From 5a3481ee8610f14bd8cf0fd241d068b6c65ee45b Mon Sep 17 00:00:00 2001 From: Sapan Bhatia Date: Mon, 17 Jun 2013 21:04:36 -0400 Subject: [PATCH] Changed interface to lxcsu. Now invoked as lxcsu command --- lxcsu | 168 ++------------------------------------------- lxcsu-internal | 181 +++++++++++++++++++++++++++++++++++++++++++++++++ vsh.c | 4 +- 3 files changed, 188 insertions(+), 165 deletions(-) create mode 100755 lxcsu-internal diff --git a/lxcsu b/lxcsu index 164344f..2ac7920 100755 --- a/lxcsu +++ b/lxcsu @@ -1,181 +1,23 @@ #!/usr/bin/python - -import setns import os import sys 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() - if debug: print "readelf output %s lines"%len(output) - 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 fs_dir) +LXCSU_INTERNAL='/usr/sbin/lxcsu-internal' 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="*") options = parser.parse_args() slice_name=options.slice_name - global debug - debug=options.debug - - 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'): - slice_spec = slice_path - arch = getarch('/proc/%s/exe'%pid) - if debug: print "setting arch",arch - 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' - if debug: print "WARNING: setting arch to default x86_64" - - # 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 options.netns): - setns.chcontext('/proc/%s/ns/net'%pid) - - if (not options.mntns): - setns.chcontext('/proc/%s/ns/mnt'%pid) - - if (not options.pidns): - setns.chcontext('/proc/%s/ns/pid'%pid) - - if (not os.access('/proc/self',0)): - 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() - - if (pid == 0): - cap_arg = '--drop='+drop_capabilities - - if (not options.root): - exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+options.command_to_run - else: - exec_args = [arch,'/usr/sbin/capsh','--','--login']+options.command_to_run + commands = options.command_to_run - if debug: - print "exec'ing" - for arg in exec_args: print ">%s<"%arg - os.environ['SHELL'] = '/bin/sh' - os.execv('/usr/bin/setarch',exec_args) - else: - _,status = os.waitpid(pid,0) - exit(os.WEXITSTATUS(status)) + exec_args = [LXCSU_INTERNAL,slice_name,'--'] + exec_args+=commands + os.execv(LXCSU_INTERNAL,exec_args) if __name__ == '__main__': main() diff --git a/lxcsu-internal b/lxcsu-internal new file mode 100755 index 0000000..164344f --- /dev/null +++ b/lxcsu-internal @@ -0,0 +1,181 @@ +#!/usr/bin/python + + +import setns +import os +import sys + +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() + if debug: print "readelf output %s lines"%len(output) + 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 fs_dir) + +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="*") + + options = parser.parse_args() + slice_name=options.slice_name + global debug + debug=options.debug + + 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'): + slice_spec = slice_path + arch = getarch('/proc/%s/exe'%pid) + if debug: print "setting arch",arch + 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' + if debug: print "WARNING: setting arch to default x86_64" + + # 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 options.netns): + setns.chcontext('/proc/%s/ns/net'%pid) + + if (not options.mntns): + setns.chcontext('/proc/%s/ns/mnt'%pid) + + if (not options.pidns): + setns.chcontext('/proc/%s/ns/pid'%pid) + + if (not os.access('/proc/self',0)): + 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() + + if (pid == 0): + cap_arg = '--drop='+drop_capabilities + + if (not options.root): + exec_args = [arch,'/usr/sbin/capsh',cap_arg,'--','--login']+options.command_to_run + else: + exec_args = [arch,'/usr/sbin/capsh','--','--login']+options.command_to_run + + if debug: + print "exec'ing" + for arg in exec_args: print ">%s<"%arg + os.environ['SHELL'] = '/bin/sh' + os.execv('/usr/bin/setarch',exec_args) + else: + _,status = os.waitpid(pid,0) + exit(os.WEXITSTATUS(status)) + +if __name__ == '__main__': + main() diff --git a/vsh.c b/vsh.c index 03e7566..7cda5fa 100644 --- a/vsh.c +++ b/vsh.c @@ -1,4 +1,4 @@ -/* Version 3 of vsh. Basically a wrapper around 'lxcsu -n -m ' - Sapan */ +/* Version 3 of vsh. Basically a wrapper around 'lxcsu-internal -n -m ' - Sapan */ #include #include @@ -14,7 +14,7 @@ #define PATH_MAX 4096 #endif -#define LXCSU_PATH "/usr/sbin/lxcsu" +#define LXCSU_PATH "/usr/sbin/lxcsu-internal" char* get_current_username (unsigned int uid) { -- 2.43.0