import os
import sys
-#from optparse import OptionParser
+from optparse import OptionParser
-drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'.split(',')
+drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
+
+def getarch(f):
+ output = os.popen('readelf -h %s 2>&1'%f).readlines()
+ classlines = [x for x in output if ('Class' in x.split(':')[0])]
+ line = classlines[0]
+ c = line.split(':')[1]
+ if ('ELF64' in c):
+ return 'x86_64'
+ elif ('ELF32' in c):
+ return 'i686'
+ else:
+ raise Exception('Could not determine architecture')
+
+def umount(fs_dir):
+ output = os.popen('/bin/umount %s 2>&1'%fs_dir).read()
+ return ('device is busy' not in fs_dir)
-"""
parser = OptionParser()
-parser.add_option("-n", "--net",
+parser.add_option("-n", "--nonet",
action="store_true", dest="netns", default=False,
- help="Enter network namespace")
-parser.add_option("-m", "--mnt",
+ help="Don't enter network namespace")
+parser.add_option("-m", "--nomnt",
action="store_true", dest="mntns", default=False,
- help="Enter mount namespace")
-parser.add_option("-p", "--pid",
+ help="Don't enter mount namespace")
+parser.add_option("-p", "--nopid",
action="store_true", dest="pidns", default=False,
- help="Enter pid namespace")
+ help="Don't enter pid namespace")
+parser.add_option("-r", "--root",
+ action="store_true", dest="root", default=False,
+ help="Enter as root: be careful")
(options, args) = parser.parse_args()
-"""
-args = sys.argv[1:]
try:
- slice_name = args[0]
+ slice_name = args[0]
except IndexError:
- print "You must specify a vm name"
- exit(1)
+ print "You must specify a vm name"
+ exit(1)
try:
- cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
- output = os.popen(cmd).readlines()
+ cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
+ output = os.popen(cmd).readlines()
except:
- print "Error finding slice %s"%slice_name
- exit(1)
+ print "Error finding slice %s"%slice_name
+ exit(1)
slice_spec = None
+
+# xxx fixme xxx - provide a default as this is not always properly computed
+arch = 'x86_64'
+
for e in output:
- try:
- l = e.rstrip()
- path = l.split(':')[0]
- comp = l.rsplit(':')[-1]
- slice_name_check = comp.rsplit('/')[-1]
-
- if (slice_name_check == slice_name):
- slice_path = path
- pid = slice_path.split('/')[2]
- cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00')
- if (cmdline == '/sbin/init'):
- slice_spec = slice_path
- break
- except:
- break
+ try:
+ l = e.rstrip()
+ path = l.split(':')[0]
+ comp = l.rsplit(':')[-1]
+ slice_name_check = comp.rsplit('/')[-1]
+
+ if (slice_name_check == slice_name):
+ slice_path = path
+ pid = slice_path.split('/')[2]
+ cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00')
+ if (cmdline == '/sbin/init'):
+ slice_spec = slice_path
+ arch = getarch('/proc/%s/exe'%pid)
+ break
+ except:
+ break
if (not slice_spec or not pid):
print "Not started: %s"%slice_name
exit(1)
-r1 = setns.chcontext('/proc/%s/ns/utc'%pid)
-r2 = setns.chcontext('/proc/%s/ns/ipc'%pid)
-path = '/proc/%s/ns/net'%pid
-r3 = setns.chcontext(path)
+# Enter cgroups
+try:
+ for subsystem in ['cpuset','memory','blkio']:
+ open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid()))
+
+except:
+ print "Error assigning resources: %s"%slice_name
+ exit(1)
+
+try:
+ open('/sys/fs/cgroup/cpuacct/system/libvirtd.service/libvirt/lxc/%s/tasks'%slice_name,'w').write(str(os.getpid()))
+except:
+ print "Error assigning cpuacct: %s" % slice_name
+ exit(1)
+
+# If the slice is frozen, then we'll get an EBUSY when trying to write to the task
+# list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
+# in this case to error out the shell. (an alternative would be to un-freeze it,
+# add the task, and re-freeze it)
+try:
+ f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w')
+ f.write(str(os.getpid()))
+ # note: we need to call f.close() explicitly, or we'll get an exception in
+ # the object destructor, which will not be caught
+ f.close()
+except:
+ print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name
+ exit(1)
+
+setns.chcontext('/proc/%s/ns/uts'%pid)
+setns.chcontext('/proc/%s/ns/ipc'%pid)
+
+if (not options.netns):
+ setns.chcontext('/proc/%s/ns/net'%pid)
-open('/proc/lxcsu','w').write(pid)
-open('/proc/pidsu','w').write(pid)
+if (not options.mntns):
+ open('/proc/lxcsu','w').write(pid)
+
+if (not options.pidns):
+ open('/proc/pidsu','w').write(pid)
+
+# cgroups is not yet LXC-safe, so we need to use the course grained access control
+# strategy of unmounting the filesystem
+
+umount_result = True
+for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event']:
+ fs_path = '/sys/fs/cgroup/%s'%subsystem
+ if (not umount(fs_path)):
+ print "Error disabling cgroup access"
+ exit(1)
+
+if (not umount('/sys/fs/cgroup')):
+ print "Error disabling cgroup access"
+ exit(1)
pid = os.fork()
-cap_args = map(lambda c:'--drop='+c, drop_capabilities)
-
if (pid == 0):
- os.execv('/usr/sbin/capsh',cap_args+['--']+args[1:])
+ cap_arg = '--drop='+drop_capabilities
+
+ if (not options.root):
+ exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+args[1:]
+ else:
+ exec_args = [arch,'/usr/sbin/capsh','--','--login']+args[1:]
+
+ os.environ['SHELL'] = '/bin/sh'
+ os.execv('/usr/bin/setarch',exec_args)
else:
- os.waitpid(pid,0)
+ _,status = os.waitpid(pid,0)
+ exit(os.WEXITSTATUS(status))
git://git.onelab.eu / lxc-userspace.git / blobdiff