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')
26 def umount(fs_dir, opts=''):
27 output = os.popen('/bin/umount %s %s 2>&1'%(opts, 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 = '/usr/bin/virsh domid %s'%slice_name
88 pidnum = int(os.popen(cmd).read().rstrip())
90 print "Error finding slice %s"%slice_name
94 cmdline = open('/proc/%s/cmdline'%pidnum).read().rstrip('\n\x00')
95 arch = getarch('/proc/%s/exe'%pid)
98 print "Not started: %s"%slice_name
104 # Set sysctls specific to slice
106 sysctl_dir = '/etc/planetlab/vsys-attributes/%s'%slice_name
107 if (os.access(sysctl_dir,0)):
108 entries = os.listdir(sysctl_dir)
110 prefix = 'vsys_sysctl.'
111 if (e.startswith(prefix)):
112 sysctl_file = '/'.join([sysctl_dir,e])
113 sysctl_name = e[len(prefix):]
114 sysctl_val = open(sysctl_file).read()
115 sysctls.append((sysctl_file, sysctl_name, sysctl_val))
119 for subsystem in ['cpuset','memory','blkio']:
120 open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid()))
123 print "Error assigning resources: %s"%slice_name
127 open('/sys/fs/cgroup/cpuacct/system/libvirtd.service/libvirt/lxc/%s/tasks'%slice_name,'w').write(str(os.getpid()))
129 print "Error assigning cpuacct: %s" % slice_name
132 # If the slice is frozen, then we'll get an EBUSY when trying to write to the task
133 # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
134 # in this case to error out the shell. (an alternative would be to un-freeze it,
135 # add the task, and re-freeze it)
137 f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w')
138 f.write(str(os.getpid()))
139 # note: we need to call f.close() explicitly, or we'll get an exception in
140 # the object destructor, which will not be caught
143 print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name
146 setns.chcontext('/proc/%s/ns/uts'%pid)
147 setns.chcontext('/proc/%s/ns/ipc'%pid)
150 setns.chcontext('/proc/%s/ns/pid'%pid)
153 setns.chcontext('/proc/%s/ns/net'%pid)
156 setns.chcontext('/proc/%s/ns/mnt'%pid)
159 if (not os.access('/proc/self',0)):
163 for (sysctl_file, sysctl_name, sysctl_val) in sysctls:
164 for fn in ["/sbin/sysctl", "/usr/sbin/sysctl", "/bin/sysctl", "/usr/bin/sysctl"]:
165 if os.path.exists(fn):
166 os.system('%s -w %s=%s >/dev/null 2>&1'%(fn, sysctl_name,sysctl_val))
169 print "Error: image does not have a sysctl binary"
171 # cgroups is not yet LXC-safe, so we need to use the coarse grained access control
172 # strategy of unmounting the filesystem
175 for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event','systemd']:
176 fs_path = '/sys/fs/cgroup/%s'%subsystem
177 if (not umount(fs_path,'-l')):
179 # Leaving these comments for historical reference
180 #print "Error disabling cgroup access"
181 #exit(1) - Don't need this because failure here implies failure in the call to umount /sys/fs/cgroup
183 if (not umount('/sys/fs/cgroup')):
184 print "Error disabling cgroup access"
189 # capsh has a --user option starting with f14
190 # so if only for f12 we need to fake this one
192 # capsh.c does essentially the following when invoked with --user:
193 # pwd = getpwnam(user); ...
194 # ngroups = MAX_GROUPS;
195 # status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ...
196 # status = setgroups(ngroups, groups); ...
197 # status = setgid(pwd->pw_gid); ...
198 # status = setuid(pwd->pw_uid); ...
199 # however we cannot simulate that ourselves because if we did in this process then
200 # capsh could not be allowed to mess with caps any more
202 def getuid (slicename):
205 return pwd.getpwnam(slicename).pw_uid
210 cap_arg = '--drop='+drop_capabilities
213 if (args.nosliceuid):
214 # we still want to drop capabilities, but don't want to switch UIDs
215 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
217 uid = getuid (slice_name)
219 print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name
221 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--login',]+args.command_to_run
222 # once we can drop f12, it would be nicer to instead go for
223 # exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--','--login',]+args.command_to_run
225 exec_args = [arch,'/usr/sbin/capsh','--','--login']+args.command_to_run
227 os.environ['SHELL'] = '/bin/sh'
228 if os.path.exists('/etc/planetlab/lib/bind_public.so'):
229 os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
230 if not args.noslicehome:
231 os.environ['HOME'] = '/home/%s'%slice_name
232 os.chdir("/home/%s"%(slice_name))
233 if debug: print 'lxcsu:execv:','/usr/bin/setarch',exec_args
234 os.execv('/usr/bin/setarch',exec_args)
237 _,status = os.waitpid(pid,0)
238 exit(os.WEXITSTATUS(status))
240 if __name__ == '__main__':