PATCH (updated): 'lilo -R' functionality

[Keir Fraser]

The following is a slight modification to the patch I submitted a week
or so ago. This will cause GRUB to skip displaying the boot menu if a
one-shot default has been specified (just as lilo does with '-R').

Same caveats as for previous patch:
 * The new 'savedefault' function in the GRUB shell is incomplete.
   Only works if the filesystem containing stage2 file is mounted.
 * Patch is against grub-0.90, but patches directly to 0.91

I hope this goes into CVS in the next round of updates :-)

 -- Keir Fraser



diff -urBP grub-0.90-old/ChangeLog grub-0.90-modified/ChangeLog
--- grub-0.90-old/ChangeLog     Fri Feb 22 11:59:42 2002
+++ grub-0.90-modified/ChangeLog        Fri Feb 22 11:56:21 2002
@@ -1,3 +1,10 @@
+2002-02-22  Keir Fraser  <address@hidden>
+
+       * stage2/shared.h: New flag STAGE2_ONCEONLY_ENTRY causes
+       SAVED_ENTRYNO to be reset to zero on next reboot.
+       * stage2/builtins.c: A new version of 'savedefault' function
+       for the GRUB shell. Provides 'lilo -R' functionality.
+       
 2001-07-07  OKUJI Yoshinori  <address@hidden>
 
        * netboot/compile: New file. This was also missing... How many
diff -urBP grub-0.90-old/stage2/builtins.c grub-0.90-modified/stage2/builtins.c
--- grub-0.90-old/stage2/builtins.c     Fri Feb 22 11:59:57 2002
+++ grub-0.90-modified/stage2/builtins.c        Fri Feb 22 13:48:36 2002
@@ -785,6 +785,17 @@
 default_func (char *arg, int flags)
 {
 #ifndef SUPPORT_DISKLESS
+#ifndef GRUB_UTIL
+  /* Has a forced once-only default been specified? */
+  static int savedefault_helper(int);
+  if ((saved_entryno & STAGE2_ONCEONLY_ENTRY) != 0)
+    {
+      grub_timeout = 0;
+      default_entry = saved_entryno & ~STAGE2_ONCEONLY_ENTRY;
+      savedefault_helper(0);
+      return 0;
+    }
+#endif
   if (grub_strcmp (arg, "saved") == 0)
     {
       default_entry = saved_entryno;
@@ -3074,22 +3085,15 @@
 };
 
 
-/* savedefault */
+
+#if !defined(SUPPORT_DISKLESS) && !defined(GRUB_UTIL)
+/* Write specified default entry number into stage2 file. */
 static int
-savedefault_func (char *arg, int flags)
+savedefault_helper(int new_default)
 {
-#if !defined(SUPPORT_DISKLESS) && !defined(GRUB_UTIL)
   char buffer[512];
   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, &buf_geom))
@@ -3115,10 +3119,10 @@
   entryno_ptr = (int *) (buffer + STAGE2_SAVED_ENTRYNO);
 
   /* Check if the saved entry number differs from current entry number.  */
-  if (*entryno_ptr != current_entryno)
+  if (*entryno_ptr != new_default)
     {
       /* Overwrite the saved entry number.  */
-      *entryno_ptr = current_entryno;
+      *entryno_ptr = new_default;
       
       /* Save the image in the disk.  */
       if (! rawwrite (boot_drive, install_second_sector, buffer))
@@ -3129,6 +3133,117 @@
     }
 
   return 0;
+}
+#endif
+
+#if !defined(SUPPORT_DISKLESS) && defined(GRUB_UTIL)
+/*
+ * Full implementation of new `savedefault' for GRUB shell.
+ * XXX This needs fixing for stage2 files which aren't accessible
+ *     through a mounted filesystem.
+ */
+static int
+savedefault_shell(char *arg, int flags)
+{
+  char *stage2_os_file = "/boot/grub/stage2"; /* Default filename */
+  FILE *fp;
+  char buffer[512];
+  int *entryno_ptr;
+  int new_default = 0;
+
+  while (1)
+    {
+      if (grub_memcmp ("--stage2=", arg, sizeof ("--stage2=") - 1) == 0)
+        {
+          stage2_os_file = arg + sizeof ("--stage2=") - 1;
+          arg = skip_to (0, arg);
+          nul_terminate (stage2_os_file);
+        }
+      else if (grub_memcmp ("--default=", arg, sizeof ("--default=") - 1) == 0)
+        {
+          char *p = arg + sizeof ("--default=") - 1;
+          if (! safe_parse_maxint (&p, &new_default))
+            return 1;
+          arg = skip_to (0, arg);
+        }
+      else if (grub_memcmp ("--once", arg, sizeof ("--once") - 1) == 0)
+        {
+          new_default |= STAGE2_ONCEONLY_ENTRY;
+          arg = skip_to (0, arg);
+        }
+      else
+        break;
+    }
+
+  if (! (fp = fopen(stage2_os_file, "r+")))
+    {
+      errnum = ERR_FILE_NOT_FOUND;
+      return 1;
+    }
+  
+  if (fseek (fp, SECTOR_SIZE, SEEK_SET) != 0)
+    {
+      fclose (fp);
+      errnum = ERR_BAD_VERSION;
+      return 1;
+    }
+  
+  if (fread (buffer, 1, SECTOR_SIZE, fp) != SECTOR_SIZE)
+    {
+      fclose (fp);
+      errnum = ERR_READ;
+      return 1;
+    }
+
+  /* Sanity check.  */
+  if (buffer[STAGE2_STAGE2_ID] != STAGE2_ID_STAGE2
+      || *((short *) (buffer + STAGE2_VER_MAJ_OFFS)) != COMPAT_VERSION)
+    {
+      errnum = ERR_BAD_VERSION;
+      return 1;
+    }
+  
+  entryno_ptr = (int *) (buffer + STAGE2_SAVED_ENTRYNO);
+  *entryno_ptr = new_default;
+
+  if (fseek (fp, SECTOR_SIZE, SEEK_SET) != 0)
+    {
+      fclose (fp);
+      errnum = ERR_BAD_VERSION;
+      return 1;
+    }
+  
+  if (fwrite (buffer, 1, SECTOR_SIZE, fp) != SECTOR_SIZE)
+    {
+      fclose (fp);
+      errnum = ERR_WRITE;
+      return 1;
+    }
+  
+  (void)fflush (fp);
+  fclose (fp);
+  return 0;
+}
+#endif
+
+/* savedefault */
+static int
+savedefault_func (char *arg, int flags)
+{
+#if !defined(SUPPORT_DISKLESS)
+#if !defined(GRUB_UTIL)
+  /* This command is only useful when you boot an entry from the menu
+     interface.  */
+  if (! (flags & BUILTIN_SCRIPT))
+    {
+      errnum = ERR_UNRECOGNIZED;
+      return 1;
+    }
+
+  return savedefault_helper(current_entryno);
+#else /* defined(GRUB_UTIL) */
+  return savedefault_shell(arg, flags);
+#endif
 #else /* ! SUPPORT_DISKLESS && ! GRUB_UTIL */
   errnum = ERR_UNRECOGNIZED;
   return 1;
@@ -3140,8 +3255,14 @@
   "savedefault",
   savedefault_func,
   BUILTIN_CMDLINE,
+#ifdef GRUB_UTIL
+  "savedefault [--stage2=STAGE2_FILE] [--default=DEFAULT] [--once]",
+  "Save DEFAULT as the default boot entry in STAGE2_FILE. If '--once'"
+  " is specified, the default is reset after the next reboot."
+#else
   "savedefault",
   "Save the current entry as the default boot entry."
+#endif
 };
 
 
@@ -4217,6 +4338,15 @@
 static int
 timeout_func (char *arg, int flags)
 {
+  /* One-shot default shenanigans -- don't piss around with the menu! */
+  if (grub_timeout != -1)
+    return 0;
+  if ((saved_entryno & STAGE2_ONCEONLY_ENTRY) != 0)
+    {
+      grub_timeout = 0;
+      return 0;
+    }
+
   if (! safe_parse_maxint (&arg, &grub_timeout))
     return 1;
 
diff -urBP grub-0.90-old/stage2/shared.h grub-0.90-modified/stage2/shared.h
--- grub-0.90-old/stage2/shared.h       Fri Feb 22 11:59:53 2002
+++ grub-0.90-modified/stage2/shared.h  Fri Feb 22 10:51:49 2002
@@ -199,6 +199,8 @@
 #define STAGE2_FORCE_LBA       0x11
 #define STAGE2_VER_STR_OFFS    0x12
 
+#define STAGE2_ONCEONLY_ENTRY   0x10000
+
 /* Stage 2 identifiers */
 #define STAGE2_ID_STAGE2               0
 #define STAGE2_ID_FFS_STAGE1_5         1