binutils/rddbg.c

   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               free (f);
 323               f = n;
 324               s = n;
 325             }
 326
 327           save_stab (i.stab_type, i.stab_desc, i.value, s);
 328
 329           if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
 330                             i.value, s))
 331             {
 332               stab_context ();
 333               free_saved_stabs ();
 334               return FALSE;
 335             }
 336
 337           /* Don't free f, since I think the stabs code expects
 338              strings to hang around.  This should be straightened out.
 339              FIXME.  */
 340         }
 341     }
 342
 343   free_saved_stabs ();
 344
 345   if (shandle != NULL)
 346     {
 347       if (! finish_stab (dhandle, shandle))
 348         return FALSE;
 349     }
 350
 351   return TRUE;
 352 }
 353 \f
 354 /* Record stabs strings, so that we can give some context for errors.  */
 355
 356 #define SAVE_STABS_COUNT (16)
 357
 358 struct saved_stab
 359 {
 360   int type;
 361   int desc;
 362   bfd_vma value;
 363   char *string;
 364 };
 365
 366 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 367 static int saved_stabs_index;
 368
 369 /* Save a stabs string.  */
 370
 371 static void
 372 save_stab (int type, int desc, bfd_vma value, const char *string)
 373 {
 374   free (saved_stabs[saved_stabs_index].string);
 375   saved_stabs[saved_stabs_index].type = type;
 376   saved_stabs[saved_stabs_index].desc = desc;
 377   saved_stabs[saved_stabs_index].value = value;
 378   saved_stabs[saved_stabs_index].string = xstrdup (string);
 379   saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
 380 }
 381
 382 /* Provide context for an error.  */
 383
 384 static void
 385 stab_context (void)
 386 {
 387   int i;
 388
 389   fprintf (stderr, _("Last stabs entries before error:\n"));
 390   fprintf (stderr, "n_type n_desc n_value  string\n");
 391
 392   i = saved_stabs_index;
 393   do
 394     {
 395       struct saved_stab *stabp;
 396
 397       stabp = saved_stabs + i;
 398       if (stabp->string != NULL)
 399         {
 400           const char *s;
 401
 402           s = bfd_get_stab_name (stabp->type);
 403           if (s != NULL)
 404             fprintf (stderr, "%-6s", s);
 405           else if (stabp->type == 0)
 406             fprintf (stderr, "HdrSym");
 407           else
 408             fprintf (stderr, "%-6d", stabp->type);
 409           fprintf (stderr, " %-6d ", stabp->desc);
 410           fprintf_vma (stderr, stabp->value);
 411           if (stabp->type != 0)
 412             fprintf (stderr, " %s", stabp->string);
 413           fprintf (stderr, "\n");
 414         }
 415       i = (i + 1) % SAVE_STABS_COUNT;
 416     }
 417   while (i != saved_stabs_index);
 418 }
 419
 420 /* Free the saved stab strings.  */
 421
 422 static void
 423 free_saved_stabs (void)
 424 {
 425   int i;
 426
 427   for (i = 0; i < SAVE_STABS_COUNT; i++)
 428     {
 429       free (saved_stabs[i].string);
 430       saved_stabs[i].string = NULL;
 431     }
 432
 433   saved_stabs_index = 0;
 434 }