LXR uboot/tools/relocate-rela.c

   1// SPDX-License-Identifier: GPL-2.0+ OR BSD-2-Clause
   2/*
   3 * Copyright 2013 Freescale Semiconductor, Inc.
   4 *
   5 * 64-bit and little-endian target only until we need to support a different
   6 * arch that needs this.
   7 */
   8
   9#include <elf.h>
  10#include <errno.h>
  11#include <inttypes.h>
  12#include <stdarg.h>
  13#include <stdbool.h>
  14#include <stdio.h>
  15#include <stdlib.h>
  16#include <string.h>
  17#include "compiler.h"
  18
  19#ifndef R_AARCH64_RELATIVE
  20#define R_AARCH64_RELATIVE      1027
  21#endif
  22
  23static const bool debug_en;
  24
  25static void debug(const char *fmt, ...)
  26{
  27        va_list args;
  28
  29        if (debug_en) {
  30                va_start(args, fmt);
  31                vprintf(fmt, args);
  32                va_end(args);
  33        }
  34}
  35
  36static bool supported_rela(Elf64_Rela *rela)
  37{
  38        uint64_t mask = 0xffffffffULL; /* would be different on 32-bit */
  39        uint32_t type = rela->r_info & mask;
  40
  41        switch (type) {
  42#ifdef R_AARCH64_RELATIVE
  43        case R_AARCH64_RELATIVE:
  44                return true;
  45#endif
  46        default:
  47                fprintf(stderr, "warning: unsupported relocation type %"
  48                                PRIu32 " at %" PRIx64 "\n",
  49                        type, rela->r_offset);
  50
  51                return false;
  52        }
  53}
  54
  55static bool read_num(const char *str, uint64_t *num)
  56{
  57        char *endptr;
  58        *num = strtoull(str, &endptr, 16);
  59        return str[0] && !endptr[0];
  60}
  61
  62int main(int argc, char **argv)
  63{
  64        FILE *f;
  65        int i, num;
  66        uint64_t rela_start, rela_end, text_base, file_size;
  67
  68        if (argc != 5) {
  69                fprintf(stderr, "Statically apply ELF rela relocations\n");
  70                fprintf(stderr, "Usage: %s <bin file> <text base> " \
  71                                "<rela start> <rela end>\n", argv[0]);
  72                fprintf(stderr, "All numbers in hex.\n");
  73                return 1;
  74        }
  75
  76        f = fopen(argv[1], "r+b");
  77        if (!f) {
  78                fprintf(stderr, "%s: Cannot open %s: %s\n",
  79                        argv[0], argv[1], strerror(errno));
  80                return 2;
  81        }
  82
  83        if (!read_num(argv[2], &text_base) ||
  84            !read_num(argv[3], &rela_start) ||
  85            !read_num(argv[4], &rela_end)) {
  86                fprintf(stderr, "%s: bad number\n", argv[0]);
  87                return 3;
  88        }
  89
  90        if (rela_start > rela_end || rela_start < text_base) {
  91                fprintf(stderr, "%s: bad rela bounds\n", argv[0]);
  92                return 3;
  93        }
  94
  95        rela_start -= text_base;
  96        rela_end -= text_base;
  97
  98        fseek(f, 0, SEEK_END);
  99        file_size = ftell(f);
 100        rewind(f);
 101
 102        if (rela_end > file_size) {
 103                // Most likely compiler inserted some section that didn't get
 104                // objcopy-ed into the final binary
 105                rela_end = file_size;
 106        }
 107
 108        if ((rela_end - rela_start) % sizeof(Elf64_Rela)) {
 109                fprintf(stderr, "%s: rela size isn't a multiple of Elf64_Rela\n", argv[0]);
 110                return 3;
 111        }
 112
 113        num = (rela_end - rela_start) / sizeof(Elf64_Rela);
 114
 115        for (i = 0; i < num; i++) {
 116                Elf64_Rela rela, swrela;
 117                uint64_t pos = rela_start + sizeof(Elf64_Rela) * i;
 118                uint64_t addr;
 119
 120                if (fseek(f, pos, SEEK_SET) < 0) {
 121                        fprintf(stderr, "%s: %s: seek to %" PRIx64
 122                                        " failed: %s\n",
 123                                argv[0], argv[1], pos, strerror(errno));
 124                }
 125
 126                if (fread(&rela, sizeof(rela), 1, f) != 1) {
 127                        fprintf(stderr, "%s: %s: read rela failed at %"
 128                                        PRIx64 "\n",
 129                                argv[0], argv[1], pos);
 130                        return 4;
 131                }
 132
 133                swrela.r_offset = cpu_to_le64(rela.r_offset);
 134                swrela.r_info = cpu_to_le64(rela.r_info);
 135                swrela.r_addend = cpu_to_le64(rela.r_addend);
 136
 137                if (!supported_rela(&swrela))
 138                        continue;
 139
 140                debug("Rela %" PRIx64 " %" PRIu64 " %" PRIx64 "\n",
 141                      swrela.r_offset, swrela.r_info, swrela.r_addend);
 142
 143                if (swrela.r_offset < text_base) {
 144                        fprintf(stderr, "%s: %s: bad rela at %" PRIx64 "\n",
 145                                argv[0], argv[1], pos);
 146                        return 4;
 147                }
 148
 149                addr = swrela.r_offset - text_base;
 150
 151                if (fseek(f, addr, SEEK_SET) < 0) {
 152                        fprintf(stderr, "%s: %s: seek to %"
 153                                        PRIx64 " failed: %s\n",
 154                                argv[0], argv[1], addr, strerror(errno));
 155                }
 156
 157                if (fwrite(&rela.r_addend, sizeof(rela.r_addend), 1, f) != 1) {
 158                        fprintf(stderr, "%s: %s: write failed at %" PRIx64 "\n",
 159                                argv[0], argv[1], addr);
 160                        return 4;
 161                }
 162        }
 163
 164        if (fclose(f) < 0) {
 165                fprintf(stderr, "%s: %s: close failed: %s\n",
 166                        argv[0], argv[1], strerror(errno));
 167                return 4;
 168        }
 169
 170        return 0;
 171}
 172