+"""A few things that didn't seem to fit anywhere else."""
+
import cPickle
import errno
import os
import tempfile
import threading
-from config import PID_FILE
import logger
+PID_FILE = '/var/run/nm.pid'
+
def as_daemon_thread(run):
"""Call function <run> with no arguments in its own thread."""
thr = threading.Thread(target=run)
thr.setDaemon(True)
thr.start()
-
def close_nonstandard_fds():
"""Close all open file descriptors other than 0, 1, and 2."""
_SC_OPEN_MAX = 4
try: os.close(fd)
except OSError: pass # most likely an fd that isn't open
-
# after http://www.erlenstar.demon.co.uk/unix/faq_2.html
def daemon():
"""Daemonize the current process."""
devnull = os.open(os.devnull, os.O_RDWR)
for fd in range(3): os.dup2(devnull, fd)
-
-def deepcopy(obj):
- """Return a deep copy of obj."""
- return cPickle.loads(cPickle.dumps(obj, -1))
-
-
def fork_as(su, function, *args):
"""fork(), cd / to avoid keeping unused directories open, close all nonstandard file descriptors (to avoid capturing open sockets), fork() again (to avoid zombies) and call <function> with arguments <args> in the grandchild process. If <su> is not None, set our group and user ids appropriately in the child process."""
child_pid = os.fork()
os._exit(0)
else: os.waitpid(child_pid, 0)
-
def pid_file():
"""We use a pid file to ensure that only one copy of NM is running at a given time. If successful, this function will write a pid file containing the pid of the current process. The return value is the pid of the other running process, or None otherwise."""
other_pid = None
- # check for a pid file
- if os.access(PID_FILE, os.F_OK):
- # pid file exists, read it
- handle = open(PID_FILE)
+ if os.access(PID_FILE, os.F_OK): # check for a pid file
+ handle = open(PID_FILE) # pid file exists, read it
other_pid = int(handle.read())
handle.close()
# check for a process with that pid by sending signal 0
else: raise # who knows
if other_pid == None:
# write a new pid file
- write_file(PID_FILE, lambda thefile: thefile.write(str(os.getpid())))
+ write_file(PID_FILE, lambda f: f.write(str(os.getpid())))
return other_pid
-
-def write_file(filename, do_write):
+def write_file(filename, do_write, **kw_args):
"""Write file <filename> atomically by opening a temporary file, using <do_write> to write that file, and then renaming the temporary file."""
- os.rename(write_temp_file(do_write), filename)
-
+ os.rename(write_temp_file(do_write, **kw_args), filename)
-def write_temp_file(do_write):
+def write_temp_file(do_write, mode=None, uidgid=None):
fd, temporary_filename = tempfile.mkstemp()
- thefile = os.fdopen(fd, 'w')
- do_write(thefile)
- thefile.close()
+ if mode: os.chmod(temporary_filename, mode)
+ if uidgid: os.chown(temporary_filename, *uidgid)
+ f = os.fdopen(fd, 'w')
+ try: do_write(f)
+ finally: f.close()
return temporary_filename