Fixes to kvmsu function

[lxc-userspace.git] / lxcsu

diff --git a/lxcsu b/lxcsu
index ebc3cf5..b05342a 100755 (executable)
--- a/lxcsu
+++ b/lxcsu
@@ -3,12 +3,10 @@
 import sys
 import os
 import setns
-import pdb
+import pwd
 
 from argparse import ArgumentParser
 
-drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
-
 # can set to True here, but also use the -d option
 debug = False
 
@@ -81,6 +79,24 @@ def main ():
     args = parser.parse_args()
     slice_name=args.slice_name
 
+    # support for either setting debug at the top of this file, or on the command-line
+    if args.debug:
+        global debug
+       debug=True
+
+    # somehow some older nodes won't be able to find the login name in /etc/passwd 
+    # when this is done down the road, so compute slice_uid while in a safe env
+    # even though we don't use the slice_uid any more, this is still 
+    # checked later on as a means to ensure existence of the slice account
+    try:
+        slice_uid = pwd.getpwnam(slice_name).pw_uid
+    except Exception, e:
+        if debug:
+            import traceback
+            print 'error while computing slice_uid',e
+            traceback.print_exc()
+        slice_uid=None
+
     # 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
 
@@ -95,17 +111,13 @@ def main ():
        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(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
@@ -231,43 +243,21 @@ def main ():
 
     fork_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 (fork_pid == 0):
-        cap_arg = '--drop='+drop_capabilities
-
         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,'/usr/sbin/capsh',cap_arg,'--','--login',]+args.command_to_run
+                exec_args = [arch,'/bin/sh','--login',]+args.command_to_run
             else:
-                uid = getuid (slice_name)
-                if not uid:
+                if not slice_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
+                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
+# 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
+            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'):