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authorSamuel Thibault <sthibault@debian.org>2009-08-20 09:54:45 +0200
committerJulien Danjou <julien@danjou.info>2009-08-20 09:54:45 +0200
commit3d8dfe9a9ad0a22bdcec555bd3d0d9b5950a6dab (patch)
treed241894d05e20db502e7901e7c9f0d31bca35903
parentef2431f5bdef1da9f2f7701232def164910b191b (diff)
Provide sem_* functions
Some applications, instead of using pthread_mutex_t, use anonymous semaphores (sem_init) for locking. Signed-off-by: Julien Danjou <julien@danjou.info>
-rw-r--r--configure.ac2
-rw-r--r--stubs.c103
2 files changed, 104 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac
index b7f0698..ffccea9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -31,7 +31,7 @@ fi
PKG_CONFIG_LIBS=
-AC_CHECK_FUNCS([pthread_self pthread_mutex_init pthread_mutex_destroy pthread_mutex_lock pthread_mutex_unlock pthread_cond_init pthread_cond_destroy pthread_cond_wait pthread_cond_signal pthread_cond_broadcast pthread_equal],
+AC_CHECK_FUNCS([pthread_self pthread_mutex_init pthread_mutex_destroy pthread_mutex_lock pthread_mutex_unlock pthread_cond_init pthread_cond_destroy pthread_cond_wait pthread_cond_signal pthread_cond_broadcast pthread_equal sem_init sem_destroy sem_wait sem_trywait],
[], [PKG_CONFIG_LIBS='-L${libdir} -lpthread-stubs'])
AC_SUBST([PKG_CONFIG_LIBS])
AM_CONDITIONAL(BUILD_LIB, test "x$PKG_CONFIG_LIBS" != x)
diff --git a/stubs.c b/stubs.c
index d267fa6..c553e4d 100644
--- a/stubs.c
+++ b/stubs.c
@@ -25,6 +25,8 @@
*/
#include <pthread.h>
+#include <errno.h>
+#include <semaphore.h>
#include "config.h"
#ifndef HAVE_PTHREAD_SELF
@@ -126,6 +128,51 @@ int pthread_equal() __attribute__ ((weak, alias ("__pthread_equal_stub")));
# endif
#endif
+#ifndef HAVE_SEM_INIT
+#define NEED_SEM_INIT_STUB
+# ifdef SUPPORT_ATTRIBUTE_ALIAS
+int sem_init() __attribute__ ((weak, alias ("__sem_init_stub")));
+# else
+# pragma weak sem_init = __sem_init_stub
+# endif
+#endif
+
+#ifndef HAVE_SEM_DESTROY
+#define NEED_ZERO_STUB
+# ifdef SUPPORT_ATTRIBUTE_ALIAS
+int sem_destroy() __attribute__ ((weak, alias ("__pthread_zero_stub")));
+# else
+# pragma weak sem_destroy = __sem_destroy_stub
+# endif
+#endif
+
+#ifndef HAVE_SEM_WAIT
+#define NEED_SEM_WAIT_STUB
+# ifdef SUPPORT_ATTRIBUTE_ALIAS
+int sem_wait() __attribute__ ((weak, alias ("__sem_wait_stub")));
+# else
+# pragma weak sem_wait = __sem_wait_stub
+# endif
+#endif
+
+#ifndef HAVE_SEM_TRYWAIT
+#define NEED_SEM_TRYWAIT_STUB
+# ifdef SUPPORT_ATTRIBUTE_ALIAS
+int sem_trywait() __attribute__ ((weak, alias ("__sem_trywait_stub")));
+# else
+# pragma weak sem_trywait = __sem_trywait_stub
+# endif
+#endif
+
+#ifndef HAVE_SEM_POST
+#define NEED_SEM_POST_STUB
+# ifdef SUPPORT_ATTRIBUTE_ALIAS
+int sem_post() __attribute__ ((weak, alias ("__sem_post_stub")));
+# else
+# pragma weak sem_post = __sem_post_stub
+# endif
+#endif
+
#ifdef NEED_ZERO_STUB
static int __pthread_zero_stub()
{
@@ -139,3 +186,59 @@ static int __pthread_equal_stub(pthread_t t1, pthread_t t2)
return (t1 == t2);
}
#endif
+
+#ifdef NEED_SEM_INIT_STUB
+static int __sem_init_stub(sem_t *_sem, int pshared, unsigned int value)
+{
+ unsigned int *sem = (unsigned int *) _sem;
+ if (pshared) {
+ errno = ENOSYS;
+ return -1;
+ }
+
+ if (sizeof(sem_t) < sizeof(unsigned int)) {
+ errno = ENOSYS;
+ return -1;
+ }
+
+ *sem = value;
+ return 0;
+}
+#endif
+
+#ifdef NEED_SEM_WAIT_STUB
+static int __sem_wait_stub(sem_t *_sem)
+{
+ unsigned int *sem = (unsigned int *) _sem;
+ if (!*sem) {
+ /* Not available, simulate a blocking sem_wait */
+ pause();
+ errno = EINTR;
+ return -1;
+ }
+ *sem--;
+ return 0;
+}
+#endif
+
+#ifdef NEED_SEM_TRYWAIT_STUB
+static int __sem_trywait_stub(sem_t *_sem)
+{
+ unsigned int *sem = (unsigned int *) _sem;
+ if (!*sem) {
+ errno = EAGAIN;
+ return -1;
+ }
+ *sem--;
+ return 0;
+}
+#endif
+
+#ifdef NEED_SEM_POST_STUB
+static int __sem_post_stub(sem_t *_sem)
+{
+ unsigned int *sem = (unsigned int *) _sem;
+ *sem++;
+ return 0;
+}
+#endif