8 from argparse import ArgumentParser
10 drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
13 output = os.popen('readelf -h %s 2>&1'%f).readlines()
14 classlines = [x for x in output if ('Class' in x.split(':')[0])]
16 c = line.split(':')[1]
22 raise Exception('Could not determine architecture')
25 output = os.popen('/bin/umount %s 2>&1'%fs_dir).read()
26 return ('device is busy' not in fs_dir)
29 parser = ArgumentParser()
30 parser.add_argument("-n", "--nonet",
31 action="store_true", dest="netns", default=False,
32 help="Don't enter network namespace")
33 parser.add_argument("-m", "--nomnt",
34 action="store_true", dest="mntns", default=False,
35 help="Don't enter mount namespace")
36 parser.add_argument("-p", "--nopid",
37 action="store_true", dest="pidns", default=False,
38 help="Don't enter pid namespace")
39 parser.add_argument("-r", "--root",
40 action="store_true", dest="root", default=False,
41 help="Enter as root: be careful")
42 parser.add_argument ("slice",dest="slice_name",nargs=1)
44 options = parser.parse_args()
45 slice_name=options.slice_name
48 cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
49 output = os.popen(cmd).readlines()
51 print "Error finding slice %s"%slice_name
56 # xxx fixme xxx - provide a default as this is not always properly computed
62 path = l.split(':')[0]
63 comp = l.rsplit(':')[-1]
64 slice_name_check = comp.rsplit('/')[-1]
66 if (slice_name_check == slice_name):
68 pid = slice_path.split('/')[2]
69 cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00')
70 if (cmdline == '/sbin/init'):
71 slice_spec = slice_path
72 arch = getarch('/proc/%s/exe'%pid)
77 if (not slice_spec or not pid):
78 print "Not started: %s"%slice_name
83 for subsystem in ['cpuset','memory','blkio']:
84 open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid()))
87 print "Error assigning resources: %s"%slice_name
91 open('/sys/fs/cgroup/cpuacct/system/libvirtd.service/libvirt/lxc/%s/tasks'%slice_name,'w').write(str(os.getpid()))
93 print "Error assigning cpuacct: %s" % slice_name
96 # If the slice is frozen, then we'll get an EBUSY when trying to write to the task
97 # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
98 # in this case to error out the shell. (an alternative would be to un-freeze it,
99 # add the task, and re-freeze it)
101 f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w')
102 f.write(str(os.getpid()))
103 # note: we need to call f.close() explicitly, or we'll get an exception in
104 # the object destructor, which will not be caught
107 print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name
110 setns.chcontext('/proc/%s/ns/uts'%pid)
111 setns.chcontext('/proc/%s/ns/ipc'%pid)
113 if (not options.netns):
114 setns.chcontext('/proc/%s/ns/net'%pid)
116 if (not options.mntns):
117 open('/proc/lxcsu','w').write(pid)
119 if (not options.pidns):
120 open('/proc/pidsu','w').write(pid)
122 # cgroups is not yet LXC-safe, so we need to use the course grained access control
123 # strategy of unmounting the filesystem
126 for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event']:
127 fs_path = '/sys/fs/cgroup/%s'%subsystem
128 if (not umount(fs_path)):
129 print "Error disabling cgroup access"
132 if (not umount('/sys/fs/cgroup')):
133 print "Error disabling cgroup access"
139 cap_arg = '--drop='+drop_capabilities
141 if (not options.root):
142 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+args[1:]
144 exec_args = [arch,'/usr/sbin/capsh','--','--login']+args[1:]
146 os.environ['SHELL'] = '/bin/sh'
147 os.execv('/usr/bin/setarch',exec_args)
149 _,status = os.waitpid(pid,0)
150 exit(os.WEXITSTATUS(status))
152 if __name__ == '__main__':