ndisasm.c

   1 /* ndisasm.c   the Netwide Disassembler main module
   2  *
   3  * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
   4  * Julian Hall. All rights reserved. The software is
   5  * redistributable under the licence given in the file "Licence"
   6  * distributed in the NASM archive.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <ctype.h>
  13 #include <errno.h>
  14
  15 #include "insns.h"
  16 #include "nasm.h"
  17 #include "nasmlib.h"
  18 #include "sync.h"
  19 #include "disasm.h"
  20
  21 #define BPL 8                          /* bytes per line of hex dump */
  22
  23 static const char *help =
  24 "usage: ndisasm [-a] [-i] [-h] [-r] [-u] [-b bits] [-o origin] [-s sync...]\n"
  25 "               [-e bytes] [-k start,bytes] [-p vendor] file\n"
  26 "   -a or -i activates auto (intelligent) sync\n"
  27 "   -u sets USE32 (32-bit mode)\n"
  28 "   -b 16 or -b 32 sets number of bits too\n"
  29 "   -h displays this text\n"
  30 "   -r displays the version number\n"
  31 "   -e skips <bytes> bytes of header\n"
  32 "   -k avoids disassembling <bytes> bytes from position <start>\n"
  33 "   -p selects the preferred vendor instruction set (intel, amd, cyrix, idt)\n";
  34
  35 static void output_ins (unsigned long, unsigned char *, int, char *);
  36 static void skip (unsigned long dist, FILE *fp);
  37
  38 int main(int argc, char **argv)
  39 {
  40     unsigned char buffer[INSN_MAX * 2], *p, *q;
  41     char outbuf[256];
  42     char *pname = *argv;
  43     char *filename = NULL;
  44     unsigned long nextsync, synclen, initskip = 0L;
  45     int lenread;
  46     long lendis;
  47     int autosync = FALSE;
  48     int bits = 16;
  49     int eof = FALSE;
  50     unsigned long prefer = 0;
  51     int rn_error;
  52     long offset;
  53     FILE *fp;
  54
  55     offset = 0;
  56     init_sync();
  57
  58     while (--argc) {
  59         char *v, *vv, *p = *++argv;
  60         if (*p == '-' && p[1]) {
  61             p++;
  62             while (*p) switch (tolower(*p)) {
  63               case 'a':                /* auto or intelligent sync */
  64               case 'i':
  65                 autosync = TRUE;
  66                 p++;
  67                 break;
  68               case 'h':
  69                 fprintf(stderr, help);
  70                 return 0;
  71               case 'r':
  72                 fprintf(stderr, "NDISASM version " NASM_VER "\n");
  73                 return 0;
  74               case 'u':                /* USE32 */
  75                 bits = 32;
  76                 p++;
  77                 break;
  78               case 'b':                /* bits */
  79                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
  80                 if (!v) {
  81                     fprintf(stderr, "%s: `-b' requires an argument\n", pname);
  82                     return 1;
  83                 }
  84                 if (!strcmp(v, "16"))
  85                     bits = 16;
  86                 else if (!strcmp(v, "32"))
  87                     bits = 32;
  88                 else {
  89                     fprintf(stderr, "%s: argument to `-b' should"
  90                             " be `16' or `32'\n", pname);
  91                 }
  92                 p = "";                /* force to next argument */
  93                 break;
  94               case 'o':                /* origin */
  95                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
  96                 if (!v) {
  97                     fprintf(stderr, "%s: `-o' requires an argument\n", pname);
  98                     return 1;
  99                 }
 100                 offset = readnum (v, &rn_error);
 101                 if (rn_error) {
 102                     fprintf(stderr, "%s: `-o' requires a numeric argument\n",
 103                             pname);
 104                     return 1;
 105                 }
 106                 p = "";                /* force to next argument */
 107                 break;
 108               case 's':                /* sync point */
 109                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 110                 if (!v) {
 111                     fprintf(stderr, "%s: `-s' requires an argument\n", pname);
 112                     return 1;
 113                 }
 114                 add_sync (readnum (v, &rn_error), 0L);
 115                 if (rn_error) {
 116                     fprintf(stderr, "%s: `-s' requires a numeric argument\n",
 117                             pname);
 118                     return 1;
 119                 }
 120                 p = "";                /* force to next argument */
 121                 break;
 122               case 'e':                /* skip a header */
 123                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 124                 if (!v) {
 125                     fprintf(stderr, "%s: `-e' requires an argument\n", pname);
 126                     return 1;
 127                 }
 128                 initskip = readnum (v, &rn_error);
 129                 if (rn_error) {
 130                     fprintf(stderr, "%s: `-e' requires a numeric argument\n",
 131                             pname);
 132                     return 1;
 133                 }
 134                 p = "";                /* force to next argument */
 135                 break;
 136               case 'k':                /* skip a region */
 137                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 138                 if (!v) {
 139                     fprintf(stderr, "%s: `-k' requires an argument\n", pname);
 140                     return 1;
 141                 }
 142                 vv = strchr(v, ',');
 143                 if (!vv) {
 144                     fprintf(stderr, "%s: `-k' requires two numbers separated"
 145                             " by a comma\n", pname);
 146                     return 1;
 147                 }
 148                 *vv++ = '\0';
 149                 nextsync = readnum (v, &rn_error);
 150                 if (rn_error) {
 151                     fprintf(stderr, "%s: `-k' requires numeric arguments\n",
 152                             pname);
 153                     return 1;
 154                 }
 155                 synclen = readnum (vv, &rn_error);
 156                 if (rn_error) {
 157                     fprintf(stderr, "%s: `-k' requires numeric arguments\n",
 158                             pname);
 159                     return 1;
 160                 }
 161                 add_sync (nextsync, synclen);
 162                 p = "";                /* force to next argument */
 163                 break;
 164             case 'p':                  /* preferred vendor */
 165                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 166                 if (!v) {
 167                     fprintf(stderr, "%s: `-p' requires an argument\n", pname);
 168                     return 1;
 169                 }
 170                 if ( !strcmp(v, "intel") ) {
 171                   prefer = 0;   /* Default */
 172                 } else if ( !strcmp(v, "amd") ) {
 173                   prefer = IF_AMD|IF_3DNOW;
 174                 } else if ( !strcmp(v, "cyrix") ) {
 175                   prefer = IF_CYRIX|IF_3DNOW;
 176                 } else if ( !strcmp(v, "idt") || !strcmp(v, "centaur") ||
 177                             !strcmp(v, "winchip") ) {
 178                   prefer = IF_3DNOW;
 179                 } else {
 180                   fprintf(stderr, "%s: unknown vendor `%s' specified with `-p'\n", pname, v);
 181                   return 1;
 182                 }
 183                 p = "";                /* force to next argument */
 184                 break;
 185             default:                                                    /*bf*/
 186                 fprintf(stderr, "%s: unrecognised option `-%c'\n",
 187                         pname, *p);
 188                 return 1;
 189             }
 190         } else if (!filename) {
 191             filename = p;
 192         } else {
 193             fprintf(stderr, "%s: more than one filename specified\n", pname);
 194             return 1;
 195         }
 196     }
 197
 198     if (!filename) {
 199         fprintf(stderr, help, pname);
 200         return 0;
 201     }
 202
 203     if (strcmp(filename, "-")) {
 204         fp = fopen(filename, "rb");
 205         if (!fp) {
 206             fprintf(stderr, "%s: unable to open `%s': %s\n",
 207                     pname, filename, strerror(errno));
 208             return 1;
 209         }
 210     } else
 211         fp = stdin;
 212
 213     if (initskip > 0)
 214         skip (initskip, fp);
 215
 216     /*
 217      * This main loop is really horrible, and wants rewriting with
 218      * an axe. It'll stay the way it is for a while though, until I
 219      * find the energy...
 220      */
 221
 222     p = q = buffer;
 223     nextsync = next_sync (offset, &synclen);
 224     do {
 225         unsigned long to_read = buffer+sizeof(buffer)-p;
 226         if (to_read > nextsync-offset-(p-q))
 227             to_read = nextsync-offset-(p-q);
 228         if (to_read) {
 229             lenread = fread (p, 1, to_read, fp);
 230             if (lenread == 0)
 231                 eof = TRUE;            /* help along systems with bad feof */
 232         } else
 233             lenread = 0;
 234         p += lenread;
 235         if ((unsigned long)offset == nextsync) {
 236             if (synclen) {
 237                 printf("%08lX  skipping 0x%lX bytes\n", offset, synclen);
 238                 offset += synclen;
 239                 skip (synclen, fp);
 240             }
 241             p = q = buffer;
 242             nextsync = next_sync (offset, &synclen);
 243         }
 244         while (p > q && (p - q >= INSN_MAX || lenread == 0)) {
 245             lendis = disasm (q, outbuf, bits, offset, autosync, prefer);
 246             if (!lendis || lendis > (p - q) ||
 247                 (unsigned long)lendis > nextsync-offset)
 248                 lendis = eatbyte (q, outbuf);
 249             output_ins (offset, q, lendis, outbuf);
 250             q += lendis;
 251             offset += lendis;
 252         }
 253         if (q >= buffer+INSN_MAX) {
 254             unsigned char *r = buffer, *s = q;
 255             int count = p - q;
 256             while (count--)
 257                 *r++ = *s++;
 258             p -= (q - buffer);
 259             q = buffer;
 260         }
 261     } while (lenread > 0 || !(eof || feof(fp)));
 262
 263     if (fp != stdin)
 264         fclose (fp);
 265
 266     return 0;
 267 }
 268
 269 static void output_ins (unsigned long offset, unsigned char *data,
 270                         int datalen, char *insn)
 271 {
 272     int bytes;
 273     printf("%08lX  ", offset);
 274
 275     bytes = 0;
 276     while (datalen > 0 && bytes < BPL) {
 277         printf("%02X", *data++);
 278         bytes++;
 279         datalen--;
 280     }
 281
 282     printf("%*s%s\n", (BPL+1-bytes)*2, "", insn);
 283
 284     while (datalen > 0) {
 285         printf("         -");
 286         bytes = 0;
 287         while (datalen > 0 && bytes < BPL) {
 288             printf("%02X", *data++);
 289             bytes++;
 290             datalen--;
 291         }
 292         printf("\n");
 293     }
 294 }
 295
 296 /*
 297  * Skip a certain amount of data in a file, either by seeking if
 298  * possible, or if that fails then by reading and discarding.
 299  */
 300 static void skip (unsigned long dist, FILE *fp)
 301 {
 302     char buffer[256];                  /* should fit on most stacks :-) */
 303
 304     /*
 305      * Got to be careful with fseek: at least one fseek I've tried
 306      * doesn't approve of SEEK_CUR. So I'll use SEEK_SET and
 307      * ftell... horrible but apparently necessary.
 308      */
 309     if (fseek (fp, dist+ftell(fp), SEEK_SET)) {
 310         while (dist > 0) {
 311             unsigned long len = (dist < sizeof(buffer) ?
 312                                  dist : sizeof(buffer));
 313             if (fread (buffer, 1, len, fp) < len) {
 314                 perror("fread");
 315                 exit(1);
 316             }
 317             dist -= len;
 318         }
 319     }
 320 }