X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=tools.py;h=02e2ab9b7193b17f8f9aef7e9e6ccd3f9f65215a;hb=9e6b9c1ea9e020c55c85b433bac47231d63e9ffd;hp=c5d3e400495ca22f4920bbfa6ef102edf6704745;hpb=d3a3b2d3ea98e72183d1cb5497c38badaa0c5863;p=nodemanager.git diff --git a/tools.py b/tools.py index c5d3e40..02e2ab9 100644 --- a/tools.py +++ b/tools.py @@ -1,15 +1,15 @@ -# $Id$ -# $URL$ - """A few things that didn't seem to fit anywhere else.""" -import os +import os, os.path import pwd import tempfile import fcntl import errno import threading import subprocess +import shutil +import sys +import signal import logger @@ -60,7 +60,7 @@ 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 @@ -111,7 +111,7 @@ The return value is the pid of the other running process, or None otherwise.""" 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() @@ -123,25 +123,35 @@ def write_temp_file(do_write, mode=None, uidgid=None): return temporary_filename # replace a target file with a new contents - checks for changes -# return True if a change occurred, in which case -# chown/chmod settings should be taken care of -def replace_file_with_string (target, new_contents): +# 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="" - # xxx if verbose, report diffs... 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 - f=file(target,'w') - f.write(new_contents) - f.close() + # 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 -# not needed yet - should that unlink the new file ? -#def replace_file_with_file (target, new): -# return replace_file_with_string (target, file(new).read()) #################### # utilities functions to get (cached) information from the node @@ -183,3 +193,157 @@ class NMLock: def release(self): logger.log("tools: Lock released.", 2) fcntl.lockf(self.fd, fcntl.LOCK_UN) + +#################### +# Utilities for getting the IP address of a LXC/Openvswitch slice. Do this by +# running ifconfig inside of the slice's context. + +def get_sliver_process(slice_name, process_cmdline): + """ Utility function to find a process inside of an LXC sliver. Returns + (cgroup_fn, pid). cgroup_fn is the filename of the cgroup file for + the process, for example /proc/2592/cgroup. Pid is the process id of + the process. If the process is not found then (None, None) is returned. + """ + try: + cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name + output = os.popen(cmd).readlines() + except: + # the slice couldn't be found + logger.log("get_sliver_process: couldn't find slice %s" % slice_name) + return (None, None) + + cgroup_fn = None + pid = None + for e in output: + try: + l = e.rstrip() + path = l.split(':')[0] + comp = l.rsplit(':')[-1] + slice_name_check = comp.rsplit('/')[-1] + + if (slice_name_check == slice_name): + slice_path = path + pid = slice_path.split('/')[2] + cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00') + if (cmdline == process_cmdline): + cgroup_fn = slice_path + break + except: + break + + if (not cgroup_fn) or (not pid): + logger.log("get_sliver_process: process %s not running in slice %s" % (process_cmdline, slice_name)) + return (None, None) + + return (cgroup_fn, pid) + +def get_sliver_ifconfig(slice_name, device="eth0"): + """ return the output of "ifconfig" run from inside the sliver. + + side effects: adds "/usr/sbin" to sys.path + """ + + # See if setns is installed. If it's not then we're probably not running + # LXC. + if not os.path.exists("/usr/sbin/setns.so"): + return None + + # setns is part of lxcsu and is installed to /usr/sbin + if not "/usr/sbin" in sys.path: + sys.path.append("/usr/sbin") + import setns + + (cgroup_fn, pid) = get_sliver_process(slice_name, "/sbin/init") + if (not cgroup_fn) or (not pid): + return None + + path = '/proc/%s/ns/net'%pid + + result = None + try: + setns.chcontext(path) + + args = ["/sbin/ifconfig", device] + sub = subprocess.Popen(args, stderr = subprocess.PIPE, stdout = subprocess.PIPE) + sub.wait() + + if (sub.returncode != 0): + logger.log("get_slice_ifconfig: error in ifconfig: %s" % sub.stderr.read()) + + result = sub.stdout.read() + finally: + setns.chcontext("/proc/1/ns/net") + + return result + +def get_sliver_ip(slice_name): + ifconfig = get_sliver_ifconfig(slice_name) + if not ifconfig: + return None + + for line in ifconfig.split("\n"): + if "inet addr:" in line: + # example: ' inet addr:192.168.122.189 Bcast:192.168.122.255 Mask:255.255.255.0' + parts = line.strip().split() + if len(parts)>=2 and parts[1].startswith("addr:"): + return parts[1].split(":")[1] + + return None + +### this returns the kind of virtualization on the node +# either 'vs' or 'lxc' +# also caches it in /etc/planetlab/virt for next calls +# could be promoted to core nm if need be +virt_stamp="/etc/planetlab/virt" +def get_node_virt (): + try: + return file(virt_stamp).read().strip() + except: + pass + logger.log("Computing virt..") + try: + if subprocess.call ([ 'vserver', '--help' ]) ==0: virt='vs' + else: virt='lxc' + except: + virt='lxc' + with file(virt_stamp,"w") as f: + f.write(virt) + return virt + +### this return True or False to indicate that systemctl is present on that box +# cache result in memory as _has_systemctl +_has_systemctl=None +def has_systemctl (): + global _has_systemctl + if _has_systemctl is None: + _has_systemctl = (subprocess.call([ 'systemctl', '--help' ]) == 0) + return _has_systemctl + +# how to run a command in a slice +# now this is a painful matter +# the problem is with capsh that forces a bash command to be injected in its exec'ed command +# so because lxcsu uses capsh, you cannot exec anything else than bash +# bottom line is, what actually needs to be called is +# vs: vserver exec slicename command and its arguments +# lxc: lxcsu slicename "command and its arguments" +# which, OK, is no big deal as long as the command is simple enough, +# but do not stretch it with arguments that have spaces or need quoting as that will become a nightmare +def command_in_slice (slicename, argv): + virt=get_node_virt() + if virt=='vs': + return [ 'vserver', slicename, 'exec', ] + argv + elif virt=='lxc': + # wrap up argv in a single string for -c + return [ 'lxcsu', slicename, ] + [ " ".join(argv) ] + logger.log("command_in_slice: WARNING: could not find a valid virt") + return argv + +#################### +def init_signals (): + def handler (signum, frame): + logger.log("Received signal %d - exiting"%signum) + os._exit(1) + signal.signal(signal.SIGHUP,handler) + signal.signal(signal.SIGQUIT,handler) + signal.signal(signal.SIGINT,handler) + signal.signal(signal.SIGTERM,handler)