X-Git-Url: http://git.onelab.eu/?p=lxc-userspace.git;a=blobdiff_plain;f=lxcsu;h=860f60ac07daaf9aaac4b3a63fe7d73331d9d6be;hp=560b9bfc75da4c5f8a172da7c6563d9d31c56583;hb=HEAD;hpb=f0b64f14ca70b2c56506ef50bbaed17cb09df34f diff --git a/lxcsu b/lxcsu index 560b9bf..860f60a 100755 --- a/lxcsu +++ b/lxcsu @@ -1,26 +1,297 @@ -#!/usr/bin/python +#!/usr/bin/python3 -import os import sys +import os +import setns +import pwd from argparse import ArgumentParser -LXCSU_INTERNAL='/usr/sbin/lxcsu-internal' -def main (): +# can set to True here, but also use the -d option +debug = False + + +def getarch(pid): + exe_filename = '/proc/%s/exe' % pid + output = os.popen('readelf -h %s 2>&1' % exe_filename).readlines() + classlines = [x for x in output if ('Class' in x.split(':')[0])] + line = classlines[0] + c = line.split(':')[1] + if ('ELF64' in c): + return 'x86_64' + elif ('ELF32' in c): + return 'i686' + else: + raise Exception('Could not determine architecture for pid %s' % pid) + + +def get_cgroup_subdirs_for_pid(pid): + cgroup_info_file = '/proc/%s/cgroup' % pid + cgroup_lines = open(cgroup_info_file).read().splitlines() + + subdirs = {} + for line in cgroup_lines: + try: + _, cgroup_name, subdir = line.split(':') + subdirs[cgroup_name] = subdir + except Exception as e: + print("Error reading cgroup info: %s" % str(e)) + pass + + return subdirs + + +def umount(fs_dir, opts=''): + output = os.popen('/bin/umount %s %s 2>&1' % (opts, fs_dir)).read() + return ('device is busy' not in output) + + +def main(): parser = ArgumentParser() - parser.add_argument ("slice_name") - parser.add_argument ("command_to_run",nargs="*") + parser.add_argument("-n", "--nonet", + action="store_true", dest="no_netns", default=False, + help="Don't enter network namespace") + parser.add_argument("-m", "--nomnt", + action="store_true", dest="no_mntns", default=False, + help="Don't enter mount namespace") + parser.add_argument("-p", "--nopid", + action="store_true", dest="no_pidns", default=False, + help="Don't enter pid namespace") + parser.add_argument("-r", "--root", + action="store_true", dest="root", default=False, + help="Enter as root: be careful") + parser.add_argument("-i", "--internal", + action="store_true", dest="internal", default=False, + help="does *not* prepend '-- -c' to arguments - or invoke lxcsu-internal") + parser.add_argument("-d", "--debug", + action='store_true', dest='debug', default=False, + help="debug option") + parser.add_argument("-s", "--nosliceuid", + action='store_true', dest="nosliceuid", default=False, + help="do not change to slice uid inside of slice") + parser.add_argument("-o", "--noslicehome", + action='store_true', dest="noslicehome", default=False, + help="do not change to slice home directory inside of slice") + + if os.path.exists("/etc/lxcsu_default"): + defaults = parser.parse_args( + file("/etc/lxcsu_default", "r").read().split()) + parser.set_defaults(**defaults.__dict__) + + parser.add_argument("slice_name") + parser.add_argument("command_to_run", nargs="*") + + args = parser.parse_args() + slice_name = args.slice_name + + # support for either setting debug at the top of this file, or on the command-line + if args.debug: + global debug + debug = True + + # somehow some older nodes won't be able to find the login name in /etc/passwd + # when this is done down the road, so compute slice_uid while in a safe env + # even though we don't use the slice_uid any more, this is still + # checked later on as a means to ensure existence of the slice account + try: + slice_uid = pwd.getpwnam(slice_name).pw_uid + except Exception as e: + if debug: + import traceback + print('error while computing slice_uid', e) + traceback.print_exc() + slice_uid = None + + # unless we run the symlink 'lxcsu-internal', or we specify the -i option, prepend '--' '-c' + if sys.argv[0].find('internal') >= 0: + args.internal = True + + if len(args.command_to_run) > 0 and (args.command_to_run[0] == "/sbin/service"): + # A quick hack to support nodemanager interfaces.py when restarting + # networking in a slice. + args.nosliceuid = True + + # plain lxcsu + if not args.internal: + # no command given: enter interactive shell + if not args.command_to_run: + args.command_to_run = ['/bin/sh'] + args.command_to_run = ['-c'] + [" ".join(args.command_to_run)] + + try: + cmd = '/usr/bin/virsh --connect lxc:/// domid %s' % slice_name + # convert to int as a minimal raincheck + driver_pid = int(os.popen(cmd).read().strip()) + # locate the pid for the - expected - single child, that would be the init for that VM + #init_pid = int(open("/proc/%s/task/%s/children"%(driver_pid,driver_pid)).read().strip()) + init_pid = int(os.popen('pgrep -P %s' % + driver_pid).readlines()[0].strip()) + # Thierry: I am changing the code below to use init_pid instead of driver_pid + # for the namespace handling features, that I was able to check + # I've left the other ones as they were, i.e. using driver_pid, but I suspect + # some should be changed as well + + except: + print("Domain %s not found" % slice_name) + exit(1) + + if not driver_pid or not init_pid: + print("Domain %s not started" % slice_name) + exit(1) + + if debug: + print("Found driver_pid", driver_pid, 'and init_pid=', init_pid) + # driver_pid is always x86_64, we need to look at the VM's init process here + arch = getarch(init_pid) + + # Set sysctls specific to slice + sysctls = [] + sysctl_dir = '/etc/planetlab/vsys-attributes/%s' % slice_name + if (os.access(sysctl_dir, 0)): + entries = os.listdir(sysctl_dir) + for e in entries: + prefix = 'vsys_sysctl.' + if (e.startswith(prefix)): + sysctl_file = '/'.join([sysctl_dir, e]) + sysctl_name = e[len(prefix):] + sysctl_val = open(sysctl_file).read() + sysctls.append((sysctl_file, sysctl_name, sysctl_val)) + + # xxx probably init_pid here too + subdirs = get_cgroup_subdirs_for_pid(driver_pid) + sysfs_root = '/sys/fs/cgroup' + + # If the slice is frozen, then we'll get an EBUSY when trying to write to the task + # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best + # in this case to error out the shell. (an alternative would be to un-freeze it, + # add the task, and re-freeze it) + # Enter cgroups + current_cgroup = '' + for subsystem in ['cpuset', 'memory', 'blkio', 'cpuacct', 'cpuacct,cpu', 'freezer']: + try: + current_cgroup = subsystem + + # There seems to be a bug in the cgroup schema: cpuacct,cpu can become cpu,cpuacct + # We need to handle both + task_path_alt = None + try: + subsystem_comps = subsystem.split(',') + subsystem_comps.reverse() + subsystem_alt = ','.join(subsystem_comps) + tasks_path_alt = [sysfs_root, subsystem_alt, + subdirs[subsystem], 'tasks'] + except Exception as e: + pass + + tasks_path = [sysfs_root, subsystem, subdirs[subsystem], 'tasks'] + tasks_path_str = '/'.join(tasks_path) + + try: + f = open(tasks_path_str, 'w') + except: + tasks_path_alt_str = '/'.join(tasks_path_alt) + f = open(tasks_path_alt_str, 'w') + + f.write(str(os.getpid())) + if (subsystem == 'freezer'): + f.close() + + except Exception as e: + if (subsystem not in subdirs): + pass + else: + if debug: + print(e) + print("Error assigning cgroup %s (pid=%s) for slice %s" % + (current_cgroup, driver_pid, slice_name)) + exit(1) + + def chcontext(path): + retcod = setns.chcontext(path) + if retcod != 0: + print('WARNING - setns(%s)=>%s (ignored)' % (path, retcod)) + return retcod + + # Use init_pid and not driver_pid to locate reference namespaces + ref_ns = "/proc/%s/ns/" % init_pid + + if True: + chcontext(ref_ns+'uts') + if True: + chcontext(ref_ns+'ipc') + + if (not args.no_pidns): + chcontext(ref_ns+'pid') + if (not args.no_netns): + chcontext(ref_ns+'net') + if (not args.no_mntns): + chcontext(ref_ns+'mnt') + + proc_mounted = False + if (not os.access('/proc/self', 0)): + proc_mounted = True + setns.proc_mount() + + for (sysctl_file, sysctl_name, sysctl_val) in sysctls: + for fn in ["/sbin/sysctl", "/usr/sbin/sysctl", "/bin/sysctl", "/usr/bin/sysctl"]: + if os.path.exists(fn): + os.system('%s -w %s=%s >/dev/null 2>&1' % + (fn, sysctl_name, sysctl_val)) + break + else: + print("Error: image does not have a sysctl binary") + + # cgroups is not yet LXC-safe, so we need to use the coarse grained access control + # strategy of unmounting the filesystem + + umount_result = True + for subsystem in ['cpuset', 'cpu,cpuacct', 'memory', 'devices', 'freezer', 'net_cls', 'blkio', 'perf_event', 'systemd']: + fs_path = '/sys/fs/cgroup/%s' % subsystem + if (not umount(fs_path, '-l')): + print('WARNING - umount failed (ignored) with path=', fs_path) + pass + # Leaving these comments for historical reference + # print "Error disabling cgroup access" + # exit(1) - Don't need this because failure here implies failure in the call to umount /sys/fs/cgroup + + if (not umount('/sys/fs/cgroup')): + print("Error disabling cgroup access") + exit(1) + + fork_pid = os.fork() - options = parser.parse_args() - slice_name=options.slice_name - commands = options.command_to_run - if (not commands): - commands = ['/bin/sh'] + if (fork_pid == 0): + if (not args.root): + setns.drop_caps() + if (args.nosliceuid): + # we still want to drop capabilities, but don't want to switch UIDs + exec_args = [arch, '/bin/sh', '--login', ]+args.command_to_run + else: + if not slice_uid: + print("lxcsu could not spot %s in /etc/passwd - exiting" % + slice_name) + exit(1) + exec_args = [arch, '/usr/bin/sudo', '-u', slice_name, + '/bin/sh', '--login', ]+args.command_to_run +# once we can drop f12, it would be nicer to instead go for +# exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--login',]+args.command_to_run + else: + exec_args = [arch, '/bin/sh', '--login']+args.command_to_run + os.environ['SHELL'] = '/bin/sh' + if os.path.exists('/etc/planetlab/lib/bind_public.so'): + os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so' + if not args.noslicehome: + os.environ['HOME'] = '/home/%s' % slice_name + os.chdir("/home/%s" % (slice_name)) + if debug: + print('lxcsu:execv:', '/usr/bin/setarch', exec_args) + os.execv('/usr/bin/setarch', exec_args) + else: + setns.proc_umount() + _, status = os.waitpid(fork_pid, 0) + exit(os.WEXITSTATUS(status)) - exec_args = [LXCSU_INTERNAL,slice_name,'--'] - exec_args+=commands - os.execv(LXCSU_INTERNAL,exec_args) if __name__ == '__main__': main()