Setting tag lxc-userspace-1.0-11
[lxc-userspace.git] / lxcsu
diff --git a/lxcsu b/lxcsu
index 26c1e9d..b05342a 100755 (executable)
--- a/lxcsu
+++ b/lxcsu
@@ -3,11 +3,10 @@
 import sys
 import os
 import setns
+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
 
@@ -23,38 +22,81 @@ def getarch(f):
     else:
         raise Exception('Could not determine architecture')
 
-def umount(fs_dir):
-    output = os.popen('/bin/umount %s 2>&1'%fs_dir).read()
+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 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="no_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="no_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="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")
+                                       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")
-    parser.add_argument("-s","--nosliceuid", dest="nosliceuid", default=False,
-                        help="do not change to slice uid inside of slice")
+                                       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
 
+    # 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
 
@@ -65,191 +107,170 @@ def main ():
 
     # 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
+       # 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)]
 
     try:
-        cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
-        output = os.popen(cmd).readlines()
-    except:
-        print "Error finding slice %s"%slice_name
-        exit(1)
-
-    slice_spec = None
-
-    # provide a default as this is not always properly computed
-    arch = None
+        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
 
-    for e in output:
-        try:
-            l = e.rstrip()
-            path = l.split(':')[0]  
-            comp = l.rsplit(':')[-1]
-            slice_name_check = comp.rsplit('/')[-1]
-            if debug: print "dealing with >%s<"%slice_name_check
-            
-            if (slice_name_check == slice_name):
-                if debug: print "found %s"%slice_name
-                slice_path = path
-                pid = slice_path.split('/')[2]
-                cmdline = open('/proc/%s/cmdline'%pid).read().rstrip('\n\x00')
-                if (cmdline == '/sbin/init') or (cmdline.startswith("init [")):
-                    slice_spec = slice_path
-                    arch = getarch('/proc/%s/exe'%pid)
-                    break
-        except Exception,e:
-            if debug: 
-                import traceback
-                print "BEG lxcsu - ignoring exception"
-                traceback.print_exc()
-                print "END lxcsu - ignoring exception"
-            pass
+    except:
+        print "Domain %s not found"%slice_name
+       exit(1)
 
-    if (not slice_spec or not pid):
-        print "Not started: %s"%slice_name
-        exit(1)
+    if not driver_pid or not init_pid:
+        print "Domain %s not started"%slice_name
+       exit(1)
 
-    if arch is None:
-        arch = 'x86_64'
+    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:
+       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:
-        print "Error assigning resources: %s"%slice_name
-        exit(1)
+           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))
 
-    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)
+    # 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)
-    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)
+    # 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()
 
-    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)
+        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
 
-    if (not args.netns):
-        setns.chcontext('/proc/%s/ns/net'%pid)
+    # Use init_pid and not driver_pid to locate reference namespaces
+    ref_ns = "/proc/%s/ns/"%init_pid
 
-    if (not args.mntns):
-        setns.chcontext('/proc/%s/ns/mnt'%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()
+       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'%(fn, sysctl_name,sysctl_val))
-                        break
-                else:
-                    print "Error: image does not have a sysctl binary"
+       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']:
-        fs_path = '/sys/fs/cgroup/%s'%subsystem
-        if (not umount(fs_path)):
-            print "Error disabling cgroup access"
-            exit(1)
+    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)
 
-    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
+    fork_pid = os.fork()
 
+    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,'/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'
-        os.environ['HOME'] = '/home/%s'%slice_name
         if os.path.exists('/etc/planetlab/lib/bind_public.so'):
             os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
-        os.chdir("/home/%s"%(slice_name))
+        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)
+        _,status = os.waitpid(fork_pid,0)
         exit(os.WEXITSTATUS(status))
 
 if __name__ == '__main__':
-    main()
+       main()