-# Copyright (c) 2010, 2011 Nicira Networks
+# Copyright (c) 2010, 2011, 2012 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
import errno
import fcntl
-import logging
import os
import resource
import signal
import ovs.socket_util
import ovs.timeval
import ovs.util
+import ovs.vlog
+
+vlog = ovs.vlog.Vlog("daemon")
# --detach: Should we run in the background?
_detach = False
RESTART_EXIT_CODE = 5
+
def make_pidfile_name(name):
"""Returns the file name that would be used for a pidfile if 'name' were
provided to set_pidfile()."""
else:
return ovs.util.abs_file_name(ovs.dirs.RUNDIR, name)
+
def set_pidfile(name):
"""Sets up a following call to daemonize() to create a pidfile named
'name'. If 'name' begins with '/', then it is treated as an absolute path.
Otherwise, it is taken relative to ovs.util.RUNDIR, which is
$(prefix)/var/run by default.
-
+
If 'name' is null, then ovs.util.PROGRAM_NAME followed by ".pid" is
used."""
global _pidfile
_pidfile = make_pidfile_name(name)
+
def get_pidfile():
"""Returns an absolute path to the configured pidfile, or None if no
- pidfile is configured. The caller must not modify or free the returned
- string."""
+ pidfile is configured."""
return _pidfile
+
def set_no_chdir():
"""Sets that we do not chdir to "/"."""
global _chdir
_chdir = False
+
def is_chdir_enabled():
"""Will we chdir to "/" as part of daemonizing?"""
return _chdir
+
def ignore_existing_pidfile():
"""Normally, daemonize() or daemonize_start() will terminate the program
with a message if a locked pidfile already exists. If this function is
global _overwrite_pidfile
_overwrite_pidfile = True
+
def set_detach():
"""Sets up a following call to daemonize() to detach from the foreground
session, running this process in the background."""
global _detach
_detach = True
+
def get_detach():
"""Will daemonize() really detach?"""
return _detach
+
def set_monitor():
"""Sets up a following call to daemonize() to fork a supervisory process to
monitor the daemon and restart it if it dies due to an error signal."""
global _monitor
_monitor = True
+
def _fatal(msg):
- logging.error(msg)
+ vlog.err(msg)
sys.stderr.write("%s\n" % msg)
sys.exit(1)
+
def _make_pidfile():
"""If a pidfile has been configured, creates it and stores the running
process's pid in it. Ensures that the pidfile will be deleted when the
# This is global to keep Python from garbage-collecting and
# therefore closing our file after this function exits. That would
# unlock the lock for us, and we don't want that.
- global file
+ global file_handle
- file = open(tmpfile, "w")
+ file_handle = open(tmpfile, "w")
except IOError, e:
_fatal("%s: create failed (%s)" % (tmpfile, e.strerror))
try:
- s = os.fstat(file.fileno())
+ s = os.fstat(file_handle.fileno())
except IOError, e:
_fatal("%s: fstat failed (%s)" % (tmpfile, e.strerror))
try:
- file.write("%s\n" % pid)
- file.flush()
+ file_handle.write("%s\n" % pid)
+ file_handle.flush()
except OSError, e:
_fatal("%s: write failed: %s" % (tmpfile, e.strerror))
try:
- fcntl.lockf(file, fcntl.LOCK_EX | fcntl.LOCK_NB)
+ fcntl.lockf(file_handle, fcntl.LOCK_EX | fcntl.LOCK_NB)
except IOError, e:
_fatal("%s: fcntl failed: %s" % (tmpfile, e.strerror))
_fatal("failed to link \"%s\" as \"%s\" (%s)"
% (tmpfile, _pidfile, os.strerror(error)))
-
# Ensure that the pidfile will get deleted on exit.
ovs.fatal_signal.add_file_to_unlink(_pidfile)
if error:
_fatal("%s: unlink failed (%s)" % (tmpfile, os.strerror(error)))
+ global _pidfile_dev
+ global _pidfile_ino
_pidfile_dev = s.st_dev
_pidfile_ino = s.st_ino
+
def daemonize():
"""If configured with set_pidfile() or set_detach(), creates the pid file
and detaches from the foreground session."""
daemonize_start()
daemonize_complete()
+
def _waitpid(pid, options):
while True:
try:
pass
return -e.errno, 0
+
def _fork_and_wait_for_startup():
try:
rfd, wfd = os.pipe()
break
if len(s) != 1:
retval, status = _waitpid(pid, 0)
- if (retval == pid and
- os.WIFEXITED(status) and os.WEXITSTATUS(status)):
- # Child exited with an error. Convey the same error to
- # our parent process as a courtesy.
- sys.exit(os.WEXITSTATUS(status))
+ if retval == pid:
+ if os.WIFEXITED(status) and os.WEXITSTATUS(status):
+ # Child exited with an error. Convey the same error to
+ # our parent process as a courtesy.
+ sys.exit(os.WEXITSTATUS(status))
+ else:
+ sys.stderr.write("fork child failed to signal "
+ "startup (%s)\n"
+ % ovs.process.status_msg(status))
else:
- sys.stderr.write("fork child failed to signal startup\n")
+ assert retval < 0
+ sys.stderr.write("waitpid failed (%s)\n"
+ % os.strerror(-retval))
sys.exit(1)
os.close(rfd)
_daemonize_fd = wfd
return pid
+
def _fork_notify_startup(fd):
if fd is not None:
error, bytes_written = ovs.socket_util.write_fully(fd, "0")
sys.exit(1)
os.close(fd)
+
def _should_restart(status):
global RESTART_EXIT_CODE
if os.WIFSIGNALED(status):
for signame in ("SIGABRT", "SIGALRM", "SIGBUS", "SIGFPE", "SIGILL",
"SIGPIPE", "SIGSEGV", "SIGXCPU", "SIGXFSZ"):
- if (signame in signal.__dict__ and
- os.WTERMSIG(status) == signal.__dict__[signame]):
+ if os.WTERMSIG(status) == getattr(signal, signame, None):
return True
return False
+
def _monitor_daemon(daemon_pid):
# XXX should log daemon's stderr output at startup time
# XXX should use setproctitle module if available
elif retval == daemon_pid:
status_msg = ("pid %d died, %s"
% (daemon_pid, ovs.process.status_msg(status)))
-
+
if _should_restart(status):
if os.WCOREDUMP(status):
# Disable further core dumps to save disk space.
try:
resource.setrlimit(resource.RLIMIT_CORE, (0, 0))
except resource.error:
- logging.warning("failed to disable core dumps")
+ vlog.warn("failed to disable core dumps")
# Throttle restarts to no more than once every 10 seconds.
if (last_restart is not None and
ovs.timeval.msec() < last_restart + 10000):
- logging.warning("%s, waiting until 10 seconds since last "
- "restart" % status_msg)
+ vlog.warn("%s, waiting until 10 seconds since last "
+ "restart" % status_msg)
while True:
now = ovs.timeval.msec()
wakeup = last_restart + 10000
time.sleep((wakeup - now) / 1000.0)
last_restart = ovs.timeval.msec()
- logging.error("%s, restarting" % status_msg)
+ vlog.err("%s, restarting" % status_msg)
daemon_pid = _fork_and_wait_for_startup()
if not daemon_pid:
break
else:
- logging.info("%s, exiting" % status_msg)
+ vlog.info("%s, exiting" % status_msg)
sys.exit(0)
# Running in new daemon process.
+
def _close_standard_fds():
"""Close stdin, stdout, stderr. If we're started from e.g. an SSH session,
then this keeps us from holding that session open artificially."""
os.dup2(null_fd, 1)
os.dup2(null_fd, 2)
+
def daemonize_start():
"""If daemonization is configured, then starts daemonization, by forking
and returning in the child process. The parent process hangs around until
the child lets it know either that it completed startup successfully (by
calling daemon_complete()) or that it failed to start up (by exiting with a
nonzero exit code)."""
-
+
if _detach:
if _fork_and_wait_for_startup() > 0:
# Running in parent process.
sys.exit(0)
+
# Running in daemon or monitor process.
+ os.setsid()
if _monitor:
saved_daemonize_fd = _daemonize_fd
_close_standard_fds()
_monitor_daemon(daemon_pid)
# Running in daemon process
-
+
if _pidfile:
_make_pidfile()
+
def daemonize_complete():
"""If daemonization is configured, then this function notifies the parent
process that the child process has completed startup successfully."""
_fork_notify_startup(_daemonize_fd)
if _detach:
- os.setsid()
if _chdir:
os.chdir("/")
_close_standard_fds()
+
def usage():
sys.stdout.write("""
Daemon options:
--overwrite-pidfile with --pidfile, start even if already running
""" % (ovs.dirs.RUNDIR, ovs.util.PROGRAM_NAME))
+
def __read_pidfile(pidfile, delete_if_stale):
if _pidfile_dev is not None:
try:
pass
try:
- file = open(pidfile, "r+")
+ file_handle = open(pidfile, "r+")
except IOError, e:
if e.errno == errno.ENOENT and delete_if_stale:
return 0
- logging.warning("%s: open: %s" % (pidfile, e.strerror))
+ vlog.warn("%s: open: %s" % (pidfile, e.strerror))
return -e.errno
# Python fcntl doesn't directly support F_GETLK so we have to just try
# to lock it.
try:
- fcntl.lockf(file, fcntl.LOCK_EX | fcntl.LOCK_NB)
+ fcntl.lockf(file_handle, fcntl.LOCK_EX | fcntl.LOCK_NB)
# pidfile exists but wasn't locked by anyone. Now we have the lock.
if not delete_if_stale:
- file.close()
- logging.warning("%s: pid file is stale" % pidfile)
+ file_handle.close()
+ vlog.warn("%s: pid file is stale" % pidfile)
return -errno.ESRCH
# Is the file we have locked still named 'pidfile'?
try:
raced = False
s = os.stat(pidfile)
- s2 = os.fstat(file.fileno())
+ s2 = os.fstat(file_handle.fileno())
if s.st_ino != s2.st_ino or s.st_dev != s2.st_dev:
raced = True
except IOError:
raced = True
if raced:
- logging.warning("%s: lost race to delete pidfile" % pidfile)
- return -errno.ALREADY
+ vlog.warn("%s: lost race to delete pidfile" % pidfile)
+ return -errno.EALREADY
# We won the right to delete the stale pidfile.
try:
os.unlink(pidfile)
except IOError, e:
- logging.warning("%s: failed to delete stale pidfile"
+ vlog.warn("%s: failed to delete stale pidfile (%s)"
% (pidfile, e.strerror))
return -e.errno
-
- logging.debug("%s: deleted stale pidfile" % pidfile)
- file.close()
- return 0
+ else:
+ vlog.dbg("%s: deleted stale pidfile" % pidfile)
+ file_handle.close()
+ return 0
except IOError, e:
if e.errno not in [errno.EACCES, errno.EAGAIN]:
- logging.warn("%s: fcntl: %s" % (pidfile, e.strerror))
+ vlog.warn("%s: fcntl: %s" % (pidfile, e.strerror))
return -e.errno
# Someone else has the pidfile locked.
try:
try:
- return int(file.readline())
+ error = int(file_handle.readline())
except IOError, e:
- logging.warning("%s: read: %s" % (pidfile, e.strerror))
- return -e.errno
+ vlog.warn("%s: read: %s" % (pidfile, e.strerror))
+ error = -e.errno
except ValueError:
- logging.warning("%s does not contain a pid" % pidfile)
- return -errno.EINVAL
+ vlog.warn("%s does not contain a pid" % pidfile)
+ error = -errno.EINVAL
+
+ return error
finally:
try:
- file.close()
+ file_handle.close()
except IOError:
pass
+
def read_pidfile(pidfile):
"""Opens and reads a PID from 'pidfile'. Returns the positive PID if
successful, otherwise a negative errno value."""
return __read_pidfile(pidfile, False)
+
def _check_already_running():
pid = __read_pidfile(_pidfile, True)
if pid > 0:
_fatal("%s: pidfile check failed (%s), aborting"
% (_pidfile, os.strerror(pid)))
-# XXX Python's getopt does not support options with optional arguments, so we
-# have to separate --pidfile (with no argument) from --pidfile-name (with an
-# argument). Need to write our own getopt I guess.
-LONG_OPTIONS = ["detach", "no-chdir", "pidfile", "pidfile-name=",
- "overwrite-pidfile", "monitor"]
-def parse_opt(option, arg):
- if option == '--detach':
+def add_args(parser):
+ """Populates 'parser', an ArgumentParser allocated using the argparse
+ module, with the command line arguments required by the daemon module."""
+
+ pidfile = make_pidfile_name(None)
+
+ group = parser.add_argument_group(title="Daemon Options")
+ group.add_argument("--detach", action="store_true",
+ help="Run in background as a daemon.")
+ group.add_argument("--no-chdir", action="store_true",
+ help="Do not chdir to '/'.")
+ group.add_argument("--monitor", action="store_true",
+ help="Monitor %s process." % ovs.util.PROGRAM_NAME)
+ group.add_argument("--pidfile", nargs="?", const=pidfile,
+ help="Create pidfile (default %s)." % pidfile)
+ group.add_argument("--overwrite-pidfile", action="store_true",
+ help="With --pidfile, start even if already running.")
+
+
+def handle_args(args):
+ """Handles daemon module settings in 'args'. 'args' is an object
+ containing values parsed by the parse_args() method of ArgumentParser. The
+ parent ArgumentParser should have been prepared by add_args() before
+ calling parse_args()."""
+
+ if args.detach:
set_detach()
- elif option == '--no-chdir':
+
+ if args.no_chdir:
set_no_chdir()
- elif option == '--pidfile':
- set_pidfile(None)
- elif option == '--pidfile-name':
- set_pidfile(arg)
- elif option == '--overwrite-pidfile':
+
+ if args.pidfile:
+ set_pidfile(args.pidfile)
+
+ if args.overwrite_pidfile:
ignore_existing_pidfile()
- elif option == '--monitor':
+
+ if args.monitor:
set_monitor()
- else:
- return False
- return True
projects / cascardo / ovs.git / blobdiff