X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lxcsu;h=90491870ebfad43dc9aa4f20112af17b7f73096e;hb=b79fe6df7f6ce5c23fc82576f81622e8fe985043;hp=3c63f74413f4faf041d25ac26f6e0e9fb5fd1fb9;hpb=247503f76b815841ec5b567b7cc35d54225218c2;p=lxc-userspace.git diff --git a/lxcsu b/lxcsu index 3c63f74..9049187 100755 --- a/lxcsu +++ b/lxcsu @@ -3,16 +3,16 @@ 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 -def getarch(f): - output = os.popen('readelf -h %s 2>&1'%f).readlines() +def getarch(pid): + exe_filename='/proc/%s/exe'%pid + output = os.popen('readelf -h %s 2>&1'%exe_filename).readlines() classlines = [x for x in output if ('Class' in x.split(':')[0])] line = classlines[0] c = line.split(':')[1] @@ -21,8 +21,24 @@ def getarch(f): elif ('ELF32' in c): return 'i686' else: - raise Exception('Could not determine architecture') - + raise Exception('Could not determine architecture for pid %s'%pid) + +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) @@ -30,13 +46,13 @@ 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, @@ -64,6 +80,24 @@ 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 @@ -78,29 +112,29 @@ 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 init_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 + # some should be changed as well + except: - print "Error finding slice %s"%slice_name + 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): - print "Not started: %s"%slice_name + 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 + # driver_pid is always x86_64, we need to look at the VM's init process here + arch = getarch(init_pid) # Set sysctls specific to slice sysctls = [] @@ -115,49 +149,68 @@ def main (): 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 Exception,e: - if debug: print e - 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 Exception,e: - if debug: print e - 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 Exception,e: - if debug: print e - 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() + + 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) - 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) + def chcontext (path): + retcod = setns.chcontext (path) + if retcod != 0: + print 'WARNING - setns(%s)=>%s (ignored)'%(path,retcod) + return retcod - if (not args.mntns): - setns.chcontext('/proc/%s/ns/mnt'%pid) + # Use init_pid and not driver_pid to locate reference namespaces + ref_ns = "/proc/%s/ns/"%init_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)): @@ -179,6 +232,7 @@ 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" @@ -188,45 +242,23 @@ 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'): @@ -238,7 +270,7 @@ 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__':