binutils/rddbg.c

   1 /* rddbg.c -- Read debugging information into a generic form.
   2    Copyright (C) 1995-2017 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 bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
  39 static void save_stab (int, int, bfd_vma, const char *);
  40 static void stab_context (void);
  41 static void free_saved_stabs (void);
  42
  43 /* Read debugging information from a BFD.  Returns a generic debugging
  44    pointer.  */
  45
  46 void *
  47 read_debugging_info (bfd *abfd, asymbol **syms, long symcount, bfd_boolean no_messages)
  48 {
  49   void *dhandle;
  50   bfd_boolean 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     return NULL;
  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         return NULL;
  65     }
  66
  67   if (bfd_get_flavour (abfd) == bfd_target_ieee_flavour)
  68     {
  69       if (! read_ieee_debugging_info (abfd, dhandle, &found))
  70         return NULL;
  71     }
  72
  73   /* Try reading the COFF symbols if we didn't find any stabs in COFF
  74      sections.  */
  75   if (! found
  76       && bfd_get_flavour (abfd) == bfd_target_coff_flavour
  77       && symcount > 0)
  78     {
  79       if (! parse_coff (abfd, syms, symcount, dhandle))
  80         return NULL;
  81       found = TRUE;
  82     }
  83
  84   if (! found)
  85     {
  86       if (! no_messages)
  87         non_fatal (_("%s: no recognized debugging information"),
  88                    bfd_get_filename (abfd));
  89       return NULL;
  90     }
  91
  92   return dhandle;
  93 }
  94
  95 /* Read stabs in sections debugging information from a BFD.  */
  96
  97 static bfd_boolean
  98 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
  99                                    void *dhandle, bfd_boolean *pfound)
 100 {
 101   static struct
 102     {
 103       const char *secname;
 104       const char *strsecname;
 105     }
 106   names[] =
 107     {
 108       { ".stab", ".stabstr" },
 109       { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
 110       { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
 111     };
 112   unsigned int i;
 113   void *shandle;
 114
 115   *pfound = FALSE;
 116   shandle = NULL;
 117
 118   for (i = 0; i < sizeof names / sizeof names[0]; i++)
 119     {
 120       asection *sec, *strsec;
 121
 122       sec = bfd_get_section_by_name (abfd, names[i].secname);
 123       strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
 124       if (sec != NULL && strsec != NULL)
 125         {
 126           bfd_size_type stabsize, strsize;
 127           bfd_byte *stabs, *strings;
 128           bfd_byte *stab;
 129           bfd_size_type stroff, next_stroff;
 130
 131           stabsize = bfd_section_size (abfd, sec);
 132           stabs = (bfd_byte *) xmalloc (stabsize);
 133           if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
 134             {
 135               fprintf (stderr, "%s: %s: %s\n",
 136                        bfd_get_filename (abfd), names[i].secname,
 137                        bfd_errmsg (bfd_get_error ()));
 138               return FALSE;
 139             }
 140
 141           strsize = bfd_section_size (abfd, strsec);
 142           strings = (bfd_byte *) xmalloc (strsize + 1);
 143           if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
 144             {
 145               fprintf (stderr, "%s: %s: %s\n",
 146                        bfd_get_filename (abfd), names[i].strsecname,
 147                        bfd_errmsg (bfd_get_error ()));
 148               return FALSE;
 149             }
 150           /* Zero terminate the strings table, just in case.  */
 151           strings [strsize] = 0;
 152           if (shandle == NULL)
 153             {
 154               shandle = start_stab (dhandle, abfd, TRUE, syms, symcount);
 155               if (shandle == NULL)
 156                 return FALSE;
 157             }
 158
 159           *pfound = TRUE;
 160
 161           stroff = 0;
 162           next_stroff = 0;
 163           /* PR 17512: file: 078-60391-0.001:0.1.  */
 164           for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12)
 165             {
 166               unsigned int strx;
 167               int type;
 168               int other ATTRIBUTE_UNUSED;
 169               int desc;
 170               bfd_vma value;
 171
 172               /* This code presumes 32 bit values.  */
 173
 174               strx = bfd_get_32 (abfd, stab);
 175               type = bfd_get_8 (abfd, stab + 4);
 176               other = bfd_get_8 (abfd, stab + 5);
 177               desc = bfd_get_16 (abfd, stab + 6);
 178               value = bfd_get_32 (abfd, stab + 8);
 179
 180               if (type == 0)
 181                 {
 182                   /* Special type 0 stabs indicate the offset to the
 183                      next string table.  */
 184                   stroff = next_stroff;
 185                   next_stroff += value;
 186                 }
 187               else
 188                 {
 189                   size_t len;
 190                   char *f, *s;
 191
 192                   if (stroff + strx >= strsize)
 193                     {
 194                       fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"),
 195                                bfd_get_filename (abfd), names[i].secname,
 196                                (long) (stab - stabs) / 12, strx, type);
 197                       continue;
 198                     }
 199
 200                   s = (char *) strings + stroff + strx;
 201                   f = NULL;
 202
 203                   /* PR 17512: file: 002-87578-0.001:0.1.
 204                      It is possible to craft a file where, without the 'strlen (s) > 0',
 205                      an attempt to read the byte before 'strings' would occur.  */
 206                   while ((len = strlen (s)) > 0
 207                          && s[len  - 1] == '\\'
 208                          && stab + 12 < stabs + stabsize)
 209                     {
 210                       char *p;
 211
 212                       stab += 12;
 213                       p = s + len - 1;
 214                       *p = '\0';
 215                       strx = stroff + bfd_get_32 (abfd, stab);
 216                       if (strx >= strsize)
 217                         {
 218                           fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"),
 219                                    bfd_get_filename (abfd), names[i].secname,
 220                                    (long) (stab - stabs) / 12);
 221                           break;
 222                         }
 223                       else
 224                         s = concat (s, (char *) strings + strx,
 225                                     (const char *) NULL);
 226
 227                       /* We have to restore the backslash, because, if
 228                          the linker is hashing stabs strings, we may
 229                          see the same string more than once.  */
 230                       *p = '\\';
 231
 232                       if (f != NULL)
 233                         free (f);
 234                       f = s;
 235                     }
 236
 237                   save_stab (type, desc, value, s);
 238
 239                   if (! parse_stab (dhandle, shandle, type, desc, value, s))
 240                     {
 241                       stab_context ();
 242                       free_saved_stabs ();
 243                       return FALSE;
 244                     }
 245
 246                   /* Don't free f, since I think the stabs code
 247                      expects strings to hang around.  This should be
 248                      straightened out.  FIXME.  */
 249                 }
 250             }
 251
 252           free_saved_stabs ();
 253           free (stabs);
 254
 255           /* Don't free strings, since I think the stabs code expects
 256              the strings to hang around.  This should be straightened
 257              out.  FIXME.  */
 258         }
 259     }
 260
 261   if (shandle != NULL)
 262     {
 263       if (! finish_stab (dhandle, shandle))
 264         return FALSE;
 265     }
 266
 267   return TRUE;
 268 }
 269
 270 /* Read stabs in the symbol table.  */
 271
 272 static bfd_boolean
 273 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
 274                                   void *dhandle, bfd_boolean *pfound)
 275 {
 276   void *shandle;
 277   asymbol **ps, **symend;
 278
 279   shandle = NULL;
 280   symend = syms + symcount;
 281   for (ps = syms; ps < symend; ps++)
 282     {
 283       symbol_info i;
 284
 285       bfd_get_symbol_info (abfd, *ps, &i);
 286
 287       if (i.type == '-')
 288         {
 289           const char *s;
 290           char *f;
 291
 292           if (shandle == NULL)
 293             {
 294               shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
 295               if (shandle == NULL)
 296                 return FALSE;
 297             }
 298
 299           *pfound = TRUE;
 300
 301           s = i.name;
 302           f = NULL;
 303           while (s[strlen (s) - 1] == '\\'
 304                  && ps + 1 < symend)
 305             {
 306               char *sc, *n;
 307
 308               ++ps;
 309               sc = xstrdup (s);
 310               sc[strlen (sc) - 1] = '\0';
 311               n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
 312               free (sc);
 313               if (f != NULL)
 314                 free (f);
 315               f = n;
 316               s = n;
 317             }
 318
 319           save_stab (i.stab_type, i.stab_desc, i.value, s);
 320
 321           if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
 322                             i.value, s))
 323             {
 324               stab_context ();
 325               free_saved_stabs ();
 326               return FALSE;
 327             }
 328
 329           /* Don't free f, since I think the stabs code expects
 330              strings to hang around.  This should be straightened out.
 331              FIXME.  */
 332         }
 333     }
 334
 335   free_saved_stabs ();
 336
 337   if (shandle != NULL)
 338     {
 339       if (! finish_stab (dhandle, shandle))
 340         return FALSE;
 341     }
 342
 343   return TRUE;
 344 }
 345
 346 /* Read IEEE debugging information.  */
 347
 348 static bfd_boolean
 349 read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
 350 {
 351   asection *dsec;
 352   bfd_size_type size;
 353   bfd_byte *contents;
 354
 355   /* The BFD backend puts the debugging information into a section
 356      named .debug.  */
 357
 358   dsec = bfd_get_section_by_name (abfd, ".debug");
 359   if (dsec == NULL)
 360     return TRUE;
 361
 362   size = bfd_section_size (abfd, dsec);
 363   contents = (bfd_byte *) xmalloc (size);
 364   if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
 365     return FALSE;
 366
 367   if (! parse_ieee (dhandle, abfd, contents, size))
 368     return FALSE;
 369
 370   free (contents);
 371
 372   *pfound = TRUE;
 373
 374   return TRUE;
 375 }
 376 \f
 377 /* Record stabs strings, so that we can give some context for errors.  */
 378
 379 #define SAVE_STABS_COUNT (16)
 380
 381 struct saved_stab
 382 {
 383   int type;
 384   int desc;
 385   bfd_vma value;
 386   char *string;
 387 };
 388
 389 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 390 static int saved_stabs_index;
 391
 392 /* Save a stabs string.  */
 393
 394 static void
 395 save_stab (int type, int desc, bfd_vma value, const char *string)
 396 {
 397   if (saved_stabs[saved_stabs_index].string != NULL)
 398     free (saved_stabs[saved_stabs_index].string);
 399   saved_stabs[saved_stabs_index].type = type;
 400   saved_stabs[saved_stabs_index].desc = desc;
 401   saved_stabs[saved_stabs_index].value = value;
 402   saved_stabs[saved_stabs_index].string = xstrdup (string);
 403   saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
 404 }
 405
 406 /* Provide context for an error.  */
 407
 408 static void
 409 stab_context (void)
 410 {
 411   int i;
 412
 413   fprintf (stderr, _("Last stabs entries before error:\n"));
 414   fprintf (stderr, "n_type n_desc n_value  string\n");
 415
 416   i = saved_stabs_index;
 417   do
 418     {
 419       struct saved_stab *stabp;
 420
 421       stabp = saved_stabs + i;
 422       if (stabp->string != NULL)
 423         {
 424           const char *s;
 425
 426           s = bfd_get_stab_name (stabp->type);
 427           if (s != NULL)
 428             fprintf (stderr, "%-6s", s);
 429           else if (stabp->type == 0)
 430             fprintf (stderr, "HdrSym");
 431           else
 432             fprintf (stderr, "%-6d", stabp->type);
 433           fprintf (stderr, " %-6d ", stabp->desc);
 434           fprintf_vma (stderr, stabp->value);
 435           if (stabp->type != 0)
 436             fprintf (stderr, " %s", stabp->string);
 437           fprintf (stderr, "\n");
 438         }
 439       i = (i + 1) % SAVE_STABS_COUNT;
 440     }
 441   while (i != saved_stabs_index);
 442 }
 443
 444 /* Free the saved stab strings.  */
 445
 446 static void
 447 free_saved_stabs (void)
 448 {
 449   int i;
 450
 451   for (i = 0; i < SAVE_STABS_COUNT; i++)
 452     {
 453       if (saved_stabs[i].string != NULL)
 454         {
 455           free (saved_stabs[i].string);
 456           saved_stabs[i].string = NULL;
 457         }
 458     }
 459
 460   saved_stabs_index = 0;
 461 }