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
  24 #ifndef _GNU_SOURCE
  25 #define _GNU_SOURCE 1
  26 #endif
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <sys/param.h>
  33 #include <sys/types.h>
  34 #include <unistd.h>
  35
  36 #include "cgroup.h"
  37 #include "commands.h"
  38 #include "config.h"
  39 #include "error.h"
  40 #include "log.h"
  41 #include "lxc.h"
  42 #include "monitor.h"
  43 #include "state.h"
  44 #include "string_utils.h"
  45
  46 lxc_log_define(freezer, lxc);
  47
  48 static int do_freeze_thaw(bool freeze, struct lxc_conf *conf, const char *name,
  49                           const char *lxcpath)
  50 {
  51         int ret;
  52         char v[100];
  53         struct cgroup_ops *cgroup_ops;
  54         const char *state;
  55         size_t state_len;
  56         lxc_state_t new_state = freeze ? FROZEN : THAWED;
  57
  58         state = lxc_state2str(new_state);
  59         state_len = strlen(state);
  60
  61         cgroup_ops = cgroup_init(conf);
  62         if (!cgroup_ops)
  63                 return -1;
  64
  65         ret = cgroup_ops->set(cgroup_ops, "freezer.state", state, name, lxcpath);
  66         if (ret < 0) {
  67                 cgroup_exit(cgroup_ops);
  68                 ERROR("Failed to %s %s",
  69                       (new_state == FROZEN ? "freeze" : "unfreeze"), name);
  70                 return -1;
  71         }
  72
  73         for (;;) {
  74                 ret = cgroup_ops->get(cgroup_ops, "freezer.state", v, sizeof(v),
  75                                       name, lxcpath);
  76                 if (ret < 0) {
  77                         cgroup_exit(cgroup_ops);
  78                         ERROR("Failed to get freezer state of %s", name);
  79                         return -1;
  80                 }
  81
  82                 v[sizeof(v) - 1] = '\0';
  83                 v[lxc_char_right_gc(v, strlen(v))] = '\0';
  84
  85                 ret = strncmp(v, state, state_len);
  86                 if (ret == 0) {
  87                         cgroup_exit(cgroup_ops);
  88                         lxc_cmd_serve_state_clients(name, lxcpath, new_state);
  89                         lxc_monitor_send_state(name, new_state, lxcpath);
  90                         return 0;
  91                 }
  92
  93                 sleep(1);
  94         }
  95 }
  96
  97 int lxc_freeze(struct lxc_conf *conf, const char *name, const char *lxcpath)
  98 {
  99         lxc_cmd_serve_state_clients(name, lxcpath, FREEZING);
 100         lxc_monitor_send_state(name, FREEZING, lxcpath);
 101         return do_freeze_thaw(true, conf, name, lxcpath);
 102 }
 103
 104 int lxc_unfreeze(struct lxc_conf *conf, const char *name, const char *lxcpath)
 105 {
 106         return do_freeze_thaw(false, conf, name, lxcpath);
 107 }