Setting tag lxc-userspace-1.0-11
[lxc-userspace.git] / lxcsu
diff --git a/lxcsu b/lxcsu
index 5cba780..b05342a 100755 (executable)
--- a/lxcsu
+++ b/lxcsu
 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
 
-#################### should go into a separate libvirtsystemd.py
-# but we want to keep packaging simple for now
-
-# reproducing libvirt's systemd-oriented escaping mechanism
-# http://code.metager.de/source/xref/lib/virt/src/util/virsystemd.c
-# (see original code at the end of this file)
-
-def virSystemdEscapeName (name):
-    result=''
-    def ESCAPE(c,s):
-        # replace hex's output '0x..' into '\x..' 
-        return s+hex(ord(c)).replace('0','\\',1)
-    VALID_CHARS = \
-        "0123456789" + \
-        "abcdefghijklmnopqrstuvwxyz" + \
-        "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + \
-        ":-_.\\"
-    for c in name:
-        if c=='/': 
-            result += '-'
-        elif c in '-\\' or c not in VALID_CHARS:
-            result=ESCAPE(c,result)
-        else:
-            result += c
-    return result
-
-#35static void virSystemdEscapeName(virBufferPtr buf,
-#36                                 const char *name)
-#37{
-#38    static const char hextable[16] = "0123456789abcdef";
-#39
-#40#define ESCAPE(c)                                                       \
-#41    do {                                                                \
-#42        virBufferAddChar(buf, '\\');                                    \
-#43        virBufferAddChar(buf, 'x');                                     \
-#44        virBufferAddChar(buf, hextable[(c >> 4) & 15]);                 \
-#45        virBufferAddChar(buf, hextable[c & 15]);                        \
-#46    } while (0)
-#47
-#48#define VALID_CHARS                             \
-#49        "0123456789"                            \
-#50        "abcdefghijklmnopqrstuvwxyz"            \
-#51        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"            \
-#52        ":-_.\\"
-#53
-#54    if (*name == '.') {
-#55        ESCAPE(*name);
-#56        name++;
-#57    }
-#58
-#59    while (*name) {
-#60        if (*name == '/')
-#61            virBufferAddChar(buf, '-');
-#62        else if (*name == '-' ||
-#63                 *name == '\\' ||
-#64                 !strchr(VALID_CHARS, *name))
-#65            ESCAPE(*name);
-#66        else
-#67            virBufferAddChar(buf, *name);
-#68        name++;
-#69    }
-#70
-#71#undef ESCAPE
-#72#undef VALID_CHARS
-#73}
-
-def virSystemdMakeScopeName (name, drivername, partition):
-    result=''
-    result += virSystemdEscapeName (partition)
-    result += '-'
-    result += virSystemdEscapeName (drivername)
-    result += '\\x2d'
-    result += virSystemdEscapeName (name)
-    result += '.scope'
-    return result
-
-#76char *virSystemdMakeScopeName(const char *name,
-#77                              const char *drivername,
-#78                              const char *partition)
-#79{
-#80    virBuffer buf = VIR_BUFFER_INITIALIZER;
-#81
-#82    if (*partition == '/')
-#83        partition++;
-#84
-#85    virSystemdEscapeName(&buf, partition);
-#86    virBufferAddChar(&buf, '-');
-#87    virSystemdEscapeName(&buf, drivername);
-#88    virBufferAddLit(&buf, "\\x2d");
-#89    virSystemdEscapeName(&buf, name);
-#90    virBufferAddLit(&buf, ".scope");
-#91
-#92    if (virBufferError(&buf)) {
-#93        virReportOOMError();
-#94        return NULL;
-#95    }
-#96
-#97    return virBufferContentAndReset(&buf);
-#98}
-
-### our own additions
-import os.path
-def find_first_dir (candidates):
-    for candidate in candidates:
-        if os.path.isdir(candidate): return candidate
-    raise Exception,"Cannot find valid dir among\n" + "\n".join([" ->"+c for c in candidates])
-
-def find_sysfs_scope (subsystem, slice_name):
-    subsystem1=subsystem
-    subsystem2=subsystem
-    if subsystem=='cpuacct':
-        subsystem2='cpu,cpuacct'
-    candidates = [ 
-        # for f16 and our locally brewed libvirt 1.0.4
-        "/sys/fs/cgroup/%s/libvirt/lxc/%s"%(subsystem1, slice_name),
-        # f20 and libvirt 1.1.3
-        "/sys/fs/cgroup/%s/machine.slice/%s"%(subsystem2, 
-                                              virSystemdMakeScopeName(slice_name,'lxc','machine')),
-        ]
-    return find_first_dir (candidates)
-
-#################### end of libvirtsystemd.py
-
 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])]
@@ -170,13 +45,13 @@ def umount(fs_dir, opts=''):
 def main ():
     parser = ArgumentParser()
     parser.add_argument("-n", "--nonet",
-                                       action="store_true", dest="netns", default=False,
+                                       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,
+                                       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,
+                                       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,
@@ -204,6 +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
 
@@ -218,29 +111,29 @@ 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
-       pidnum = int(os.popen(cmd).read().rstrip())
+        # 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
+
     except:
         print "Domain %s not found"%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):
+    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 = []
@@ -255,7 +148,8 @@ def main ():
                sysctl_val = open(sysctl_file).read()
                sysctls.append((sysctl_file, sysctl_name, sysctl_val))
 
-    subdirs = get_cgroup_subdirs_for_pid(pid) 
+    # 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
@@ -297,21 +191,25 @@ def main ():
                 pass
             else:
                 if debug: print e 
-                print "Error assigning cgroup %s (%s) for slice %s"%(current_cgroup,pid, slice_name)
+                print "Error assigning cgroup %s (pid=%s) for slice %s"%(current_cgroup,driver_pid, 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)
+    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)):
@@ -333,6 +231,7 @@ def main ():
     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"
@@ -342,45 +241,23 @@ def main ():
         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'
         if os.path.exists('/etc/planetlab/lib/bind_public.so'):
@@ -392,7 +269,7 @@ def main ():
         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__':