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cbdee279 UD |
1 | /* Suspend until termination of a requests. |
2 | Copyright (C) 1997 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 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. | |
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 | Library General Public License for more details. | |
15 | ||
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. */ | |
20 | ||
21 | ||
22 | /* We use an UGLY hack to prevent gcc from finding us cheating. The | |
23 | implementation 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 | |
31 | ||
32 | #include <errno.h> | |
33 | ||
34 | #include "aio_misc.h" | |
35 | ||
36 | ||
37 | int | |
38 | aio_suspend (list, nent, timeout) | |
39 | const struct aiocb *const list[]; | |
40 | int nent; | |
41 | const struct timespec *timeout; | |
42 | { | |
d71b808a UD |
43 | pthread_cond_t cond; |
44 | struct waitlist waitlist[nent]; | |
45 | struct requestlist *requestlist[nent]; | |
cbdee279 | 46 | int cnt; |
d71b808a UD |
47 | int result = 0; |
48 | ||
49 | /* Request the mutex. */ | |
50 | pthread_mutex_lock (&__aio_requests_mutex); | |
cbdee279 UD |
51 | |
52 | /* First look whether there is already a terminated request. */ | |
53 | for (cnt = 0; cnt < nent; ++cnt) | |
54 | if (list[cnt] != NULL && list[cnt]->__error_code != EINPROGRESS) | |
d71b808a UD |
55 | break; |
56 | ||
57 | if (cnt == nent) | |
58 | { | |
59 | int oldstate; | |
60 | ||
61 | /* There is not yet a finished request. Signal the request that | |
62 | we are working for it. */ | |
63 | for (cnt = 0; cnt < nent; ++cnt) | |
64 | if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS) | |
65 | { | |
66 | requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]); | |
67 | ||
68 | if (requestlist[cnt] != NULL) | |
69 | { | |
70 | waitlist[cnt].cond = &cond; | |
71 | waitlist[cnt].next = requestlist[cnt]->waiting; | |
72 | waitlist[cnt].counterp = NULL; | |
73 | waitlist[cnt].sigevp = NULL; | |
74 | requestlist[cnt]->waiting = &waitlist[cnt]; | |
75 | } | |
76 | } | |
77 | ||
78 | /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation | |
79 | points we must be careful. We added entries to the waiting lists | |
80 | which we must remove. So defer cancelation for now. */ | |
81 | pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate); | |
82 | ||
83 | if (timeout == NULL) | |
84 | result = pthread_cond_wait (&cond, &__aio_requests_mutex); | |
85 | else | |
86 | result = pthread_cond_timedwait (&cond, &__aio_requests_mutex, | |
87 | timeout); | |
88 | ||
89 | /* Now remove the entry in the waiting list for all requests | |
90 | which didn't terminate */ | |
91 | for (cnt = 0; cnt < nent; ++cnt) | |
92 | if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS | |
93 | && requestlist[cnt] != NULL) | |
94 | { | |
95 | struct waitlist **listp = &requestlist[cnt]->waiting; | |
96 | ||
97 | /* There is the chance that we cannot find our entry anymore. | |
98 | This could happen if the request terminated and restarted | |
99 | again. */ | |
100 | while (*listp != NULL && *listp != &waitlist[cnt]) | |
101 | listp = &(*listp)->next; | |
102 | ||
103 | if (*listp != NULL) | |
104 | *listp = (*listp)->next; | |
105 | } | |
106 | ||
107 | /* Now it's time to restore the cancelation state. */ | |
108 | pthread_setcancelstate (oldstate, NULL); | |
109 | ||
110 | if (result != 0) | |
111 | { | |
112 | /* An error occurred. Possibly it's EINTR. We have to translate | |
113 | the timeout error report of `pthread_cond_timedwait' to the | |
114 | form expected from `aio_suspend'. */ | |
115 | if (result == ETIMEDOUT) | |
116 | __set_errno (EAGAIN); | |
117 | ||
118 | result = -1; | |
119 | } | |
120 | } | |
cbdee279 | 121 | |
d71b808a UD |
122 | /* Release the mutex. */ |
123 | pthread_mutex_unlock (&__aio_requests_mutex); | |
cbdee279 | 124 | |
d71b808a | 125 | return result; |
cbdee279 UD |
126 | } |
127 | ||
128 | weak_alias (aio_suspend, aio_suspend64) |