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
40
41struct clparam
42{
43 const struct aiocb *const *list;
44 struct waitlist *waitlist;
45 struct requestlist **requestlist;
46#ifndef DONT_NEED_AIO_MISC_COND
47 pthread_cond_t *cond;
48#endif
49 int nent;
50};
51
52
53static void
54cleanup (void *arg)
55{
56#ifdef DONT_NEED_AIO_MISC_COND
57 /* Acquire the mutex. If pthread_cond_*wait is used this would
58 happen implicitly. */
59 pthread_mutex_lock (&__aio_requests_mutex);
60#endif
61
62 const struct clparam *param = (const struct clparam *) arg;
63
64 /* Now remove the entry in the waiting list for all requests
65 which didn't terminate. */
66 int cnt = param->nent;
67 while (cnt-- > 0)
68 if (param->list[cnt] != NULL
69 && param->list[cnt]->__error_code == EINPROGRESS)
70 {
71 struct waitlist **listp;
72
73 assert (param->requestlist[cnt] != NULL);
74
75 /* There is the chance that we cannot find our entry anymore. This
76 could happen if the request terminated and restarted again. */
77 listp = &param->requestlist[cnt]->waiting;
78 while (*listp != NULL && *listp != &param->waitlist[cnt])
79 listp = &(*listp)->next;
80
81 if (*listp != NULL)
82 *listp = (*listp)->next;
83 }
84
85#ifndef DONT_NEED_AIO_MISC_COND
86 /* Release the conditional variable. */
87 (void) pthread_cond_destroy (param->cond);
88#endif
89
90 /* Release the mutex. */
91 pthread_mutex_unlock (&__aio_requests_mutex);
92}
93
94#ifdef DONT_NEED_AIO_MISC_COND
95static int
96__attribute__ ((noinline))
97do_aio_misc_wait (unsigned int *cntr, const struct __timespec64 *timeout)
98{
99 int result = 0;
100
101 AIO_MISC_WAIT (result, *cntr, timeout, 1);
102
103 return result;
104}
105#endif
106
107int
108__aio_suspend_time64 (const struct aiocb *const list[], int nent,
109 const struct __timespec64 *timeout)
110{
111 if (__glibc_unlikely (nent < 0))
112 {
113 __set_errno (EINVAL);
114 return -1;
115 }
116
117 struct waitlist waitlist[nent];
118 struct requestlist *requestlist[nent];
119#ifndef DONT_NEED_AIO_MISC_COND
120 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
121#endif
122 int cnt;
123 bool any = false;
124 int result = 0;
125 unsigned int cntr = 1;
126
127 /* Request the mutex. */
128 pthread_mutex_lock (&__aio_requests_mutex);
129
130 /* There is not yet a finished request. Signal the request that
131 we are working for it. */
132 for (cnt = 0; cnt < nent; ++cnt)
133 if (list[cnt] != NULL)
134 {
135 if (list[cnt]->__error_code == EINPROGRESS)
136 {
137 requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]);
138
139 if (requestlist[cnt] != NULL)
140 {
141#ifndef DONT_NEED_AIO_MISC_COND
142 waitlist[cnt].cond = &cond;
143#endif
144 waitlist[cnt].result = NULL;
145 waitlist[cnt].next = requestlist[cnt]->waiting;
146 waitlist[cnt].counterp = &cntr;
147 waitlist[cnt].sigevp = NULL;
148 requestlist[cnt]->waiting = &waitlist[cnt];
149 any = true;
150 }
151 else
152 /* We will never suspend. */
153 break;
154 }
155 else
156 /* We will never suspend. */
157 break;
158 }
159
160 struct __timespec64 ts;
161 if (timeout != NULL)
162 {
163 __clock_gettime64 (CLOCK_MONOTONIC, &ts);
164 ts.tv_sec += timeout->tv_sec;
165 ts.tv_nsec += timeout->tv_nsec;
166 if (ts.tv_nsec >= 1000000000)
167 {
168 ts.tv_nsec -= 1000000000;
169 ts.tv_sec++;
170 }
171 }
172
173 /* Only if none of the entries is NULL or finished to be wait. */
174 if (cnt == nent && any)
175 {
176 struct clparam clparam =
177 {
178 .list = list,
179 .waitlist = waitlist,
180 .requestlist = requestlist,
181#ifndef DONT_NEED_AIO_MISC_COND
182 .cond = &cond,
183#endif
184 .nent = nent
185 };
186
187 pthread_cleanup_push (cleanup, &clparam);
188
189#ifdef DONT_NEED_AIO_MISC_COND
190 result = do_aio_misc_wait (&cntr, timeout == NULL ? NULL : &ts);
191#else
192 struct timespec ts32 = valid_timespec64_to_timespec (ts);
193 result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
194 timeout == NULL ? NULL : &ts32);
195#endif
196
197 pthread_cleanup_pop (0);
198 }
199
200 /* Now remove the entry in the waiting list for all requests
201 which didn't terminate. */
202 while (cnt-- > 0)
203 if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS)
204 {
205 struct waitlist **listp;
206
207 assert (requestlist[cnt] != NULL);
208
209 /* There is the chance that we cannot find our entry anymore. This
210 could happen if the request terminated and restarted again. */
211 listp = &requestlist[cnt]->waiting;
212 while (*listp != NULL && *listp != &waitlist[cnt])
213 listp = &(*listp)->next;
214
215 if (*listp != NULL)
216 *listp = (*listp)->next;
217 }
218
219#ifndef DONT_NEED_AIO_MISC_COND
220 /* Release the conditional variable. */
221 if (__glibc_unlikely (pthread_cond_destroy (&cond) != 0))
222 /* This must never happen. */
223 abort ();
224#endif
225
226 if (result != 0)
227 {
228#ifndef DONT_NEED_AIO_MISC_COND
229 /* An error occurred. Possibly it's ETIMEDOUT. We have to translate
230 the timeout error report of `pthread_cond_timedwait' to the
231 form expected from `aio_suspend'. */
232 if (result == ETIMEDOUT)
233 __set_errno (EAGAIN);
234 else
235#endif
236 __set_errno (result);
237
238 result = -1;
239 }
240
241 /* Release the mutex. */
242 pthread_mutex_unlock (&__aio_requests_mutex);
243
244 return result;
245}
246
247#if __TIMESIZE != 64
248librt_hidden_def (__aio_suspend_time64)
249
250int
251__aio_suspend (const struct aiocb *const list[], int nent,
252 const struct timespec *timeout)
253{
254 struct __timespec64 ts64;
255
256 if (timeout != NULL)
257 ts64 = valid_timespec_to_timespec64 (*timeout);
258
259 return __aio_suspend_time64 (list, nent, timeout != NULL ? &ts64 : NULL);
260}
261#endif
262weak_alias (__aio_suspend, aio_suspend)
263weak_alias (aio_suspend, aio_suspend64)
264