SIGSEGV handler refactored so that we can reuse stack trace and current client...

SIGSEGV handler refactored so that we can reuse stack trace and current client logging functionalities in other contexts.

src/debug.c

@@ -558,21 +558,11 @@ void logRegisters(ucontext_t *uc) {
 #endif
 }
 
-void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
+/* Logs the stack trace using the backtrace() call. */
+void logStackTrace(ucontext_t *uc) {
     void *trace[100];
-    char **messages = NULL;
     int i, trace_size = 0;
-    ucontext_t *uc = (ucontext_t*) secret;
-    sds infostring, clients;
-    struct sigaction act;
-    REDIS_NOTUSED(info);
-
-    bugReportStart();
-    redisLog(REDIS_WARNING,
-        "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
-    redisLog(REDIS_WARNING,
-        "    Failed assertion: %s (%s:%d)", server.assert_failed,
-                        server.assert_file, server.assert_line);
+    char **messages = NULL;
 
     /* Generate the stack trace */
     trace_size = backtrace(trace, 100);
@@ -585,6 +575,61 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
     redisLog(REDIS_WARNING, "--- STACK TRACE");
     for (i=1; i<trace_size; ++i)
         redisLog(REDIS_WARNING,"%s", messages[i]);
+}
+
+/* Log information about the "current" client, that is, the client that is
+ * currently being served by Redis. May be NULL if Redis is not serving a
+ * client right now. */
+void logCurrentClient(void) {
+    if (server.current_client == NULL) return;
+
+    redisClient *cc = server.current_client;
+    sds client;
+    int j;
+
+    redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
+    client = getClientInfoString(cc);
+    redisLog(REDIS_WARNING,"client: %s", client);
+    sdsfree(client);
+    for (j = 0; j < cc->argc; j++) {
+        robj *decoded;
+
+        decoded = getDecodedObject(cc->argv[j]);
+        redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
+        decrRefCount(decoded);
+    }
+    /* Check if the first argument, usually a key, is found inside the
+     * selected DB, and if so print info about the associated object. */
+    if (cc->argc >= 1) {
+        robj *val, *key;
+        dictEntry *de;
+
+        key = getDecodedObject(cc->argv[1]);
+        de = dictFind(cc->db->dict, key->ptr);
+        if (de) {
+            val = dictGetVal(de);
+            redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
+            redisLogObjectDebugInfo(val);
+        }
+        decrRefCount(key);
+    }
+}
+
+void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
+    ucontext_t *uc = (ucontext_t*) secret;
+    sds infostring, clients;
+    struct sigaction act;
+    REDIS_NOTUSED(info);
+
+    bugReportStart();
+    redisLog(REDIS_WARNING,
+        "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
+    redisLog(REDIS_WARNING,
+        "    Failed assertion: %s (%s:%d)", server.assert_failed,
+                        server.assert_file, server.assert_line);
+
+    /* Log the stack trace */
+    logStackTrace(uc);
 
     /* Log INFO and CLIENT LIST */
     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
@@ -595,41 +640,11 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
     clients = getAllClientsInfoString();
     redisLogRaw(REDIS_WARNING, clients);
-    /* Don't sdsfree() strings to avoid a crash. Memory may be corrupted. */
-
-    /* Log CURRENT CLIENT info */
-    if (server.current_client) {
-        redisClient *cc = server.current_client;
-        sds client;
-        int j;
+    sdsfree(infostring);
+    sdsfree(clients);
 
-        redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
-        client = getClientInfoString(cc);
-        redisLog(REDIS_WARNING,"client: %s", client);
-        /* Missing sdsfree(client) to avoid crash if memory is corrupted. */
-        for (j = 0; j < cc->argc; j++) {
-            robj *decoded;
-
-            decoded = getDecodedObject(cc->argv[j]);
-            redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
-            decrRefCount(decoded);
-        }
-        /* Check if the first argument, usually a key, is found inside the
-         * selected DB, and if so print info about the associated object. */
-        if (cc->argc >= 1) {
-            robj *val, *key;
-            dictEntry *de;
-
-            key = getDecodedObject(cc->argv[1]);
-            de = dictFind(cc->db->dict, key->ptr);
-            if (de) {
-                val = dictGetVal(de);
-                redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
-                redisLogObjectDebugInfo(val);
-            }
-            decrRefCount(key);
-        }
-    }
+    /* Log the current client */
+    logCurrentClient();
 
     /* Log dump of processor registers */
     logRegisters(uc);