From e0abda420d460dc1a717193b2eabc564bd81feb1 Mon Sep 17 00:00:00 2001 From: Thierry Parmentelat Date: Mon, 8 Jul 2013 21:19:33 +0200 Subject: [PATCH] move back to a single source file (lxcsu) with a -i/--internal option, and an lxcsu-internal symlink --- lxcsu | 231 ++++++++++++++++++++++++++++++++++++++++++++++--- lxcsu-internal | 226 +---------------------------------------------- 2 files changed, 222 insertions(+), 235 deletions(-) mode change 100755 => 120000 lxcsu-internal diff --git a/lxcsu b/lxcsu index 742fc83..5756162 100755 --- a/lxcsu +++ b/lxcsu @@ -1,27 +1,238 @@ #!/usr/bin/python -import os import sys +import os +import setns from argparse import ArgumentParser -LXCSU_INTERNAL='/usr/sbin/lxcsu-internal' +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="*") - options = parser.parse_args() - slice_name=options.slice_name - commands = options.command_to_run - if (not commands): - commands = ['/bin/sh'] + 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 + 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() + os.system('sysctl -w %s=%s'%(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 (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() + + + + # 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-internal 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 - exec_args = [LXCSU_INTERNAL,slice_name,'--','-c'] - exec_args+=commands - os.execv(LXCSU_INTERNAL,exec_args) + 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)) + print 'lxcsu-internal: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() diff --git a/lxcsu-internal b/lxcsu-internal deleted file mode 100755 index e303583..0000000 --- a/lxcsu-internal +++ /dev/null @@ -1,225 +0,0 @@ -#!/usr/bin/python - - -import setns -import os - -from argparse import ArgumentParser - -drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module' - -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("-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 - # 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) - - 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 - 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() - os.system('sysctl -w %s=%s'%(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 (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() - - - - # cgroups is not yet LXC-safe, so we need to use the course 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-internal 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-internal: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() diff --git a/lxcsu-internal b/lxcsu-internal new file mode 120000 index 0000000..2e16c03 --- /dev/null +++ b/lxcsu-internal @@ -0,0 +1 @@ +lxcsu \ No newline at end of file -- 2.43.0