1 """A few things that didn't seem to fit anywhere else."""
16 PID_FILE = '/var/run/nm.pid'
19 interface = get_if_from_hwaddr(get_hwaddr_from_plnode())
20 if not interface: interface = "eth0"
23 def get_hwaddr_from_plnode():
24 for line in open("/usr/share/boot/plnode.txt", 'r').readlines():
25 if line.startswith("NET_DEVICE"):
26 return line.split("=")[1].strip().strip('"')
29 def get_if_from_hwaddr(hwaddr):
32 dev_hwaddr = sioc.gifhwaddr(dev)
33 if dev_hwaddr == hwaddr: return dev
36 def as_daemon_thread(run):
37 """Call function <run> with no arguments in its own thread."""
38 thr = threading.Thread(target=run)
42 def close_nonstandard_fds():
43 """Close all open file descriptors other than 0, 1, and 2."""
45 for fd in range(3, os.sysconf(_SC_OPEN_MAX)):
47 except OSError: pass # most likely an fd that isn't open
49 # after http://www.erlenstar.demon.co.uk/unix/faq_2.html
51 """Daemonize the current process."""
52 if os.fork() != 0: os._exit(0)
54 if os.fork() != 0: os._exit(0)
57 devnull = os.open(os.devnull, os.O_RDWR)
59 # xxx fixme - this is just to make sure that nothing gets stupidly lost - should use devnull
60 crashlog = os.open('/var/log/nm.daemon', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
64 def fork_as(su, function, *args):
65 """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."""
70 close_nonstandard_fds()
72 pw_ent = pwd.getpwnam(su)
76 if child_pid == 0: function(*args)
78 os.seteuid(os.getuid()) # undo su so we can write the log file
79 os.setegid(os.getgid())
82 else: os.waitpid(child_pid, 0)
85 """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."""
87 if os.access(PID_FILE, os.F_OK): # check for a pid file
88 handle = open(PID_FILE) # pid file exists, read it
89 other_pid = int(handle.read())
91 # check for a process with that pid by sending signal 0
92 try: os.kill(other_pid, 0)
94 if e.errno == errno.ESRCH: other_pid = None # doesn't exist
95 else: raise # who knows
97 # write a new pid file
98 write_file(PID_FILE, lambda f: f.write(str(os.getpid())))
101 def write_file(filename, do_write, **kw_args):
102 """Write file <filename> atomically by opening a temporary file, using <do_write> to write that file, and then renaming the temporary file."""
103 os.rename(write_temp_file(do_write, **kw_args), filename)
105 def write_temp_file(do_write, mode=None, uidgid=None):
106 fd, temporary_filename = tempfile.mkstemp()
107 if mode: os.chmod(temporary_filename, mode)
108 if uidgid: os.chown(temporary_filename, *uidgid)
109 f = os.fdopen(fd, 'w')
112 return temporary_filename
114 # utilities functions to get (cached) information from the node
116 # get node_id from /etc/planetlab/node_id and cache it
122 _node_id=int(file("/etc/planetlab/node_id").read())
127 # get slicefamily from /etc/planetlab/slicefamily and cache it
128 # http://svn.planet-lab.org/wiki/SliceFamily
132 if _slicefamily is None:
134 _slicefamily=file("/etc/planetlab/slicefamily").read().strip()
139 _root_context_arch=None
140 def root_context_arch():
141 global _root_context_arch
142 if not _root_context_arch:
143 _root_context_arch=commands.getoutput("uname -i")
144 return _root_context_arch
148 def __init__(self, file):
149 logger.log("Lock %s initialized." % file, 2)
150 self.fd = os.open(file, os.O_RDWR|os.O_CREAT, 0600)
151 flags = fcntl.fcntl(self.fd, fcntl.F_GETFD)
152 flags |= fcntl.FD_CLOEXEC
153 fcntl.fcntl(self.fd, fcntl.F_SETFD, flags)
157 logger.log("Lock acquired.", 2)
158 fcntl.lockf(self.fd, fcntl.LOCK_SH)
160 logger.log("Lock released.", 2)
161 fcntl.lockf(self.fd, fcntl.LOCK_UN)