1/* Suspend until termination of a requests.
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
21/* We use an UGLY hack to prevent gcc from finding us cheating. The
22 implementations of aio_suspend and aio_suspend64 are identical and so
23 we want to avoid code duplication by using aliases. But gcc sees
24 the different parameter lists and prints a warning. We define here
25 a function so that aio_suspend64 has no prototype. */
26#define aio_suspend64 XXX
27#include <aio.h>
28/* And undo the hack. */
29#undef aio_suspend64
30
31#include <assert.h>
32#include <errno.h>
33#include <stdbool.h>
34#include <stdlib.h>
35#include <sys/time.h>
36
37#include <libc-lock.h>
38#include <aio_misc.h>
39#include <pthreadP.h>
40#include <shlib-compat.h>
41
42
43struct clparam
44{
45 const struct aiocb *const *list;
46 struct waitlist *waitlist;
47 struct requestlist **requestlist;
48#ifndef DONT_NEED_AIO_MISC_COND
49 pthread_cond_t *cond;
50#endif
51 int nent;
52};
53
54
55static void
56cleanup (void *arg)
57{
58#ifdef DONT_NEED_AIO_MISC_COND
59 /* Acquire the mutex. If pthread_cond_*wait is used this would
60 happen implicitly. */
61 __pthread_mutex_lock (&__aio_requests_mutex);
62#endif
63
64 const struct clparam *param = (const struct clparam *) arg;
65
66 /* Now remove the entry in the waiting list for all requests
67 which didn't terminate. */
68 int cnt = param->nent;
69 while (cnt-- > 0)
70 if (param->list[cnt] != NULL
71 && param->list[cnt]->__error_code == EINPROGRESS)
72 {
73 struct waitlist **listp;
74
75 assert (param->requestlist[cnt] != NULL);
76
77 /* There is the chance that we cannot find our entry anymore. This
78 could happen if the request terminated and restarted again. */
79 listp = &param->requestlist[cnt]->waiting;
80 while (*listp != NULL && *listp != &param->waitlist[cnt])
81 listp = &(*listp)->next;
82
83 if (*listp != NULL)
84 *listp = (*listp)->next;
85 }
86
87#ifndef DONT_NEED_AIO_MISC_COND
88 /* Release the conditional variable. */
89 (void) pthread_cond_destroy (param->cond);
90#endif
91
92 /* Release the mutex. */
93 __pthread_mutex_unlock (&__aio_requests_mutex);
94}
95
96#ifdef DONT_NEED_AIO_MISC_COND
97static int
98__attribute__ ((noinline))
99do_aio_misc_wait (unsigned int *cntr, const struct __timespec64 *timeout)
100{
101 int result = 0;
102
103 AIO_MISC_WAIT (result, *cntr, timeout, 1);
104
105 return result;
106}
107#endif
108
109int
110___aio_suspend_time64 (const struct aiocb *const list[], int nent,
111 const struct __timespec64 *timeout)
112{
113 if (__glibc_unlikely (nent < 0))
114 {
115 __set_errno (EINVAL);
116 return -1;
117 }
118
119 struct waitlist waitlist[nent];
120 struct requestlist *requestlist[nent];
121#ifndef DONT_NEED_AIO_MISC_COND
122 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
123#endif
124 int cnt;
125 bool any = false;
126 int result = 0;
127 unsigned int cntr = 1;
128
129 /* Request the mutex. */
130 __pthread_mutex_lock (&__aio_requests_mutex);
131
132 /* There is not yet a finished request. Signal the request that
133 we are working for it. */
134 for (cnt = 0; cnt < nent; ++cnt)
135 if (list[cnt] != NULL)
136 {
137 if (list[cnt]->__error_code == EINPROGRESS)
138 {
139 requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]);
140
141 if (requestlist[cnt] != NULL)
142 {
143#ifndef DONT_NEED_AIO_MISC_COND
144 waitlist[cnt].cond = &cond;
145#endif
146 waitlist[cnt].result = NULL;
147 waitlist[cnt].next = requestlist[cnt]->waiting;
148 waitlist[cnt].counterp = &cntr;
149 waitlist[cnt].sigevp = NULL;
150 requestlist[cnt]->waiting = &waitlist[cnt];
151 any = true;
152 }
153 else
154 /* We will never suspend. */
155 break;
156 }
157 else
158 /* We will never suspend. */
159 break;
160 }
161
162 struct __timespec64 ts;
163 if (timeout != NULL)
164 {
165 __clock_gettime64 (CLOCK_MONOTONIC, &ts);
166 ts.tv_sec += timeout->tv_sec;
167 ts.tv_nsec += timeout->tv_nsec;
168 if (ts.tv_nsec >= 1000000000)
169 {
170 ts.tv_nsec -= 1000000000;
171 ts.tv_sec++;
172 }
173 }
174
175 /* Only if none of the entries is NULL or finished to be wait. */
176 if (cnt == nent && any)
177 {
178 struct clparam clparam =
179 {
180 .list = list,
181 .waitlist = waitlist,
182 .requestlist = requestlist,
183#ifndef DONT_NEED_AIO_MISC_COND
184 .cond = &cond,
185#endif
186 .nent = nent
187 };
188
189#if PTHREAD_IN_LIBC
190 __libc_cleanup_region_start (1, cleanup, &clparam);
191#else
192 __pthread_cleanup_push (cleanup, &clparam);
193#endif
194
195#ifdef DONT_NEED_AIO_MISC_COND
196 result = do_aio_misc_wait (&cntr, timeout == NULL ? NULL : &ts);
197#else
198 struct timespec ts32 = valid_timespec64_to_timespec (ts);
199 result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
200 timeout == NULL ? NULL : &ts32);
201#endif
202
203#if PTHREAD_IN_LIBC
204 __libc_cleanup_region_end (0);
205#else
206 pthread_cleanup_pop (0);
207#endif
208 }
209
210 /* Now remove the entry in the waiting list for all requests
211 which didn't terminate. */
212 while (cnt-- > 0)
213 if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS)
214 {
215 struct waitlist **listp;
216
217 assert (requestlist[cnt] != NULL);
218
219 /* There is the chance that we cannot find our entry anymore. This
220 could happen if the request terminated and restarted again. */
221 listp = &requestlist[cnt]->waiting;
222 while (*listp != NULL && *listp != &waitlist[cnt])
223 listp = &(*listp)->next;
224
225 if (*listp != NULL)
226 *listp = (*listp)->next;
227 }
228
229#ifndef DONT_NEED_AIO_MISC_COND
230 /* Release the conditional variable. */
231 if (__glibc_unlikely (pthread_cond_destroy (&cond) != 0))
232 /* This must never happen. */
233 abort ();
234#endif
235
236 if (result != 0)
237 {
238#ifndef DONT_NEED_AIO_MISC_COND
239 /* An error occurred. Possibly it's ETIMEDOUT. We have to translate
240 the timeout error report of `pthread_cond_timedwait' to the
241 form expected from `aio_suspend'. */
242 if (result == ETIMEDOUT)
243 __set_errno (EAGAIN);
244 else
245#endif
246 __set_errno (result);
247
248 result = -1;
249 }
250
251 /* Release the mutex. */
252 __pthread_mutex_unlock (&__aio_requests_mutex);
253
254 return result;
255}
256
257#if __TIMESIZE == 64
258strong_alias (___aio_suspend_time64, __aio_suspend)
259#else /* __TIMESIZE != 64 */
260# if PTHREAD_IN_LIBC
261libc_hidden_ver (___aio_suspend_time64, __aio_suspend_time64)
262/* The conditional is slightly wrong: PTHREAD_IN_LIBC is a stand-in
263 for whether time64 support is needed. */
264versioned_symbol (libc, ___aio_suspend_time64, __aio_suspend_time64, GLIBC_2_34);
265# else
266librt_hidden_ver (___aio_suspend_time64, __aio_suspend_time64)
267# endif
268
269int
270__aio_suspend (const struct aiocb *const list[], int nent,
271 const struct timespec *timeout)
272{
273 struct __timespec64 ts64;
274
275 if (timeout != NULL)
276 ts64 = valid_timespec_to_timespec64 (*timeout);
277
278 return __aio_suspend_time64 (list, nent, timeout != NULL ? &ts64 : NULL);
279}
280#endif /* __TIMESPEC64 != 64 */
281
282#if PTHREAD_IN_LIBC
283versioned_symbol (libc, __aio_suspend, aio_suspend, GLIBC_2_34);
284versioned_symbol (libc, __aio_suspend, aio_suspend64, GLIBC_2_34);
285# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_1, GLIBC_2_34)
286compat_symbol (librt, __aio_suspend, aio_suspend, GLIBC_2_1);
287compat_symbol (librt, __aio_suspend, aio_suspend64, GLIBC_2_1);
288# endif
289#else /* !PTHREAD_IN_LIBC */
290weak_alias (__aio_suspend, aio_suspend)
291weak_alias (__aio_suspend, aio_suspend64)
292#endif /* !PTHREAD_IN_LIBC */
293