refactor code, remove global lock and shared memory when count of semaphore is 0

Author: YvesDup

Modules/_multiprocessing/dump_shm_macosx/dump_shared_mem.c

@@ -14,10 +14,9 @@ typedef sem_t *SEM_HANDLE;
 // Static datas for each process.
 CountersWorkaround shm_semlock_counters = {
     .state_this = THIS_NOT_OPEN,
-    .name_shm = "/shm_gh125828",
+    .name_shm = SHAREDMEM_NAME,
     .handle_shm = (MEMORY_HANDLE)0,
-    .create_shm = 0,
-    .name_shm_lock = "/mp_gh125828",
+    .name_shm_lock = GLOCK_NAME,
     .handle_shm_lock = (SEM_HANDLE)0,
     .header = (HeaderObject *)NULL,
     .counters = (CounterObject *)NULL,
@@ -27,10 +26,9 @@ HeaderObject *header = NULL;
 CounterObject *counter =  NULL;
 
 static char *show_counter(char *p, CounterObject *counter) {
-    sprintf(p, "p:%p, n:%s, v:%d, u:%d, t:%s", counter,
+    sprintf(p, "p:%p, n:%s, v:%d, t:%s", counter,
                                            counter->sem_name,
                                            counter->internal_value,
-                                           counter->unlink_done,
                                            ctime(&counter->ctimestamp));
     return p;
 }
@@ -73,7 +71,7 @@ int main(int argc, char *argv[]) {
     puts("+++++++++");
     if (argc > 1) {
         sscanf(argv[1], "%d", &repeat);
-        if (argc >= 2) {
+        if (argc > 2) {
             puts(argv[2]);
             sscanf(argv[2], "%lu", &udelay);
         }
@@ -88,13 +86,17 @@ int main(int argc, char *argv[]) {
     if (shm_semlock_counters.state_this == THIS_AVAILABLE) {
         memset(&save, '\0', sizeof(save));
         do {
+            //ACQUIRE_SHM_LOCK;
+            acquire_lock(shm_semlock_counters.handle_shm_lock);
             if (memcmp(&save, shm_semlock_counters.header, sizeof(HeaderObject)) ) {
                 time_t timestamp = time(NULL);
                 puts(ctime(&timestamp));
                 dump_shm_semlock_counters();
                 memcpy(&save, shm_semlock_counters.header, sizeof(HeaderObject));
                 puts("==========");
             }
+            //RELEASE_SHM_LOCK;
+            sem_post(shm_semlock_counters.handle_shm_lock);
             usleep(udelay);
         } while(repeat--);
     }

Modules/_multiprocessing/dump_shm_macosx/reset_shared_mem.c

@@ -11,10 +11,9 @@ typedef sem_t *SEM_HANDLE;
 // Static datas for each process.
 CountersWorkaround shm_semlock_counters = {
     .state_this = THIS_NOT_OPEN,
-    .name_shm = "/shm_gh125828",
+    .name_shm = SHAREDMEM_NAME,
     .handle_shm = (MEMORY_HANDLE)0,
-    .create_shm = 0,
-    .name_shm_lock = "/mp_gh125828",
+    .name_shm_lock = GLOCK_NAME,
     .handle_shm_lock = (SEM_HANDLE)0,
     .header = (HeaderObject *)NULL,
     .counters = (CounterObject *)NULL,

Modules/_multiprocessing/dump_shm_macosx/shared_mem.c

@@ -25,6 +25,25 @@ int release_lock(SEM_HANDLE sem) {
     return 1;
 }
 
+int exists_lock(SEM_HANDLE sem) {
+    int res = -1 ;
+
+    errno = 0;
+    res = sem_trywait(sem);
+    if (res < 0 ) {
+        if (errno == EBADF) {
+            puts("global lock does not exist");
+            shm_semlock_counters.state_this = THIS_NOT_OPEN;
+            return 0;
+        }
+        return 0;
+    }
+    if (sem_post(sem) < 0) {
+        return 0;
+    }
+    return 1;
+}
+
 void connect_shm_semlock_counters(int unlink, int force_open, int call_release_lock) {
 puts(__func__);
 
@@ -102,24 +121,24 @@ static void _delete_shm_semlock_counters(int unlink) {
     puts("clean up...");
     if (shm_semlock_counters.state_this == THIS_AVAILABLE) {
         if (shm_semlock_counters.counters) {
-            if (ACQUIRE_SHM_LOCK) {
-                // unmmap
-                munmap(shm_semlock_counters.counters,
-                       shm_semlock_counters.header->size_shm);
-                if (unlink) {
-                    shm_unlink(shm_semlock_counters.name_shm);
-                }
-                shm_semlock_counters.state_this = THIS_CLOSED;
-                RELEASE_SHM_LOCK;
+            ACQUIRE_SHM_LOCK;
+            // unmmap
+            munmap(shm_semlock_counters.counters,
+                    shm_semlock_counters.header->size_shm);
+            if (unlink) {
+                shm_unlink(shm_semlock_counters.name_shm);
             }
+            shm_semlock_counters.state_this = THIS_CLOSED;
+            RELEASE_SHM_LOCK;
         }
-        // close lock
-        sem_close(shm_semlock_counters.handle_shm_lock);
-        sem_unlink(shm_semlock_counters.name_shm_lock);
     }
+    // close lock
+    sem_close(shm_semlock_counters.handle_shm_lock);
+    sem_unlink(shm_semlock_counters.name_shm_lock);
 }
 
 
+
 void delete_shm_semlock_counters_without_unlink(void) {
 puts(__func__);
     _delete_shm_semlock_counters(0);

Modules/_multiprocessing/dump_shm_macosx/shared_mem.h

@@ -5,8 +5,8 @@ extern CountersWorkaround shm_semlock_counters;
 extern HeaderObject *header;
 extern CounterObject *counter;
 
-int acquire_lock(SEM_HANDLE sem);
-int release_lock(SEM_HANDLE sem);
+extern int acquire_lock(SEM_HANDLE sem);
+extern int release_lock(SEM_HANDLE sem);
 
 void connect_shm_semlock_counters(int unlink,  int force_connect, int release_lock);
 void delete_shm_semlock_counters_without_unlink(void);