Release notes updated with the new 2.6 features.
[redis.git] / src / debug.c
index 10b620d6f3ade7c37115e29055cd73fbef75922f..42a73883d9d6f0f7ef3eba8511ab7f750de7428b 100644 (file)
@@ -1,6 +1,15 @@
 #include "redis.h"
 #include "sha1.h"   /* SHA1 is used for DEBUG DIGEST */
 
+#include <arpa/inet.h>
+#include <signal.h>
+
+#ifdef HAVE_BACKTRACE
+#include <execinfo.h>
+#include <ucontext.h>
+#include <fcntl.h>
+#endif /* HAVE_BACKTRACE */
+
 /* ================================= Debugging ============================== */
 
 /* Compute the sha1 of string at 's' with 'len' bytes long.
@@ -89,16 +98,15 @@ void computeDatasetDigest(unsigned char *final) {
         while((de = dictNext(di)) != NULL) {
             sds key;
             robj *keyobj, *o;
-            time_t expiretime;
+            long long expiretime;
 
             memset(digest,0,20); /* This key-val digest */
-            key = dictGetEntryKey(de);
+            key = dictGetKey(de);
             keyobj = createStringObject(key,sdslen(key));
 
             mixDigest(digest,key,sdslen(key));
 
-            /* Make sure the key is loaded if VM is active */
-            o = lookupKeyRead(db,keyobj);
+            o = dictGetVal(de);
 
             aux = htonl(o->type);
             mixDigest(digest,&aux,sizeof(aux));
@@ -117,33 +125,65 @@ void computeDatasetDigest(unsigned char *final) {
                 }
                 listTypeReleaseIterator(li);
             } else if (o->type == REDIS_SET) {
-                dict *set = o->ptr;
-                dictIterator *di = dictGetIterator(set);
-                dictEntry *de;
-
-                while((de = dictNext(di)) != NULL) {
-                    robj *eleobj = dictGetEntryKey(de);
-
-                    xorObjectDigest(digest,eleobj);
+                setTypeIterator *si = setTypeInitIterator(o);
+                robj *ele;
+                while((ele = setTypeNextObject(si)) != NULL) {
+                    xorObjectDigest(digest,ele);
+                    decrRefCount(ele);
                 }
-                dictReleaseIterator(di);
+                setTypeReleaseIterator(si);
             } else if (o->type == REDIS_ZSET) {
-                zset *zs = o->ptr;
-                dictIterator *di = dictGetIterator(zs->dict);
-                dictEntry *de;
-
-                while((de = dictNext(di)) != NULL) {
-                    robj *eleobj = dictGetEntryKey(de);
-                    double *score = dictGetEntryVal(de);
-                    unsigned char eledigest[20];
-
-                    snprintf(buf,sizeof(buf),"%.17g",*score);
-                    memset(eledigest,0,20);
-                    mixObjectDigest(eledigest,eleobj);
-                    mixDigest(eledigest,buf,strlen(buf));
-                    xorDigest(digest,eledigest,20);
+                unsigned char eledigest[20];
+
+                if (o->encoding == REDIS_ENCODING_ZIPLIST) {
+                    unsigned char *zl = o->ptr;
+                    unsigned char *eptr, *sptr;
+                    unsigned char *vstr;
+                    unsigned int vlen;
+                    long long vll;
+                    double score;
+
+                    eptr = ziplistIndex(zl,0);
+                    redisAssert(eptr != NULL);
+                    sptr = ziplistNext(zl,eptr);
+                    redisAssert(sptr != NULL);
+
+                    while (eptr != NULL) {
+                        redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
+                        score = zzlGetScore(sptr);
+
+                        memset(eledigest,0,20);
+                        if (vstr != NULL) {
+                            mixDigest(eledigest,vstr,vlen);
+                        } else {
+                            ll2string(buf,sizeof(buf),vll);
+                            mixDigest(eledigest,buf,strlen(buf));
+                        }
+
+                        snprintf(buf,sizeof(buf),"%.17g",score);
+                        mixDigest(eledigest,buf,strlen(buf));
+                        xorDigest(digest,eledigest,20);
+                        zzlNext(zl,&eptr,&sptr);
+                    }
+                } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
+                    zset *zs = o->ptr;
+                    dictIterator *di = dictGetIterator(zs->dict);
+                    dictEntry *de;
+
+                    while((de = dictNext(di)) != NULL) {
+                        robj *eleobj = dictGetKey(de);
+                        double *score = dictGetVal(de);
+
+                        snprintf(buf,sizeof(buf),"%.17g",*score);
+                        memset(eledigest,0,20);
+                        mixObjectDigest(eledigest,eleobj);
+                        mixDigest(eledigest,buf,strlen(buf));
+                        xorDigest(digest,eledigest,20);
+                    }
+                    dictReleaseIterator(di);
+                } else {
+                    redisPanic("Unknown sorted set encoding");
                 }
-                dictReleaseIterator(di);
             } else if (o->type == REDIS_HASH) {
                 hashTypeIterator *hi;
                 robj *obj;
@@ -153,10 +193,10 @@ void computeDatasetDigest(unsigned char *final) {
                     unsigned char eledigest[20];
 
                     memset(eledigest,0,20);
-                    obj = hashTypeCurrent(hi,REDIS_HASH_KEY);
+                    obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
                     mixObjectDigest(eledigest,obj);
                     decrRefCount(obj);
-                    obj = hashTypeCurrent(hi,REDIS_HASH_VALUE);
+                    obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
                     mixObjectDigest(eledigest,obj);
                     decrRefCount(obj);
                     xorDigest(digest,eledigest,20);
@@ -178,81 +218,49 @@ 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,"assert")) {
+        if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
+        redisAssertWithInfo(c,c->argv[0],1 == 2);
     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
-        if (rdbSave(server.dbfilename) != REDIS_OK) {
+        if (rdbSave(server.rdb_filename) != REDIS_OK) {
             addReply(c,shared.err);
             return;
         }
         emptyDb();
-        if (rdbLoad(server.dbfilename) != REDIS_OK) {
-            addReply(c,shared.err);
+        if (rdbLoad(server.rdb_filename) != REDIS_OK) {
+            addReplyError(c,"Error trying to load the RDB dump");
             return;
         }
         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
         addReply(c,shared.ok);
     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
         emptyDb();
-        if (loadAppendOnlyFile(server.appendfilename) != REDIS_OK) {
+        if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
             addReply(c,shared.err);
             return;
         }
+        server.dirty = 0; /* Prevent AOF / replication */
         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
         addReply(c,shared.ok);
     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
-        dictEntry *de = dictFind(c->db->dict,c->argv[2]->ptr);
+        dictEntry *de;
         robj *val;
+        char *strenc;
 
-        if (!de) {
+        if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
             addReply(c,shared.nokeyerr);
             return;
         }
-        val = dictGetEntryVal(de);
-        if (!server.vm_enabled || (val->storage == REDIS_VM_MEMORY ||
-                                   val->storage == REDIS_VM_SWAPPING)) {
-            char *strenc;
-
-            strenc = strEncoding(val->encoding);
-            addReplySds(c,sdscatprintf(sdsempty(),
-                "+Value at:%p refcount:%d "
-                "encoding:%s serializedlength:%lld\r\n",
-                (void*)val, val->refcount,
-                strenc, (long long) rdbSavedObjectLen(val,NULL)));
-        } else {
-            vmpointer *vp = (vmpointer*) val;
-            addReplySds(c,sdscatprintf(sdsempty(),
-                "+Value swapped at: page %llu "
-                "using %llu pages\r\n",
-                (unsigned long long) vp->page,
-                (unsigned long long) vp->usedpages));
-        }
-    } else if (!strcasecmp(c->argv[1]->ptr,"swapin") && c->argc == 3) {
-        lookupKeyRead(c->db,c->argv[2]);
-        addReply(c,shared.ok);
-    } else if (!strcasecmp(c->argv[1]->ptr,"swapout") && c->argc == 3) {
-        dictEntry *de = dictFind(c->db->dict,c->argv[2]->ptr);
-        robj *val;
-        vmpointer *vp;
-
-        if (!server.vm_enabled) {
-            addReplySds(c,sdsnew("-ERR Virtual Memory is disabled\r\n"));
-            return;
-        }
-        if (!de) {
-            addReply(c,shared.nokeyerr);
-            return;
-        }
-        val = dictGetEntryVal(de);
-        /* Swap it */
-        if (val->storage != REDIS_VM_MEMORY) {
-            addReplySds(c,sdsnew("-ERR This key is not in memory\r\n"));
-        } else if (val->refcount != 1) {
-            addReplySds(c,sdsnew("-ERR Object is shared\r\n"));
-        } else if ((vp = vmSwapObjectBlocking(val)) != NULL) {
-            dictGetEntryVal(de) = vp;
-            addReply(c,shared.ok);
-        } else {
-            addReply(c,shared.err);
-        }
+        val = dictGetVal(de);
+        strenc = strEncoding(val->encoding);
+
+        addReplyStatusFormat(c,
+            "Value at:%p refcount:%d "
+            "encoding:%s serializedlength:%lld "
+            "lru:%d lru_seconds_idle:%lu",
+            (void*)val, val->refcount,
+            strenc, (long long) rdbSavedObjectLen(val),
+            val->lru, estimateObjectIdleTime(val));
     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
         long keys, j;
         robj *key, *val;
@@ -275,35 +283,471 @@ void debugCommand(redisClient *c) {
         addReply(c,shared.ok);
     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
         unsigned char digest[20];
-        sds d = sdsnew("+");
+        sds d = sdsempty();
         int j;
 
         computeDatasetDigest(digest);
         for (j = 0; j < 20; j++)
             d = sdscatprintf(d, "%02x",digest[j]);
+        addReplyStatus(c,d);
+        sdsfree(d);
+    } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
+        double dtime = strtod(c->argv[2]->ptr,NULL);
+        long long utime = dtime*1000000;
 
-        d = sdscatlen(d,"\r\n",2);
-        addReplySds(c,d);
+        usleep(utime);
+        addReply(c,shared.ok);
     } else {
-        addReplySds(c,sdsnew(
-            "-ERR Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]\r\n"));
+        addReplyError(c,
+            "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
     }
 }
 
+/* =========================== Crash handling  ============================== */
+
 void _redisAssert(char *estr, char *file, int line) {
+    bugReportStart();
     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
 #ifdef HAVE_BACKTRACE
-    redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
-    *((char*)-1) = 'x';
+    server.assert_failed = estr;
+    server.assert_file = file;
+    server.assert_line = line;
+    redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
 #endif
+    *((char*)-1) = 'x';
+}
+
+void _redisAssertPrintClientInfo(redisClient *c) {
+    int j;
+
+    bugReportStart();
+    redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
+    redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
+    redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
+    redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
+    for (j=0; j < c->argc; j++) {
+        char buf[128];
+        char *arg;
+
+        if (c->argv[j]->type == REDIS_STRING &&
+            c->argv[j]->encoding == REDIS_ENCODING_RAW)
+        {
+            arg = (char*) c->argv[j]->ptr;
+        } else {
+            snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
+                c->argv[j]->type, c->argv[j]->encoding);
+            arg = buf;
+        }
+        redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
+            j, arg, c->argv[j]->refcount);
+    }
+}
+
+void redisLogObjectDebugInfo(robj *o) {
+    redisLog(REDIS_WARNING,"Object type: %d", o->type);
+    redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
+    redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
+    if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
+        redisLog(REDIS_WARNING,"Object raw string len: %d", sdslen(o->ptr));
+        if (sdslen(o->ptr) < 4096)
+            redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
+    } else if (o->type == REDIS_LIST) {
+        redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
+    } else if (o->type == REDIS_SET) {
+        redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
+    } else if (o->type == REDIS_HASH) {
+        redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
+    } else if (o->type == REDIS_ZSET) {
+        redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
+        if (o->encoding == REDIS_ENCODING_SKIPLIST)
+            redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
+    }
+}
+
+void _redisAssertPrintObject(robj *o) {
+    bugReportStart();
+    redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
+    redisLogObjectDebugInfo(o);
+}
+
+void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
+    if (c) _redisAssertPrintClientInfo(c);
+    if (o) _redisAssertPrintObject(o);
+    _redisAssert(estr,file,line);
 }
 
 void _redisPanic(char *msg, char *file, int line) {
+    bugReportStart();
+    redisLog(REDIS_WARNING,"------------------------------------------------");
     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
 #ifdef HAVE_BACKTRACE
     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
+#endif
+    redisLog(REDIS_WARNING,"------------------------------------------------");
     *((char*)-1) = 'x';
+}
+
+void bugReportStart(void) {
+    if (server.bug_report_start == 0) {
+        redisLog(REDIS_WARNING,
+            "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
+        server.bug_report_start = 1;
+    }
+}
+
+#ifdef HAVE_BACKTRACE
+static void *getMcontextEip(ucontext_t *uc) {
+#if defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
+    /* OSX < 10.6 */
+    #if defined(__x86_64__)
+    return (void*) uc->uc_mcontext->__ss.__rip;
+    #elif defined(__i386__)
+    return (void*) uc->uc_mcontext->__ss.__eip;
+    #else
+    return (void*) uc->uc_mcontext->__ss.__srr0;
+    #endif
+#elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
+    /* OSX >= 10.6 */
+    #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
+    return (void*) uc->uc_mcontext->__ss.__rip;
+    #else
+    return (void*) uc->uc_mcontext->__ss.__eip;
+    #endif
+#elif defined(__linux__)
+    /* Linux */
+    #if defined(__i386__)
+    return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
+    #elif defined(__X86_64__) || defined(__x86_64__)
+    return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
+    #elif defined(__ia64__) /* Linux IA64 */
+    return (void*) uc->uc_mcontext.sc_ip;
+    #endif
+#else
+    return NULL;
+#endif
+}
+
+void logStackContent(void **sp) {
+    int i;
+    for (i = 15; i >= 0; i--) {
+        if (sizeof(long) == 4)
+            redisLog(REDIS_WARNING, "(%08lx) -> %08lx", sp+i, sp[i]);
+        else
+            redisLog(REDIS_WARNING, "(%016lx) -> %016lx", sp+i, sp[i]);
+    }
+}
+
+void logRegisters(ucontext_t *uc) {
+    redisLog(REDIS_WARNING, "--- REGISTERS");
+
+/* OSX */
+#if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
+  /* OSX AMD64 */
+    #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
+    redisLog(REDIS_WARNING,
+    "\n"
+    "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
+    "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
+    "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
+    "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
+    "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
+        uc->uc_mcontext->__ss.__rax,
+        uc->uc_mcontext->__ss.__rbx,
+        uc->uc_mcontext->__ss.__rcx,
+        uc->uc_mcontext->__ss.__rdx,
+        uc->uc_mcontext->__ss.__rdi,
+        uc->uc_mcontext->__ss.__rsi,
+        uc->uc_mcontext->__ss.__rbp,
+        uc->uc_mcontext->__ss.__rsp,
+        uc->uc_mcontext->__ss.__r8,
+        uc->uc_mcontext->__ss.__r9,
+        uc->uc_mcontext->__ss.__r10,
+        uc->uc_mcontext->__ss.__r11,
+        uc->uc_mcontext->__ss.__r12,
+        uc->uc_mcontext->__ss.__r13,
+        uc->uc_mcontext->__ss.__r14,
+        uc->uc_mcontext->__ss.__r15,
+        uc->uc_mcontext->__ss.__rip,
+        uc->uc_mcontext->__ss.__rflags,
+        uc->uc_mcontext->__ss.__cs,
+        uc->uc_mcontext->__ss.__fs,
+        uc->uc_mcontext->__ss.__gs
+    );
+    logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
+    #else
+    /* OSX x86 */
+    redisLog(REDIS_WARNING,
+    "\n"
+    "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
+    "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
+    "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
+    "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
+        uc->uc_mcontext->__ss.__eax,
+        uc->uc_mcontext->__ss.__ebx,
+        uc->uc_mcontext->__ss.__ecx,
+        uc->uc_mcontext->__ss.__edx,
+        uc->uc_mcontext->__ss.__edi,
+        uc->uc_mcontext->__ss.__esi,
+        uc->uc_mcontext->__ss.__ebp,
+        uc->uc_mcontext->__ss.__esp,
+        uc->uc_mcontext->__ss.__ss,
+        uc->uc_mcontext->__ss.__eflags,
+        uc->uc_mcontext->__ss.__eip,
+        uc->uc_mcontext->__ss.__cs,
+        uc->uc_mcontext->__ss.__ds,
+        uc->uc_mcontext->__ss.__es,
+        uc->uc_mcontext->__ss.__fs,
+        uc->uc_mcontext->__ss.__gs
+    );
+    logStackContent((void**)uc->uc_mcontext->__ss.__esp);
+    #endif
+/* Linux */
+#elif defined(__linux__)
+    /* Linux x86 */
+    #if defined(__i386__)
+    redisLog(REDIS_WARNING,
+    "\n"
+    "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
+    "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
+    "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
+    "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
+        uc->uc_mcontext.gregs[11],
+        uc->uc_mcontext.gregs[8],
+        uc->uc_mcontext.gregs[10],
+        uc->uc_mcontext.gregs[9],
+        uc->uc_mcontext.gregs[4],
+        uc->uc_mcontext.gregs[5],
+        uc->uc_mcontext.gregs[6],
+        uc->uc_mcontext.gregs[7],
+        uc->uc_mcontext.gregs[18],
+        uc->uc_mcontext.gregs[17],
+        uc->uc_mcontext.gregs[14],
+        uc->uc_mcontext.gregs[15],
+        uc->uc_mcontext.gregs[3],
+        uc->uc_mcontext.gregs[2],
+        uc->uc_mcontext.gregs[1],
+        uc->uc_mcontext.gregs[0]
+    );
+    logStackContent((void**)uc->uc_mcontext.gregs[7]);
+    #elif defined(__X86_64__) || defined(__x86_64__)
+    /* Linux AMD64 */
+    redisLog(REDIS_WARNING,
+    "\n"
+    "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
+    "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
+    "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
+    "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
+    "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
+        uc->uc_mcontext.gregs[13],
+        uc->uc_mcontext.gregs[11],
+        uc->uc_mcontext.gregs[14],
+        uc->uc_mcontext.gregs[12],
+        uc->uc_mcontext.gregs[8],
+        uc->uc_mcontext.gregs[9],
+        uc->uc_mcontext.gregs[10],
+        uc->uc_mcontext.gregs[15],
+        uc->uc_mcontext.gregs[0],
+        uc->uc_mcontext.gregs[1],
+        uc->uc_mcontext.gregs[2],
+        uc->uc_mcontext.gregs[3],
+        uc->uc_mcontext.gregs[4],
+        uc->uc_mcontext.gregs[5],
+        uc->uc_mcontext.gregs[6],
+        uc->uc_mcontext.gregs[7],
+        uc->uc_mcontext.gregs[16],
+        uc->uc_mcontext.gregs[17],
+        uc->uc_mcontext.gregs[18]
+    );
+    logStackContent((void**)uc->uc_mcontext.gregs[15]);
+    #endif
+#else
+    redisLog(REDIS_WARNING,
+        "  Dumping of registers not supported for this OS/arch");
 #endif
 }
+
+/* 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 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)
+        trace[1] = getMcontextEip(uc);
+
+    /* 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
+ * 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 */
+    redisLog(REDIS_WARNING, "--- STACK TRACE");
+    logStackTrace(uc);
+
+    /* Log INFO and CLIENT LIST */
+    redisLog(REDIS_WARNING, "--- INFO OUTPUT");
+    infostring = genRedisInfoString("all");
+    infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
+        dictGetHashFunctionSeed());
+    redisLogRaw(REDIS_WARNING, infostring);
+    redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
+    clients = getAllClientsInfoString();
+    redisLogRaw(REDIS_WARNING, clients);
+    sdsfree(infostring);
+    sdsfree(clients);
+
+    /* 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"
+"       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);
+
+    /* 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);
+    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) {
+#ifdef HAVE_BACKTRACE
+    ucontext_t *uc = (ucontext_t*) secret;
+#endif
+    REDIS_NOTUSED(info);
+    REDIS_NOTUSED(sig);
+
+    redisLogFromHandler(REDIS_WARNING,"\n--- WATCHDOG TIMER EXPIRED ---");
+#ifdef HAVE_BACKTRACE
+    logStackTrace(uc);
+#else
+    redisLogFromHandler(REDIS_WARNING,"Sorry: no support for backtrace().");
+#endif
+    redisLogFromHandler(REDIS_WARNING,"--------\n");
+}
+
+/* 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;
+}