On Wed, Jun 13, 2007 at 01:37:15AM +0800, Bean wrote:
> On Tue, Jun 12, 2007 at 03:54:12PM +0200, Robert Millan wrote:
> >
> > Is there any reason why grub_prefix is in boot.img rather than core.img ?
> >
> > This brings problems when the following conditions are met:
> >
> > - core.img is loaded directly without boot.img (via GRUB Legacy)
> > - grub is not in /boot/grub (typicaly, when /boot is a separate partition)
> >
> > If grub_prefix is moved to core.img, then grub-mkimage could be modified to
> > override prefix, supporting this setup.
> >
> > Is this a good way to fix it?
> >
>
> I believe grub_prefix IS in core.img. It begins at 0x21C from the beginning
> of core.img. You may also want to modify the variable grub_install_dos_part
> at 0x214, for example, if booting from the first partition, set it to 0.
>
> The above variables are defined in kern/i386/pc/startup.S.
Ah, somehow I got the impression that startup.S was part of boot.img :-)
Here's a patch to add a --prefix option for the pc and efi version of
grub-mkimage, that moves initialisation of grub_prefix from kernel image
to grub-mkimage, possibly overriding it.
I tested it and is known to work, but does this look right? Can someone
comment?
--
Robert Millan
My spam trap is [EMAIL PROTECTED] Note: this address is only intended
for spam harvesters. Writing to it will get you added to my black list.
diff -ur grub2-1.95+20070611.old/kern/i386/efi/startup.S grub2-1.95+20070611/kern/i386/efi/startup.S
--- grub2-1.95+20070611.old/kern/i386/efi/startup.S 2006-04-18 08:18:15.000000000 +0200
+++ grub2-1.95+20070611/kern/i386/efi/startup.S 2007-06-13 15:51:18.000000000 +0200
@@ -45,7 +45,7 @@
. = EXT_C(start) + 0x8
VARIABLE(grub_prefix)
- .string "/boot/grub"
+ /* to be filled by grub-mkimage */
/*
* Leave some breathing room for the prefix.
diff -ur grub2-1.95+20070611.old/kern/i386/pc/startup.S grub2-1.95+20070611/kern/i386/pc/startup.S
--- grub2-1.95+20070611.old/kern/i386/pc/startup.S 2006-05-14 23:16:19.000000000 +0200
+++ grub2-1.95+20070611/kern/i386/pc/startup.S 2007-06-13 15:23:06.000000000 +0200
@@ -96,7 +96,7 @@
VARIABLE(grub_install_bsd_part)
.long 0xFFFFFFFF
VARIABLE(grub_prefix)
- .string "/boot/grub"
+ /* to be filled by grub-mkimage */
/*
* Leave some breathing room for the prefix.
diff -ur grub2-1.95+20070611.old/util/i386/efi/grub-mkimage.c grub2-1.95+20070611/util/i386/efi/grub-mkimage.c
--- grub2-1.95+20070611.old/util/i386/efi/grub-mkimage.c 2006-05-08 21:29:10.000000000 +0200
+++ grub2-1.95+20070611/util/i386/efi/grub-mkimage.c 2007-06-13 16:07:40.000000000 +0200
@@ -48,7 +48,7 @@
/* Read the whole kernel image. Return the pointer to a read image,
and store the size in bytes in *SIZE. */
static char *
-read_kernel_module (const char *dir, size_t *size)
+read_kernel_module (const char *dir, char *prefix, size_t *size)
{
char *kernel_image;
char *kernel_path;
@@ -58,6 +58,11 @@
kernel_image = grub_util_read_image (kernel_path);
free (kernel_path);
+ // FIXME: can we avoid hardcoding offset and size of grub_prefix here?
+ if (strlen (prefix) > 0x47)
+ grub_util_error ("prefix too long");
+ strcpy (kernel_image + 0x3c, prefix);
+
return kernel_image;
}
@@ -838,7 +843,7 @@
/* Convert an ELF relocatable object into an EFI Application (PE32). */
void
-convert_elf (const char *dir, FILE *out, char *mods[])
+convert_elf (const char *dir, char *prefix, FILE *out, char *mods[])
{
char *kernel_image;
size_t kernel_size;
@@ -855,7 +860,7 @@
Elf32_Addr end_address;
/* Get the kernel image and check the format. */
- kernel_image = read_kernel_module (dir, &kernel_size);
+ kernel_image = read_kernel_module (dir, prefix, &kernel_size);
e = (Elf32_Ehdr *) kernel_image;
if (! check_elf_header (e, kernel_size))
grub_util_error ("invalid ELF header");
@@ -912,6 +917,7 @@
static struct option options[] =
{
{"directory", required_argument, 0, 'd'},
+ {"prefix", required_argument, 0, 'p'},
{"output", required_argument, 0, 'o'},
{"help", no_argument, 0, 'h'},
{"version", no_argument, 0, 'V'},
@@ -931,13 +937,14 @@
Make a bootable image of GRUB.\n\
\n\
-d, --directory=DIR use images and modules under DIR [default=%s]\n\
+-p, --prefix=DIR set grub_prefix directory [default=%s]\n\
-o, --output=FILE output a generated image to FILE\n\
-h, --help display this message and exit\n\
-V, --version print version information and exit\n\
-v, --verbose print verbose messages\n\
\n\
Report bugs to <%s>.\n\
-", GRUB_LIBDIR, PACKAGE_BUGREPORT);
+", GRUB_LIBDIR, DEFAULT_DIRECTORY, PACKAGE_BUGREPORT);
exit (status);
}
@@ -948,12 +955,13 @@
FILE *fp;
char *output = NULL;
char *dir = NULL;
+ char *prefix = NULL;
progname = "grub-mkimage";
while (1)
{
- int c = getopt_long (argc, argv, "d:o:hVv", options, 0);
+ int c = getopt_long (argc, argv, "d:p:o:hVv", options, 0);
if (c == -1)
break;
@@ -972,6 +980,11 @@
free (output);
output = xstrdup (optarg);
break;
+ case 'p':
+ if (prefix)
+ free (prefix);
+ prefix = xstrdup (optarg);
+ break;
case 'V':
printf ("grub-mkimage (%s) %s\n", PACKAGE_NAME, PACKAGE_VERSION);
return 0;
@@ -991,7 +1004,7 @@
if (! fp)
grub_util_error ("cannot open %s", output);
- convert_elf (dir ? : GRUB_LIBDIR, fp, argv + optind);
+ convert_elf (dir ? : GRUB_LIBDIR, prefix ? : DEFAULT_DIRECTORY, fp, argv + optind);
fclose (fp);
diff -ur grub2-1.95+20070611.old/util/i386/pc/grub-mkimage.c grub2-1.95+20070611/util/i386/pc/grub-mkimage.c
--- grub2-1.95+20070611.old/util/i386/pc/grub-mkimage.c 2006-11-25 04:21:29.000000000 +0100
+++ grub2-1.95+20070611/util/i386/pc/grub-mkimage.c 2007-06-13 16:07:05.000000000 +0200
@@ -76,7 +76,7 @@
}
static void
-generate_image (const char *dir, FILE *out, char *mods[])
+generate_image (const char *dir, char *prefix, FILE *out, char *mods[])
{
grub_addr_t module_addr = 0;
char *kernel_img, *boot_img, *core_img;
@@ -101,6 +101,10 @@
kernel_img = xmalloc (kernel_size + total_module_size);
grub_util_load_image (kernel_path, kernel_img);
+ // FIXME: can we avoid hardcoding offset and size of grub_prefix here?
+ if (strlen (prefix) > 0x33)
+ grub_util_error ("prefix too long");
+ strcpy (kernel_img + 0x1c, prefix);
/* Fill in the grub_module_info structure. */
modinfo = (struct grub_module_info *) (kernel_img + kernel_size);
@@ -182,6 +186,7 @@
static struct option options[] =
{
{"directory", required_argument, 0, 'd'},
+ {"prefix", required_argument, 0, 'p'},
{"output", required_argument, 0, 'o'},
{"help", no_argument, 0, 'h'},
{"version", no_argument, 0, 'V'},
@@ -201,13 +206,14 @@
Make a bootable image of GRUB.\n\
\n\
-d, --directory=DIR use images and modules under DIR [default=%s]\n\
+ -p, --prefix=DIR set grub_prefix directory [default=%s]\n\
-o, --output=FILE output a generated image to FILE [default=stdout]\n\
-h, --help display this message and exit\n\
-V, --version print version information and exit\n\
-v, --verbose print verbose messages\n\
\n\
Report bugs to <%s>.\n\
-", GRUB_LIBDIR, PACKAGE_BUGREPORT);
+", GRUB_LIBDIR, DEFAULT_DIRECTORY, PACKAGE_BUGREPORT);
exit (status);
}
@@ -215,15 +221,16 @@
int
main (int argc, char *argv[])
{
- char *output = 0;
- char *dir = 0;
+ char *output = NULL;
+ char *dir = NULL;
+ char *prefix = NULL;
FILE *fp = stdout;
progname = "grub-mkimage";
while (1)
{
- int c = getopt_long (argc, argv, "d:o:hVv", options, 0);
+ int c = getopt_long (argc, argv, "d:p:o:hVv", options, 0);
if (c == -1)
break;
@@ -248,6 +255,13 @@
usage (0);
break;
+ case 'p':
+ if (prefix)
+ free (prefix);
+
+ prefix = xstrdup (optarg);
+ break;
+
case 'V':
printf ("grub-mkimage (%s) %s\n", PACKAGE_NAME, PACKAGE_VERSION);
return 0;
@@ -269,7 +283,7 @@
grub_util_error ("cannot open %s", output);
}
- generate_image (dir ? : GRUB_LIBDIR, fp, argv + optind);
+ generate_image (dir ? : GRUB_LIBDIR, prefix ? : DEFAULT_DIRECTORY, fp, argv + optind);
fclose (fp);
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