the
122 signal handler might do a `siglongjmp' and then the mutex is
123 locked forever. */
124 __pthread_mutex_unlock (&__aio_requests_mutex);
125
126 if (LIO_MODE (mode) == LIO_NOWAIT)
127 __aio_notify_only (sig);
128
129 return result;
130 }
131 else if (LIO_MODE (mode) == LIO_WAIT)
132 {
133#ifndef DONT_NEED_AIO_MISC_COND
134 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
135 int oldstate;
136#endif
137 struct waitlist waitlist[nent];
138
139 total = 0;
140 for (cnt = 0; cnt < nent; ++cnt)
141 {
142 assert (requests[cnt] == NULL || list[cnt] != NULL);
143
144 if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
145 {
146#ifndef DONT_NEED_AIO_MISC_COND
147 waitlist[cnt].cond = &cond;
148#endif
149 waitlist[cnt].result = &result;
150 waitlist[cnt].next = requests[cnt]->waiting;
151 waitlist[cnt].counterp = &total;
152 waitlist[cnt].sigevp = NULL;
153 requests[cnt]->waiting = &waitlist[cnt];
154 ++total;
155 }
156 }
157
158#ifdef DONT_NEED_AIO_MISC_COND
159 AIO_MISC_WAIT (result, total, NULL, 0);
160#else
161 /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancellation
162 points we must be careful. We added entries to the waiting lists
163 which we must remove. So defer cancellation for now. */
164 pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
165
166 while (total > 0)
167 pthread_cond_wait (&cond, &__aio_requests_mutex);
168
169 /* Now it's time to restore the cancellation state. */
170 pthread_setcancelstate (oldstate, NULL);
171
172 /* Release the conditional variable. */
173 if (pthread_cond_destroy (&cond) != 0)
174 /* This must never happen. */
175 abort ();
176#endif
177
178 /* If any of the I/O requests failed, return -1 and set errno. */
179 if (result != 0)
180 {
181 __set_errno (result == EINTR ? EINTR : EIO);
182 result = -1;
183 }
184 }
185 else
186 {
187 struct async_waitlist *waitlist;
188
189 waitlist = (struct async_waitlist *)
190 malloc (sizeof (struct async_waitlist)
191 + (nent * sizeof (struct waitlist)));
192
193 if (waitlist == NULL)
194 {
195 __set_errno (EAGAIN);
196 result = -1;
197 }
198 else
199 {
200 total = 0;
201
202 for (cnt = 0; cnt < nent; ++cnt)
203 {
204 assert (requests[cnt] == NULL || list[cnt] != NULL);
205
206 if (requests[cnt] != NULL
207 && list[cnt]->aio_lio_opcode != LIO_NOP)
208 {
209#ifndef DONT_NEED_AIO_MISC_COND
210 waitlist->list[cnt].cond = NULL;
211#endif
212 waitlist->list[cnt].result = NULL;
213 waitlist->list[cnt].next = requests[cnt]->waiting;
214 waitlist->list[cnt].counterp = &waitlist->counter;
215 waitlist->list[cnt].sigevp = &waitlist->sigev;
216 requests[cnt]->waiting = &waitlist->list[cnt];
217 ++total;
218 }
219 }
220
221 waitlist->counter = total;
222 waitlist->sigev = *sig;
223 }
224 }
225
226 /* Release the mutex. */
227 __pthread_mutex_unlock (&__aio_requests_mutex);
228
229 return result;
230}
231
232
233#if OTHER_SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_4)
234int
235attribute_compat_text_section
236LIO_LISTIO_OLD (int mode, struct AIOCB *const list[], int nent,
237 struct sigevent *sig)
238{
239 /* Check arguments. */
240 if (mode != LIO_WAIT && mode != LIO_NOWAIT)
241 {
242 __set_errno (EINVAL);
243 return -1;
244 }
245
246 return lio_listio_internal (mode | LIO_NO_INDIVIDUAL_EVENT, list, nent, sig);
247}
248compat_symbol (librt, LIO_LISTIO_OLD, LIO_LISTIO, GLIBC_2_1);
249# if __WORDSIZE == 64
250compat_symbol (librt, LIO_LISTIO_OLD, lio_listio64, GLIBC_2_1);
251# endif
252#endif /* OTHER_SHLIB_COMPAT */
253
254
255int
256LIO_LISTIO_NEW (int mode, struct AIOCB *const list[], int nent,
257 struct sigevent *sig)
258{
259 /* Check arguments. */
260 if (mode != LIO_WAIT && mode != LIO_NOWAIT)
261 {
262 __set_errno (EINVAL);
263 return -1;
264 }
265
266 return lio_listio_internal (mode, list, nent, sig);
267}
268
269#if PTHREAD_IN_LIBC
270versioned_symbol (libc, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_34);
271# if __WORDSIZE == 64
272versioned_symbol (libc, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_34);
273# endif
274# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_4, GLIBC_2_34)
275compat_symbol (librt, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_4);
276# if __WORDSIZE == 64
277compat_symbol (librt, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_4);
278# endif
279# endif /* OTHER_SHLIB_COMPAT */
280#else /* !PTHREAD_IN_LIBC */
281versioned_symbol (librt, LIO_LISTIO_NEW, LIO_LISTIO, GLIBC_2_4);
282# if __WORDSIZE == 64
283versioned_symbol (librt, LIO_LISTIO_NEW, lio_listio64, GLIBC_2_4);
284# endif
285#endif /* !PTHREAD_IN_LIBC */
286