src/lxc/checkpoint.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   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 #define _GNU_SOURCE
  24 #include <stdio.h>
  25 #undef _GNU_SOURCE
  26 #include <fcntl.h>
  27 #include <signal.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <unistd.h>
  31 #include <errno.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <sys/param.h>
  35 #include <sys/file.h>
  36 #include <netinet/in.h>
  37 #include <net/if.h>
  38
  39 #include "error.h"
  40 #include "lxc_plugin.h"
  41 #include <lxc.h>
  42
  43 #define MAXPIDLEN 20
  44
  45 int lxc_checkpoint(const char *name, const char *statefile,
  46                 unsigned long flags)
  47 {
  48         char init[MAXPATHLEN];
  49         char val[MAXPIDLEN];
  50         int fd, lock, ret = -1;
  51         size_t pid;
  52
  53         lock = lxc_get_lock(name);
  54         if (lock >= 0) {
  55                 lxc_put_lock(lock);
  56                 return -LXC_ERROR_ESRCH;
  57         }
  58
  59         if (lock < 0 && lock != -LXC_ERROR_EBUSY)
  60                 return lock;
  61
  62         snprintf(init, MAXPATHLEN, LXCPATH "/%s/init", name);
  63         fd = open(init, O_RDONLY);
  64         if (fd < 0) {
  65                 lxc_log_syserror("failed to open init file for %s", name);
  66                 goto out_close;
  67         }
  68
  69         if (read(fd, val, sizeof(val)) < 0) {
  70                 lxc_log_syserror("failed to read %s", init);
  71                 goto out_close;
  72         }
  73
  74         pid = atoi(val);
  75
  76         if (lxc_plugin_checkpoint(pid, statefile, flags) < 0) {
  77                 lxc_log_syserror("failed to checkpoint %zd", pid);
  78                 goto out_close;
  79         }
  80
  81         ret = 0;
  82
  83 out_close:
  84         close(fd);
  85         return ret;
  86 }