sys/arch/amiga/stand/binpatch/binpatch.c

   1 /*      $NetBSD: binpatch.c,v 1.10 2002/12/10 17:14:05 thorpej Exp $    */
   2
   3 /* Author: Markus Wild mw@eunet.ch ???   */
   4 /* Modified: Rob Leland leland@mitre.org */
   5
   6 #include <sys/types.h>
   7 #include <a.out.h>
   8 #include <fcntl.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <unistd.h>
  13
  14 #ifdef __NetBSD__
  15 /*
  16  * assume NMAGIC files are linked at 0 (for kernel)
  17  */
  18 #undef N_TXTADDR
  19 #define N_TXTADDR(ex) \
  20         ((N_GETMAGIC2(ex) == (ZMAGIC|0x10000) || N_GETMAGIC2(ex) == NMAGIC) ? \
  21         0 : AOUT_LDPGSZ)
  22 #endif
  23
  24
  25 static char synusage[] =
  26 "NAME\n"
  27 "\t%s - Allows the patching of BSD binaries\n"
  28 "SYNOPSIS\n"
  29 "\t%s [-HELP]\n"
  30 "\t%s [-b|-w|-l] -s symbol[[[index]][=value]] binary\n"
  31 "\t%s [-b|-w|-l] [-o offset] -s symbol [-r value] binary\n"
  32 "\t%s [-b|-w|-l] [-o offset] -a address [-r value] binary\n";
  33 static char desusage[] =
  34 "DESCRIPTION\n"
  35 "\tAllows the patching of BSD binaries, for example,a distributed\n"
  36 "\tkernel. Recient additions allows the user to index into an array\n"
  37 "\tand assign a value. Binpatch has internal variables to allow\n"
  38 "\tyou to test it on itself under NetBSD.\n"
  39 "OPTIONS\n"
  40 "\t-a  patch variable by specifying address in hex\n"
  41 "\t-b  symbol or address to be patched is 1 byte\n"
  42 "\t-l  symbol or address to be patched is 4 bytes  (default)\n"
  43 "\t-o  offset to begin patching value relative to symbol or address\n"
  44 "\t-r  replace value, and print out previous value to stdout\n"
  45 "\t-s  patch variable by specifying symbol name. Use '[]'\n"
  46 "\t    to specify the 'index'. If '-b, -w or -l' not specified\n"
  47 "\t    then index value is used like an offset. Also can use '='\n"
  48 "\t    to assign value\n"
  49 "\t-w  symbol or address to be patched is 2 bytes\n"
  50 "EXAMPLES\n"
  51 "\tThis should print 100 (this is a nice reality check...)\n"
  52 "\t\tbinpatch -l -s _hz netbsd\n"
  53 "\tNow it gets more advanced, replace the value:\n"
  54 "\t\tbinpatch -l -s _sbic_debug -r 1 netbsd\n"
  55 "\tNow patch a variable at a given 'index' not offset,\n"
  56 "\tunder NetBSD you must use '', under AmigaDos CLI '' is optional.:\n"
  57 "\t\tbinpatch -w -s '_vieww[4]' -r 0 a.out\n"
  58 "\tsame as\n"
  59 "\t\tbinpatch -w -o 8 -s _vieww -r 0 a.out\n"
  60 "\tAnother example of using []\n"
  61 "\t\tbinpatch -s '_viewl[4]' -r 0 a.out\n"
  62 "\tsame as\n"
  63 "\t\tbinpatch -o 4 -s _viewl -r 0 a.out\n"
  64 "\tOne last example using '=' and []\n"
  65 "\t\tbinpatch -w -s '_vieww[4]=2' a.out\n"
  66 "\tSo if the kernel is not finding your drives, you could enable\n"
  67 "\tall available debugging options, helping to shed light on that problem.\n"
  68 "\t\tbinpatch -l -s _sbic_debug -r 1 netbsd     scsi-level\n"
  69 "\t\tbinpatch -l -s _sddebug -r 1 netbsd        sd-level (disk-driver)\n"
  70 "\t\tbinpatch -l -s _acdebug -r 1 netbsd        autoconfig-level\n"
  71 "SEE ALSO\n"
  72 "\tbinpatch.c binpatch(1)\n";
  73
  74 extern char *optarg;
  75 extern int optind;
  76
  77 void error (char *) __attribute__((__noreturn__));
  78 static void Synopsis(char *program_name);
  79 static void Usage(char *program_name);
  80 static u_long FindAssign(char *symbol,u_long *rvalue);
  81 static void FindOffset(char *symbol,u_long *index);
  82
  83 /* The following variables are so binpatch can be tested on itself */
  84 int test = 1;
  85 int testbss;
  86 char foo = 23;
  87 char  viewb[10] = {0,0,1,0,1,1,0,1,1,1};
  88 short vieww[10] = {0,0,1,0,1,1,0,1,1,1};
  89 long  viewl[10] = {0,0,1,0,1,1,0,1,1,1};
  90 /* End of test binpatch variables */
  91 int
  92 main(int argc, char *argv[])
  93 {
  94   struct exec e;
  95   int c;
  96   u_long addr = 0, offset = 0;
  97   u_long index = 0;/* Related to offset */
  98   u_long replace = 0, do_replace = 0;
  99   char *symbol = 0;
 100   char size = 4;  /* default to long */
 101   char size_opt = 0; /* Flag to say size option was set, used with index */
 102   char *fname;
 103   char *pgname = argv[0]; /* Program name */
 104   int fd;
 105   int type, off;
 106   u_long  lval;
 107   u_short sval;
 108   u_char  cval;
 109
 110
 111   while ((c = getopt (argc, argv, "H:a:bwlr:s:o:")) != -1)
 112     switch (c)
 113       {
 114       case 'H':
 115         Usage(argv[0]);
 116         break;
 117       case 'a':
 118         if (addr || symbol)
 119           error ("only one address/symbol allowed");
 120         if (! strncmp (optarg, "0x", 2))
 121           sscanf (optarg, "%x", &addr);
 122         else
 123           addr = atoi (optarg);
 124         if (! addr)
 125           error ("invalid address");
 126         break;
 127
 128       case 'b':
 129         size = 1;
 130         size_opt = 1;
 131         break;
 132
 133       case 'w':
 134         size = 2;
 135         size_opt = 1;
 136         break;
 137
 138       case 'l':
 139         size = 4;
 140         size_opt = 1;
 141         break;
 142
 143       case 'r':
 144         do_replace = 1;
 145         if (! strncmp (optarg, "0x", 2))
 146           sscanf (optarg, "%x", &replace);
 147         else
 148           replace = atoi (optarg);
 149         break;
 150
 151       case 's':
 152         if (addr || symbol)
 153           error ("only one address/symbol allowed");
 154         symbol = optarg;
 155         break;
 156
 157       case 'o':
 158         if (offset)
 159           error ("only one offset allowed");
 160         if (! strncmp (optarg, "0x", 2))
 161           sscanf (optarg, "%x", &offset);
 162         else
 163           offset = atoi (optarg);
 164         break;
 165       }/* while switch() */
 166
 167   if (argc > 1)
 168   {
 169     if (addr || symbol)
 170     {
 171       argv += optind;
 172       argc -= optind;
 173
 174       if (argc < 1)
 175         error ("No file to patch.");
 176
 177       fname = argv[0];
 178       if ((fd = open (fname, 0)) < 0)
 179         error ("Can't open file");
 180
 181       if (read (fd, &e, sizeof (e)) != sizeof (e)
 182         || N_BADMAG (e))
 183         error ("Not a valid executable.");
 184
 185       /* fake mid, so the N_ macros work on the amiga.. */
 186       e.a_midmag |= 127 << 16;
 187
 188       if (symbol)
 189       {
 190         struct nlist nl[2];
 191         if (offset == 0)
 192         {
 193             u_long new_do_replace = 0;
 194             new_do_replace = FindAssign(symbol,&replace);
 195             if (new_do_replace && do_replace)
 196               error("Cannot use both '=' and '-r' option!");
 197             FindOffset(symbol,&index);
 198             if (size_opt)
 199                offset = index*size; /* Treat like an index */
 200             else
 201                offset = index; /* Treat index like an offset */
 202             if (new_do_replace)
 203                do_replace = new_do_replace;
 204         }
 205         nl[0].n_un.n_name = symbol;
 206         nl[1].n_un.n_name = 0;
 207         if (nlist (fname, nl) != 0)
 208         {
 209           fprintf(stderr,"Symbol is %s ",symbol);
 210           error ("Symbol not found.");
 211         }
 212         addr = nl[0].n_value;
 213         type = nl[0].n_type & N_TYPE;
 214       }
 215       else
 216       {
 217         type = N_UNDF;
 218         if (addr >= N_TXTADDR(e) && addr < N_DATADDR(e))
 219           type = N_TEXT;
 220         else if (addr >= N_DATADDR(e) && addr < N_DATADDR(e) + e.a_data)
 221           type = N_DATA;
 222       }
 223       addr += offset;
 224
 225       /* if replace-mode, have to reopen the file for writing.
 226          Can't do that from the beginning, or nlist() will not
 227          work (at least not under AmigaDOS) */
 228       if (do_replace)
 229       {
 230         close (fd);
 231         if ((fd = open (fname, 2)) == -1)
 232           error ("Can't reopen file for writing.");
 233       }
 234
 235       if (type != N_TEXT && type != N_DATA)
 236         error ("address/symbol is not in text or data section.");
 237
 238       if (type == N_TEXT)
 239         off = addr - N_TXTADDR(e) + N_TXTOFF(e);
 240       else
 241         off = addr - N_DATADDR(e) + N_DATOFF(e);
 242
 243       if (lseek (fd, off, 0) == -1)
 244         error ("lseek");
 245
 246       /* not beautiful, but works on big and little endian machines */
 247       switch (size)
 248         {
 249         case 1:
 250           if (read (fd, &cval, 1) != 1)
 251             error ("cread");
 252           lval = cval;
 253           break;
 254
 255         case 2:
 256           if (read (fd, &sval, 2) != 2)
 257             error ("sread");
 258           lval = sval;
 259           break;
 260
 261         case 4:
 262           if (read (fd, &lval, 4) != 4)
 263             error ("lread");
 264           break;
 265         }/* switch size */
 266
 267
 268       if (symbol)
 269         printf ("%s(0x%x): %d (0x%x)\n", symbol, addr, lval, lval);
 270       else
 271         printf ("0x%x: %d (0x%x)\n", addr, lval, lval);
 272
 273       if (do_replace)
 274       {
 275         if (lseek (fd, off, 0) == -1)
 276           error ("write-lseek");
 277         switch (size)
 278           {
 279           case 1:
 280             cval = replace;
 281             if (cval != replace)
 282               error ("byte-value overflow.");
 283             if (write (fd, &cval, 1) != 1)
 284               error ("cwrite");
 285             break;
 286
 287           case 2:
 288             sval = replace;
 289             if (sval != replace)
 290               error ("word-value overflow.");
 291             if (write (fd, &sval, 2) != 2)
 292               error ("swrite");
 293             break;
 294
 295           case 4:
 296             if (write (fd, &replace, 4) != 4)
 297               error ("lwrite");
 298             break;
 299           }/* switch(size) */
 300       }/* if (do_replace) */
 301
 302       close (fd);
 303     }/* if(addr || symbol ) */
 304     else
 305     {
 306       error("Must specify either address or symbol.");
 307     }
 308   }/* if argc < 1 */
 309   else
 310   {
 311     Synopsis(pgname);
 312   }
 313   return(0);
 314 }/* main () */
 315
 316
 317
 318 void error (char *str)
 319 {
 320   fprintf (stderr, "%s\n", str);
 321   exit (1);
 322 }
 323
 324 /* Give user very short help to avoid scrolling screen much */
 325 static void Synopsis(char *pgname)
 326 {
 327   fprintf(stdout,synusage,pgname,pgname,pgname,pgname,pgname);
 328 }
 329
 330
 331 static void Usage(char *pgname)
 332 {
 333   Synopsis(pgname);
 334   fprintf(stdout,desusage);
 335   exit(0);
 336 }
 337
 338
 339 /* FindOffset() - Determine if there is an offset, -or- index
 340                  embedded in the symbol.
 341                  If there is, return it, and truncate symbol to
 342                  exclude the [...].
 343                  Example: If view is declared as short view[10],
 344                           and we want to index the 3rd. element.
 345                           which is offset = (3 -1)*sizeof(short) =4.
 346                  we would use view[4], which becomes view,4.
 347                  The was the code is implemented the [value] is
 348                  treated as a index if-and-only-if a '-b -w -l' option
 349                  was given. Otherwise it is treated like an offset.
 350                  See above documentation in for of help!
 351 */
 352 static void FindOffset(char *symbol,u_long *index)
 353 {
 354   char *sb=strchr(symbol,'['); /* Start of '[', now line must
 355                                  contain matching']' */
 356   char *eb=strchr(symbol,']'); /* End of ']' */
 357   short sz=strlen(symbol);    /* symbol size */
 358   if (sb)
 359   {
 360     if (eb && (eb > sb))
 361     {
 362       if ((eb - symbol) == (sz - 1))
 363       {
 364         char *sindex; /* Start of index */
 365         u_long newindex = 0;
 366         /* In the future we could get fancy and parse the
 367            sindex string for mathmatical expressions like:
 368            (3 - 1)*2 = 4 from above example,
 369            ugh forget I mentioned ot :-) !
 370         */
 371         sindex = sb + 1;
 372         *eb = '\0';
 373         newindex = (u_long)atoi(sindex);
 374         if (*index == 0)
 375         {
 376           *index = newindex;
 377           *sb = '\0'; /* Make _view[3] look like _view */
 378         }
 379         else
 380           fprintf(stderr,"Error index can only be specified once!\n");
 381       }
 382       else
 383       {
 384         fprintf(stderr,"Error: Garbage trailing ']'\n");
 385       }
 386     }
 387     else
 388     {
 389        fprintf(stderr,"Error ']' in symbol before '[' !\n");
 390     }
 391   }/* if sb != 0 */
 392 }/* FindOffset */
 393
 394 /* FindAssign : Scans symbol name for an '=number' strips it off
 395    of the symbol and proceeds.
 396 */
 397 static u_long FindAssign(char *symbol,u_long *rvalue)
 398 {
 399   char *ce = rindex(symbol,'='); /* Assign symbol some number */
 400   char *cn = ce + 1; /* This should point at some number, no spaces allowed */
 401   u_long dr = 0; /* flag for do_replace */
 402   if (ce)
 403   {
 404     int nscan; /* number of variaables scanned in */
 405     /* get the number to assign to symbol and strip off = */
 406     for (cn=ce + 1;((*cn==' ')&&(*cn!='\0'));cn++)
 407     ;
 408     if (! strncmp (cn, "0x", 2))
 409         nscan = sscanf (cn, "%x",rvalue);
 410     else
 411         nscan = sscanf(cn,"%d",rvalue);
 412     if (nscan != 1)
 413       error("Invalid value following '='");
 414     dr = 1;
 415     *ce = '\0';/* Now were left with just symbol */
 416   }/* if (ce) */
 417   return(dr);
 418 }/* FindAssign */