binutils/rddbg.c

   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 \f
 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 }