tools/cmpmrg_text.c

   1 /*
   2  * ia32rtools
   3  * (C) notaz, 2013,2014
   4  *
   5  * This work is licensed under the terms of 3-clause BSD license.
   6  * See COPYING file in the top-level directory.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <linux/coff.h>
  13 #include <assert.h>
  14 #include <stdint.h>
  15
  16 #include "my_assert.h"
  17
  18 /* http://www.delorie.com/djgpp/doc/coff/ */
  19
  20 typedef struct {
  21   unsigned short f_magic;         /* magic number             */
  22   unsigned short f_nscns;         /* number of sections       */
  23   unsigned int   f_timdat;        /* time & date stamp        */
  24   unsigned int   f_symptr;        /* file pointer to symtab   */
  25   unsigned int   f_nsyms;         /* number of symtab entries */
  26   unsigned short f_opthdr;        /* sizeof(optional hdr)     */
  27   unsigned short f_flags;         /* flags                    */
  28 } FILHDR;
  29
  30 typedef struct {
  31   unsigned short magic;          /* type of file                         */
  32   unsigned short vstamp;         /* version stamp                        */
  33   unsigned int   tsize;          /* text size in bytes, padded to FW bdry*/
  34   unsigned int   dsize;          /* initialized data    "  "             */
  35   unsigned int   bsize;          /* uninitialized data  "  "             */
  36   unsigned int   entry;          /* entry pt.                            */
  37   unsigned int   text_start;     /* base of text used for this file      */
  38   unsigned int   data_start;     /* base of data used for this file      */
  39 } AOUTHDR;
  40
  41 typedef struct {
  42   char           s_name[8];  /* section name                     */
  43   unsigned int   s_paddr;    /* physical address, aliased s_nlib */
  44   unsigned int   s_vaddr;    /* virtual address                  */
  45   unsigned int   s_size;     /* section size                     */
  46   unsigned int   s_scnptr;   /* file ptr to raw data for section */
  47   unsigned int   s_relptr;   /* file ptr to relocation           */
  48   unsigned int   s_lnnoptr;  /* file ptr to line numbers         */
  49   unsigned short s_nreloc;   /* number of relocation entries     */
  50   unsigned short s_nlnno;    /* number of line number entries    */
  51   unsigned int   s_flags;    /* flags                            */
  52 } SCNHDR;
  53
  54 typedef struct {
  55   unsigned int  r_vaddr;   /* address of relocation      */
  56   unsigned int  r_symndx;  /* symbol we're adjusting for */
  57   unsigned short r_type;    /* type of relocation         */
  58 } __attribute__((packed)) RELOC;
  59
  60 typedef struct {
  61   union {
  62     char e_name[E_SYMNMLEN];
  63     struct {
  64       unsigned int e_zeroes;
  65       unsigned int e_offset;
  66     } e;
  67   } e;
  68   unsigned int e_value;
  69   short e_scnum;
  70   unsigned short e_type;
  71   unsigned char e_sclass;
  72   unsigned char e_numaux;
  73 } __attribute__((packed)) SYMENT;
  74
  75 #define C_EXT 2
  76
  77 struct my_symtab {
  78   unsigned int addr;
  79   //unsigned int fpos; // for patching
  80   unsigned int is_text:1;
  81   char *name;
  82 };
  83
  84 struct my_sect_info {
  85         long scnhdr_fofs;
  86         long sect_fofs;
  87         long reloc_fofs;
  88         uint8_t *data;
  89         long size;
  90         RELOC *relocs;
  91         long reloc_cnt;
  92 };
  93
  94 static int symt_cmp(const void *p1_, const void *p2_)
  95 {
  96         const struct my_symtab *p1 = p1_, *p2 = p2_;
  97         return p1->addr - p2->addr;
  98 }
  99
 100 void parse_headers(FILE *f, unsigned int *base_out,
 101         struct my_sect_info *sect_i,
 102         struct my_symtab **symtab_out, long *sym_cnt,
 103         struct my_symtab **raw_symtab_out, long *raw_sym_cnt)
 104 {
 105         struct my_symtab *symt_txt = NULL;
 106         struct my_symtab *symt_all = NULL;
 107         char *stringtab = NULL;
 108         unsigned int base = 0;
 109         int text_scnum = 0;
 110         long filesize;
 111         char symname[9];
 112         long opthdr_pos;
 113         long reloc_size;
 114         FILHDR hdr;
 115         AOUTHDR opthdr;
 116         SCNHDR scnhdr;
 117         SYMENT syment;
 118         int i, s, val;
 119         int ret;
 120
 121         ret = fseek(f, 0, SEEK_END);
 122         my_assert(ret, 0);
 123
 124         filesize = ftell(f);
 125
 126         ret = fseek(f, 0, SEEK_SET);
 127         my_assert(ret, 0);
 128
 129         ret = fread(&hdr, 1, sizeof(hdr), f);
 130         my_assert(ret, sizeof(hdr));
 131
 132         if (hdr.f_magic == 0x5a4d) // MZ
 133         {
 134                 ret = fseek(f, 0x3c, SEEK_SET);
 135                 my_assert(ret, 0);
 136                 ret = fread(&val, 1, sizeof(val), f);
 137                 my_assert(ret, sizeof(val));
 138
 139                 ret = fseek(f, val, SEEK_SET);
 140                 my_assert(ret, 0);
 141                 ret = fread(&val, 1, sizeof(val), f);
 142                 my_assert(ret, sizeof(val));
 143                 my_assert(val, 0x4550); // PE
 144
 145                 // should be COFF now
 146                 ret = fread(&hdr, 1, sizeof(hdr), f);
 147                 my_assert(ret, sizeof(hdr));
 148         }
 149
 150         my_assert(hdr.f_magic, COFF_I386MAGIC);
 151
 152         if (hdr.f_opthdr != 0)
 153         {
 154                 opthdr_pos = ftell(f);
 155
 156                 if (hdr.f_opthdr < sizeof(opthdr))
 157                         my_assert(1, 0);
 158
 159                 ret = fread(&opthdr, 1, sizeof(opthdr), f);
 160                 my_assert(ret, sizeof(opthdr));
 161                 my_assert(opthdr.magic, COFF_ZMAGIC);
 162
 163                 //printf("text_start: %x\n", opthdr.text_start);
 164
 165                 if (hdr.f_opthdr > sizeof(opthdr)) {
 166                         ret = fread(&base, 1, sizeof(base), f);
 167                         my_assert(ret, sizeof(base));
 168                         //printf("base: %x\n", base);
 169                 }
 170                 ret = fseek(f, opthdr_pos + hdr.f_opthdr, SEEK_SET);
 171                 my_assert(ret, 0);
 172         }
 173
 174         // note: assuming first non-empty one is .text ..
 175         for (s = 0; s < hdr.f_nscns; s++) {
 176                 sect_i->scnhdr_fofs = ftell(f);
 177
 178                 ret = fread(&scnhdr, 1, sizeof(scnhdr), f);
 179                 my_assert(ret, sizeof(scnhdr));
 180
 181                 if (scnhdr.s_size != 0) {
 182                         text_scnum = s + 1;
 183                         break;
 184                 }
 185         }
 186         my_assert(s < hdr.f_nscns, 1);
 187
 188 #if 0
 189         printf("f_nsyms:  %x\n", hdr.f_nsyms);
 190         printf("s_name:   '%s'\n", scnhdr.s_name);
 191         printf("s_vaddr:  %x\n", scnhdr.s_vaddr);
 192         printf("s_size:   %x\n", scnhdr.s_size);
 193         //printf("s_scnptr: %x\n", scnhdr.s_scnptr);
 194         printf("s_nreloc: %x\n", scnhdr.s_nreloc);
 195         printf("--\n");
 196 #endif
 197
 198         ret = fseek(f, scnhdr.s_scnptr, SEEK_SET);
 199         my_assert(ret, 0);
 200
 201         sect_i->data = malloc(scnhdr.s_size);
 202         my_assert_not(sect_i->data, NULL);
 203         ret = fread(sect_i->data, 1, scnhdr.s_size, f);
 204         my_assert(ret, scnhdr.s_size);
 205
 206         sect_i->sect_fofs = scnhdr.s_scnptr;
 207         sect_i->size = scnhdr.s_size;
 208
 209         // relocs
 210         ret = fseek(f, scnhdr.s_relptr, SEEK_SET);
 211         my_assert(ret, 0);
 212
 213         reloc_size = scnhdr.s_nreloc * sizeof(sect_i->relocs[0]);
 214         sect_i->relocs = malloc(reloc_size + 1);
 215         my_assert_not(sect_i->relocs, NULL);
 216         ret = fread(sect_i->relocs, 1, reloc_size, f);
 217         my_assert(ret, reloc_size);
 218
 219         sect_i->reloc_cnt = scnhdr.s_nreloc;
 220         sect_i->reloc_fofs = scnhdr.s_relptr;
 221
 222         if (base != 0 && base_out != NULL)
 223                 *base_out = base + scnhdr.s_vaddr;
 224
 225         if (symtab_out == NULL || sym_cnt == NULL)
 226                 return;
 227
 228         // symtab
 229         if (hdr.f_nsyms != 0) {
 230                 symname[8] = 0;
 231
 232                 symt_txt = malloc(hdr.f_nsyms * sizeof(symt_txt[0]) + 1);
 233                 my_assert_not(symt_txt, NULL);
 234                 symt_all = malloc(hdr.f_nsyms * sizeof(symt_all[0]) + 1);
 235                 my_assert_not(symt_all, NULL);
 236
 237                 ret = fseek(f, hdr.f_symptr
 238                                 + hdr.f_nsyms * sizeof(syment), SEEK_SET);
 239                 my_assert(ret, 0);
 240                 ret = fread(&i, 1, sizeof(i), f);
 241                 my_assert(ret, sizeof(i));
 242                 my_assert((unsigned int)i < filesize, 1);
 243
 244                 stringtab = malloc(i);
 245                 my_assert_not(stringtab, NULL);
 246                 memset(stringtab, 0, 4);
 247                 ret = fread(stringtab + 4, 1, i - 4, f);
 248                 my_assert(ret, i - 4);
 249
 250                 ret = fseek(f, hdr.f_symptr, SEEK_SET);
 251                 my_assert(ret, 0);
 252         }
 253
 254         for (i = s = 0; i < hdr.f_nsyms; i++) {
 255                 //long pos = ftell(f);
 256
 257                 ret = fread(&syment, 1, sizeof(syment), f);
 258                 my_assert(ret, sizeof(syment));
 259
 260                 strncpy(symname, syment.e.e_name, 8);
 261                 //printf("%3d %2d %08x '%s'\n", syment.e_sclass,
 262                 //      syment.e_scnum, syment.e_value, symname);
 263
 264                 symt_all[i].addr = syment.e_value;
 265                 //symt_all[i].fpos = pos;
 266                 if (syment.e.e.e_zeroes == 0)
 267                         symt_all[i].name = stringtab + syment.e.e.e_offset;
 268                 else
 269                         symt_all[i].name = strdup(symname);
 270
 271                 symt_all[i].is_text = (syment.e_scnum == text_scnum);
 272                 if (symt_all[i].is_text && syment.e_sclass == C_EXT) {
 273                         symt_txt[s] = symt_all[i];
 274                         s++;
 275                 }
 276
 277                 if (syment.e_numaux) {
 278                         ret = fseek(f, syment.e_numaux * sizeof(syment),
 279                                     SEEK_CUR);
 280                         my_assert(ret, 0);
 281                         i += syment.e_numaux;
 282                 }
 283         }
 284
 285         if (symt_txt != NULL)
 286                 qsort(symt_txt, s, sizeof(symt_txt[0]), symt_cmp);
 287
 288         *sym_cnt = s;
 289         *symtab_out = symt_txt;
 290         *raw_sym_cnt = i;
 291         *raw_symtab_out = symt_all;
 292 }
 293
 294 static int handle_pad(uint8_t *d_obj, uint8_t *d_exe, int maxlen)
 295 {
 296         static const uint8_t p7[7] = { 0x8d, 0xa4, 0x24, 0x00, 0x00, 0x00, 0x00 };
 297         static const uint8_t p6[6] = { 0x8d, 0x9b, 0x00, 0x00, 0x00, 0x00 };
 298         static const uint8_t p5[5] = { 0x05, 0x00, 0x00, 0x00, 0x00 }; // add eax, 0
 299         static const uint8_t p4[4] = { 0x8d, 0x64, 0x24, 0x00 }; // lea
 300         static const uint8_t p3[3] = { 0x8d, 0x49, 0x00 }; // lea ecx, [ecx]
 301         static const uint8_t p2[2] = { 0x8b, 0xff }; // mov edi, edi
 302         static const uint8_t p1[1] = { 0x90 }; // nop
 303         int len;
 304         int i;
 305
 306         for (i = 0; i < maxlen; i++)
 307                 if (d_exe[i] != 0xcc)
 308                         break;
 309
 310         for (len = i; len > 0; )
 311         {
 312                 i = len;
 313                 if (i > 7)
 314                         i = 7;
 315
 316                 switch (i) {
 317                 #define CASE(x) \
 318                 case sizeof(p ## x): \
 319                         if (memcmp(d_obj, p ## x, sizeof(p ## x))) \
 320                                 return 0; \
 321                         memset(d_obj, 0xcc, sizeof(p ## x)); \
 322                         break;
 323                 CASE(7)
 324                 CASE(6)
 325                 CASE(5)
 326                 CASE(4)
 327                 CASE(3)
 328                 CASE(2)
 329                 CASE(1)
 330                 default:
 331                         printf("%s: unhandled len: %d\n", __func__, len);
 332                         return 0;
 333                 #undef CASE
 334                 }
 335
 336                 len -= i;
 337                 d_obj += i;
 338         }
 339
 340         return 1;
 341 }
 342
 343 struct equiv_opcode {
 344         signed char len;
 345         signed char ofs;
 346         unsigned short cmp_rm:1;
 347         unsigned short simple:1;
 348         uint8_t v_masm[8];
 349         uint8_t v_masm_mask[8];
 350         uint8_t v_msvc[8];
 351         uint8_t v_msvc_mask[8];
 352 } equiv_ops[] = {
 353         // cmp    $0x11,%ax
 354         { 4, -1, 0, 0,
 355          { 0x66,0x83,0xf8,0x03 }, { 0xff,0xff,0xff,0x00 },
 356          { 0x66,0x3d,0x03,0x00 }, { 0xff,0xff,0x00,0xff }, },
 357         // lea    -0x1(%ebx,%eax,1),%esi // op mod/rm sib offs
 358         // mov, test, imm grp 1
 359         { 3, -2, 1, 0,
 360          { 0x8d,0x74,0x03 }, { 0xf0,0x07,0xc0 },
 361          { 0x8d,0x74,0x18 }, { 0xf0,0x07,0xc0 }, },
 362         // movzbl 0x58f24a(%eax,%ecx,1),%eax
 363         { 4, -3, 1, 0,
 364          { 0x0f,0xb6,0x84,0x08 }, { 0xff,0xff,0x07,0xc0 },
 365          { 0x0f,0xb6,0x84,0x01 }, { 0xff,0xff,0x07,0xc0 }, },
 366         // inc/dec
 367         { 3, -2, 1, 0,
 368          { 0xfe,0x4c,0x03 }, { 0xfe,0xff,0xc0 },
 369          { 0xfe,0x4c,0x18 }, { 0xfe,0xff,0xc0 }, },
 370         // cmp
 371         { 3, -2, 1, 0,
 372          { 0x38,0x0c,0x0c }, { 0xff,0xff,0xc0 },
 373          { 0x38,0x0c,0x30 }, { 0xff,0xff,0xc0 }, },
 374         // test   %dl,%bl
 375         { 2, -1, 1, 0,
 376          { 0x84,0xd3 }, { 0xfe,0xc0 },
 377          { 0x84,0xda }, { 0xfe,0xc0 }, },
 378         // cmp    r,r/m vs rm/r
 379         { 2, 0, 1, 0,
 380          { 0x3a,0xca }, { 0xff,0xc0 },
 381          { 0x38,0xd1 }, { 0xff,0xc0 }, },
 382         // rep + 66 prefix
 383         { 2, 0, 0, 0,
 384          { 0xf3,0x66 }, { 0xfe,0xff },
 385          { 0x66,0xf3 }, { 0xff,0xfe }, },
 386         // fadd   st, st(0) vs st(0), st
 387         { 2, 0, 0, 0,
 388          { 0xd8,0xc0 }, { 0xff,0xf7 },
 389          { 0xdc,0xc0 }, { 0xff,0xf7 }, },
 390         // [esp] vs [esp+0]
 391         { 4, -1, 0, 0,
 392          { 0x00,0x04,0x24,0x90 }, { 0x00,0xc7,0xff,0xff },
 393          { 0x00,0x44,0x24,0x00 }, { 0x00,0xc7,0xff,0xff }, },
 394         { 5, -1, 0, 0,
 395          { 0x00,0x04,0x24,0x00,0x90 }, { 0x00,0xc7,0xff,0x00,0xff },
 396          { 0x00,0x44,0x24,0x00,0x00 }, { 0x00,0xc7,0xff,0xff,0x00 }, },
 397
 398         // various align insns/fillups
 399         { 2, -1, 0, 0,
 400          { 0x8b,0xff }, { 0xff,0xff },
 401          { 0x8b,0xc0 }, { 0xff,0xff }, },
 402         { 2, 0, 0, 1,
 403          { 0x00,0x00 }, { 0x00,0x00 },
 404          { 0x8b,0xc0 }, { 0xff,0xff }, },
 405         { 3, 0, 0, 1,
 406          { 0x00,0x00,0x00 }, { 0x50,0x00,0x00 },
 407          { 0x2e,0x8b,0xc0 }, { 0xff,0xff,0xff }, },
 408
 409         // broad filters (may take too much..)
 410         // testb  $0x4,0x1d(%esi,%eax,1)
 411         // movb, push, ..
 412         { 3, -2, 1, 0,
 413          { 0xf6,0x44,0x06 }, { 0x00,0x07,0xc0 },
 414          { 0xf6,0x44,0x30 }, { 0x00,0x07,0xc0 }, },
 415 };
 416
 417 static int cmp_mask(uint8_t *d, uint8_t *expect, uint8_t *mask, int len)
 418 {
 419         int i;
 420
 421         for (i = 0; i < len; i++)
 422                 if ((d[i] & mask[i]) != (expect[i] & mask[i]))
 423                         return 1;
 424
 425         return 0;
 426 }
 427
 428 static int check_equiv(uint8_t *d_obj, uint8_t *d_exe, int maxlen)
 429 {
 430         uint8_t vo, ve, vo2, ve2;
 431         int i, jo, je;
 432         int len, ofs;
 433
 434         for (i = 0; i < sizeof(equiv_ops) / sizeof(equiv_ops[0]); i++)
 435         {
 436                 struct equiv_opcode *op = &equiv_ops[i];
 437
 438                 len = op->len;
 439                 if (maxlen < len)
 440                         continue;
 441
 442                 ofs = op->ofs;
 443                 if (cmp_mask(d_obj + ofs, op->v_masm,
 444                              op->v_masm_mask, len))
 445                         continue;
 446                 if (cmp_mask(d_exe + ofs, op->v_msvc,
 447                              op->v_msvc_mask, len))
 448                         continue;
 449
 450                 if (op->simple)
 451                         return len + ofs;
 452
 453                 jo = je = 0;
 454                 d_obj += ofs;
 455                 d_exe += ofs;
 456                 while (1)
 457                 {
 458                         for (; jo < len; jo++)
 459                                 if (op->v_masm_mask[jo] != 0xff)
 460                                         break;
 461                         for (; je < len; je++)
 462                                 if (op->v_msvc_mask[je] != 0xff)
 463                                         break;
 464
 465                         if ((jo == len && je != len) || (jo != len && je == len)) {
 466                                 printf("invalid equiv_op #%ld\n", op - equiv_ops);
 467                                 return -1;
 468                         }
 469                         if (jo == len)
 470                                 return len + ofs; // matched
 471
 472                         // var byte
 473                         vo = d_obj[jo] & ~op->v_masm_mask[jo];
 474                         ve = d_exe[je] & ~op->v_msvc_mask[je];
 475                         if (op->cmp_rm && op->v_masm_mask[jo] == 0xc0) {
 476                                 vo2 = vo >> 3;
 477                                 vo &= 7;
 478                                 ve2 = ve & 7;
 479                                 ve >>= 3;
 480                                 if (vo != ve || vo2 != ve2)
 481                                         return -1;
 482                         }
 483                         else {
 484                                 if (vo != ve)
 485                                         return -1;
 486                         }
 487
 488                         jo++;
 489                         je++;
 490                 }
 491         }
 492
 493         return -1;
 494 }
 495
 496 static void fill_int3(unsigned char *d, int len)
 497 {
 498         while (len-- > 0) {
 499                 if (d[0] == 0xcc && d[1] == 0xcc)
 500                         break;
 501                 *d++ = 0xcc;
 502         }
 503 }
 504
 505 int main(int argc, char *argv[])
 506 {
 507         unsigned int base = 0, addr, end, sym, *t;
 508         struct my_sect_info s_text_obj, s_text_exe;
 509         struct my_symtab *raw_syms_obj = NULL;
 510         struct my_symtab *syms_obj = NULL;
 511         long sym_cnt_obj, raw_sym_cnt_obj;
 512         FILE *f_obj, *f_exe;
 513         SCNHDR tmphdr;
 514         long sztext_cmn;
 515         int do_cmp = 1;
 516         int retval = 1;
 517         int left;
 518         int arg;
 519         int ret;
 520         int i;
 521
 522         for (arg = 1; arg < argc; arg++) {
 523                 if (!strcmp(argv[arg], "-n"))
 524                         do_cmp = 0;
 525                 else
 526                         break;
 527         }
 528
 529         if (argc != arg + 2) {
 530                 printf("usage:\n%s [-n] <a_obj> <exe>\n", argv[0]);
 531                 return 1;
 532         }
 533
 534         f_obj = fopen(argv[arg++], "r+b");
 535         if (f_obj == NULL) {
 536                 fprintf(stderr, "%s: ", argv[1]);
 537                 perror("");
 538                 return 1;
 539         }
 540
 541         f_exe = fopen(argv[arg++], "r");
 542         if (f_exe == NULL) {
 543                 fprintf(stderr, "%s: ", argv[2]);
 544                 perror("");
 545                 return 1;
 546         }
 547
 548         parse_headers(f_obj, NULL, &s_text_obj, &syms_obj, &sym_cnt_obj,
 549                       &raw_syms_obj, &raw_sym_cnt_obj);
 550         parse_headers(f_exe, &base, &s_text_exe, NULL, NULL, NULL, NULL);
 551
 552         sztext_cmn = s_text_obj.size;
 553         if (sztext_cmn > s_text_exe.size)
 554                 sztext_cmn = s_text_exe.size;
 555
 556         if (sztext_cmn == 0) {
 557                 printf("bad .text size(s): %ld, %ld\n",
 558                         s_text_obj.size, s_text_exe.size);
 559                 return 1;
 560         }
 561
 562         for (i = 0; i < s_text_obj.reloc_cnt; i++)
 563         {
 564                 unsigned int a = s_text_obj.relocs[i].r_vaddr;
 565                 //printf("%04x %08x\n", s_text_obj.relocs[i].r_type, a);
 566
 567                 switch (s_text_obj.relocs[i].r_type) {
 568                 case 0x06: // RELOC_ADDR32
 569                 case 0x14: // RELOC_REL32
 570                         // must preserve stored val,
 571                         // so trash exe so that cmp passes
 572                         memcpy(s_text_exe.data + a, s_text_obj.data + a, 4);
 573                         break;
 574                 default:
 575                         printf("unknown reloc %x @%08x/%08x\n",
 576                                 s_text_obj.relocs[i].r_type, a, base + a);
 577                         return 1;
 578                 }
 579         }
 580
 581         if (do_cmp)
 582         for (i = 0; i < sztext_cmn; i++)
 583         {
 584                 if (s_text_obj.data[i] == s_text_exe.data[i])
 585                         continue;
 586
 587                 left = sztext_cmn - i;
 588
 589                 if (s_text_exe.data[i] == 0xcc || s_text_exe.data[i] == 0x90) {
 590                         // padding
 591                         if (handle_pad(s_text_obj.data + i,
 592                             s_text_exe.data + i, left))
 593                                 continue;
 594                 }
 595
 596                 ret = check_equiv(s_text_obj.data + i, s_text_exe.data + i, left);
 597                 if (ret >= 0) {
 598                         i += ret - 1;
 599                         continue;
 600                 }
 601
 602                 printf("%x: %02x vs %02x\n", base + i,
 603                         s_text_obj.data[i], s_text_exe.data[i]);
 604                 goto out;
 605         }
 606
 607         // fill removed funcs with 'int3'
 608         for (i = 0; i < sym_cnt_obj; i++) {
 609                 if (strncmp(syms_obj[i].name, "rm_", 3))
 610                         continue;
 611
 612                 addr = syms_obj[i].addr;
 613                 end = (i < sym_cnt_obj - 1)
 614                         ? syms_obj[i + 1].addr : s_text_obj.size;
 615                 if (addr >= s_text_obj.size || end > s_text_obj.size) {
 616                         printf("addr OOR: %x-%x '%s'\n", addr, end,
 617                                 syms_obj[i].name);
 618                         goto out;
 619                 }
 620                 fill_int3(s_text_obj.data + addr, end - addr);
 621         }
 622
 623         // remove relocs
 624         for (i = 0; i < s_text_obj.reloc_cnt; i++) {
 625                 addr = s_text_obj.relocs[i].r_vaddr;
 626                 sym = s_text_obj.relocs[i].r_symndx;
 627                 if (addr > s_text_obj.size - 4) {
 628                         printf("reloc addr OOR: %x\n", addr);
 629                         goto out;
 630                 }
 631                 if (sym >= raw_sym_cnt_obj) {
 632                         printf("reloc sym OOR: %d/%ld\n",
 633                                 sym, raw_sym_cnt_obj);
 634                         goto out;
 635                 }
 636 #if 0
 637                 printf("r %08x -> %08x %s\n", base + addr,
 638                         raw_syms_obj[sym].addr,
 639                         raw_syms_obj[sym].name);
 640 #endif
 641                 t = (unsigned int *)(s_text_obj.data + addr);
 642                 if (t[0] == 0xcccccccc
 643                  || t[-1] == 0xcccccccc) { // jumptab of a func?
 644                         t[0] = 0xcccccccc;
 645                         memmove(&s_text_obj.relocs[i],
 646                                 &s_text_obj.relocs[i + 1],
 647                                 (s_text_obj.reloc_cnt - i - 1)
 648                                  * sizeof(s_text_obj.relocs[0]));
 649                         i--;
 650                         s_text_obj.reloc_cnt--;
 651                 }
 652 #if 0
 653                 // note: branches/calls already linked,
 654                 // so only useful for dd refs
 655                 // XXX: rm'd because of switch tables
 656                 else if (raw_syms_obj[sym].is_text) {
 657                         unsigned int addr2 = raw_syms_obj[sym].addr;
 658                         if (s_text_obj.data[addr2] == 0xcc) {
 659                                 printf("warning: reloc %08x -> %08x "
 660                                         "points to rm'd target '%s'\n",
 661                                         base + addr, base + addr2,
 662                                         raw_syms_obj[sym].name);
 663                         }
 664                 }
 665 #endif
 666         }
 667
 668         // patch .text
 669         ret = fseek(f_obj, s_text_obj.sect_fofs, SEEK_SET);
 670         my_assert(ret, 0);
 671         ret = fwrite(s_text_obj.data, 1, s_text_obj.size, f_obj);
 672         my_assert(ret, s_text_obj.size);
 673
 674         // patch relocs
 675         ret = fseek(f_obj, s_text_obj.reloc_fofs, SEEK_SET);
 676         my_assert(ret, 0);
 677         ret = fwrite(s_text_obj.relocs, sizeof(s_text_obj.relocs[0]),
 678                 s_text_obj.reloc_cnt, f_obj);
 679         my_assert(ret, s_text_obj.reloc_cnt);
 680
 681         ret = fseek(f_obj, s_text_obj.scnhdr_fofs, SEEK_SET);
 682         my_assert(ret, 0);
 683         ret = fread(&tmphdr, 1, sizeof(tmphdr), f_obj);
 684         my_assert(ret, sizeof(tmphdr));
 685
 686         tmphdr.s_nreloc = s_text_obj.reloc_cnt;
 687
 688         ret = fseek(f_obj, s_text_obj.scnhdr_fofs, SEEK_SET);
 689         my_assert(ret, 0);
 690         ret = fwrite(&tmphdr, 1, sizeof(tmphdr), f_obj);
 691         my_assert(ret, sizeof(tmphdr));
 692
 693         fclose(f_obj);
 694         fclose(f_exe);
 695
 696         retval = 0;
 697 out:
 698         return retval;
 699 }