1 /* rddbg.c -- Read debugging information into a generic form. 2 Copyright (C) 1995-2016 Free Software Foundation, Inc. 3 Written by Ian Lance Taylor <ian@cygnus.com>. 4 5 This file is part of GNU Binutils. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 20 02110-1301, USA. */ 21 22 23 /* This file reads debugging information into a generic form. This 24 file knows how to dig the debugging information out of an object 25 file. */ 26 27 #include "sysdep.h" 28 #include "bfd.h" 29 #include "libiberty.h" 30 #include "bucomm.h" 31 #include "debug.h" 32 #include "budbg.h" 33 34 static bfd_boolean read_section_stabs_debugging_info 35 (bfd *, asymbol **, long, void *, bfd_boolean *); 36 static bfd_boolean read_symbol_stabs_debugging_info 37 (bfd *, asymbol **, long, void *, bfd_boolean *); 38 static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *); 39 static void save_stab (int, int, bfd_vma, const char *); 40 static void stab_context (void); 41 static void free_saved_stabs (void); 42 43 /* Read debugging information from a BFD. Returns a generic debugging 44 pointer. */ 45 46 void * 47 read_debugging_info (bfd *abfd, asymbol **syms, long symcount, bfd_boolean no_messages) 48 { 49 void *dhandle; 50 bfd_boolean found; 51 52 dhandle = debug_init (); 53 if (dhandle == NULL) 54 return NULL; 55 56 if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle, 57 &found)) 58 return NULL; 59 60 if (bfd_get_flavour (abfd) == bfd_target_aout_flavour) 61 { 62 if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle, 63 &found)) 64 return NULL; 65 } 66 67 if (bfd_get_flavour (abfd) == bfd_target_ieee_flavour) 68 { 69 if (! read_ieee_debugging_info (abfd, dhandle, &found)) 70 return NULL; 71 } 72 73 /* Try reading the COFF symbols if we didn't find any stabs in COFF 74 sections. */ 75 if (! found 76 && bfd_get_flavour (abfd) == bfd_target_coff_flavour 77 && symcount > 0) 78 { 79 if (! parse_coff (abfd, syms, symcount, dhandle)) 80 return NULL; 81 found = TRUE; 82 } 83 84 if (! found) 85 { 86 if (! no_messages) 87 non_fatal (_("%s: no recognized debugging information"), 88 bfd_get_filename (abfd)); 89 return NULL; 90 } 91 92 return dhandle; 93 } 94 95 /* Read stabs in sections debugging information from a BFD. */ 96 97 static bfd_boolean 98 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount, 99 void *dhandle, bfd_boolean *pfound) 100 { 101 static struct 102 { 103 const char *secname; 104 const char *strsecname; 105 } 106 names[] = 107 { 108 { ".stab", ".stabstr" }, 109 { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" }, 110 { "$GDB_SYMBOLS$", "$GDB_STRINGS$" } 111 }; 112 unsigned int i; 113 void *shandle; 114 115 *pfound = FALSE; 116 shandle = NULL; 117 118 for (i = 0; i < sizeof names / sizeof names[0]; i++) 119 { 120 asection *sec, *strsec; 121 122 sec = bfd_get_section_by_name (abfd, names[i].secname); 123 strsec = bfd_get_section_by_name (abfd, names[i].strsecname); 124 if (sec != NULL && strsec != NULL) 125 { 126 bfd_size_type stabsize, strsize; 127 bfd_byte *stabs, *strings; 128 bfd_byte *stab; 129 bfd_size_type stroff, next_stroff; 130 131 stabsize = bfd_section_size (abfd, sec); 132 stabs = (bfd_byte *) xmalloc (stabsize); 133 if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize)) 134 { 135 fprintf (stderr, "%s: %s: %s\n", 136 bfd_get_filename (abfd), names[i].secname, 137 bfd_errmsg (bfd_get_error ())); 138 return FALSE; 139 } 140 141 strsize = bfd_section_size (abfd, strsec); 142 strings = (bfd_byte *) xmalloc (strsize + 1); 143 if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize)) 144 { 145 fprintf (stderr, "%s: %s: %s\n", 146 bfd_get_filename (abfd), names[i].strsecname, 147 bfd_errmsg (bfd_get_error ())); 148 return FALSE; 149 } 150 /* Zero terminate the strings table, just in case. */ 151 strings [strsize] = 0; 152 if (shandle == NULL) 153 { 154 shandle = start_stab (dhandle, abfd, TRUE, syms, symcount); 155 if (shandle == NULL) 156 return FALSE; 157 } 158 159 *pfound = TRUE; 160 161 stroff = 0; 162 next_stroff = 0; 163 /* PR 17512: file: 078-60391-0.001:0.1. */ 164 for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12) 165 { 166 unsigned int strx; 167 int type; 168 int other ATTRIBUTE_UNUSED; 169 int desc; 170 bfd_vma value; 171 172 /* This code presumes 32 bit values. */ 173 174 strx = bfd_get_32 (abfd, stab); 175 type = bfd_get_8 (abfd, stab + 4); 176 other = bfd_get_8 (abfd, stab + 5); 177 desc = bfd_get_16 (abfd, stab + 6); 178 value = bfd_get_32 (abfd, stab + 8); 179 180 if (type == 0) 181 { 182 /* Special type 0 stabs indicate the offset to the 183 next string table. */ 184 stroff = next_stroff; 185 next_stroff += value; 186 } 187 else 188 { 189 size_t len; 190 char *f, *s; 191 192 if (stroff + strx >= strsize) 193 { 194 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"), 195 bfd_get_filename (abfd), names[i].secname, 196 (long) (stab - stabs) / 12, strx, type); 197 continue; 198 } 199 200 s = (char *) strings + stroff + strx; 201 f = NULL; 202 203 /* PR 17512: file: 002-87578-0.001:0.1. 204 It is possible to craft a file where, without the 'strlen (s) > 0', 205 an attempt to read the byte before 'strings' would occur. */ 206 while ((len = strlen (s)) > 0 207 && s[len - 1] == '\\' 208 && stab + 12 < stabs + stabsize) 209 { 210 char *p; 211 212 stab += 12; 213 p = s + len - 1; 214 *p = '\0'; 215 strx = stroff + bfd_get_32 (abfd, stab); 216 if (strx >= strsize) 217 { 218 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"), 219 bfd_get_filename (abfd), names[i].secname, 220 (long) (stab - stabs) / 12); 221 break; 222 } 223 else 224 s = concat (s, (char *) strings + strx, 225 (const char *) NULL); 226 227 /* We have to restore the backslash, because, if 228 the linker is hashing stabs strings, we may 229 see the same string more than once. */ 230 *p = '\\'; 231 232 if (f != NULL) 233 free (f); 234 f = s; 235 } 236 237 save_stab (type, desc, value, s); 238 239 if (! parse_stab (dhandle, shandle, type, desc, value, s)) 240 { 241 stab_context (); 242 free_saved_stabs (); 243 return FALSE; 244 } 245 246 /* Don't free f, since I think the stabs code 247 expects strings to hang around. This should be 248 straightened out. FIXME. */ 249 } 250 } 251 252 free_saved_stabs (); 253 free (stabs); 254 255 /* Don't free strings, since I think the stabs code expects 256 the strings to hang around. This should be straightened 257 out. FIXME. */ 258 } 259 } 260 261 if (shandle != NULL) 262 { 263 if (! finish_stab (dhandle, shandle)) 264 return FALSE; 265 } 266 267 return TRUE; 268 } 269 270 /* Read stabs in the symbol table. */ 271 272 static bfd_boolean 273 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount, 274 void *dhandle, bfd_boolean *pfound) 275 { 276 void *shandle; 277 asymbol **ps, **symend; 278 279 shandle = NULL; 280 symend = syms + symcount; 281 for (ps = syms; ps < symend; ps++) 282 { 283 symbol_info i; 284 285 bfd_get_symbol_info (abfd, *ps, &i); 286 287 if (i.type == '-') 288 { 289 const char *s; 290 char *f; 291 292 if (shandle == NULL) 293 { 294 shandle = start_stab (dhandle, abfd, FALSE, syms, symcount); 295 if (shandle == NULL) 296 return FALSE; 297 } 298 299 *pfound = TRUE; 300 301 s = i.name; 302 f = NULL; 303 while (s[strlen (s) - 1] == '\\' 304 && ps + 1 < symend) 305 { 306 char *sc, *n; 307 308 ++ps; 309 sc = xstrdup (s); 310 sc[strlen (sc) - 1] = '\0'; 311 n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL); 312 free (sc); 313 if (f != NULL) 314 free (f); 315 f = n; 316 s = n; 317 } 318 319 save_stab (i.stab_type, i.stab_desc, i.value, s); 320 321 if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc, 322 i.value, s)) 323 { 324 stab_context (); 325 free_saved_stabs (); 326 return FALSE; 327 } 328 329 /* Don't free f, since I think the stabs code expects 330 strings to hang around. This should be straightened out. 331 FIXME. */ 332 } 333 } 334 335 free_saved_stabs (); 336 337 if (shandle != NULL) 338 { 339 if (! finish_stab (dhandle, shandle)) 340 return FALSE; 341 } 342 343 return TRUE; 344 } 345 346 /* Read IEEE debugging information. */ 347 348 static bfd_boolean 349 read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound) 350 { 351 asection *dsec; 352 bfd_size_type size; 353 bfd_byte *contents; 354 355 /* The BFD backend puts the debugging information into a section 356 named .debug. */ 357 358 dsec = bfd_get_section_by_name (abfd, ".debug"); 359 if (dsec == NULL) 360 return TRUE; 361 362 size = bfd_section_size (abfd, dsec); 363 contents = (bfd_byte *) xmalloc (size); 364 if (! bfd_get_section_contents (abfd, dsec, contents, 0, size)) 365 return FALSE; 366 367 if (! parse_ieee (dhandle, abfd, contents, size)) 368 return FALSE; 369 370 free (contents); 371 372 *pfound = TRUE; 373 374 return TRUE; 375 } 376 377 /* Record stabs strings, so that we can give some context for errors. */ 378 379 #define SAVE_STABS_COUNT (16) 380 381 struct saved_stab 382 { 383 int type; 384 int desc; 385 bfd_vma value; 386 char *string; 387 }; 388 389 static struct saved_stab saved_stabs[SAVE_STABS_COUNT]; 390 static int saved_stabs_index; 391 392 /* Save a stabs string. */ 393 394 static void 395 save_stab (int type, int desc, bfd_vma value, const char *string) 396 { 397 if (saved_stabs[saved_stabs_index].string != NULL) 398 free (saved_stabs[saved_stabs_index].string); 399 saved_stabs[saved_stabs_index].type = type; 400 saved_stabs[saved_stabs_index].desc = desc; 401 saved_stabs[saved_stabs_index].value = value; 402 saved_stabs[saved_stabs_index].string = xstrdup (string); 403 saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT; 404 } 405 406 /* Provide context for an error. */ 407 408 static void 409 stab_context (void) 410 { 411 int i; 412 413 fprintf (stderr, _("Last stabs entries before error:\n")); 414 fprintf (stderr, "n_type n_desc n_value string\n"); 415 416 i = saved_stabs_index; 417 do 418 { 419 struct saved_stab *stabp; 420 421 stabp = saved_stabs + i; 422 if (stabp->string != NULL) 423 { 424 const char *s; 425 426 s = bfd_get_stab_name (stabp->type); 427 if (s != NULL) 428 fprintf (stderr, "%-6s", s); 429 else if (stabp->type == 0) 430 fprintf (stderr, "HdrSym"); 431 else 432 fprintf (stderr, "%-6d", stabp->type); 433 fprintf (stderr, " %-6d ", stabp->desc); 434 fprintf_vma (stderr, stabp->value); 435 if (stabp->type != 0) 436 fprintf (stderr, " %s", stabp->string); 437 fprintf (stderr, "\n"); 438 } 439 i = (i + 1) % SAVE_STABS_COUNT; 440 } 441 while (i != saved_stabs_index); 442 } 443 444 /* Free the saved stab strings. */ 445 446 static void 447 free_saved_stabs (void) 448 { 449 int i; 450 451 for (i = 0; i < SAVE_STABS_COUNT; i++) 452 { 453 if (saved_stabs[i].string != NULL) 454 { 455 free (saved_stabs[i].string); 456 saved_stabs[i].string = NULL; 457 } 458 } 459 460 saved_stabs_index = 0; 461 } 462