910 lines
21 KiB
C
910 lines
21 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <inttypes.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "elfparsing.h"
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#include "rmodule.h"
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#include <commonlib/rmodule-defs.h>
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/*
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* Architecture specific support operations.
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*/
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static int valid_reloc_386(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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/* Only these 2 relocations are expected to be found. */
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return (type == R_386_32 || type == R_386_PC32);
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}
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static int should_emit_386(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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/* R_386_32 relocations are absolute. Must emit these. */
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return (type == R_386_32);
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}
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static int valid_reloc_amd64(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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/*
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* Relocation R_AMD64_32S is not allowed. It can only be safely used in protected mode,
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* and when the address pointed to is below 2 GiB in long mode.
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* Using it in assembly operations will break compilation with error:
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* E: Invalid reloc type: 11
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*/
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/* Only these 5 relocations are expected to be found. */
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return (type == R_AMD64_64 ||
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type == R_AMD64_PC64 ||
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type == R_AMD64_32 ||
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type == R_AMD64_PC32 ||
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/*
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* binutils 2.31 introduced R_AMD64_PLT32 for non local
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* functions. As we don't care about procedure linkage
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* table entries handle it as R_X86_64_PC32.
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*/
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type == R_AMD64_PLT32);
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}
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static int should_emit_amd64(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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/* Only emit absolute relocations */
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return (type == R_AMD64_64 ||
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type == R_AMD64_32);
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}
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static int valid_reloc_arm(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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/* Only these 6 relocations are expected to be found. */
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return (type == R_ARM_ABS32 || type == R_ARM_THM_PC22 ||
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type == R_ARM_THM_JUMP24 || type == R_ARM_V4BX ||
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type == R_ARM_CALL || type == R_ARM_JUMP24);
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}
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static int should_emit_arm(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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/* R_ARM_ABS32 relocations are absolute. Must emit these. */
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return (type == R_ARM_ABS32);
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}
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static int valid_reloc_aarch64(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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return (type == R_AARCH64_ADR_PREL_PG_HI21 ||
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type == R_AARCH64_ADD_ABS_LO12_NC ||
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type == R_AARCH64_LDST8_ABS_LO12_NC ||
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type == R_AARCH64_CONDBR19 ||
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type == R_AARCH64_JUMP26 ||
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type == R_AARCH64_LDST32_ABS_LO12_NC ||
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type == R_AARCH64_LDST64_ABS_LO12_NC ||
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type == R_AARCH64_CALL26 ||
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type == R_AARCH64_ABS64 ||
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type == R_AARCH64_LD_PREL_LO19 ||
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type == R_AARCH64_ADR_PREL_LO21);
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}
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static int should_emit_aarch64(Elf64_Rela *rel)
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{
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int type;
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type = ELF64_R_TYPE(rel->r_info);
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return (type == R_AARCH64_ABS64);
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}
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static const struct arch_ops reloc_ops[] = {
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{
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.arch = EM_386,
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.valid_type = valid_reloc_386,
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.should_emit = should_emit_386,
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},
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{
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.arch = EM_X86_64,
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.valid_type = valid_reloc_amd64,
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.should_emit = should_emit_amd64,
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},
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{
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.arch = EM_ARM,
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.valid_type = valid_reloc_arm,
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.should_emit = should_emit_arm,
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},
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{
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.arch = EM_AARCH64,
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.valid_type = valid_reloc_aarch64,
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.should_emit = should_emit_aarch64,
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},
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};
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static int relocation_for_absolute_symbol(struct rmod_context *ctx, Elf64_Rela *r)
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{
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Elf64_Sym *s = &ctx->pelf.syms[ELF64_R_SYM(r->r_info)];
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if (s->st_shndx == SHN_ABS) {
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DEBUG("Omitting relocation for absolute symbol: %s\n",
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&ctx->strtab[s->st_name]);
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return 1;
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}
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return 0;
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}
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static int relocation_for_weak_extern_symbols(struct rmod_context *ctx, Elf64_Rela *r)
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{
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Elf64_Sym *s = &ctx->pelf.syms[ELF64_R_SYM(r->r_info)];
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if (ELF64_ST_BIND(s->st_info) == STB_WEAK && ELF64_ST_TYPE(s->st_info) == STT_NOTYPE) {
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DEBUG("Omitting relocation for undefined extern: %s\n",
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&ctx->strtab[s->st_name]);
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return 1;
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}
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return 0;
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}
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/*
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* Relocation processing loops.
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*/
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static int for_each_reloc(struct rmod_context *ctx, struct reloc_filter *f,
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int do_emit)
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{
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Elf64_Half i;
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struct parsed_elf *pelf = &ctx->pelf;
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for (i = 0; i < pelf->ehdr.e_shnum; i++) {
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Elf64_Shdr *shdr;
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Elf64_Rela *relocs;
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Elf64_Xword nrelocs;
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Elf64_Xword j;
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relocs = pelf->relocs[i];
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/* No relocations in this section. */
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if (relocs == NULL)
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continue;
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shdr = &pelf->shdr[i];
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nrelocs = shdr->sh_size / shdr->sh_entsize;
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for (j = 0; j < nrelocs; j++) {
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int filter_emit = 1;
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Elf64_Rela *r = &relocs[j];
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if (!ctx->ops->valid_type(r)) {
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ERROR("Invalid reloc type: %u\n",
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(unsigned int)ELF64_R_TYPE(r->r_info));
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if ((ctx->ops->arch == EM_X86_64) &&
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(ELF64_R_TYPE(r->r_info) == R_AMD64_32S))
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ERROR("Illegal use of 32bit sign extended addressing at offset 0x%x\n",
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(unsigned int)r->r_offset);
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return -1;
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}
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if (relocation_for_absolute_symbol(ctx, r))
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continue;
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if (relocation_for_weak_extern_symbols(ctx, r))
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continue;
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/* Allow the provided filter to have precedence. */
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if (f != NULL) {
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filter_emit = f->filter(f, r);
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if (filter_emit < 0)
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return filter_emit;
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}
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if (filter_emit && ctx->ops->should_emit(r)) {
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int n = ctx->nrelocs;
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if (do_emit)
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ctx->emitted_relocs[n] = r->r_offset;
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ctx->nrelocs++;
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}
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}
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}
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return 0;
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}
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static int find_program_segment(struct rmod_context *ctx)
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{
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int i;
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int nsegments;
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struct parsed_elf *pelf;
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Elf64_Phdr *phdr = NULL;
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pelf = &ctx->pelf;
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/* There should only be a single loadable segment. */
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nsegments = 0;
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for (i = 0; i < pelf->ehdr.e_phnum; i++) {
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if (pelf->phdr[i].p_type != PT_LOAD)
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continue;
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phdr = &pelf->phdr[i];
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nsegments++;
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}
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if (nsegments != 1) {
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ERROR("Unexpected number of loadable segments: %d.\n",
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nsegments);
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return -1;
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}
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INFO("Segment at 0x%0llx, file size 0x%0llx, mem size 0x%0llx.\n",
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(long long)phdr->p_vaddr, (long long)phdr->p_filesz,
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(long long)phdr->p_memsz);
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ctx->phdr = phdr;
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return 0;
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}
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static int
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filter_relocation_sections(struct rmod_context *ctx)
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{
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int i;
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const char *shstrtab;
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struct parsed_elf *pelf;
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const Elf64_Phdr *phdr;
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pelf = &ctx->pelf;
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phdr = ctx->phdr;
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shstrtab = buffer_get(pelf->strtabs[pelf->ehdr.e_shstrndx]);
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/*
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* Find all relocation sections that contain relocation entries
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* for sections that fall within the bounds of the segment. For
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* easier processing the pointer to the relocation array for the
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* sections that don't fall within the loadable program are NULL'd
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* out.
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*/
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for (i = 0; i < pelf->ehdr.e_shnum; i++) {
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Elf64_Shdr *shdr;
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Elf64_Word sh_info;
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const char *section_name;
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shdr = &pelf->shdr[i];
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/* Ignore non-relocation sections. */
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if (shdr->sh_type != SHT_RELA && shdr->sh_type != SHT_REL)
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continue;
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/* Obtain section which relocations apply. */
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sh_info = shdr->sh_info;
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shdr = &pelf->shdr[sh_info];
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section_name = &shstrtab[shdr->sh_name];
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DEBUG("Relocation section found for '%s' section.\n",
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section_name);
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/* Do not process relocations for debug sections. */
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if (strstr(section_name, ".debug") != NULL) {
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pelf->relocs[i] = NULL;
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continue;
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}
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/*
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* If relocations apply to a non program section ignore the
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* relocations for future processing.
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*/
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if (shdr->sh_type != SHT_PROGBITS) {
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pelf->relocs[i] = NULL;
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continue;
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}
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if (shdr->sh_addr < phdr->p_vaddr ||
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((shdr->sh_addr + shdr->sh_size) >
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(phdr->p_vaddr + phdr->p_memsz))) {
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ERROR("Relocations being applied to section %d not "
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"within segment region.\n", sh_info);
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return -1;
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}
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}
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return 0;
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}
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static int vaddr_cmp(const void *a, const void *b)
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{
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const Elf64_Addr *pa = a;
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const Elf64_Addr *pb = b;
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if (*pa < *pb)
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return -1;
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if (*pa > *pb)
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return 1;
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return 0;
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}
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int rmodule_collect_relocations(struct rmod_context *ctx,
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struct reloc_filter *f)
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{
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Elf64_Xword nrelocs;
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/*
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* The relocs array in the pelf should only contain relocations that
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* apply to the program. Count the number relocations. Then collect
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* them into the allocated buffer.
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*/
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if (for_each_reloc(ctx, f, 0))
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return -1;
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nrelocs = ctx->nrelocs;
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INFO("%" PRIu64 " relocations to be emitted.\n", nrelocs);
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if (!nrelocs)
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return 0;
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/* Reset the counter for indexing into the array. */
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ctx->nrelocs = 0;
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ctx->emitted_relocs = calloc(nrelocs, sizeof(Elf64_Addr));
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/* Write out the relocations into the emitted_relocs array. */
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if (for_each_reloc(ctx, f, 1))
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return -1;
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if (ctx->nrelocs != nrelocs) {
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ERROR("Mismatch counted and emitted relocations: %zu vs %zu.\n",
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(size_t)nrelocs, (size_t)ctx->nrelocs);
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return -1;
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}
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/* Sort the relocations by their address. */
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qsort(ctx->emitted_relocs, nrelocs, sizeof(Elf64_Addr), vaddr_cmp);
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return 0;
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}
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static int
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populate_sym(struct rmod_context *ctx, const char *sym_name, Elf64_Addr *addr,
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int nsyms, int optional)
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{
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int i;
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Elf64_Sym *syms;
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syms = ctx->pelf.syms;
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for (i = 0; i < nsyms; i++) {
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if (syms[i].st_name == 0)
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continue;
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if (strcmp(sym_name, &ctx->strtab[syms[i].st_name]))
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continue;
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DEBUG("%s -> 0x%llx\n", sym_name, (long long)syms[i].st_value);
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*addr = syms[i].st_value;
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return 0;
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}
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if (optional) {
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DEBUG("optional symbol '%s' not found.\n", sym_name);
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*addr = 0;
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return 0;
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}
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ERROR("symbol '%s' not found.\n", sym_name);
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return -1;
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}
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static int populate_rmodule_info(struct rmod_context *ctx)
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{
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int i;
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struct parsed_elf *pelf;
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Elf64_Ehdr *ehdr;
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int nsyms;
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pelf = &ctx->pelf;
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ehdr = &pelf->ehdr;
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/* Determine number of symbols. */
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nsyms = 0;
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for (i = 0; i < ehdr->e_shnum; i++) {
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if (pelf->shdr[i].sh_type != SHT_SYMTAB)
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continue;
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nsyms = pelf->shdr[i].sh_size / pelf->shdr[i].sh_entsize;
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break;
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}
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if (populate_sym(ctx, "_rmodule_params", &ctx->parameters_begin, nsyms, 1))
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return -1;
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if (populate_sym(ctx, "_ermodule_params", &ctx->parameters_end, nsyms, 1))
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return -1;
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if (populate_sym(ctx, "_bss", &ctx->bss_begin, nsyms, 0))
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return -1;
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if (populate_sym(ctx, "_ebss", &ctx->bss_end, nsyms, 0))
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return -1;
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return 0;
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}
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static int
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add_section(struct elf_writer *ew, struct buffer *data, const char *name,
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Elf64_Addr addr, Elf64_Word size)
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{
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Elf64_Shdr shdr;
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int ret;
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memset(&shdr, 0, sizeof(shdr));
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if (data != NULL) {
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shdr.sh_type = SHT_PROGBITS;
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shdr.sh_flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR;
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} else {
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shdr.sh_type = SHT_NOBITS;
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shdr.sh_flags = SHF_ALLOC;
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}
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shdr.sh_addr = addr;
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shdr.sh_offset = addr;
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shdr.sh_size = size;
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ret = elf_writer_add_section(ew, &shdr, data, name);
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if (ret)
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ERROR("Could not add '%s' section.\n", name);
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return ret;
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}
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static int
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write_elf(const struct rmod_context *ctx, const struct buffer *in,
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struct buffer *out)
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{
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int ret;
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int bit64;
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size_t loc;
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size_t rmod_data_size;
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struct elf_writer *ew;
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struct buffer rmod_data;
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struct buffer rmod_header;
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struct buffer program;
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struct buffer relocs;
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Elf64_Xword total_size;
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Elf64_Addr addr;
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Elf64_Ehdr ehdr;
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bit64 = ctx->pelf.ehdr.e_ident[EI_CLASS] == ELFCLASS64;
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/*
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* 3 sections will be added to the ELF file.
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* +------------------+
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* | rmodule header |
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* +------------------+
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* | program |
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* +------------------+
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* | relocations |
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* +------------------+
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*/
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/* Create buffer for header and relocations. */
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rmod_data_size = sizeof(struct rmodule_header);
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if (bit64)
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rmod_data_size += ctx->nrelocs * sizeof(Elf64_Addr);
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else
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rmod_data_size += ctx->nrelocs * sizeof(Elf32_Addr);
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if (buffer_create(&rmod_data, rmod_data_size, "rmod"))
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return -1;
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buffer_splice(&rmod_header, &rmod_data,
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0, sizeof(struct rmodule_header));
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buffer_clone(&relocs, &rmod_data);
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buffer_seek(&relocs, sizeof(struct rmodule_header));
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/* Reset current location. */
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buffer_set_size(&rmod_header, 0);
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buffer_set_size(&relocs, 0);
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/* Program contents. */
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buffer_splice(&program, in, ctx->phdr->p_offset, ctx->phdr->p_filesz);
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/* Create ELF writer. Set entry point to 0 to match section offsets. */
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memcpy(&ehdr, &ctx->pelf.ehdr, sizeof(ehdr));
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ehdr.e_entry = 0;
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ew = elf_writer_init(&ehdr);
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if (ew == NULL) {
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ERROR("Failed to create ELF writer.\n");
|
|
buffer_delete(&rmod_data);
|
|
return -1;
|
|
}
|
|
|
|
/* Write out rmodule_header. */
|
|
ctx->xdr->put16(&rmod_header, RMODULE_MAGIC);
|
|
ctx->xdr->put8(&rmod_header, RMODULE_VERSION_1);
|
|
ctx->xdr->put8(&rmod_header, 0);
|
|
/* payload_begin_offset */
|
|
loc = sizeof(struct rmodule_header);
|
|
ctx->xdr->put32(&rmod_header, loc);
|
|
/* payload_end_offset */
|
|
loc += ctx->phdr->p_filesz;
|
|
ctx->xdr->put32(&rmod_header, loc);
|
|
/* relocations_begin_offset */
|
|
ctx->xdr->put32(&rmod_header, loc);
|
|
/* relocations_end_offset */
|
|
if (bit64)
|
|
loc += ctx->nrelocs * sizeof(Elf64_Addr);
|
|
else
|
|
loc += ctx->nrelocs * sizeof(Elf32_Addr);
|
|
ctx->xdr->put32(&rmod_header, loc);
|
|
/* module_link_start_address */
|
|
ctx->xdr->put32(&rmod_header, ctx->phdr->p_vaddr);
|
|
/* module_program_size */
|
|
ctx->xdr->put32(&rmod_header, ctx->phdr->p_memsz);
|
|
/* module_entry_point */
|
|
ctx->xdr->put32(&rmod_header, ctx->pelf.ehdr.e_entry);
|
|
/* parameters_begin */
|
|
ctx->xdr->put32(&rmod_header, ctx->parameters_begin);
|
|
/* parameters_end */
|
|
ctx->xdr->put32(&rmod_header, ctx->parameters_end);
|
|
/* bss_begin */
|
|
ctx->xdr->put32(&rmod_header, ctx->bss_begin);
|
|
/* bss_end */
|
|
ctx->xdr->put32(&rmod_header, ctx->bss_end);
|
|
/* padding[4] */
|
|
ctx->xdr->put32(&rmod_header, 0);
|
|
ctx->xdr->put32(&rmod_header, 0);
|
|
ctx->xdr->put32(&rmod_header, 0);
|
|
ctx->xdr->put32(&rmod_header, 0);
|
|
|
|
/* Write the relocations. */
|
|
for (unsigned i = 0; i < ctx->nrelocs; i++) {
|
|
if (bit64)
|
|
ctx->xdr->put64(&relocs, ctx->emitted_relocs[i]);
|
|
else
|
|
ctx->xdr->put32(&relocs, ctx->emitted_relocs[i]);
|
|
}
|
|
|
|
total_size = 0;
|
|
addr = 0;
|
|
|
|
/*
|
|
* There are 2 cases to deal with. The program has a large NOBITS
|
|
* section and the relocations can fit entirely within occupied memory
|
|
* region for the program. The other is that the relocations increase
|
|
* the memory footprint of the program if it was loaded directly into
|
|
* the region it would run. The rmodule header is a fixed cost that
|
|
* is considered a part of the program.
|
|
*/
|
|
total_size += buffer_size(&rmod_header);
|
|
if (buffer_size(&relocs) + ctx->phdr->p_filesz > ctx->phdr->p_memsz) {
|
|
total_size += buffer_size(&relocs);
|
|
total_size += ctx->phdr->p_filesz;
|
|
} else {
|
|
total_size += ctx->phdr->p_memsz;
|
|
}
|
|
|
|
ret = add_section(ew, &rmod_header, ".header", addr,
|
|
buffer_size(&rmod_header));
|
|
if (ret < 0)
|
|
goto out;
|
|
addr += buffer_size(&rmod_header);
|
|
|
|
ret = add_section(ew, &program, ".program", addr, ctx->phdr->p_filesz);
|
|
if (ret < 0)
|
|
goto out;
|
|
addr += ctx->phdr->p_filesz;
|
|
|
|
if (ctx->nrelocs) {
|
|
ret = add_section(ew, &relocs, ".relocs", addr,
|
|
buffer_size(&relocs));
|
|
if (ret < 0)
|
|
goto out;
|
|
addr += buffer_size(&relocs);
|
|
}
|
|
|
|
if (total_size != addr) {
|
|
ret = add_section(ew, NULL, ".empty", addr, total_size - addr);
|
|
if (ret < 0)
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Ensure last section has a memory usage that meets the required
|
|
* total size of the program in memory.
|
|
*/
|
|
|
|
ret = elf_writer_serialize(ew, out);
|
|
if (ret < 0)
|
|
ERROR("Failed to serialize ELF to buffer.\n");
|
|
|
|
out:
|
|
buffer_delete(&rmod_data);
|
|
elf_writer_destroy(ew);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int rmodule_init(struct rmod_context *ctx, const struct buffer *elfin)
|
|
{
|
|
struct parsed_elf *pelf;
|
|
size_t i;
|
|
int ret;
|
|
|
|
ret = -1;
|
|
memset(ctx, 0, sizeof(*ctx));
|
|
pelf = &ctx->pelf;
|
|
|
|
if (parse_elf(elfin, pelf, ELF_PARSE_ALL)) {
|
|
ERROR("Couldn't parse ELF!\n");
|
|
return -1;
|
|
}
|
|
|
|
/* Only allow executables to be turned into rmodules. */
|
|
if (pelf->ehdr.e_type != ET_EXEC) {
|
|
ERROR("ELF is not an executable: %u.\n", pelf->ehdr.e_type);
|
|
goto out;
|
|
}
|
|
|
|
/* Determine if architecture is supported. */
|
|
for (i = 0; i < ARRAY_SIZE(reloc_ops); i++) {
|
|
if (reloc_ops[i].arch == pelf->ehdr.e_machine) {
|
|
ctx->ops = &reloc_ops[i];
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (ctx->ops == NULL) {
|
|
ERROR("ELF is unsupported arch: %u.\n", pelf->ehdr.e_machine);
|
|
goto out;
|
|
}
|
|
|
|
/* Set the endian ops. */
|
|
if (ctx->pelf.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
|
|
ctx->xdr = &xdr_be;
|
|
else
|
|
ctx->xdr = &xdr_le;
|
|
|
|
/* Obtain the string table. */
|
|
for (i = 0; i < pelf->ehdr.e_shnum; i++) {
|
|
if (pelf->strtabs[i] == NULL)
|
|
continue;
|
|
/* Don't use the section headers' string table. */
|
|
if (i == pelf->ehdr.e_shstrndx)
|
|
continue;
|
|
ctx->strtab = buffer_get(pelf->strtabs[i]);
|
|
break;
|
|
}
|
|
|
|
if (ctx->strtab == NULL) {
|
|
ERROR("No string table found.\n");
|
|
return -1;
|
|
}
|
|
|
|
if (find_program_segment(ctx))
|
|
goto out;
|
|
|
|
if (filter_relocation_sections(ctx))
|
|
goto out;
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void rmodule_cleanup(struct rmod_context *ctx)
|
|
{
|
|
free(ctx->emitted_relocs);
|
|
parsed_elf_destroy(&ctx->pelf);
|
|
}
|
|
|
|
int rmodule_create(const struct buffer *elfin, struct buffer *elfout)
|
|
{
|
|
struct rmod_context ctx;
|
|
int ret = -1;
|
|
|
|
if (rmodule_init(&ctx, elfin))
|
|
goto out;
|
|
|
|
if (rmodule_collect_relocations(&ctx, NULL))
|
|
goto out;
|
|
|
|
if (populate_rmodule_info(&ctx))
|
|
goto out;
|
|
|
|
if (write_elf(&ctx, elfin, elfout))
|
|
goto out;
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
rmodule_cleanup(&ctx);
|
|
return ret;
|
|
}
|
|
|
|
static void rmod_deserialize(struct rmodule_header *rmod, struct buffer *buff,
|
|
struct xdr *xdr)
|
|
{
|
|
rmod->magic = xdr->get16(buff);
|
|
rmod->version = xdr->get8(buff);
|
|
rmod->type = xdr->get8(buff);
|
|
rmod->payload_begin_offset = xdr->get32(buff);
|
|
rmod->payload_end_offset = xdr->get32(buff);
|
|
rmod->relocations_begin_offset = xdr->get32(buff);
|
|
rmod->relocations_end_offset = xdr->get32(buff);
|
|
rmod->module_link_start_address = xdr->get32(buff);
|
|
rmod->module_program_size = xdr->get32(buff);
|
|
rmod->module_entry_point = xdr->get32(buff);
|
|
rmod->parameters_begin = xdr->get32(buff);
|
|
rmod->parameters_end = xdr->get32(buff);
|
|
rmod->bss_begin = xdr->get32(buff);
|
|
rmod->bss_end = xdr->get32(buff);
|
|
rmod->padding[0] = xdr->get32(buff);
|
|
rmod->padding[1] = xdr->get32(buff);
|
|
rmod->padding[2] = xdr->get32(buff);
|
|
rmod->padding[3] = xdr->get32(buff);
|
|
}
|
|
|
|
int rmodule_stage_to_elf(Elf64_Ehdr *ehdr, struct buffer *buff)
|
|
{
|
|
struct buffer reader;
|
|
struct buffer elf_out;
|
|
struct rmodule_header rmod;
|
|
struct xdr *xdr;
|
|
struct elf_writer *ew;
|
|
Elf64_Shdr shdr;
|
|
int bit64;
|
|
size_t payload_sz;
|
|
const char *section_name = ".program";
|
|
const size_t input_sz = buffer_size(buff);
|
|
|
|
buffer_clone(&reader, buff);
|
|
|
|
xdr = (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) ? &xdr_be : &xdr_le;
|
|
bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
|
|
|
|
rmod_deserialize(&rmod, &reader, xdr);
|
|
|
|
/* Indicate that file is not an rmodule if initial checks fail. */
|
|
if (rmod.magic != RMODULE_MAGIC)
|
|
return 1;
|
|
if (rmod.version != RMODULE_VERSION_1)
|
|
return 1;
|
|
|
|
if (rmod.payload_begin_offset > input_sz ||
|
|
rmod.payload_end_offset > input_sz ||
|
|
rmod.relocations_begin_offset > input_sz ||
|
|
rmod.relocations_end_offset > input_sz) {
|
|
ERROR("Rmodule fields out of bounds.\n");
|
|
return -1;
|
|
}
|
|
|
|
ehdr->e_entry = rmod.module_entry_point;
|
|
ew = elf_writer_init(ehdr);
|
|
|
|
if (ew == NULL)
|
|
return -1;
|
|
|
|
payload_sz = rmod.payload_end_offset - rmod.payload_begin_offset;
|
|
memset(&shdr, 0, sizeof(shdr));
|
|
shdr.sh_type = SHT_PROGBITS;
|
|
shdr.sh_flags = SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR;
|
|
shdr.sh_addr = rmod.module_link_start_address;
|
|
shdr.sh_size = payload_sz;
|
|
buffer_splice(&reader, buff, rmod.payload_begin_offset, payload_sz);
|
|
|
|
if (elf_writer_add_section(ew, &shdr, &reader, section_name)) {
|
|
ERROR("Unable to add ELF section: %s\n", section_name);
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
|
|
if (payload_sz != rmod.module_program_size) {
|
|
struct buffer b;
|
|
|
|
buffer_init(&b, NULL, NULL, 0);
|
|
memset(&shdr, 0, sizeof(shdr));
|
|
shdr.sh_type = SHT_NOBITS;
|
|
shdr.sh_flags = SHF_WRITE | SHF_ALLOC;
|
|
shdr.sh_addr = rmod.module_link_start_address + payload_sz;
|
|
shdr.sh_size = rmod.module_program_size - payload_sz;
|
|
if (elf_writer_add_section(ew, &shdr, &b, ".empty")) {
|
|
ERROR("Unable to add ELF section: .empty\n");
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* Provide a section symbol so the relcoations can reference that. */
|
|
if (elf_writer_add_symbol(ew, section_name, section_name, shdr.sh_addr,
|
|
0, STB_LOCAL, STT_SECTION)) {
|
|
ERROR("Unable to add section symbol to ELF.\n");
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
|
|
/* Add symbols for the parameters if they are non-zero. */
|
|
if (rmod.parameters_begin != rmod.parameters_end) {
|
|
int ret = 0;
|
|
|
|
ret |= elf_writer_add_symbol(ew, "_rmodule_params",
|
|
section_name,
|
|
rmod.parameters_begin, 0,
|
|
STB_GLOBAL, STT_NOTYPE);
|
|
ret |= elf_writer_add_symbol(ew, "_ermodule_params",
|
|
section_name,
|
|
rmod.parameters_end, 0,
|
|
STB_GLOBAL, STT_NOTYPE);
|
|
|
|
if (ret != 0) {
|
|
ERROR("Unable to add module params symbols to ELF\n");
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
if (elf_writer_add_symbol(ew, "_bss", section_name, rmod.bss_begin, 0,
|
|
STB_GLOBAL, STT_NOTYPE) ||
|
|
elf_writer_add_symbol(ew, "_ebss", section_name, rmod.bss_end, 0,
|
|
STB_GLOBAL, STT_NOTYPE)) {
|
|
ERROR("Unable to add bss symbols to ELF\n");
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
|
|
ssize_t relocs_sz = rmod.relocations_end_offset;
|
|
relocs_sz -= rmod.relocations_begin_offset;
|
|
buffer_splice(&reader, buff, rmod.relocations_begin_offset, relocs_sz);
|
|
while (relocs_sz > 0) {
|
|
Elf64_Addr addr;
|
|
|
|
if (bit64) {
|
|
relocs_sz -= sizeof(Elf64_Addr);
|
|
addr = xdr->get64(&reader);
|
|
} else {
|
|
relocs_sz -= sizeof(Elf32_Addr);
|
|
addr = xdr->get32(&reader);
|
|
}
|
|
|
|
/* Skip any relocations that are below the link address. */
|
|
if (addr < rmod.module_link_start_address)
|
|
continue;
|
|
|
|
if (elf_writer_add_rel(ew, section_name, addr)) {
|
|
ERROR("Relocation addition failure.\n");
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
if (elf_writer_serialize(ew, &elf_out)) {
|
|
ERROR("ELF writer serialize failure.\n");
|
|
elf_writer_destroy(ew);
|
|
return -1;
|
|
}
|
|
|
|
elf_writer_destroy(ew);
|
|
|
|
/* Flip buffer with the created ELF one. */
|
|
buffer_delete(buff);
|
|
*buff = elf_out;
|
|
|
|
return 0;
|
|
}
|