1 /* rddbg.c -- Read debugging information into a generic form. 2 Copyright (C) 1995-2018 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 (abfd, 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 return FALSE; 132 } 133 134 strsize = bfd_section_size (abfd, strsec); 135 strings = (bfd_byte *) xmalloc (strsize + 1); 136 if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize)) 137 { 138 fprintf (stderr, "%s: %s: %s\n", 139 bfd_get_filename (abfd), names[i].strsecname, 140 bfd_errmsg (bfd_get_error ())); 141 return FALSE; 142 } 143 /* Zero terminate the strings table, just in case. */ 144 strings [strsize] = 0; 145 if (shandle == NULL) 146 { 147 shandle = start_stab (dhandle, abfd, TRUE, syms, symcount); 148 if (shandle == NULL) 149 return FALSE; 150 } 151 152 *pfound = TRUE; 153 154 stroff = 0; 155 next_stroff = 0; 156 /* PR 17512: file: 078-60391-0.001:0.1. */ 157 for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12) 158 { 159 unsigned int strx; 160 int type; 161 int other ATTRIBUTE_UNUSED; 162 int desc; 163 bfd_vma value; 164 165 /* This code presumes 32 bit values. */ 166 167 strx = bfd_get_32 (abfd, stab); 168 type = bfd_get_8 (abfd, stab + 4); 169 other = bfd_get_8 (abfd, stab + 5); 170 desc = bfd_get_16 (abfd, stab + 6); 171 value = bfd_get_32 (abfd, stab + 8); 172 173 if (type == 0) 174 { 175 /* Special type 0 stabs indicate the offset to the 176 next string table. */ 177 stroff = next_stroff; 178 next_stroff += value; 179 } 180 else 181 { 182 size_t len; 183 char *f, *s; 184 185 if (stroff + strx >= strsize) 186 { 187 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"), 188 bfd_get_filename (abfd), names[i].secname, 189 (long) (stab - stabs) / 12, strx, type); 190 continue; 191 } 192 193 s = (char *) strings + stroff + strx; 194 f = NULL; 195 196 /* PR 17512: file: 002-87578-0.001:0.1. 197 It is possible to craft a file where, without the 'strlen (s) > 0', 198 an attempt to read the byte before 'strings' would occur. */ 199 while ((len = strlen (s)) > 0 200 && s[len - 1] == '\\' 201 && stab + 12 < stabs + stabsize) 202 { 203 char *p; 204 205 stab += 12; 206 p = s + len - 1; 207 *p = '\0'; 208 strx = stroff + bfd_get_32 (abfd, stab); 209 if (strx >= strsize) 210 { 211 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"), 212 bfd_get_filename (abfd), names[i].secname, 213 (long) (stab - stabs) / 12); 214 break; 215 } 216 else 217 s = concat (s, (char *) strings + strx, 218 (const char *) NULL); 219 220 /* We have to restore the backslash, because, if 221 the linker is hashing stabs strings, we may 222 see the same string more than once. */ 223 *p = '\\'; 224 225 if (f != NULL) 226 free (f); 227 f = s; 228 } 229 230 save_stab (type, desc, value, s); 231 232 if (! parse_stab (dhandle, shandle, type, desc, value, s)) 233 { 234 stab_context (); 235 free_saved_stabs (); 236 return FALSE; 237 } 238 239 /* Don't free f, since I think the stabs code 240 expects strings to hang around. This should be 241 straightened out. FIXME. */ 242 } 243 } 244 245 free_saved_stabs (); 246 free (stabs); 247 248 /* Don't free strings, since I think the stabs code expects 249 the strings to hang around. This should be straightened 250 out. FIXME. */ 251 } 252 } 253 254 if (shandle != NULL) 255 { 256 if (! finish_stab (dhandle, shandle)) 257 return FALSE; 258 } 259 260 return TRUE; 261 } 262 263 /* Read stabs in the symbol table. */ 264 265 static bfd_boolean 266 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount, 267 void *dhandle, bfd_boolean *pfound) 268 { 269 void *shandle; 270 asymbol **ps, **symend; 271 272 shandle = NULL; 273 symend = syms + symcount; 274 for (ps = syms; ps < symend; ps++) 275 { 276 symbol_info i; 277 278 bfd_get_symbol_info (abfd, *ps, &i); 279 280 if (i.type == '-') 281 { 282 const char *s; 283 char *f; 284 285 if (shandle == NULL) 286 { 287 shandle = start_stab (dhandle, abfd, FALSE, syms, symcount); 288 if (shandle == NULL) 289 return FALSE; 290 } 291 292 *pfound = TRUE; 293 294 s = i.name; 295 if (s == NULL || strlen (s) < 1) 296 return FALSE; 297 f = NULL; 298 299 while (strlen (s) > 0 300 && s[strlen (s) - 1] == '\\' 301 && ps + 1 < symend) 302 { 303 char *sc, *n; 304 305 ++ps; 306 sc = xstrdup (s); 307 sc[strlen (sc) - 1] = '\0'; 308 n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL); 309 free (sc); 310 if (f != NULL) 311 free (f); 312 f = n; 313 s = n; 314 } 315 316 save_stab (i.stab_type, i.stab_desc, i.value, s); 317 318 if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc, 319 i.value, s)) 320 { 321 stab_context (); 322 free_saved_stabs (); 323 return FALSE; 324 } 325 326 /* Don't free f, since I think the stabs code expects 327 strings to hang around. This should be straightened out. 328 FIXME. */ 329 } 330 } 331 332 free_saved_stabs (); 333 334 if (shandle != NULL) 335 { 336 if (! finish_stab (dhandle, shandle)) 337 return FALSE; 338 } 339 340 return TRUE; 341 } 342 343 /* Record stabs strings, so that we can give some context for errors. */ 344 345 #define SAVE_STABS_COUNT (16) 346 347 struct saved_stab 348 { 349 int type; 350 int desc; 351 bfd_vma value; 352 char *string; 353 }; 354 355 static struct saved_stab saved_stabs[SAVE_STABS_COUNT]; 356 static int saved_stabs_index; 357 358 /* Save a stabs string. */ 359 360 static void 361 save_stab (int type, int desc, bfd_vma value, const char *string) 362 { 363 if (saved_stabs[saved_stabs_index].string != NULL) 364 free (saved_stabs[saved_stabs_index].string); 365 saved_stabs[saved_stabs_index].type = type; 366 saved_stabs[saved_stabs_index].desc = desc; 367 saved_stabs[saved_stabs_index].value = value; 368 saved_stabs[saved_stabs_index].string = xstrdup (string); 369 saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT; 370 } 371 372 /* Provide context for an error. */ 373 374 static void 375 stab_context (void) 376 { 377 int i; 378 379 fprintf (stderr, _("Last stabs entries before error:\n")); 380 fprintf (stderr, "n_type n_desc n_value string\n"); 381 382 i = saved_stabs_index; 383 do 384 { 385 struct saved_stab *stabp; 386 387 stabp = saved_stabs + i; 388 if (stabp->string != NULL) 389 { 390 const char *s; 391 392 s = bfd_get_stab_name (stabp->type); 393 if (s != NULL) 394 fprintf (stderr, "%-6s", s); 395 else if (stabp->type == 0) 396 fprintf (stderr, "HdrSym"); 397 else 398 fprintf (stderr, "%-6d", stabp->type); 399 fprintf (stderr, " %-6d ", stabp->desc); 400 fprintf_vma (stderr, stabp->value); 401 if (stabp->type != 0) 402 fprintf (stderr, " %s", stabp->string); 403 fprintf (stderr, "\n"); 404 } 405 i = (i + 1) % SAVE_STABS_COUNT; 406 } 407 while (i != saved_stabs_index); 408 } 409 410 /* Free the saved stab strings. */ 411 412 static void 413 free_saved_stabs (void) 414 { 415 int i; 416 417 for (i = 0; i < SAVE_STABS_COUNT; i++) 418 { 419 if (saved_stabs[i].string != NULL) 420 { 421 free (saved_stabs[i].string); 422 saved_stabs[i].string = NULL; 423 } 424 } 425 426 saved_stabs_index = 0; 427 } 428