1 /* Generate checksums of executables for PCH validation 2 Copyright (C) 2005-2018 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #include "bconfig.h" 21 #include "system.h" 22 #include "md5.h" 23 24 static void 25 usage (void) 26 { 27 fputs ("Usage: genchecksums <filename> ...\n", stderr); 28 } 29 30 /* Important: BLOCKSIZE must be a multiple of 64. */ 31 #define BLOCKSIZE 4096 32 33 static void 34 dosum (struct md5_ctx *ctx, const char *file) 35 { 36 FILE *f; 37 char buffer[BLOCKSIZE + 72]; 38 size_t sum; 39 40 f = fopen (file, "rb"); 41 if (!f) 42 { 43 fprintf (stderr, "opening %s: %s\n", file, xstrerror (errno)); 44 exit (1); 45 } 46 47 /* Some executable formats have timestamps in the first 16 bytes, yuck. */ 48 if (fseek (f, 16, SEEK_SET) != 0) 49 { 50 fprintf (stderr, "seeking in %s: %s\n", file, xstrerror (errno)); 51 exit (1); 52 } 53 54 /* Iterate over full file contents. */ 55 while (1) 56 { 57 /* We read the file in blocks of BLOCKSIZE bytes. One call of the 58 computation function processes the whole buffer so that with the 59 next round of the loop another block can be read. */ 60 size_t n; 61 sum = 0; 62 63 /* Read block. Take care for partial reads. */ 64 do 65 { 66 n = fread (buffer + sum, 1, BLOCKSIZE - sum, f); 67 68 sum += n; 69 } 70 while (sum < BLOCKSIZE && n != 0); 71 if (n == 0 && ferror (f)) 72 exit (1); 73 74 /* If end of file is reached, end the loop. */ 75 if (n == 0) 76 break; 77 78 /* Process buffer with BLOCKSIZE bytes. Note that 79 BLOCKSIZE % 64 == 0 80 */ 81 md5_process_block (buffer, BLOCKSIZE, ctx); 82 } 83 84 /* Add the last bytes if necessary. */ 85 if (sum > 0) 86 md5_process_bytes (buffer, sum, ctx); 87 88 if (fclose (f) != 0) 89 { 90 fprintf (stderr, "reading %s: %s\n", file, xstrerror (errno)); 91 exit (1); 92 } 93 } 94 95 int 96 main (int argc, char ** argv) 97 { 98 struct md5_ctx ctx; 99 unsigned char result[16]; 100 int i; 101 102 if (argc < 2) 103 { 104 usage (); 105 return 1; 106 } 107 108 md5_init_ctx (&ctx); 109 for (i = 1; i < argc; i++) 110 dosum (&ctx, argv[i]); 111 md5_finish_ctx (&ctx, result); 112 113 puts ("#include \"config.h\""); 114 puts ("#include \"system.h\""); 115 fputs ("EXPORTED_CONST unsigned char executable_checksum[16] = { ", stdout); 116 for (i = 0; i < 16; i++) 117 printf ("0x%02x%s", result[i], i == 15 ? " };\n" : ", "); 118 119 return 0; 120 } 121