1 /* rddbg.c -- Read debugging information into a generic form. 2 Copyright (C) 1995-2020 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 void save_stab (int, int, bfd_vma, const char *); 39 static void stab_context (void); 40 static void free_saved_stabs (void); 41 42 /* Read debugging information from a BFD. Returns a generic debugging 43 pointer. */ 44 45 void * 46 read_debugging_info (bfd *abfd, asymbol **syms, long symcount, bfd_boolean no_messages) 47 { 48 void *dhandle; 49 bfd_boolean found; 50 51 dhandle = debug_init (); 52 if (dhandle == NULL) 53 return NULL; 54 55 if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle, 56 &found)) 57 return NULL; 58 59 if (bfd_get_flavour (abfd) == bfd_target_aout_flavour) 60 { 61 if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle, 62 &found)) 63 return NULL; 64 } 65 66 /* Try reading the COFF symbols if we didn't find any stabs in COFF 67 sections. */ 68 if (! found 69 && bfd_get_flavour (abfd) == bfd_target_coff_flavour 70 && symcount > 0) 71 { 72 if (! parse_coff (abfd, syms, symcount, dhandle)) 73 return NULL; 74 found = TRUE; 75 } 76 77 if (! found) 78 { 79 if (! no_messages) 80 non_fatal (_("%s: no recognized debugging information"), 81 bfd_get_filename (abfd)); 82 return NULL; 83 } 84 85 return dhandle; 86 } 87 88 /* Read stabs in sections debugging information from a BFD. */ 89 90 static bfd_boolean 91 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount, 92 void *dhandle, bfd_boolean *pfound) 93 { 94 static struct 95 { 96 const char *secname; 97 const char *strsecname; 98 } 99 names[] = 100 { 101 { ".stab", ".stabstr" }, 102 { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" }, 103 { "$GDB_SYMBOLS$", "$GDB_STRINGS$" } 104 }; 105 unsigned int i; 106 void *shandle; 107 108 *pfound = FALSE; 109 shandle = NULL; 110 111 for (i = 0; i < sizeof names / sizeof names[0]; i++) 112 { 113 asection *sec, *strsec; 114 115 sec = bfd_get_section_by_name (abfd, names[i].secname); 116 strsec = bfd_get_section_by_name (abfd, names[i].strsecname); 117 if (sec != NULL && strsec != NULL) 118 { 119 bfd_size_type stabsize, strsize; 120 bfd_byte *stabs, *strings; 121 bfd_byte *stab; 122 bfd_size_type stroff, next_stroff; 123 124 stabsize = bfd_section_size (sec); 125 stabs = (bfd_byte *) xmalloc (stabsize); 126 if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize)) 127 { 128 fprintf (stderr, "%s: %s: %s\n", 129 bfd_get_filename (abfd), names[i].secname, 130 bfd_errmsg (bfd_get_error ())); 131 free (shandle); 132 free (stabs); 133 return FALSE; 134 } 135 136 strsize = bfd_section_size (strsec); 137 strings = (bfd_byte *) xmalloc (strsize + 1); 138 if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize)) 139 { 140 fprintf (stderr, "%s: %s: %s\n", 141 bfd_get_filename (abfd), names[i].strsecname, 142 bfd_errmsg (bfd_get_error ())); 143 free (shandle); 144 free (strings); 145 free (stabs); 146 return FALSE; 147 } 148 /* Zero terminate the strings table, just in case. */ 149 strings [strsize] = 0; 150 if (shandle == NULL) 151 { 152 shandle = start_stab (dhandle, abfd, TRUE, syms, symcount); 153 if (shandle == NULL) 154 { 155 free (strings); 156 free (stabs); 157 return FALSE; 158 } 159 } 160 161 *pfound = TRUE; 162 163 stroff = 0; 164 next_stroff = 0; 165 /* PR 17512: file: 078-60391-0.001:0.1. */ 166 for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12) 167 { 168 unsigned int strx; 169 int type; 170 int other ATTRIBUTE_UNUSED; 171 int desc; 172 bfd_vma value; 173 174 /* This code presumes 32 bit values. */ 175 176 strx = bfd_get_32 (abfd, stab); 177 type = bfd_get_8 (abfd, stab + 4); 178 other = bfd_get_8 (abfd, stab + 5); 179 desc = bfd_get_16 (abfd, stab + 6); 180 value = bfd_get_32 (abfd, stab + 8); 181 182 if (type == 0) 183 { 184 /* Special type 0 stabs indicate the offset to the 185 next string table. */ 186 stroff = next_stroff; 187 next_stroff += value; 188 } 189 else 190 { 191 size_t len; 192 char *f, *s; 193 194 if (stroff + strx >= strsize) 195 { 196 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"), 197 bfd_get_filename (abfd), names[i].secname, 198 (long) (stab - stabs) / 12, strx, type); 199 continue; 200 } 201 202 s = (char *) strings + stroff + strx; 203 f = NULL; 204 205 /* PR 17512: file: 002-87578-0.001:0.1. 206 It is possible to craft a file where, without the 'strlen (s) > 0', 207 an attempt to read the byte before 'strings' would occur. */ 208 while ((len = strlen (s)) > 0 209 && s[len - 1] == '\\' 210 && stab + 12 < stabs + stabsize) 211 { 212 char *p; 213 214 stab += 12; 215 p = s + len - 1; 216 *p = '\0'; 217 strx = stroff + bfd_get_32 (abfd, stab); 218 if (strx >= strsize) 219 { 220 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"), 221 bfd_get_filename (abfd), names[i].secname, 222 (long) (stab - stabs) / 12); 223 break; 224 } 225 226 s = concat (s, (char *) strings + strx, 227 (const char *) NULL); 228 229 /* We have to restore the backslash, because, if 230 the linker is hashing stabs strings, we may 231 see the same string more than once. */ 232 *p = '\\'; 233 234 free (f); 235 f = s; 236 } 237 238 save_stab (type, desc, value, s); 239 240 if (! parse_stab (dhandle, shandle, type, desc, value, s)) 241 { 242 stab_context (); 243 free_saved_stabs (); 244 free (f); 245 free (shandle); 246 free (stabs); 247 free (strings); 248 return FALSE; 249 } 250 251 /* Don't free f, since I think the stabs code 252 expects strings to hang around. This should be 253 straightened out. FIXME. */ 254 } 255 } 256 257 free_saved_stabs (); 258 free (stabs); 259 260 /* Don't free strings, since I think the stabs code expects 261 the strings to hang around. This should be straightened 262 out. FIXME. */ 263 } 264 } 265 266 if (shandle != NULL) 267 { 268 if (! finish_stab (dhandle, shandle)) 269 return FALSE; 270 } 271 272 return TRUE; 273 } 274 275 /* Read stabs in the symbol table. */ 276 277 static bfd_boolean 278 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount, 279 void *dhandle, bfd_boolean *pfound) 280 { 281 void *shandle; 282 asymbol **ps, **symend; 283 284 shandle = NULL; 285 symend = syms + symcount; 286 for (ps = syms; ps < symend; ps++) 287 { 288 symbol_info i; 289 290 bfd_get_symbol_info (abfd, *ps, &i); 291 292 if (i.type == '-') 293 { 294 const char *s; 295 char *f; 296 297 if (shandle == NULL) 298 { 299 shandle = start_stab (dhandle, abfd, FALSE, syms, symcount); 300 if (shandle == NULL) 301 return FALSE; 302 } 303 304 *pfound = TRUE; 305 306 s = i.name; 307 if (s == NULL || strlen (s) < 1) 308 return FALSE; 309 f = NULL; 310 311 while (strlen (s) > 0 312 && s[strlen (s) - 1] == '\\' 313 && ps + 1 < symend) 314 { 315 char *sc, *n; 316 317 ++ps; 318 sc = xstrdup (s); 319 sc[strlen (sc) - 1] = '\0'; 320 n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL); 321 free (sc); 322 if (f != NULL) 323 free (f); 324 f = n; 325 s = n; 326 } 327 328 save_stab (i.stab_type, i.stab_desc, i.value, s); 329 330 if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc, 331 i.value, s)) 332 { 333 stab_context (); 334 free_saved_stabs (); 335 return FALSE; 336 } 337 338 /* Don't free f, since I think the stabs code expects 339 strings to hang around. This should be straightened out. 340 FIXME. */ 341 } 342 } 343 344 free_saved_stabs (); 345 346 if (shandle != NULL) 347 { 348 if (! finish_stab (dhandle, shandle)) 349 return FALSE; 350 } 351 352 return TRUE; 353 } 354 355 /* Record stabs strings, so that we can give some context for errors. */ 356 357 #define SAVE_STABS_COUNT (16) 358 359 struct saved_stab 360 { 361 int type; 362 int desc; 363 bfd_vma value; 364 char *string; 365 }; 366 367 static struct saved_stab saved_stabs[SAVE_STABS_COUNT]; 368 static int saved_stabs_index; 369 370 /* Save a stabs string. */ 371 372 static void 373 save_stab (int type, int desc, bfd_vma value, const char *string) 374 { 375 if (saved_stabs[saved_stabs_index].string != NULL) 376 free (saved_stabs[saved_stabs_index].string); 377 saved_stabs[saved_stabs_index].type = type; 378 saved_stabs[saved_stabs_index].desc = desc; 379 saved_stabs[saved_stabs_index].value = value; 380 saved_stabs[saved_stabs_index].string = xstrdup (string); 381 saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT; 382 } 383 384 /* Provide context for an error. */ 385 386 static void 387 stab_context (void) 388 { 389 int i; 390 391 fprintf (stderr, _("Last stabs entries before error:\n")); 392 fprintf (stderr, "n_type n_desc n_value string\n"); 393 394 i = saved_stabs_index; 395 do 396 { 397 struct saved_stab *stabp; 398 399 stabp = saved_stabs + i; 400 if (stabp->string != NULL) 401 { 402 const char *s; 403 404 s = bfd_get_stab_name (stabp->type); 405 if (s != NULL) 406 fprintf (stderr, "%-6s", s); 407 else if (stabp->type == 0) 408 fprintf (stderr, "HdrSym"); 409 else 410 fprintf (stderr, "%-6d", stabp->type); 411 fprintf (stderr, " %-6d ", stabp->desc); 412 fprintf_vma (stderr, stabp->value); 413 if (stabp->type != 0) 414 fprintf (stderr, " %s", stabp->string); 415 fprintf (stderr, "\n"); 416 } 417 i = (i + 1) % SAVE_STABS_COUNT; 418 } 419 while (i != saved_stabs_index); 420 } 421 422 /* Free the saved stab strings. */ 423 424 static void 425 free_saved_stabs (void) 426 { 427 int i; 428 429 for (i = 0; i < SAVE_STABS_COUNT; i++) 430 { 431 if (saved_stabs[i].string != NULL) 432 { 433 free (saved_stabs[i].string); 434 saved_stabs[i].string = NULL; 435 } 436 } 437 438 saved_stabs_index = 0; 439 } 440