2004-12-21 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* {ChangeLog,watchquagga.c,Makefile.am}: Created.

3 files changed, 1360 insertions, 0 deletions

diff --git a/watchquagga/ChangeLog b/watchquagga/ChangeLog
new file mode 100644
index 00000000..b8974825
--- /dev/null
+++ b/watchquagga/ChangeLog
@@ -0,0 +1,3 @@
+2004-12-21 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+
+	* {ChangeLog,watchquagga.c,Makefile.am}: Created.
diff --git a/watchquagga/Makefile.am b/watchquagga/Makefile.am
new file mode 100644
index 00000000..e422535a
--- /dev/null
+++ b/watchquagga/Makefile.am
@@ -0,0 +1,9 @@
+## Process this file with Automake to create Makefile.in
+
+INCLUDES = @INCLUDES@ -I$(top_srcdir) -I$(top_srcdir)/lib
+DEFS = @DEFS@ -DSTATEDIR=\"$(localstatedir)/\"
+
+sbin_PROGRAMS = watchquagga
+
+watchquagga_SOURCES = watchquagga.c
+watchquagga_LDADD = ../lib/libzebra.la @LIBCAP@
diff --git a/watchquagga/watchquagga.c b/watchquagga/watchquagga.c
new file mode 100644
index 00000000..c9b2cad8
--- /dev/null
+++ b/watchquagga/watchquagga.c
@@ -0,0 +1,1348 @@
+/*
+    $Id: watchquagga.c,v 1.1 2004/12/22 02:56:59 ajs Exp $
+
+    Monitor status of quagga daemons and restart if necessary.
+
+    Copyright (C) 2004  Andrew J. Schorr
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/* System headers: */
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+
+/* Quagga headers: */
+#include <thread.h>
+#include <log.h>
+#include <sigevent.h>
+#include <version.h>
+
+#ifndef MIN
+#define MIN(X,Y) (((X) <= (Y)) ? (X) : (Y))
+#endif
+
+/* Macros to help randomize timers. */
+#define JITTER(X) ((random() % ((X)+1))-((X)/2))
+#define FUZZY(X) ((X)+JITTER((X)/20))
+
+#define DEFAULT_PERIOD		5
+#define DEFAULT_TIMEOUT		10
+#define DEFAULT_RESTART_TIMEOUT	20
+#define DEFAULT_LOGLEVEL	LOG_INFO
+#define DEFAULT_MIN_RESTART	60
+#define DEFAULT_MAX_RESTART	600
+#define DEFAULT_PIDFILE		STATEDIR "/watchquagga.pid"
+
+#define PING_TOKEN	"PING"
+
+/* Needs to be global, referenced somewhere inside libzebra. */
+struct thread_master *master;
+
+typedef enum
+{
+  MODE_MONITOR = 0,
+  MODE_GLOBAL_RESTART,
+  MODE_SEPARATE_RESTART,
+  MODE_PHASED_ZEBRA_RESTART,
+  MODE_PHASED_ALL_RESTART
+} watch_mode_t;
+
+static const char *mode_str[] =
+{
+  "monitor",
+  "global restart",
+  "individual daemon restart",
+  "phased zebra restart",
+  "phased global restart for any failure",
+};
+
+typedef enum
+{
+  PHASE_NONE = 0,
+  PHASE_STOPS_PENDING,
+  PHASE_WAITING_DOWN,
+  PHASE_ZEBRA_RESTART_PENDING,
+  PHASE_WAITING_ZEBRA_UP
+} restart_phase_t;
+
+static const char *phase_str[] =
+{
+  "None",
+  "Stop jobs running",
+  "Waiting for other daemons to come down",
+  "Zebra restart job running",
+  "Waiting for zebra to come up",
+  "Start jobs running",
+};
+
+#define PHASE_TIMEOUT (3*gs.restart_timeout)
+
+static struct global_state {
+  watch_mode_t mode;
+  restart_phase_t phase;
+  struct thread *t_phase_hanging;
+  const char *vtydir;
+  long period;
+  long timeout;
+  long restart_timeout;
+  long min_restart_interval;
+  long max_restart_interval;
+  int do_ping;
+  struct daemon *daemons;
+  const char *restart_command;
+  const char *start_command;
+  const char *stop_command;
+  struct restart_info
+    {
+      const char *name;
+      const char *what;
+      pid_t pid;
+      struct timeval time;
+      long interval;
+      struct thread *t_kill;
+      int kills;
+    } restart;
+  int unresponsive_restart;
+  int loglevel;
+  struct daemon *special;	/* points to zebra when doing phased restart */
+  int numdaemons;
+  int numpids;
+  int numdown;		/* # of daemons that are not UP or UNRESPONSIVE */
+} gs = {
+  .mode = MODE_MONITOR,
+  .phase = PHASE_NONE,
+  .vtydir = STATEDIR,
+  .period = 1000*DEFAULT_PERIOD,
+  .timeout = DEFAULT_TIMEOUT,
+  .restart_timeout = DEFAULT_RESTART_TIMEOUT,
+  .loglevel = DEFAULT_LOGLEVEL,
+  .min_restart_interval = DEFAULT_MIN_RESTART,
+  .max_restart_interval = DEFAULT_MAX_RESTART,
+  .do_ping = 1,
+  .restart.name = "all",
+};
+
+typedef enum
+{
+  DAEMON_INIT,
+  DAEMON_DOWN,
+  DAEMON_CONNECTING,
+  DAEMON_UP,
+  DAEMON_UNRESPONSIVE
+} daemon_state_t;
+
+#define IS_UP(DMN) \
+  (((DMN)->state == DAEMON_UP) || ((DMN)->state == DAEMON_UNRESPONSIVE))
+
+static const char *state_str[] =
+{
+  "Init",
+  "Down",
+  "Connecting",
+  "Up",
+  "Unresponsive",
+};
+
+struct daemon {
+  const char *name;
+  daemon_state_t state;
+  int fd;
+  struct timeval echo_sent;
+  u_int connect_tries;
+  struct thread *t_wakeup;
+  struct thread *t_read;
+  struct thread *t_write;
+  struct daemon *next;
+  struct restart_info restart;
+};
+
+static const struct option longopts[] = 
+{
+  { "daemon", no_argument, NULL, 'd'},
+  { "statedir", required_argument, NULL, 'S'},
+  { "no-echo", no_argument, NULL, 'e'},
+  { "loglevel", required_argument, NULL, 'l'},
+  { "interval", required_argument, NULL, 'i'},
+  { "timeout", required_argument, NULL, 't'},
+  { "restart-timeout", required_argument, NULL, 'T'},
+  { "restart", required_argument, NULL, 'r'},
+  { "start-command", required_argument, NULL, 's'},
+  { "kill-command", required_argument, NULL, 'k'},
+  { "restart-all", required_argument, NULL, 'R'},
+  { "all-restart", no_argument, NULL, 'a'},
+  { "always-all-restart", no_argument, NULL, 'A'},
+  { "unresponsive-restart", no_argument, NULL, 'z'},
+  { "min-restart-interval", required_argument, NULL, 'm'},
+  { "max-restart-interval", required_argument, NULL, 'M'},
+  { "pid-file", required_argument, NULL, 'p'},
+  { "help", no_argument, NULL, 'h'},
+  { "version", no_argument, NULL, 'v'},
+  { NULL, 0, NULL, 0 }
+};
+
+static int try_connect(struct daemon *dmn);
+static int wakeup_send_echo(struct thread *t_wakeup);
+static void try_restart(struct daemon *dmn);
+static void phase_check(void);
+
+static int
+usage(const char *progname, int status)
+{
+  if (status != 0)
+    fprintf(stderr, "Try `%s --help' for more information.\n", progname);
+  else
+    printf("Usage : %s [OPTION...] <daemon name> ...\n\n\
+Watchdog program to monitor status of quagga daemons and try to restart\n\
+them if they are down or unresponsive.  It determines whether a daemon is\n\
+up based on whether it can connect to the daemon's vty unix stream socket.\n\
+It then repeatedly sends echo commands over that socket to determine whether\n\
+the daemon is responsive.  If the daemon crashes, we will receive an EOF\n\
+on the socket connection and know immediately that the daemon is down.\n\n\
+The daemons to be monitored should be listed on the command line.\n\n\
+This program can run in one of 5 modes:\n\n\
+0. Mode: %s.\n\
+  Just monitor and report on status changes.  Example:\n\
+    %s -d zebra ospfd bgpd\n\n\
+1. Mode: %s.\n\
+  Whenever any daemon hangs or crashes, use the given command to restart\n\
+  them all.  Example:\n\
+    %s -dz \\\n\
+      -R '/sbin/service zebra restart; /sbin/service ospfd restart' \\\n\
+      zebra ospfd\n\n\
+2. Mode: %s.\n\
+  When any single daemon hangs or crashes, restart only the daemon that's\n\
+  in trouble using the supplied restart command.  Example:\n\
+    %s -dz -r '/sbin/service %%s restart' zebra ospfd bgpd\n\n\
+3. Mode: %s.\n\
+  The same as the previous mode, except that there is special treatment when\n\
+  the zebra daemon is in trouble.  In that case, a phased restart approach\n\
+  is used: 1. stop all other daemons; 2. restart zebra; 3. start the other\n\
+  daemons.  Example:\n\
+    %s -adz -r '/sbin/service %%s restart' \\\n\
+      -s '/sbin/service %%s start' \\\n\
+      -k '/sbin/service %%s stop' zebra ospfd bgpd\n\n\
+4. Mode: %s.\n\
+  This is the same as the previous mode, except that the phased restart\n\
+  procedure is used whenever any of the daemons hangs or crashes.  Example:\n\
+    %s -Adz -r '/sbin/service %%s restart' \\\n\
+      -s '/sbin/service %%s start' \\\n\
+      -k '/sbin/service %%s stop' zebra ospfd bgpd\n\n\
+As of this writing, it is believed that mode 2 [%s]\n\
+is not safe, and mode 3 [%s] may not be safe with some of the\n\
+routing daemons.\n\n\
+In order to avoid attempting to restart the daemons in a fast loop,\n\
+the -m and -M options allow you to control the minimum delay between\n\
+restart commands.  The minimum restart delay is recalculated each time\n\
+a restart is attempted: if the time since the last restart attempt exceeds\n\
+twice the -M value, then the restart delay is set to the -m value.\n\
+Otherwise, the interval is doubled (but capped at the -M value).\n\n\
+Options:\n\
+-d, --daemon	Run in daemon mode.  In this mode, error messages are sent\n\
+		to syslog instead of stdout.\n\
+-S, --statedir	Set the vty socket directory (default is %s)\n\
+-e, --no-echo	Do not ping the daemons to test responsiveness (this\n\
+		option is necessary if the daemons do not support the\n\
+		echo command)\n\
+-l, --loglevel	Set the logging level (default is %d).\n\
+		The value should range from %d (LOG_EMERG) to %d (LOG_DEBUG),\n\
+		but it can be set higher than %d if extra-verbose debugging\n\
+		messages are desired.\n\
+-m, --min-restart-interval\n\
+		Set the minimum seconds to wait between invocations of daemon\n\
+		restart commands (default is %d).\n\
+-M, --max-restart-interval\n\
+		Set the maximum seconds to wait between invocations of daemon\n\
+		restart commands (default is %d).\n\
+-i, --interval	Set the status polling interval in seconds (default is %d)\n\
+-t, --timeout	Set the unresponsiveness timeout in seconds (default is %d)\n\
+-T, --restart-timeout\n\
+		Set the restart (kill) timeout in seconds (default is %d).\n\
+		If any background jobs are still running after this much\n\
+		time has elapsed, they will be killed.\n\
+-r, --restart	Supply a Bourne shell command to use to restart a single\n\
+		daemon.  The command string should include '%%s' where the\n\
+		name of the daemon should be substituted.\n\
+		Note that -r and -R are incompatible.\n\
+-s, --start-command\n\
+		Supply a Bourne shell to command to use to start a single\n\
+		daemon.  The command string should include '%%s' where the\n\
+		name of the daemon should be substituted.\n\
+-k, --kill-command\n\
+		Supply a Bourne shell to command to use to stop a single\n\
+		daemon.  The command string should include '%%s' where the\n\
+		name of the daemon should be substituted.\n\
+-R, --restart-all\n\
+		When one or more daemons is down, try to restart everything\n\
+		using the Bourne shell command supplied as the argument.\n\
+		Note that -r and -R are incompatible.\n\
+-z, --unresponsive-restart\n\
+		When a daemon is unresponsive, treat it as being down for\n\
+		restart purposes.\n\
+-a, --all-restart\n\
+		When zebra hangs or crashes, restart all daemons using\n\
+		this phased approach: 1. stop all other daemons; 2. restart\n\
+		zebra; 3. start other daemons.  Requires -r, -s, and -k.\n\
+-A, --always-all-restart\n\
+		When any daemon (not just zebra) hangs or crashes, use the\n\
+		same phased restart mechanism described above for -a.\n\
+		Requires -r, -s, and -k.\n\
+-p, --pid-file	Set process identifier file name\n\
+		(default is %s).\n\
+-v, --version	Print program version\n\
+-h, --help	Display this help and exit\n\
+", progname,mode_str[0],progname,mode_str[1],progname,mode_str[2],
+progname,mode_str[3],progname,mode_str[4],progname,mode_str[2],mode_str[3],
+STATEDIR,DEFAULT_LOGLEVEL,LOG_EMERG,LOG_DEBUG,LOG_DEBUG,
+DEFAULT_MIN_RESTART,DEFAULT_MAX_RESTART,
+DEFAULT_PERIOD,DEFAULT_TIMEOUT,DEFAULT_RESTART_TIMEOUT,DEFAULT_PIDFILE);
+
+  return status;
+}
+
+static pid_t
+run_background(const char *shell_cmd)
+{
+  pid_t child;
+
+  switch (child = fork())
+    {
+    case -1:
+      zlog_err("fork failed, cannot run command [%s]: %s",
+	       shell_cmd,safe_strerror(errno));
+      return -1;
+    case 0:
+      /* Child process. */
+      /* Use separate process group so child processes can be killed easily. */
+      if (setpgid(0,0) < 0)
+        zlog_warn("warning: setpgid(0,0) failed: %s",safe_strerror(errno));
+      {
+        const char *argv[4] = { "sh", "-c", shell_cmd, NULL};
+	execv("/bin/sh",(char *const *)argv);
+	zlog_err("execv(/bin/sh -c '%s') failed: %s",
+		 shell_cmd,safe_strerror(errno));
+	_exit(127);
+      }
+    default:
+      /* Parent process: we will reap the child later. */
+      zlog_err("Forked background command [pid %d]: %s",child,shell_cmd);
+      return child;
+    }
+}
+
+static struct timeval *
+time_elapsed(struct timeval *result, const struct timeval *start_time)
+{
+  gettimeofday(result,NULL);
+  result->tv_sec -= start_time->tv_sec;
+  result->tv_usec -= start_time->tv_usec;
+  while (result->tv_usec < 0)
+    {
+      result->tv_usec += 1000000L;
+      result->tv_sec--;
+    }
+  return result;
+}
+
+static int
+restart_kill(struct thread *t_kill)
+{
+  struct restart_info *restart = THREAD_ARG(t_kill);
+  struct timeval delay;
+
+  time_elapsed(&delay,&restart->time);
+  zlog_warn("Warning: %s %s child process %d still running after "
+	    "%ld seconds, sending signal %d",
+	    restart->what,restart->name,restart->pid,delay.tv_sec,
+	    (restart->kills ? SIGKILL : SIGTERM));
+  kill(-restart->pid,(restart->kills ? SIGKILL : SIGTERM));
+  restart->kills++;
+  restart->t_kill = thread_add_timer(master,restart_kill,restart,
+				     gs.restart_timeout);
+  return 0;
+}
+
+static struct restart_info *
+find_child(pid_t child)
+{
+  if (gs.mode == MODE_GLOBAL_RESTART)
+    {
+      if (gs.restart.pid == child)
+        return &gs.restart;
+    }
+  else
+    {
+      struct daemon *dmn;
+      for (dmn = gs.daemons; dmn; dmn = dmn->next)
+        {
+	  if (dmn->restart.pid == child)
+	    return &dmn->restart;
+        }
+    }
+  return NULL;
+}
+
+static void
+sigchild(void)
+{
+  pid_t child;
+  int status;
+  const char *name;
+  const char *what;
+  struct restart_info *restart;
+
+  switch (child = waitpid(-1,&status,WNOHANG)) 
+    {
+    case -1:
+      zlog_err("waitpid failed: %s",safe_strerror(errno));
+      return;
+    case 0:
+      zlog_warn("SIGCHLD received, but waitpid did not reap a child");
+      return;
+    }
+
+  if ((restart = find_child(child)) != NULL)
+    {
+      name = restart->name;
+      what = restart->what;
+      restart->pid = 0;
+      gs.numpids--;
+      thread_cancel(restart->t_kill);
+      restart->t_kill = NULL;
+      /* Update restart time to reflect the time the command completed. */
+      gettimeofday(&restart->time,NULL);
+    }
+  else
+    {
+      zlog_err("waitpid returned status for an unknown child process %d",
+	       child);
+      name = "(unknown)";
+      what = "background";
+    }
+  if (WIFSTOPPED(status))
+      zlog_warn("warning: %s %s process %d is stopped",
+		what,name,child);
+  else if (WIFSIGNALED(status))
+    zlog_warn("%s %s process %d terminated due to signal %d",
+	      what,name,child,WTERMSIG(status));
+  else if (WIFEXITED(status))
+    {
+      if (WEXITSTATUS(status) != 0)
+	zlog_warn("%s %s process %d exited with non-zero status %d",
+		  what,name,child,WEXITSTATUS(status));
+      else
+	zlog_debug("%s %s process %d exited normally",what,name,child);
+    }
+  else
+    zlog_err("cannot interpret %s %s process %d wait status 0x%x",
+	     what,name,child,status);
+  phase_check();
+}
+
+static int
+run_job(struct restart_info *restart, const char *cmdtype, const char *command,
+	int force, int update_interval)
+{
+  struct timeval delay;
+
+  if (gs.loglevel > LOG_DEBUG+1)
+    zlog_debug("attempting to %s %s",cmdtype,restart->name);
+
+  if (restart->pid)
+    {
+      if (gs.loglevel > LOG_DEBUG+1)
+        zlog_debug("cannot %s %s, previous pid %d still running",
+		   cmdtype,restart->name,restart->pid);
+      return -1;
+    }
+
+  if (!force &&
+      (time_elapsed(&delay,&restart->time)->tv_sec < restart->interval))
+    {
+      if (gs.loglevel > LOG_DEBUG+1)
+        zlog_debug("postponing %s %s: "
+		   "elapsed time %ld < retry interval %ld",
+		   cmdtype,restart->name,(long)delay.tv_sec,restart->interval);
+      return -1;
+    }
+
+  gettimeofday(&restart->time,NULL);
+  restart->kills = 0;
+  {
+    char cmd[strlen(command)+strlen(restart->name)+1];
+    snprintf(cmd,sizeof(cmd),command,restart->name);
+    if ((restart->pid = run_background(cmd)) > 0)
+      {
+	restart->t_kill = thread_add_timer(master,restart_kill,restart,
+					   gs.restart_timeout);
+	restart->what = cmdtype;
+	gs.numpids++;
+      }
+    else
+      restart->pid = 0;
+  }
+
+  /* Calculate the new restart interval. */
+  if (update_interval)
+    {
+      if (delay.tv_sec > 2*gs.max_restart_interval)
+	restart->interval = gs.min_restart_interval;
+      else if ((restart->interval *= 2) > gs.max_restart_interval)
+	restart->interval = gs.max_restart_interval;
+      if (gs.loglevel > LOG_DEBUG+1)
+	zlog_debug("restart %s interval is now %ld",
+		   restart->name,restart->interval);
+    }
+  return restart->pid;
+}
+
+#define SET_READ_HANDLER(DMN) \
+  (DMN)->t_read = thread_add_read(master,handle_read,(DMN),(DMN)->fd)
+
+#define SET_WAKEUP_DOWN(DMN)	\
+  (DMN)->t_wakeup = thread_add_timer_msec(master,wakeup_down,(DMN),	\
+    					  FUZZY(gs.period))
+
+#define SET_WAKEUP_UNRESPONSIVE(DMN)	\
+  (DMN)->t_wakeup = thread_add_timer_msec(master,wakeup_unresponsive,(DMN), \
+    					  FUZZY(gs.period))
+
+#define SET_WAKEUP_ECHO(DMN) \
+  (DMN)->t_wakeup = thread_add_timer_msec(master,wakeup_send_echo,(DMN), \
+					  FUZZY(gs.period))
+
+static int
+wakeup_down(struct thread *t_wakeup)
+{
+  struct daemon *dmn = THREAD_ARG(t_wakeup);
+
+  dmn->t_wakeup = NULL;
+  if (try_connect(dmn) < 0)
+    SET_WAKEUP_DOWN(dmn);
+  if ((dmn->connect_tries > 1) && (dmn->state != DAEMON_UP))
+    try_restart(dmn);
+  return 0;
+}
+
+static int
+wakeup_init(struct thread *t_wakeup)
+{
+  struct daemon *dmn = THREAD_ARG(t_wakeup);
+
+  dmn->t_wakeup = NULL;
+  if (try_connect(dmn) < 0)
+    {
+      SET_WAKEUP_DOWN(dmn);
+      zlog_err("%s state -> down : initial connection attempt failed",
+	       dmn->name);
+      dmn->state = DAEMON_DOWN;
+    }
+  return 0;
+}
+
+static void
+daemon_down(struct daemon *dmn, const char *why)
+{
+  if (IS_UP(dmn) || (dmn->state == DAEMON_INIT))
+    zlog_err("%s state -> down : %s",dmn->name,why);
+  else if (gs.loglevel > LOG_DEBUG)
+    zlog_debug("%s still down : %s",dmn->name,why);
+  if (IS_UP(dmn))
+    gs.numdown++;
+  dmn->state = DAEMON_DOWN;
+  if (dmn->fd >= 0)
+    {
+      close(dmn->fd);
+      dmn->fd = -1;
+    }
+  THREAD_OFF(dmn->t_read);
+  THREAD_OFF(dmn->t_write);
+  THREAD_OFF(dmn->t_wakeup);
+  if (try_connect(dmn) < 0)
+    SET_WAKEUP_DOWN(dmn);
+  phase_check();
+}
+
+static int
+handle_read(struct thread *t_read)
+{
+  struct daemon *dmn = THREAD_ARG(t_read);
+  static const char resp[sizeof(PING_TOKEN)+4] = PING_TOKEN "\n";
+  char buf[sizeof(resp)+100];
+  ssize_t rc;
+  struct timeval delay;
+
+  dmn->t_read = NULL;
+  if ((rc = read(dmn->fd,buf,sizeof(buf))) < 0)
+    {
+      char why[100];
+
+      if ((errno == EINTR) || (errno == EAGAIN))
+	{
+	  /* Pretend it never happened. */
+	  SET_READ_HANDLER(dmn);
+	  return 0;
+	}
+      snprintf(why,sizeof(why),"unexpected read error: %s",
+	       safe_strerror(errno));
+      daemon_down(dmn,why);
+      return 0;
+    }
+  if (rc == 0)
+    {
+      daemon_down(dmn,"read returned EOF");
+      return 0;
+    }
+  if (!dmn->echo_sent.tv_sec)
+    {
+      char why[sizeof(buf)+100];
+      snprintf(why,sizeof(why),"unexpected read returns %zd bytes: %.*s",
+	       rc,rc,buf);
+      daemon_down(dmn,why);
+      return 0;
+    }
+
+  /* We are expecting an echo response: is there any chance that the
+     response would not be returned entirely in the first read?  That
+     seems inconceivable... */
+  if ((rc != sizeof(resp)) || memcmp(buf,resp,sizeof(resp)))
+    {
+      char why[100+sizeof(buf)];
+      snprintf(why,sizeof(why),"read returned bad echo response of %zd bytes "
+			       "(expecting %zu): %.*s",
+	       rc,sizeof(resp),rc,buf);
+      daemon_down(dmn,why);
+      return 0;
+    }
+
+  time_elapsed(&delay,&dmn->echo_sent);
+  dmn->echo_sent.tv_sec = 0;
+  if (dmn->state == DAEMON_UNRESPONSIVE)
+    {
+      if (delay.tv_sec < gs.timeout)
+	{
+	  dmn->state = DAEMON_UP;
+	  zlog_warn("%s state -> up : echo response received after %ld.%06ld "
+		    "seconds", dmn->name,delay.tv_sec,delay.tv_usec);
+	}
+      else
+	zlog_warn("%s: slow echo response finally received after %ld.%06ld "
+		  "seconds", dmn->name,delay.tv_sec,delay.tv_usec);
+    }
+  else if (gs.loglevel > LOG_DEBUG+1)
+    zlog_debug("%s: echo response received after %ld.%06ld seconds",
+	       dmn->name,delay.tv_sec,delay.tv_usec);
+
+  SET_READ_HANDLER(dmn);
+  if (dmn->t_wakeup)
+    thread_cancel(dmn->t_wakeup);
+  SET_WAKEUP_ECHO(dmn);
+
+  return 0;
+}
+
+static void
+daemon_up(struct daemon *dmn, const char *why)
+{
+  dmn->state = DAEMON_UP;
+  gs.numdown--;
+  dmn->connect_tries = 0;
+  zlog_notice("%s state -> up : %s",dmn->name,why);
+  if (gs.do_ping)
+    SET_WAKEUP_ECHO(dmn);
+  phase_check();
+}
+
+static int
+check_connect(struct thread *t_write)
+{
+  struct daemon *dmn = THREAD_ARG(t_write);
+  int sockerr;
+  socklen_t reslen = sizeof(sockerr);
+
+  dmn->t_write = NULL;
+  if (getsockopt(dmn->fd,SOL_SOCKET,SO_ERROR,(char *)&sockerr,&reslen) < 0)
+    {
+      zlog_warn("%s: check_connect: getsockopt failed: %s",
+	        dmn->name,safe_strerror(errno));
+      daemon_down(dmn,"getsockopt failed checking connection success");
+      return 0;
+    }
+  if ((reslen == sizeof(sockerr)) && sockerr)
+    {
+      char why[100];
+      snprintf(why,sizeof(why),
+	       "getsockopt reports that connection attempt failed: %s",
+	       safe_strerror(sockerr));
+      daemon_down(dmn,why);
+      return 0;
+    }
+
+  daemon_up(dmn,"delayed connect succeeded");
+  return 0;
+}
+
+static int
+wakeup_connect_hanging(struct thread *t_wakeup)
+{
+  struct daemon *dmn = THREAD_ARG(t_wakeup);
+  char why[100];
+
+  dmn->t_wakeup = NULL;
+  snprintf(why,sizeof(why),"connection attempt timed out after %ld seconds",
+	   gs.timeout);
+  daemon_down(dmn,why);
+  return 0;
+}
+
+/* Making connection to protocol daemon. */
+static int
+try_connect(struct daemon *dmn)
+{
+  int sock;
+  struct sockaddr_un addr;
+  socklen_t len;
+  int flags;
+
+  if (gs.loglevel > LOG_DEBUG+1)
+    zlog_debug("%s: attempting to connect",dmn->name);
+  dmn->connect_tries++;
+
+  memset (&addr, 0, sizeof (struct sockaddr_un));
+  addr.sun_family = AF_UNIX;
+  snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s.vty",
+	   gs.vtydir,dmn->name);
+#ifdef HAVE_SUN_LEN
+  len = addr.sun_len = SUN_LEN(&addr);
+#else
+  len = sizeof (addr.sun_family) + strlen (addr.sun_path);
+#endif /* HAVE_SUN_LEN */
+
+  /* Quick check to see if we might succeed before we go to the trouble
+     of creating a socket. */
+  if (access(addr.sun_path, W_OK) < 0)
+    {
+      if (errno != ENOENT)
+        zlog_err("%s: access to socket %s denied: %s",
+		dmn->name,addr.sun_path,safe_strerror(errno));
+      return -1;
+    }
+
+  if ((sock = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
+    {
+      zlog_err("%s(%s): cannot make socket: %s",
+	       __func__,addr.sun_path, safe_strerror(errno));
+      return -1;
+    }
+
+  /* Set non-blocking. */
+  if ((flags = fcntl(sock, F_GETFL, 0)) < 0)
+    {
+      zlog_err("%s(%s): fcntl(F_GETFL) failed: %s",
+	       __func__,addr.sun_path, safe_strerror(errno));
+      close(sock);
+      return -1;
+    }
+  if (fcntl(sock, F_SETFL, (flags|O_NONBLOCK)) < 0)
+    {
+      zlog_err("%s(%s): fcntl(F_SETFL,O_NONBLOCK) failed: %s",
+	       __func__,addr.sun_path, safe_strerror(errno));
+      close(sock);
+      return -1;
+    }
+
+  if (connect (sock, (struct sockaddr *) &addr, len) < 0)
+    {
+      if ((errno != EINPROGRESS) && (errno != EWOULDBLOCK))
+	{
+	  if (gs.loglevel > LOG_DEBUG)
+	    zlog_debug("%s(%s): connect failed: %s",
+		       __func__,addr.sun_path, safe_strerror(errno));
+	  close (sock);
+	  return -1;
+	}
+      if (gs.loglevel > LOG_DEBUG)
+	zlog_debug("%s: connection in progress",dmn->name);
+      dmn->state = DAEMON_CONNECTING;
+      dmn->fd = sock;
+      dmn->t_write = thread_add_write(master,check_connect,dmn,dmn->fd);
+      dmn->t_wakeup = thread_add_timer(master,wakeup_connect_hanging,dmn,
+				       gs.timeout);
+      SET_READ_HANDLER(dmn);
+      return 0;
+    }
+
+  dmn->fd = sock;
+  SET_READ_HANDLER(dmn);
+  daemon_up(dmn,"connect succeeded");
+  return 1;
+}
+
+static int
+phase_hanging(struct thread *t_hanging)
+{
+  gs.t_phase_hanging = NULL;
+  zlog_err("Phase [%s] hanging for %ld seconds, aborting phased restart",
+           phase_str[gs.phase],PHASE_TIMEOUT);
+  gs.phase = PHASE_NONE;
+  return 0;
+}
+
+static void
+set_phase(restart_phase_t new_phase)
+{
+  gs.phase = new_phase;
+  if (gs.t_phase_hanging)
+    thread_cancel(gs.t_phase_hanging);
+  gs.t_phase_hanging = thread_add_timer(master,phase_hanging,NULL,
+  					PHASE_TIMEOUT);
+}
+
+static void
+phase_check(void)
+{
+  switch (gs.phase)
+    {
+    case PHASE_NONE:
+      break;
+    case PHASE_STOPS_PENDING:
+      if (gs.numpids)
+	break;
+      zlog_info("Phased restart: all routing daemon stop jobs have completed.");
+      set_phase(PHASE_WAITING_DOWN);
+      /*FALLTHRU*/
+    case PHASE_WAITING_DOWN:
+      if (gs.numdown+IS_UP(gs.special) < gs.numdaemons)
+        break;
+      zlog_info("Phased restart: all routing daemons now down.");
+      run_job(&gs.special->restart,"restart",gs.restart_command,1,1);
+      set_phase(PHASE_ZEBRA_RESTART_PENDING);
+      /*FALLTHRU*/
+    case PHASE_ZEBRA_RESTART_PENDING:
+      if (gs.special->restart.pid)
+	break;
+      zlog_info("Phased restart: %s restart job completed.",gs.special->name);
+      set_phase(PHASE_WAITING_ZEBRA_UP);
+      /*FALLTHRU*/
+    case PHASE_WAITING_ZEBRA_UP:
+      if (!IS_UP(gs.special))
+        break;
+      zlog_info("Phased restart: %s is now up.",gs.special->name);
+      {
+        struct daemon *dmn;
+	for (dmn = gs.daemons; dmn; dmn = dmn->next)
+	  {
+	    if (dmn != gs.special)
+	      run_job(&dmn->restart,"start",gs.start_command,1,1);
+	  }
+      }
+      gs.phase = PHASE_NONE;
+      THREAD_OFF(gs.t_phase_hanging);
+      zlog_notice("Phased global restart has completed.");
+      break;
+    }
+}
+
+static void
+try_restart(struct daemon *dmn)
+{
+  switch (gs.mode)
+  {
+  case MODE_MONITOR:
+    return;
+  case MODE_GLOBAL_RESTART:
+    run_job(&gs.restart,"restart",gs.restart_command,0,1);
+    break;
+  case MODE_SEPARATE_RESTART:
+    run_job(&dmn->restart,"restart",gs.restart_command,0,1);
+    break;
+  case MODE_PHASED_ZEBRA_RESTART:
+    if (dmn != gs.special)
+      {
+        if ((gs.special->state == DAEMON_UP) && (gs.phase == PHASE_NONE))
+	  run_job(&dmn->restart,"restart",gs.restart_command,0,1);
+	else
+	  zlog_debug("%s: postponing restart attempt because master %s daemon "
+		     "not up [%s], or phased restart in progress",
+		     dmn->name,gs.special->name,state_str[gs.special->state]);
+	break;
+      }
+    /*FALLTHRU*/
+  case MODE_PHASED_ALL_RESTART:
+    if ((gs.phase != PHASE_NONE) || gs.numpids)
+      {
+	if (gs.loglevel > LOG_DEBUG+1)
+	  zlog_debug("postponing phased global restart: restart already in "
+		     "progress [%s], or outstanding child processes [%d]",
+		     phase_str[gs.phase],gs.numpids);
+        break;
+      }
+    /* Is it too soon for a restart? */
+    {
+      struct timeval delay;
+      if (time_elapsed(&delay,&gs.special->restart.time)->tv_sec <
+      	  gs.special->restart.interval)
+	{
+	  if (gs.loglevel > LOG_DEBUG+1)
+	    zlog_debug("postponing phased global restart: "
+		       "elapsed time %ld < retry interval %ld",
+		       (long)delay.tv_sec,gs.special->restart.interval);
+	  break;
+	}
+    }
+    zlog_info("Phased restart: stopping all routing daemons.");
+    /* First step: stop all other daemons. */
+    for (dmn = gs.daemons; dmn; dmn = dmn->next)
+      {
+        if (dmn != gs.special)
+	  run_job(&dmn->restart,"stop",gs.stop_command,1,0);
+      }
+    set_phase(PHASE_STOPS_PENDING);
+    break;
+  default:
+    zlog_err("error: unknown restart mode %d",gs.mode);
+    break;
+  }
+}
+
+static int
+wakeup_unresponsive(struct thread *t_wakeup)
+{
+  struct daemon *dmn = THREAD_ARG(t_wakeup);
+
+  dmn->t_wakeup = NULL;
+  if (dmn->state != DAEMON_UNRESPONSIVE)
+    zlog_err("%s: no longer unresponsive (now %s), "
+	     "wakeup should have been cancelled!",
+	     dmn->name,state_str[dmn->state]);
+  else
+    {
+      SET_WAKEUP_UNRESPONSIVE(dmn);
+      try_restart(dmn);
+    }
+  return 0;
+}
+
+static int
+wakeup_no_answer(struct thread *t_wakeup)
+{
+  struct daemon *dmn = THREAD_ARG(t_wakeup);
+
+  dmn->t_wakeup = NULL;
+  dmn->state = DAEMON_UNRESPONSIVE;
+  zlog_err("%s state -> unresponsive : no response yet to ping "
+	   "sent %ld seconds ago",dmn->name,gs.timeout);
+  if (gs.unresponsive_restart)
+    {
+      SET_WAKEUP_UNRESPONSIVE(dmn);
+      try_restart(dmn);
+    }
+  return 0;
+}
+
+static int
+wakeup_send_echo(struct thread *t_wakeup)
+{
+  static const char echocmd[] = "echo " PING_TOKEN;
+  ssize_t rc;
+  struct daemon *dmn = THREAD_ARG(t_wakeup);
+
+  dmn->t_wakeup = NULL;
+  if (((rc = write(dmn->fd,echocmd,sizeof(echocmd))) < 0) ||
+      ((size_t)rc != sizeof(echocmd)))
+    {
+      char why[100+sizeof(echocmd)];
+      snprintf(why,sizeof(why),"write '%s' returned %zd instead of %zu",
+               echocmd,rc,sizeof(echocmd));
+      daemon_down(dmn,why);
+    }
+  else
+    {
+      gettimeofday(&dmn->echo_sent,NULL);
+      dmn->t_wakeup = thread_add_timer(master,wakeup_no_answer,dmn,gs.timeout);
+    }
+  return 0;
+}
+
+static void
+sigint(void)
+{
+  zlog_notice("Terminating on signal");
+  exit(0);
+}
+
+static int
+valid_command(const char *cmd)
+{
+  char *p;
+
+  return ((p = strchr(cmd,'%')) != NULL) && (*(p+1) == 's') && !strchr(p+1,'%');
+}
+
+int
+main(int argc, char **argv)
+{
+  const char *progname;
+  int opt;
+  int daemon_mode = 0;
+  const char *pidfile = DEFAULT_PIDFILE;
+  const char *special = "zebra";
+  static struct quagga_signal_t my_signals[] =
+  {
+    {
+      .signal = SIGINT,
+      .handler = sigint,
+    },
+    {
+      .signal = SIGTERM,
+      .handler = sigint,
+    },
+    {
+      .signal = SIGCHLD,
+      .handler = sigchild,
+    },
+  };
+
+  if ((progname = strrchr (argv[0], '/')) != NULL)
+    progname++;
+  else
+    progname = argv[0];
+
+  while ((opt = getopt_long(argc, argv, "aAdek:l:m:M:i:p:r:R:S:s:t:T:zvh",
+			    longopts, 0)) != EOF)
+    {
+      switch (opt)
+        {
+	case 0:
+	  break;
+        case 'a':
+	  if ((gs.mode != MODE_MONITOR) && (gs.mode != MODE_SEPARATE_RESTART))
+	    {
+	      fputs("Ambiguous operating mode selected.\n",stderr);
+	      return usage(progname,1);
+	    }
+	  gs.mode = MODE_PHASED_ZEBRA_RESTART;
+	  break;
+        case 'A':
+	  if ((gs.mode != MODE_MONITOR) && (gs.mode != MODE_SEPARATE_RESTART))
+	    {
+	      fputs("Ambiguous operating mode selected.\n",stderr);
+	      return usage(progname,1);
+	    }
+	  gs.mode = MODE_PHASED_ALL_RESTART;
+	  break;
+        case 'd':
+	  daemon_mode = 1;
+	  break;
+        case 'e':
+	  gs.do_ping = 0;
+	  break;
+        case 'k':
+	  if (!valid_command(optarg))
+	  {
+	    fprintf(stderr,"Invalid kill command, must contain '%%s': %s\n",
+		    optarg);
+	    return usage(progname,1);
+	  }
+	  gs.stop_command = optarg;
+	  break;
+	case 'l':
+	  {
+	    char garbage[3];
+	    if ((sscanf(optarg,"%d%1s",&gs.loglevel,garbage) != 1) ||
+	        (gs.loglevel < LOG_EMERG))
+	      {
+	        fprintf(stderr,"Invalid loglevel argument: %s\n",optarg);
+		return usage(progname,1);
+	      }
+	  }
+	  break;
+	case 'm':
+	  {
+	    char garbage[3];
+	    if ((sscanf(optarg,"%ld%1s",
+	    		&gs.min_restart_interval,garbage) != 1) ||
+	        (gs.min_restart_interval < 0))
+	      {
+	        fprintf(stderr,"Invalid min_restart_interval argument: %s\n",
+		        optarg);
+		return usage(progname,1);
+	      }
+	  }
+	  break;
+	case 'M':
+	  {
+	    char garbage[3];
+	    if ((sscanf(optarg,"%ld%1s",
+	    		&gs.max_restart_interval,garbage) != 1) ||
+	        (gs.max_restart_interval < 0))
+	      {
+	        fprintf(stderr,"Invalid max_restart_interval argument: %s\n",
+		        optarg);
+		return usage(progname,1);
+	      }
+	  }
+	  break;
+	case 'i':
+	  {
+	    char garbage[3];
+	    int period;
+	    if ((sscanf(optarg,"%d%1s",&period,garbage) != 1) ||
+	        (gs.period < 1))
+	      {
+	        fprintf(stderr,"Invalid interval argument: %s\n",optarg);
+		return usage(progname,1);
+	      }
+	    gs.period = 1000*period;
+	  }
+	  break;
+        case 'p':
+	  pidfile = optarg;
+	  break;
+        case 'r':
+	  if ((gs.mode == MODE_GLOBAL_RESTART) ||
+	      (gs.mode == MODE_SEPARATE_RESTART))
+	    {
+	      fputs("Ambiguous operating mode selected.\n",stderr);
+	      return usage(progname,1);
+	    }
+	  if (!valid_command(optarg))
+	  {
+	    fprintf(stderr,
+		    "Invalid restart command, must contain '%%s': %s\n",
+		    optarg);
+	    return usage(progname,1);
+	  }
+	  gs.restart_command = optarg;
+	  if (gs.mode == MODE_MONITOR)
+	    gs.mode = MODE_SEPARATE_RESTART;
+	  break;
+        case 'R':
+	  if (gs.mode != MODE_MONITOR)
+	    {
+	      fputs("Ambiguous operating mode selected.\n",stderr);
+	      return usage(progname,1);
+	    }
+	  if (strchr(optarg,'%'))
+	    {
+	      fprintf(stderr,
+		      "Invalid restart-all arg, must not contain '%%s': %s\n",
+		      optarg);
+	      return usage(progname,1);
+	    }
+	  gs.restart_command = optarg;
+	  gs.mode = MODE_GLOBAL_RESTART;
+	  break;
+        case 's':
+	  if (!valid_command(optarg))
+	  {
+	    fprintf(stderr,"Invalid start command, must contain '%%s': %s\n",
+		    optarg);
+	    return usage(progname,1);
+	  }
+	  gs.start_command = optarg;
+	  break;
+	case 'S':
+	  gs.vtydir = optarg;
+	  break;
+	case 't':
+	  {
+	    char garbage[3];
+	    if ((sscanf(optarg,"%ld%1s",&gs.timeout,garbage) != 1) ||
+	        (gs.timeout < 1))
+	      {
+	        fprintf(stderr,"Invalid timeout argument: %s\n",optarg);
+		return usage(progname,1);
+	      }
+	  }
+	  break;
+	case 'T':
+	  {
+	    char garbage[3];
+	    if ((sscanf(optarg,"%ld%1s",&gs.restart_timeout,garbage) != 1) ||
+	        (gs.restart_timeout < 1))
+	      {
+	        fprintf(stderr,"Invalid restart timeout argument: %s\n",optarg);
+		return usage(progname,1);
+	      }
+	  }
+	  break;
+        case 'z':
+	  gs.unresponsive_restart = 1;
+	  break;
+	case 'v':
+	  printf ("%s version %s\n", progname, QUAGGA_VERSION);
+	  puts("Copyright 2004 Andrew J. Schorr");
+	  return 0;
+        case 'h':
+	  return usage(progname,0);
+        default:
+	  fputs("Invalid option.\n",stderr);
+	  return usage(progname,1);
+        }
+    }
+  
+  if (gs.unresponsive_restart && (gs.mode == MODE_MONITOR))
+    {
+      fputs("Option -z requires a -r or -R restart option.\n",stderr);
+      return usage(progname,1);
+    }
+  switch (gs.mode)
+    {
+    case MODE_MONITOR:
+      if (gs.restart_command || gs.start_command || gs.stop_command)
+        {
+	  fprintf(stderr,"No kill/(re)start commands needed for %s mode.\n",
+		  mode_str[gs.mode]);
+	  return usage(progname,1);
+	}
+      break;
+    case MODE_GLOBAL_RESTART:
+    case MODE_SEPARATE_RESTART:
+      if (!gs.restart_command || gs.start_command || gs.stop_command)
+        {
+	  fprintf(stderr,"No start/kill commands needed in [%s] mode.\n",
+		  mode_str[gs.mode]);
+	  return usage(progname,1);
+	}
+      break;
+    case MODE_PHASED_ZEBRA_RESTART:
+    case MODE_PHASED_ALL_RESTART:
+      if (!gs.restart_command || !gs.start_command || !gs.stop_command)
+        {
+	  fprintf(stderr,
+	  	  "Need start, kill, and restart commands in [%s] mode.\n",
+		  mode_str[gs.mode]);
+	  return usage(progname,1);
+	}
+      break;
+    }
+
+  gs.restart.interval = gs.min_restart_interval;
+  master = thread_master_create();
+  signal_init (master, Q_SIGC(my_signals), my_signals);
+  srandom(time(NULL));
+
+  {
+    int i;
+    struct daemon *tail = NULL;
+
+    for (i = optind; i < argc; i++)
+      {
+	struct daemon *dmn;
+
+	if (!(dmn = (struct daemon *)calloc(1,sizeof(*dmn))))
+	  {
+	    fprintf(stderr,"calloc(1,%zu) failed: %s\n",
+		    sizeof(*dmn), safe_strerror(errno));
+	    return 1;
+	  }
+	dmn->name = dmn->restart.name = argv[i];
+	dmn->state = DAEMON_INIT;
+	gs.numdaemons++;
+	gs.numdown++;
+	dmn->fd = -1;
+	dmn->t_wakeup = thread_add_timer_msec(master,wakeup_init,dmn,
+					      100+(random() % 900));
+	dmn->restart.interval = gs.min_restart_interval;
+	if (tail)
+	  tail->next = dmn;
+	else
+	  gs.daemons = dmn;
+	tail = dmn;
+
+	if (((gs.mode == MODE_PHASED_ZEBRA_RESTART) ||
+	     (gs.mode == MODE_PHASED_ALL_RESTART)) &&
+	    !strcmp(dmn->name,special))
+	  gs.special = dmn;
+      }
+  }
+  if (!gs.daemons)
+    {
+      fputs("Must specify one or more daemons to monitor.\n",stderr);
+      return usage(progname,1);
+    }
+  if (((gs.mode == MODE_PHASED_ZEBRA_RESTART) ||
+      (gs.mode == MODE_PHASED_ALL_RESTART)) && !gs.special)
+    {
+      fprintf(stderr,"In mode [%s], but cannot find master daemon %s\n",
+	      mode_str[gs.mode],special);
+      return usage(progname,1);
+    }
+  if (gs.special && (gs.numdaemons < 2))
+    {
+      fprintf(stderr,"Mode [%s] does not make sense with only 1 daemon "
+		     "to watch.\n",mode_str[gs.mode]);
+      return usage(progname,1);
+    }
+
+  zlog_default = openzlog(progname, ZLOG_NONE,
+			  LOG_CONS|LOG_NDELAY|LOG_PID, LOG_DAEMON);
+  zlog_set_level(NULL, ZLOG_DEST_MONITOR, ZLOG_DISABLED);
+  if (daemon_mode)
+    {
+      zlog_set_level(NULL, ZLOG_DEST_SYSLOG, MIN(gs.loglevel,LOG_DEBUG));
+      daemon(0, 0);
+    }
+  else
+    zlog_set_level(NULL, ZLOG_DEST_STDOUT, MIN(gs.loglevel,LOG_DEBUG));
+
+  /* Make sure we're not already running. */
+  pid_output (pidfile);
+
+  /* Announce which daemons are being monitored. */
+  {
+    struct daemon *dmn;
+    size_t len = 0;
+
+    for (dmn = gs.daemons; dmn; dmn = dmn->next)
+      len += strlen(dmn->name)+1;
+
+    {
+      char buf[len+1];
+      char *p = buf;
+
+      for (dmn = gs.daemons; dmn; dmn = dmn->next)
+	{
+	  if (p != buf)
+	    *p++ = ' ';
+	  strcpy(p,dmn->name);
+	  p += strlen(p);
+	}
+      zlog_notice("%s %s watching [%s], mode [%s]",
+      		  progname, QUAGGA_VERSION, buf, mode_str[gs.mode]);
+    }
+  }
+
+  {
+    struct thread thread;
+
+    while (thread_fetch (master, &thread))
+      thread_call (&thread);
+  }
+
+  /* Not reached. */
+  return 0;
+}