480 lines
12 KiB
C
480 lines
12 KiB
C
/* elf.c - load ELF files */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2003,2004,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/err.h>
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#include <grub/elf.h>
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#include <grub/elfload.h>
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#include <grub/file.h>
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#include <grub/gzio.h>
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#include <grub/misc.h>
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#include <grub/mm.h>
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/* Check if EHDR is a valid ELF header. */
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static grub_err_t
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grub_elf_check_header (grub_elf_t elf)
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{
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Elf32_Ehdr *e = &elf->ehdr.ehdr32;
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if (e->e_ident[EI_MAG0] != ELFMAG0
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|| e->e_ident[EI_MAG1] != ELFMAG1
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|| e->e_ident[EI_MAG2] != ELFMAG2
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|| e->e_ident[EI_MAG3] != ELFMAG3
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|| e->e_ident[EI_VERSION] != EV_CURRENT
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|| e->e_version != EV_CURRENT)
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return grub_error (GRUB_ERR_BAD_OS, "invalid arch independent ELF magic");
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return GRUB_ERR_NONE;
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}
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grub_err_t
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grub_elf_close (grub_elf_t elf)
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{
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grub_file_t file = elf->file;
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grub_free (elf->phdrs);
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grub_free (elf);
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if (file)
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grub_file_close (file);
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return grub_errno;
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}
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grub_elf_t
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grub_elf_file (grub_file_t file)
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{
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grub_elf_t elf;
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elf = grub_zalloc (sizeof (*elf));
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if (! elf)
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return 0;
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elf->file = file;
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if (grub_file_seek (elf->file, 0) == (grub_off_t) -1)
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goto fail;
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if (grub_file_read (elf->file, &elf->ehdr, sizeof (elf->ehdr))
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!= sizeof (elf->ehdr))
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{
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grub_error_push ();
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grub_error (GRUB_ERR_READ_ERROR, "cannot read ELF header");
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goto fail;
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}
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if (grub_elf_check_header (elf))
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goto fail;
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return elf;
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fail:
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grub_free (elf->phdrs);
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grub_free (elf);
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return 0;
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}
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grub_elf_t
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grub_elf_open (const char *name)
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{
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grub_file_t file;
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grub_elf_t elf;
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file = grub_gzfile_open (name, 1);
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if (! file)
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return 0;
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elf = grub_elf_file (file);
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if (! elf)
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grub_file_close (file);
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return elf;
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}
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/* 32-bit */
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int
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grub_elf_is_elf32 (grub_elf_t elf)
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{
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return elf->ehdr.ehdr32.e_ident[EI_CLASS] == ELFCLASS32;
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}
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static grub_err_t
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grub_elf32_load_phdrs (grub_elf_t elf)
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{
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grub_ssize_t phdrs_size;
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phdrs_size = elf->ehdr.ehdr32.e_phnum * elf->ehdr.ehdr32.e_phentsize;
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grub_dprintf ("elf", "Loading program headers at 0x%llx, size 0x%lx.\n",
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(unsigned long long) elf->ehdr.ehdr32.e_phoff,
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(unsigned long) phdrs_size);
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elf->phdrs = grub_malloc (phdrs_size);
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if (! elf->phdrs)
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return grub_errno;
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if ((grub_file_seek (elf->file, elf->ehdr.ehdr32.e_phoff) == (grub_off_t) -1)
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|| (grub_file_read (elf->file, elf->phdrs, phdrs_size) != phdrs_size))
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{
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grub_error_push ();
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return grub_error (GRUB_ERR_READ_ERROR, "cannot read program headers");
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}
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return GRUB_ERR_NONE;
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}
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grub_err_t
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grub_elf32_phdr_iterate (grub_elf_t elf,
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int NESTED_FUNC_ATTR (*hook) (grub_elf_t, Elf32_Phdr *, void *),
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void *hook_arg)
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{
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Elf32_Phdr *phdrs;
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unsigned int i;
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if (! elf->phdrs)
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if (grub_elf32_load_phdrs (elf))
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return grub_errno;
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phdrs = elf->phdrs;
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for (i = 0; i < elf->ehdr.ehdr32.e_phnum; i++)
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{
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Elf32_Phdr *phdr = phdrs + i;
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grub_dprintf ("elf",
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"Segment %u: type 0x%x paddr 0x%lx memsz 0x%lx "
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"filesz %lx\n",
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i, phdr->p_type,
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(unsigned long) phdr->p_paddr,
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(unsigned long) phdr->p_memsz,
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(unsigned long) phdr->p_filesz);
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if (hook (elf, phdr, hook_arg))
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break;
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}
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return grub_errno;
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}
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/* Calculate the amount of memory spanned by the segments. */
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grub_size_t
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grub_elf32_size (grub_elf_t elf, Elf32_Addr *base)
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{
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Elf32_Addr segments_start = (Elf32_Addr) -1;
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Elf32_Addr segments_end = 0;
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int nr_phdrs = 0;
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/* Run through the program headers to calculate the total memory size we
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* should claim. */
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auto int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf, Elf32_Phdr *phdr, void *_arg);
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int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf __attribute__ ((unused)),
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Elf32_Phdr *phdr,
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void *_arg __attribute__ ((unused)))
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{
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/* Only consider loadable segments. */
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if (phdr->p_type != PT_LOAD)
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return 0;
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nr_phdrs++;
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if (phdr->p_paddr < segments_start)
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segments_start = phdr->p_paddr;
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if (phdr->p_paddr + phdr->p_memsz > segments_end)
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segments_end = phdr->p_paddr + phdr->p_memsz;
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return 0;
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}
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grub_elf32_phdr_iterate (elf, calcsize, 0);
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if (base)
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*base = 0;
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if (nr_phdrs == 0)
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{
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grub_error (GRUB_ERR_BAD_OS, "no program headers present");
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return 0;
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}
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if (segments_end < segments_start)
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{
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/* Very bad addresses. */
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grub_error (GRUB_ERR_BAD_OS, "bad program header load addresses");
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return 0;
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}
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if (base)
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*base = segments_start;
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return segments_end - segments_start;
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}
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/* Load every loadable segment into memory specified by `_load_hook'. */
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grub_err_t
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grub_elf32_load (grub_elf_t _elf, grub_elf32_load_hook_t _load_hook,
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grub_addr_t *base, grub_size_t *size)
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{
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grub_addr_t load_base = (grub_addr_t) -1ULL;
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grub_size_t load_size = 0;
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grub_err_t err;
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auto int NESTED_FUNC_ATTR grub_elf32_load_segment (grub_elf_t elf, Elf32_Phdr *phdr, void *hook);
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int NESTED_FUNC_ATTR grub_elf32_load_segment (grub_elf_t elf, Elf32_Phdr *phdr, void *hook)
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{
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grub_elf32_load_hook_t load_hook = (grub_elf32_load_hook_t) hook;
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grub_addr_t load_addr;
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int do_load = 1;
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load_addr = phdr->p_paddr;
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if (load_hook && load_hook (phdr, &load_addr, &do_load))
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return 1;
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if (! do_load)
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return 0;
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if (load_addr < load_base)
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load_base = load_addr;
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grub_dprintf ("elf", "Loading segment at 0x%llx, size 0x%llx\n",
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(unsigned long long) load_addr,
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(unsigned long long) phdr->p_memsz);
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if (grub_file_seek (elf->file, phdr->p_offset) == (grub_off_t) -1)
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{
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grub_error_push ();
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return grub_error (GRUB_ERR_BAD_OS,
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"invalid offset in program header");
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}
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if (phdr->p_filesz)
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{
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grub_ssize_t read;
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read = grub_file_read (elf->file, (void *) load_addr, phdr->p_filesz);
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if (read != (grub_ssize_t) phdr->p_filesz)
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{
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/* XXX How can we free memory from `load_hook'? */
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grub_error_push ();
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return grub_error (GRUB_ERR_BAD_OS,
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"couldn't read segment from file: "
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"wanted 0x%lx bytes; read 0x%lx bytes",
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phdr->p_filesz, read);
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}
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}
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if (phdr->p_filesz < phdr->p_memsz)
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grub_memset ((void *) (long) (load_addr + phdr->p_filesz),
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0, phdr->p_memsz - phdr->p_filesz);
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load_size += phdr->p_memsz;
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return 0;
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}
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err = grub_elf32_phdr_iterate (_elf, grub_elf32_load_segment, _load_hook);
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if (base)
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*base = load_base;
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if (size)
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*size = load_size;
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return err;
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}
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/* 64-bit */
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int
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grub_elf_is_elf64 (grub_elf_t elf)
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{
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return elf->ehdr.ehdr64.e_ident[EI_CLASS] == ELFCLASS64;
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}
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static grub_err_t
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grub_elf64_load_phdrs (grub_elf_t elf)
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{
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grub_ssize_t phdrs_size;
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phdrs_size = elf->ehdr.ehdr64.e_phnum * elf->ehdr.ehdr64.e_phentsize;
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grub_dprintf ("elf", "Loading program headers at 0x%llx, size 0x%lx.\n",
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(unsigned long long) elf->ehdr.ehdr64.e_phoff,
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(unsigned long) phdrs_size);
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elf->phdrs = grub_malloc (phdrs_size);
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if (! elf->phdrs)
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return grub_errno;
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if ((grub_file_seek (elf->file, elf->ehdr.ehdr64.e_phoff) == (grub_off_t) -1)
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|| (grub_file_read (elf->file, elf->phdrs, phdrs_size) != phdrs_size))
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{
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grub_error_push ();
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return grub_error (GRUB_ERR_READ_ERROR, "cannot read program headers");
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}
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return GRUB_ERR_NONE;
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}
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grub_err_t
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grub_elf64_phdr_iterate (grub_elf_t elf,
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int NESTED_FUNC_ATTR (*hook) (grub_elf_t, Elf64_Phdr *, void *),
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void *hook_arg)
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{
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Elf64_Phdr *phdrs;
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unsigned int i;
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if (! elf->phdrs)
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if (grub_elf64_load_phdrs (elf))
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return grub_errno;
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phdrs = elf->phdrs;
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for (i = 0; i < elf->ehdr.ehdr64.e_phnum; i++)
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{
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Elf64_Phdr *phdr = phdrs + i;
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grub_dprintf ("elf",
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"Segment %u: type 0x%x paddr 0x%lx memsz 0x%lx "
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"filesz %lx\n",
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i, phdr->p_type,
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(unsigned long) phdr->p_paddr,
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(unsigned long) phdr->p_memsz,
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(unsigned long) phdr->p_filesz);
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if (hook (elf, phdr, hook_arg))
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break;
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}
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return grub_errno;
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}
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/* Calculate the amount of memory spanned by the segments. */
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grub_size_t
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grub_elf64_size (grub_elf_t elf, Elf64_Addr *base)
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{
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Elf64_Addr segments_start = (Elf64_Addr) -1;
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Elf64_Addr segments_end = 0;
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int nr_phdrs = 0;
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/* Run through the program headers to calculate the total memory size we
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* should claim. */
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auto int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf, Elf64_Phdr *phdr, void *_arg);
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int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf __attribute__ ((unused)),
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Elf64_Phdr *phdr,
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void *_arg __attribute__ ((unused)))
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{
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/* Only consider loadable segments. */
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if (phdr->p_type != PT_LOAD)
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return 0;
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nr_phdrs++;
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if (phdr->p_paddr < segments_start)
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segments_start = phdr->p_paddr;
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if (phdr->p_paddr + phdr->p_memsz > segments_end)
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segments_end = phdr->p_paddr + phdr->p_memsz;
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return 0;
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}
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grub_elf64_phdr_iterate (elf, calcsize, 0);
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if (base)
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*base = 0;
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if (nr_phdrs == 0)
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{
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grub_error (GRUB_ERR_BAD_OS, "no program headers present");
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return 0;
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}
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if (segments_end < segments_start)
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{
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/* Very bad addresses. */
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grub_error (GRUB_ERR_BAD_OS, "bad program header load addresses");
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return 0;
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}
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if (base)
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*base = segments_start;
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return segments_end - segments_start;
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}
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/* Load every loadable segment into memory specified by `_load_hook'. */
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grub_err_t
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grub_elf64_load (grub_elf_t _elf, grub_elf64_load_hook_t _load_hook,
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grub_addr_t *base, grub_size_t *size)
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{
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grub_addr_t load_base = (grub_addr_t) -1ULL;
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grub_size_t load_size = 0;
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grub_err_t err;
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auto int NESTED_FUNC_ATTR grub_elf64_load_segment (grub_elf_t elf, Elf64_Phdr *phdr,
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void *hook);
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int NESTED_FUNC_ATTR grub_elf64_load_segment (grub_elf_t elf, Elf64_Phdr *phdr, void *hook)
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{
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grub_elf64_load_hook_t load_hook = (grub_elf64_load_hook_t) hook;
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grub_addr_t load_addr;
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int do_load = 1;
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load_addr = phdr->p_paddr;
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if (load_hook && load_hook (phdr, &load_addr, &do_load))
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return 1;
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if (! do_load)
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return 0;
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if (load_addr < load_base)
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load_base = load_addr;
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grub_dprintf ("elf", "Loading segment at 0x%llx, size 0x%llx\n",
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(unsigned long long) load_addr,
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(unsigned long long) phdr->p_memsz);
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if (grub_file_seek (elf->file, phdr->p_offset) == (grub_off_t) -1)
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{
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grub_error_push ();
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return grub_error (GRUB_ERR_BAD_OS,
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"invalid offset in program header");
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}
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if (phdr->p_filesz)
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{
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grub_ssize_t read;
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read = grub_file_read (elf->file, (void *) load_addr, phdr->p_filesz);
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if (read != (grub_ssize_t) phdr->p_filesz)
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{
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/* XXX How can we free memory from `load_hook'? */
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grub_error_push ();
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return grub_error (GRUB_ERR_BAD_OS,
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"couldn't read segment from file: "
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"wanted 0x%lx bytes; read 0x%lx bytes",
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phdr->p_filesz, read);
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}
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}
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if (phdr->p_filesz < phdr->p_memsz)
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grub_memset ((void *) (long) (load_addr + phdr->p_filesz),
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0, phdr->p_memsz - phdr->p_filesz);
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load_size += phdr->p_memsz;
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return 0;
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}
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err = grub_elf64_phdr_iterate (_elf, grub_elf64_load_segment, _load_hook);
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if (base)
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*base = load_base;
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if (size)
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*size = load_size;
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return err;
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}
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