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[prefix] Allow an initrd to be passed to iPXE
Allow an initrd (such as an embedded script) to be passed to iPXE when
loaded as a .lkrn (or .iso) image.  This allows an embedded script to
be varied without recompiling iPXE.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Nov 12, 2011
1 parent 2422647 commit 27fdb95
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Showing 4 changed files with 262 additions and 124 deletions.
123 changes: 0 additions & 123 deletions src/arch/i386/core/cmdline.c

This file was deleted.

249 changes: 249 additions & 0 deletions src/arch/i386/core/runtime.c
@@ -0,0 +1,249 @@
/*
* Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

FILE_LICENCE ( GPL2_OR_LATER );

/** @file
*
* Command line and initrd passed to iPXE at runtime
*
*/

#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/init.h>
#include <ipxe/image.h>
#include <ipxe/script.h>
#include <ipxe/umalloc.h>
#include <realmode.h>

/** Command line physical address
*
* This can be set by the prefix.
*/
uint32_t __bss16 ( cmdline_phys );
#define cmdline_phys __use_data16 ( cmdline_phys )

/** initrd physical address
*
* This can be set by the prefix.
*/
uint32_t __bss16 ( initrd_phys );
#define initrd_phys __use_data16 ( initrd_phys )

/** initrd length
*
* This can be set by the prefix.
*/
uint32_t __bss16 ( initrd_len );
#define initrd_len __use_data16 ( initrd_len )

/** Internal copy of the command line */
static char *cmdline_copy;

/** Free command line image */
static void cmdline_image_free ( struct refcnt *refcnt ) {
struct image *image = container_of ( refcnt, struct image, refcnt );

DBGC ( image, "RUNTIME freeing command line\n" );
free ( cmdline_copy );
}

/** Embedded script representing the command line */
static struct image cmdline_image = {
.refcnt = REF_INIT ( cmdline_image_free ),
.name = "<CMDLINE>",
.type = &script_image_type,
};

/** Colour for debug messages */
#define colour &cmdline_image

/**
* Strip unwanted cruft from command line
*
* @v cmdline Command line
* @v cruft Initial substring of cruft to strip
*/
static void cmdline_strip ( char *cmdline, const char *cruft ) {
char *strip;
char *strip_end;

/* Find unwanted cruft, if present */
if ( ! ( strip = strstr ( cmdline, cruft ) ) )
return;

/* Strip unwanted cruft */
strip_end = strchr ( strip, ' ' );
if ( strip_end ) {
*strip_end = '\0';
DBGC ( colour, "RUNTIME stripping \"%s\"\n", strip );
strcpy ( strip, ( strip_end + 1 ) );
} else {
DBGC ( colour, "RUNTIME stripping \"%s\"\n", strip );
*strip = '\0';
}
}

/**
* Initialise command line
*
* @ret rc Return status code
*/
static int cmdline_init ( void ) {
userptr_t cmdline_user;
char *cmdline;
size_t len;
int rc;

/* Do nothing if no command line was specified */
if ( ! cmdline_phys ) {
DBGC ( colour, "RUNTIME found no command line\n" );
return 0;
}
cmdline_user = phys_to_user ( cmdline_phys );
len = ( strlen_user ( cmdline_user, 0 ) + 1 /* NUL */ );

/* Allocate and copy command line */
cmdline_copy = malloc ( len );
if ( ! cmdline_copy ) {
DBGC ( colour, "RUNTIME could not allocate %zd bytes for "
"command line\n", len );
rc = -ENOMEM;
goto err_alloc_cmdline_copy;
}
cmdline = cmdline_copy;
copy_from_user ( cmdline, cmdline_user, 0, len );
DBGC ( colour, "RUNTIME found command line \"%s\"\n", cmdline );

/* Strip unwanted cruft from the command line */
cmdline_strip ( cmdline, "BOOT_IMAGE=" );
cmdline_strip ( cmdline, "initrd=" );
while ( isspace ( *cmdline ) )
cmdline++;
DBGC ( colour, "RUNTIME using command line \"%s\"\n", cmdline );

/* Prepare and register image */
cmdline_image.data = virt_to_user ( cmdline );
cmdline_image.len = strlen ( cmdline );
if ( cmdline_image.len ) {
if ( ( rc = register_image ( &cmdline_image ) ) != 0 ) {
DBGC ( colour, "RUNTIME could not register command "
"line: %s\n", strerror ( rc ) );
goto err_register_image;
}
}

/* Drop our reference to the image */
image_put ( &cmdline_image );

return 0;

err_register_image:
image_put ( &cmdline_image );
err_alloc_cmdline_copy:
return rc;
}

/**
* Initialise initrd
*
* @ret rc Return status code
*/
static int initrd_init ( void ) {
struct image *image;
int rc;

/* Do nothing if no initrd was specified */
if ( ! initrd_phys ) {
DBGC ( colour, "RUNTIME found no initrd\n" );
return 0;
}
if ( ! initrd_len ) {
DBGC ( colour, "RUNTIME found empty initrd\n" );
return 0;
}
DBGC ( colour, "RUNTIME found initrd at [%x,%x)\n",
initrd_phys, ( initrd_phys + initrd_len ) );

/* Allocate image */
image = alloc_image();
if ( ! image ) {
DBGC ( colour, "RUNTIME could not allocate image for "
"initrd\n" );
goto err_alloc_image;
}
image_set_name ( image, "<INITRD>" );

/* Allocate and copy initrd content */
image->data = umalloc ( initrd_len );
if ( ! image->data ) {
DBGC ( colour, "RUNTIME could not allocate %zd bytes for "
"initrd\n", initrd_len );
goto err_umalloc;
}
image->len = initrd_len;
memcpy_user ( image->data, 0, phys_to_user ( initrd_phys ), 0,
initrd_len );

/* Register image */
if ( ( rc = register_image ( image ) ) != 0 ) {
DBGC ( colour, "RUNTIME could not register initrd: %s\n",
strerror ( rc ) );
goto err_register_image;
}

/* Drop our reference to the image */
image_put ( image );

return 0;

err_register_image:
err_umalloc:
image_put ( image );
err_alloc_image:
return rc;
}

/**
* Initialise command line and initrd
*
*/
static void runtime_init ( void ) {
int rc;

/* Initialise command line */
if ( ( rc = cmdline_init() ) != 0 ) {
/* No way to report failure */
return;
}

/* Initialise initrd */
if ( ( rc = initrd_init() ) != 0 ) {
/* No way to report failure */
return;
}
}

/** Command line and initrd initialisation function */
struct init_fn runtime_init_fn __init_fn ( INIT_NORMAL ) = {
.initialise = runtime_init,
};
1 change: 1 addition & 0 deletions src/arch/i386/include/bits/errfile.h
Expand Up @@ -15,6 +15,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
#define ERRFILE_biosint ( ERRFILE_ARCH | ERRFILE_CORE | 0x00040000 )
#define ERRFILE_int13 ( ERRFILE_ARCH | ERRFILE_CORE | 0x00050000 )
#define ERRFILE_pxeparent ( ERRFILE_ARCH | ERRFILE_CORE | 0x00060000 )
#define ERRFILE_runtime ( ERRFILE_ARCH | ERRFILE_CORE | 0x00070000 )

#define ERRFILE_bootsector ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00000000 )
#define ERRFILE_bzimage ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00010000 )
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