1 /* Suspend until termination of a requests.
2 Copyright (C) 1997-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19
20 /* We use an UGLY hack to prevent gcc from finding us cheating. The
21 implementations of aio_suspend and aio_suspend64 are identical and so
22 we want to avoid code duplication by using aliases. But gcc sees
23 the different parameter lists and prints a warning. We define here
24 a function so that aio_suspend64 has no prototype. */
25 #define aio_suspend64 XXX
26 #include <aio.h>
27 /* And undo the hack. */
28 #undef aio_suspend64
29
30 #include <assert.h>
31 #include <errno.h>
32 #include <stdbool.h>
33 #include <stdlib.h>
34 #include <sys/time.h>
35
36 #include <libc-lock.h>
37 #include <aio_misc.h>
38 #include <pthreadP.h>
39 #include <shlib-compat.h>
40
41
42 struct clparam
43 {
44 const struct aiocb *const *list;
45 struct waitlist *waitlist;
46 struct requestlist **requestlist;
47 #ifndef DONT_NEED_AIO_MISC_COND
48 pthread_cond_t *cond;
49 #endif
50 int nent;
51 };
52
53
54 static void
55 cleanup (void *arg)
56 {
57 #ifdef DONT_NEED_AIO_MISC_COND
58 /* Acquire the mutex. If pthread_cond_*wait is used this would
59 happen implicitly. */
60 __pthread_mutex_lock (&__aio_requests_mutex);
61 #endif
62
63 const struct clparam *param = (const struct clparam *) arg;
64
65 /* Now remove the entry in the waiting list for all requests
66 which didn't terminate. */
67 int cnt = param->nent;
68 while (cnt-- > 0)
69 if (param->list[cnt] != NULL
70 && param->list[cnt]->__error_code == EINPROGRESS)
71 {
72 struct waitlist **listp;
73
74 assert (param->requestlist[cnt] != NULL);
75
76 /* There is the chance that we cannot find our entry anymore. This
77 could happen if the request terminated and restarted again. */
78 listp = ¶m->requestlist[cnt]->waiting;
79 while (*listp != NULL && *listp != ¶m->waitlist[cnt])
80 listp = &(*listp)->next;
81
82 if (*listp != NULL)
83 *listp = (*listp)->next;
84 }
85
86 #ifndef DONT_NEED_AIO_MISC_COND
87 /* Release the conditional variable. */
88 (void) pthread_cond_destroy (param->cond);
89 #endif
90
91 /* Release the mutex. */
92 __pthread_mutex_unlock (&__aio_requests_mutex);
93 }
94
95 #ifdef DONT_NEED_AIO_MISC_COND
96 static int
97 __attribute__ ((noinline))
98 do_aio_misc_wait (unsigned int *cntr, const struct __timespec64 *timeout)
99 {
100 int result = 0;
101
102 AIO_MISC_WAIT (result, *cntr, timeout, 1);
103
104 return result;
105 }
106 #endif
107
108 int
109 ___aio_suspend_time64 (const struct aiocb *const list[], int nent,
110 const struct __timespec64 *timeout)
111 {
112 if (__glibc_unlikely (nent < 0))
113 {
114 __set_errno (EINVAL);
115 return -1;
116 }
117
118 struct waitlist waitlist[nent];
119 struct requestlist *requestlist[nent];
120 #ifndef DONT_NEED_AIO_MISC_COND
121 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
122 #endif
123 int cnt;
124 bool any = false;
125 int result = 0;
126 unsigned int cntr = 1;
127
128 /* Request the mutex. */
129 __pthread_mutex_lock (&__aio_requests_mutex);
130
131 /* There is not yet a finished request. Signal the request that
132 we are working for it. */
133 for (cnt = 0; cnt < nent; ++cnt)
134 if (list[cnt] != NULL)
135 {
136 if (list[cnt]->__error_code == EINPROGRESS)
137 {
138 requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]);
139
140 if (requestlist[cnt] != NULL)
141 {
142 #ifndef DONT_NEED_AIO_MISC_COND
143 waitlist[cnt].cond = &cond;
144 #endif
145 waitlist[cnt].result = NULL;
146 waitlist[cnt].next = requestlist[cnt]->waiting;
147 waitlist[cnt].counterp = &cntr;
148 waitlist[cnt].sigevp = NULL;
149 requestlist[cnt]->waiting = &waitlist[cnt];
150 any = true;
151 }
152 else
153 /* We will never suspend. */
154 break;
155 }
156 else
157 /* We will never suspend. */
158 break;
159 }
160
161 struct __timespec64 ts;
162 if (timeout != NULL)
163 {
164 __clock_gettime64 (CLOCK_MONOTONIC, &ts);
165 ts.tv_sec += timeout->tv_sec;
166 ts.tv_nsec += timeout->tv_nsec;
167 if (ts.tv_nsec >= 1000000000)
168 {
169 ts.tv_nsec -= 1000000000;
170 ts.tv_sec++;
171 }
172 }
173
174 /* Only if none of the entries is NULL or finished to be wait. */
175 if (cnt == nent && any)
176 {
177 struct clparam clparam =
178 {
179 .list = list,
180 .waitlist = waitlist,
181 .requestlist = requestlist,
182 #ifndef DONT_NEED_AIO_MISC_COND
183 .cond = &cond,
184 #endif
185 .nent = nent
186 };
187
188 #if PTHREAD_IN_LIBC
189 __libc_cleanup_region_start (1, cleanup, &clparam);
190 #else
191 __pthread_cleanup_push (cleanup, &clparam);
192 #endif
193
194 #ifdef DONT_NEED_AIO_MISC_COND
195 result = do_aio_misc_wait (&cntr, timeout == NULL ? NULL : &ts);
196 #else
197 struct timespec ts32 = valid_timespec64_to_timespec (ts);
198 result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
199 timeout == NULL ? NULL : &ts32);
200 #endif
201
202 #if PTHREAD_IN_LIBC
203 __libc_cleanup_region_end (0);
204 #else
205 pthread_cleanup_pop (0);
206 #endif
207 }
208
209 /* Now remove the entry in the waiting list for all requests
210 which didn't terminate. */
211 while (cnt-- > 0)
212 if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS)
213 {
214 struct waitlist **listp;
215
216 assert (requestlist[cnt] != NULL);
217
218 /* There is the chance that we cannot find our entry anymore. This
219 could happen if the request terminated and restarted again. */
220 listp = &requestlist[cnt]->waiting;
221 while (*listp != NULL && *listp != &waitlist[cnt])
222 listp = &(*listp)->next;
223
224 if (*listp != NULL)
225 *listp = (*listp)->next;
226 }
227
228 #ifndef DONT_NEED_AIO_MISC_COND
229 /* Release the conditional variable. */
230 if (__glibc_unlikely (pthread_cond_destroy (&cond) != 0))
231 /* This must never happen. */
232 abort ();
233 #endif
234
235 if (result != 0)
236 {
237 #ifndef DONT_NEED_AIO_MISC_COND
238 /* An error occurred. Possibly it's ETIMEDOUT. We have to translate
239 the timeout error report of `pthread_cond_timedwait' to the
240 form expected from `aio_suspend'. */
241 if (result == ETIMEDOUT)
242 __set_errno (EAGAIN);
243 else
244 #endif
245 __set_errno (result);
246
247 result = -1;
248 }
249
250 /* Release the mutex. */
251 __pthread_mutex_unlock (&__aio_requests_mutex);
252
253 return result;
254 }
255
256 #if __TIMESIZE == 64
257 strong_alias (___aio_suspend_time64, __aio_suspend)
258 #else /* __TIMESIZE != 64 */
259 # if PTHREAD_IN_LIBC
260 libc_hidden_ver (___aio_suspend_time64, __aio_suspend_time64)
261 /* The conditional is slightly wrong: PTHREAD_IN_LIBC is a stand-in
262 for whether time64 support is needed. */
263 versioned_symbol (libc, ___aio_suspend_time64, __aio_suspend_time64, GLIBC_2_34);
264 # else
265 librt_hidden_ver (___aio_suspend_time64, __aio_suspend_time64)
266 # endif
267
268 int
269 __aio_suspend (const struct aiocb *const list[], int nent,
270 const struct timespec *timeout)
271 {
272 struct __timespec64 ts64;
273
274 if (timeout != NULL)
275 ts64 = valid_timespec_to_timespec64 (*timeout);
276
277 return __aio_suspend_time64 (list, nent, timeout != NULL ? &ts64 : NULL);
278 }
279 #endif /* __TIMESPEC64 != 64 */
280
281 #if PTHREAD_IN_LIBC
282 versioned_symbol (libc, __aio_suspend, aio_suspend, GLIBC_2_34);
283 versioned_symbol (libc, __aio_suspend, aio_suspend64, GLIBC_2_34);
284 # if OTHER_SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_34)
285 compat_symbol (librt, __aio_suspend, aio_suspend, GLIBC_2_1);
286 compat_symbol (librt, __aio_suspend, aio_suspend64, GLIBC_2_1);
287 # endif
288 #else /* !PTHREAD_IN_LIBC */
289 weak_alias (__aio_suspend, aio_suspend)
290 weak_alias (__aio_suspend, aio_suspend64)
291 #endif /* !PTHREAD_IN_LIBC */