binutils/rddbg.c

   1 /* rddbg.c -- Read debugging information into a generic form.
   2    Copyright (C) 1995-2023 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 bool read_section_stabs_debugging_info
  35   (bfd *, asymbol **, long, void *, bool *);
  36 static bool read_symbol_stabs_debugging_info
  37   (bfd *, asymbol **, long, void *, bool *);
  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,
  47                      bool no_messages)
  48 {
  49   void *dhandle;
  50   bool 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     goto err_exit;
  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         goto err_exit;
  65     }
  66
  67   /* Try reading the COFF symbols if we didn't find any stabs in COFF
  68      sections.  */
  69   if (! found
  70       && bfd_get_flavour (abfd) == bfd_target_coff_flavour
  71       && symcount > 0)
  72     {
  73       if (! parse_coff (abfd, syms, symcount, dhandle))
  74         goto err_exit;
  75       found = true;
  76     }
  77
  78   if (! found)
  79     {
  80       if (! no_messages)
  81         non_fatal (_("%s: no recognized debugging information"),
  82                    bfd_get_filename (abfd));
  83     err_exit:
  84       free (dhandle);
  85       return NULL;
  86     }
  87
  88   return dhandle;
  89 }
  90
  91 /* Read stabs in sections debugging information from a BFD.  */
  92
  93 static bool
  94 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
  95                                    void *dhandle, bool *pfound)
  96 {
  97   static struct
  98     {
  99       const char *secname;
 100       const char *strsecname;
 101     }
 102   names[] =
 103     {
 104       { ".stab", ".stabstr" },
 105       { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
 106       { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
 107     };
 108   unsigned int i;
 109   void *shandle;
 110
 111   *pfound = false;
 112   shandle = NULL;
 113
 114   for (i = 0; i < sizeof names / sizeof names[0]; i++)
 115     {
 116       asection *sec, *strsec;
 117
 118       sec = bfd_get_section_by_name (abfd, names[i].secname);
 119       strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
 120       if (sec != NULL
 121           && (bfd_section_flags (sec) & SEC_HAS_CONTENTS) != 0
 122           && strsec != NULL
 123           && (bfd_section_flags (strsec) & SEC_HAS_CONTENTS) != 0)
 124         {
 125           bfd_size_type stabsize, strsize;
 126           bfd_byte *stabs, *strings;
 127           bfd_byte *stab;
 128           bfd_size_type stroff, next_stroff;
 129
 130           if (!bfd_malloc_and_get_section (abfd, sec, &stabs))
 131             {
 132               fprintf (stderr, "%s: %s: %s\n",
 133                        bfd_get_filename (abfd), names[i].secname,
 134                        bfd_errmsg (bfd_get_error ()));
 135               free (shandle);
 136               return false;
 137             }
 138
 139           if (!bfd_malloc_and_get_section (abfd, strsec, &strings))
 140             {
 141               fprintf (stderr, "%s: %s: %s\n",
 142                        bfd_get_filename (abfd), names[i].strsecname,
 143                        bfd_errmsg (bfd_get_error ()));
 144               free (shandle);
 145               free (stabs);
 146               return false;
 147             }
 148           /* Zero terminate the strings table, just in case.  */
 149           strsize = bfd_section_size (strsec);
 150           strings [strsize - 1] = 0;
 151           if (shandle == NULL)
 152             {
 153               shandle = start_stab (dhandle, abfd, true, syms, symcount);
 154               if (shandle == NULL)
 155                 {
 156                   free (strings);
 157                   free (stabs);
 158                   return false;
 159                 }
 160             }
 161
 162           *pfound = true;
 163
 164           stroff = 0;
 165           next_stroff = 0;
 166           stabsize = bfd_section_size (sec);
 167           /* PR 17512: file: 078-60391-0.001:0.1.  */
 168           for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12)
 169             {
 170               unsigned int strx;
 171               int type;
 172               int other ATTRIBUTE_UNUSED;
 173               int desc;
 174               bfd_vma value;
 175
 176               /* This code presumes 32 bit values.  */
 177
 178               strx = bfd_get_32 (abfd, stab);
 179               type = bfd_get_8 (abfd, stab + 4);
 180               other = bfd_get_8 (abfd, stab + 5);
 181               desc = bfd_get_16 (abfd, stab + 6);
 182               value = bfd_get_32 (abfd, stab + 8);
 183
 184               if (type == 0)
 185                 {
 186                   /* Special type 0 stabs indicate the offset to the
 187                      next string table.  */
 188                   stroff = next_stroff;
 189                   next_stroff += value;
 190                 }
 191               else
 192                 {
 193                   size_t len;
 194                   char *f, *s;
 195
 196                   if (stroff + strx >= strsize)
 197                     {
 198                       fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"),
 199                                bfd_get_filename (abfd), names[i].secname,
 200                                (long) (stab - stabs) / 12, strx, type);
 201                       continue;
 202                     }
 203
 204                   s = (char *) strings + stroff + strx;
 205                   f = NULL;
 206
 207                   /* PR 17512: file: 002-87578-0.001:0.1.
 208                      It is possible to craft a file where, without the 'strlen (s) > 0',
 209                      an attempt to read the byte before 'strings' would occur.  */
 210                   while ((len = strlen (s)) > 0
 211                          && s[len  - 1] == '\\'
 212                          && stab + 16 <= stabs + stabsize)
 213                     {
 214                       char *p;
 215
 216                       stab += 12;
 217                       p = s + len - 1;
 218                       *p = '\0';
 219                       strx = stroff + bfd_get_32 (abfd, stab);
 220                       if (strx >= strsize)
 221                         {
 222                           fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"),
 223                                    bfd_get_filename (abfd), names[i].secname,
 224                                    (long) (stab - stabs) / 12);
 225                           break;
 226                         }
 227
 228                       s = concat (s, (char *) strings + strx,
 229                                   (const char *) NULL);
 230
 231                       /* We have to restore the backslash, because, if
 232                          the linker is hashing stabs strings, we may
 233                          see the same string more than once.  */
 234                       *p = '\\';
 235
 236                       free (f);
 237                       f = s;
 238                     }
 239
 240                   save_stab (type, desc, value, s);
 241
 242                   if (! parse_stab (dhandle, shandle, type, desc, value, s))
 243                     {
 244                       stab_context ();
 245                       free_saved_stabs ();
 246                       free (f);
 247                       free (shandle);
 248                       free (stabs);
 249                       free (strings);
 250                       return false;
 251                     }
 252
 253                   /* Don't free f, since I think the stabs code
 254                      expects strings to hang around.  This should be
 255                      straightened out.  FIXME.  */
 256                 }
 257             }
 258
 259           free_saved_stabs ();
 260           free (stabs);
 261
 262           /* Don't free strings, since I think the stabs code expects
 263              the strings to hang around.  This should be straightened
 264              out.  FIXME.  */
 265         }
 266     }
 267
 268   if (shandle != NULL)
 269     {
 270       if (! finish_stab (dhandle, shandle))
 271         return false;
 272     }
 273
 274   return true;
 275 }
 276
 277 /* Read stabs in the symbol table.  */
 278
 279 static bool
 280 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
 281                                   void *dhandle, bool *pfound)
 282 {
 283   void *shandle;
 284   asymbol **ps, **symend;
 285
 286   shandle = NULL;
 287   symend = syms + symcount;
 288   for (ps = syms; ps < symend; ps++)
 289     {
 290       symbol_info i;
 291
 292       bfd_get_symbol_info (abfd, *ps, &i);
 293
 294       if (i.type == '-')
 295         {
 296           const char *s;
 297           char *f;
 298
 299           if (shandle == NULL)
 300             {
 301               shandle = start_stab (dhandle, abfd, false, syms, symcount);
 302               if (shandle == NULL)
 303                 return false;
 304             }
 305
 306           *pfound = true;
 307
 308           s = i.name;
 309           if (s == NULL || strlen (s) < 1)
 310             return false;
 311           f = NULL;
 312
 313           while (strlen (s) > 0
 314                  && s[strlen (s) - 1] == '\\'
 315                  && ps + 1 < symend)
 316             {
 317               char *sc, *n;
 318
 319               ++ps;
 320               sc = xstrdup (s);
 321               sc[strlen (sc) - 1] = '\0';
 322               n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
 323               free (sc);
 324               free (f);
 325               f = n;
 326               s = n;
 327             }
 328
 329           save_stab (i.stab_type, i.stab_desc, i.value, s);
 330
 331           if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
 332                             i.value, s))
 333             {
 334               stab_context ();
 335               free_saved_stabs ();
 336               return false;
 337             }
 338
 339           /* Don't free f, since I think the stabs code expects
 340              strings to hang around.  This should be straightened out.
 341              FIXME.  */
 342         }
 343     }
 344
 345   free_saved_stabs ();
 346
 347   if (shandle != NULL)
 348     {
 349       if (! finish_stab (dhandle, shandle))
 350         return false;
 351     }
 352
 353   return true;
 354 }
 355 \f
 356 /* Record stabs strings, so that we can give some context for errors.  */
 357
 358 #define SAVE_STABS_COUNT (16)
 359
 360 struct saved_stab
 361 {
 362   int type;
 363   int desc;
 364   bfd_vma value;
 365   char *string;
 366 };
 367
 368 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 369 static int saved_stabs_index;
 370
 371 /* Save a stabs string.  */
 372
 373 static void
 374 save_stab (int type, int desc, bfd_vma value, const char *string)
 375 {
 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 (stderr, "%08" PRIx64, (uint64_t) 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       free (saved_stabs[i].string);
 432       saved_stabs[i].string = NULL;
 433     }
 434
 435   saved_stabs_index = 0;
 436 }