Produce the watchlog warning log in a way that is safer from a signal handler. Fix...

[redis.git] / src / debug.c

diff --git a/src/debug.c b/src/debug.c
index a355df05f6dc65fdc203374678a6909644c10d37..49c76824d2223c66a6a7804006bf702d43a46ab8 100644 (file)
--- a/src/debug.c
+++ b/src/debug.c
@@ -558,12 +558,70 @@ void logRegisters(ucontext_t *uc) {
 #endif
 }
 
 #endif
 }
 

-void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
+/* Logs the stack trace using the backtrace() call. */
+sds getStackTrace(ucontext_t *uc) {

     void *trace[100];
     void *trace[100];

-    char **messages = NULL;

     int i, trace_size = 0;
     int i, trace_size = 0;

+    char **messages = NULL;
+    sds st = sdsempty();
+
+    /* Generate the stack trace */
+    trace_size = backtrace(trace, 100);
+
+    /* overwrite sigaction with caller's address */
+    if (getMcontextEip(uc) != NULL) {
+        trace[1] = getMcontextEip(uc);
+    }
+    messages = backtrace_symbols(trace, trace_size);
+    for (i=1; i<trace_size; ++i) {
+        st = sdscat(st,messages[i]);
+        st = sdscatlen(st,"\n",1);
+    }
+    zlibc_free(messages);
+    return st;
+}
+
+/* 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;
     ucontext_t *uc = (ucontext_t*) secret;

-    sds infostring, clients;
+    sds infostring, clients, st;

     struct sigaction act;
     REDIS_NOTUSED(info);
 
     struct sigaction act;
     REDIS_NOTUSED(info);
 


@@ -574,17 +632,10 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
         "    Failed assertion: %s (%s:%d)", server.assert_failed,
                         server.assert_file, server.assert_line);
 
         "    Failed assertion: %s (%s:%d)", server.assert_failed,
                         server.assert_file, server.assert_line);
 

-    /* Generate the stack trace */
-    trace_size = backtrace(trace, 100);
-
-    /* overwrite sigaction with caller's address */
-    if (getMcontextEip(uc) != NULL) {
-        trace[1] = getMcontextEip(uc);
-    }
-    messages = backtrace_symbols(trace, trace_size);
-    redisLog(REDIS_WARNING, "--- STACK TRACE");
-    for (i=1; i<trace_size; ++i)
-        redisLog(REDIS_WARNING,"%s", messages[i]);
+    /* Log the stack trace */
+    st = getStackTrace(uc);
+    redisLog(REDIS_WARNING, "--- STACK TRACE\n%s", st);
+    sdsfree(st);

 
     /* Log INFO and CLIENT LIST */
     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
 
     /* Log INFO and CLIENT LIST */
     redisLog(REDIS_WARNING, "--- INFO OUTPUT");


@@ -595,49 +646,20 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
     clients = getAllClientsInfoString();
     redisLogRaw(REDIS_WARNING, clients);
     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);
 
     redisLog(REDIS_WARNING,
 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
 
     /* Log dump of processor registers */
     logRegisters(uc);
 
     redisLog(REDIS_WARNING,
 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"

-"    Please report the crash opening an issue on github:\n\n"
-"        http://github.com/antirez/redis/issues\n\n"
+"       Please report the crash opening an issue on github:\n\n"
+"           http://github.com/antirez/redis/issues\n\n"
+"  Suspect RAM error? Use redis-server --test-memory to veryfy it.\n\n"

 );
     /* free(messages); Don't call free() with possibly corrupted memory. */
     if (server.daemonize) unlink(server.pidfile);
 );
     /* free(messages); Don't call free() with possibly corrupted memory. */
     if (server.daemonize) unlink(server.pidfile);


@@ -645,11 +667,87 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
     /* Make sure we exit with the right signal at the end. So for instance
      * the core will be dumped if enabled. */
     sigemptyset (&act.sa_mask);
     /* Make sure we exit with the right signal at the end. So for instance
      * the core will be dumped if enabled. */
     sigemptyset (&act.sa_mask);

-    /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
-     * is used. Otherwise, sa_handler is used */

     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
     act.sa_handler = SIG_DFL;
     sigaction (sig, &act, NULL);
     kill(getpid(),sig);
 }
 #endif /* HAVE_BACKTRACE */
     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
     act.sa_handler = SIG_DFL;
     sigaction (sig, &act, NULL);
     kill(getpid(),sig);
 }
 #endif /* HAVE_BACKTRACE */

+
+/* =========================== Software Watchdog ============================ */
+#include <sys/time.h>
+
+void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
+    ucontext_t *uc = (ucontext_t*) secret;
+    REDIS_NOTUSED(info);
+    REDIS_NOTUSED(sig);
+    sds st, log;
+    time_t now = time(NULL);
+    char date[128];
+    FILE *fp;
+
+    fp = (server.logfile == NULL) ? stdout : fopen(server.logfile,"a");
+    if (fp == NULL) return;
+
+    strftime(date,sizeof(date),"%d %b %H:%M:%S",localtime(&now));
+    log = sdscatprintf(sdsempty(),
+        "\n--- WATCHDOG TIMER EXPIRED (%s) ---\n",date); 
+#ifdef HAVE_BACKTRACE
+    st = getStackTrace(uc);
+#else
+    st = sdsnew("Sorry: no support for backtrace().\n");
+#endif
+    log = sdscatsds(log,st);
+    log = sdscat(log,"------\n\n");
+    fprintf(fp,"%s",log);
+    if (server.logfile) fclose(fp);
+    sdsfree(st);
+    sdsfree(log);
+}
+
+/* Schedule a SIGALRM delivery after the specified period in milliseconds.
+ * If a timer is already scheduled, this function will re-schedule it to the
+ * specified time. If period is 0 the current timer is disabled. */
+void watchdogScheduleSignal(int period) {
+    struct itimerval it;
+
+    /* Will stop the timer if period is 0. */
+    it.it_value.tv_sec = period/1000;
+    it.it_value.tv_usec = (period%1000)*1000;
+    /* Don't automatically restart. */
+    it.it_interval.tv_sec = 0;
+    it.it_interval.tv_usec = 0;
+    setitimer(ITIMER_REAL, &it, NULL);
+}
+
+/* Enable the software watchdong with the specified period in milliseconds. */
+void enableWatchdog(int period) {
+    if (server.watchdog_period == 0) {
+        struct sigaction act;
+
+        /* Watchdog was actually disabled, so we have to setup the signal
+         * handler. */
+        sigemptyset(&act.sa_mask);
+        act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_SIGINFO;
+        act.sa_sigaction = watchdogSignalHandler;
+        sigaction(SIGALRM, &act, NULL);
+    }
+    if (period < 200) period = 200; /* We don't accept periods < 200 ms. */
+    watchdogScheduleSignal(period); /* Adjust the current timer. */
+    server.watchdog_period = period;
+}
+
+/* Disable the software watchdog. */
+void disableWatchdog(void) {
+    struct sigaction act;
+    if (server.watchdog_period == 0) return; /* Already disabled. */
+    watchdogScheduleSignal(0); /* Stop the current timer. */
+
+    /* Set the signal handler to SIG_IGN, this will also remove pending
+     * signals from the queue. */
+    sigemptyset(&act.sa_mask);
+    act.sa_flags = 0;
+    act.sa_handler = SIG_IGN;
+    sigaction(SIGALRM, &act, NULL);
+    server.watchdog_period = 0;
+}