src/lxc/namespace.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2009
   5  *
   6  * Authors:
   7  * Daniel Lezcano <dlezcano at fr.ibm.com>
   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 <namespace.h>
  29
  30 #include <lxc/log.h>
  31
  32 lxc_log_define(lxc_namespace, lxc);
  33
  34 struct clone_arg {
  35         int (*fn)(void *);
  36         void *arg;
  37 };
  38
  39 static int do_clone(void *arg)
  40 {
  41         struct clone_arg *clone_arg = arg;
  42         return clone_arg->fn(clone_arg->arg);
  43 }
  44
  45 pid_t lxc_clone(int (*fn)(void *), void *arg, int flags)
  46 {
  47         struct clone_arg clone_arg = {
  48                 .fn = fn,
  49                 .arg = arg,
  50         };
  51
  52         long stack_size = sysconf(_SC_PAGESIZE);
  53         void *stack = alloca(stack_size) + stack_size;
  54         pid_t ret;
  55
  56 #ifdef __ia64__
  57         ret = __clone2(do_clone, stack,
  58                        stack_size, flags | SIGCHLD, &clone_arg);
  59 #else
  60         ret = clone(do_clone, stack, flags | SIGCHLD, &clone_arg);
  61 #endif
  62         if (ret < 0)
  63                 ERROR("failed to clone(0x%x): %s", flags, strerror(errno));
  64
  65         return ret;
  66 }