Update.
[glibc.git] / rt / aio_suspend.c
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1 /* Suspend until termination of a requests.
2 Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
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 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If not,
18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* We use an UGLY hack to prevent gcc from finding us cheating. The
23 implementations of aio_suspend and aio_suspend64 are identical and so
24 we want to avoid code duplication by using aliases. But gcc sees
25 the different parameter lists and prints a warning. We define here
26 a function so that aio_suspend64 has no prototype. */
27 #define aio_suspend64 XXX
28 #include <aio.h>
29 /* And undo the hack. */
30 #undef aio_suspend64
32 #include <errno.h>
33 #include <stdlib.h>
34 #include <sys/time.h>
36 #include "aio_misc.h"
39 int
40 aio_suspend (list, nent, timeout)
41 const struct aiocb *const list[];
42 int nent;
43 const struct timespec *timeout;
45 struct waitlist waitlist[nent];
46 struct requestlist *requestlist[nent];
47 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
48 int cnt;
49 int result = 0;
50 int dummy;
51 int none = 1;
53 /* Request the mutex. */
54 pthread_mutex_lock (&__aio_requests_mutex);
56 /* There is not yet a finished request. Signal the request that
57 we are working for it. */
58 for (cnt = 0; cnt < nent; ++cnt)
59 if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS)
61 requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]);
63 if (requestlist[cnt] != NULL)
65 waitlist[cnt].cond = &cond;
66 waitlist[cnt].next = requestlist[cnt]->waiting;
67 waitlist[cnt].counterp = &dummy;
68 waitlist[cnt].sigevp = NULL;
69 waitlist[cnt].caller_pid = 0; /* Not needed. */
70 requestlist[cnt]->waiting = &waitlist[cnt];
71 none = 0;
75 /* If there is a not finished request wait for it. */
76 if (!none)
78 int oldstate;
80 /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
81 points we must be careful. We added entries to the waiting lists
82 which we must remove. So defer cancelation for now. */
83 pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
85 if (timeout == NULL)
86 result = pthread_cond_wait (&cond, &__aio_requests_mutex);
87 else
89 /* We have to convert the relative timeout value into an
90 absolute time value with pthread_cond_timedwait expects. */
91 struct timeval now;
92 struct timespec abstime;
94 __gettimeofday (&now, NULL);
95 abstime.tv_nsec = timeout->tv_nsec + now.tv_usec * 1000;
96 abstime.tv_sec = timeout->tv_sec + now.tv_sec;
97 if (abstime.tv_nsec >= 1000000000)
99 abstime.tv_nsec -= 1000000000;
100 abstime.tv_sec += 1;
103 result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
104 &abstime);
107 /* Now remove the entry in the waiting list for all requests
108 which didn't terminate. */
109 for (cnt = 0; cnt < nent; ++cnt)
110 if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS
111 && requestlist[cnt] != NULL)
113 struct waitlist **listp = &requestlist[cnt]->waiting;
115 /* There is the chance that we cannot find our entry anymore.
116 This could happen if the request terminated and restarted
117 again. */
118 while (*listp != NULL && *listp != &waitlist[cnt])
119 listp = &(*listp)->next;
121 if (*listp != NULL)
122 *listp = (*listp)->next;
125 /* Now it's time to restore the cancelation state. */
126 pthread_setcancelstate (oldstate, NULL);
128 /* Release the conditional variable. */
129 if (pthread_cond_destroy (&cond) != 0)
130 /* This must never happen. */
131 abort ();
133 if (result != 0)
135 /* An error occurred. Possibly it's EINTR. We have to translate
136 the timeout error report of `pthread_cond_timedwait' to the
137 form expected from `aio_suspend'. */
138 if (result == ETIMEDOUT)
139 __set_errno (EAGAIN);
141 result = -1;
145 /* Release the mutex. */
146 pthread_mutex_unlock (&__aio_requests_mutex);
148 return result;
151 weak_alias (aio_suspend, aio_suspend64)