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 or -v 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               case 'v':
  73                 fprintf(stderr, "NDISASM version %s compiled " __DATE__ "\n", NASM_VER);
  74                 return 0;
  75               case 'u':                /* USE32 */
  76                 bits = 32;
  77                 p++;
  78                 break;
  79               case 'b':                /* bits */
  80                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
  81                 if (!v) {
  82                     fprintf(stderr, "%s: `-b' requires an argument\n", pname);
  83                     return 1;
  84                 }
  85                 if (!strcmp(v, "16"))
  86                     bits = 16;
  87                 else if (!strcmp(v, "32"))
  88                     bits = 32;
  89                 else {
  90                     fprintf(stderr, "%s: argument to `-b' should"
  91                             " be `16' or `32'\n", pname);
  92                 }
  93                 p = "";                /* force to next argument */
  94                 break;
  95               case 'o':                /* origin */
  96                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
  97                 if (!v) {
  98                     fprintf(stderr, "%s: `-o' requires an argument\n", pname);
  99                     return 1;
 100                 }
 101                 offset = readnum (v, &rn_error);
 102                 if (rn_error) {
 103                     fprintf(stderr, "%s: `-o' requires a numeric argument\n",
 104                             pname);
 105                     return 1;
 106                 }
 107                 p = "";                /* force to next argument */
 108                 break;
 109               case 's':                /* sync point */
 110                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 111                 if (!v) {
 112                     fprintf(stderr, "%s: `-s' requires an argument\n", pname);
 113                     return 1;
 114                 }
 115                 add_sync (readnum (v, &rn_error), 0L);
 116                 if (rn_error) {
 117                     fprintf(stderr, "%s: `-s' requires a numeric argument\n",
 118                             pname);
 119                     return 1;
 120                 }
 121                 p = "";                /* force to next argument */
 122                 break;
 123               case 'e':                /* skip a header */
 124                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 125                 if (!v) {
 126                     fprintf(stderr, "%s: `-e' requires an argument\n", pname);
 127                     return 1;
 128                 }
 129                 initskip = readnum (v, &rn_error);
 130                 if (rn_error) {
 131                     fprintf(stderr, "%s: `-e' requires a numeric argument\n",
 132                             pname);
 133                     return 1;
 134                 }
 135                 p = "";                /* force to next argument */
 136                 break;
 137               case 'k':                /* skip a region */
 138                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 139                 if (!v) {
 140                     fprintf(stderr, "%s: `-k' requires an argument\n", pname);
 141                     return 1;
 142                 }
 143                 vv = strchr(v, ',');
 144                 if (!vv) {
 145                     fprintf(stderr, "%s: `-k' requires two numbers separated"
 146                             " by a comma\n", pname);
 147                     return 1;
 148                 }
 149                 *vv++ = '\0';
 150                 nextsync = readnum (v, &rn_error);
 151                 if (rn_error) {
 152                     fprintf(stderr, "%s: `-k' requires numeric arguments\n",
 153                             pname);
 154                     return 1;
 155                 }
 156                 synclen = readnum (vv, &rn_error);
 157                 if (rn_error) {
 158                     fprintf(stderr, "%s: `-k' requires numeric arguments\n",
 159                             pname);
 160                     return 1;
 161                 }
 162                 add_sync (nextsync, synclen);
 163                 p = "";                /* force to next argument */
 164                 break;
 165             case 'p':                  /* preferred vendor */
 166                 v = p[1] ? p+1 : --argc ? *++argv : NULL;
 167                 if (!v) {
 168                     fprintf(stderr, "%s: `-p' requires an argument\n", pname);
 169                     return 1;
 170                 }
 171                 if ( !strcmp(v, "intel") ) {
 172                   prefer = 0;   /* Default */
 173                 } else if ( !strcmp(v, "amd") ) {
 174                   prefer = IF_AMD|IF_3DNOW;
 175                 } else if ( !strcmp(v, "cyrix") ) {
 176                   prefer = IF_CYRIX|IF_3DNOW;
 177                 } else if ( !strcmp(v, "idt") || !strcmp(v, "centaur") ||
 178                             !strcmp(v, "winchip") ) {
 179                   prefer = IF_3DNOW;
 180                 } else {
 181                   fprintf(stderr, "%s: unknown vendor `%s' specified with `-p'\n", pname, v);
 182                   return 1;
 183                 }
 184                 p = "";                /* force to next argument */
 185                 break;
 186             default:                                                    /*bf*/
 187                 fprintf(stderr, "%s: unrecognised option `-%c'\n",
 188                         pname, *p);
 189                 return 1;
 190             }
 191         } else if (!filename) {
 192             filename = p;
 193         } else {
 194             fprintf(stderr, "%s: more than one filename specified\n", pname);
 195             return 1;
 196         }
 197     }
 198
 199     if (!filename) {
 200         fprintf(stderr, help, pname);
 201         return 0;
 202     }
 203
 204     if (strcmp(filename, "-")) {
 205         fp = fopen(filename, "rb");
 206         if (!fp) {
 207             fprintf(stderr, "%s: unable to open `%s': %s\n",
 208                     pname, filename, strerror(errno));
 209             return 1;
 210         }
 211     } else
 212         fp = stdin;
 213
 214     if (initskip > 0)
 215         skip (initskip, fp);
 216
 217     /*
 218      * This main loop is really horrible, and wants rewriting with
 219      * an axe. It'll stay the way it is for a while though, until I
 220      * find the energy...
 221      */
 222
 223     p = q = buffer;
 224     nextsync = next_sync (offset, &synclen);
 225     do {
 226         unsigned long to_read = buffer+sizeof(buffer)-p;
 227         if (to_read > nextsync-offset-(p-q))
 228             to_read = nextsync-offset-(p-q);
 229         if (to_read) {
 230             lenread = fread (p, 1, to_read, fp);
 231             if (lenread == 0)
 232                 eof = TRUE;            /* help along systems with bad feof */
 233         } else
 234             lenread = 0;
 235         p += lenread;
 236         if ((unsigned long)offset == nextsync) {
 237             if (synclen) {
 238                 printf("%08lX  skipping 0x%lX bytes\n", offset, synclen);
 239                 offset += synclen;
 240                 skip (synclen, fp);
 241             }
 242             p = q = buffer;
 243             nextsync = next_sync (offset, &synclen);
 244         }
 245         while (p > q && (p - q >= INSN_MAX || lenread == 0)) {
 246             lendis = disasm (q, outbuf, bits, offset, autosync, prefer);
 247             if (!lendis || lendis > (p - q) ||
 248                 (unsigned long)lendis > nextsync-offset)
 249                 lendis = eatbyte (q, outbuf);
 250             output_ins (offset, q, lendis, outbuf);
 251             q += lendis;
 252             offset += lendis;
 253         }
 254         if (q >= buffer+INSN_MAX) {
 255             unsigned char *r = buffer, *s = q;
 256             int count = p - q;
 257             while (count--)
 258                 *r++ = *s++;
 259             p -= (q - buffer);
 260             q = buffer;
 261         }
 262     } while (lenread > 0 || !(eof || feof(fp)));
 263
 264     if (fp != stdin)
 265         fclose (fp);
 266
 267     return 0;
 268 }
 269
 270 static void output_ins (unsigned long offset, unsigned char *data,
 271                         int datalen, char *insn)
 272 {
 273     int bytes;
 274     printf("%08lX  ", offset);
 275
 276     bytes = 0;
 277     while (datalen > 0 && bytes < BPL) {
 278         printf("%02X", *data++);
 279         bytes++;
 280         datalen--;
 281     }
 282
 283     printf("%*s%s\n", (BPL+1-bytes)*2, "", insn);
 284
 285     while (datalen > 0) {
 286         printf("         -");
 287         bytes = 0;
 288         while (datalen > 0 && bytes < BPL) {
 289             printf("%02X", *data++);
 290             bytes++;
 291             datalen--;
 292         }
 293         printf("\n");
 294     }
 295 }
 296
 297 /*
 298  * Skip a certain amount of data in a file, either by seeking if
 299  * possible, or if that fails then by reading and discarding.
 300  */
 301 static void skip (unsigned long dist, FILE *fp)
 302 {
 303     char buffer[256];                  /* should fit on most stacks :-) */
 304
 305     /*
 306      * Got to be careful with fseek: at least one fseek I've tried
 307      * doesn't approve of SEEK_CUR. So I'll use SEEK_SET and
 308      * ftell... horrible but apparently necessary.
 309      */
 310     if (fseek (fp, dist+ftell(fp), SEEK_SET)) {
 311         while (dist > 0) {
 312             unsigned long len = (dist < sizeof(buffer) ?
 313                                  dist : sizeof(buffer));
 314             if (fread (buffer, 1, len, fp) < len) {
 315                 perror("fread");
 316                 exit(1);
 317             }
 318             dist -= len;
 319         }
 320     }
 321 }