7 from argparse import ArgumentParser
9 drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
11 # can set to True here, but also use the -d option
15 output = os.popen('readelf -h %s 2>&1'%f).readlines()
16 classlines = [x for x in output if ('Class' in x.split(':')[0])]
18 c = line.split(':')[1]
24 raise Exception('Could not determine architecture')
27 output = os.popen('/bin/umount %s 2>&1'%fs_dir).read()
28 return ('device is busy' not in output)
31 parser = ArgumentParser()
32 parser.add_argument("-n", "--nonet",
33 action="store_true", dest="netns", default=False,
34 help="Don't enter network namespace")
35 parser.add_argument("-m", "--nomnt",
36 action="store_true", dest="mntns", default=False,
37 help="Don't enter mount namespace")
38 parser.add_argument("-p", "--nopid",
39 action="store_true", dest="pidns", default=False,
40 help="Don't enter pid namespace")
41 parser.add_argument("-r", "--root",
42 action="store_true", dest="root", default=False,
43 help="Enter as root: be careful")
44 parser.add_argument("-i","--internal",
45 action="store_true", dest="internal", default=False,
46 help="does *not* prepend '-- -c' to arguments - or invoke lxcsu-internal")
47 parser.add_argument("-d","--debug",
48 action='store_true', dest='debug', default=False,
50 parser.add_argument("-s","--nosliceuid",
51 action='store_true', dest="nosliceuid", default=False,
52 help="do not change to slice uid inside of slice")
53 parser.add_argument("-o","--noslicehome",
54 action='store_true', dest="noslicehome", default=False,
55 help="do not change to slice home directory inside of slice")
57 if os.path.exists("/etc/lxcsu_default"):
58 defaults = parser.parse_args(file("/etc/lxcsu_default","r").read().split())
59 parser.set_defaults(**defaults.__dict__)
61 parser.add_argument ("slice_name")
62 parser.add_argument ("command_to_run",nargs="*")
64 args = parser.parse_args()
65 slice_name=args.slice_name
67 # unless we run the symlink 'lxcsu-internal', or we specify the -i option, prepend '--' '-c'
68 if sys.argv[0].find('internal')>=0: args.internal=True
70 if len(args.command_to_run)>0 and (args.command_to_run[0] == "/sbin/service"):
71 # A quick hack to support nodemanager interfaces.py when restarting
72 # networking in a slice.
73 args.nosliceuid = True
77 # no command given: enter interactive shell
78 if not args.command_to_run: args.command_to_run=['/bin/sh']
79 args.command_to_run = [ '-c' ] + [" ".join(args.command_to_run)]
81 # support for either setting debug at the top of this file, or on the command-line
87 cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
88 output = os.popen(cmd).readlines()
90 print "Error finding slice %s"%slice_name
95 # provide a default as this is not always properly computed
101 path = l.split(':')[0]
102 comp = l.rsplit(':')[-1]
103 slice_name_check = comp.rsplit('/')[-1]
104 if debug: print "dealing with >%s<"%slice_name_check
106 if (slice_name_check == slice_name):
107 if debug: print "found %s"%slice_name
109 pid = slice_path.split('/')[2]
110 cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00')
111 if (cmdline == '/sbin/init') or (cmdline.startswith("init [")):
112 slice_spec = slice_path
113 arch = getarch('/proc/%s/exe'%pid)
118 print "BEG lxcsu - ignoring exception"
119 traceback.print_exc()
120 print "END lxcsu - ignoring exception"
123 if (not slice_spec or not pid):
124 print "Not started: %s"%slice_name
130 # Set sysctls specific to slice
132 sysctl_dir = '/etc/planetlab/vsys-attributes/%s'%slice_name
133 if (os.access(sysctl_dir,0)):
134 entries = os.listdir(sysctl_dir)
136 prefix = 'vsys_sysctl.'
137 if (e.startswith(prefix)):
138 sysctl_file = '/'.join([sysctl_dir,e])
139 sysctl_name = e[len(prefix):]
140 sysctl_val = open(sysctl_file).read()
141 sysctls.append((sysctl_file, sysctl_name, sysctl_val))
145 for subsystem in ['cpuset','memory','blkio']:
146 open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid()))
149 print "Error assigning resources: %s"%slice_name
153 open('/sys/fs/cgroup/cpuacct/system/libvirtd.service/libvirt/lxc/%s/tasks'%slice_name,'w').write(str(os.getpid()))
155 print "Error assigning cpuacct: %s" % slice_name
158 # If the slice is frozen, then we'll get an EBUSY when trying to write to the task
159 # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
160 # in this case to error out the shell. (an alternative would be to un-freeze it,
161 # add the task, and re-freeze it)
163 f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w')
164 f.write(str(os.getpid()))
165 # note: we need to call f.close() explicitly, or we'll get an exception in
166 # the object destructor, which will not be caught
169 print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name
172 setns.chcontext('/proc/%s/ns/uts'%pid)
173 setns.chcontext('/proc/%s/ns/ipc'%pid)
176 setns.chcontext('/proc/%s/ns/pid'%pid)
179 setns.chcontext('/proc/%s/ns/net'%pid)
182 setns.chcontext('/proc/%s/ns/mnt'%pid)
185 if (not os.access('/proc/self',0)):
189 for (sysctl_file, sysctl_name, sysctl_val) in sysctls:
190 for fn in ["/sbin/sysctl", "/usr/sbin/sysctl", "/bin/sysctl", "/usr/bin/sysctl"]:
191 if os.path.exists(fn):
192 os.system('%s -w %s=%s'%(fn, sysctl_name,sysctl_val))
195 print "Error: image does not have a sysctl binary"
197 # cgroups is not yet LXC-safe, so we need to use the coarse grained access control
198 # strategy of unmounting the filesystem
201 for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event']:
202 fs_path = '/sys/fs/cgroup/%s'%subsystem
203 if (not umount(fs_path)):
204 print "Error disabling cgroup access"
207 if (not umount('/sys/fs/cgroup')):
208 print "Error disabling cgroup access"
213 # capsh has a --user option starting with f14
214 # so if only for f12 we need to fake this one
216 # capsh.c does essentially the following when invoked with --user:
217 # pwd = getpwnam(user); ...
218 # ngroups = MAX_GROUPS;
219 # status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ...
220 # status = setgroups(ngroups, groups); ...
221 # status = setgid(pwd->pw_gid); ...
222 # status = setuid(pwd->pw_uid); ...
223 # however we cannot simulate that ourselves because if we did in this process then
224 # capsh could not be allowed to mess with caps any more
226 def getuid (slicename):
229 return pwd.getpwnam(slicename).pw_uid
234 cap_arg = '--drop='+drop_capabilities
237 if (args.nosliceuid):
238 # we still want to drop capabilities, but don't want to switch UIDs
239 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
241 uid = getuid (slice_name)
243 print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name
245 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--login',]+args.command_to_run
246 # once we can drop f12, it would be nicer to instead go for
247 # exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--','--login',]+args.command_to_run
249 exec_args = [arch,'/usr/sbin/capsh','--','--login']+args.command_to_run
251 os.environ['SHELL'] = '/bin/sh'
252 if os.path.exists('/etc/planetlab/lib/bind_public.so'):
253 os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
254 if not args.noslicehome:
255 os.environ['HOME'] = '/home/%s'%slice_name
256 os.chdir("/home/%s"%(slice_name))
257 if debug: print 'lxcsu:execv:','/usr/bin/setarch',exec_args
258 os.execv('/usr/bin/setarch',exec_args)
261 _,status = os.waitpid(pid,0)
262 exit(os.WEXITSTATUS(status))
264 if __name__ == '__main__':