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- /*
- * 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
- *
- * ELF image format
- *
- * A "pure" ELF image is not a bootable image. There are various
- * bootable formats based upon ELF (e.g. Multiboot), which share
- * common ELF-related functionality.
- */
-
- #include <errno.h>
- #include <elf.h>
- #include <gpxe/uaccess.h>
- #include <gpxe/segment.h>
- #include <gpxe/image.h>
- #include <gpxe/elf.h>
-
- typedef Elf32_Ehdr Elf_Ehdr;
- typedef Elf32_Phdr Elf_Phdr;
- typedef Elf32_Off Elf_Off;
-
- /**
- * Load ELF segment into memory
- *
- * @v image ELF file
- * @v phdr ELF program header
- * @ret rc Return status code
- */
- static int elf_load_segment ( struct image *image, Elf_Phdr *phdr ) {
- physaddr_t dest;
- userptr_t buffer;
- int rc;
-
- /* Do nothing for non-PT_LOAD segments */
- if ( phdr->p_type != PT_LOAD )
- return 0;
-
- /* Check segment lies within image */
- if ( ( phdr->p_offset + phdr->p_filesz ) > image->len ) {
- DBG ( "ELF segment outside ELF file\n" );
- return -ENOEXEC;
- }
-
- /* Find start address: use physical address for preference,
- * fall back to virtual address if no physical address
- * supplied.
- */
- dest = phdr->p_paddr;
- if ( ! dest )
- dest = phdr->p_vaddr;
- if ( ! dest ) {
- DBG ( "ELF segment loads to physical address 0\n" );
- return -ENOEXEC;
- }
- buffer = phys_to_user ( dest );
-
- DBG ( "ELF loading segment [%lx,%lx) to [%lx,%lx,%lx)\n",
- phdr->p_offset, ( phdr->p_offset + phdr->p_filesz ),
- phdr->p_paddr, ( phdr->p_paddr + phdr->p_filesz ),
- ( phdr->p_paddr + phdr->p_memsz ) );
-
- /* Verify and prepare segment */
- if ( ( rc = prep_segment ( buffer, phdr->p_filesz,
- phdr->p_memsz ) ) != 0 ) {
- DBG ( "ELF could not prepare segment: %s\n", strerror ( rc ) );
- return rc;
- }
-
- /* Copy image to segment */
- memcpy_user ( buffer, 0, image->data, phdr->p_offset, phdr->p_filesz );
-
- return 0;
- }
-
- /**
- * Load ELF image into memory
- *
- * @v image ELF file
- * @ret rc Return status code
- */
- int elf_load ( struct image *image ) {
- Elf_Ehdr ehdr;
- Elf_Phdr phdr;
- Elf_Off phoff;
- unsigned int phnum;
- int rc;
-
- /* Image type must already have been set by caller */
- assert ( image->type != NULL );
-
- /* Read ELF header */
- copy_from_user ( &ehdr, image->data, 0, sizeof ( ehdr ) );
- if ( memcmp ( &ehdr.e_ident[EI_MAG0], ELFMAG, SELFMAG ) != 0 ) {
- DBG ( "Invalid ELF signature\n" );
- return -ENOEXEC;
- }
-
- /* Read ELF program headers */
- for ( phoff = ehdr.e_phoff , phnum = ehdr.e_phnum ; phnum ;
- phoff += ehdr.e_phentsize, phnum-- ) {
- if ( phoff > image->len ) {
- DBG ( "ELF program header %d outside ELF image\n",
- phnum );
- return -ENOEXEC;
- }
- copy_from_user ( &phdr, image->data, phoff, sizeof ( phdr ) );
- if ( ( rc = elf_load_segment ( image, &phdr ) ) != 0 )
- return rc;
- }
-
- /* Record execution entry point in image private data field */
- image->priv.phys = ehdr.e_entry;
-
- return 0;
- }
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