1 /* sem_wait -- wait on a semaphore. Generic futex-using version.
2 Copyright (C) 2003, 2007 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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.
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.
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 <http://www.gnu.org/licenses/>. */
22 #include <lowlevellock.h>
23 #include <internaltypes.h>
24 #include <semaphore.h>
27 #include <shlib-compat.h>
32 __sem_wait_cleanup (void *arg
)
34 struct sparc_new_sem
*isem
= (struct sparc_new_sem
*) arg
;
36 atomic_decrement (&isem
->nwaiters
);
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. */
43 __attribute__ ((noinline
))
44 do_futex_wait (struct sparc_new_sem
*isem
)
46 int err
, oldtype
= __pthread_enable_asynccancel ();
48 err
= lll_futex_wait (&isem
->value
, 0, isem
->private ^ FUTEX_PRIVATE_FLAG
);
50 __pthread_disable_asynccancel (oldtype
);
55 __new_sem_wait (sem_t
*sem
)
57 struct sparc_new_sem
*isem
= (struct sparc_new_sem
*) sem
;
60 if (atomic_decrement_if_positive (&isem
->value
) > 0)
63 atomic_increment (&isem
->nwaiters
);
65 pthread_cleanup_push (__sem_wait_cleanup
, isem
);
69 err
= do_futex_wait(isem
);
70 if (err
!= 0 && err
!= -EWOULDBLOCK
)
77 if (atomic_decrement_if_positive (&isem
->value
) > 0)
84 pthread_cleanup_pop (0);
86 atomic_decrement (&isem
->nwaiters
);
90 versioned_symbol (libpthread
, __new_sem_wait
, sem_wait
, GLIBC_2_1
);
93 #if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
95 attribute_compat_text_section
96 __old_sem_wait (sem_t
*sem
)
98 struct sparc_old_sem
*isem
= (struct sparc_old_sem
*) sem
;
103 if (atomic_decrement_if_positive (&isem
->value
) > 0)
106 /* Enable asynchronous cancellation. Required by the standard. */
107 int oldtype
= __pthread_enable_asynccancel ();
109 err
= lll_futex_wait (&isem
->value
, 0,
110 isem
->private ^ FUTEX_PRIVATE_FLAG
);
112 /* Disable asynchronous cancellation. */
113 __pthread_disable_asynccancel (oldtype
);
115 while (err
== 0 || err
== -EWOULDBLOCK
);
121 compat_symbol (libpthread
, __old_sem_wait
, sem_wait
, GLIBC_2_0
);