syncdaemon: have the monitor kill the worker if it does not connect in 60 sec

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Anand Avati <avati@gluster.com>

BUG: 2736 (gsyncd hangs if crash occurs in the non-main thread)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2736

3 files changed, 33 insertions, 4 deletions

diff --git a/xlators/features/marker/utils/syncdaemon/gsyncd.py b/xlators/features/marker/utils/syncdaemon/gsyncd.py
index c52d1a218..60980f546 100644
--- a/xlators/features/marker/utils/syncdaemon/gsyncd.py
+++ b/xlators/features/marker/utils/syncdaemon/gsyncd.py
@@ -140,6 +140,7 @@ def main_i():
     op.add_option('-c', '--config-file',   metavar='CONF',  type=str, action='callback', callback=store_local)
     # duh. need to specify dest or value will be mapped to None :S
     op.add_option('--monitor', dest='monitor', action='callback', callback=store_local_curry(True))
+    op.add_option('--feedback-fd', dest='feedback_fd', type=int, help=SUPPRESS_HELP, action='callback', callback=store_local)
     op.add_option('--listen', dest='listen', help=SUPPRESS_HELP,      action='callback', callback=store_local_curry(True))
     op.add_option('-N', '--no-daemon', dest="go_daemon",    action='callback', callback=store_local_curry('dont'))
     op.add_option('--debug', dest="go_daemon",              action='callback', callback=lambda *a: (store_local_curry('dont')(*a),
@@ -246,6 +247,11 @@ def main_i():
     gconf.__dict__.update(opts.__dict__)
     gconf.configinterface = gcnf
 
+    ffd = rconf.get('feedback_fd')
+    if ffd:
+        gconf.feedback_fd = ffd
+        fcntl.fcntl(int(ffd), fcntl.F_SETFD, fcntl.FD_CLOEXEC)
+
     #normalize loglevel
     lvl0 = gconf.log_level
     if isinstance(lvl0, str):
diff --git a/xlators/features/marker/utils/syncdaemon/master.py b/xlators/features/marker/utils/syncdaemon/master.py
index 35dc4ee06..76f924ed3 100644
--- a/xlators/features/marker/utils/syncdaemon/master.py
+++ b/xlators/features/marker/utils/syncdaemon/master.py
@@ -87,6 +87,9 @@ class GMaster(object):
 	self.terminate = False
 
     def crawl_loop(self):
+        ffd = getattr(gconf, 'feedback_fd', None)
+        if ffd:
+            os.close(int(ffd))
         timo = int(gconf.timeout or 0)
         if timo > 0:
             def keep_alive():
diff --git a/xlators/features/marker/utils/syncdaemon/monitor.py b/xlators/features/marker/utils/syncdaemon/monitor.py
index 5e5d22f4f..a86acdc75 100644
--- a/xlators/features/marker/utils/syncdaemon/monitor.py
+++ b/xlators/features/marker/utils/syncdaemon/monitor.py
@@ -2,6 +2,8 @@ import os
 import sys
 import time
 import logging
+import select
+from signal import SIGKILL
 from gconf import gconf
 from syncdutils import update_file
 
@@ -35,12 +37,30 @@ class Monitor(object):
             if os.WIFEXITED(r):
                 return os.WEXITSTATUS(r)
             return 1
+        conn_timeout = 60
         while ret in (0, 1):
-            logging.info('-' * 60)
+            logging.info('-' * conn_timeout)
             logging.info('starting gsyncd worker')
-            cpid = os.spawnv(os.P_NOWAIT, sys.executable, argv)
-            time.sleep(60)
-            ret = nwait(cpid, os.WNOHANG)
+            pr, pw = os.pipe()
+            cpid = os.fork()
+            if cpid == 0:
+                os.close(pr)
+                os.execv(sys.executable, argv + ['--feedback-fd', str(pw)])
+            os.close(pw)
+            t0 = time.time()
+            select.select((pr,), (), (), conn_timeout)
+            os.close(pr)
+            et = time.time() - t0
+            if et < conn_timeout:
+                et2 = conn_timeout - et
+                logging.debug("worker got connected in %d sec, "
+                              "waiting %d more to make sure it's fine" % (et, et2))
+                time.sleep(et2)
+                ret = nwait(cpid, os.WNOHANG)
+            else:
+                logging.debug("worker not confirmed in %d sec, aborting it" % et)
+                os.kill(cpid, SIGKILL)
+                ret = nwait(cpid)
             if ret == None:
                 self.set_state('OK')
                 ret = nwait(cpid)