X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/e4669c045d5bc0f7420814cb66f13f03ac29e29a..6aa2f98938955788c3f56e1ce8fef691233bca35:/src/debug.c

diff --git a/src/debug.c b/src/debug.c
index 9c8b6ef9..e7b3ba40 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -559,10 +559,11 @@ void logRegisters(ucontext_t *uc) {
 }
 
 /* Logs the stack trace using the backtrace() call. */
-void logStackTrace(ucontext_t *uc) {
+sds getStackTrace(ucontext_t *uc) {
     void *trace[100];
     int i, trace_size = 0;
     char **messages = NULL;
+    sds st = sdsempty();
 
     /* Generate the stack trace */
     trace_size = backtrace(trace, 100);
@@ -572,9 +573,12 @@ void logStackTrace(ucontext_t *uc) {
         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]);
+    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
@@ -617,7 +621,7 @@ void logCurrentClient(void) {
 
 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
     ucontext_t *uc = (ucontext_t*) secret;
-    sds infostring, clients;
+    sds infostring, clients, st;
     struct sigaction act;
     REDIS_NOTUSED(info);
 
@@ -629,7 +633,9 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
                         server.assert_file, server.assert_line);
 
     /* Log the stack trace */
-    logStackTrace(uc);
+    st = getStackTrace(uc);
+    redisLog(REDIS_WARNING, "--- STACK TRACE\n%s", st);
+    sdsfree(st);
 
     /* Log INFO and CLIENT LIST */
     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
@@ -661,11 +667,78 @@ 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);
-    /* 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 */
+
+/* =========================== 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;
+
+    log = sdsnew("\n--- WATCHDOG TIMER EXPIRED ---\n");
+#ifdef HAVE_BACKTRACE
+    st = getStackTrace(uc);
+#else
+    st = sdsnew("Sorry: no support for backtrace().\n");
+#endif
+    log = sdscatsds(log,st);
+    log = sdscat(log,"------\n");
+    redisLogFromHandler(REDIS_WARNING,log);
+    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;
+}