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e4720b0e | 1 | /* sem_wait -- wait on a semaphore. Generic futex-using version. |
d4697bc9 | 2 | Copyright (C) 2003-2014 Free Software Foundation, Inc. |
e4720b0e JJ |
3 | This file is part of the GNU C Library. |
4 | Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. | |
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 | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
e4720b0e JJ |
19 | |
20 | #include <errno.h> | |
21 | #include <sysdep.h> | |
22 | #include <lowlevellock.h> | |
23 | #include <internaltypes.h> | |
24 | #include <semaphore.h> | |
25 | ||
26 | #include <pthreadP.h> | |
27 | #include <shlib-compat.h> | |
28 | ||
29 | ||
30 | void | |
31 | attribute_hidden | |
32 | __sem_wait_cleanup (void *arg) | |
33 | { | |
34 | struct sparc_new_sem *isem = (struct sparc_new_sem *) arg; | |
35 | ||
36 | atomic_decrement (&isem->nwaiters); | |
37 | } | |
38 | ||
39c4451c DM |
39 | /* This is in a seperate function in order to make sure gcc |
40 | puts the call site into an exception region, and thus the | |
41 | cleanups get properly run. */ | |
42 | static int | |
43 | __attribute__ ((noinline)) | |
44 | do_futex_wait (struct sparc_new_sem *isem) | |
45 | { | |
46 | int err, oldtype = __pthread_enable_asynccancel (); | |
47 | ||
48 | err = lll_futex_wait (&isem->value, 0, isem->private ^ FUTEX_PRIVATE_FLAG); | |
49 | ||
50 | __pthread_disable_asynccancel (oldtype); | |
51 | return err; | |
52 | } | |
e4720b0e JJ |
53 | |
54 | int | |
55 | __new_sem_wait (sem_t *sem) | |
56 | { | |
57 | struct sparc_new_sem *isem = (struct sparc_new_sem *) sem; | |
58 | int err; | |
59 | ||
60 | if (atomic_decrement_if_positive (&isem->value) > 0) | |
61 | return 0; | |
62 | ||
63 | atomic_increment (&isem->nwaiters); | |
64 | ||
65 | pthread_cleanup_push (__sem_wait_cleanup, isem); | |
66 | ||
67 | while (1) | |
68 | { | |
39c4451c | 69 | err = do_futex_wait(isem); |
e4720b0e JJ |
70 | if (err != 0 && err != -EWOULDBLOCK) |
71 | { | |
72 | __set_errno (-err); | |
73 | err = -1; | |
74 | break; | |
75 | } | |
76 | ||
77 | if (atomic_decrement_if_positive (&isem->value) > 0) | |
78 | { | |
79 | err = 0; | |
80 | break; | |
81 | } | |
82 | } | |
83 | ||
84 | pthread_cleanup_pop (0); | |
85 | ||
86 | atomic_decrement (&isem->nwaiters); | |
87 | ||
88 | return err; | |
89 | } | |
90 | versioned_symbol (libpthread, __new_sem_wait, sem_wait, GLIBC_2_1); | |
91 | ||
92 | ||
93 | #if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1) | |
94 | int | |
95 | attribute_compat_text_section | |
96 | __old_sem_wait (sem_t *sem) | |
97 | { | |
98 | struct sparc_old_sem *isem = (struct sparc_old_sem *) sem; | |
99 | int err; | |
100 | ||
101 | do | |
102 | { | |
103 | if (atomic_decrement_if_positive (&isem->value) > 0) | |
104 | return 0; | |
105 | ||
106 | /* Enable asynchronous cancellation. Required by the standard. */ | |
107 | int oldtype = __pthread_enable_asynccancel (); | |
108 | ||
109 | err = lll_futex_wait (&isem->value, 0, | |
110 | isem->private ^ FUTEX_PRIVATE_FLAG); | |
111 | ||
112 | /* Disable asynchronous cancellation. */ | |
113 | __pthread_disable_asynccancel (oldtype); | |
114 | } | |
115 | while (err == 0 || err == -EWOULDBLOCK); | |
116 | ||
117 | __set_errno (-err); | |
118 | return -1; | |
119 | } | |
120 | ||
121 | compat_symbol (libpthread, __old_sem_wait, sem_wait, GLIBC_2_0); | |
122 | #endif |