Unlock of shared memory zones on process crash.

If process exited abnormally while holding lock on some shared memory zone -
unlock it.  It may be not safe thing to do (as crash with lock held may
result in corrupted shared memory structure, and other processes will
subsequently crash while trying to access shared data), therefore complain
loudly if unlock succeeds.

diff --git a/src/os/unix/ngx_process.c b/src/os/unix/ngx_process.c
index cbdae8be1614e374a1aa6e03ff081c61e8756942..9f1936bd1fd06acf2188029d9c9c7c7876da06e7 100644 (file)
--- a/src/os/unix/ngx_process.c
+++ b/src/os/unix/ngx_process.c
@@ -22,6 +22,7 @@ typedef struct {
 static void ngx_execute_proc(ngx_cycle_t *cycle, void *data);
 static void ngx_signal_handler(int signo);
 static void ngx_process_get_status(void);
+static void ngx_unlock_mutexes(ngx_pid_t pid);
 
 
 int              ngx_argc;
@@ -497,17 +498,6 @@ ngx_process_get_status(void)
         }
 
 
-        if (ngx_accept_mutex_ptr) {
-
-            /*
-             * unlock the accept mutex if the abnormally exited process
-             * held it
-             */
-
-            ngx_shmtx_force_unlock(&ngx_accept_mutex, pid);
-        }
-
-
         one = 1;
         process = "unknown process";
 
@@ -545,6 +535,55 @@ ngx_process_get_status(void)
                           process, pid, WEXITSTATUS(status));
             ngx_processes[i].respawn = 0;
         }
+
+        ngx_unlock_mutexes(pid);
+    }
+}
+
+
+static void
+ngx_unlock_mutexes(ngx_pid_t pid)
+{ 
+    ngx_uint_t        i;
+    ngx_shm_zone_t   *shm_zone;
+    ngx_list_part_t  *part;
+    ngx_slab_pool_t  *sp;
+
+    /*
+     * unlock the accept mutex if the abnormally exited process
+     * held it
+     */
+
+    if (ngx_accept_mutex_ptr) {
+        ngx_shmtx_force_unlock(&ngx_accept_mutex, pid);
+    }
+
+    /*
+     * unlock shared memory mutexes if held by the abnormally exited
+     * process
+     */
+
+    part = (ngx_list_part_t *) &ngx_cycle->shared_memory.part;
+    shm_zone = part->elts;
+
+    for (i = 0; /* void */ ; i++) {
+
+        if (i >= part->nelts) {
+            if (part->next == NULL) {
+                break;
+            }
+            part = part->next;
+            shm_zone = part->elts;
+            i = 0;
+        }
+
+        sp = (ngx_slab_pool_t *) shm_zone[i].shm.addr;
+
+        if (ngx_shmtx_force_unlock(&sp->mutex, pid)) {
+            ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
+                          "shared memory zone \"%V\" was locked by %P",
+                          &shm_zone[i].shm.name, pid);
+        }
     }
 }