+"""A few things that didn't seem to fit anywhere else."""
+
import cPickle
import errno
import os
import pwd
import tempfile
import threading
+import fcntl
-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
+ for fd in range(3, os.sysconf(_SC_OPEN_MAX)):
+ 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():
os.chdir('/')
os.umask(0)
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))
-
+ os.dup2(devnull, 0)
+ crashlog = os.open('/root/nm.stderr', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
+ os.dup2(crashlog, 1)
+ os.dup2(crashlog, 2)
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."""
if child_pid == 0:
try:
os.chdir('/')
- # close all nonstandard file descriptors
- _SC_OPEN_MAX = 4
- for fd in range(3, os.sysconf(_SC_OPEN_MAX)):
- try: os.close(fd)
- except OSError: pass # most likely an fd that isn't open
- pw_ent = pwd.getpwnam(su)
- os.setegid(pw_ent[3])
- os.seteuid(pw_ent[2])
+ close_nonstandard_fds()
+ if su:
+ pw_ent = pwd.getpwnam(su)
+ os.setegid(pw_ent[3])
+ os.seteuid(pw_ent[2])
child_pid = os.fork()
if child_pid == 0: function(*args)
except:
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
+
+
+class NMLock:
+ def __init__(self, file):
+ self.fd = os.open(file, os.O_RDWR|os.O_CREAT, 0600)
+ flags = fcntl.fcntl(self.fd, fcntl.F_GETFD)
+ flags |= fcntl.FD_CLOEXEC
+ fcntl.fcntl(self.fd, fcntl.F_SETFD, flags)
+ def __del__(self):
+ os.close(self.fd)
+ def acquire(self):
+ fcntl.lockf(self.fd, fcntl.LOCK_EX)
+ def release(self):
+ fcntl.lockf(self.fd, fcntl.LOCK_UN)
git://git.onelab.eu / nodemanager.git / blobdiff