mount: Basic mount points dumping

Dumping is straightforward -- just copy all the mount_info
fields into the new image file. Dump everything but fstype,
this one will come in a separate patch.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/image.h

@@ -289,6 +289,17 @@ struct ipc_sem_entry {
 	u8	pad[6];
 } __packed;
 
+struct mnt_entry {
+	u32	mnt_id;
+	u32	root_dev;
+	u32	root_dentry_len;
+	u32	parent_mnt_id;
+	u32	mountpoint_path_len;
+	u32	flags;
+	u32	source_len;
+	u32	options_len;
+} __packed;
+
 #define VMA_AREA_NONE		(0 <<  0)
 #define VMA_AREA_REGULAR	(1 <<  0)	/* Dumpable area */
 #define VMA_AREA_STACK		(1 <<  1)

mount.c

@@ -7,12 +7,15 @@
 #include <errno.h>
 #include <sys/stat.h>
 #include <string.h>
+#include <stdlib.h>
 
+#include "crtools.h"
 #include "types.h"
 #include "util.h"
 #include "log.h"
 #include "mount.h"
 #include "proc_parse.h"
+#include "image.h"
 
 static struct mount_info *mntinfo;
 
@@ -38,13 +41,111 @@ int collect_mount_info(void)
 	return 0;
 }
 
+static int dump_one_mountpoint(struct mount_info *pm, int fd)
+{
+	struct mnt_entry me;
+
+	pr_info("\t%d: %x:%s @ %s\n", pm->mnt_id, pm->s_dev,
+			pm->root, pm->mountpoint);
+
+	me.mnt_id = pm->mnt_id;
+	me.root_dev = pm->s_dev;
+	me.root_dentry_len = strlen(pm->root);
+	me.parent_mnt_id = pm->parent_mnt_id;
+	me.mountpoint_path_len = strlen(pm->mountpoint);
+
+	me.flags = pm->flags;
+	me.source_len = strlen(pm->source);
+	me.options_len = strlen(pm->options);
+
+	if (write_img(fd, &me))
+		return -1;
+	if (write_img_buf(fd, pm->root, me.root_dentry_len))
+		return -1;
+	if (write_img_buf(fd, pm->mountpoint, me.mountpoint_path_len))
+		return -1;
+	if (write_img_buf(fd, pm->source, me.source_len))
+		return -1;
+	if (write_img_buf(fd, pm->options, me.options_len))
+		return -1;
+
+	return 0;
+}
+
 int dump_mnt_ns(int ns_pid, struct cr_fdset *fdset)
 {
+	struct mount_info *pm;
+	int img_fd;
+
+	pm = parse_mountinfo(ns_pid);
+	if (!pm) {
+		pr_err("Can't parse %d's mountinfo\n", ns_pid);
+		return -1;
+	}
+
+	pr_info("Dumping mountpoints\n");
+
+	img_fd = fdset_fd(fdset, CR_FD_MOUNTPOINTS);
+	do {
+		struct mount_info *n = pm->next;
+
+		if (dump_one_mountpoint(pm, img_fd))
 			return -1;
+
+		xfree(pm);
+		pm = n;
+	} while (pm);
+
+	return 0;
 }
 
 void show_mountpoints(int fd, struct cr_options *o)
 {
+	struct mnt_entry me;
+	char buf[PATH_MAX];
+
 	pr_img_head(CR_FD_MOUNTPOINTS);
+
+	while (1) {
+		int ret;
+
+		ret = read_img_eof(fd, &me);
+		if (ret <= 0)
+			break;
+
+		pr_msg("%d:%d ", me.mnt_id, me.parent_mnt_id);
+
+		ret = read_img_buf(fd, buf, me.root_dentry_len);
+		if (ret < 0)
+			break;
+
+		buf[me.root_dentry_len] = '\0';
+		pr_msg("%d:%d %s ", kdev_major(me.root_dev),
+				kdev_minor(me.root_dev), buf);
+
+		ret = read_img_buf(fd, buf, me.mountpoint_path_len);
+		if (ret < 0)
+			break;
+
+		buf[me.mountpoint_path_len] = '\0';
+		pr_msg("@ %s ", buf);
+
+		pr_msg("flags %08x ", me.flags);
+
+		ret = read_img_buf(fd, buf, me.source_len);
+		if (ret < 0)
+			break;
+
+		buf[me.source_len] = '\0';
+		pr_msg("dev %s ", buf);
+
+		ret = read_img_buf(fd, buf, me.options_len);
+		if (ret < 0)
+			break;
+
+		buf[me.options_len] = '\0';
+		pr_msg("options %s\n", buf);
+	}
+
 	pr_img_tail(CR_FD_MOUNTPOINTS);
 }