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         va_start(args, fmt);
  31         if (debug_en)
  32                 vprintf(fmt, args);
  33 }
  34
  35 static bool supported_rela(Elf64_Rela *rela)
  36 {
  37         uint64_t mask = 0xffffffffULL; /* would be different on 32-bit */
  38         uint32_t type = rela->r_info & mask;
  39
  40         switch (type) {
  41 #ifdef R_AARCH64_RELATIVE
  42         case R_AARCH64_RELATIVE:
  43                 return true;
  44 #endif
  45         default:
  46                 fprintf(stderr, "warning: unsupported relocation type %"
  47                                 PRIu32 " at %" PRIx64 "\n",
  48                         type, rela->r_offset);
  49
  50                 return false;
  51         }
  52 }
  53
  54 static bool read_num(const char *str, uint64_t *num)
  55 {
  56         char *endptr;
  57         *num = strtoull(str, &endptr, 16);
  58         return str[0] && !endptr[0];
  59 }
  60
  61 int main(int argc, char **argv)
  62 {
  63         FILE *f;
  64         int i, num;
  65         uint64_t rela_start, rela_end, text_base;
  66
  67         if (argc != 5) {
  68                 fprintf(stderr, "Statically apply ELF rela relocations\n");
  69                 fprintf(stderr, "Usage: %s <bin file> <text base> " \
  70                                 "<rela start> <rela end>\n", argv[0]);
  71                 fprintf(stderr, "All numbers in hex.\n");
  72                 return 1;
  73         }
  74
  75         f = fopen(argv[1], "r+b");
  76         if (!f) {
  77                 fprintf(stderr, "%s: Cannot open %s: %s\n",
  78                         argv[0], argv[1], strerror(errno));
  79                 return 2;
  80         }
  81
  82         if (!read_num(argv[2], &text_base) ||
  83             !read_num(argv[3], &rela_start) ||
  84             !read_num(argv[4], &rela_end)) {
  85                 fprintf(stderr, "%s: bad number\n", argv[0]);
  86                 return 3;
  87         }
  88
  89         if (rela_start > rela_end || rela_start < text_base ||
  90             (rela_end - rela_start) % sizeof(Elf64_Rela)) {
  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         num = (rela_end - rela_start) / sizeof(Elf64_Rela);
  99
 100         for (i = 0; i < num; i++) {
 101                 Elf64_Rela rela, swrela;
 102                 uint64_t pos = rela_start + sizeof(Elf64_Rela) * i;
 103                 uint64_t addr;
 104
 105                 if (fseek(f, pos, SEEK_SET) < 0) {
 106                         fprintf(stderr, "%s: %s: seek to %" PRIx64
 107                                         " failed: %s\n",
 108                                 argv[0], argv[1], pos, strerror(errno));
 109                 }
 110
 111                 if (fread(&rela, sizeof(rela), 1, f) != 1) {
 112                         fprintf(stderr, "%s: %s: read rela failed at %"
 113                                         PRIx64 "\n",
 114                                 argv[0], argv[1], pos);
 115                         return 4;
 116                 }
 117
 118                 swrela.r_offset = cpu_to_le64(rela.r_offset);
 119                 swrela.r_info = cpu_to_le64(rela.r_info);
 120                 swrela.r_addend = cpu_to_le64(rela.r_addend);
 121
 122                 if (!supported_rela(&swrela))
 123                         continue;
 124
 125                 debug("Rela %" PRIx64 " %" PRIu64 " %" PRIx64 "\n",
 126                       swrela.r_offset, swrela.r_info, swrela.r_addend);
 127
 128                 if (swrela.r_offset < text_base) {
 129                         fprintf(stderr, "%s: %s: bad rela at %" PRIx64 "\n",
 130                                 argv[0], argv[1], pos);
 131                         return 4;
 132                 }
 133
 134                 addr = swrela.r_offset - text_base;
 135
 136                 if (fseek(f, addr, SEEK_SET) < 0) {
 137                         fprintf(stderr, "%s: %s: seek to %"
 138                                         PRIx64 " failed: %s\n",
 139                                 argv[0], argv[1], addr, strerror(errno));
 140                 }
 141
 142                 if (fwrite(&rela.r_addend, sizeof(rela.r_addend), 1, f) != 1) {
 143                         fprintf(stderr, "%s: %s: write failed at %" PRIx64 "\n",
 144                                 argv[0], argv[1], addr);
 145                         return 4;
 146                 }
 147         }
 148
 149         if (fclose(f) < 0) {
 150                 fprintf(stderr, "%s: %s: close failed: %s\n",
 151                         argv[0], argv[1], strerror(errno));
 152                 return 4;
 153         }
 154
 155         return 0;
 156 }