X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lxcsu;h=85b1ff72826c38d005845c67ef5895a530c424fb;hb=df40f9604c78752536de9314f1f03744531d7915;hp=3c63f74413f4faf041d25ac26f6e0e9fb5fd1fb9;hpb=247503f76b815841ec5b567b7cc35d54225218c2;p=lxc-userspace.git diff --git a/lxcsu b/lxcsu index 3c63f74..85b1ff7 100755 --- a/lxcsu +++ b/lxcsu @@ -3,11 +3,10 @@ import sys import os import setns +import pdb 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 @@ -23,6 +22,22 @@ def getarch(f): 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) @@ -30,13 +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, @@ -85,22 +100,27 @@ def main (): 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 "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 + # xxx probably init_pid here too + arch = getarch('/proc/%s/exe'%driver_pid) # Set sysctls specific to slice sysctls = [] @@ -115,49 +135,68 @@ 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 +218,7 @@ 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" @@ -188,20 +228,7 @@ 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 + fork_pid = os.fork() def getuid (slicename): import pwd @@ -210,23 +237,22 @@ def main (): except: return - if (pid == 0): - cap_arg = '--drop='+drop_capabilities - + 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: 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,'/bin/sh','--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 +# 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 +264,7 @@ 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__':