X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=tools.py;h=36754fc9fc45547c766555d72fcce55107d1270e;hb=refs%2Fheads%2Fopenvswitch;hp=f3e67e1595a185c907799d93f1f851526b084282;hpb=4293a16c3c0badbc130c3af6b62c3681a5eeb9d6;p=nodemanager.git diff --git a/tools.py b/tools.py index f3e67e1..36754fc 100644 --- a/tools.py +++ b/tools.py @@ -1,39 +1,43 @@ """A few things that didn't seem to fit anywhere else.""" -import cPickle -import errno -import os +import os, os.path import pwd import tempfile -import threading import fcntl -import commands +import errno +import threading +import subprocess +import shutil + import logger -try: - import sioc -except: - pass -PID_FILE = '/var/run/nm.pid' +PID_FILE = '/var/run/nodemanager.pid' +#################### def get_default_if(): interface = get_if_from_hwaddr(get_hwaddr_from_plnode()) if not interface: interface = "eth0" return interface def get_hwaddr_from_plnode(): - for line in open("/usr/boot/plnode.txt", 'r').readlines(): - if line.startswith("NET_DEVICE"): - return line.split("=")[1].strip().strip('"') + try: + for line in open("/usr/boot/plnode.txt", 'r').readlines(): + if line.startswith("NET_DEVICE"): + return line.split("=")[1].strip().strip('"') + except: + pass return None def get_if_from_hwaddr(hwaddr): + import sioc devs = sioc.gifconf() for dev in devs: dev_hwaddr = sioc.gifhwaddr(dev) if dev_hwaddr == hwaddr: return dev return None +#################### +# daemonizing def as_daemon_thread(run): """Call function with no arguments in its own thread.""" thr = threading.Thread(target=run) @@ -54,11 +58,11 @@ def daemon(): os.setsid() if os.fork() != 0: os._exit(0) os.chdir('/') - os.umask(0) + os.umask(0022) devnull = os.open(os.devnull, os.O_RDWR) 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) + crashlog = os.open('/var/log/nodemanager.daemon', os.O_RDWR | os.O_APPEND | os.O_CREAT, 0644) os.dup2(crashlog, 1) os.dup2(crashlog, 2) @@ -78,12 +82,16 @@ def fork_as(su, function, *args): except: os.seteuid(os.getuid()) # undo su so we can write the log file os.setegid(os.getgid()) - logger.log_exc() + logger.log_exc("tools: fork_as") os._exit(0) else: os.waitpid(child_pid, 0) +#################### +# manage files 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.""" + """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 if os.access(PID_FILE, os.F_OK): # check for a pid file handle = open(PID_FILE) # pid file exists, read it @@ -101,7 +109,7 @@ def pid_file(): def write_file(filename, do_write, **kw_args): """Write file atomically by opening a temporary file, using to write that file, and then renaming the temporary file.""" - os.rename(write_temp_file(do_write, **kw_args), filename) + shutil.move(write_temp_file(do_write, **kw_args), filename) def write_temp_file(do_write, mode=None, uidgid=None): fd, temporary_filename = tempfile.mkstemp() @@ -112,6 +120,38 @@ def write_temp_file(do_write, mode=None, uidgid=None): finally: f.close() return temporary_filename +# replace a target file with a new contents - checks for changes +# can handle chmod if requested +# can also remove resulting file if contents are void, if requested +# performs atomically: +# writes in a tmp file, which is then renamed (from sliverauth originally) +# returns True if a change occurred, or the file is deleted +def replace_file_with_string (target, new_contents, chmod=None, remove_if_empty=False): + try: + current=file(target).read() + except: + current="" + if current==new_contents: + # if turns out to be an empty string, and remove_if_empty is set, + # then make sure to trash the file if it exists + if remove_if_empty and not new_contents and os.path.isfile(target): + logger.verbose("tools.replace_file_with_string: removing file %s"%target) + try: os.unlink(target) + finally: return True + return False + # overwrite target file: create a temp in the same directory + path=os.path.dirname(target) or '.' + fd, name = tempfile.mkstemp('','repl',path) + os.write(fd,new_contents) + os.close(fd) + if os.path.exists(target): + os.unlink(target) + shutil.move(name,target) + if chmod: os.chmod(target,chmod) + return True + + +#################### # utilities functions to get (cached) information from the node # get node_id from /etc/planetlab/node_id and cache it @@ -125,29 +165,20 @@ def node_id(): _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") + sp=subprocess.Popen(["uname","-i"],stdout=subprocess.PIPE) + (_root_context_arch,_)=sp.communicate() + _root_context_arch=_root_context_arch.strip() return _root_context_arch +#################### class NMLock: def __init__(self, file): - logger.log("Lock %s initialized." % file, 2) + logger.log("tools: 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 @@ -155,8 +186,8 @@ class NMLock: def __del__(self): os.close(self.fd) def acquire(self): - logger.log("Lock acquired.", 2) + logger.log("tools: Lock acquired.", 2) fcntl.lockf(self.fd, fcntl.LOCK_SH) def release(self): - logger.log("Lock released.", 2) + logger.log("tools: Lock released.", 2) fcntl.lockf(self.fd, fcntl.LOCK_UN)