import pwd
import tempfile
import threading
+import fcntl
import logger
-PID_FILE = '/var/run/node_mgr.pid'
+PID_FILE = '/var/run/nm.pid'
def as_daemon_thread(run):
"""Call function <run> with no arguments in its own thread."""
os.chdir('/')
os.umask(0)
devnull = os.open(os.devnull, os.O_RDWR)
- for fd in range(3): os.dup2(devnull, fd)
+ os.dup2(devnull, 0)
+ # xxx fixme - this is just to make sure that nothing gets stupidly lost - should use devnull
+ crashlog = os.open('/var/log/nm.daemon', 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."""
try:
os.chdir('/')
close_nonstandard_fds()
- pw_ent = pwd.getpwnam(su)
- os.setegid(pw_ent[3])
- os.seteuid(pw_ent[2])
+ 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:
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()
+ 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):
+ logger.log("Lock %s initialized." % file, 2)
+ 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):
+ logger.log("Lock acquired.", 2)
+ fcntl.lockf(self.fd, fcntl.LOCK_SH)
+ def release(self):
+ logger.log("Lock released.", 2)
+ fcntl.lockf(self.fd, fcntl.LOCK_UN)