1 """A few things that didn't seem to fit anywhere else."""
13 PID_FILE = '/var/run/nm.pid'
16 interface = get_if_from_hwaddr(get_hwaddr_from_plnode())
17 if not interface: interface = "eth0"
20 def get_hwaddr_from_plnode():
22 for line in open("/usr/boot/plnode.txt", 'r').readlines():
23 if line.startswith("NET_DEVICE"):
24 return line.split("=")[1].strip().strip('"')
29 def get_if_from_hwaddr(hwaddr):
33 dev_hwaddr = sioc.gifhwaddr(dev)
34 if dev_hwaddr == hwaddr: return dev
37 def as_daemon_thread(run):
38 """Call function <run> with no arguments in its own thread."""
39 thr = threading.Thread(target=run)
43 def close_nonstandard_fds():
44 """Close all open file descriptors other than 0, 1, and 2."""
46 for fd in range(3, os.sysconf(_SC_OPEN_MAX)):
48 except OSError: pass # most likely an fd that isn't open
50 # after http://www.erlenstar.demon.co.uk/unix/faq_2.html
52 """Daemonize the current process."""
53 if os.fork() != 0: os._exit(0)
55 if os.fork() != 0: os._exit(0)
58 devnull = os.open(os.devnull, os.O_RDWR)
60 # xxx fixme - this is just to make sure that nothing gets stupidly lost - should use devnull
61 crashlog = os.open('/var/log/nm.daemon', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644)
65 def fork_as(su, function, *args):
66 """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."""
71 close_nonstandard_fds()
73 pw_ent = pwd.getpwnam(su)
77 if child_pid == 0: function(*args)
79 os.seteuid(os.getuid()) # undo su so we can write the log file
80 os.setegid(os.getgid())
83 else: os.waitpid(child_pid, 0)
86 """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."""
88 if os.access(PID_FILE, os.F_OK): # check for a pid file
89 handle = open(PID_FILE) # pid file exists, read it
90 other_pid = int(handle.read())
92 # check for a process with that pid by sending signal 0
93 try: os.kill(other_pid, 0)
95 if e.errno == errno.ESRCH: other_pid = None # doesn't exist
96 else: raise # who knows
98 # write a new pid file
99 write_file(PID_FILE, lambda f: f.write(str(os.getpid())))
102 def write_file(filename, do_write, **kw_args):
103 """Write file <filename> atomically by opening a temporary file, using <do_write> to write that file, and then renaming the temporary file."""
104 os.rename(write_temp_file(do_write, **kw_args), filename)
106 def write_temp_file(do_write, mode=None, uidgid=None):
107 fd, temporary_filename = tempfile.mkstemp()
108 if mode: os.chmod(temporary_filename, mode)
109 if uidgid: os.chown(temporary_filename, *uidgid)
110 f = os.fdopen(fd, 'w')
113 return temporary_filename
115 # replace a target file with a new contents - checks for changes
116 # can handle chmod if requested
117 # can also remove resulting file if contents are void, if requested
118 # performs atomically:
119 # writes in a tmp file, which is then renamed (from sliverauth originally)
120 # returns True if a change occurred, or the file is deleted
121 def replace_file_with_string (target, new_contents, chmod=None, remove_if_empty=False):
123 current=file(target).read()
126 if current==new_contents:
127 # if turns out to be an empty string, and remove_if_empty is set,
128 # then make sure to trash the file if it exists
129 if remove_if_empty and not new_contents and os.path.isfile(target):
130 logger.verbose("tools.replace_file_with_string: removing file %s"%target)
131 try: os.unlink(target)
134 # overwrite target file: create a temp in the same directory
135 path=os.path.dirname(target) or '.'
136 fd, name = tempfile.mkstemp('','repl',path)
137 os.write(fd,new_contents)
139 if os.path.exists(target):
141 os.rename(name,target)
142 if chmod: os.chmod(target,chmod)
145 # utilities functions to get (cached) information from the node
147 # get node_id from /etc/planetlab/node_id and cache it
153 _node_id=int(file("/etc/planetlab/node_id").read())
158 # get slicefamily from /etc/planetlab/slicefamily and cache it
159 # http://svn.planet-lab.org/wiki/SliceFamily
163 if _slicefamily is None:
165 _slicefamily=file("/etc/planetlab/slicefamily").read().strip()
170 _root_context_arch=None
171 def root_context_arch():
172 global _root_context_arch
173 if not _root_context_arch:
174 _root_context_arch=commands.getoutput("uname -i")
175 return _root_context_arch
179 def __init__(self, file):
180 logger.log("Lock %s initialized." % file, 2)
181 self.fd = os.open(file, os.O_RDWR|os.O_CREAT, 0600)
182 flags = fcntl.fcntl(self.fd, fcntl.F_GETFD)
183 flags |= fcntl.FD_CLOEXEC
184 fcntl.fcntl(self.fd, fcntl.F_SETFD, flags)
188 logger.log("Lock acquired.", 2)
189 fcntl.lockf(self.fd, fcntl.LOCK_SH)
191 logger.log("Lock released.", 2)
192 fcntl.lockf(self.fd, fcntl.LOCK_UN)