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Add code for constructing single-file cpio archives on the fly

This commit is contained in:
Michael Brown 2007-08-01 23:10:30 +01:00
parent 24f32a1945
commit 726e366e8f
3 changed files with 166 additions and 30 deletions
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105
src/arch/i386/image/bzimage.c
View File

@ -35,6 +35,7 @@
#include <gpxe/segment.h>
#include <gpxe/init.h>
#include <gpxe/initrd.h>
#include <gpxe/cpio.h>
struct image_type bzimage_image_type __image_type ( PROBE_NORMAL );
@ -166,6 +167,63 @@ static int bzimage_set_cmdline ( struct image *image,
return 0;
}
/**
* Load initrd
*
* @v image bzImage image
* @v initrd initrd image
* @v address Address at which to load, or UNULL
* @ret len Length of loaded image, rounded up to 4 bytes
*/
static size_t bzimage_load_initrd ( struct image *image,
struct image *initrd,
userptr_t address ) {
char *filename = initrd->cmdline;
struct cpio_header cpio;
size_t offset = 0;
/* Ignore images which aren't initrds */
if ( initrd->type != &initrd_image_type )
return 0;
/* Create cpio header before non-prebuilt images */
if ( filename[0] ) {
size_t name_len = ( strlen ( filename ) + 1 );
DBGC ( image, "bzImage %p inserting initrd %p as %s\n",
image, initrd, filename );
memset ( &cpio, '0', sizeof ( cpio ) );
memcpy ( cpio.c_magic, CPIO_MAGIC, sizeof ( cpio.c_magic ) );
cpio_set_field ( cpio.c_mode, 0100644 );
cpio_set_field ( cpio.c_nlink, 1 );
cpio_set_field ( cpio.c_filesize, initrd->len );
cpio_set_field ( cpio.c_namesize, name_len );
if ( address ) {
copy_to_user ( address, offset, &cpio,
sizeof ( cpio ) );
}
offset += sizeof ( cpio );
if ( address ) {
copy_to_user ( address, offset, filename,
name_len );
}
offset += name_len;
offset = ( ( offset + 0x03 ) & ~0x03 );
}
/* Copy in initrd image body */
if ( address ) {
DBGC ( image, "bzImage %p has initrd %p at [%lx,%lx)\n",
image, initrd, address, ( address + offset ) );
memcpy_user ( address, offset, initrd->data, 0,
initrd->len );
}
offset += initrd->len;
offset = ( ( offset + 0x03 ) & ~0x03 );
return offset;
}
/**
* Load initrds, if any
*
@ -173,21 +231,16 @@ static int bzimage_set_cmdline ( struct image *image,
* @v exec_ctx Execution context
* @ret rc Return status code
*/
static int bzimage_load_initrd ( struct image *image,
struct bzimage_exec_context *exec_ctx ) {
static int bzimage_load_initrds ( struct image *image,
struct bzimage_exec_context *exec_ctx ) {
struct image *initrd;
size_t initrd_len;
size_t total_len = 0;
size_t offset = 0;
physaddr_t start;
physaddr_t address;
int rc;
/* Add up length of all initrd images */
for_each_image ( initrd ) {
if ( initrd->type != &initrd_image_type )
continue;
initrd_len = ( ( initrd->len + 0x0f ) & ~0x0f );
total_len += initrd_len;
total_len += bzimage_load_initrd ( image, initrd, UNULL );
}
/* Give up if no initrd images found */
@ -198,47 +251,39 @@ static int bzimage_load_initrd ( struct image *image,
* starting from the downloaded kernel image itself and
* working downwards until we hit an available region.
*/
for ( start = ( user_to_phys ( image->data, 0 ) & ~0xfffff ) ; ;
start -= 0x100000 ) {
for ( address = ( user_to_phys ( image->data, 0 ) & ~0xfffff ) ; ;
address -= 0x100000 ) {
/* Check that we're not going to overwrite the
* kernel itself. This check isn't totally
* accurate, but errs on the side of caution.
*/
if ( start <= ( BZI_LOAD_HIGH_ADDR + image->len ) ) {
if ( address <= ( BZI_LOAD_HIGH_ADDR + image->len ) ) {
DBGC ( image, "bzImage %p could not find a location "
"for initrd\n", image );
return -ENOBUFS;
}
/* Check that we are within the kernel's range */
if ( ( start + total_len ) > exec_ctx->mem_limit )
if ( ( address + total_len ) > exec_ctx->mem_limit )
continue;
/* Prepare and verify segment */
if ( ( rc = prep_segment ( phys_to_user ( start ), 0,
if ( ( rc = prep_segment ( phys_to_user ( address ), 0,
total_len ) ) != 0 )
continue;
/* Use this address */
break;
}
/* Record initrd location */
exec_ctx->ramdisk_image = address;
exec_ctx->ramdisk_size = total_len;
/* Construct initrd */
DBGC ( image, "bzImage %p constructing initrd at [%lx,%lx)\n",
image, start, ( start + total_len ) );
image, address, ( address + total_len ) );
for_each_image ( initrd ) {
if ( initrd->type != &initrd_image_type )
continue;
initrd_len = ( ( initrd->len + 0x0f ) & ~0x0f );
DBGC ( image, "bzImage %p has initrd %p at [%lx,%lx)\n",
image, initrd, ( start + offset ),
( start + offset + initrd->len ) );
memcpy_user ( phys_to_user ( start ), offset,
initrd->data, 0, initrd->len );
offset += initrd_len;
address += bzimage_load_initrd ( image, initrd,
phys_to_user ( address ) );
}
assert ( offset == total_len );
/* Record initrd location */
exec_ctx->ramdisk_image = start;
exec_ctx->ramdisk_size = total_len;
return 0;
}
@ -281,7 +326,7 @@ static int bzimage_exec ( struct image *image ) {
return rc;
/* Load any initrds */
if ( ( rc = bzimage_load_initrd ( image, &exec_ctx ) ) != 0 )
if ( ( rc = bzimage_load_initrds ( image, &exec_ctx ) ) != 0 )
return rc;
/* Update and store kernel header */

40
src/core/cpio.c Normal file
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@ -0,0 +1,40 @@
/*
* Copyright (C) 2007 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
*
* CPIO archives
*
*/
#include <stdio.h>
#include <string.h>
#include <gpxe/cpio.h>
/**
* Set field within a CPIO header
*
* @v field Field within CPIO header
* @v value Value to set
*/
void cpio_set_field ( char *field, unsigned long value ) {
char buf[9];
snprintf ( buf, sizeof ( buf ), "%08lx", value );
memcpy ( field, buf, 8 );
}

51
src/include/gpxe/cpio.h Normal file
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@ -0,0 +1,51 @@
#ifndef _GPXE_CPIO_H
#define _GPXE_CPIO_H
/** @file
*
* CPIO archives
*
*/
/** A CPIO archive header
*
* All field are hexadecimal ASCII numbers padded with '0' on the
* left to the full width of the field.
*/
struct cpio_header {
/** The string "070701" or "070702" */
char c_magic[6];
/** File inode number */
char c_ino[8];
/** File mode and permissions */
char c_mode[8];
/** File uid */
char c_uid[8];
/** File gid */
char c_gid[8];
/** Number of links */
char c_nlink[8];
/** Modification time */
char c_mtime[8];
/** Size of data field */
char c_filesize[8];
/** Major part of file device number */
char c_maj[8];
/** Minor part of file device number */
char c_min[8];
/** Major part of device node reference */
char c_rmaj[8];
/** Minor part of device node reference */
char c_rmin[8];
/** Length of filename, including final NUL */
char c_namesize[8];
/** Checksum of data field if c_magic is 070702, othersize zero */
char c_chksum[8];
} __attribute__ (( packed ));
/** CPIO magic */
#define CPIO_MAGIC "070701"
extern void cpio_set_field ( char *field, unsigned long value );
#endif /* _GPXE_CPIO_H */