src/lxc/freezer.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23 #include "config.h"
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <errno.h>
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <fcntl.h>
  31 #include <sys/types.h>
  32 #include <sys/param.h>
  33
  34 #include "cgroup.h"
  35 #include "commands.h"
  36 #include "error.h"
  37 #include "log.h"
  38 #include "lxc.h"
  39 #include "monitor.h"
  40 #include "state.h"
  41 #include "string_utils.h"
  42
  43 lxc_log_define(freezer, lxc);
  44
  45 static int do_freeze_thaw(bool freeze, const char *name, const char *lxcpath)
  46 {
  47         int ret;
  48         char v[100];
  49         struct cgroup_ops *cgroup_ops;
  50         const char *state = freeze ? "FROZEN" : "THAWED";
  51         size_t state_len = 6;
  52         lxc_state_t new_state = freeze ? FROZEN : THAWED;
  53
  54         cgroup_ops = cgroup_init(NULL);
  55         if (!cgroup_ops)
  56                 return -1;
  57
  58         ret = cgroup_ops->set(cgroup_ops, "freezer.state", state, name, lxcpath);
  59         if (ret < 0) {
  60                 cgroup_exit(cgroup_ops);
  61                 ERROR("Failed to freeze %s", name);
  62                 return -1;
  63         }
  64
  65         for (;;) {
  66                 ret = cgroup_ops->get(cgroup_ops, "freezer.state", v, sizeof(v), name, lxcpath);
  67                 if (ret < 0) {
  68                         cgroup_exit(cgroup_ops);
  69                         ERROR("Failed to get freezer state of %s", name);
  70                         return -1;
  71                 }
  72
  73                 v[99] = '\0';
  74                 v[lxc_char_right_gc(v, strlen(v))] = '\0';
  75
  76                 ret = strncmp(v, state, state_len);
  77                 if (ret == 0) {
  78                         cgroup_exit(cgroup_ops);
  79                         lxc_cmd_serve_state_clients(name, lxcpath, new_state);
  80                         lxc_monitor_send_state(name, new_state, lxcpath);
  81                         return 0;
  82                 }
  83
  84                 sleep(1);
  85         }
  86 }
  87
  88 int lxc_freeze(const char *name, const char *lxcpath)
  89 {
  90         lxc_cmd_serve_state_clients(name, lxcpath, FREEZING);
  91         lxc_monitor_send_state(name, FREEZING, lxcpath);
  92         return do_freeze_thaw(true, name, lxcpath);
  93 }
  94
  95 int lxc_unfreeze(const char *name, const char *lxcpath)
  96 {
  97         return do_freeze_thaw(false, name, lxcpath);
  98 }