Split bdev into modules: lxcrsync

The functions:

        - do_rsync();
        - rsync_delta();
        - rsync_delta_wrapper();
        - rsync_rootfs();
        - rsync_rootfs_wrapper();

and the structs

        - struct rsync_data;
        - struct rsync_data_char;

move from bdev.{c,h} to lxcrsync.{c.h}. All functions previously declared as
static become public.

lxcrsync.{c,h} should allow for a reasonable amount of abstraction regarding
our rsync functions. Some of the functions could easily be abstracted.

Adapt Makefile.am to include lxcrsync.{c,h}.

Signed-off-by: Christian Brauner <christian.brauner@mailbox.org>

src/lxc/Makefile.am

@@ -9,6 +9,7 @@ noinst_HEADERS = \
 	bdev/bdev.h \
 	bdev/lxcbtrfs.h \
 	bdev/lxcoverlay.h \
+	bdev/lxcrsync.h \
 	caps.h \
 	cgroup.h \
 	conf.h \

src/lxc/bdev/bdev.c

@@ -53,9 +53,10 @@
 #include "error.h"
 #include "log.h"
 #include "lxc.h"
-#include "lxclock.h"
 #include "lxcbtrfs.h"
+#include "lxclock.h"
 #include "lxcoverlay.h"
+#include "lxcrsync.h"
 #include "namespace.h"
 #include "parse.h"
 #include "utils.h"
@@ -77,32 +78,6 @@
 
 lxc_log_define(bdev, lxc);
 
-/* the bulk of this needs to become a common helper */
-int do_rsync(const char *src, const char *dest)
-{
-	// call out to rsync
-	pid_t pid;
-	char *s;
-	size_t l;
-
-	pid = fork();
-	if (pid < 0)
-		return -1;
-	if (pid > 0)
-		return wait_for_pid(pid);
-
-	l = strlen(src) + 2;
-	s = malloc(l);
-	if (!s)
-		exit(1);
-	strcpy(s, src);
-	s[l-2] = '/';
-	s[l-1] = '\0';
-
-	execlp("rsync", "rsync", "-aHX", "--delete", s, dest, (char *)NULL);
-	exit(1);
-}
-
 /* the bulk of this needs to become a common helper */
 char *dir_new_path(char *src, const char *oldname, const char *name,
 		   const char *oldpath, const char *lxcpath)
@@ -1641,32 +1616,6 @@ static const struct bdev_ops loop_ops = {
 	.can_backup = true,
 };
 
-static int rsync_delta(struct rsync_data_char *data)
-{
-	if (setgid(0) < 0) {
-		ERROR("Failed to setgid to 0");
-		return -1;
-	}
-	if (setgroups(0, NULL) < 0)
-		WARN("Failed to clear groups");
-	if (setuid(0) < 0) {
-		ERROR("Failed to setuid to 0");
-		return -1;
-	}
-	if (do_rsync(data->src, data->dest) < 0) {
-		ERROR("rsyncing %s to %s", data->src, data->dest);
-		return -1;
-	}
-
-	return 0;
-}
-
-static int rsync_delta_wrapper(void *data)
-{
-	struct rsync_data_char *arg = data;
-	return rsync_delta(arg);
-}
-
 /* overlay */
 static const struct bdev_ops ovl_ops = {
 	.detect = &ovl_detect,
@@ -2365,60 +2314,6 @@ struct bdev *bdev_init(struct lxc_conf *conf, const char *src, const char *dst,
 	return bdev;
 }
 
-struct rsync_data {
-	struct bdev *orig;
-	struct bdev *new;
-};
-
-static int rsync_rootfs(struct rsync_data *data)
-{
-	struct bdev *orig = data->orig,
-		    *new = data->new;
-
-	if (unshare(CLONE_NEWNS) < 0) {
-		SYSERROR("unshare CLONE_NEWNS");
-		return -1;
-	}
-	if (detect_shared_rootfs()) {
-		if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL)) {
-			SYSERROR("Failed to make / rslave");
-			ERROR("Continuing...");
-		}
-	}
-
-	// If not a snapshot, copy the fs.
-	if (orig->ops->mount(orig) < 0) {
-		ERROR("failed mounting %s onto %s", orig->src, orig->dest);
-		return -1;
-	}
-	if (new->ops->mount(new) < 0) {
-		ERROR("failed mounting %s onto %s", new->src, new->dest);
-		return -1;
-	}
-	if (setgid(0) < 0) {
-		ERROR("Failed to setgid to 0");
-		return -1;
-	}
-	if (setgroups(0, NULL) < 0)
-		WARN("Failed to clear groups");
-	if (setuid(0) < 0) {
-		ERROR("Failed to setuid to 0");
-		return -1;
-	}
-	if (do_rsync(orig->dest, new->dest) < 0) {
-		ERROR("rsyncing %s to %s", orig->src, new->src);
-		return -1;
-	}
-
-	return 0;
-}
-
-static int rsync_rootfs_wrapper(void *data)
-{
-	struct rsync_data *arg = data;
-	return rsync_rootfs(arg);
-}
-
 bool bdev_is_dir(struct lxc_conf *conf, const char *path)
 {
 	struct bdev *orig = bdev_init(conf, path, NULL, NULL);

src/lxc/bdev/bdev.h

@@ -134,9 +134,4 @@ void detach_block_device(struct lxc_conf *conf);
 
 bool rootfs_is_blockdev(struct lxc_conf *conf);
 
-struct rsync_data_char {
-	char *src;
-	char *dest;
-};
-
 #endif // __LXC_BDEV_H

src/lxc/bdev/lxcbtrfs.c

@@ -37,6 +37,7 @@
 #include "bdev.h"
 #include "log.h"
 #include "lxcbtrfs.h"
+#include "lxcrsync.h"
 #include "utils.h"
 
 lxc_log_define(btrfs, lxc);

src/lxc/bdev/lxcrsync.c

@@ -0,0 +1,143 @@
+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2008
+ *
+ * Authors:
+ * Daniel Lezcano <daniel.lezcano at free.fr>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#define _GNU_SOURCE
+#include <grp.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/mount.h>
+
+#include "bdev.h"
+#include "log.h"
+#include "lxcbtrfs.h"
+#include "lxcrsync.h"
+#include "utils.h"
+
+lxc_log_define(lxcrsync, lxc);
+
+/* the bulk of this needs to become a common helper */
+int do_rsync(const char *src, const char *dest)
+{
+	// call out to rsync
+	pid_t pid;
+	char *s;
+	size_t l;
+
+	pid = fork();
+	if (pid < 0)
+		return -1;
+	if (pid > 0)
+		return wait_for_pid(pid);
+
+	l = strlen(src) + 2;
+	s = malloc(l);
+	if (!s)
+		exit(1);
+	strcpy(s, src);
+	s[l-2] = '/';
+	s[l-1] = '\0';
+
+	execlp("rsync", "rsync", "-aHX", "--delete", s, dest, (char *)NULL);
+	exit(1);
+}
+
+int rsync_delta(struct rsync_data_char *data)
+{
+	if (setgid(0) < 0) {
+		ERROR("Failed to setgid to 0");
+		return -1;
+	}
+	if (setgroups(0, NULL) < 0)
+		WARN("Failed to clear groups");
+	if (setuid(0) < 0) {
+		ERROR("Failed to setuid to 0");
+		return -1;
+	}
+	if (do_rsync(data->src, data->dest) < 0) {
+		ERROR("rsyncing %s to %s", data->src, data->dest);
+		return -1;
+	}
+
+	return 0;
+}
+
+int rsync_delta_wrapper(void *data)
+{
+	struct rsync_data_char *arg = data;
+	return rsync_delta(arg);
+}
+
+int rsync_rootfs(struct rsync_data *data)
+{
+	struct bdev *orig = data->orig,
+		    *new = data->new;
+
+	if (unshare(CLONE_NEWNS) < 0) {
+		SYSERROR("unshare CLONE_NEWNS");
+		return -1;
+	}
+	if (detect_shared_rootfs()) {
+		if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL)) {
+			SYSERROR("Failed to make / rslave");
+			ERROR("Continuing...");
+		}
+	}
+
+	// If not a snapshot, copy the fs.
+	if (orig->ops->mount(orig) < 0) {
+		ERROR("failed mounting %s onto %s", orig->src, orig->dest);
+		return -1;
+	}
+	if (new->ops->mount(new) < 0) {
+		ERROR("failed mounting %s onto %s", new->src, new->dest);
+		return -1;
+	}
+	if (setgid(0) < 0) {
+		ERROR("Failed to setgid to 0");
+		return -1;
+	}
+	if (setgroups(0, NULL) < 0)
+		WARN("Failed to clear groups");
+	if (setuid(0) < 0) {
+		ERROR("Failed to setuid to 0");
+		return -1;
+	}
+	if (do_rsync(orig->dest, new->dest) < 0) {
+		ERROR("rsyncing %s to %s", orig->src, new->src);
+		return -1;
+	}
+
+	return 0;
+}
+
+int rsync_rootfs_wrapper(void *data)
+{
+	struct rsync_data *arg = data;
+	return rsync_rootfs(arg);
+}
+

src/lxc/bdev/lxcrsync.h

@@ -0,0 +1,46 @@
+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2008
+ *
+ * Authors:
+ * Daniel Lezcano <daniel.lezcano at free.fr>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef __LXC_RSYNC_H
+#define __LXC_RSYNC_H
+
+#define _GNU_SOURCE
+#include <stdio.h>
+
+struct rsync_data {
+	struct bdev *orig;
+	struct bdev *new;
+};
+
+struct rsync_data_char {
+	char *src;
+	char *dest;
+};
+
+int do_rsync(const char *src, const char *dest);
+int rsync_delta_wrapper(void *data);
+int rsync_delta(struct rsync_data_char *data);
+int rsync_rootfs(struct rsync_data *data);
+int rsync_rootfs_wrapper(void *data);
+
+#endif // __LXC_RSYNC_H