Destroy container with snapshots & clone-snapshots

- This enables lxc-destroy to destroy a container with all its snapshots
  including clone-snapshots not located in the snaps/ folder.

Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

src/lxc/lxc_destroy.c

@@ -17,6 +17,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#define _GNU_SOURCE
 #include <lxc/lxccontainer.h>
 
 #include <stdio.h>
@@ -138,12 +139,79 @@ static int do_destroy(struct lxc_container *c)
 
 static int do_destroy_with_snapshots(struct lxc_container *c)
 {
-	if (!c->destroy_with_snapshots(c)) {
-		fprintf(stderr, "Destroying %s failed\n", my_args.name);
+	struct lxc_container *c1;
+	struct stat fbuf;
+	char path[MAXPATHLEN];
+	char *buf = NULL;
+	char *lxcpath = NULL;
+	char *lxcname = NULL;
+	char *scratch = NULL;
+	int fd;
+	int ret;
+	int counter = 0;
+
+	/* Destroy snapshots created with lxc-clone listed in lxc-snapshots. */
+	ret = snprintf(path, MAXPATHLEN, "%s/%s/lxc_snapshots", c->config_path, c->name);
+
+	fd = open(path, O_RDONLY | O_CLOEXEC);
+	if (fd > 0) {
+		ret = fstat(fd, &fbuf);
+		if (ret < 0) {
+			close(fd);
+			return -1;
+		}
+
+		/* Make sure that the string is \0 terminated. */
+		buf = calloc(fbuf.st_size + 1, sizeof(char));
+		if (!buf) {
+			SYSERROR("failed to allocate memory");
+			close(fd);
+			free(buf);
+			return -1;
+		}
+
+		ret = read(fd, buf, fbuf.st_size);
+		if (ret < 0) {
+			ERROR("could not read %s", path);
+			close(fd);
+			free(buf);
+			return -1;
+		}
+		close(fd);
+
+		while ((lxcpath = strtok_r(!counter ? buf : NULL, "\n", &scratch))) {
+			if (!(lxcname = strtok_r(NULL, "\n", &scratch)))
+				break;
+			c1 = lxc_container_new(lxcname, lxcpath);
+			if (!c1->destroy(c1)) {
+				fprintf(stderr, "Destroying snapshot %s of %s failed\n", lxcname, my_args.name);
+				lxc_container_put(c1);
+				free(buf);
+				return -1;
+			}
+			lxc_container_put(c1);
+			counter++;
+		}
+		free(buf);
+	}
+
+	/* Destroy snapshots located in the containers snap/ folder. */
+	ret = snprintf(path, MAXPATHLEN, "%s/%s/snaps", c->config_path, c->name);
+	if (ret < 0 || ret >= MAXPATHLEN)
 		return -1;
+	if (dir_exists(path)) {
+		if (!c->destroy_with_snapshots(c)) {
+			fprintf(stderr, "Destroying %s failed\n", my_args.name);
+			return -1;
+		}
+	} else {
+		if (!c->destroy(c)) {
+			fprintf(stderr, "Destroying %s failed\n", my_args.name);
+			return -1;
+		}
 	}
 
-	printf("Destroyed container including snapshots %s\n", my_args.name);
+	printf("Destroyed container %s including snapshots \n", my_args.name);
 
 	return 0;
 }