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Use a static lock to ake sure pthread_cond_* functions called

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from multiple threads don't initialze the same condition variable
more than once.

Explicitly compare cond pointers with PTHREAD_COND_INITIALIZER instead
of NULL. Just because it happens to be defined as NULL is no reason
to encourage the idea that people can call those functions with
NULL pointers to a condition variable.

Approved by:	re/jhb
This commit is contained in:
Mike Makonnen 2003-05-29 20:54:00 +00:00
parent 0e335eaeb5
commit 41f2bd859f
1 changed files with 20 additions and 2 deletions
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22
lib/libthr/thread/thr_cond.c
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@ -37,9 +37,16 @@
#include <pthread.h>
#include "thr_private.h"
/*
* Proctect two different threads calling a pthread_cond_* function
* from accidentally initializing the condition variable twice.
*/
static spinlock_t static_cond_lock = _SPINLOCK_INITIALIZER;
/*
* Prototypes
*/
static inline int cond_init(pthread_cond_t *);
static pthread_t cond_queue_deq(pthread_cond_t);
static void cond_queue_remove(pthread_cond_t, pthread_t);
static void cond_queue_enq(pthread_cond_t, pthread_t);
@ -202,7 +209,7 @@ cond_wait_common(pthread_cond_t * cond, pthread_mutex_t * mutex,
* If the condition variable is statically initialized, perform dynamic
* initialization.
*/
if (*cond == NULL && (rval = pthread_cond_init(cond, NULL)) != 0)
if (*cond == PTHREAD_COND_INITIALIZER && (rval = cond_init(cond)) != 0)
return (rval);
@ -363,7 +370,7 @@ cond_signal(pthread_cond_t * cond, int broadcast)
* If the condition variable is statically initialized, perform dynamic
* initialization.
*/
if (*cond == NULL && (rval = pthread_cond_init(cond, NULL)) != 0)
if (*cond == PTHREAD_COND_INITIALIZER && (rval = cond_init(cond)) != 0)
return (rval);
COND_LOCK(*cond);
@ -518,3 +525,14 @@ cond_queue_enq(pthread_cond_t cond, pthread_t pthread)
pthread->flags |= PTHREAD_FLAGS_IN_CONDQ;
pthread->data.cond = cond;
}
static inline int
cond_init(pthread_cond_t *cond)
{
_SPINLOCK(&static_cond_lock);
if (*cond == PTHREAD_COND_INITIALIZER)
return (_pthread_cond_init(cond, NULL));
_SPINUNLOCK(&static_cond_lock);
return (0);
}