--- /dev/null
+/*
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @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 <ipxe/uaccess.h>
+#include <ipxe/segment.h>
+#include <ipxe/image.h>
+#include <ipxe/elf.h>
+
+typedef Elf32_Ehdr Elf_Ehdr;
+typedef Elf32_Phdr Elf_Phdr;
+typedef Elf32_Off Elf_Off;
+#define ELFCLASS ELFCLASS32
+
+/**
+ * Load ELF segment into memory
+ *
+ * @v image ELF file
+ * @v phdr ELF program header
+ * @v ehdr ELF executable header
+ * @ret entry Entry point, if found
+ * @ret max Maximum used address
+ * @ret rc Return status code
+ */
+static int elf_load_segment ( struct image *image, Elf_Phdr *phdr,
+ Elf_Ehdr *ehdr, physaddr_t *entry,
+ physaddr_t *max ) {
+ physaddr_t dest;
+ physaddr_t end;
+ userptr_t buffer;
+ unsigned long e_offset;
+ 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 ) {
+ DBGC ( image, "ELF %p segment outside image\n", image );
+ 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 ) {
+ DBGC ( image, "ELF %p segment loads to physical address 0\n",
+ image );
+ return -ENOEXEC;
+ }
+ buffer = phys_to_user ( dest );
+ end = ( dest + phdr->p_memsz );
+
+ DBGC ( image, "ELF %p loading segment [%x,%x) to [%x,%x,%x)\n", image,
+ 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 ) {
+ DBGC ( image, "ELF %p could not prepare segment: %s\n",
+ image, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Update maximum used address, if applicable */
+ if ( end > *max )
+ *max = end;
+
+ /* Copy image to segment */
+ memcpy_user ( buffer, 0, image->data, phdr->p_offset, phdr->p_filesz );
+
+ /* Set execution address, if it lies within this segment */
+ if ( ( e_offset = ( ehdr->e_entry - dest ) ) < phdr->p_filesz ) {
+ *entry = ehdr->e_entry;
+ DBGC ( image, "ELF %p found physical entry point at %lx\n",
+ image, *entry );
+ } else if ( ( e_offset = ( ehdr->e_entry - phdr->p_vaddr ) )
+ < phdr->p_filesz ) {
+ if ( ! *entry ) {
+ *entry = ( dest + e_offset );
+ DBGC ( image, "ELF %p found virtual entry point at %lx"
+ " (virt %lx)\n", image, *entry,
+ ( ( unsigned long ) ehdr->e_entry ) );
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * Load ELF image into memory
+ *
+ * @v image ELF file
+ * @ret entry Entry point
+ * @ret max Maximum used address
+ * @ret rc Return status code
+ */
+int elf_load ( struct image *image, physaddr_t *entry, physaddr_t *max ) {
+ static const uint8_t e_ident[] = {
+ [EI_MAG0] = ELFMAG0,
+ [EI_MAG1] = ELFMAG1,
+ [EI_MAG2] = ELFMAG2,
+ [EI_MAG3] = ELFMAG3,
+ [EI_CLASS] = ELFCLASS,
+ };
+ Elf_Ehdr ehdr;
+ Elf_Phdr phdr;
+ Elf_Off phoff;
+ unsigned int phnum;
+ int rc;
+
+ /* Read ELF header */
+ copy_from_user ( &ehdr, image->data, 0, sizeof ( ehdr ) );
+ if ( memcmp ( &ehdr.e_ident[EI_MAG0], e_ident,
+ sizeof ( e_ident ) ) != 0 ) {
+ DBGC ( image, "ELF %p has invalid signature\n", image );
+ return -ENOEXEC;
+ }
+
+ /* Initialise maximum used address */
+ *max = 0;
+
+ /* Invalidate entry point */
+ *entry = 0;
+
+ /* Read ELF program headers */
+ for ( phoff = ehdr.e_phoff , phnum = ehdr.e_phnum ; phnum ;
+ phoff += ehdr.e_phentsize, phnum-- ) {
+ if ( phoff > image->len ) {
+ DBGC ( image, "ELF %p program header %d outside "
+ "image\n", image, phnum );
+ return -ENOEXEC;
+ }
+ copy_from_user ( &phdr, image->data, phoff, sizeof ( phdr ) );
+ if ( ( rc = elf_load_segment ( image, &phdr, &ehdr,
+ entry, max ) ) != 0 ) {
+ return rc;
+ }
+ }
+
+ /* Check for a valid execution address */
+ if ( ! *entry ) {
+ DBGC ( image, "ELF %p entry point %lx outside image\n",
+ image, ( ( unsigned long ) ehdr.e_entry ) );
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff