X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lxcsu;h=3f22cc3c1d97e4bafd27fbad3fbe424952d2195f;hb=f350306fc4725bd74aa7a8ddc42d9ef8d29ec15b;hp=b435b25e72cf54ff33ccea2c669fcf8d60ffd9ef;hpb=85e4e9d38a2670da7c66178d629a71d2f3caa901;p=lxc-userspace.git diff --git a/lxcsu b/lxcsu index b435b25..3f22cc3 100644 --- a/lxcsu +++ b/lxcsu @@ -1,103 +1,245 @@ #!/usr/bin/python - -import setns -import os import sys +import os +import setns -#from optparse import OptionParser - -drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'.split(',') - -""" -parser = OptionParser() -parser.add_option("-n", "--net", - action="store_true", dest="netns", default=False, - help="Enter network namespace") -parser.add_option("-m", "--mnt", - action="store_true", dest="mntns", default=False, - help="Enter mount namespace") -parser.add_option("-p", "--pid", - action="store_true", dest="pidns", default=False, - help="Enter pid namespace") - -(options, args) = parser.parse_args() -""" -args = sys.argv[1:] - -try: - slice_name = args[0] -except IndexError: - print "You must specify a vm name" - exit(1) - -try: - cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name - output = os.popen(cmd).readlines() -except: - print "Error finding slice %s"%slice_name - exit(1) - -slice_spec = 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 == '/sbin/init'): - slice_spec = slice_path - break - except: - break - -if (not slice_spec or not pid): - print "Not started: %s"%slice_name - exit(1) - -# Enter cgroups -try: - for subsystem in ['cpuset','memory','blkio']: - open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid())) - -except: - print "Error assigning resources: %s"%slice_name - exit(1) - -# 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) -try: - f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w') - f.write(str(os.getpid())) - # note: we need to call f.close() explicitly, or we'll get an exception in - # the object destructor, which will not be caught - f.close() -except: - print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name - exit(1) - -r1 = setns.chcontext('/proc/%s/ns/uts'%pid) - -print pid - -r2 = setns.chcontext('/proc/%s/ns/ipc'%pid) -r3 = setns.chcontext('/proc/%s/ns/net'%pid) - -open('/proc/lxcsu','w').write(pid) -open('/proc/pidsu','w').write(pid) - -pid = os.fork() - -cap_args = map(lambda c:'--drop='+c, drop_capabilities) +from argparse import ArgumentParser + +drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module' + +# can set to True here, but also use the -d option +debug = False + +def getarch(f): + output = os.popen('readelf -h %s 2>&1'%f).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') + +def umount(fs_dir): + output = os.popen('/bin/umount %s 2>&1'%fs_dir).read() + return ('device is busy' not in output) + +def main (): + parser = ArgumentParser() + parser.add_argument("-n", "--nonet", + action="store_true", dest="netns", default=False, + help="Don't enter network namespace") + parser.add_argument("-m", "--nomnt", + action="store_true", dest="mntns", default=False, + help="Don't enter mount namespace") + parser.add_argument("-p", "--nopid", + action="store_true", dest="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 ("slice_name") + parser.add_argument ("command_to_run",nargs="*") + + args = parser.parse_args() + slice_name=args.slice_name + + # 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 + + # 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' ] + args.command_to_run + + # support for either setting debug at the top of this file, or on the command-line + if args.debug: + global debug + debug=True + + try: + cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name + output = os.popen(cmd).readlines() + except: + print "Error finding slice %s"%slice_name + exit(1) + + slice_spec = None + + # provide a default as this is not always properly computed + arch = None + + for e in output: + try: + l = e.rstrip() + path = l.split(':')[0] + comp = l.rsplit(':')[-1] + slice_name_check = comp.rsplit('/')[-1] + if debug: print "dealing with >%s<"%slice_name_check + + if (slice_name_check == slice_name): + if debug: print "found %s"%slice_name + slice_path = path + pid = slice_path.split('/')[2] + cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00') + if (cmdline == '/sbin/init') or (cmdline.startswith("init [")): + slice_spec = slice_path + arch = getarch('/proc/%s/exe'%pid) + break + except Exception,e: + if debug: + import traceback + print "BEG lxcsu - ignoring exception" + traceback.print_exc() + print "END lxcsu - ignoring exception" + pass + + if (not slice_spec or not pid): + print "Not started: %s"%slice_name + exit(1) + + if arch is None: + arch = 'x86_64' + + # 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)) + + # Enter cgroups + try: + for subsystem in ['cpuset','memory','blkio']: + open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid())) + + except: + print "Error assigning resources: %s"%slice_name + exit(1) + + try: + open('/sys/fs/cgroup/cpuacct/system/libvirtd.service/libvirt/lxc/%s/tasks'%slice_name,'w').write(str(os.getpid())) + except: + print "Error assigning cpuacct: %s" % slice_name + exit(1) + + # 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) + try: + f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w') + f.write(str(os.getpid())) + # note: we need to call f.close() explicitly, or we'll get an exception in + # the object destructor, which will not be caught + f.close() + except: + print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name + exit(1) + + setns.chcontext('/proc/%s/ns/uts'%pid) + setns.chcontext('/proc/%s/ns/ipc'%pid) -if (pid == 0): - os.execv('/usr/sbin/capsh',cap_args+['--','--login']+args[1:]) -else: - os.waitpid(pid,0) + if (not args.pidns): + setns.chcontext('/proc/%s/ns/pid'%pid) + + if (not args.netns): + setns.chcontext('/proc/%s/ns/net'%pid) + + if (not args.mntns): + setns.chcontext('/proc/%s/ns/mnt'%pid) + + 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("mount -o remount,rw none /proc/sys") + os.system('%s -w %s=%s'%(fn, sysctl_name,sysctl_val)) + os.system("mount -o remount,ro none /proc/sys") + 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']: + fs_path = '/sys/fs/cgroup/%s'%subsystem + if (not umount(fs_path)): + print "Error disabling cgroup access" + exit(1) + + if (not umount('/sys/fs/cgroup')): + print "Error disabling cgroup access" + exit(1) + + pid = os.fork() + + # capsh has a --user option starting with f14 + # so if only for f12 we need to fake this one + # + # capsh.c does essentially the following when invoked with --user: + # pwd = getpwnam(user); ... + # ngroups = MAX_GROUPS; + # status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ... + # status = setgroups(ngroups, groups); ... + # status = setgid(pwd->pw_gid); ... + # status = setuid(pwd->pw_uid); ... + # however we cannot simulate that ourselves because if we did in this process then + # capsh could not be allowed to mess with caps any more + + def getuid (slicename): + import pwd + try: + return pwd.getpwnam(slicename).pw_uid + except: + return + + if (pid == 0): + cap_arg = '--drop='+drop_capabilities + + if (not args.root): + uid = getuid (slice_name) + if not uid: + print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name + exit(1) + exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--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,'/usr/sbin/capsh','--','--login']+args.command_to_run + + os.environ['SHELL'] = '/bin/sh' + os.environ['HOME'] = '/home/%s'%slice_name + os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so' + 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(pid,0) + exit(os.WEXITSTATUS(status)) + +if __name__ == '__main__': + main()