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b00fe64f4a
Highlights: - Fix man page markup, whitespace, and typos - Fix sh_info of SHT_GROUP section to point to the correct string - Improve validation in readelf and elfcopy/strip - Handle DWARF 4's DW_AT_high_pc in addr2line Sponsored by: The FreeBSD Foundation
1216 lines
29 KiB
C
1216 lines
29 KiB
C
/*-
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* Copyright (c) 2006-2011 Joseph Koshy
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <assert.h>
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#include <errno.h>
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#include <gelf.h>
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#include <libelf.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "_libelf.h"
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#if ELFTC_HAVE_MMAP
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#include <sys/mman.h>
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#endif
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ELFTC_VCSID("$Id: elf_update.c 3190 2015-05-04 15:23:08Z jkoshy $");
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/*
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* Layout strategy:
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*
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* - Case 1: ELF_F_LAYOUT is asserted
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* In this case the application has full control over where the
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* section header table, program header table, and section data
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* will reside. The library only perform error checks.
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*
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* - Case 2: ELF_F_LAYOUT is not asserted
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*
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* The library will do the object layout using the following
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* ordering:
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* - The executable header is placed first, are required by the
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* ELF specification.
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* - The program header table is placed immediately following the
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* executable header.
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* - Section data, if any, is placed after the program header
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* table, aligned appropriately.
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* - The section header table, if needed, is placed last.
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*
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* There are two sub-cases to be taken care of:
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*
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* - Case 2a: e->e_cmd == ELF_C_READ or ELF_C_RDWR
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*
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* In this sub-case, the underlying ELF object may already have
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* content in it, which the application may have modified. The
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* library will retrieve content from the existing object as
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* needed.
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*
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* - Case 2b: e->e_cmd == ELF_C_WRITE
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*
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* The ELF object is being created afresh in this sub-case;
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* there is no pre-existing content in the underlying ELF
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* object.
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*/
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/*
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* The types of extents in an ELF object.
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*/
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enum elf_extent {
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ELF_EXTENT_EHDR,
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ELF_EXTENT_PHDR,
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ELF_EXTENT_SECTION,
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ELF_EXTENT_SHDR
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};
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/*
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* A extent descriptor, used when laying out an ELF object.
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*/
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struct _Elf_Extent {
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SLIST_ENTRY(_Elf_Extent) ex_next;
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uint64_t ex_start; /* Start of the region. */
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uint64_t ex_size; /* The size of the region. */
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enum elf_extent ex_type; /* Type of region. */
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void *ex_desc; /* Associated descriptor. */
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};
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SLIST_HEAD(_Elf_Extent_List, _Elf_Extent);
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/*
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* Compute the extents of a section, by looking at the data
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* descriptors associated with it. The function returns 1
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* if successful, or zero if an error was detected.
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*/
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static int
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_libelf_compute_section_extents(Elf *e, Elf_Scn *s, off_t rc)
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{
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Elf_Data *d;
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size_t fsz, msz;
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int ec, elftype;
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uint32_t sh_type;
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uint64_t d_align;
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Elf32_Shdr *shdr32;
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Elf64_Shdr *shdr64;
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struct _Libelf_Data *ld;
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uint64_t scn_size, scn_alignment;
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uint64_t sh_align, sh_entsize, sh_offset, sh_size;
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ec = e->e_class;
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shdr32 = &s->s_shdr.s_shdr32;
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shdr64 = &s->s_shdr.s_shdr64;
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if (ec == ELFCLASS32) {
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sh_type = shdr32->sh_type;
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sh_align = (uint64_t) shdr32->sh_addralign;
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sh_entsize = (uint64_t) shdr32->sh_entsize;
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sh_offset = (uint64_t) shdr32->sh_offset;
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sh_size = (uint64_t) shdr32->sh_size;
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} else {
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sh_type = shdr64->sh_type;
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sh_align = shdr64->sh_addralign;
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sh_entsize = shdr64->sh_entsize;
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sh_offset = shdr64->sh_offset;
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sh_size = shdr64->sh_size;
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}
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assert(sh_type != SHT_NULL && sh_type != SHT_NOBITS);
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elftype = _libelf_xlate_shtype(sh_type);
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if (elftype > ELF_T_LAST) {
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LIBELF_SET_ERROR(SECTION, 0);
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return (0);
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}
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if (sh_align == 0)
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sh_align = _libelf_falign(elftype, ec);
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/*
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* Compute the section's size and alignment using the data
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* descriptors associated with the section.
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*/
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if (STAILQ_EMPTY(&s->s_data)) {
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/*
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* The section's content (if any) has not been read in
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* yet. If section is not dirty marked dirty, we can
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* reuse the values in the 'sh_size' and 'sh_offset'
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* fields of the section header.
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*/
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if ((s->s_flags & ELF_F_DIRTY) == 0) {
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/*
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* If the library is doing the layout, then we
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* compute the new start offset for the
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* section based on the current offset and the
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* section's alignment needs.
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*
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* If the application is doing the layout, we
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* can use the value in the 'sh_offset' field
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* in the section header directly.
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*/
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if (e->e_flags & ELF_F_LAYOUT)
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goto updatedescriptor;
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else
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goto computeoffset;
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}
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/*
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* Otherwise, we need to bring in the section's data
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* from the underlying ELF object.
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*/
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if (e->e_cmd != ELF_C_WRITE && elf_getdata(s, NULL) == NULL)
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return (0);
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}
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/*
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* Loop through the section's data descriptors.
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*/
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scn_size = 0L;
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scn_alignment = 0;
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STAILQ_FOREACH(ld, &s->s_data, d_next) {
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d = &ld->d_data;
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/*
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* The data buffer's type is known.
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*/
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if (d->d_type >= ELF_T_NUM) {
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LIBELF_SET_ERROR(DATA, 0);
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return (0);
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}
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/*
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* The data buffer's version is supported.
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*/
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if (d->d_version != e->e_version) {
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LIBELF_SET_ERROR(VERSION, 0);
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return (0);
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}
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/*
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* The buffer's alignment is non-zero and a power of
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* two.
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*/
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if ((d_align = d->d_align) == 0 ||
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(d_align & (d_align - 1))) {
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LIBELF_SET_ERROR(DATA, 0);
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return (0);
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}
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/*
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* The buffer's size should be a multiple of the
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* memory size of the underlying type.
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*/
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msz = _libelf_msize(d->d_type, ec, e->e_version);
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if (d->d_size % msz) {
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LIBELF_SET_ERROR(DATA, 0);
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return (0);
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}
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/*
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* If the application is controlling layout, then the
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* d_offset field should be compatible with the
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* buffer's specified alignment.
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*/
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if ((e->e_flags & ELF_F_LAYOUT) &&
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(d->d_off & (d_align - 1))) {
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LIBELF_SET_ERROR(LAYOUT, 0);
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return (0);
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}
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/*
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* Compute the section's size.
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*/
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if (e->e_flags & ELF_F_LAYOUT) {
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if ((uint64_t) d->d_off + d->d_size > scn_size)
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scn_size = d->d_off + d->d_size;
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} else {
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scn_size = roundup2(scn_size, d->d_align);
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d->d_off = scn_size;
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fsz = _libelf_fsize(d->d_type, ec, d->d_version,
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(size_t) d->d_size / msz);
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scn_size += fsz;
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}
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/*
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* The section's alignment is the maximum alignment
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* needed for its data buffers.
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*/
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if (d_align > scn_alignment)
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scn_alignment = d_align;
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}
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/*
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* If the application is requesting full control over the
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* layout of the section, check the section's specified size,
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* offsets and alignment for sanity.
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*/
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if (e->e_flags & ELF_F_LAYOUT) {
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if (scn_alignment > sh_align ||
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sh_offset % sh_align ||
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sh_size < scn_size ||
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sh_offset % _libelf_falign(elftype, ec)) {
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LIBELF_SET_ERROR(LAYOUT, 0);
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return (0);
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}
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goto updatedescriptor;
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}
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/*
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* Otherwise, compute the values in the section header.
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*
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* The section alignment is the maximum alignment for any of
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* its contained data descriptors.
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*/
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if (scn_alignment > sh_align)
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sh_align = scn_alignment;
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/*
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* If the section entry size is zero, try and fill in an
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* appropriate entry size. Per the elf(5) manual page
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* sections without fixed-size entries should have their
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* 'sh_entsize' field set to zero.
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*/
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if (sh_entsize == 0 &&
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(sh_entsize = _libelf_fsize(elftype, ec, e->e_version,
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(size_t) 1)) == 1)
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sh_entsize = 0;
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sh_size = scn_size;
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computeoffset:
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/*
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* Compute the new offset for the section based on
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* the section's alignment needs.
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*/
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sh_offset = roundup((uint64_t) rc, sh_align);
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/*
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* Update the section header.
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*/
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if (ec == ELFCLASS32) {
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shdr32->sh_addralign = (uint32_t) sh_align;
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shdr32->sh_entsize = (uint32_t) sh_entsize;
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shdr32->sh_offset = (uint32_t) sh_offset;
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shdr32->sh_size = (uint32_t) sh_size;
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} else {
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shdr64->sh_addralign = sh_align;
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shdr64->sh_entsize = sh_entsize;
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shdr64->sh_offset = sh_offset;
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shdr64->sh_size = sh_size;
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}
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updatedescriptor:
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/*
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* Update the section descriptor.
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*/
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s->s_size = sh_size;
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s->s_offset = sh_offset;
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return (1);
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}
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/*
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* Free a list of extent descriptors.
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*/
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static void
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_libelf_release_extents(struct _Elf_Extent_List *extents)
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{
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struct _Elf_Extent *ex;
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while ((ex = SLIST_FIRST(extents)) != NULL) {
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SLIST_REMOVE_HEAD(extents, ex_next);
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free(ex);
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}
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}
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/*
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* Check if an extent 's' defined by [start..start+size) is free.
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* This routine assumes that the given extent list is sorted in order
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* of ascending extent offsets.
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*/
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static int
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_libelf_extent_is_unused(struct _Elf_Extent_List *extents,
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const uint64_t start, const uint64_t size, struct _Elf_Extent **prevt)
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{
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uint64_t tmax, tmin;
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struct _Elf_Extent *t, *pt;
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const uint64_t smax = start + size;
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/* First, look for overlaps with existing extents. */
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pt = NULL;
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SLIST_FOREACH(t, extents, ex_next) {
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tmin = t->ex_start;
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tmax = tmin + t->ex_size;
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if (tmax <= start) {
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/*
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* 't' lies entirely before 's': ...| t |...| s |...
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*/
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pt = t;
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continue;
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} else if (smax <= tmin) {
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/*
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* 's' lies entirely before 't', and after 'pt':
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* ...| pt |...| s |...| t |...
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*/
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assert(pt == NULL ||
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pt->ex_start + pt->ex_size <= start);
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break;
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} else
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/* 's' and 't' overlap. */
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return (0);
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}
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if (prevt)
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*prevt = pt;
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return (1);
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}
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/*
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* Insert an extent into the list of extents.
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*/
|
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static int
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_libelf_insert_extent(struct _Elf_Extent_List *extents, int type,
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uint64_t start, uint64_t size, void *desc)
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{
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struct _Elf_Extent *ex, *prevt;
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assert(type >= ELF_EXTENT_EHDR && type <= ELF_EXTENT_SHDR);
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prevt = NULL;
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|
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/*
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* If the requested range overlaps with an existing extent,
|
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* signal an error.
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*/
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if (!_libelf_extent_is_unused(extents, start, size, &prevt)) {
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LIBELF_SET_ERROR(LAYOUT, 0);
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return (0);
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}
|
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|
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/* Allocate and fill in a new extent descriptor. */
|
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if ((ex = malloc(sizeof(struct _Elf_Extent))) == NULL) {
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LIBELF_SET_ERROR(RESOURCE, errno);
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return (0);
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}
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ex->ex_start = start;
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ex->ex_size = size;
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ex->ex_desc = desc;
|
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ex->ex_type = type;
|
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|
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/* Insert the region descriptor into the list. */
|
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if (prevt)
|
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SLIST_INSERT_AFTER(prevt, ex, ex_next);
|
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else
|
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SLIST_INSERT_HEAD(extents, ex, ex_next);
|
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return (1);
|
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}
|
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|
|
/*
|
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* Recompute section layout.
|
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*/
|
|
|
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static off_t
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_libelf_resync_sections(Elf *e, off_t rc, struct _Elf_Extent_List *extents)
|
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{
|
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int ec;
|
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Elf_Scn *s;
|
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size_t sh_type;
|
|
|
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ec = e->e_class;
|
|
|
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/*
|
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* Make a pass through sections, computing the extent of each
|
|
* section.
|
|
*/
|
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STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) {
|
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if (ec == ELFCLASS32)
|
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sh_type = s->s_shdr.s_shdr32.sh_type;
|
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else
|
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sh_type = s->s_shdr.s_shdr64.sh_type;
|
|
|
|
if (sh_type == SHT_NOBITS || sh_type == SHT_NULL)
|
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continue;
|
|
|
|
if (_libelf_compute_section_extents(e, s, rc) == 0)
|
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return ((off_t) -1);
|
|
|
|
if (s->s_size == 0)
|
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continue;
|
|
|
|
if (!_libelf_insert_extent(extents, ELF_EXTENT_SECTION,
|
|
s->s_offset, s->s_size, s))
|
|
return ((off_t) -1);
|
|
|
|
if ((size_t) rc < s->s_offset + s->s_size)
|
|
rc = (off_t) (s->s_offset + s->s_size);
|
|
}
|
|
|
|
return (rc);
|
|
}
|
|
|
|
/*
|
|
* Recompute the layout of the ELF object and update the internal data
|
|
* structures associated with the ELF descriptor.
|
|
*
|
|
* Returns the size in bytes the ELF object would occupy in its file
|
|
* representation.
|
|
*
|
|
* After a successful call to this function, the following structures
|
|
* are updated:
|
|
*
|
|
* - The ELF header is updated.
|
|
* - All extents in the ELF object are sorted in order of ascending
|
|
* addresses. Sections have their section header table entries
|
|
* updated. An error is signalled if an overlap was detected among
|
|
* extents.
|
|
* - Data descriptors associated with sections are checked for valid
|
|
* types, offsets and alignment.
|
|
*
|
|
* After a resync_elf() successfully returns, the ELF descriptor is
|
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* ready for being handed over to _libelf_write_elf().
|
|
*/
|
|
|
|
static off_t
|
|
_libelf_resync_elf(Elf *e, struct _Elf_Extent_List *extents)
|
|
{
|
|
int ec, eh_class;
|
|
unsigned int eh_byteorder, eh_version;
|
|
size_t align, fsz;
|
|
size_t phnum, shnum;
|
|
off_t rc, phoff, shoff;
|
|
void *ehdr, *phdr;
|
|
Elf32_Ehdr *eh32;
|
|
Elf64_Ehdr *eh64;
|
|
|
|
rc = 0;
|
|
|
|
ec = e->e_class;
|
|
|
|
assert(ec == ELFCLASS32 || ec == ELFCLASS64);
|
|
|
|
/*
|
|
* Prepare the EHDR.
|
|
*/
|
|
if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
|
|
return ((off_t) -1);
|
|
|
|
eh32 = ehdr;
|
|
eh64 = ehdr;
|
|
|
|
if (ec == ELFCLASS32) {
|
|
eh_byteorder = eh32->e_ident[EI_DATA];
|
|
eh_class = eh32->e_ident[EI_CLASS];
|
|
phoff = (off_t) eh32->e_phoff;
|
|
shoff = (off_t) eh32->e_shoff;
|
|
eh_version = eh32->e_version;
|
|
} else {
|
|
eh_byteorder = eh64->e_ident[EI_DATA];
|
|
eh_class = eh64->e_ident[EI_CLASS];
|
|
phoff = (off_t) eh64->e_phoff;
|
|
shoff = (off_t) eh64->e_shoff;
|
|
eh_version = eh64->e_version;
|
|
}
|
|
|
|
if (phoff < 0 || shoff < 0) {
|
|
LIBELF_SET_ERROR(HEADER, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
if (eh_version == EV_NONE)
|
|
eh_version = EV_CURRENT;
|
|
|
|
if (eh_version != e->e_version) { /* always EV_CURRENT */
|
|
LIBELF_SET_ERROR(VERSION, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
if (eh_class != e->e_class) {
|
|
LIBELF_SET_ERROR(CLASS, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
if (e->e_cmd != ELF_C_WRITE && eh_byteorder != e->e_byteorder) {
|
|
LIBELF_SET_ERROR(HEADER, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
shnum = e->e_u.e_elf.e_nscn;
|
|
phnum = e->e_u.e_elf.e_nphdr;
|
|
|
|
e->e_byteorder = eh_byteorder;
|
|
|
|
#define INITIALIZE_EHDR(E,EC,V) do { \
|
|
unsigned int _version = (unsigned int) (V); \
|
|
(E)->e_ident[EI_MAG0] = ELFMAG0; \
|
|
(E)->e_ident[EI_MAG1] = ELFMAG1; \
|
|
(E)->e_ident[EI_MAG2] = ELFMAG2; \
|
|
(E)->e_ident[EI_MAG3] = ELFMAG3; \
|
|
(E)->e_ident[EI_CLASS] = (unsigned char) (EC); \
|
|
(E)->e_ident[EI_VERSION] = (_version & 0xFFU); \
|
|
(E)->e_ehsize = (uint16_t) _libelf_fsize(ELF_T_EHDR, \
|
|
(EC), _version, (size_t) 1); \
|
|
(E)->e_phentsize = (uint16_t) ((phnum == 0) ? 0 : \
|
|
_libelf_fsize(ELF_T_PHDR, (EC), _version, \
|
|
(size_t) 1)); \
|
|
(E)->e_shentsize = (uint16_t) _libelf_fsize(ELF_T_SHDR, \
|
|
(EC), _version, (size_t) 1); \
|
|
} while (0)
|
|
|
|
if (ec == ELFCLASS32)
|
|
INITIALIZE_EHDR(eh32, ec, eh_version);
|
|
else
|
|
INITIALIZE_EHDR(eh64, ec, eh_version);
|
|
|
|
(void) elf_flagehdr(e, ELF_C_SET, ELF_F_DIRTY);
|
|
|
|
rc += (off_t) _libelf_fsize(ELF_T_EHDR, ec, eh_version, (size_t) 1);
|
|
|
|
if (!_libelf_insert_extent(extents, ELF_EXTENT_EHDR, 0, (uint64_t) rc,
|
|
ehdr))
|
|
return ((off_t) -1);
|
|
|
|
/*
|
|
* Compute the layout the program header table, if one is
|
|
* present. The program header table needs to be aligned to a
|
|
* `natural' boundary.
|
|
*/
|
|
if (phnum) {
|
|
fsz = _libelf_fsize(ELF_T_PHDR, ec, eh_version, phnum);
|
|
align = _libelf_falign(ELF_T_PHDR, ec);
|
|
|
|
if (e->e_flags & ELF_F_LAYOUT) {
|
|
/*
|
|
* Check offsets for sanity.
|
|
*/
|
|
if (rc > phoff) {
|
|
LIBELF_SET_ERROR(LAYOUT, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
if (phoff % (off_t) align) {
|
|
LIBELF_SET_ERROR(LAYOUT, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
} else
|
|
phoff = roundup(rc, (off_t) align);
|
|
|
|
rc = phoff + (off_t) fsz;
|
|
|
|
phdr = _libelf_getphdr(e, ec);
|
|
|
|
if (!_libelf_insert_extent(extents, ELF_EXTENT_PHDR,
|
|
(uint64_t) phoff, fsz, phdr))
|
|
return ((off_t) -1);
|
|
} else
|
|
phoff = 0;
|
|
|
|
/*
|
|
* Compute the layout of the sections associated with the
|
|
* file.
|
|
*/
|
|
|
|
if (e->e_cmd != ELF_C_WRITE &&
|
|
(e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
|
|
_libelf_load_section_headers(e, ehdr) == 0)
|
|
return ((off_t) -1);
|
|
|
|
if ((rc = _libelf_resync_sections(e, rc, extents)) < 0)
|
|
return ((off_t) -1);
|
|
|
|
/*
|
|
* Compute the space taken up by the section header table, if
|
|
* one is needed.
|
|
*
|
|
* If ELF_F_LAYOUT has been asserted, the application may have
|
|
* placed the section header table in between existing
|
|
* sections, so the net size of the file need not increase due
|
|
* to the presence of the section header table.
|
|
*
|
|
* If the library is responsible for laying out the object,
|
|
* the section header table is placed after section data.
|
|
*/
|
|
if (shnum) {
|
|
fsz = _libelf_fsize(ELF_T_SHDR, ec, eh_version, shnum);
|
|
align = _libelf_falign(ELF_T_SHDR, ec);
|
|
|
|
if (e->e_flags & ELF_F_LAYOUT) {
|
|
if (shoff % (off_t) align) {
|
|
LIBELF_SET_ERROR(LAYOUT, 0);
|
|
return ((off_t) -1);
|
|
}
|
|
} else
|
|
shoff = roundup(rc, (off_t) align);
|
|
|
|
if (shoff + (off_t) fsz > rc)
|
|
rc = shoff + (off_t) fsz;
|
|
|
|
if (!_libelf_insert_extent(extents, ELF_EXTENT_SHDR,
|
|
(uint64_t) shoff, fsz, NULL))
|
|
return ((off_t) -1);
|
|
} else
|
|
shoff = 0;
|
|
|
|
/*
|
|
* Set the fields of the Executable Header that could potentially use
|
|
* extended numbering.
|
|
*/
|
|
_libelf_setphnum(e, ehdr, ec, phnum);
|
|
_libelf_setshnum(e, ehdr, ec, shnum);
|
|
|
|
/*
|
|
* Update the `e_phoff' and `e_shoff' fields if the library is
|
|
* doing the layout.
|
|
*/
|
|
if ((e->e_flags & ELF_F_LAYOUT) == 0) {
|
|
if (ec == ELFCLASS32) {
|
|
eh32->e_phoff = (uint32_t) phoff;
|
|
eh32->e_shoff = (uint32_t) shoff;
|
|
} else {
|
|
eh64->e_phoff = (uint64_t) phoff;
|
|
eh64->e_shoff = (uint64_t) shoff;
|
|
}
|
|
}
|
|
|
|
return (rc);
|
|
}
|
|
|
|
/*
|
|
* Write out the contents of an ELF section.
|
|
*/
|
|
|
|
static off_t
|
|
_libelf_write_scn(Elf *e, unsigned char *nf, struct _Elf_Extent *ex)
|
|
{
|
|
int ec;
|
|
off_t rc;
|
|
Elf_Scn *s;
|
|
int elftype;
|
|
Elf_Data *d, dst;
|
|
uint32_t sh_type;
|
|
struct _Libelf_Data *ld;
|
|
uint64_t sh_off, sh_size;
|
|
size_t fsz, msz, nobjects;
|
|
|
|
assert(ex->ex_type == ELF_EXTENT_SECTION);
|
|
|
|
s = ex->ex_desc;
|
|
rc = (off_t) ex->ex_start;
|
|
|
|
if ((ec = e->e_class) == ELFCLASS32) {
|
|
sh_type = s->s_shdr.s_shdr32.sh_type;
|
|
sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
|
|
} else {
|
|
sh_type = s->s_shdr.s_shdr64.sh_type;
|
|
sh_size = s->s_shdr.s_shdr64.sh_size;
|
|
}
|
|
|
|
/*
|
|
* Ignore sections that do not allocate space in the file.
|
|
*/
|
|
if (sh_type == SHT_NOBITS || sh_type == SHT_NULL || sh_size == 0)
|
|
return (rc);
|
|
|
|
elftype = _libelf_xlate_shtype(sh_type);
|
|
assert(elftype >= ELF_T_FIRST && elftype <= ELF_T_LAST);
|
|
|
|
sh_off = s->s_offset;
|
|
assert(sh_off % _libelf_falign(elftype, ec) == 0);
|
|
|
|
/*
|
|
* If the section has a `rawdata' descriptor, and the section
|
|
* contents have not been modified, use its contents directly.
|
|
* The `s_rawoff' member contains the offset into the original
|
|
* file, while `s_offset' contains its new location in the
|
|
* destination.
|
|
*/
|
|
|
|
if (STAILQ_EMPTY(&s->s_data)) {
|
|
|
|
if ((d = elf_rawdata(s, NULL)) == NULL)
|
|
return ((off_t) -1);
|
|
|
|
STAILQ_FOREACH(ld, &s->s_rawdata, d_next) {
|
|
|
|
d = &ld->d_data;
|
|
|
|
if ((uint64_t) rc < sh_off + d->d_off)
|
|
(void) memset(nf + rc,
|
|
LIBELF_PRIVATE(fillchar),
|
|
(size_t) (sh_off + d->d_off -
|
|
(uint64_t) rc));
|
|
rc = (off_t) (sh_off + d->d_off);
|
|
|
|
assert(d->d_buf != NULL);
|
|
assert(d->d_type == ELF_T_BYTE);
|
|
assert(d->d_version == e->e_version);
|
|
|
|
(void) memcpy(nf + rc,
|
|
e->e_rawfile + s->s_rawoff + d->d_off,
|
|
(size_t) d->d_size);
|
|
|
|
rc += (off_t) d->d_size;
|
|
}
|
|
|
|
return (rc);
|
|
}
|
|
|
|
/*
|
|
* Iterate over the set of data descriptors for this section.
|
|
* The prior call to _libelf_resync_elf() would have setup the
|
|
* descriptors for this step.
|
|
*/
|
|
|
|
dst.d_version = e->e_version;
|
|
|
|
STAILQ_FOREACH(ld, &s->s_data, d_next) {
|
|
|
|
d = &ld->d_data;
|
|
|
|
msz = _libelf_msize(d->d_type, ec, e->e_version);
|
|
|
|
if ((uint64_t) rc < sh_off + d->d_off)
|
|
(void) memset(nf + rc,
|
|
LIBELF_PRIVATE(fillchar),
|
|
(size_t) (sh_off + d->d_off - (uint64_t) rc));
|
|
|
|
rc = (off_t) (sh_off + d->d_off);
|
|
|
|
assert(d->d_buf != NULL);
|
|
assert(d->d_version == e->e_version);
|
|
assert(d->d_size % msz == 0);
|
|
|
|
nobjects = (size_t) (d->d_size / msz);
|
|
|
|
fsz = _libelf_fsize(d->d_type, ec, e->e_version, nobjects);
|
|
|
|
dst.d_buf = nf + rc;
|
|
dst.d_size = fsz;
|
|
|
|
if (_libelf_xlate(&dst, d, e->e_byteorder, ec, ELF_TOFILE) ==
|
|
NULL)
|
|
return ((off_t) -1);
|
|
|
|
rc += (off_t) fsz;
|
|
}
|
|
|
|
return (rc);
|
|
}
|
|
|
|
/*
|
|
* Write out an ELF Executable Header.
|
|
*/
|
|
|
|
static off_t
|
|
_libelf_write_ehdr(Elf *e, unsigned char *nf, struct _Elf_Extent *ex)
|
|
{
|
|
int ec;
|
|
void *ehdr;
|
|
size_t fsz, msz;
|
|
Elf_Data dst, src;
|
|
|
|
assert(ex->ex_type == ELF_EXTENT_EHDR);
|
|
assert(ex->ex_start == 0); /* Ehdr always comes first. */
|
|
|
|
ec = e->e_class;
|
|
|
|
ehdr = _libelf_ehdr(e, ec, 0);
|
|
assert(ehdr != NULL);
|
|
|
|
fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1);
|
|
msz = _libelf_msize(ELF_T_EHDR, ec, e->e_version);
|
|
|
|
(void) memset(&dst, 0, sizeof(dst));
|
|
(void) memset(&src, 0, sizeof(src));
|
|
|
|
src.d_buf = ehdr;
|
|
src.d_size = msz;
|
|
src.d_type = ELF_T_EHDR;
|
|
src.d_version = dst.d_version = e->e_version;
|
|
|
|
dst.d_buf = nf;
|
|
dst.d_size = fsz;
|
|
|
|
if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) ==
|
|
NULL)
|
|
return ((off_t) -1);
|
|
|
|
return ((off_t) fsz);
|
|
}
|
|
|
|
/*
|
|
* Write out an ELF program header table.
|
|
*/
|
|
|
|
static off_t
|
|
_libelf_write_phdr(Elf *e, unsigned char *nf, struct _Elf_Extent *ex)
|
|
{
|
|
int ec;
|
|
void *ehdr;
|
|
Elf32_Ehdr *eh32;
|
|
Elf64_Ehdr *eh64;
|
|
Elf_Data dst, src;
|
|
size_t fsz, phnum;
|
|
uint64_t phoff;
|
|
|
|
assert(ex->ex_type == ELF_EXTENT_PHDR);
|
|
|
|
ec = e->e_class;
|
|
ehdr = _libelf_ehdr(e, ec, 0);
|
|
phnum = e->e_u.e_elf.e_nphdr;
|
|
|
|
assert(phnum > 0);
|
|
|
|
if (ec == ELFCLASS32) {
|
|
eh32 = (Elf32_Ehdr *) ehdr;
|
|
phoff = (uint64_t) eh32->e_phoff;
|
|
} else {
|
|
eh64 = (Elf64_Ehdr *) ehdr;
|
|
phoff = eh64->e_phoff;
|
|
}
|
|
|
|
assert(phoff > 0);
|
|
assert(ex->ex_start == phoff);
|
|
assert(phoff % _libelf_falign(ELF_T_PHDR, ec) == 0);
|
|
|
|
(void) memset(&dst, 0, sizeof(dst));
|
|
(void) memset(&src, 0, sizeof(src));
|
|
|
|
fsz = _libelf_fsize(ELF_T_PHDR, ec, e->e_version, phnum);
|
|
assert(fsz > 0);
|
|
|
|
src.d_buf = _libelf_getphdr(e, ec);
|
|
src.d_version = dst.d_version = e->e_version;
|
|
src.d_type = ELF_T_PHDR;
|
|
src.d_size = phnum * _libelf_msize(ELF_T_PHDR, ec,
|
|
e->e_version);
|
|
|
|
dst.d_size = fsz;
|
|
dst.d_buf = nf + ex->ex_start;
|
|
|
|
if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) ==
|
|
NULL)
|
|
return ((off_t) -1);
|
|
|
|
return ((off_t) (phoff + fsz));
|
|
}
|
|
|
|
/*
|
|
* Write out an ELF section header table.
|
|
*/
|
|
|
|
static off_t
|
|
_libelf_write_shdr(Elf *e, unsigned char *nf, struct _Elf_Extent *ex)
|
|
{
|
|
int ec;
|
|
void *ehdr;
|
|
Elf_Scn *scn;
|
|
uint64_t shoff;
|
|
Elf32_Ehdr *eh32;
|
|
Elf64_Ehdr *eh64;
|
|
size_t fsz, nscn;
|
|
Elf_Data dst, src;
|
|
|
|
assert(ex->ex_type == ELF_EXTENT_SHDR);
|
|
|
|
ec = e->e_class;
|
|
ehdr = _libelf_ehdr(e, ec, 0);
|
|
nscn = e->e_u.e_elf.e_nscn;
|
|
|
|
if (ec == ELFCLASS32) {
|
|
eh32 = (Elf32_Ehdr *) ehdr;
|
|
shoff = (uint64_t) eh32->e_shoff;
|
|
} else {
|
|
eh64 = (Elf64_Ehdr *) ehdr;
|
|
shoff = eh64->e_shoff;
|
|
}
|
|
|
|
assert(nscn > 0);
|
|
assert(shoff % _libelf_falign(ELF_T_SHDR, ec) == 0);
|
|
assert(ex->ex_start == shoff);
|
|
|
|
(void) memset(&dst, 0, sizeof(dst));
|
|
(void) memset(&src, 0, sizeof(src));
|
|
|
|
src.d_type = ELF_T_SHDR;
|
|
src.d_size = _libelf_msize(ELF_T_SHDR, ec, e->e_version);
|
|
src.d_version = dst.d_version = e->e_version;
|
|
|
|
fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1);
|
|
|
|
STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) {
|
|
if (ec == ELFCLASS32)
|
|
src.d_buf = &scn->s_shdr.s_shdr32;
|
|
else
|
|
src.d_buf = &scn->s_shdr.s_shdr64;
|
|
|
|
dst.d_size = fsz;
|
|
dst.d_buf = nf + ex->ex_start + scn->s_ndx * fsz;
|
|
|
|
if (_libelf_xlate(&dst, &src, e->e_byteorder, ec,
|
|
ELF_TOFILE) == NULL)
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
return ((off_t) (ex->ex_start + nscn * fsz));
|
|
}
|
|
|
|
/*
|
|
* Write out the file image.
|
|
*
|
|
* The original file could have been mapped in with an ELF_C_RDWR
|
|
* command and the application could have added new content or
|
|
* re-arranged its sections before calling elf_update(). Consequently
|
|
* its not safe to work `in place' on the original file. So we
|
|
* malloc() the required space for the updated ELF object and build
|
|
* the object there and write it out to the underlying file at the
|
|
* end. Note that the application may have opened the underlying file
|
|
* in ELF_C_RDWR and only retrieved/modified a few sections. We take
|
|
* care to avoid translating file sections unnecessarily.
|
|
*
|
|
* Gaps in the coverage of the file by the file's sections will be
|
|
* filled with the fill character set by elf_fill(3).
|
|
*/
|
|
|
|
static off_t
|
|
_libelf_write_elf(Elf *e, off_t newsize, struct _Elf_Extent_List *extents)
|
|
{
|
|
off_t nrc, rc;
|
|
Elf_Scn *scn, *tscn;
|
|
struct _Elf_Extent *ex;
|
|
unsigned char *newfile;
|
|
|
|
assert(e->e_kind == ELF_K_ELF);
|
|
assert(e->e_cmd == ELF_C_RDWR || e->e_cmd == ELF_C_WRITE);
|
|
assert(e->e_fd >= 0);
|
|
|
|
if ((newfile = malloc((size_t) newsize)) == NULL) {
|
|
LIBELF_SET_ERROR(RESOURCE, errno);
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
nrc = rc = 0;
|
|
SLIST_FOREACH(ex, extents, ex_next) {
|
|
|
|
/* Fill inter-extent gaps. */
|
|
if (ex->ex_start > (size_t) rc)
|
|
(void) memset(newfile + rc, LIBELF_PRIVATE(fillchar),
|
|
(size_t) (ex->ex_start - (uint64_t) rc));
|
|
|
|
switch (ex->ex_type) {
|
|
case ELF_EXTENT_EHDR:
|
|
if ((nrc = _libelf_write_ehdr(e, newfile, ex)) < 0)
|
|
goto error;
|
|
break;
|
|
|
|
case ELF_EXTENT_PHDR:
|
|
if ((nrc = _libelf_write_phdr(e, newfile, ex)) < 0)
|
|
goto error;
|
|
break;
|
|
|
|
case ELF_EXTENT_SECTION:
|
|
if ((nrc = _libelf_write_scn(e, newfile, ex)) < 0)
|
|
goto error;
|
|
break;
|
|
|
|
case ELF_EXTENT_SHDR:
|
|
if ((nrc = _libelf_write_shdr(e, newfile, ex)) < 0)
|
|
goto error;
|
|
break;
|
|
|
|
default:
|
|
assert(0);
|
|
break;
|
|
}
|
|
|
|
assert(ex->ex_start + ex->ex_size == (size_t) nrc);
|
|
assert(rc < nrc);
|
|
|
|
rc = nrc;
|
|
}
|
|
|
|
assert(rc == newsize);
|
|
|
|
/*
|
|
* For regular files, throw away existing file content and
|
|
* unmap any existing mappings.
|
|
*/
|
|
if ((e->e_flags & LIBELF_F_SPECIAL_FILE) == 0) {
|
|
if (ftruncate(e->e_fd, (off_t) 0) < 0 ||
|
|
lseek(e->e_fd, (off_t) 0, SEEK_SET)) {
|
|
LIBELF_SET_ERROR(IO, errno);
|
|
goto error;
|
|
}
|
|
#if ELFTC_HAVE_MMAP
|
|
if (e->e_flags & LIBELF_F_RAWFILE_MMAP) {
|
|
assert(e->e_rawfile != NULL);
|
|
assert(e->e_cmd == ELF_C_RDWR);
|
|
if (munmap(e->e_rawfile, e->e_rawsize) < 0) {
|
|
LIBELF_SET_ERROR(IO, errno);
|
|
goto error;
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Write out the new contents.
|
|
*/
|
|
if (write(e->e_fd, newfile, (size_t) newsize) != newsize) {
|
|
LIBELF_SET_ERROR(IO, errno);
|
|
goto error;
|
|
}
|
|
|
|
/*
|
|
* For files opened in ELF_C_RDWR mode, set up the new 'raw'
|
|
* contents.
|
|
*/
|
|
if (e->e_cmd == ELF_C_RDWR) {
|
|
assert(e->e_rawfile != NULL);
|
|
assert((e->e_flags & LIBELF_F_RAWFILE_MALLOC) ||
|
|
(e->e_flags & LIBELF_F_RAWFILE_MMAP));
|
|
if (e->e_flags & LIBELF_F_RAWFILE_MALLOC) {
|
|
free(e->e_rawfile);
|
|
e->e_rawfile = newfile;
|
|
newfile = NULL;
|
|
}
|
|
#if ELFTC_HAVE_MMAP
|
|
else if (e->e_flags & LIBELF_F_RAWFILE_MMAP) {
|
|
if ((e->e_rawfile = mmap(NULL, (size_t) newsize,
|
|
PROT_READ, MAP_PRIVATE, e->e_fd, (off_t) 0)) ==
|
|
MAP_FAILED) {
|
|
LIBELF_SET_ERROR(IO, errno);
|
|
goto error;
|
|
}
|
|
}
|
|
#endif /* ELFTC_HAVE_MMAP */
|
|
|
|
/* Record the new size of the file. */
|
|
e->e_rawsize = (size_t) newsize;
|
|
} else {
|
|
/* File opened in ELF_C_WRITE mode. */
|
|
assert(e->e_rawfile == NULL);
|
|
}
|
|
|
|
/*
|
|
* Reset flags, remove existing section descriptors and
|
|
* {E,P}HDR pointers so that a subsequent elf_get{e,p}hdr()
|
|
* and elf_getscn() will function correctly.
|
|
*/
|
|
|
|
e->e_flags &= ~ELF_F_DIRTY;
|
|
|
|
STAILQ_FOREACH_SAFE(scn, &e->e_u.e_elf.e_scn, s_next, tscn)
|
|
_libelf_release_scn(scn);
|
|
|
|
if (e->e_class == ELFCLASS32) {
|
|
free(e->e_u.e_elf.e_ehdr.e_ehdr32);
|
|
if (e->e_u.e_elf.e_phdr.e_phdr32)
|
|
free(e->e_u.e_elf.e_phdr.e_phdr32);
|
|
|
|
e->e_u.e_elf.e_ehdr.e_ehdr32 = NULL;
|
|
e->e_u.e_elf.e_phdr.e_phdr32 = NULL;
|
|
} else {
|
|
free(e->e_u.e_elf.e_ehdr.e_ehdr64);
|
|
if (e->e_u.e_elf.e_phdr.e_phdr64)
|
|
free(e->e_u.e_elf.e_phdr.e_phdr64);
|
|
|
|
e->e_u.e_elf.e_ehdr.e_ehdr64 = NULL;
|
|
e->e_u.e_elf.e_phdr.e_phdr64 = NULL;
|
|
}
|
|
|
|
/* Free the temporary buffer. */
|
|
if (newfile)
|
|
free(newfile);
|
|
|
|
return (rc);
|
|
|
|
error:
|
|
free(newfile);
|
|
|
|
return ((off_t) -1);
|
|
}
|
|
|
|
/*
|
|
* Update an ELF object.
|
|
*/
|
|
|
|
off_t
|
|
elf_update(Elf *e, Elf_Cmd c)
|
|
{
|
|
int ec;
|
|
off_t rc;
|
|
struct _Elf_Extent_List extents;
|
|
|
|
rc = (off_t) -1;
|
|
|
|
if (e == NULL || e->e_kind != ELF_K_ELF ||
|
|
(c != ELF_C_NULL && c != ELF_C_WRITE)) {
|
|
LIBELF_SET_ERROR(ARGUMENT, 0);
|
|
return (rc);
|
|
}
|
|
|
|
if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) {
|
|
LIBELF_SET_ERROR(CLASS, 0);
|
|
return (rc);
|
|
}
|
|
|
|
if (e->e_version == EV_NONE)
|
|
e->e_version = EV_CURRENT;
|
|
|
|
if (c == ELF_C_WRITE && e->e_cmd == ELF_C_READ) {
|
|
LIBELF_SET_ERROR(MODE, 0);
|
|
return (rc);
|
|
}
|
|
|
|
SLIST_INIT(&extents);
|
|
|
|
if ((rc = _libelf_resync_elf(e, &extents)) < 0)
|
|
goto done;
|
|
|
|
if (c == ELF_C_NULL)
|
|
goto done;
|
|
|
|
if (e->e_fd < 0) {
|
|
rc = (off_t) -1;
|
|
LIBELF_SET_ERROR(SEQUENCE, 0);
|
|
goto done;
|
|
}
|
|
|
|
rc = _libelf_write_elf(e, rc, &extents);
|
|
|
|
done:
|
|
_libelf_release_extents(&extents);
|
|
return (rc);
|
|
}
|