X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lxcsu;h=3f22cc3c1d97e4bafd27fbad3fbe424952d2195f;hb=f350306fc4725bd74aa7a8ddc42d9ef8d29ec15b;hp=20381ad6dede9b2c03680351c788e3f39738af82;hpb=c587cef8affadec1b4307a58d7b2b5695471d12f;p=lxc-userspace.git diff --git a/lxcsu b/lxcsu index 20381ad..3f22cc3 100644 --- a/lxcsu +++ b/lxcsu @@ -1,14 +1,16 @@ #!/usr/bin/python - -import setns -import os import sys +import os +import setns -from optparse import OptionParser +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])] @@ -23,30 +25,47 @@ def getarch(f): def umount(fs_dir): output = os.popen('/bin/umount %s 2>&1'%fs_dir).read() - return ('device is busy' not in fs_dir) + return ('device is busy' not in output) def main (): - parser = OptionParser() - parser.add_option("-n", "--nonet", - action="store_true", dest="netns", default=False, - help="Don't enter network namespace") - parser.add_option("-m", "--nomnt", - action="store_true", dest="mntns", default=False, - help="Don't enter mount namespace") - parser.add_option("-p", "--nopid", - action="store_true", dest="pidns", default=False, - help="Don't enter pid namespace") - parser.add_option("-r", "--root", - action="store_true", dest="root", default=False, - help="Enter as root: be careful") - - (options, args) = parser.parse_args() - - try: - slice_name = args[0] - except IndexError: - print "You must specify a vm name" - exit(1) + 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 @@ -57,8 +76,8 @@ def main (): slice_spec = None - # xxx fixme xxx - provide a default as this is not always properly computed - arch = 'x86_64' + # provide a default as this is not always properly computed + arch = None for e in output: try: @@ -66,22 +85,45 @@ def main (): 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'): + if (cmdline == '/sbin/init') or (cmdline.startswith("init [")): slice_spec = slice_path arch = getarch('/proc/%s/exe'%pid) break - except: - 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']: @@ -113,17 +155,32 @@ def main (): setns.chcontext('/proc/%s/ns/uts'%pid) setns.chcontext('/proc/%s/ns/ipc'%pid) + + if (not args.pidns): + setns.chcontext('/proc/%s/ns/pid'%pid) - if (not options.netns): + if (not args.netns): setns.chcontext('/proc/%s/ns/net'%pid) - if (not options.mntns): - open('/proc/lxcsu','w').write(pid) - - if (not options.pidns): - open('/proc/pidsu','w').write(pid) - - # cgroups is not yet LXC-safe, so we need to use the course grained access control + 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 @@ -139,17 +196,48 @@ def main (): 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 options.root): - exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+args[1:] + 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[1:] + 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))