redid indent=4 but more carefully this time
[lxc-userspace.git] / lxcsu
diff --git a/lxcsu b/lxcsu
index 2de1265..3c63f74 100755 (executable)
--- a/lxcsu
+++ b/lxcsu
@@ -30,212 +30,216 @@ def umount(fs_dir, opts=''):
 def main ():
     parser = ArgumentParser()
     parser.add_argument("-n", "--nonet",
-                                        action="store_true", dest="netns", default=False,
-                                        help="Don't enter network namespace")
+                                       action="store_true", dest="netns", default=False,
+                                       help="Don't enter network namespace")
     parser.add_argument("-m", "--nomnt",
-                                        action="store_true", dest="mntns", default=False,
-                                        help="Don't enter mount namespace")
+                                       action="store_true", dest="mntns", default=False,
+                                       help="Don't enter mount namespace")
     parser.add_argument("-p", "--nopid",
-                                        action="store_true", dest="pidns", default=False,
-                                        help="Don't enter pid namespace")
+                                       action="store_true", dest="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")
+                                       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")
+                                       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")
+                                       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")
+                                       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")
+                                       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
-
-        # 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 domid %s'%slice_name
-            pidnum = int(os.popen(cmd).read().rstrip())
-        except:
-            print "Error finding slice %s"%slice_name
-            exit(1)
-
-        pid = '%s'%pidnum
-        cmdline = open('/proc/%s/cmdline'%pidnum).read().rstrip('\n\x00')
-        arch = getarch('/proc/%s/exe'%pid)
-
-        if (not pid):
-            print "lxcsu: domain not started: %s"%slice_name
-            exit(1)
-
-        if arch is None:
-            arch = 'x86_64'
-
-        # 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))
-
-        # Enter cgroups
+    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
+
+    # 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
+       pidnum = int(os.popen(cmd).read().rstrip())
+    except:
+        print "Error finding slice %s"%slice_name
+       exit(1)
+
+    pid = '%s'%pidnum
+    if debug: print "Found pidnum",pidnum
+    cmdline = open('/proc/%s/cmdline'%pidnum).read().rstrip('\n\x00')
+    arch = getarch('/proc/%s/exe'%pid)
+
+    if (not pid):
+        print "Not started: %s"%slice_name
+       exit(1)
+
+    if arch is None:
+       arch = 'x86_64'
+
+    # 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))
+
+    # 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 Exception,e:
+       if debug: print e 
+       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 Exception,e:
+       if debug: print e 
+       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 Exception,e:
+       if debug: print e 
+       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 args.pidns):
+       setns.chcontext('/proc/%s/ns/pid'%pid)
+
+    if (not args.netns):
+       setns.chcontext('/proc/%s/ns/net'%pid)
+
+    if (not args.mntns):
+       setns.chcontext('/proc/%s/ns/mnt'%pid)
+
+    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')):
+           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)
+
+    pid = os.fork()
+
+    # capsh has a --user option starting with f14
+    # so if only for f12 we need to fake this one
+    #
+    # capsh.c does essentially the following when invoked with --user:
+    #          pwd = getpwnam(user); ...
+    #          ngroups = MAX_GROUPS; 
+    #          status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ...
+    #          status = setgroups(ngroups, groups); ...
+    #          status = setgid(pwd->pw_gid); ...
+    #          status = setuid(pwd->pw_uid); ...
+    # however we cannot simulate that ourselves because if we did in this process then
+    # capsh could not be allowed to mess with caps any more
+
+    def getuid (slicename):
+        import pwd
         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()))
+            return pwd.getpwnam(slicename).pw_uid
         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 args.pidns):
-            setns.chcontext('/proc/%s/ns/pid'%pid)
-
-        if (not args.netns):
-            setns.chcontext('/proc/%s/ns/net'%pid)
-
-        if (not args.mntns):
-            setns.chcontext('/proc/%s/ns/mnt'%pid)
-
-        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')):
-                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)
-
-        pid = os.fork()
-
-        # capsh has a --user option starting with f14
-        # so if only for f12 we need to fake this one
-        #
-        # capsh.c does essentially the following when invoked with --user:
-        #               pwd = getpwnam(user); ...
-        #               ngroups = MAX_GROUPS; 
-        #               status = getgrouplist(user, pwd->pw_gid, groups, &ngroups); ...
-        #               status = setgroups(ngroups, groups); ...
-        #               status = setgid(pwd->pw_gid); ...
-        #               status = setuid(pwd->pw_uid); ...
-        # however we cannot simulate that ourselves because if we did in this process then
-        # capsh could not be allowed to mess with caps any more
-
-        def getuid (slicename):
-            import pwd
-            try:
-                return pwd.getpwnam(slicename).pw_uid
-            except:
-                return
-
-        if (pid == 0):
-            cap_arg = '--drop='+drop_capabilities
-
-            if (not args.root):
-                if (args.nosliceuid):
-                    # we still want to drop capabilities, but don't want to switch UIDs
-                    exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
-                else:
-                    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/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--login',]+args.command_to_run
+            return
+
+    if (pid == 0):
+        cap_arg = '--drop='+drop_capabilities
+
+        if (not args.root):
+            if (args.nosliceuid):
+                # we still want to drop capabilities, but don't want to switch UIDs
+                exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
+            else:
+                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/sbin/capsh',cap_arg,'--uid=%s'%uid,'--','--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,'/usr/sbin/capsh','--','--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)
+# exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--user=%s'%slice_name,'--','--login',]+args.command_to_run
         else:
-            setns.proc_umount()
-            _,status = os.waitpid(pid,0)
-            exit(os.WEXITSTATUS(status))
+            exec_args = [arch,'/usr/sbin/capsh','--','--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(pid,0)
+        exit(os.WEXITSTATUS(status))
 
 if __name__ == '__main__':
-    main()
+       main()