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authorCsaba Henk <csaba@gluster.com>2011-02-15 10:52:32 +0000
committerAnand V. Avati <avati@dev.gluster.com>2011-02-15 21:44:43 -0800
commit1569424d1425a2f81c428d3968cd103ab2cad49e (patch)
tree51f2233a8434eaae6068ea93d2be4b5b5497af03 /xlators
parenta68b4ad416970ec0ca710f650f54b87c3b92428e (diff)
syncdaemon: change pidfile handling approach
Signal handling of the python interpreter is a bit messy, so we cannot rely on executing a final clause upon termination. Switch over fcntl lock based pidfile handling which can provide reliable info about status of the process. (Due to aforementioned reason, pidfile as such is not guaranteed to be cleaned up, but lock acquisition is a reliable measure.) Signed-off-by: Csaba Henk <csaba@gluster.com> Signed-off-by: Anand V. Avati <avati@dev.gluster.com> BUG: 1570 (geosync related changes) URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1570
Diffstat (limited to 'xlators')
-rw-r--r--xlators/features/marker/utils/syncdaemon/gconf.py1
-rw-r--r--xlators/features/marker/utils/syncdaemon/gsyncd.py73
-rw-r--r--xlators/features/marker/utils/syncdaemon/resource.py2
3 files changed, 48 insertions, 28 deletions
diff --git a/xlators/features/marker/utils/syncdaemon/gconf.py b/xlators/features/marker/utils/syncdaemon/gconf.py
index 7bedce514..cec5be078 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
+ permanent_handles = []
@classmethod
def setup_ssh_ctl(cls, ctld):
diff --git a/xlators/features/marker/utils/syncdaemon/gsyncd.py b/xlators/features/marker/utils/syncdaemon/gsyncd.py
index 8a91c5ef9..b8b92056b 100644
--- a/xlators/features/marker/utils/syncdaemon/gsyncd.py
+++ b/xlators/features/marker/utils/syncdaemon/gsyncd.py
@@ -9,9 +9,10 @@ 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
+from errno import EEXIST, ENOENT, EACCES, EAGAIN
from gconf import gconf
from configinterface import GConffile
@@ -53,26 +54,42 @@ class GLogger(Logger):
logging.basicConfig(**lprm)
-def startup(**kw):
- def write_pid(fn):
- fd = None
+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:
- fd = os.open(fn, os.O_CREAT|os.O_TRUNC|os.O_WRONLY|os.O_EXCL)
- os.write(fd, str(os.getpid()) + '\n')
- finally:
- if fd:
- os.close(fd)
+ 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 startup(**kw):
if getattr(gconf, 'pid_file', None) and kw.get('go_daemon') != 'postconn':
- try:
- write_pid(gconf.pid_file)
- except OSError:
- gconf.pid_file = None
- ex = sys.exc_info()[1]
- if ex.errno == EEXIST:
- sys.stderr.write("pidfile is taken, exiting.\n")
- exit(2)
- raise
+ if not grabpidfile():
+ sys.stderr.write("pidfile is taken, exiting.\n")
+ exit(2)
if kw.get('go_daemon') == 'should':
x, y = os.pipe()
@@ -86,7 +103,8 @@ def startup(**kw):
for f in (sys.stdin, sys.stdout, sys.stderr):
os.dup2(dn, f.fileno())
if getattr(gconf, 'pid_file', None):
- write_pid(gconf.pid_file + '.tmp')
+ if not grabpidfile(gconf.pid_file + '.tmp'):
+ raise RuntimeError("cannot grap temporary pidfile")
os.rename(gconf.pid_file + '.tmp', gconf.pid_file)
# wait for parent to terminate
# so we can start up with
@@ -102,20 +120,21 @@ def startup(**kw):
def finalize(*a):
if getattr(gconf, 'pid_file', None):
+ rm_pidf = True
if gconf.cpid:
+ # exit path from parent branch of daemonization
+ rm_pidf = False
while True:
- f = open(gconf.pid_file)
- pid = f.read()
- f.close()
- pid = int(pid.strip())
- if pid == gconf.cpid:
+ f = grabpidfile(setpid=False)
+ if not f:
+ # child has already taken over pidfile
break
- if pid != os.getpid():
- raise RuntimeError("corrupt pidfile")
if os.waitpid(gconf.cpid, os.WNOHANG)[0] == gconf.cpid:
+ # child has terminated
+ rm_pidf = True
break;
time.sleep(0.1)
- else:
+ if rm_pidf:
try:
os.unlink(gconf.pid_file)
except:
diff --git a/xlators/features/marker/utils/syncdaemon/resource.py b/xlators/features/marker/utils/syncdaemon/resource.py
index 1005e4086..6697ab8c4 100644
--- a/xlators/features/marker/utils/syncdaemon/resource.py
+++ b/xlators/features/marker/utils/syncdaemon/resource.py
@@ -433,7 +433,7 @@ class SSH(AbstractUrl, SlaveRemote):
repce.recv(inf)
# hack hack hack: store a global reference to the file
# to save it from getting GC'd which implies closing it
- gconf._in_fd_reference = inf
+ gconf.permanent_handles.append(inf)
self.fd_pair = (i, o)
return 'should'