2N/A/* elf.c - load ELF files */
2N/A/*
2N/A * GRUB -- GRand Unified Bootloader
2N/A * Copyright (C) 2003,2004,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
2N/A *
2N/A * GRUB is free software: you can redistribute it and/or modify
2N/A * it under the terms of the GNU General Public License as published by
2N/A * the Free Software Foundation, either version 3 of the License, or
2N/A * (at your option) any later version.
2N/A *
2N/A * GRUB is distributed in the hope that it will be useful,
2N/A * but WITHOUT ANY WARRANTY; without even the implied warranty of
2N/A * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
2N/A * GNU General Public License for more details.
2N/A *
2N/A * You should have received a copy of the GNU General Public License
2N/A * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
2N/A */
2N/A
2N/A#include <grub/err.h>
2N/A#include <grub/elf.h>
2N/A#include <grub/elfload.h>
2N/A#include <grub/file.h>
2N/A#include <grub/misc.h>
2N/A#include <grub/mm.h>
2N/A#include <grub/dl.h>
2N/A
2N/AGRUB_MOD_LICENSE ("GPLv3+");
2N/A
2N/A/* Check if EHDR is a valid ELF header. */
2N/Astatic grub_err_t
2N/Agrub_elf_check_header (grub_elf_t elf)
2N/A{
2N/A Elf32_Ehdr *e = &elf->ehdr.ehdr32;
2N/A
2N/A if (e->e_ident[EI_MAG0] != ELFMAG0
2N/A || e->e_ident[EI_MAG1] != ELFMAG1
2N/A || e->e_ident[EI_MAG2] != ELFMAG2
2N/A || e->e_ident[EI_MAG3] != ELFMAG3
2N/A || e->e_ident[EI_VERSION] != EV_CURRENT
2N/A || e->e_version != EV_CURRENT)
2N/A return grub_error (GRUB_ERR_BAD_OS, "invalid arch independent ELF magic");
2N/A
2N/A return GRUB_ERR_NONE;
2N/A}
2N/A
2N/Agrub_err_t
2N/Agrub_elf_close (grub_elf_t elf)
2N/A{
2N/A grub_file_t file = elf->file;
2N/A
2N/A grub_free (elf->phdrs);
2N/A grub_free (elf);
2N/A
2N/A if (file)
2N/A grub_file_close (file);
2N/A
2N/A return grub_errno;
2N/A}
2N/A
2N/Agrub_elf_t
2N/Agrub_elf_file (grub_file_t file)
2N/A{
2N/A grub_elf_t elf;
2N/A
2N/A elf = grub_zalloc (sizeof (*elf));
2N/A if (! elf)
2N/A return 0;
2N/A
2N/A elf->file = file;
2N/A
2N/A if (grub_file_seek (elf->file, 0) == (grub_off_t) -1)
2N/A goto fail;
2N/A
2N/A if (grub_file_read (elf->file, &elf->ehdr, sizeof (elf->ehdr))
2N/A != sizeof (elf->ehdr))
2N/A {
2N/A grub_error_push ();
2N/A grub_error (GRUB_ERR_READ_ERROR, "cannot read ELF header");
2N/A goto fail;
2N/A }
2N/A
2N/A if (grub_elf_check_header (elf))
2N/A goto fail;
2N/A
2N/A return elf;
2N/A
2N/Afail:
2N/A grub_free (elf->phdrs);
2N/A grub_free (elf);
2N/A return 0;
2N/A}
2N/A
2N/Agrub_elf_t
2N/Agrub_elf_open (const char *name)
2N/A{
2N/A grub_file_t file;
2N/A grub_elf_t elf;
2N/A
2N/A file = grub_file_open (name);
2N/A if (! file)
2N/A return 0;
2N/A
2N/A elf = grub_elf_file (file);
2N/A if (! elf)
2N/A grub_file_close (file);
2N/A
2N/A return elf;
2N/A}
2N/A
2N/A
2N/A/* 32-bit */
2N/A
2N/Aint
2N/Agrub_elf_is_elf32 (grub_elf_t elf)
2N/A{
2N/A return elf->ehdr.ehdr32.e_ident[EI_CLASS] == ELFCLASS32;
2N/A}
2N/A
2N/Astatic grub_err_t
2N/Agrub_elf32_load_phdrs (grub_elf_t elf)
2N/A{
2N/A grub_ssize_t phdrs_size;
2N/A
2N/A phdrs_size = elf->ehdr.ehdr32.e_phnum * elf->ehdr.ehdr32.e_phentsize;
2N/A
2N/A grub_dprintf ("elf", "Loading program headers at 0x%llx, size 0x%lx.\n",
2N/A (unsigned long long) elf->ehdr.ehdr32.e_phoff,
2N/A (unsigned long) phdrs_size);
2N/A
2N/A elf->phdrs = grub_malloc (phdrs_size);
2N/A if (! elf->phdrs)
2N/A return grub_errno;
2N/A
2N/A if ((grub_file_seek (elf->file, elf->ehdr.ehdr32.e_phoff) == (grub_off_t) -1)
2N/A || (grub_file_read (elf->file, elf->phdrs, phdrs_size) != phdrs_size))
2N/A {
2N/A grub_error_push ();
2N/A return grub_error (GRUB_ERR_READ_ERROR, "cannot read program headers");
2N/A }
2N/A
2N/A return GRUB_ERR_NONE;
2N/A}
2N/A
2N/Agrub_err_t
2N/Agrub_elf32_phdr_iterate (grub_elf_t elf,
2N/A int NESTED_FUNC_ATTR (*hook) (grub_elf_t, Elf32_Phdr *, void *),
2N/A void *hook_arg)
2N/A{
2N/A Elf32_Phdr *phdrs;
2N/A unsigned int i;
2N/A
2N/A if (! elf->phdrs)
2N/A if (grub_elf32_load_phdrs (elf))
2N/A return grub_errno;
2N/A phdrs = elf->phdrs;
2N/A
2N/A for (i = 0; i < elf->ehdr.ehdr32.e_phnum; i++)
2N/A {
2N/A Elf32_Phdr *phdr = phdrs + i;
2N/A grub_dprintf ("elf",
2N/A "Segment %u: type 0x%x paddr 0x%lx memsz 0x%lx "
2N/A "filesz %lx\n",
2N/A i, phdr->p_type,
2N/A (unsigned long) phdr->p_paddr,
2N/A (unsigned long) phdr->p_memsz,
2N/A (unsigned long) phdr->p_filesz);
2N/A if (hook (elf, phdr, hook_arg))
2N/A break;
2N/A }
2N/A
2N/A return grub_errno;
2N/A}
2N/A
2N/A/* Calculate the amount of memory spanned by the segments. */
2N/Agrub_size_t
2N/Agrub_elf32_size (grub_elf_t elf, Elf32_Addr *base, grub_uint32_t *max_align)
2N/A{
2N/A Elf32_Addr segments_start = (Elf32_Addr) -1;
2N/A Elf32_Addr segments_end = 0;
2N/A int nr_phdrs = 0;
2N/A grub_uint32_t curr_align = 1;
2N/A
2N/A /* Run through the program headers to calculate the total memory size we
2N/A * should claim. */
2N/A auto int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf, Elf32_Phdr *phdr, void *_arg);
2N/A int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf __attribute__ ((unused)),
2N/A Elf32_Phdr *phdr,
2N/A void *_arg __attribute__ ((unused)))
2N/A {
2N/A /* Only consider loadable segments. */
2N/A if (phdr->p_type != PT_LOAD)
2N/A return 0;
2N/A nr_phdrs++;
2N/A if (phdr->p_paddr < segments_start)
2N/A segments_start = phdr->p_paddr;
2N/A if (phdr->p_paddr + phdr->p_memsz > segments_end)
2N/A segments_end = phdr->p_paddr + phdr->p_memsz;
2N/A if (curr_align < phdr->p_align)
2N/A curr_align = phdr->p_align;
2N/A return 0;
2N/A }
2N/A
2N/A grub_elf32_phdr_iterate (elf, calcsize, 0);
2N/A
2N/A if (base)
2N/A *base = 0;
2N/A
2N/A if (nr_phdrs == 0)
2N/A {
2N/A grub_error (GRUB_ERR_BAD_OS, "no program headers present");
2N/A return 0;
2N/A }
2N/A
2N/A if (segments_end < segments_start)
2N/A {
2N/A /* Very bad addresses. */
2N/A grub_error (GRUB_ERR_BAD_OS, "bad program header load addresses");
2N/A return 0;
2N/A }
2N/A
2N/A if (base)
2N/A *base = segments_start;
2N/A if (max_align)
2N/A *max_align = curr_align;
2N/A return segments_end - segments_start;
2N/A}
2N/A
2N/A/* Load every loadable segment into memory specified by `_load_hook'. */
2N/Agrub_err_t
2N/Agrub_elf32_load (grub_elf_t _elf, grub_elf32_load_hook_t _load_hook,
2N/A grub_addr_t *base, grub_size_t *size)
2N/A{
2N/A grub_addr_t load_base = (grub_addr_t) -1ULL;
2N/A grub_size_t load_size = 0;
2N/A grub_err_t err;
2N/A
2N/A auto int NESTED_FUNC_ATTR grub_elf32_load_segment (grub_elf_t elf, Elf32_Phdr *phdr, void *hook);
2N/A int NESTED_FUNC_ATTR grub_elf32_load_segment (grub_elf_t elf, Elf32_Phdr *phdr, void *hook)
2N/A {
2N/A grub_elf32_load_hook_t load_hook = (grub_elf32_load_hook_t) hook;
2N/A grub_addr_t load_addr;
2N/A int do_load = 1;
2N/A
2N/A load_addr = phdr->p_paddr;
2N/A if (load_hook && load_hook (phdr, &load_addr, &do_load))
2N/A return 1;
2N/A
2N/A if (! do_load)
2N/A return 0;
2N/A
2N/A if (load_addr < load_base)
2N/A load_base = load_addr;
2N/A
2N/A grub_dprintf ("elf", "Loading segment at 0x%llx, size 0x%llx\n",
2N/A (unsigned long long) load_addr,
2N/A (unsigned long long) phdr->p_memsz);
2N/A
2N/A if (grub_file_seek (elf->file, phdr->p_offset) == (grub_off_t) -1)
2N/A {
2N/A grub_error_push ();
2N/A return grub_error (GRUB_ERR_BAD_OS,
2N/A "invalid offset in program header");
2N/A }
2N/A
2N/A if (phdr->p_filesz)
2N/A {
2N/A grub_ssize_t read;
2N/A read = grub_file_read (elf->file, (void *) load_addr, phdr->p_filesz);
2N/A if (read != (grub_ssize_t) phdr->p_filesz)
2N/A {
2N/A /* XXX How can we free memory from `load_hook'? */
2N/A grub_error_push ();
2N/A return grub_error (GRUB_ERR_BAD_OS,
2N/A "couldn't read segment from file: "
2N/A "wanted 0x%lx bytes; read 0x%lx bytes",
2N/A phdr->p_filesz, read);
2N/A }
2N/A }
2N/A
2N/A if (phdr->p_filesz < phdr->p_memsz)
2N/A grub_memset ((void *) (long) (load_addr + phdr->p_filesz),
2N/A 0, phdr->p_memsz - phdr->p_filesz);
2N/A
2N/A load_size += phdr->p_memsz;
2N/A
2N/A return 0;
2N/A }
2N/A
2N/A err = grub_elf32_phdr_iterate (_elf, grub_elf32_load_segment, _load_hook);
2N/A
2N/A if (base)
2N/A *base = load_base;
2N/A if (size)
2N/A *size = load_size;
2N/A
2N/A return err;
2N/A}
2N/A
2N/A
2N/A/* 64-bit */
2N/A
2N/Aint
2N/Agrub_elf_is_elf64 (grub_elf_t elf)
2N/A{
2N/A return elf->ehdr.ehdr64.e_ident[EI_CLASS] == ELFCLASS64;
2N/A}
2N/A
2N/Astatic grub_err_t
2N/Agrub_elf64_load_phdrs (grub_elf_t elf)
2N/A{
2N/A grub_ssize_t phdrs_size;
2N/A
2N/A phdrs_size = elf->ehdr.ehdr64.e_phnum * elf->ehdr.ehdr64.e_phentsize;
2N/A
2N/A grub_dprintf ("elf", "Loading program headers at 0x%llx, size 0x%lx.\n",
2N/A (unsigned long long) elf->ehdr.ehdr64.e_phoff,
2N/A (unsigned long) phdrs_size);
2N/A
2N/A elf->phdrs = grub_malloc (phdrs_size);
2N/A if (! elf->phdrs)
2N/A return grub_errno;
2N/A
2N/A if ((grub_file_seek (elf->file, elf->ehdr.ehdr64.e_phoff) == (grub_off_t) -1)
2N/A || (grub_file_read (elf->file, elf->phdrs, phdrs_size) != phdrs_size))
2N/A {
2N/A grub_error_push ();
2N/A return grub_error (GRUB_ERR_READ_ERROR, "cannot read program headers");
2N/A }
2N/A
2N/A return GRUB_ERR_NONE;
2N/A}
2N/A
2N/Agrub_err_t
2N/Agrub_elf64_phdr_iterate (grub_elf_t elf,
2N/A int NESTED_FUNC_ATTR (*hook) (grub_elf_t, Elf64_Phdr *, void *),
2N/A void *hook_arg)
2N/A{
2N/A Elf64_Phdr *phdrs;
2N/A unsigned int i;
2N/A
2N/A if (! elf->phdrs)
2N/A if (grub_elf64_load_phdrs (elf))
2N/A return grub_errno;
2N/A phdrs = elf->phdrs;
2N/A
2N/A for (i = 0; i < elf->ehdr.ehdr64.e_phnum; i++)
2N/A {
2N/A Elf64_Phdr *phdr = phdrs + i;
2N/A grub_dprintf ("elf",
2N/A "Segment %u: type 0x%x paddr 0x%lx memsz 0x%lx "
2N/A "filesz %lx\n",
2N/A i, phdr->p_type,
2N/A (unsigned long) phdr->p_paddr,
2N/A (unsigned long) phdr->p_memsz,
2N/A (unsigned long) phdr->p_filesz);
2N/A if (hook (elf, phdr, hook_arg))
2N/A break;
2N/A }
2N/A
2N/A return grub_errno;
2N/A}
2N/A
2N/A/* Calculate the amount of memory spanned by the segments. */
2N/Agrub_size_t
2N/Agrub_elf64_size (grub_elf_t elf, Elf64_Addr *base, grub_uint64_t *max_align)
2N/A{
2N/A Elf64_Addr segments_start = (Elf64_Addr) -1;
2N/A Elf64_Addr segments_end = 0;
2N/A int nr_phdrs = 0;
2N/A grub_uint64_t curr_align = 1;
2N/A
2N/A /* Run through the program headers to calculate the total memory size we
2N/A * should claim. */
2N/A auto int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf, Elf64_Phdr *phdr, void *_arg);
2N/A int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf __attribute__ ((unused)),
2N/A Elf64_Phdr *phdr,
2N/A void *_arg __attribute__ ((unused)))
2N/A {
2N/A /* Only consider loadable segments. */
2N/A if (phdr->p_type != PT_LOAD)
2N/A return 0;
2N/A nr_phdrs++;
2N/A if (phdr->p_paddr < segments_start)
2N/A segments_start = phdr->p_paddr;
2N/A if (phdr->p_paddr + phdr->p_memsz > segments_end)
2N/A segments_end = phdr->p_paddr + phdr->p_memsz;
2N/A if (curr_align < phdr->p_align)
2N/A curr_align = phdr->p_align;
2N/A return 0;
2N/A }
2N/A
2N/A grub_elf64_phdr_iterate (elf, calcsize, 0);
2N/A
2N/A if (base)
2N/A *base = 0;
2N/A
2N/A if (nr_phdrs == 0)
2N/A {
2N/A grub_error (GRUB_ERR_BAD_OS, "no program headers present");
2N/A return 0;
2N/A }
2N/A
2N/A if (segments_end < segments_start)
2N/A {
2N/A /* Very bad addresses. */
2N/A grub_error (GRUB_ERR_BAD_OS, "bad program header load addresses");
2N/A return 0;
2N/A }
2N/A
2N/A if (base)
2N/A *base = segments_start;
2N/A if (max_align)
2N/A *max_align = curr_align;
2N/A return segments_end - segments_start;
2N/A}
2N/A
2N/A/* Load every loadable segment into memory specified by `_load_hook'. */
2N/Agrub_err_t
2N/Agrub_elf64_load (grub_elf_t _elf, grub_elf64_load_hook_t _load_hook,
2N/A grub_addr_t *base, grub_size_t *size)
2N/A{
2N/A grub_addr_t load_base = (grub_addr_t) -1ULL;
2N/A grub_size_t load_size = 0;
2N/A grub_err_t err;
2N/A
2N/A auto int NESTED_FUNC_ATTR grub_elf64_load_segment (grub_elf_t elf, Elf64_Phdr *phdr,
2N/A void *hook);
2N/A int NESTED_FUNC_ATTR grub_elf64_load_segment (grub_elf_t elf, Elf64_Phdr *phdr, void *hook)
2N/A {
2N/A grub_elf64_load_hook_t load_hook = (grub_elf64_load_hook_t) hook;
2N/A grub_addr_t load_addr;
2N/A int do_load = 1;
2N/A
2N/A load_addr = phdr->p_paddr;
2N/A if (load_hook && load_hook (phdr, &load_addr, &do_load))
2N/A return 1;
2N/A
2N/A if (! do_load)
2N/A return 0;
2N/A
2N/A if (load_addr < load_base)
2N/A load_base = load_addr;
2N/A
2N/A grub_dprintf ("elf", "Loading segment at 0x%llx, size 0x%llx\n",
2N/A (unsigned long long) load_addr,
2N/A (unsigned long long) phdr->p_memsz);
2N/A
2N/A if (grub_file_seek (elf->file, phdr->p_offset) == (grub_off_t) -1)
2N/A {
2N/A grub_error_push ();
2N/A return grub_error (GRUB_ERR_BAD_OS,
2N/A "invalid offset in program header");
2N/A }
2N/A
2N/A if (phdr->p_filesz)
2N/A {
2N/A grub_ssize_t read;
2N/A read = grub_file_read (elf->file, (void *) load_addr, phdr->p_filesz);
2N/A if (read != (grub_ssize_t) phdr->p_filesz)
2N/A {
2N/A /* XXX How can we free memory from `load_hook'? */
2N/A grub_error_push ();
2N/A return grub_error (GRUB_ERR_BAD_OS,
2N/A "couldn't read segment from file: "
2N/A "wanted 0x%lx bytes; read 0x%lx bytes",
2N/A phdr->p_filesz, read);
2N/A }
2N/A }
2N/A
2N/A if (phdr->p_filesz < phdr->p_memsz)
2N/A grub_memset ((void *) (long) (load_addr + phdr->p_filesz),
2N/A 0, phdr->p_memsz - phdr->p_filesz);
2N/A
2N/A load_size += phdr->p_memsz;
2N/A
2N/A return 0;
2N/A }
2N/A
2N/A err = grub_elf64_phdr_iterate (_elf, grub_elf64_load_segment, _load_hook);
2N/A
2N/A if (base)
2N/A *base = load_base;
2N/A if (size)
2N/A *size = load_size;
2N/A
2N/A return err;
2N/A}