8 from argparse import ArgumentParser
10 # can set to True here, but also use the -d option
14 exe_filename='/proc/%s/exe'%pid
15 output = os.popen('readelf -h %s 2>&1'%exe_filename).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 for pid %s'%pid)
26 def get_cgroup_subdirs_for_pid(pid):
27 cgroup_info_file = '/proc/%s/cgroup'%pid
28 cgroup_lines = open(cgroup_info_file).read().splitlines()
31 for line in cgroup_lines:
33 _, cgroup_name, subdir = line.split(':')
34 subdirs[cgroup_name] = subdir
36 print "Error reading cgroup info: %s"%str(e)
42 def umount(fs_dir, opts=''):
43 output = os.popen('/bin/umount %s %s 2>&1'%(opts, fs_dir)).read()
44 return ('device is busy' not in output)
47 parser = ArgumentParser()
48 parser.add_argument("-n", "--nonet",
49 action="store_true", dest="no_netns", default=False,
50 help="Don't enter network namespace")
51 parser.add_argument("-m", "--nomnt",
52 action="store_true", dest="no_mntns", default=False,
53 help="Don't enter mount namespace")
54 parser.add_argument("-p", "--nopid",
55 action="store_true", dest="no_pidns", default=False,
56 help="Don't enter pid namespace")
57 parser.add_argument("-r", "--root",
58 action="store_true", dest="root", default=False,
59 help="Enter as root: be careful")
60 parser.add_argument("-i","--internal",
61 action="store_true", dest="internal", default=False,
62 help="does *not* prepend '-- -c' to arguments - or invoke lxcsu-internal")
63 parser.add_argument("-d","--debug",
64 action='store_true', dest='debug', default=False,
66 parser.add_argument("-s","--nosliceuid",
67 action='store_true', dest="nosliceuid", default=False,
68 help="do not change to slice uid inside of slice")
69 parser.add_argument("-o","--noslicehome",
70 action='store_true', dest="noslicehome", default=False,
71 help="do not change to slice home directory inside of slice")
73 if os.path.exists("/etc/lxcsu_default"):
74 defaults = parser.parse_args(file("/etc/lxcsu_default","r").read().split())
75 parser.set_defaults(**defaults.__dict__)
77 parser.add_argument ("slice_name")
78 parser.add_argument ("command_to_run",nargs="*")
80 args = parser.parse_args()
81 slice_name=args.slice_name
83 # support for either setting debug at the top of this file, or on the command-line
88 # somehow some older nodes won't be able to find the login name in /etc/passwd
89 # when this is done down the road, so compute slice_uid while in a safe env
90 # even though we don't use the slice_uid any more, this is still
91 # checked later on as a means to ensure existence of the slice account
93 slice_uid = pwd.getpwnam(slice_name).pw_uid
97 print 'error while computing slice_uid',e
101 # unless we run the symlink 'lxcsu-internal', or we specify the -i option, prepend '--' '-c'
102 if sys.argv[0].find('internal')>=0: args.internal=True
104 if len(args.command_to_run)>0 and (args.command_to_run[0] == "/sbin/service"):
105 # A quick hack to support nodemanager interfaces.py when restarting
106 # networking in a slice.
107 args.nosliceuid = True
110 if not args.internal:
111 # no command given: enter interactive shell
112 if not args.command_to_run: args.command_to_run=['/bin/sh']
113 args.command_to_run = [ '-c' ] + [" ".join(args.command_to_run)]
116 cmd = '/usr/bin/virsh --connect lxc:/// domid %s'%slice_name
117 # convert to int as a minimal raincheck
118 driver_pid = int(os.popen(cmd).read().strip())
119 # locate the pid for the - expected - single child, that would be the init for that VM
120 #init_pid = int(open("/proc/%s/task/%s/children"%(driver_pid,driver_pid)).read().strip())
121 init_pid = int(os.popen('pgrep -P %s'%driver_pid).readlines()[0].strip())
122 # Thierry: I am changing the code below to use init_pid instead of driver_pid
123 # for the namespace handling features, that I was able to check
124 # I've left the other ones as they were, i.e. using driver_pid, but I suspect
125 # some should be changed as well
128 print "Domain %s not found"%slice_name
131 if not driver_pid or not init_pid:
132 print "Domain %s not started"%slice_name
135 if debug: print "Found driver_pid",driver_pid,'and init_pid=',init_pid
136 # driver_pid is always x86_64, we need to look at the VM's init process here
137 arch = getarch(init_pid)
139 # Set sysctls specific to slice
141 sysctl_dir = '/etc/planetlab/vsys-attributes/%s'%slice_name
142 if (os.access(sysctl_dir,0)):
143 entries = os.listdir(sysctl_dir)
145 prefix = 'vsys_sysctl.'
146 if (e.startswith(prefix)):
147 sysctl_file = '/'.join([sysctl_dir,e])
148 sysctl_name = e[len(prefix):]
149 sysctl_val = open(sysctl_file).read()
150 sysctls.append((sysctl_file, sysctl_name, sysctl_val))
152 # xxx probably init_pid here too
153 subdirs = get_cgroup_subdirs_for_pid(driver_pid)
154 sysfs_root = '/sys/fs/cgroup'
156 # If the slice is frozen, then we'll get an EBUSY when trying to write to the task
157 # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
158 # in this case to error out the shell. (an alternative would be to un-freeze it,
159 # add the task, and re-freeze it)
162 for subsystem in ['cpuset','memory','blkio','cpuacct','cpuacct,cpu','freezer']:
164 current_cgroup = subsystem
166 # There seems to be a bug in the cgroup schema: cpuacct,cpu can become cpu,cpuacct
167 # We need to handle both
170 subsystem_comps = subsystem.split(',')
171 subsystem_comps.reverse()
172 subsystem_alt = ','.join(subsystem_comps)
173 tasks_path_alt = [sysfs_root, subsystem_alt, subdirs[subsystem], 'tasks']
177 tasks_path = [sysfs_root,subsystem,subdirs[subsystem],'tasks']
178 tasks_path_str = '/'.join(tasks_path)
181 f = open(tasks_path_str, 'w')
183 tasks_path_alt_str = '/'.join(tasks_path_alt)
184 f = open(tasks_path_alt_str, 'w')
186 f.write(str(os.getpid()))
187 if (subsystem=='freezer'):
191 if (not subdirs.has_key(subsystem)):
195 print "Error assigning cgroup %s (pid=%s) for slice %s"%(current_cgroup,driver_pid, slice_name)
199 def chcontext (path):
200 retcod = setns.chcontext (path)
202 print 'WARNING - setns(%s)=>%s (ignored)'%(path,retcod)
205 # Use init_pid and not driver_pid to locate reference namespaces
206 ref_ns = "/proc/%s/ns/"%init_pid
208 if True: chcontext(ref_ns+'uts')
209 if True: chcontext(ref_ns+'ipc')
211 if (not args.no_pidns): chcontext(ref_ns+'pid')
212 if (not args.no_netns): chcontext(ref_ns+'net')
213 if (not args.no_mntns): chcontext(ref_ns+'mnt')
216 if (not os.access('/proc/self',0)):
220 for (sysctl_file, sysctl_name, sysctl_val) in sysctls:
221 for fn in ["/sbin/sysctl", "/usr/sbin/sysctl", "/bin/sysctl", "/usr/bin/sysctl"]:
222 if os.path.exists(fn):
223 os.system('%s -w %s=%s >/dev/null 2>&1'%(fn, sysctl_name,sysctl_val))
226 print "Error: image does not have a sysctl binary"
228 # cgroups is not yet LXC-safe, so we need to use the coarse grained access control
229 # strategy of unmounting the filesystem
232 for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event','systemd']:
233 fs_path = '/sys/fs/cgroup/%s'%subsystem
234 if (not umount(fs_path,'-l')):
235 print 'WARNING - umount failed (ignored) with path=',fs_path
237 # Leaving these comments for historical reference
238 #print "Error disabling cgroup access"
239 #exit(1) - Don't need this because failure here implies failure in the call to umount /sys/fs/cgroup
241 if (not umount('/sys/fs/cgroup')):
242 print "Error disabling cgroup access"
250 if (args.nosliceuid):
251 # we still want to drop capabilities, but don't want to switch UIDs
252 exec_args = [arch,'/bin/sh','--login',]+args.command_to_run
255 print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name
257 exec_args = [arch,'/usr/bin/sudo','-u',slice_name,'/bin/sh','--login',]+args.command_to_run
258 # once we can drop f12, it would be nicer to instead go for
259 # exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--login',]+args.command_to_run
261 exec_args = [arch,'/bin/sh','--login']+args.command_to_run
263 os.environ['SHELL'] = '/bin/sh'
264 if os.path.exists('/etc/planetlab/lib/bind_public.so'):
265 os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
266 if not args.noslicehome:
267 os.environ['HOME'] = '/home/%s'%slice_name
268 os.chdir("/home/%s"%(slice_name))
269 if debug: print 'lxcsu:execv:','/usr/bin/setarch',exec_args
270 os.execv('/usr/bin/setarch',exec_args)
273 _,status = os.waitpid(fork_pid,0)
274 exit(os.WEXITSTATUS(status))
276 if __name__ == '__main__':