X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/a66a4963498d08094fc16c2b0afe6faf8ad512b0..7eb850ef0e437323e2d84157ddc2e6e82af57bbc:/src/debug.c?ds=inline

diff --git a/src/debug.c b/src/debug.c
index 8d51e959..566b2b95 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -7,6 +7,7 @@
 #ifdef HAVE_BACKTRACE
 #include <execinfo.h>
 #include <ucontext.h>
+#include <fcntl.h>
 #endif /* HAVE_BACKTRACE */
 
 /* ================================= Debugging ============================== */
@@ -217,6 +218,10 @@ void computeDatasetDigest(unsigned char *final) {
 void debugCommand(redisClient *c) {
     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
         *((char*)-1) = 'x';
+    } else if (!strcasecmp(c->argv[1]->ptr,"oom")) {
+        void *ptr = zmalloc(ULONG_MAX); /* Should trigger an out of memory. */
+        zfree(ptr);
+        addReply(c,shared.ok);
     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
         redisAssertWithInfo(c,c->argv[0],1 == 2);
@@ -567,27 +572,30 @@ void logRegisters(ucontext_t *uc) {
 #endif
 }
 
-/* Logs the stack trace using the backtrace() call. */
-sds getStackTrace(ucontext_t *uc) {
+/* Logs the stack trace using the backtrace() call. This function is designed
+ * to be called from signal handlers safely. */
+void logStackTrace(ucontext_t *uc) {
     void *trace[100];
-    int i, trace_size = 0;
-    char **messages = NULL;
-    sds st = sdsempty();
+    int trace_size = 0, fd;
+
+    /* Open the log file in append mode. */
+    fd = server.logfile ?
+        open(server.logfile, O_APPEND|O_CREAT|O_WRONLY, 0644) :
+        STDOUT_FILENO;
+    if (fd == -1) return;
 
     /* Generate the stack trace */
     trace_size = backtrace(trace, 100);
 
     /* overwrite sigaction with caller's address */
-    if (getMcontextEip(uc) != NULL) {
+    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;
+
+    /* Write symbols to log file */
+    backtrace_symbols_fd(trace, trace_size, fd);
+
+    /* Cleanup */
+    if (server.logfile) close(fd);
 }
 
 /* Log information about the "current" client, that is, the client that is
@@ -630,7 +638,7 @@ void logCurrentClient(void) {
 
 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
     ucontext_t *uc = (ucontext_t*) secret;
-    sds infostring, clients, st;
+    sds infostring, clients;
     struct sigaction act;
     REDIS_NOTUSED(info);
 
@@ -642,9 +650,8 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
                         server.assert_file, server.assert_line);
 
     /* Log the stack trace */
-    st = getStackTrace(uc);
-    redisLog(REDIS_WARNING, "--- STACK TRACE\n%s", st);
-    sdsfree(st);
+    redisLog(REDIS_WARNING, "--- STACK TRACE");
+    logStackTrace(uc);
 
     /* Log INFO and CLIENT LIST */
     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
@@ -683,6 +690,30 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
 }
 #endif /* HAVE_BACKTRACE */
 
+/* ==================== Logging functions for debugging ===================== */
+
+void redisLogHexDump(int level, char *descr, void *value, size_t len) {
+    char buf[65], *b;
+    unsigned char *v = value;
+    char charset[] = "0123456789abcdef";
+
+    redisLog(level,"%s (hexdump):", descr);
+    b = buf;
+    while(len) {
+        b[0] = charset[(*v)>>4];
+        b[1] = charset[(*v)&0xf];
+        b[2] = '\0';
+        b += 2;
+        len--;
+        v++;
+        if (b-buf == 64 || len == 0) {
+            redisLogRaw(level|REDIS_LOG_RAW,buf);
+            b = buf;
+        }
+    }
+    redisLogRaw(level|REDIS_LOG_RAW,"\n");
+}
+
 /* =========================== Software Watchdog ============================ */
 #include <sys/time.h>
 
@@ -692,19 +723,14 @@ void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
 #endif
     REDIS_NOTUSED(info);
     REDIS_NOTUSED(sig);
-    sds st, log;
 
-    log = sdsnew("\n--- WATCHDOG TIMER EXPIRED ---\n");
+    redisLogFromHandler(REDIS_WARNING,"\n--- WATCHDOG TIMER EXPIRED ---");
 #ifdef HAVE_BACKTRACE
-    st = getStackTrace(uc);
+    logStackTrace(uc);
 #else
-    st = sdsnew("Sorry: no support for backtrace().\n");
+    redisLogFromHandler(REDIS_WARNING,"Sorry: no support for backtrace().");
 #endif
-    log = sdscatsds(log,st);
-    log = sdscat(log,"------\n");
-    redisLogFromHandler(REDIS_WARNING,log);
-    sdsfree(st);
-    sdsfree(log);
+    redisLogFromHandler(REDIS_WARNING,"--------\n");
 }
 
 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
@@ -724,6 +750,8 @@ void watchdogScheduleSignal(int period) {
 
 /* Enable the software watchdong with the specified period in milliseconds. */
 void enableWatchdog(int period) {
+    int min_period;
+
     if (server.watchdog_period == 0) {
         struct sigaction act;
 
@@ -734,7 +762,11 @@ void enableWatchdog(int period) {
         act.sa_sigaction = watchdogSignalHandler;
         sigaction(SIGALRM, &act, NULL);
     }
-    if (period < 200) period = 200; /* We don't accept periods < 200 ms. */
+    /* If the configured period is smaller than twice the timer period, it is
+     * too short for the software watchdog to work reliably. Fix it now
+     * if needed. */
+    min_period = (1000/REDIS_HZ)*2;
+    if (period < min_period) period = min_period;
     watchdogScheduleSignal(period); /* Adjust the current timer. */
     server.watchdog_period = period;
 }