add support for saving a default entry number in your disk.

ChangeLog

@@ -1,3 +1,33 @@
+2000-09-06  OKUJI Yoshinori  <okuji@gnu.org>
+
+	Add support for "boot previously booted entry by default", based
+	on the patch by Mike Meyer <mwm@mired.org>, but I've modified
+	his patch thoroughly.
+	
+	* grub/asmstub.c (saved_entryno): New variable. This is a dummy.
+	* stage1/stage1.h (COMPAT_VERSION_MINOR): Incremented.
+	* stage2/asm.S (saved_entryno): New variable.
+	(codestart) [!SUPPORT_DISKLESS]: Set INSTALL_SECOND_SECTOR to
+	%ebp. %ebp is set in start.S.
+	(install_second_sector): New variable.
+	* stage2/builtins.c (current_entryno): New variable.
+	(default_func) [!SUPPORT_DISKLESS]: If ARG is "saved", set
+	DEFAULT_ENTRY to SAVED_ENTRYNO.
+	(savedefault_func): New function.
+	(builtin_savedefault): New variable.
+	(builtin_table): Added a pointer to BUILTIN_SAVEDEFAULT.
+	* stage2/shared.h (STAGE2_SAVED_ENTRYNO): New macro.
+	(STAGE2_STAGE2_ID): Changed to 0x10.
+	(STAGE2_FORCE_LBA): Chaged to 0x11.
+	(STAGE2_VER_STR_OFFS): Changed to 0x12.
+	(install_second_sector): Declared.
+	(saved_entryno): Likewise.
+	(current_entryno): Likewise.
+	* stage2/stage2.c (run_menu): Set CURRENT_ENTRYNO to FIRST_ENTRY
+	+ ENTRYNO, right before calling run_script.
+	* stage2/start.S (start): Save the sector number of the second
+	sector in %ebp.
+	
 2000-09-05  OKUJI Yoshinori  <okuji@gnu.org>
 
 	* stage1/stage1.S (lba_mode) [!NO_BUGGY_BIOS_IN_THE_WORLD]:

NEWS

@@ -32,6 +32,9 @@ New in 0.5.96 - XXXX-XX-XX:
 * Also only for developers: you can specify an optional argument to the
   option `--hold' for the grub shell. The argument means how many
   seconds the grub shell should wait until diving into the main routine.
+* New command, "savedefault". Now you can save current entry number to
+  your disk with this command and then you can set the default boot
+  entry to it by the command "default saved".
 
 New in 0.5.95 - 2000-06-27:
 * NetBSD ELF kernel support is added. You have to specify the new option

THANKS

@@ -35,6 +35,7 @@ M. Meiarashi <mes@st.rim.or.jp>
 Mark Lundeberg <aa026@pgfn.bc.ca>
 Matthias Kretschmer <m.kretschmer@bsdger.org>
 Michael Hohmuth <hohmuth@innocent.com>
+Mike Meyer <mwm@mired.org>
 Miles Bader <miles@gnu.org>
 Neal H Walfield <neal@walfield.org>
 OKUJI Yoshinori <okuji@kuicr.kyoto-u.ac.jp>

grub/asmstub.c

@@ -67,6 +67,7 @@ int grub_stage2 (void);
 
 unsigned long install_partition = 0x20000;
 unsigned long boot_drive = 0;
+int saved_entryno = 0;
 char version_string[] = VERSION;
 char config_file[128] = "/boot/grub/menu.lst"; /* FIXME: arbitrary */
 unsigned long linux_text_len = 0;

stage1/stage1.h

@@ -23,7 +23,7 @@
 
 /* Define the version numbers here, so that Stage 1 can know them.  */
 #define COMPAT_VERSION_MAJOR	3
-#define COMPAT_VERSION_MINOR	1
+#define COMPAT_VERSION_MINOR	2
 #define COMPAT_VERSION		((COMPAT_VERSION_MINOR << 8) \
 					| COMPAT_VERSION_MAJOR)
 

stage2/asm.S

@@ -88,6 +88,8 @@ ENTRY(main)
 
 VARIABLE(install_partition)
 	.long	0xFFFFFF
+VARIABLE(saved_entryno)
+	.long	0
 VARIABLE(stage2_id)
 	.byte	STAGE2_ID
 VARIABLE(force_lba)
@@ -118,6 +120,14 @@ codestart:
 	movw	%ax, %ss
 	movw	%ax, %es
 
+#ifndef SUPPORT_DISKLESS
+	/*
+	 * Save the sector number of the second sector (i.e. this sector)
+	 * in INSTALL_SECOND_SECTOR. See also "stage2/start.S".
+	 */
+	ADDR32	movl	%ebp, EXT_C(install_second_sector)
+#endif
+	
 	/* set up the real mode/BIOS stack */
 	movl	$STACKOFF, %ebp
 	movl	%ebp, %esp
@@ -2103,6 +2113,9 @@ VARIABLE(boot_drive)
 	.long	0
 #endif
 
+VARIABLE(install_second_sector)
+	.long	0
+	
 	/* an address can only be long-jumped to if it is in memory, this
 	   is used by multiple routines */
 offset:

stage2/builtins.c

@@ -55,6 +55,8 @@ int debug = 0;
 int default_entry = 0;
 /* The fallback entry.  */
 int fallback_entry = -1;
+/* The number of current entry.  */
+int current_entryno;
 /* The address for Multiboot command-line buffer.  */
 static char *mb_cmdline;
 /* The password.  */
@@ -713,6 +715,14 @@ static struct builtin builtin_debug =
 static int
 default_func (char *arg, int flags)
 {
+#ifndef SUPPORT_DISKLESS
+  if (grub_strcmp (arg, "saved") == 0)
+    {
+      default_entry = saved_entryno;
+      return 0;
+    }
+#endif /* SUPPORT_DISKLESS */
+  
   if (! safe_parse_maxint (&arg, &default_entry))
     return 1;
 
@@ -725,9 +735,9 @@ static struct builtin builtin_default =
   default_func,
   BUILTIN_MENU,
 #if 0
-  "default NUM",
+  "default [NUM | `saved']",
   "Set the default entry to entry number NUM (if not specified, it is"
-  " 0, the first entry)."
+  " 0, the first entry) or the entry number saved by savedefault."
 #endif
 };
 
@@ -2644,6 +2654,75 @@ static struct builtin builtin_rootnoverify =
   " derived from attempting the mount will NOT work correctly."
 };
 
+
+/* savedefault */
+static int
+savedefault_func (char *arg, int flags)
+{
+#if !defined(SUPPORT_DISKLESS) && !defined(GRUB_UTIL)
+  struct geometry geom;
+  int *entryno_ptr;
+  
+  /* This command is only useful when you boot an entry from the menu
+     interface.  */
+  if (! (flags & BUILTIN_SCRIPT))
+    {
+      errnum = ERR_UNRECOGNIZED;
+      return 1;
+    }
+  
+  /* Get the geometry of the boot drive (i.e. the disk which contains
+     this stage2).  */
+  if (get_diskinfo (boot_drive, &geom))
+    {
+      errnum = ERR_NO_DISK;
+      return 1;
+    }
+
+  /* Load the second sector of this stage2.  */
+  if (biosdisk (BIOSDISK_READ, boot_drive, &geom,
+		install_second_sector, 1, SCRATCHSEG))
+    {
+      errnum = ERR_READ;
+      return 1;
+    }
+
+  entryno_ptr = (int *) ((char *) SCRATCHADDR + STAGE2_SAVED_ENTRYNO);
+
+  /* Check if the saved entry number differs from current entry number.  */
+  if (*entryno_ptr != current_entryno)
+    {
+      /* Overwrite the saved entry number.  */
+      *entryno_ptr = current_entryno;
+      
+      /* Save the image in the disk.  */
+      if (biosdisk (BIOSDISK_WRITE, boot_drive, &geom,
+		    install_second_sector, 1, SCRATCHSEG))
+	{
+	  errnum = ERR_WRITE;
+	  return 1;
+	}
+      
+      /* Clear the cache.  */
+      buf_track = -1;
+    }
+
+  return 0;
+#else /* ! SUPPORT_DISKLESS && ! GRUB_UTIL */
+  errnum = ERR_UNRECOGNIZED;
+  return 1;
+#endif /* ! SUPPORT_DISKLESS && ! GRUB_UTIL */
+}
+
+static struct builtin builtin_savedefault =
+{
+  "savedefault",
+  savedefault_func,
+  BUILTIN_CMDLINE,
+  "savedefault",
+  "Save the current entry as the default boot entry."
+};
+
 
 /* serial */
 static int
@@ -3665,6 +3744,7 @@ struct builtin *builtin_table[] =
   &builtin_reboot,
   &builtin_root,
   &builtin_rootnoverify,
+  &builtin_savedefault,
   &builtin_serial,
   &builtin_setkey,
   &builtin_setup,

stage2/shared.h

@@ -192,9 +192,10 @@ extern char *grub_scratch_mem;
 
 #define STAGE2_VER_MAJ_OFFS	0x6
 #define STAGE2_INSTALLPART	0x8
-#define STAGE2_STAGE2_ID	0xc
-#define STAGE2_FORCE_LBA	0xd
-#define STAGE2_VER_STR_OFFS	0xe
+#define STAGE2_SAVED_ENTRYNO	0xc
+#define STAGE2_STAGE2_ID	0x10
+#define STAGE2_FORCE_LBA	0x11
+#define STAGE2_VER_STR_OFFS	0x12
 
 /* Stage 2 identifiers */
 #define STAGE2_ID_STAGE2		0
@@ -464,8 +465,10 @@ typedef enum
 
 extern unsigned long install_partition;
 extern unsigned long boot_drive;
+extern unsigned long install_second_sector;
 extern unsigned long boot_part_addr;
 extern unsigned long boot_part_offset;
+extern int saved_entryno;
 extern unsigned char force_lba;
 extern char version_string[];
 extern char config_file[];
@@ -497,6 +500,7 @@ extern void assign_device_name (int drive, const char *device);
 /* GUI interface variables. */
 extern int fallback_entry;
 extern int default_entry;
+extern int current_entryno;
 extern char *password;
 extern int auth;
 extern char commands[];

stage2/stage2.c

@@ -681,9 +681,7 @@ restart:
 	}
     }
 
-  /*
-   *  Attempt to boot an entry.
-   */
+  /* Attempt to boot an entry.  */
  boot_entry:
   while (1)
     {
@@ -698,6 +696,9 @@ restart:
       if (! cur_entry)
 	cur_entry = get_entry (config_entries, first_entry + entryno, 1);
 
+      /* Set CURRENT_ENTRYNO for the command "savedefault".  */
+      current_entryno = first_entry + entryno;
+      
       if (run_script (cur_entry, heap))
 	{
 	  if (fallback_entry < 0)

stage2/start.S

@@ -74,6 +74,8 @@ _start:
 	/* this sets up for the first run through "bootloop" */
 	movw	$ABS(firstlist - BOOTSEC_LISTSIZE), %di
 
+	/* save the sector number of the second sector in %ebp */
+	movl	(%di), %ebp
 
         /* this is the loop for reading the secondary boot-loader in */
 bootloop: