move back to a single source file (lxcsu) with a -i/--internal option, and an lxcsu...
Thierry Parmentelat [Mon, 8 Jul 2013 19:19:33 +0000 (21:19 +0200)]
lxcsu
lxcsu-internal [changed from file to symlink]

diff --git a/lxcsu b/lxcsu
index 742fc83..5756162 100755 (executable)
--- a/lxcsu
+++ b/lxcsu
 #!/usr/bin/python
 
-import os
 import sys
+import os
+import setns
 
 from argparse import ArgumentParser
 
-LXCSU_INTERNAL='/usr/sbin/lxcsu-internal'
+drop_capabilities='cap_sys_admin,cap_sys_boot,cap_sys_module'
+
+# 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 umount(fs_dir):
+    output = os.popen('/bin/umount %s 2>&1'%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 ("slice_name")
     parser.add_argument ("command_to_run",nargs="*")
 
-    options = parser.parse_args()
-    slice_name=options.slice_name
-    commands = options.command_to_run
-    if (not commands):
-        commands = ['/bin/sh']
+    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
+
+    # 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' ] + 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
+    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()
+                os.system('sysctl -w %s=%s'%(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()
+
+    
+
+    # 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)
+
+    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):
+            uid = getuid (slice_name)
+            if not uid:
+                print "lxcsu-internal 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
 
-    exec_args = [LXCSU_INTERNAL,slice_name,'--','-c']
-    exec_args+=commands
-    os.execv(LXCSU_INTERNAL,exec_args)
+        os.environ['SHELL'] = '/bin/sh'
+        os.environ['HOME'] = '/home/%s'%slice_name
+        os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
+        os.chdir("/home/%s"%(slice_name))
+        print 'lxcsu-internal: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()
deleted file mode 100755 (executable)
index e30358351fe4705ef0cd621cd2bae11e8315d84c..0000000000000000000000000000000000000000
+++ /dev/null
@@ -1,225 +0,0 @@
-#!/usr/bin/python
-
-
-import setns
-import os
-
-from argparse import ArgumentParser
-
-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')
-
-def umount(fs_dir):
-    output = os.popen('/bin/umount %s 2>&1'%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("-d","--debug",
-                        action='store_true', dest='debug', default=False,
-                        help="debug option")
-    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
-
-    try:
-        cmd = 'grep %s /proc/*/cgroup | grep freezer'%slice_name
-        output = os.popen(cmd).readlines()
-#        if debug: print "output of grep freezer has %s lines"%len(output)
-    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
-    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()
-                os.system('sysctl -w %s=%s'%(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()
-
-    
-
-    # cgroups is not yet LXC-safe, so we need to use the course 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)
-
-    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):
-            uid = getuid (slice_name)
-            if not uid:
-                print "lxcsu-internal 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'
-        os.environ['HOME'] = '/home/%s'%slice_name
-        os.environ['LD_PRELOAD'] = '/etc/planetlab/lib/bind_public.so'
-        os.chdir("/home/%s"%(slice_name))
-        if debug: print 'lxcsu-internal: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()
new file mode 120000 (symlink)
index 0000000000000000000000000000000000000000..2e16c03a2ceb121a4f0bcc8c3051b9429d15df9e
--- /dev/null
@@ -0,0 +1 @@
+lxcsu
\ No newline at end of file