src/lxc/lxccontainer.c

	lxccontainer.c revision afeecbba0359d2b4404cdf896e6b6d0b5a8443b0
/* liblxcapi
 *
 * Copyright © 2012 Serge Hallyn <serge.hallyn@ubuntu.com>.
 * Copyright © 2012 Canonical Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2, as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "lxc.h"
#include "state.h"
#include "lxccontainer.h"
#include "conf.h"
#include "config.h"
#include "confile.h"
#include "cgroup.h"
#include "commands.h"
#include "log.h"
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <lxc/utils.h>

lxc_log_define(lxc_container, lxc);

/* LOCKING
 * c->privlock protects the struct lxc_container from multiple threads.
 * c->slock protects the on-disk container data
 * NOTHING mutexes two independent programs with their own struct
 * lxc_container for the same c->name, between API calls.  For instance,
 * c->config_read(); c->start();  Between those calls, data on disk
 * could change (which shouldn't bother the caller unless for instance
 * the rootfs get moved).  c->config_read(); update; c->config_write();
 * Two such updaters could race.  The callers should therefore check their
 * results.  Trying to prevent that would necessarily expose us to deadlocks
 * due to hung callers.  So I prefer to keep the locks only within our own
 * functions, not across functions.
 *
 * If you're going to fork while holding a lxccontainer, increment
 * c->numthreads (under privlock) before forking.  When deleting,
 * decrement numthreads under privlock, then if it hits 0 you can delete.
 * Do not ever use a lxccontainer whose numthreads you did not bump.
 */

static void lxc_container_free(struct lxc_container *c)
{
    if (!c)
        return;

    if (c->configfile) {
        free(c->configfile);
        c->configfile = NULL;
    }
    if (c->error_string) {
        free(c->error_string);
        c->error_string = NULL;
    }
    if (c->slock) {
        sem_close(c->slock);
        c->slock = NULL;
    }
    if (c->privlock) {
        sem_destroy(c->privlock);
        free(c->privlock);
        c->privlock = NULL;
    }
    if (c->name) {
        free(c->name);
        c->name = NULL;
    }
    if (c->lxc_conf) {
        lxc_conf_free(c->lxc_conf);
        c->lxc_conf = NULL;
    }
    if (c->config_path) {
        free(c->config_path);
        c->config_path = NULL;
    }
    free(c);
}

int lxc_container_get(struct lxc_container *c)
{
    if (!c)
        return 0;

    if (lxclock(c->privlock, 0))
        return 0;
    if (c->numthreads < 1) {
        // bail without trying to unlock, bc the privlock is now probably
        // in freed memory
        return 0;
    }
    c->numthreads++;
    lxcunlock(c->privlock);
    return 1;
}

int lxc_container_put(struct lxc_container *c)
{
    if (!c)
        return -1;
    if (lxclock(c->privlock, 0))
        return -1;
    if (--c->numthreads < 1) {
        lxcunlock(c->privlock);
        lxc_container_free(c);
        return 1;
    }
    lxcunlock(c->privlock);
    return 0;
}

static bool file_exists(char *f)
{
    struct stat statbuf;

    return stat(f, &statbuf) == 0;
}

static bool lxcapi_is_defined(struct lxc_container *c)
{
    struct stat statbuf;
    bool ret = false;
    int statret;

    if (!c)
        return false;

    if (lxclock(c->privlock, 0))
        return false;
    if (!c->configfile)
        goto out;
    statret = stat(c->configfile, &statbuf);
    if (statret != 0)
        goto out;
    ret = true;

out:
    lxcunlock(c->privlock);
    return ret;
}

static const char *lxcapi_state(struct lxc_container *c)
{
    const char *ret;
    lxc_state_t s;

    if (!c)
        return NULL;
    if (lxclock(c->slock, 0))
        return NULL;
    s = lxc_getstate(c->name);
    ret = lxc_state2str(s);
    lxcunlock(c->slock);

    return ret;
}

static bool is_stopped_nolock(struct lxc_container *c)
{
    lxc_state_t s;
    s = lxc_getstate(c->name);
    return (s == STOPPED);
}

static bool lxcapi_is_running(struct lxc_container *c)
{
    const char *s;

    if (!c)
        return false;
    s = lxcapi_state(c);
    if (!s || strcmp(s, "STOPPED") == 0)
        return false;
    return true;
}

static bool lxcapi_freeze(struct lxc_container *c)
{
    int ret;
    if (!c)
        return false;

    if (lxclock(c->slock, 0))
        return false;
    ret = lxc_freeze(c->name);
    lxcunlock(c->slock);
    if (ret)
        return false;
    return true;
}

static bool lxcapi_unfreeze(struct lxc_container *c)
{
    int ret;
    if (!c)
        return false;

    if (lxclock(c->slock, 0))
        return false;
    ret = lxc_unfreeze(c->name);
    lxcunlock(c->slock);
    if (ret)
        return false;
    return true;
}

static pid_t lxcapi_init_pid(struct lxc_container *c)
{
    pid_t ret;
    if (!c)
        return -1;

    if (lxclock(c->slock, 0))
        return -1;
    ret = get_init_pid(c->name);
    lxcunlock(c->slock);
    return ret;
}

static bool load_config_locked(struct lxc_container *c, const char *fname)
{
    if (!c->lxc_conf)
        c->lxc_conf = lxc_conf_init();
    if (c->lxc_conf && !lxc_config_read(fname, c->lxc_conf))
        return true;
    return false;
}

static bool lxcapi_load_config(struct lxc_container *c, const char *alt_file)
{
    bool ret = false;
    const char *fname;
    if (!c)
        return false;

    fname = c->configfile;
    if (alt_file)
        fname = alt_file;
    if (!fname)
        return false;
    if (lxclock(c->slock, 0))
        return false;
    ret = load_config_locked(c, fname);
    lxcunlock(c->slock);
    return ret;
}

static void lxcapi_want_daemonize(struct lxc_container *c)
{
    if (!c)
        return;
    c->daemonize = 1;
}

static bool lxcapi_wait(struct lxc_container *c, const char *state, int timeout)
{
    int ret;

    if (!c)
        return false;

    ret = lxc_wait(c->name, state, timeout);
    return ret == 0;
}


static bool wait_on_daemonized_start(struct lxc_container *c)
{
    /* we'll probably want to make this timeout configurable? */
    int timeout = 5, ret, status;

    /*
     * our child is going to fork again, then exit.  reap the
     * child
     */
    ret = wait(&status);
    if (ret == -1 || !WIFEXITED(status) || WEXITSTATUS(status) != 0)
        DEBUG("failed waiting for first dual-fork child");
    return lxcapi_wait(c, "RUNNING", timeout);
}

/*
 * I can't decide if it'd be more convenient for callers if we accept '...',
 * or a null-terminated array (i.e. execl vs execv)
 */
static bool lxcapi_start(struct lxc_container *c, int useinit, char * const argv[])
{
    int ret;
    struct lxc_conf *conf;
    int daemonize = 0;
    char *default_args[] = {
        "/sbin/init",
        '\0',
    };

    /* container exists */
    if (!c)
        return false;
    /* container has been setup */
    if (!c->lxc_conf)
        return false;

    /* is this app meant to be run through lxcinit, as in lxc-execute? */
    if (useinit && !argv)
        return false;

    if (lxclock(c->privlock, 0))
        return false;
    conf = c->lxc_conf;
    daemonize = c->daemonize;
    lxcunlock(c->privlock);

    if (useinit) {
        ret = lxc_execute(c->name, argv, 1, conf);
        return ret == 0 ? true : false;
    }

    if (!argv)
        argv = default_args;

    /*
    * say, I'm not sure - what locks do we want here?  Any?
    * Is liblxc's locking enough here to protect the on disk
    * container?  We don't want to exclude things like lxc_info
    * while container is running...
    */
    if (daemonize) {
        if (!lxc_container_get(c))
            return false;
        pid_t pid = fork();
        if (pid < 0) {
            lxc_container_put(c);
            return false;
        }
        if (pid != 0)
            return wait_on_daemonized_start(c);
        /* second fork to be reparented by init */
        pid = fork();
        if (pid < 0) {
            SYSERROR("Error doing dual-fork");
            return false;
        }
        if (pid != 0)
            exit(0);
        /* like daemon(), chdir to / and redirect 0,1,2 to /dev/null */
        if (chdir("/")) {
            SYSERROR("Error chdir()ing to /.");
            return false;
        }
        close(0);
        close(1);
        close(2);
        open("/dev/null", O_RDONLY);
        open("/dev/null", O_RDWR);
        open("/dev/null", O_RDWR);
        setsid();
    }

    if (clearenv()) {
        SYSERROR("failed to clear environment");
        /* don't error out though */
    }

    if (putenv("container=lxc")) {
        fprintf(stderr, "failed to set environment variable");
        if (daemonize) {
            lxc_container_put(c);
            exit(1);
        } else {
            return false;
        }
    }

reboot:
    conf->reboot = 0;
    ret = lxc_start(c->name, argv, conf);

    if (conf->reboot) {
        INFO("container requested reboot");
        conf->reboot = 0;
        goto reboot;
    }

    if (daemonize) {
        lxc_container_put(c);
        exit (ret == 0 ? true : false);
    } else {
        return (ret == 0 ? true : false);
    }
}

/*
 * note there MUST be an ending NULL
 */
static bool lxcapi_startl(struct lxc_container *c, int useinit, ...)
{
    va_list ap;
    char **inargs = NULL, **temp;
    int n_inargs = 0;
    bool bret = false;

    /* container exists */
    if (!c)
        return false;

    /* build array of arguments if any */
    va_start(ap, useinit);
    while (1) {
        char *arg;
        arg = va_arg(ap, char *);
        if (!arg)
            break;
        n_inargs++;
        temp = realloc(inargs, n_inargs * sizeof(*inargs));
        if (!temp)
            goto out;
        inargs = temp;
        inargs[n_inargs - 1] = strdup(arg);  // not sure if it's safe not to copy
    }
    va_end(ap);

    /* add trailing NULL */
    if (n_inargs) {
        n_inargs++;
        temp = realloc(inargs, n_inargs * sizeof(*inargs));
        if (!temp)
            goto out;
        inargs = temp;
        inargs[n_inargs - 1] = NULL;
    }

    bret = lxcapi_start(c, useinit, inargs);

out:
    if (inargs) {
        int i;
        for (i = 0; i < n_inargs; i++) {
            if (inargs[i])
                free(inargs[i]);
        }
        free(inargs);
    }

    return bret;
}

static bool lxcapi_stop(struct lxc_container *c)
{
    int ret;

    if (!c)
        return false;

    ret = lxc_stop(c->name);

    return ret == 0;
}

static bool valid_template(char *t)
{
    struct stat statbuf;
    int statret;

    statret = stat(t, &statbuf);
    if (statret == 0)
        return true;
    return false;
}

/*
 * create the standard expected container dir
 */
static bool create_container_dir(struct lxc_container *c)
{
    char *s;
    int len, ret;

    len = strlen(c->config_path) + strlen(c->name) + 2;
    s = malloc(len);
    if (!s)
        return false;
    ret = snprintf(s, len, "%s/%s", c->config_path, c->name);
    if (ret < 0 || ret >= len) {
        free(s);
        return false;
    }
    ret = mkdir(s, 0755);
    if (ret) {
        if (errno == EEXIST)
            ret = 0;
        else
            SYSERROR("failed to create container path for %s\n", c->name);
    }
    free(s);
    return ret == 0;
}

/*
 * backing stores not (yet) supported
 * for ->create, argv contains the arguments to pass to the template,
 * terminated by NULL.  If no arguments, you can just pass NULL.
 */
static bool lxcapi_create(struct lxc_container *c, char *t, char *const argv[])
{
    bool bret = false;
    pid_t pid;
    int ret, status;
    char *tpath = NULL;
    int len, nargs = 0;
    char **newargv;

    if (!c)
        return false;

    len = strlen(LXCTEMPLATEDIR) + strlen(t) + strlen("/lxc-") + 1;
    tpath = malloc(len);
    if (!tpath)
        return false;
    ret = snprintf(tpath, len, "%s/lxc-%s", LXCTEMPLATEDIR, t);
    if (ret < 0 || ret >= len)
        goto out;
    if (!valid_template(tpath)) {
        ERROR("bad template: %s\n", t);
        goto out;
    }

    if (!create_container_dir(c))
        goto out;

    if (!c->save_config(c, NULL)) {
        ERROR("failed to save starting configuration for %s\n", c->name);
        goto out;
    }

    /* we're going to fork.  but since we'll wait for our child, we
       don't need to lxc_container_get */

    if (lxclock(c->slock, 0)) {
        ERROR("failed to grab global container lock for %s\n", c->name);
        goto out;
    }

    pid = fork();
    if (pid < 0) {
        SYSERROR("failed to fork task for container creation template\n");
        goto out_unlock;
    }

    if (pid == 0) { // child
        char *patharg, *namearg;
        int i;

        close(0);
        close(1);
        close(2);
        open("/dev/null", O_RDONLY);
        open("/dev/null", O_RDWR);
        open("/dev/null", O_RDWR);

        /*
         * create our new array, pre-pend the template name and
         * base args
         */
        if (argv)
            for (; argv[nargs]; nargs++) ;
        nargs += 3;  // template, path and name args
        newargv = malloc(nargs * sizeof(*newargv));
        if (!newargv)
            exit(1);
        newargv[0] = t;

        len = strlen(c->config_path) + strlen(c->name) + strlen("--path=") + 2;
        patharg = malloc(len);
        if (!patharg)
            exit(1);
        ret = snprintf(patharg, len, "--path=%s/%s", c->config_path, c->name);
        if (ret < 0 || ret >= len)
            exit(1);
        newargv[1] = patharg;
        len = strlen("--name=") + strlen(c->name) + 1;
        namearg = malloc(len);
        if (!namearg)
            exit(1);
        ret = snprintf(namearg, len, "--name=%s", c->name);
        if (ret < 0 || ret >= len)
            exit(1);
        newargv[2] = namearg;

        /* add passed-in args */
        if (argv)
            for (i = 3; i < nargs; i++)
                newargv[i] = argv[i-3];

        /* add trailing NULL */
        nargs++;
        newargv = realloc(newargv, nargs * sizeof(*newargv));
        if (!newargv)
            exit(1);
        newargv[nargs - 1] = NULL;

        /* execute */
        ret = execv(tpath, newargv);
        SYSERROR("failed to execute template %s", tpath);
        exit(1);
    }

again:
    ret = waitpid(pid, &status, 0);
    if (ret == -1) {
        if (errno == -EINTR)
            goto again;
        SYSERROR("waitpid failed");
        goto out_unlock;
    }
    if (ret != pid)
        goto again;
    if (!WIFEXITED(status))  { // did not exit normally
        // we could set an error code and string inside the
        // container_struct here if we like
        ERROR("container creation template exited abnormally\n");
        goto out_unlock;
    }

    if (WEXITSTATUS(status) != 0) {
        ERROR("container creation template for %s exited with %d\n",
              c->name, WEXITSTATUS(status));
        goto out_unlock;
    }

    // now clear out the lxc_conf we have, reload from the created
    // container
    if (c->lxc_conf)
        lxc_conf_free(c->lxc_conf);
    c->lxc_conf = NULL;
    bret = load_config_locked(c, c->configfile);

out_unlock:
    lxcunlock(c->slock);
out:
    if (tpath)
        free(tpath);
    return bret;
}

static bool lxcapi_shutdown(struct lxc_container *c, int timeout)
{
    bool retv;
    pid_t pid;

    if (!c)
        return false;

    if (!timeout)
        timeout = -1;
    if (!c->is_running(c))
        return true;
    pid = c->init_pid(c);
    if (pid <= 0)
        return true;
    kill(pid, SIGPWR);
    retv = c->wait(c, "STOPPED", timeout);
    if (!retv && timeout > 0) {
        c->stop(c);
        retv = c->wait(c, "STOPPED", 0); // 0 means don't wait
    }
    return retv;
}

static bool lxcapi_createl(struct lxc_container *c, char *t, ...)
{
    bool bret = false;
    char **args = NULL, **temp;
    va_list ap;
    int nargs = 0;

    if (!c)
        return false;

    /*
     * since we're going to wait for create to finish, I don't think we
     * need to get a copy of the arguments.
     */
    va_start(ap, t);
    while (1) {
        char *arg;
        arg = va_arg(ap, char *);
        if (!arg)
            break;
        nargs++;
        temp = realloc(args, (nargs+1) * sizeof(*args));
        if (!temp)
            goto out;
        args = temp;
        args[nargs - 1] = arg;
    }
    va_end(ap);
    args[nargs] = NULL;

    bret = c->create(c, t, args);

out:
    if (args)
        free(args);
    return bret;
}

static bool lxcapi_clear_config_item(struct lxc_container *c, const char *key)
{
    int ret;

    if (!c || !c->lxc_conf)
        return false;
    if (lxclock(c->privlock, 0)) {
        return false;
    }
    ret = lxc_clear_config_item(c->lxc_conf, key);
    lxcunlock(c->privlock);
    return ret == 0;
}

static int lxcapi_get_config_item(struct lxc_container *c, const char *key, char *retv, int inlen)
{
    int ret;

    if (!c || !c->lxc_conf)
        return -1;
    if (lxclock(c->privlock, 0)) {
        return -1;
    }
    ret = lxc_get_config_item(c->lxc_conf, key, retv, inlen);
    lxcunlock(c->privlock);
    return ret;
}

static int lxcapi_get_keys(struct lxc_container *c, const char *key, char *retv, int inlen)
{
    if (!key)
        return lxc_listconfigs(retv, inlen);
    /*
     * Support 'lxc.network.<idx>', i.e. 'lxc.network.0'
     * This is an intelligent result to show which keys are valid given
     * the type of nic it is
     */
    if (!c || !c->lxc_conf)
        return -1;
    if (lxclock(c->privlock, 0))
        return -1;
    int ret = -1;
    if (strncmp(key, "lxc.network.", 12) == 0)
        ret =  lxc_list_nicconfigs(c->lxc_conf, key, retv, inlen);
    lxcunlock(c->privlock);
    return ret;
}


/* default config file - should probably come through autoconf */
#define LXC_DEFAULT_CONFIG "/etc/lxc/default.conf"
static bool lxcapi_save_config(struct lxc_container *c, const char *alt_file)
{
    if (!alt_file)
        alt_file = c->configfile;
    if (!alt_file)
        return false;  // should we write to stdout if no file is specified?
    if (!c->lxc_conf)
        if (!c->load_config(c, LXC_DEFAULT_CONFIG)) {
            ERROR("Error loading default configuration file %s while saving %s\n", LXC_DEFAULT_CONFIG, c->name);
            return false;
        }

    FILE *fout = fopen(alt_file, "w");
    if (!fout)
        return false;
    if (lxclock(c->privlock, 0)) {
        fclose(fout);
        return false;
    }
    write_config(fout, c->lxc_conf);
    fclose(fout);
    lxcunlock(c->privlock);
    return true;
}

static bool lxcapi_destroy(struct lxc_container *c)
{
    pid_t pid;
    int ret, status;

    if (!c)
        return false;

    pid = fork();
    if (pid < 0)
        return false;
    if (pid == 0) { // child
        ret = execlp("lxc-destroy", "lxc-destroy", "-n", c->name, NULL);
        perror("execl");
        exit(1);
    }

again:
    ret = waitpid(pid, &status, 0);
    if (ret == -1) {
        if (errno == -EINTR)
            goto again;
        perror("waitpid");
        return false;
    }
    if (ret != pid)
        goto again;
    if (!WIFEXITED(status))  { // did not exit normally
        // we could set an error code and string inside the
        // container_struct here if we like
        return false;
    }

    return WEXITSTATUS(status) == 0;
}

static bool lxcapi_set_config_item(struct lxc_container *c, const char *key, const char *v)
{
    int ret;
    bool b = false;
    struct lxc_config_t *config;

    if (!c)
        return false;

    if (lxclock(c->privlock, 0))
        return false;

    if (!c->lxc_conf)
        c->lxc_conf = lxc_conf_init();
    if (!c->lxc_conf)
        goto err;
    config = lxc_getconfig(key);
    if (!config)
        goto err;
    ret = config->cb(key, v, c->lxc_conf);
    if (!ret)
        b = true;

err:
    lxcunlock(c->privlock);
    return b;
}

static char *lxcapi_config_file_name(struct lxc_container *c)
{
    if (!c || !c->configfile)
        return NULL;
    return strdup(c->configfile);
}

static const char *lxcapi_get_config_path(struct lxc_container *c)
{
    if (!c || !c->config_path)
        return NULL;
    return (const char *)(c->config_path);
}

/*
 * not for export
 * Just recalculate the c->configfile based on the
 * c->config_path, which must be set.
 * The lxc_container must be locked or not yet public.
 */
static bool set_config_filename(struct lxc_container *c)
{
    char *newpath;
    int len, ret;

    if (!c->config_path)
        return false;

    /* $lxc_path + "/" + c->name + "/" + "config" + '\0' */
    len = strlen(c->config_path) + strlen(c->name) + strlen("config") + 3;
    newpath = malloc(len);
    if (!newpath)
        return false;

    ret = snprintf(newpath, len, "%s/%s/config", c->config_path, c->name);
    if (ret < 0 || ret >= len) {
        fprintf(stderr, "Error printing out config file name\n");
        free(newpath);
        return false;
    }

    if (c->configfile)
        free(c->configfile);
    c->configfile = newpath;

    return true;
}

static bool lxcapi_set_config_path(struct lxc_container *c, const char *path)
{
    char *p;
    bool b = false;
    char *oldpath = NULL;

    if (!c)
        return b;

    if (lxclock(c->privlock, 0))
        return b;

    p = strdup(path);
    if (!p) {
        ERROR("Out of memory setting new lxc path");
        goto err;
    }

    b = true;
    if (c->config_path)
        oldpath = c->config_path;
    c->config_path = p;

    /* Since we've changed the config path, we have to change the
     * config file name too */
    if (!set_config_filename(c)) {
        ERROR("Out of memory setting new config filename");
        b = false;
        free(c->config_path);
        c->config_path = oldpath;
        oldpath = NULL;
    }
err:
    if (oldpath)
        free(oldpath);
    lxcunlock(c->privlock);
    return b;
}


static bool lxcapi_set_cgroup_item(struct lxc_container *c, const char *subsys, const char *value)
{
    int ret;
    bool b = false;

    if (!c)
        return false;

    if (lxclock(c->privlock, 0))
        return false;

    if (is_stopped_nolock(c))
        goto err;

    ret = lxc_cgroup_set(c->name, subsys, value);
    if (!ret)
        b = true;
err:
    lxcunlock(c->privlock);
    return b;
}

static int lxcapi_get_cgroup_item(struct lxc_container *c, const char *subsys, char *retv, int inlen)
{
    int ret = -1;

    if (!c || !c->lxc_conf)
        return -1;

    if (lxclock(c->privlock, 0))
        return -1;

    if (is_stopped_nolock(c))
        goto out;

    ret = lxc_cgroup_get(c->name, subsys, retv, inlen);

out:
    lxcunlock(c->privlock);
    return ret;
}


struct lxc_container *lxc_container_new(const char *name, const char *configpath)
{
    struct lxc_container *c;

    c = malloc(sizeof(*c));
    if (!c) {
        fprintf(stderr, "failed to malloc lxc_container\n");
        return NULL;
    }
    memset(c, 0, sizeof(*c));

    if (configpath)
        c->config_path = strdup(configpath);
    else
        c->config_path = default_lxc_path();

    if (!c->config_path) {
        fprintf(stderr, "Out of memory");
        goto err;
    }

    c->name = malloc(strlen(name)+1);
    if (!c->name) {
        fprintf(stderr, "Error allocating lxc_container name\n");
        goto err;
    }
    strcpy(c->name, name);

    c->numthreads = 1;
    c->slock = lxc_newlock(name);
    if (!c->slock) {
        fprintf(stderr, "failed to create lock\n");
        goto err;
    }

    c->privlock = lxc_newlock(NULL);
    if (!c->privlock) {
        fprintf(stderr, "failed to alloc privlock\n");
        goto err;
    }

    if (!set_config_filename(c)) {
        fprintf(stderr, "Error allocating config file pathname\n");
        goto err;
    }

    if (file_exists(c->configfile))
        lxcapi_load_config(c, NULL);

    // assign the member functions
    c->is_defined = lxcapi_is_defined;
    c->state = lxcapi_state;
    c->is_running = lxcapi_is_running;
    c->freeze = lxcapi_freeze;
    c->unfreeze = lxcapi_unfreeze;
    c->init_pid = lxcapi_init_pid;
    c->load_config = lxcapi_load_config;
    c->want_daemonize = lxcapi_want_daemonize;
    c->start = lxcapi_start;
    c->startl = lxcapi_startl;
    c->stop = lxcapi_stop;
    c->config_file_name = lxcapi_config_file_name;
    c->wait = lxcapi_wait;
    c->set_config_item = lxcapi_set_config_item;
    c->destroy = lxcapi_destroy;
    c->save_config = lxcapi_save_config;
    c->get_keys = lxcapi_get_keys;
    c->create = lxcapi_create;
    c->createl = lxcapi_createl;
    c->shutdown = lxcapi_shutdown;
    c->clear_config_item = lxcapi_clear_config_item;
    c->get_config_item = lxcapi_get_config_item;
    c->get_cgroup_item = lxcapi_get_cgroup_item;
    c->set_cgroup_item = lxcapi_set_cgroup_item;
    c->get_config_path = lxcapi_get_config_path;
    c->set_config_path = lxcapi_set_config_path;

    /* we'll allow the caller to update these later */
    if (lxc_log_init(NULL, "none", NULL, "lxc_container", 0)) {
        fprintf(stderr, "failed to open log\n");
        goto err;
    }

    return c;

err:
    lxc_container_free(c);
    return NULL;
}

int lxc_get_wait_states(const char **states)
{
    int i;

    if (states)
        for (i=0; i<MAX_STATE; i++)
            states[i] = lxc_state2str(i);
    return MAX_STATE;
}