Merge branch 'watchdog' into unstable

diff --combined src/redis.c
index 79cf2b83b2e2fb604338297cb0bec7ad57397438,88fb2fd8d3b087980291e74f192f7b34f0eb9e67..5ee44a31932165257153f24974e6c0bdde086eea
--- 1/src/redis.c
--- 2/src/redis.c
+++ b/src/redis.c
@@@ -612,7 -612,7 +612,7 @@@ void activeExpireCycle(void) 
  }
  
  void updateLRUClock(void) {
 -    server.lruclock = (time(NULL)/REDIS_LRU_CLOCK_RESOLUTION) &
 +    server.lruclock = (server.unixtime/REDIS_LRU_CLOCK_RESOLUTION) &
                                                  REDIS_LRU_CLOCK_MAX;
  }
  
@@@ -726,6 -726,10 +726,10 @@@ int serverCron(struct aeEventLoop *even
      REDIS_NOTUSED(id);
      REDIS_NOTUSED(clientData);
  
+     /* Software watchdog: deliver the SIGALRM that will reach the signal
+      * handler if we don't return here fast enough. */
+     if (server.watchdog_period) watchdogScheduleSignal(server.watchdog_period);
+ 
      /* We take a cached value of the unix time in the global state because
       * with virtual memory and aging there is to store the current time
       * in objects at every object access, and accuracy is not needed.
@@@ -821,13 -825,15 +825,13 @@@
              updateDictResizePolicy();
          }
      } else {
 -         time_t now = time(NULL);
 -
          /* If there is not a background saving/rewrite in progress check if
           * we have to save/rewrite now */
           for (j = 0; j < server.saveparamslen; j++) {
              struct saveparam *sp = server.saveparams+j;
  
              if (server.dirty >= sp->changes &&
 -                now-server.lastsave > sp->seconds) {
 +                server.unixtime-server.lastsave > sp->seconds) {
                  redisLog(REDIS_NOTICE,"%d changes in %d seconds. Saving...",
                      sp->changes, sp->seconds);
                  rdbSaveBackground(server.rdb_filename);
@@@ -1084,11 -1090,12 +1088,12 @@@ void initServerConfig() 
      server.slowlog_log_slower_than = REDIS_SLOWLOG_LOG_SLOWER_THAN;
      server.slowlog_max_len = REDIS_SLOWLOG_MAX_LEN;
  
-     /* Assert */
+     /* Debugging */
      server.assert_failed = "<no assertion failed>";
      server.assert_file = "<no file>";
      server.assert_line = 0;
      server.bug_report_start = 0;
+     server.watchdog_period = 0;
  }
  
  /* This function will try to raise the max number of open files accordingly to
@@@ -1681,7 -1688,7 +1686,7 @@@ void bytesToHuman(char *s, unsigned lon
   * on memory corruption problems. */
  sds genRedisInfoString(char *section) {
      sds info = sdsempty();
 -    time_t uptime = time(NULL)-server.stat_starttime;
 +    time_t uptime = server.unixtime-server.stat_starttime;
      int j, numcommands;
      struct rusage self_ru, c_ru;
      unsigned long lol, bib;
@@@ -1820,7 -1827,7 +1825,7 @@@
              perc = ((double)server.loading_loaded_bytes /
                     server.loading_total_bytes) * 100;
  
 -            elapsed = time(NULL)-server.loading_start_time;
 +            elapsed = server.unixtime-server.loading_start_time;
              if (elapsed == 0) {
                  eta = 1; /* A fake 1 second figure if we don't have
                              enough info */
@@@ -1891,7 -1898,7 +1896,7 @@@
                  (server.repl_state == REDIS_REPL_CONNECTED) ?
                      "up" : "down",
                  server.master ?
 -                ((int)(time(NULL)-server.master->lastinteraction)) : -1,
 +                ((int)(server.unixtime-server.master->lastinteraction)) : -1,
                  server.repl_state == REDIS_REPL_TRANSFER
              );
  
@@@ -1900,14 -1907,14 +1905,14 @@@
                      "master_sync_left_bytes:%ld\r\n"
                      "master_sync_last_io_seconds_ago:%d\r\n"
                      ,(long)server.repl_transfer_left,
 -                    (int)(time(NULL)-server.repl_transfer_lastio)
 +                    (int)(server.unixtime-server.repl_transfer_lastio)
                  );
              }
  
              if (server.repl_state != REDIS_REPL_CONNECTED) {
                  info = sdscatprintf(info,
                      "master_link_down_since_seconds:%ld\r\n",
 -                    (long)time(NULL)-server.repl_down_since);
 +                    (long)server.unixtime-server.repl_down_since);
              }
          }
          info = sdscatprintf(info,

diff --combined src/redis.h
index a1468a3b660673dff12c54fd0ae4d49dd8111e6f,20e0ea981d67ac5b388dcee4d3533d977979a48d..c5812f0af03a8d5abe3ff505f51a120df42926b3
--- 1/src/redis.h
--- 2/src/redis.h
+++ b/src/redis.h
@@@ -722,6 -722,7 +722,7 @@@ struct redisServer 
      char *assert_file;
      int assert_line;
      int bug_report_start; /* True if bug report header was already logged. */
+     int watchdog_period;  /* Software watchdog period in ms. 0 = off */
  };
  
  typedef struct pubsubPattern {
@@@ -817,7 -818,7 +818,7 @@@ extern dictType zsetDictType
  extern dictType clusterNodesDictType;
  extern dictType dbDictType;
  extern double R_Zero, R_PosInf, R_NegInf, R_Nan;
 -dictType hashDictType;
 +extern dictType hashDictType;
  
  /*-----------------------------------------------------------------------------
   * Functions prototypes
@@@ -1255,4 -1256,7 +1256,7 @@@ void bugReportStart(void)
  void redisLogObjectDebugInfo(robj *o);
  void sigsegvHandler(int sig, siginfo_t *info, void *secret);
  sds genRedisInfoString(char *section);
+ void enableWatchdog(int period);
+ void disableWatchdog(void);
+ void watchdogScheduleSignal(int period);
  #endif