X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lxcsu;h=c1ad9d139e2ded1e18e67af5d3a3abd8108be7f9;hb=bc916290e9e64b040b6c063b733c5fc63efca7c6;hp=83f1144bf752c92bd830b872fb8feb011acd59ea;hpb=7cee96a4f07f95ee9660b954473ecf25f602c6a0;p=lxc-userspace.git diff --git a/lxcsu b/lxcsu index 83f1144..c1ad9d1 100755 --- a/lxcsu +++ b/lxcsu @@ -1,19 +1,18 @@ #!/usr/bin/python - -import setns -import os import sys +import os +import setns 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() - if debug: print "readelf output %s lines"%len(output) classlines = [x for x in output if ('Class' in x.split(':')[0])] line = classlines[0] c = line.split(':')[1] @@ -26,7 +25,7 @@ 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 = ArgumentParser() @@ -42,21 +41,51 @@ def main (): 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="*") - options = parser.parse_args() - slice_name=options.slice_name - global debug - debug=options.debug + 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 + + 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)] + + # 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() - if debug: print "output of grep freezer has %s lines"%len(output) except: print "Error finding slice %s"%slice_name exit(1) @@ -79,10 +108,9 @@ def main (): 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) - if debug: print "setting arch",arch break except Exception,e: if debug: @@ -98,7 +126,19 @@ def main (): if arch is None: arch = 'x86_64' - if debug: print "WARNING: setting arch to default 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: @@ -131,17 +171,30 @@ 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 args.mntns): + setns.chcontext('/proc/%s/ns/mnt'%pid) - if (not options.pidns): - open('/proc/pidsu','w').write(pid) + proc_mounted = False + if (not os.access('/proc/self',0)): + proc_mounted = True + setns.proc_mount() - # cgroups is not yet LXC-safe, so we need to use the course grained access control + 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'%(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 @@ -157,20 +210,54 @@ 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']+options.command_to_run + if (not args.root): + if (args.nosliceuid): + # we still want to drop capabilities, but don't want to switch UIDs + exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run + else: + 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']+options.command_to_run + exec_args = [arch,'/usr/sbin/capsh','--','--login']+args.command_to_run - if debug: - print "exec'ing" - for arg in exec_args: print ">%s<"%arg 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(pid,0) exit(os.WEXITSTATUS(status))