rsync: add new rsync functions

src/lxc/bdev/lxcrsync.c

@@ -139,3 +139,82 @@ int rsync_rootfs_wrapper(void *data)
 	struct rsync_data *arg = data;
 	return rsync_rootfs(arg);
 }
+
+/* new helpers */
+int lxc_rsync_exec_wrapper(void *data)
+{
+	struct rsync_data *arg = data;
+	return lxc_rsync(arg);
+}
+
+int lxc_rsync_exec(const char *src, const char *dest)
+{
+	int ret;
+	size_t l;
+	char *s;
+
+	l = strlen(src) + 2;
+	s = malloc(l);
+	if (!s)
+		return -1;
+
+	ret = snprintf(s, l, "%s", src);
+	if (ret < 0 || (size_t)ret >= l)
+		return -1;
+
+	s[l - 2] = '/';
+	s[l - 1] = '\0';
+
+	execlp("rsync", "rsync", "-aHXS", "--delete", s, dest, (char *)NULL);
+	return -1;
+}
+
+int lxc_rsync(struct rsync_data *data)
+{
+	int ret;
+	struct bdev *orig = data->orig, *new = data->new;
+	char *dest, *src;
+
+	ret = unshare(CLONE_NEWNS);
+	if (ret < 0) {
+		SYSERROR("Failed to unshare CLONE_NEWNS");
+		return -1;
+	}
+
+	ret = detect_shared_rootfs();
+	if (ret) {
+		ret = mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL);
+		if (ret < 0)
+			SYSERROR("Failed to make \"/\" a slave mount");
+	}
+
+	ret = orig->ops->mount(orig);
+	if (ret < 0) {
+		ERROR("Failed mounting \"%s\" on \"%s\"", orig->src, orig->dest);
+		return -1;
+	}
+
+	ret = new->ops->mount(new);
+	if (ret < 0) {
+		ERROR("Failed mounting \"%s\" onto \"%s\"", new->src, new->dest);
+		return -1;
+	}
+
+	ret = lxc_switch_uid_gid(0, 0);
+	if (ret < 0)
+		return -1;
+	ret = lxc_setgroups(0, NULL);
+	if (ret < 0)
+		return -1;
+
+	src = lxc_storage_get_path(orig->dest, orig->type);
+	dest = lxc_storage_get_path(new->dest, new->type);
+
+	ret = lxc_rsync_exec(src, dest);
+	if (ret < 0) {
+		ERROR("Failed to rsync from \"%s\" into \"%s\"", src, dest);
+		return -1;
+	}
+
+	return 0;
+}

src/lxc/bdev/lxcrsync.h

@@ -43,4 +43,9 @@ int rsync_delta(struct rsync_data_char *data);
 int rsync_rootfs(struct rsync_data *data);
 int rsync_rootfs_wrapper(void *data);
 
+/* new helpers */
+extern int lxc_rsync_exec_wrapper(void *data);
+extern int lxc_rsync_exec(const char *src, const char *dest);
+extern int lxc_rsync(struct rsync_data *data);
+
 #endif // __LXC_RSYNC_H