From c587cef8affadec1b4307a58d7b2b5695471d12f Mon Sep 17 00:00:00 2001 From: Thierry Parmentelat Date: Wed, 29 May 2013 15:40:25 +0200 Subject: [PATCH] added a main function --- lxcsu | 236 +++++++++++++++++++++++++++++----------------------------- 1 file changed, 120 insertions(+), 116 deletions(-) diff --git a/lxcsu b/lxcsu index 97600cf..20381ad 100644 --- a/lxcsu +++ b/lxcsu @@ -25,129 +25,133 @@ def umount(fs_dir): output = os.popen('/bin/umount %s 2>&1'%fs_dir).read() return ('device is busy' not in fs_dir) -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) - -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 - -# xxx fixme xxx - provide a default as this is not always properly computed -arch = 'x86_64' - -for e 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) + + 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 + + # xxx fixme xxx - provide a default as this is not always properly computed + arch = 'x86_64' + + 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 + arch = getarch('/proc/%s/exe'%pid) + break + except: + break + + if (not slice_spec or not pid): + print "Not started: %s"%slice_name + exit(1) + + # Enter cgroups 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 - arch = getarch('/proc/%s/exe'%pid) - break + for subsystem in ['cpuset','memory','blkio']: + open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid())) + 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) - -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 options.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 -# 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 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 options.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 + # 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) -if (not umount('/sys/fs/cgroup')): - print "Error disabling cgroup access" - exit(1) + pid = os.fork() -pid = os.fork() + if (pid == 0): + cap_arg = '--drop='+drop_capabilities -if (pid == 0): - cap_arg = '--drop='+drop_capabilities + if (not options.root): + exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+args[1:] + else: + exec_args = [arch,'/usr/sbin/capsh','--','--login']+args[1:] - if (not options.root): - exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+args[1:] + os.environ['SHELL'] = '/bin/sh' + os.execv('/usr/bin/setarch',exec_args) else: - exec_args = [arch,'/usr/sbin/capsh','--','--login']+args[1:] + _,status = os.waitpid(pid,0) + exit(os.WEXITSTATUS(status)) - os.environ['SHELL'] = '/bin/sh' - os.execv('/usr/bin/setarch',exec_args) -else: - _,status = os.waitpid(pid,0) - exit(os.WEXITSTATUS(status)) +if __name__ == '__main__': + main() -- 2.43.0