Replaced lxcsu with slicesu. The latter supports hypervisors e.g. KVM
Sapan Bhatia [Wed, 19 Mar 2014 05:43:23 +0000 (01:43 -0400)]
slicesu [new file with mode: 0644]

diff --git a/slicesu b/slicesu
new file mode 100644 (file)
index 0000000..15e5854
--- /dev/null
+++ b/slicesu
@@ -0,0 +1,310 @@
+#!/usr/bin/python
+
+import sys
+import os
+import setns
+import pdb
+
+from argparse import ArgumentParser
+
+# can set to True here, but also use the -d option
+debug = False
+
+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 get_cgroup_subdirs_for_pid(pid):
+       cgroup_info_file = '/proc/%s/cgroup'%pid
+       cgroup_lines = open(cgroup_info_file).read().splitlines()
+       
+       subdirs = {}
+       for line in cgroup_lines:
+               try:
+                       _, cgroup_name, subdir = line.split(':')
+                       subdirs[cgroup_name] = subdir
+               except Exception, e:
+                       print "Error reading cgroup info: %s"%str(e)
+                       pass
+       
+       return subdirs
+               
+       
+def umount(fs_dir, opts=''):
+       output = os.popen('/bin/umount %s %s 2>&1'%(opts, fs_dir)).read()
+       return ('device is busy' not in output)
+
+def kvmsu(slice_name, args):
+       # Find MAC address of virt interface
+       ifstr = os.popen('/usr/bin/virsh domiflist %s'%slice_name).read().strip()
+       mac_address = ifstr.split()[-1]
+
+       # Find IP address of virt interface
+       ipaddr_str = os.popen('arp -an | grep %s'%'78:2b:cb:2d:f0:60').read().strip()
+       ip_addr_part = ipaddr_str.split()[1]
+       if (ip_addr_part[0]=='(' and ip_addr_part[-1]==')'):
+               ip_addr = ip_addr_part[1:len(ip_addr_part)-1]
+       
+       os.execv('/usr/bin/ssh',['/usr/bin/ssh','-o','StrictHostKeyChecking=no','root@%s'%ip_addr,'"$@"'])
+       
+
+def lxcsu(slice_name, args):
+       # plain lxcsu
+       if not args.internal:
+               # no command given: enter interactive shell
+               if not args.command_to_run: args.command_to_run=['/bin/sh']
+               args.command_to_run = [ '-c' ] + [" ".join(args.command_to_run)]
+
+       # support for either setting debug at the top of this file, or on the command-line
+       if args.debug:
+               global debug
+               debug=True
+
+       try:
+               cmd = '/usr/bin/virsh --connect lxc:/// domid %s'%slice_name
+               # convert to int as a minimal raincheck
+               driver_pid = int(os.popen(cmd).read().strip())
+               # locate the pid for the - expected - single child, that would be the init for that VM
+               #init_pid = int(open("/proc/%s/task/%s/children"%(driver_pid,driver_pid)).read().strip())
+               init_pid = int(os.popen('pgrep -P %s'%driver_pid).readlines()[0].strip())
+               # Thierry: I am changing the code below to use child_pid instead of driver_pid
+               # for the namespace handling features, that I was able to check
+               # I've left the other ones as they were, i.e. using driver_pid, but I suspect
+               # they chould be changed as well
+
+       except:
+               print "Domain %s not found"%slice_name
+               exit(1)
+
+       if not driver_pid or not init_pid:
+               print "Domain %s not started"%slice_name
+               exit(1)
+
+       if debug: print "Found driver_pid",driver_pid,'and init_pid=',init_pid
+       # xxx probably init_pid here too
+       arch = getarch('/proc/%s/exe'%driver_pid)
+
+       # Set sysctls specific to slice
+       sysctls = []
+       sysctl_dir = '/etc/planetlab/vsys-attributes/%s'%slice_name
+       if (os.access(sysctl_dir,0)):
+               entries = os.listdir(sysctl_dir)
+               for e in entries:
+                       prefix = 'vsys_sysctl.'
+                       if (e.startswith(prefix)):
+                               sysctl_file = '/'.join([sysctl_dir,e])
+                               sysctl_name = e[len(prefix):]
+                               sysctl_val = open(sysctl_file).read()
+                               sysctls.append((sysctl_file, sysctl_name, sysctl_val))
+
+       # xxx probably init_pid here too
+       subdirs = get_cgroup_subdirs_for_pid(driver_pid) 
+       sysfs_root = '/sys/fs/cgroup'
+
+       # 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)
+       # Enter cgroups
+       current_cgroup = ''
+       for subsystem in ['cpuset','memory','blkio','cpuacct','cpuacct,cpu','freezer']:
+               try:
+                       current_cgroup = subsystem
+
+                       # There seems to be a bug in the cgroup schema: cpuacct,cpu can become cpu,cpuacct
+                       # We need to handle both
+                       task_path_alt = None
+                       try:
+                          subsystem_comps = subsystem.split(',')
+                          subsystem_comps.reverse()
+                          subsystem_alt = ','.join(subsystem_comps)
+                          tasks_path_alt = [sysfs_root, subsystem_alt, subdirs[subsystem], 'tasks']
+                       except Exception,e:
+                               pass
+                          
+                       tasks_path = [sysfs_root,subsystem,subdirs[subsystem],'tasks']
+                       tasks_path_str = '/'.join(tasks_path)
+        
+                       try:
+                               f = open(tasks_path_str, 'w')
+                       except:
+                               tasks_path_alt_str = '/'.join(tasks_path_alt)
+                               f = open(tasks_path_alt_str, 'w')
+
+                       f.write(str(os.getpid()))
+                       if (subsystem=='freezer'):
+                               f.close()
+
+               except Exception,e:
+                       if (not subdirs.has_key(subsystem)):
+                               pass
+                       else:
+                               if debug: print e 
+                               print "Error assigning cgroup %s (pid=%s) for slice %s"%(current_cgroup,driver_pid, slice_name)
+                               exit(1)
+
+
+       def chcontext (path):
+               retcod = setns.chcontext (path)
+               if retcod != 0:
+                       print 'WARNING - setns(%s)=>%s (ignored)'%(path,retcod)
+               return retcod
+
+       # Use init_pid and not driver_pid to locate reference namespaces
+       ref_ns = "/proc/%s/ns/"%init_pid
+
+       if True:                                        chcontext(ref_ns+'uts')
+       if True:                                        chcontext(ref_ns+'ipc')
+               
+       if (not args.no_pidns):         chcontext(ref_ns+'pid')
+       if (not args.no_netns):         chcontext(ref_ns+'net')
+       if (not args.no_mntns):         chcontext(ref_ns+'mnt')
+
+       proc_mounted = False
+       if (not os.access('/proc/self',0)):
+               proc_mounted = True
+               setns.proc_mount()
+
+       for (sysctl_file, sysctl_name, sysctl_val) in sysctls:
+               for fn in ["/sbin/sysctl", "/usr/sbin/sysctl", "/bin/sysctl", "/usr/bin/sysctl"]:
+                       if os.path.exists(fn):
+                               os.system('%s -w %s=%s  >/dev/null 2>&1'%(fn, sysctl_name,sysctl_val))
+                               break
+                       else:
+                               print "Error: image does not have a sysctl binary"
+
+       # cgroups is not yet LXC-safe, so we need to use the coarse 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','systemd']:
+               fs_path = '/sys/fs/cgroup/%s'%subsystem
+               if (not umount(fs_path,'-l')):
+                       print 'WARNING - umount failed (ignored) with path=',fs_path
+                       pass
+                       # Leaving these comments for historical reference
+                       #print "Error disabling cgroup access"
+                       #exit(1) - Don't need this because failure here implies failure in the call to umount /sys/fs/cgroup
+
+       if (not umount('/sys/fs/cgroup')):
+               print "Error disabling cgroup access"
+               exit(1)
+
+       fork_pid = os.fork()
+
+       def getuid (slicename):
+               import pwd
+               try:
+                       return pwd.getpwnam(slicename).pw_uid
+               except:
+                       return
+
+       if (fork_pid == 0):
+               if (not args.root):
+                       setns.drop_caps() 
+                       if (args.nosliceuid):
+                               # we still want to drop capabilities, but don't want to switch UIDs
+                               exec_args = [arch,'/bin/sh','--login',]+args.command_to_run
+                       else:
+                                                               # let's keep this check even though we don't use the uid
+                                                               # as a way of checking the existence of the slice account
+                               uid = getuid (slice_name)
+                               if not uid:
+                                       print "lxcsu could not spot %s in /etc/passwd - exiting"%slice_name
+                                       exit(1)
+                               exec_args = [arch,'/usr/bin/sudo','-u',slice_name,'/bin/sh','--login',]+args.command_to_run
+# once we can drop f12, it would be nicer to instead go for
+# exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--login',]+args.command_to_run
+               else:
+                       exec_args = [arch,'/bin/sh','--login']+args.command_to_run
+
+               os.environ['SHELL'] = '/bin/sh'
+               if os.path.exists('/etc/planetlab/lib/bind_public.so'):
+                       os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
+               if not args.noslicehome:
+                       os.environ['HOME'] = '/home/%s'%slice_name
+                       os.chdir("/home/%s"%(slice_name))
+               if debug: print 'lxcsu:execv:','/usr/bin/setarch',exec_args
+               os.execv('/usr/bin/setarch',exec_args)
+       else:
+               setns.proc_umount()
+               _,status = os.waitpid(fork_pid,0)
+               exit(os.WEXITSTATUS(status))
+
+def main ():
+       parser = ArgumentParser()
+       parser.add_argument("-n", "--nonet",
+                                                                               action="store_true", dest="no_netns", default=False,
+                                                                               help="Don't enter network namespace")
+       parser.add_argument("-m", "--nomnt",
+                                                                               action="store_true", dest="no_mntns", default=False,
+                                                                               help="Don't enter mount namespace")
+       parser.add_argument("-p", "--nopid",
+                                                                               action="store_true", dest="no_pidns", default=False,
+                                                                               help="Don't enter pid namespace")
+       parser.add_argument("-r", "--root",
+                                                                               action="store_true", dest="root", default=False,
+                                                                               help="Enter as root: be careful")
+       parser.add_argument("-i","--internal",
+                                                                               action="store_true", dest="internal", default=False,
+                                                                               help="does *not* prepend '-- -c' to arguments - or invoke lxcsu-internal")
+       parser.add_argument("-d","--debug",
+                                                                               action='store_true', dest='debug', default=False,
+                                                                               help="debug option")
+       parser.add_argument("-s","--nosliceuid",
+                                                                               action='store_true', dest="nosliceuid", default=False,
+                                                                               help="do not change to slice uid inside of slice")
+       parser.add_argument("-o","--noslicehome",
+                                                                               action='store_true', dest="noslicehome", default=False,
+                                                                               help="do not change to slice home directory inside of slice")
+
+       if os.path.exists("/etc/lxcsu_default"):
+               defaults = parser.parse_args(file("/etc/lxcsu_default","r").read().split())
+               parser.set_defaults(**defaults.__dict__)
+
+       parser.add_argument ("slice_name")
+       parser.add_argument ("command_to_run",nargs="*")
+
+       args = parser.parse_args()
+       slice_name=args.slice_name
+
+       # unless we run the symlink 'lxcsu-internal', or we specify the -i option, prepend '--' '-c'
+       if sys.argv[0].find('internal')>=0: args.internal=True
+
+       if len(args.command_to_run)>0 and (args.command_to_run[0] == "/sbin/service"):
+               # A quick hack to support nodemanager interfaces.py when restarting
+               # networking in a slice.
+               args.nosliceuid = True
+
+       try:
+               cmd = '/usr/bin/virsh dominfo %s'%slice_name
+               info = os.popen(cmd).read()
+               d = {}
+
+               ostype = None
+               for line in info.split('\n'):
+                       pair = line.split(':')
+                       d[pair[0].strip()] = pair[1].strip()
+                       if (pair[0].strip()=='OS Type'):
+                               ostype = pair[1].strip()
+                               break
+       except:
+               print "Domain %s not found"%slice_name
+
+       is_kvm = ostype=='hvm'
+
+       if (is_kvm):
+               kvmsu(slice_name, args)
+       else:
+               lxcsu(slice_name, args)
+
+if __name__ == '__main__':
+               main()