config : add lxc.hook.destroy option

doc/lxc.container.conf.sgml.in

@@ -1359,6 +1359,18 @@ mknod errno 0
           </listitem>
         </varlistentry>
       </variablelist>
+      <variablelist>
+        <varlistentry>
+          <term>
+            <option>lxc.hook.destroy</option>
+          </term>
+          <listitem>
+            <para>
+              A hook to be run when the container is destroyed.
+            </para>
+          </listitem>
+        </varlistentry>
+      </variablelist>
     </refsect2>
 
     <refsect2>

src/lxc/conf.c

@@ -163,7 +163,7 @@ return -1;
 #endif
 
 char *lxchook_names[NUM_LXC_HOOKS] = {
-	"pre-start", "pre-mount", "mount", "autodev", "start", "post-stop", "clone" };
+	"pre-start", "pre-mount", "mount", "autodev", "start", "post-stop", "clone", "destroy" };
 
 typedef int (*instantiate_cb)(struct lxc_handler *, struct lxc_netdev *);
 
@@ -3977,6 +3977,8 @@ int run_lxc_hooks(const char *name, char *hook, struct lxc_conf *conf,
 		which = LXCHOOK_POSTSTOP;
 	else if (strcmp(hook, "clone") == 0)
 		which = LXCHOOK_CLONE;
+	else if (strcmp(hook, "destroy") == 0)
+		which = LXCHOOK_DESTROY;
 	else
 		return -1;
 	lxc_list_for_each(it, &conf->hooks[which]) {
@@ -4605,4 +4607,4 @@ struct lxc_list *sort_cgroup_settings(struct lxc_list* cgroup_settings)
 	}
 
 	return result;
-}
\ No newline at end of file
+}

src/lxc/conf.h

@@ -279,7 +279,8 @@ enum {
  */
 enum lxchooks {
 	LXCHOOK_PRESTART, LXCHOOK_PREMOUNT, LXCHOOK_MOUNT, LXCHOOK_AUTODEV,
-	LXCHOOK_START, LXCHOOK_POSTSTOP, LXCHOOK_CLONE, NUM_LXC_HOOKS};
+	LXCHOOK_START, LXCHOOK_POSTSTOP, LXCHOOK_CLONE, LXCHOOK_DESTROY,
+	NUM_LXC_HOOKS};
 extern char *lxchook_names[NUM_LXC_HOOKS];
 
 struct saved_nic {

src/lxc/confile.c

@@ -132,6 +132,7 @@ static struct lxc_config_t config[] = {
 	{ "lxc.hook.start",           config_hook                 },
 	{ "lxc.hook.post-stop",       config_hook                 },
 	{ "lxc.hook.clone",           config_hook                 },
+	{ "lxc.hook.destroy",         config_hook                 },
 	{ "lxc.hook",                 config_hook                 },
 	{ "lxc.network.type",         config_network_type         },
 	{ "lxc.network.flags",        config_network_flags        },
@@ -1002,6 +1003,8 @@ static int config_hook(const char *key, const char *value,
 		return add_hook(lxc_conf, LXCHOOK_POSTSTOP, copy);
 	else if (strcmp(key, "lxc.hook.clone") == 0)
 		return add_hook(lxc_conf, LXCHOOK_CLONE, copy);
+	else if (strcmp(key, "lxc.hook.destroy") == 0)
+		return add_hook(lxc_conf, LXCHOOK_DESTROY, copy);
 	SYSERROR("Unknown key: %s", key);
 	free(copy);
 	return -1;

src/lxc/lxccontainer.c

@@ -2154,6 +2154,7 @@ static bool container_destroy(struct lxc_container *c)
 {
 	bool bret = false;
 	int ret;
+	struct lxc_conf *conf = c->lxc_conf;
 
 	if (!c || !do_lxcapi_is_defined(c))
 		return false;
@@ -2167,19 +2168,47 @@ static bool container_destroy(struct lxc_container *c)
 		goto out;
 	}
 
-	if (current_config && c->lxc_conf == current_config) {
+	if (!lxc_list_empty(&conf->hooks[LXCHOOK_DESTROY])) {
+		/* Start of environment variable setup for hooks */
+		if (setenv("LXC_NAME", c->name, 1)) {
+			SYSERROR("failed to set environment variable for container name");
+		}
+		if (setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
+			SYSERROR("failed to set environment variable for config path");
+		}
+		if (setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
+			SYSERROR("failed to set environment variable for rootfs mount");
+		}
+		if (setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
+			SYSERROR("failed to set environment variable for rootfs mount");
+		}
+		if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
+			SYSERROR("failed to set environment variable for console path");
+		}
+		if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
+			SYSERROR("failed to set environment variable for console log");
+		}
+		/* End of environment variable setup for hooks */
+
+		if (run_lxc_hooks(c->name, "destroy", conf, c->get_config_path(c), NULL)) {
+			ERROR("Error executing clone hook for %s", c->name);
+			goto out;
+		}
+	}
+
+	if (current_config && conf == current_config) {
 		current_config = NULL;
-		if (c->lxc_conf->logfd != -1) {
-			close(c->lxc_conf->logfd);
-			c->lxc_conf->logfd = -1;
+		if (conf->logfd != -1) {
+			close(conf->logfd);
+			conf->logfd = -1;
 		}
 	}
 
-	if (c->lxc_conf && c->lxc_conf->rootfs.path && c->lxc_conf->rootfs.mount) {
+	if (conf && conf->rootfs.path && conf->rootfs.mount) {
 		if (am_unpriv())
-			ret = userns_exec_1(c->lxc_conf, bdev_destroy_wrapper, c->lxc_conf);
+			ret = userns_exec_1(conf, bdev_destroy_wrapper, conf);
 		else
-			ret = do_bdev_destroy(c->lxc_conf);
+			ret = do_bdev_destroy(conf);
 		if (ret < 0) {
 			ERROR("Error destroying rootfs for %s", c->name);
 			goto out;
@@ -2192,7 +2221,7 @@ static bool container_destroy(struct lxc_container *c)
 	char *path = alloca(strlen(p1) + strlen(c->name) + 2);
 	sprintf(path, "%s/%s", p1, c->name);
 	if (am_unpriv())
-		ret = userns_exec_1(c->lxc_conf, lxc_rmdir_onedev_wrapper, path);
+		ret = userns_exec_1(conf, lxc_rmdir_onedev_wrapper, path);
 	else
 		ret = lxc_rmdir_onedev(path, "snaps");
 	if (ret < 0) {