lxcsu

   1 #!/usr/bin/python
   2
   3
   4 import setns
   5 import os
   6 import sys
   7
   8 #from optparse import OptionParser
   9
  10 drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
  11
  12 def umount(fs_dir):
  13     output = os.popen('/bin/umount %s 2>&1'%fs_dir).read()
  14     return ('device is busy' not in fs_dir)
  15
  16
  17 """
  18 parser = OptionParser()
  19 parser.add_option("-n", "--net",
  20                   action="store_true", dest="netns", default=False,
  21                   help="Enter network namespace")
  22 parser.add_option("-m", "--mnt",
  23                   action="store_true", dest="mntns", default=False,
  24                   help="Enter mount namespace")
  25 parser.add_option("-p", "--pid",
  26                   action="store_true", dest="pidns", default=False,
  27                   help="Enter pid namespace")
  28
  29 (options, args) = parser.parse_args()
  30 """
  31 args = sys.argv[1:]
  32
  33 try:
  34         slice_name = args[0]
  35 except IndexError:
  36         print "You must specify a vm name"
  37         exit(1)
  38
  39 try:
  40         cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
  41         output = os.popen(cmd).readlines()
  42 except:
  43         print "Error finding slice %s"%slice_name
  44         exit(1)
  45
  46 slice_spec = None
  47 for e in output:
  48         try:
  49                 l = e.rstrip()
  50                 path = l.split(':')[0]
  51                 comp = l.rsplit(':')[-1]
  52                 slice_name_check = comp.rsplit('/')[-1]
  53
  54                 if (slice_name_check == slice_name):
  55                         slice_path = path
  56                         pid = slice_path.split('/')[2]
  57                         cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00')
  58                         if (cmdline == '/sbin/init'):
  59                                 slice_spec = slice_path
  60                                 break
  61         except:
  62                 break
  63
  64 if (not slice_spec or not pid):
  65     print "Not started: %s"%slice_name
  66     exit(1)
  67
  68 # Enter cgroups
  69 try:
  70     for subsystem in ['cpuset','memory','blkio']:
  71         open('/sys/fs/cgroup/%s/libvirt/lxc/%s/tasks'%(subsystem,slice_name),'w').write(str(os.getpid()))
  72
  73 except:
  74     print "Error assigning resources: %s"%slice_name
  75     exit(1)
  76
  77 try:
  78     open('/sys/fs/cgroup/cpuacct/system/libvirtd.service/libvirt/lxc/%s/tasks'%slice_name,'w').write(str(os.getpid()))
  79 except:
  80     print "Error assigning cpuacct: %s" % slice_name
  81     exit(1)
  82
  83 # If the slice is frozen, then we'll get an EBUSY when trying to write to the task
  84 # list for the freezer cgroup. Since the user couldn't do anything anyway, it's best
  85 # in this case to error out the shell. (an alternative would be to un-freeze it,
  86 # add the task, and re-freeze it)
  87 try:
  88     f=open('/sys/fs/cgroup/freezer/libvirt/lxc/%s/tasks'%(slice_name),'w')
  89     f.write(str(os.getpid()))
  90     # note: we need to call f.close() explicitly, or we'll get an exception in
  91     # the object destructor, which will not be caught
  92     f.close()
  93 except:
  94     print "Error adding task to freezer cgroup. Slice is probably frozen: %s" % slice_name
  95     exit(1)
  96
  97 r1 = setns.chcontext('/proc/%s/ns/uts'%pid)
  98 r2 = setns.chcontext('/proc/%s/ns/ipc'%pid)
  99 r3 = setns.chcontext('/proc/%s/ns/net'%pid)
 100
 101 open('/proc/lxcsu','w').write(pid)
 102 open('/proc/pidsu','w').write(pid)
 103
 104 # cgroups is not yet LXC-safe, so we need to use the course grained access control
 105 # strategy of unmounting the filesystem
 106
 107 umount_result = True
 108 for subsystem in ['cpuset','cpu,cpuacct','memory','devices','freezer','net_cls','blkio','perf_event']:
 109     fs_path = '/sys/fs/cgroup/%s'%subsystem
 110     if (not umount(fs_path)):
 111         print "Error disabling cgroup access"
 112         exit(1)
 113
 114 if (not umount('/sys/fs/cgroup')):
 115     print "Error disabling cgroup access"
 116     exit(1)
 117
 118 pid = os.fork()
 119
 120 if (pid == 0):
 121     cap_arg = '--drop='+drop_capabilities
 122     exec_args = ['/usr/sbin/capsh',cap_arg,'--','--login']+args[1:]
 123
 124     os.environ['SHELL'] = '/bin/sh'
 125     os.execv('/usr/sbin/capsh',exec_args)
 126 else:
 127     _,status = os.waitpid(pid,0)
 128     exit(os.WEXITSTATUS(status))