+"""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
+import commands
import logger
-PID_FILE = '/var/run/pl_node_mgr.pid'
-
+PID_FILE = '/var/run/nm.pid'
def as_daemon_thread(run):
"""Call function <run> with no arguments in its own thread."""
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."""
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)
+ # 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:
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
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
+
+# utilities functions to get (cached) information from the node
+
+# get node_id from /etc/planetlab/node_id and cache it
+_node_id=None
+def node_id():
+ global _node_id
+ if _node_id is None:
+ try:
+ _node_id=int(file("/etc/planetlab/node_id").read())
+ except:
+ _node_id=""
+ return _node_id
+
+# get slicefamily from /etc/planetlab/slicefamily and cache it
+# http://svn.planet-lab.org/wiki/SliceFamily
+_slicefamily=None
+def slicefamily():
+ global _slicefamily
+ if _slicefamily is None:
+ try:
+ _slicefamily=file("/etc/planetlab/slicefamily").read().strip()
+ except:
+ _slicefamily=""
+ return _slicefamily
+
+_root_context_arch=None
+def root_context_arch():
+ global _root_context_arch
+ if not _root_context_arch:
+ _root_context_arch=commands.getoutput("uname -i")
+ return _root_context_arch
+
+
+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)