8 from argparse import ArgumentParser
10 drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
12 # can set to True here, but also use the -d option
16 output = os.popen('readelf -h %s 2>&1'%f).readlines()
17 classlines = [x for x in output if ('Class' in x.split(':')[0])]
19 c = line.split(':')[1]
25 raise Exception('Could not determine architecture')
27 def get_cgroup_subdirs_for_pid(pid):
28 cgroup_info_file = '/proc/%s/cgroup'%pid
29 cgroup_lines = open(cgroup_info_file).read().splitlines()
32 for line in cgroup_lines:
34 _, cgroup_name, subdir = line.split(':')
35 subdirs[cgroup_name] = subdir
37 print "Error reading cgroup info: %s"%str(e)
43 def umount(fs_dir, opts=''):
44 output = os.popen('/bin/umount %s %s 2>&1'%(opts, fs_dir)).read()
45 return ('device is busy' not in output)
48 parser = ArgumentParser()
49 parser.add_argument("-n", "--nonet",
50 action="store_true", dest="no_netns", default=False,
51 help="Don't enter network namespace")
52 parser.add_argument("-m", "--nomnt",
53 action="store_true", dest="no_mntns", default=False,
54 help="Don't enter mount namespace")
55 parser.add_argument("-p", "--nopid",
56 action="store_true", dest="no_pidns", default=False,
57 help="Don't enter pid namespace")
58 parser.add_argument("-r", "--root",
59 action="store_true", dest="root", default=False,
60 help="Enter as root: be careful")
61 parser.add_argument("-i","--internal",
62 action="store_true", dest="internal", default=False,
63 help="does *not* prepend '-- -c' to arguments - or invoke lxcsu-internal")
64 parser.add_argument("-d","--debug",
65 action='store_true', dest='debug', default=False,
67 parser.add_argument("-s","--nosliceuid",
68 action='store_true', dest="nosliceuid", default=False,
69 help="do not change to slice uid inside of slice")
70 parser.add_argument("-o","--noslicehome",
71 action='store_true', dest="noslicehome", default=False,
72 help="do not change to slice home directory inside of slice")
74 if os.path.exists("/etc/lxcsu_default"):
75 defaults = parser.parse_args(file("/etc/lxcsu_default","r").read().split())
76 parser.set_defaults(**defaults.__dict__)
78 parser.add_argument ("slice_name")
79 parser.add_argument ("command_to_run",nargs="*")
81 args = parser.parse_args()
82 slice_name=args.slice_name
84 # unless we run the symlink 'lxcsu-internal', or we specify the -i option, prepend '--' '-c'
85 if sys.argv[0].find('internal')>=0: args.internal=True
87 if len(args.command_to_run)>0 and (args.command_to_run[0] == "/sbin/service"):
88 # A quick hack to support nodemanager interfaces.py when restarting
89 # networking in a slice.
90 args.nosliceuid = True
94 # no command given: enter interactive shell
95 if not args.command_to_run: args.command_to_run=['/bin/sh']
96 args.command_to_run = [ '-c' ] + [" ".join(args.command_to_run)]
98 # support for either setting debug at the top of this file, or on the command-line
104 cmd = '/usr/bin/virsh --connect lxc:/// domid %s'%slice_name
105 # convert to int as a minimal raincheck
106 driver_pid = int(os.popen(cmd).read().strip())
107 # locate the pid for the - expected - single child, that would be the init for that VM
108 init_pid = int(open("/proc/%s/task/%s/children"%(driver_pid,driver_pid)).read().strip())
109 # Thierry: I am changing the code below to use child_pid instead of driver_pid
110 # for the namespace handling features, that I was able to check
111 # I've left the other ones as they were, i.e. using driver_pid, but I suspect
112 # they chould be changed as well
115 print "Domain %s not found"%slice_name
118 if not driver_pid or not init_pid:
119 print "Domain %s not started"%slice_name
122 if debug: print "Found driver_pid",driver_pid,'and init_pid=',init_pid
123 # xxx probably init_pid here too
124 arch = getarch('/proc/%s/exe'%driver_pid)
126 # Set sysctls specific to slice
128 sysctl_dir = '/etc/planetlab/vsys-attributes/%s'%slice_name
129 if (os.access(sysctl_dir,0)):
130 entries = os.listdir(sysctl_dir)
132 prefix = 'vsys_sysctl.'
133 if (e.startswith(prefix)):
134 sysctl_file = '/'.join([sysctl_dir,e])
135 sysctl_name = e[len(prefix):]
136 sysctl_val = open(sysctl_file).read()
137 sysctls.append((sysctl_file, sysctl_name, sysctl_val))
139 # xxx probably init_pid here too
140 subdirs = get_cgroup_subdirs_for_pid(driver_pid)
141 sysfs_root = '/sys/fs/cgroup'
143 # If the slice is frozen, then we'll get an EBUSY when trying to write to the task
144 # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
145 # in this case to error out the shell. (an alternative would be to un-freeze it,
146 # add the task, and re-freeze it)
149 for subsystem in ['cpuset','memory','blkio','cpuacct','cpuacct,cpu','freezer']:
151 current_cgroup = subsystem
153 # There seems to be a bug in the cgroup schema: cpuacct,cpu can become cpu,cpuacct
154 # We need to handle both
157 subsystem_comps = subsystem.split(',')
158 subsystem_comps.reverse()
159 subsystem_alt = ','.join(subsystem_comps)
160 tasks_path_alt = [sysfs_root, subsystem_alt, subdirs[subsystem], 'tasks']
164 tasks_path = [sysfs_root,subsystem,subdirs[subsystem],'tasks']
165 tasks_path_str = '/'.join(tasks_path)
168 f = open(tasks_path_str, 'w')
170 tasks_path_alt_str = '/'.join(tasks_path_alt)
171 f = open(tasks_path_alt_str, 'w')
173 f.write(str(os.getpid()))
174 if (subsystem=='freezer'):
178 if (not subdirs.has_key(subsystem)):
182 print "Error assigning cgroup %s (pid=%s) for slice %s"%(current_cgroup,driver_pid, slice_name)
186 def chcontext (path):
187 retcod = setns.chcontext (path)
189 print 'WARNING - setns(%s)=>%s (ignored)'%(path,retcod)
192 # Use init_pid and not driver_pid to locate reference namespaces
193 ref_ns = "/proc/%s/ns/"%init_pid
195 if True: chcontext(ref_ns+'uts')
196 if True: chcontext(ref_ns+'ipc')
198 if (not args.no_pidns): chcontext(ref_ns+'pid')
199 if (not args.no_netns): chcontext(ref_ns+'net')
200 if (not args.no_mntns): chcontext(ref_ns+'mnt')
203 if (not os.access('/proc/self',0)):
207 for (sysctl_file, sysctl_name, sysctl_val) in sysctls:
208 for fn in ["/sbin/sysctl", "/usr/sbin/sysctl", "/bin/sysctl", "/usr/bin/sysctl"]:
209 if os.path.exists(fn):
210 os.system('%s -w %s=%s >/dev/null 2>&1'%(fn, sysctl_name,sysctl_val))
213 print "Error: image does not have a sysctl binary"
215 # cgroups is not yet LXC-safe, so we need to use the coarse grained access control
216 # strategy of unmounting the filesystem
219 for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event','systemd']:
220 fs_path = '/sys/fs/cgroup/%s'%subsystem
221 if (not umount(fs_path,'-l')):
222 print 'WARNING - umount failed (ignored) with path=',fs_path
224 # Leaving these comments for historical reference
225 #print "Error disabling cgroup access"
226 #exit(1) - Don't need this because failure here implies failure in the call to umount /sys/fs/cgroup
228 if (not umount('/sys/fs/cgroup')):
229 print "Error disabling cgroup access"
234 # capsh has a --user option starting with f14
235 # so if only for f12 we need to fake this one
237 # capsh.c does essentially the following when invoked with --user:
238 # pwd = getpwnam(user); ...
239 # ngroups = MAX_GROUPS;
240 # status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ...
241 # status = setgroups(ngroups, groups); ...
242 # status = setgid(pwd->pw_gid); ...
243 # status = setuid(pwd->pw_uid); ...
244 # however we cannot simulate that ourselves because if we did in this process then
245 # capsh could not be allowed to mess with caps any more
247 def getuid (slicename):
250 return pwd.getpwnam(slicename).pw_uid
255 cap_arg = '--drop='+drop_capabilities
258 if (args.nosliceuid):
259 # we still want to drop capabilities, but don't want to switch UIDs
260 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
262 uid = getuid (slice_name)
264 print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name
266 exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--login',]+args.command_to_run
267 # once we can drop f12, it would be nicer to instead go for
268 # exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--','--login',]+args.command_to_run
270 exec_args = [arch,'/usr/sbin/capsh','--','--login']+args.command_to_run
272 os.environ['SHELL'] = '/bin/sh'
273 if os.path.exists('/etc/planetlab/lib/bind_public.so'):
274 os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
275 if not args.noslicehome:
276 os.environ['HOME'] = '/home/%s'%slice_name
277 os.chdir("/home/%s"%(slice_name))
278 if debug: print 'lxcsu:execv:','/usr/bin/setarch',exec_args
279 os.execv('/usr/bin/setarch',exec_args)
282 _,status = os.waitpid(fork_pid,0)
283 exit(os.WEXITSTATUS(status))
285 if __name__ == '__main__':