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-rw-r--r--src/lib/shm_ap_rbuff.c32
1 files changed, 23 insertions, 9 deletions
diff --git a/src/lib/shm_ap_rbuff.c b/src/lib/shm_ap_rbuff.c
index 1cfafeda..63aa8813 100644
--- a/src/lib/shm_ap_rbuff.c
+++ b/src/lib/shm_ap_rbuff.c
@@ -36,7 +36,8 @@
#include <errno.h>
#define SHM_RBUFF_FILE_SIZE (SHM_RBUFF_SIZE * sizeof(struct rb_entry) \
- + 2 * sizeof(size_t) + sizeof(pthread_mutex_t))
+ + 2 * sizeof(size_t) + sizeof(pthread_mutex_t) \
+ + sizeof (pthread_cond_t))
#define shm_rbuff_used(rb)((*rb->ptr_head + SHM_RBUFF_SIZE - *rb->ptr_tail) \
& (SHM_RBUFF_SIZE - 1))
@@ -49,6 +50,7 @@ struct shm_ap_rbuff {
size_t * ptr_head; /* start of ringbuffer head */
size_t * ptr_tail; /* start of ringbuffer tail */
pthread_mutex_t * shm_mutex; /* lock all free space in shm */
+ pthread_cond_t * work; /* threads will wait for a signal */
pid_t pid; /* pid to which this rb belongs */
int fd;
};
@@ -58,7 +60,8 @@ struct shm_ap_rbuff * shm_ap_rbuff_create()
struct shm_ap_rbuff * rb;
int shm_fd;
struct rb_entry * shm_base;
- pthread_mutexattr_t attr;
+ pthread_mutexattr_t mattr;
+ pthread_condattr_t cattr;
char fn[25];
sprintf(fn, SHM_AP_RBUFF_PREFIX "%d", getpid());
@@ -111,10 +114,15 @@ struct shm_ap_rbuff * shm_ap_rbuff_create()
rb->ptr_head = (size_t *) (rb->shm_base + SHM_RBUFF_SIZE);
rb->ptr_tail = rb->ptr_head + 1;
rb->shm_mutex = (pthread_mutex_t *) (rb->ptr_tail + 1);
+ rb->work = (pthread_cond_t *) (rb->shm_mutex + 1);
- pthread_mutexattr_init(&attr);
- pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
- pthread_mutex_init(rb->shm_mutex, &attr);
+ pthread_mutexattr_init(&mattr);
+ pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
+ pthread_mutex_init(rb->shm_mutex, &mattr);
+
+ pthread_condattr_init(&cattr);
+ pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
+ pthread_cond_init(rb->work, &cattr);
*rb->ptr_head = 0;
*rb->ptr_tail = 0;
@@ -169,6 +177,7 @@ struct shm_ap_rbuff * shm_ap_rbuff_open(pid_t pid)
rb->ptr_head = (size_t *) (rb->shm_base + SHM_RBUFF_SIZE);
rb->ptr_tail = rb->ptr_head + 1;
rb->shm_mutex = (pthread_mutex_t *) (rb->ptr_tail + 1);
+ rb->work = (pthread_cond_t *) (rb->shm_mutex + 1);
rb->fd = shm_fd;
rb->pid = pid;
@@ -231,6 +240,9 @@ int shm_ap_rbuff_write(struct shm_ap_rbuff * rb, struct rb_entry * e)
return -1;
}
+ if (shm_rbuff_used(rb) == 0)
+ pthread_cond_broadcast(rb->work);
+
*head_el_ptr = *e;
*rb->ptr_head = (*rb->ptr_head + 1) & (SHM_RBUFF_SIZE -1);
@@ -246,12 +258,14 @@ struct rb_entry * shm_ap_rbuff_read(struct shm_ap_rbuff * rb)
if (rb == NULL)
return NULL;
+ pthread_cleanup_push((void(*)(void *))pthread_mutex_unlock,
+ (void*) rb->shm_mutex);
+
pthread_mutex_lock(rb->shm_mutex);
+ while(shm_rbuff_used(rb) == 0)
+ pthread_cond_wait(rb->work, rb->shm_mutex);
- if (shm_rbuff_used(rb) == 0) {
- pthread_mutex_unlock(rb->shm_mutex);
- return NULL;
- }
+ pthread_cleanup_pop(0);
e = malloc(sizeof(*e));
if (e == NULL) {