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daemon.py: Whitespace cleanup.

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The python style guide requires two newlines between top level
definitions.  This patch also removes some trailing whitespace.
This commit is contained in:
Ethan Jackson
2011-09-16 16:03:31 -07:00
parent 50e97486ca
commit cadc9871c2
1 changed files with 29 additions and 5 deletions
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34
python/ovs/daemon.py
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@@ -54,6 +54,7 @@ _daemonize_fd = None
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()."""
@@ -62,31 +63,36 @@ def make_pidfile_name(name):
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."""
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
@@ -94,27 +100,32 @@ def ignore_existing_pidfile():
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)
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
@@ -172,7 +183,6 @@ def _make_pidfile():
_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)
@@ -187,12 +197,14 @@ def _make_pidfile():
_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:
@@ -202,6 +214,7 @@ def _waitpid(pid, options):
pass
return -e.errno, 0
def _fork_and_wait_for_startup():
try:
rfd, wfd = os.pipe()
@@ -250,6 +263,7 @@ def _fork_and_wait_for_startup():
_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")
@@ -258,6 +272,7 @@ def _fork_notify_startup(fd):
sys.exit(1)
os.close(fd)
def _should_restart(status):
global RESTART_EXIT_CODE
@@ -271,6 +286,7 @@ def _should_restart(status):
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
@@ -283,7 +299,7 @@ def _monitor_daemon(daemon_pid):
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.
@@ -316,6 +332,7 @@ def _monitor_daemon(daemon_pid):
# 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."""
@@ -325,13 +342,14 @@ def _close_standard_fds():
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.
@@ -347,10 +365,11 @@ def daemonize_start():
_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."""
@@ -362,6 +381,7 @@ def daemonize_complete():
os.chdir("/")
_close_standard_fds()
def usage():
sys.stdout.write("""
Daemon options:
@@ -371,6 +391,7 @@ 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:
@@ -449,11 +470,13 @@ def __read_pidfile(pidfile, delete_if_stale):
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:
@@ -468,6 +491,7 @@ def _check_already_running():
LONG_OPTIONS = ["detach", "no-chdir", "pidfile", "pidfile-name=",
"overwrite-pidfile", "monitor"]
def parse_opt(option, arg):
if option == '--detach':
set_detach()