From 98fb5cb9a46c0c4ff854649bc2a4a594bd4b4f0e Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Mon, 18 Jun 2007 15:47:26 +0200
Subject: applied save-default-entry-on-mbr.diff

---
 stage2/builtins.c |    2 +
 stage2/disk_io.c  |   54 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 stage2/shared.h   |    5 ++++
 stage2/stage2.c   |    3 ++
 4 files changed, 64 insertions(+), 0 deletions(-)

diff --git a/stage2/builtins.c b/stage2/builtins.c
index 535c713..7fe6cc6 100644
--- a/stage2/builtins.c
+++ b/stage2/builtins.c
@@ -3343,6 +3343,8 @@ savedefault_func (char *arg, int flags)
       /* Clear the cache.  */
       buf_track = -1;
     }
+  else
+    put_new_entryno_to_mbr(tmp_drive, entryno);
 
  fail:
   saved_drive = tmp_drive;
diff --git a/stage2/disk_io.c b/stage2/disk_io.c
index b9bc526..5b88e8c 100644
--- a/stage2/disk_io.c
+++ b/stage2/disk_io.c
@@ -1788,3 +1788,57 @@ grub_close (void)
   if (fsys_table[fsys_type].close_func != 0)
     (*(fsys_table[fsys_type].close_func)) ();
 }
+
+#ifndef STAGE1_5
+int
+read_entryno_from_mbr(int drive, char *sector)
+{
+    /* drive must be a hard disk and stage1_5 must be right after the MBR */
+    if (!(drive & 0x80))
+	return 0;
+    if (!rawread(drive, 2, 0, SECTOR_SIZE, sector))
+	return 0;
+    /* sanity checks */
+    if (sector[STAGE2_VER_MAJ_OFFS]   != COMPAT_VERSION_MAJOR ||
+	sector[STAGE2_VER_MAJ_OFFS+1] != COMPAT_VERSION_MINOR ||
+	*(unsigned *)&sector[STAGE2_INSTALLPART] != 0xFFFFFF ||
+	grub_memcmp(&sector[STAGE2_VER_STR_OFFS], version_string,
+		    sizeof(VERSION))) {
+#if 0
+	printf("read: sec=%d %d %d %s=%s(%d)\n",
+	       sector[STAGE2_VER_MAJ_OFFS], sector[STAGE2_VER_MAJ_OFFS+1],
+	       sector[STAGE2_INSTALLPART], &sector[STAGE2_VER_STR_OFFS],
+	       version_string, sizeof(VERSION));
+#endif
+	return 0;
+    }
+    return 1;
+}
+
+/* Get saved_entryno from the MBR */
+void
+get_saved_entryno_from_mbr(int drive)
+{
+    char sector[SECTOR_SIZE];
+
+    errnum = ERR_NONE;
+    if (!read_entryno_from_mbr(drive, sector))
+	return 0;
+    /* get it from the saved_entryno place */
+    saved_entryno = *(unsigned*)&sector[STAGE2_SAVED_ENTRYNO];
+}
+
+/* Put entryno into the MBR. Returns 1 if done, otherwise 0 (error...) */
+int
+put_new_entryno_to_mbr(int drive, unsigned entryno)
+{
+    char sector[SECTOR_SIZE];
+
+    errnum = ERR_NONE;
+    if (!read_entryno_from_mbr(saved_drive, sector))
+	return 0;
+    *(unsigned *)&sector[STAGE2_SAVED_ENTRYNO] = entryno;
+    rawwrite (drive, 2, sector);
+    return !errnum;
+}
+#endif /* STAGE1_5 */
diff --git a/stage2/shared.h b/stage2/shared.h
index 77eef11..f01d6ee 100644
--- a/stage2/shared.h
+++ b/stage2/shared.h
@@ -956,6 +956,11 @@ int grub_seek (int offset);
 /* Close a file.  */
 void grub_close (void);
 
+#ifndef STAGE1_5
+void get_saved_entryno_from_mbr(int drive);
+int put_new_entryno_to_mbr(int drive, unsigned entryno);
+#endif
+
 /* List the contents of the directory that was opened with GRUB_OPEN,
    printing all completions. */
 int dir (char *dirname);
diff --git a/stage2/stage2.c b/stage2/stage2.c
index 96e18cd..a93a630 100644
--- a/stage2/stage2.c
+++ b/stage2/stage2.c
@@ -896,6 +896,9 @@ cmain (void)
 
 	      grub_close ();
 	    }
+	  else
+	    get_saved_entryno_from_mbr(saved_drive);
+
 	  errnum = ERR_NONE;
 	  
 	  do
-- 
1.4.4.3