src/lxc/namespace.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2009
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23
  24 #include <unistd.h>
  25 #include <alloca.h>
  26 #include <errno.h>
  27 #include <signal.h>
  28 #include <sys/param.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <fcntl.h>
  32
  33 #include "namespace.h"
  34 #include "log.h"
  35
  36 lxc_log_define(lxc_namespace, lxc);
  37
  38 struct clone_arg {
  39         int (*fn)(void *);
  40         void *arg;
  41 };
  42
  43 static int do_clone(void *arg)
  44 {
  45         struct clone_arg *clone_arg = arg;
  46         return clone_arg->fn(clone_arg->arg);
  47 }
  48
  49 pid_t lxc_clone(int (*fn)(void *), void *arg, int flags)
  50 {
  51         struct clone_arg clone_arg = {
  52                 .fn = fn,
  53                 .arg = arg,
  54         };
  55
  56         long stack_size = sysconf(_SC_PAGESIZE);
  57         void *stack = alloca(stack_size);
  58         pid_t ret;
  59
  60 #ifdef __ia64__
  61         ret = __clone2(do_clone, stack,
  62                        stack_size, flags | SIGCHLD, &clone_arg);
  63 #else
  64         ret = clone(do_clone, stack  + stack_size, flags | SIGCHLD, &clone_arg);
  65 #endif
  66         if (ret < 0)
  67                 ERROR("failed to clone(0x%x): %s", flags, strerror(errno));
  68
  69         return ret;
  70 }
  71
  72 static char *namespaces_list[] = {
  73         "MOUNT", "PID", "UTSNAME", "IPC",
  74         "USER", "NETWORK"
  75 };
  76 static int cloneflags_list[] = {
  77         CLONE_NEWNS, CLONE_NEWPID, CLONE_NEWUTS, CLONE_NEWIPC,
  78         CLONE_NEWUSER, CLONE_NEWNET
  79 };
  80
  81 int lxc_namespace_2_cloneflag(char *namespace)
  82 {
  83         int i, len;
  84         len = sizeof(namespaces_list)/sizeof(namespaces_list[0]);
  85         for (i = 0; i < len; i++)
  86                 if (!strcmp(namespaces_list[i], namespace))
  87                         return cloneflags_list[i];
  88
  89         ERROR("invalid namespace name %s", namespace);
  90         return -1;
  91 }
  92
  93 int lxc_fill_namespace_flags(char *flaglist, int *flags)
  94 {
  95         char *token, *saveptr = NULL;
  96         int aflag;
  97
  98         if (!flaglist) {
  99                 ERROR("need at least one namespace to unshare");
 100                 return -1;
 101         }
 102
 103         token = strtok_r(flaglist, "|", &saveptr);
 104         while (token) {
 105
 106                 aflag = lxc_namespace_2_cloneflag(token);
 107                 if (aflag < 0)
 108                         return -1;
 109
 110                 *flags |= aflag;
 111
 112                 token = strtok_r(NULL, "|", &saveptr);
 113         }
 114         return 0;
 115 }