From: Zhu Yi <chu...@octavia.sh.intel.com>
Make grub-setup backup the old boot sectors into a file
(bootsectors.bak) before overwriting it. The backup image starts from
the MBR to the end of core.img position (including embed regions).
This makes it possible for a user to later restore it with dd or
other methods.
Signed-off-by: Zhu Yi <yi....@intel.com>
---
util/i386/pc/grub-setup.c | 33 +++++++++++++++++++++++++++++++++
1 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/util/i386/pc/grub-setup.c b/util/i386/pc/grub-setup.c
index c536be0..b045e23 100644
--- a/util/i386/pc/grub-setup.c
+++ b/util/i386/pc/grub-setup.c
@@ -53,6 +53,7 @@ static const grub_gpt_part_type_t
grub_gpt_partition_type_bios_boot = GRUB_GPT_P
#define DEFAULT_BOOT_FILE "boot.img"
#define DEFAULT_CORE_FILE "core.img"
+#define DEFAULT_BACKUP_FILE "bootsectors.bak"
/* This is the blocklist used in the diskboot image. */
struct boot_blocklist
@@ -396,6 +397,33 @@ setup (const char *dir,
block->len = 0;
block->segment = 0;
+ int grub_disk_backup(grub_disk_t disk, grub_size_t size, const char *path)
+ {
+ char *tmp_buf;
+
+ grub_util_info ("opening the backup file `%s'", path);
+ fp = fopen (path, "wb");
+ if (! fp)
+ return -1;
+
+ tmp_buf = xmalloc (size);
+ if (grub_disk_read (disk, 0, 0, size, tmp_buf) != GRUB_ERR_NONE) {
+ fclose (fp);
+ return -1;
+ }
+
+ grub_util_write_image (tmp_buf, size, fp);
+
+ fclose (fp);
+ return 0;
+ }
+
+ /* Backup old boot sectors */
+ if (grub_disk_backup (dest_dev->disk,
+ GRUB_DISK_SECTOR_SIZE * embed_region.start + core_size,
+ grub_util_get_path (dir, DEFAULT_BACKUP_FILE)))
+ grub_util_error ("failed to backup previous boot sectors");
+
/* Write the core image onto the disk. */
if (grub_disk_write (dest_dev->disk, embed_region.start, 0, core_size,
core_img))
grub_util_error ("%s", grub_errmsg);
@@ -548,6 +576,11 @@ unable_to_embed:
grub_util_write_image (core_img, GRUB_DISK_SECTOR_SIZE * 2, fp);
fclose (fp);
+ /* Backup MBR only */
+ if (grub_disk_backup (dest_dev->disk, GRUB_DISK_SECTOR_SIZE,
+ grub_util_get_path (dir, DEFAULT_BACKUP_FILE)))
+ grub_util_error ("failed to backup previous boot sectors");
+
/* Write the boot image onto the disk. */
if (grub_disk_write (dest_dev->disk, 0, 0, GRUB_DISK_SECTOR_SIZE, boot_img))
grub_util_error ("%s", grub_errmsg);
--
1.5.3.6
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