syncdaemon: yet another try to exit properly

The final cleanup sequence + call to _exit, which was just done in the main
thread, now is called for in each thread when the thread crashes. Seems we
aren't left there hanging this way.

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, 92 insertions, 83 deletions

diff --git a/xlators/features/marker/utils/syncdaemon/gconf.py b/xlators/features/marker/utils/syncdaemon/gconf.py
index cec5be0789b..24165b6191a 100644
--- a/xlators/features/marker/utils/syncdaemon/gconf.py
+++ b/xlators/features/marker/utils/syncdaemon/gconf.py
@@ -4,6 +4,7 @@ class GConf(object):
     ssh_ctl_dir = None
     ssh_ctl_args = None
     cpid = None
+    pid_file_owned = False
     permanent_handles = []
 
     @classmethod
diff --git a/xlators/features/marker/utils/syncdaemon/gsyncd.py b/xlators/features/marker/utils/syncdaemon/gsyncd.py
index 0ed120e0397..ba4d7a6dda4 100644
--- a/xlators/features/marker/utils/syncdaemon/gsyncd.py
+++ b/xlators/features/marker/utils/syncdaemon/gsyncd.py
@@ -7,15 +7,14 @@ import time
 import logging
 import signal
 import select
-import shutil
 import optparse
 import fcntl
 from optparse import OptionParser, SUPPRESS_HELP
 from logging import Logger
-from errno import EEXIST, ENOENT, EACCES, EAGAIN
+from errno import EEXIST, ENOENT
 
 from gconf import gconf
-from syncdutils import FreeObject, norm
+from syncdutils import FreeObject, norm, grabpidfile, finalize, log_raise_exception
 from configinterface import GConffile
 import resource
 from monitor import monitor
@@ -53,47 +52,12 @@ class GLogger(Logger):
         logging.basicConfig(**lprm)
 
 
-def grabfile(fname, content=None):
-    # damn those messy open() mode codes
-    fd = os.open(fname, os.O_CREAT|os.O_RDWR)
-    f = os.fdopen(fd, 'r+b', 0)
-    try:
-        fcntl.lockf(f, fcntl.LOCK_EX|fcntl.LOCK_NB)
-    except:
-        ex = sys.exc_info()[1]
-        f.close()
-        if isinstance(ex, IOError) and ex.errno in (EACCES, EAGAIN):
-            # cannot grab, it's taken
-            return
-        raise
-    if content:
-        try:
-            f.truncate()
-            f.write(content)
-        except:
-            f.close()
-            raise
-    gconf.permanent_handles.append(f)
-    return f
-
-pid_file_owned = False
-
-def grabpidfile(fname=None, setpid=True):
-    if not fname:
-        fname = gconf.pid_file
-    content = None
-    if setpid:
-        content = str(os.getpid()) + '\n'
-    return grabfile(fname, content=content)
-
 def startup(**kw):
-    global pid_file_owned
-
     if getattr(gconf, 'pid_file', None) and kw.get('go_daemon') != 'postconn':
         if not grabpidfile():
             sys.stderr.write("pidfile is taken, exiting.\n")
             sys.exit(2)
-        pid_file_owned = True
+        gconf.pid_file_owned = True
 
     if kw.get('go_daemon') == 'should':
         x, y = os.pipe()
@@ -129,57 +93,19 @@ def startup(**kw):
             lkw['filename'] = kw['log_file']
     GLogger.setup(label=kw.get('label'), **lkw)
 
-def finalize(*a):
-    if getattr(gconf, 'pid_file', None):
-        rm_pidf = pid_file_owned
-        if gconf.cpid:
-            # exit path from parent branch of daemonization
-            rm_pidf = False
-            while True:
-                f = grabpidfile(setpid=False)
-                if not f:
-                    # child has already taken over pidfile
-                    break
-                if os.waitpid(gconf.cpid, os.WNOHANG)[0] == gconf.cpid:
-                    # child has terminated
-                    rm_pidf = True
-                    break;
-                time.sleep(0.1)
-        if rm_pidf:
-            try:
-                os.unlink(gconf.pid_file)
-            except:
-                ex = sys.exc_info()[1]
-                if ex.errno == ENOENT:
-                    pass
-                else:
-                    raise
-    if gconf.ssh_ctl_dir and not gconf.cpid:
-        shutil.rmtree(gconf.ssh_ctl_dir)
-    sys.stdout.flush()
-    sys.stderr.flush()
-
 def main():
     signal.signal(signal.SIGTERM, lambda *a: (finalize(*a), os._exit(1)))
     GLogger.setup()
-    exval = 0
+    excont = FreeObject(exval = 0)
     try:
         try:
             main_i()
         except:
-            exc = sys.exc_info()[1]
-            if isinstance(exc, SystemExit):
-                exval = exc.code or 0
-                raise
-            else:
-                logging.exception("FAIL: ")
-                sys.stderr.write("failed with %s.\n" % type(exc).__name__)
-                exval = 1
-                sys.exit(exval)
+            log_raise_exception(excont)
     finally:
         finalize()
         # force exit in non-main thread too
-        os._exit(exval)
+        os._exit(excont.exval)
 
 def main_i():
     rconf = {'go_daemon': 'should'}
diff --git a/xlators/features/marker/utils/syncdaemon/syncdutils.py b/xlators/features/marker/utils/syncdaemon/syncdutils.py
index 48694d238fd..c8f751d33f4 100644
--- a/xlators/features/marker/utils/syncdaemon/syncdutils.py
+++ b/xlators/features/marker/utils/syncdaemon/syncdutils.py
@@ -1,7 +1,15 @@
 import os
+import sys
+import time
 import fcntl
+import shutil
+import logging
 from threading import Thread as baseThread
-from signal import SIGTERM
+from errno import EACCES, EAGAIN
+from signal import SIGTERM, SIGKILL
+from time import sleep
+
+from gconf import gconf
 
 try:
     # py 3
@@ -49,6 +57,78 @@ def update_file(path, updater, merger = lambda f: True):
             if fx:
                 fx.close()
 
+def grabfile(fname, content=None):
+    # damn those messy open() mode codes
+    fd = os.open(fname, os.O_CREAT|os.O_RDWR)
+    f = os.fdopen(fd, 'r+b', 0)
+    try:
+        fcntl.lockf(f, fcntl.LOCK_EX|fcntl.LOCK_NB)
+    except:
+        ex = sys.exc_info()[1]
+        f.close()
+        if isinstance(ex, IOError) and ex.errno in (EACCES, EAGAIN):
+            # cannot grab, it's taken
+            return
+        raise
+    if content:
+        try:
+            f.truncate()
+            f.write(content)
+        except:
+            f.close()
+            raise
+    gconf.permanent_handles.append(f)
+    return f
+
+def grabpidfile(fname=None, setpid=True):
+    if not fname:
+        fname = gconf.pid_file
+    content = None
+    if setpid:
+        content = str(os.getpid()) + '\n'
+    return grabfile(fname, content=content)
+
+def finalize(*a):
+    if getattr(gconf, 'pid_file', None):
+        rm_pidf = gconf.pid_file_owned
+        if gconf.cpid:
+            # exit path from parent branch of daemonization
+            rm_pidf = False
+            while True:
+                f = grabpidfile(setpid=False)
+                if not f:
+                    # child has already taken over pidfile
+                    break
+                if os.waitpid(gconf.cpid, os.WNOHANG)[0] == gconf.cpid:
+                    # child has terminated
+                    rm_pidf = True
+                    break;
+                time.sleep(0.1)
+        if rm_pidf:
+            try:
+                os.unlink(gconf.pid_file)
+            except:
+                ex = sys.exc_info()[1]
+                if ex.errno == ENOENT:
+                    pass
+                else:
+                    raise
+    if gconf.ssh_ctl_dir and not gconf.cpid:
+        shutil.rmtree(gconf.ssh_ctl_dir)
+    sys.stdout.flush()
+    sys.stderr.flush()
+
+def log_raise_exception(excont):
+    exc = sys.exc_info()[1]
+    if isinstance(exc, SystemExit):
+        excont.exval = exc.code or 0
+        raise
+    else:
+        logging.exception("FAIL: ")
+        sys.stderr.write("failed with %s.\n" % type(exc).__name__)
+        excont.exval = 1
+        sys.exit(excont.exval)
+
 
 class FreeObject(object):
     """wildcard class for which any attribute can be set"""
@@ -63,13 +143,15 @@ class Thread(baseThread):
         tf = kw.get('target')
         if tf:
             def twrap(*aa):
+                excont = FreeObject(exval = 0)
                 try:
                     tf(*aa)
                 except:
                     try:
-                        raise
+                        log_raise_exception(excont)
                     finally:
-                        os.kill(os.getpid(), SIGTERM)
+                        finalize()
+                        os._exit(excont.exval)
             kw['target'] = twrap
         baseThread.__init__(self, *a, **kw)
         self.setDaemon(True)