indent=4
Thierry Parmentelat [Thu, 9 Jan 2014 16:01:10 +0000 (17:01 +0100)]
lxcsu

diff --git a/lxcsu b/lxcsu
index 090cea1..0fa6c54 100755 (executable)
--- a/lxcsu
+++ b/lxcsu
@@ -12,256 +12,256 @@ drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
 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')
+    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 umount(fs_dir, opts=''):
-       output = os.popen('/bin/umount %s %s 2>&1'%(opts, fs_dir)).read()
-       return ('device is busy' not in output)
+    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")
-       parser.add_argument("-m", "--nomnt",
-                                               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")
-       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
-
-       # 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 = '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
-
-       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
-
-       if (not slice_spec or 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:
-               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:
-               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
+    parser = ArgumentParser()
+    parser.add_argument("-n", "--nonet",
+                                        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")
+    parser.add_argument("-p", "--nopid",
+                                        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")
+    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
+
+        # 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 = '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
+
+        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
+
+        if (not slice_spec or 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
+        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()))
+        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
 # 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)
-       else:
-               setns.proc_umount()
-               _,status = os.waitpid(pid,0)
-               exit(os.WEXITSTATUS(status))
+#                                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)
+        else:
+            setns.proc_umount()
+            _,status = os.waitpid(pid,0)
+            exit(os.WEXITSTATUS(status))
 
 if __name__ == '__main__':
-       main()
+    main()