tools/relocate-rela.c

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