src/lxc/state.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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <unistd.h>
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <sys/param.h>
  32 #include <sys/stat.h>
  33 #include <sys/file.h>
  34
  35 #include <lxc/lxc.h>
  36 #include <lxc/log.h>
  37 #include <lxc/start.h>
  38 #include <lxc/cgroup.h>
  39 #include <lxc/monitor.h>
  40 #include "commands.h"
  41 #include "config.h"
  42
  43 lxc_log_define(lxc_state, lxc);
  44
  45 static char *strstate[] = {
  46         "STOPPED", "STARTING", "RUNNING", "STOPPING",
  47         "ABORTING", "FREEZING", "FROZEN", "THAWED",
  48 };
  49
  50 const char *lxc_state2str(lxc_state_t state)
  51 {
  52         if (state < STOPPED || state > MAX_STATE - 1)
  53                 return NULL;
  54         return strstate[state];
  55 }
  56
  57 lxc_state_t lxc_str2state(const char *state)
  58 {
  59         size_t len;
  60         lxc_state_t i;
  61         len = sizeof(strstate)/sizeof(strstate[0]);
  62         for (i = 0; i < len; i++)
  63                 if (!strcmp(strstate[i], state))
  64                         return i;
  65
  66         ERROR("invalid state '%s'", state);
  67         return -1;
  68 }
  69
  70 static lxc_state_t freezer_state(const char *name, const char *lxcpath)
  71 {
  72         char *nsgroup = NULL;
  73         char freezer[MAXPATHLEN];
  74         char status[MAXPATHLEN];
  75         FILE *file;
  76         int err;
  77
  78         err = lxc_cgroup_path_get(&nsgroup, "freezer", name, lxcpath);
  79         if (err)
  80                 goto fail;
  81
  82         err = snprintf(freezer, MAXPATHLEN, "%s/freezer.state", nsgroup);
  83         if (err < 0 || err >= MAXPATHLEN)
  84                 goto fail;
  85
  86         file = fopen(freezer, "r");
  87         if (!file)
  88                 goto fail;
  89
  90         err = fscanf(file, "%s", status);
  91         fclose(file);
  92
  93         if (err == EOF) {
  94                 SYSERROR("failed to read %s", freezer);
  95                 goto fail;
  96         }
  97
  98         return lxc_str2state(status);
  99
 100 fail:
 101         if (nsgroup)
 102                 free(nsgroup);
 103         return -1;
 104 }
 105
 106 lxc_state_t lxc_getstate(const char *name, const char *lxcpath)
 107 {
 108         lxc_state_t state = freezer_state(name, lxcpath);
 109         if (state != FROZEN && state != FREEZING)
 110                 state = lxc_cmd_get_state(name, lxcpath);
 111         return state;
 112 }
 113
 114 static int fillwaitedstates(const char *strstates, int *states)
 115 {
 116         char *token, *saveptr = NULL;
 117         char *strstates_dup = strdup(strstates);
 118         int state;
 119
 120         if (!strstates_dup)
 121                 return -1;
 122
 123         token = strtok_r(strstates_dup, "|", &saveptr);
 124         while (token) {
 125
 126                 state = lxc_str2state(token);
 127                 if (state < 0) {
 128                         free(strstates_dup);
 129                         return -1;
 130                 }
 131
 132                 states[state] = 1;
 133
 134                 token = strtok_r(NULL, "|", &saveptr);
 135         }
 136         free(strstates_dup);
 137         return 0;
 138 }
 139
 140 extern int lxc_wait(const char *lxcname, const char *states, int timeout, const char *lxcpath)
 141 {
 142         struct lxc_msg msg;
 143         int state, ret;
 144         int s[MAX_STATE] = { }, fd;
 145
 146         if (fillwaitedstates(states, s))
 147                 return -1;
 148
 149         if (lxc_monitord_spawn(lxcpath))
 150                 return -1;
 151
 152         fd = lxc_monitor_open(lxcpath);
 153         if (fd < 0)
 154                 return -1;
 155
 156         /*
 157          * if container present,
 158          * then check if already in requested state
 159          */
 160         ret = -1;
 161         state = lxc_getstate(lxcname, lxcpath);
 162         if (state < 0) {
 163                 goto out_close;
 164         } else if ((state >= 0) && (s[state])) {
 165                 ret = 0;
 166                 goto out_close;
 167         }
 168
 169         for (;;) {
 170                 int elapsed_time, curtime = 0;
 171                 struct timeval tv;
 172                 int stop = 0;
 173                 int retval;
 174
 175                 if (timeout != -1) {
 176                         retval = gettimeofday(&tv, NULL);
 177                         if (retval)
 178                                 goto out_close;
 179                         curtime = tv.tv_sec;
 180                 }
 181                 if (lxc_monitor_read_timeout(fd, &msg, timeout) < 0) {
 182                         /* try again if select interrupted by signal */
 183                         if (errno != EINTR)
 184                                 goto out_close;
 185                 }
 186
 187                 if (timeout != -1) {
 188                         retval = gettimeofday(&tv, NULL);
 189                         if (retval)
 190                                 goto out_close;
 191                         elapsed_time = tv.tv_sec - curtime;
 192                         if (timeout - elapsed_time <= 0)
 193                                 stop = 1;
 194                         timeout -= elapsed_time;
 195                 }
 196
 197                 if (strcmp(lxcname, msg.name)) {
 198                         if (stop) {
 199                                 ret = -2;
 200                                 goto out_close;
 201                         }
 202                         continue;
 203                 }
 204
 205                 switch (msg.type) {
 206                 case lxc_msg_state:
 207                         if (msg.value < 0 || msg.value >= MAX_STATE) {
 208                                 ERROR("Receive an invalid state number '%d'",
 209                                         msg.value);
 210                                 goto out_close;
 211                         }
 212
 213                         if (s[msg.value]) {
 214                                 ret = 0;
 215                                 goto out_close;
 216                         }
 217                         break;
 218                 default:
 219                         if (stop) {
 220                                 ret = -2;
 221                                 goto out_close;
 222                         }
 223                         /* just ignore garbage */
 224                         break;
 225                 }
 226         }
 227
 228 out_close:
 229         lxc_monitor_close(fd);
 230         return ret;
 231 }