From: Sapan Bhatia Date: Wed, 19 Mar 2014 05:43:23 +0000 (-0400) Subject: Replaced lxcsu with slicesu. The latter supports hypervisors e.g. KVM X-Git-Tag: lxc-userspace-1.0-9~3 X-Git-Url: http://git.onelab.eu/?p=lxc-userspace.git;a=commitdiff_plain;h=958a51c139fd55a18d8ba07923801fdffcd91cbf Replaced lxcsu with slicesu. The latter supports hypervisors e.g. KVM --- diff --git a/slicesu b/slicesu new file mode 100644 index 0000000..15e5854 --- /dev/null +++ b/slicesu @@ -0,0 +1,310 @@ +#!/usr/bin/python + +import sys +import os +import setns +import pdb + +from argparse import ArgumentParser + +# 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 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 kvmsu(slice_name, args): + # Find MAC address of virt interface + ifstr = os.popen('/usr/bin/virsh domiflist %s'%slice_name).read().strip() + mac_address = ifstr.split()[-1] + + # Find IP address of virt interface + ipaddr_str = os.popen('arp -an | grep %s'%'78:2b:cb:2d:f0:60').read().strip() + ip_addr_part = ipaddr_str.split()[1] + if (ip_addr_part[0]=='(' and ip_addr_part[-1]==')'): + ip_addr = ip_addr_part[1:len(ip_addr_part)-1] + + os.execv('/usr/bin/ssh',['/usr/bin/ssh','-o','StrictHostKeyChecking=no','root@%s'%ip_addr,'"$@"']) + + +def lxcsu(slice_name, args): + # 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 = '/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 + + except: + print "Domain %s not found"%slice_name + exit(1) + + if not driver_pid or not init_pid: + print "Domain %s not started"%slice_name + exit(1) + + 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: + 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)) + + # 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) + # 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) + + + def chcontext (path): + retcod = setns.chcontext (path) + if retcod != 0: + print 'WARNING - setns(%s)=>%s (ignored)'%(path,retcod) + return retcod + + # 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)): + 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')): + 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) + + fork_pid = os.fork() + + def getuid (slicename): + import pwd + try: + return pwd.getpwnam(slicename).pw_uid + except: + return + + 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,'/bin/sh','--login',]+args.command_to_run + else: + # let's keep this check even though we don't use the uid + # as a way of checking the existence of the slice account + 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/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 + else: + 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'): + 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(fork_pid,0) + exit(os.WEXITSTATUS(status)) + +def main (): + parser = ArgumentParser() + parser.add_argument("-n", "--nonet", + action="store_true", dest="no_netns", default=False, + help="Don't enter network namespace") + parser.add_argument("-m", "--nomnt", + action="store_true", dest="no_mntns", default=False, + help="Don't enter mount namespace") + parser.add_argument("-p", "--nopid", + 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") + 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 + + try: + cmd = '/usr/bin/virsh dominfo %s'%slice_name + info = os.popen(cmd).read() + d = {} + + ostype = None + for line in info.split('\n'): + pair = line.split(':') + d[pair[0].strip()] = pair[1].strip() + if (pair[0].strip()=='OS Type'): + ostype = pair[1].strip() + break + except: + print "Domain %s not found"%slice_name + + is_kvm = ostype=='hvm' + + if (is_kvm): + kvmsu(slice_name, args) + else: + lxcsu(slice_name, args) + +if __name__ == '__main__': + main()