bfd/bfd.c

   1 /* Generic BFD library interface and support routines.
   2    Copyright (C) 1990-1991 Free Software Foundation, Inc.
   3    Written by Cygnus Support.
   4
   5 This file is part of BFD, the Binary File Descriptor library.
   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 2 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /*
  22 SECTION
  23         <<typedef bfd>>
  24
  25         A BFD is has type <<bfd>>; objects of this type are the
  26         cornerstone of any application using <<libbfd>>. References
  27         though the BFD and to data in the BFD give the entire BFD
  28         functionality.
  29
  30         Here is the struct used to define the type <<bfd>>.  This
  31         contains the major data about the file, and contains pointers
  32         to the rest of the data.
  33
  34 CODE_FRAGMENT
  35 .
  36 .struct _bfd
  37 .{
  38 .    {* The filename the application opened the BFD with.  *}
  39 .    CONST char *filename;
  40 .
  41 .    {* A pointer to the target jump table.             *}
  42 .    struct bfd_target *xvec;
  43 .
  44 .    {* To avoid dragging too many header files into every file that
  45 .       includes `<<bfd.h>>', IOSTREAM has been declared as a "char
  46 .       *", and MTIME as a "long".  Their correct types, to which they
  47 .       are cast when used, are "FILE *" and "time_t".    The iostream
  48 .       is the result of an fopen on the filename. *}
  49 .    char *iostream;
  50 .
  51 .    {* Is the file being cached *}
  52 .
  53 .    boolean cacheable;
  54 .
  55 .    {* Marks whether there was a default target specified when the
  56 .       BFD was opened. This is used to select what matching algorithm
  57 .       to use to chose the back end. *}
  58 .
  59 .    boolean target_defaulted;
  60 .
  61 .    {* The caching routines use these to maintain a
  62 .       least-recently-used list of BFDs *}
  63 .
  64 .    struct _bfd *lru_prev, *lru_next;
  65 .
  66 .    {* When a file is closed by the caching routines, BFD retains
  67 .       state information on the file here:
  68 .     *}
  69 .
  70 .    file_ptr where;
  71 .
  72 .    {* and here:*}
  73 .
  74 .    boolean opened_once;
  75 .
  76 .    {* Set if we have a locally maintained mtime value, rather than
  77 .       getting it from the file each time: *}
  78 .
  79 .    boolean mtime_set;
  80 .
  81 .    {* File modified time, if mtime_set is true: *}
  82 .
  83 .    long mtime;
  84 .
  85 .    {* Reserved for an unimplemented file locking extension.*}
  86 .
  87 .    int ifd;
  88 .
  89 .    {* The format which belongs to the BFD.*}
  90 .
  91 .    bfd_format format;
  92 .
  93 .    {* The direction the BFD was opened with*}
  94 .
  95 .    enum bfd_direction {no_direction = 0,
  96 .                        read_direction = 1,
  97 .                        write_direction = 2,
  98 .                        both_direction = 3} direction;
  99 .
 100 .    {* Format_specific flags*}
 101 .
 102 .    flagword flags;
 103 .
 104 .    {* Currently my_archive is tested before adding origin to
 105 .       anything. I believe that this can become always an add of
 106 .       origin, with origin set to 0 for non archive files.   *}
 107 .
 108 .    file_ptr origin;
 109 .
 110 .    {* Remember when output has begun, to stop strange things
 111 .       happening. *}
 112 .    boolean output_has_begun;
 113 .
 114 .    {* Pointer to linked list of sections*}
 115 .    struct sec  *sections;
 116 .
 117 .    {* The number of sections *}
 118 .    unsigned int section_count;
 119 .
 120 .    {* Stuff only useful for object files:
 121 .       The start address. *}
 122 .    bfd_vma start_address;
 123 .
 124 .    {* Used for input and output*}
 125 .    unsigned int symcount;
 126 .
 127 .    {* Symbol table for output BFD*}
 128 .    struct symbol_cache_entry  **outsymbols;
 129 .
 130 .    {* Pointer to structure which contains architecture information*}
 131 .    struct bfd_arch_info *arch_info;
 132 .
 133 .    {* Stuff only useful for archives:*}
 134 .    PTR arelt_data;
 135 .    struct _bfd *my_archive;
 136 .    struct _bfd *next;
 137 .    struct _bfd *archive_head;
 138 .    boolean has_armap;
 139 .
 140 .    {* Used by the back end to hold private data. *}
 141 .
 142 .    union
 143 .      {
 144 .      struct aout_data_struct *aout_data;
 145 .      struct artdata *aout_ar_data;
 146 .      struct _oasys_data *oasys_obj_data;
 147 .      struct _oasys_ar_data *oasys_ar_data;
 148 .      struct coff_tdata *coff_obj_data;
 149 .      struct ecoff_tdata *ecoff_obj_data;
 150 .      struct ieee_data_struct *ieee_data;
 151 .      struct ieee_ar_data_struct *ieee_ar_data;
 152 .      struct srec_data_struct *srec_data;
 153 .      struct tekhex_data_struct *tekhex_data;
 154 .      struct elf_obj_tdata *elf_obj_data;
 155 .      struct bout_data_struct *bout_data;
 156 .      struct sun_core_struct *sun_core_data;
 157 .      struct trad_core_struct *trad_core_data;
 158 .      struct hppa_data_struct *hppa_data;
 159 .      struct hppa_core_struct *hppa_core_data;
 160 .      PTR any;
 161 .      } tdata;
 162 .
 163 .    {* Used by the application to hold private data*}
 164 .    PTR usrdata;
 165 .
 166 .    {* Where all the allocated stuff under this BFD goes *}
 167 .    struct obstack memory;
 168 .
 169 .    {* Is this really needed in addition to usrdata?  *}
 170 .    asymbol **ld_symbols;
 171 .};
 172 .
 173 */
 174
 175 #include "bfd.h"
 176 #include "sysdep.h"
 177 #include "libbfd.h"
 178
 179 #undef strerror
 180 extern char *strerror();
 181
 182
 183 CONST short _bfd_host_big_endian = 0x0100;
 184         /* Accessing the above as (*(char*)&_bfd_host_big_endian), will
 185            return 1 if the host is big-endian, 0 otherwise.
 186            (assuming that a short is two bytes long!!!  FIXME)
 187            (See HOST_IS_BIG_ENDIAN_P in bfd.h.)  */
 188 \f
 189 /** Error handling
 190     o - Most functions return nonzero on success (check doc for
 191         precise semantics); 0 or NULL on error.
 192     o - Internal errors are documented by the value of bfd_error.
 193         If that is system_call_error then check errno.
 194     o - The easiest way to report this to the user is to use bfd_perror.
 195 */
 196
 197 bfd_ec bfd_error = no_error;
 198
 199 CONST char *CONST bfd_errmsgs[] = { "No error",
 200                         "System call error",
 201                         "Invalid target",
 202                         "File in wrong format",
 203                         "Invalid operation",
 204                         "Memory exhausted",
 205                         "No symbols",
 206                         "No relocation info",
 207                         "No more archived files",
 208                         "Malformed archive",
 209                         "Symbol not found",
 210                         "File format not recognized",
 211                         "File format is ambiguous",
 212                         "Section has no contents",
 213                         "Nonrepresentable section on output",
 214                         "Symbol needs debug section which does not exist",
 215                         "Bad value",
 216                         "#<Invalid error code>"
 217                        };
 218
 219 static
 220 void
 221 DEFUN(bfd_nonrepresentable_section,(abfd, name),
 222          CONST  bfd * CONST abfd AND
 223          CONST  char * CONST name)
 224 {
 225   printf("bfd error writing file %s, format %s can't represent section %s\n",
 226          abfd->filename,
 227          abfd->xvec->name,
 228          name);
 229   exit(1);
 230 }
 231
 232 /*ARGSUSED*/
 233 static
 234 void
 235 DEFUN(bfd_undefined_symbol,(relent, seclet),
 236       CONST  arelent *relent AND
 237       CONST  struct bfd_seclet *seclet)
 238 {
 239   asymbol *symbol = *(relent->sym_ptr_ptr);
 240   printf("bfd error relocating, symbol %s is undefined\n",
 241          symbol->name);
 242   exit(1);
 243 }
 244 /*ARGSUSED*/
 245 static
 246 void
 247 DEFUN(bfd_reloc_value_truncated,(relent, seclet),
 248          CONST  arelent *relent AND
 249       struct bfd_seclet *seclet)
 250 {
 251   printf("bfd error relocating, value truncated\n");
 252   exit(1);
 253 }
 254 /*ARGSUSED*/
 255 static
 256 void
 257 DEFUN(bfd_reloc_is_dangerous,(relent, seclet),
 258       CONST  arelent *relent AND
 259      CONST  struct bfd_seclet *seclet)
 260 {
 261   printf("bfd error relocating, dangerous\n");
 262   exit(1);
 263 }
 264
 265 bfd_error_vector_type bfd_error_vector =
 266   {
 267   bfd_nonrepresentable_section ,
 268   bfd_undefined_symbol,
 269   bfd_reloc_value_truncated,
 270   bfd_reloc_is_dangerous,
 271   };
 272
 273
 274 CONST char *
 275 bfd_errmsg (error_tag)
 276      bfd_ec error_tag;
 277 {
 278 #ifndef errno
 279   extern int errno;
 280 #endif
 281   if (error_tag == system_call_error)
 282     return strerror (errno);
 283
 284   if ((((int)error_tag <(int) no_error) ||
 285        ((int)error_tag > (int)invalid_error_code)))
 286     error_tag = invalid_error_code;/* sanity check */
 287
 288   return bfd_errmsgs [(int)error_tag];
 289 }
 290
 291
 292 void bfd_default_error_trap(error_tag)
 293 bfd_ec error_tag;
 294 {
 295   printf("bfd assert fail (%s)\n", bfd_errmsg(error_tag));
 296 }
 297
 298 void (*bfd_error_trap)() = bfd_default_error_trap;
 299 void (*bfd_error_nonrepresentabltrap)() = bfd_default_error_trap;
 300
 301 void
 302 DEFUN(bfd_perror,(message),
 303       CONST char *message)
 304 {
 305   if (bfd_error == system_call_error)
 306     perror((char *)message);            /* must be system error then... */
 307   else {
 308     if (message == NULL || *message == '\0')
 309       fprintf (stderr, "%s\n", bfd_errmsg (bfd_error));
 310     else
 311       fprintf (stderr, "%s: %s\n", message, bfd_errmsg (bfd_error));
 312   }
 313 }
 314
 315  \f
 316 /** Symbols */
 317
 318
 319 /*
 320 FUNCTION
 321         bfd_get_reloc_upper_bound
 322
 323 SYNOPSIS
 324         unsigned int bfd_get_reloc_upper_bound(bfd *abfd, asection *sect);
 325
 326 DESCRIPTION
 327         This function return the number of bytes required to store the
 328         relocation information associated with section <<sect>>
 329         attached to bfd <<abfd>>
 330
 331 */
 332
 333
 334 unsigned int
 335 DEFUN(bfd_get_reloc_upper_bound,(abfd, asect),
 336      bfd *abfd AND
 337      sec_ptr asect)
 338 {
 339   if (abfd->format != bfd_object) {
 340     bfd_error = invalid_operation;
 341     return 0;
 342   }
 343
 344   return BFD_SEND (abfd, _get_reloc_upper_bound, (abfd, asect));
 345 }
 346
 347 /*
 348 FUNCTION
 349         bfd_canonicalize_reloc
 350
 351 SYNOPSIS
 352         unsigned int bfd_canonicalize_reloc
 353                 (bfd *abfd,
 354                 asection *sec,
 355                 arelent **loc,
 356                 asymbol **syms);
 357
 358 DESCRIPTION
 359         This function calls the back end associated with the open
 360         <<abfd>> and translates the external form of the relocation
 361         information attached to <<sec>> into the internal canonical
 362         form.  The table is placed into memory at <<loc>>, which has
 363         been preallocated, usually by a call to
 364         <<bfd_get_reloc_upper_bound>>.
 365
 366         The <<syms>> table is also needed for horrible internal magic
 367         reasons.
 368
 369
 370 */
 371 unsigned int
 372 DEFUN(bfd_canonicalize_reloc,(abfd, asect, location, symbols),
 373      bfd *abfd AND
 374      sec_ptr asect AND
 375      arelent **location AND
 376      asymbol **symbols)
 377 {
 378     if (abfd->format != bfd_object) {
 379             bfd_error = invalid_operation;
 380             return 0;
 381         }
 382     return BFD_SEND (abfd, _bfd_canonicalize_reloc,
 383                      (abfd, asect, location, symbols));
 384   }
 385
 386
 387 /*
 388 FUNCTION
 389         bfd_set_file_flags
 390
 391 SYNOPSIS
 392         boolean bfd_set_file_flags(bfd *abfd, flagword flags);
 393
 394 DESCRIPTION
 395         This function attempts to set the flag word in the referenced
 396         BFD structure to the value supplied.
 397
 398         Possible errors are:
 399         o wrong_format - The target bfd was not of object format.
 400         o invalid_operation - The target bfd was open for reading.
 401         o invalid_operation -
 402         The flag word contained a bit which was not applicable to the
 403         type of file. eg, an attempt was made to set the D_PAGED bit
 404         on a bfd format which does not support demand paging
 405
 406 */
 407
 408 boolean
 409 bfd_set_file_flags (abfd, flags)
 410      bfd *abfd;
 411      flagword flags;
 412 {
 413   if (abfd->format != bfd_object) {
 414     bfd_error = wrong_format;
 415     return false;
 416   }
 417
 418   if (bfd_read_p (abfd)) {
 419     bfd_error = invalid_operation;
 420     return false;
 421   }
 422
 423   bfd_get_file_flags (abfd) = flags;
 424   if ((flags & bfd_applicable_file_flags (abfd)) != flags) {
 425     bfd_error = invalid_operation;
 426     return false;
 427   }
 428
 429 return true;
 430 }
 431
 432 /*
 433 FUNCTION
 434         bfd_set_reloc
 435
 436 SYNOPSIS
 437         void bfd_set_reloc
 438           (bfd *abfd, asection *sec, arelent **rel, unsigned int count)
 439
 440 DESCRIPTION
 441         This function sets the relocation pointer and count within a
 442         section to the supplied values.
 443
 444 */
 445 /*ARGSUSED*/
 446 void
 447 bfd_set_reloc (ignore_abfd, asect, location, count)
 448      bfd *ignore_abfd;
 449      sec_ptr asect;
 450      arelent **location;
 451      unsigned int count;
 452 {
 453   asect->orelocation  = location;
 454   asect->reloc_count = count;
 455 }
 456
 457 void
 458 bfd_assert(file, line)
 459 char *file;
 460 int line;
 461 {
 462   printf("bfd assertion fail %s:%d\n",file,line);
 463 }
 464
 465
 466 /*
 467 FUNCTION
 468         bfd_set_start_address
 469
 470 DESCRIPTION
 471         Marks the entry point of an output BFD.
 472
 473 RETURNS
 474         Returns <<true>> on success, <<false>> otherwise.
 475
 476 SYNOPSIS
 477         boolean bfd_set_start_address(bfd *, bfd_vma);
 478 */
 479
 480 boolean
 481 bfd_set_start_address(abfd, vma)
 482 bfd *abfd;
 483 bfd_vma vma;
 484 {
 485   abfd->start_address = vma;
 486   return true;
 487 }
 488
 489
 490 /*
 491 FUNCTION
 492         The bfd_get_mtime function
 493
 494 SYNOPSIS
 495         long bfd_get_mtime(bfd *);
 496
 497 DESCRIPTION
 498         Return file modification time (as read from file system, or
 499         from archive header for archive members).
 500
 501 */
 502
 503 long
 504 bfd_get_mtime (abfd)
 505      bfd *abfd;
 506 {
 507   FILE *fp;
 508   struct stat buf;
 509
 510   if (abfd->mtime_set)
 511     return abfd->mtime;
 512
 513   fp = bfd_cache_lookup (abfd);
 514   if (0 != fstat (fileno (fp), &buf))
 515     return 0;
 516
 517   abfd->mtime = buf.st_mtime;           /* Save value in case anyone wants it */
 518   return buf.st_mtime;
 519 }
 520
 521 /*
 522 FUNCTION
 523         The bfd_get_size function
 524
 525 SYNOPSIS
 526         long bfd_get_size(bfd *);
 527
 528 DESCRIPTION
 529         Return file size (as read from file system) for the file
 530         associated with a bfd.
 531
 532         Note that the initial motivation for, and use of, this routine is not
 533         so we can get the exact size of the object the bfd applies to, since
 534         that might not be generally possible (archive members for example?).
 535         Although it would be ideal if someone could eventually modify
 536         it so that such results were guaranteed.
 537
 538         Instead, we want to ask questions like "is this NNN byte sized
 539         object I'm about to try read from file offset YYY reasonable?"
 540         As as example of where we might want to do this, some object formats
 541         use string tables for which the first sizeof(long) bytes of the table
 542         contain the size of the table itself, including the size bytes.
 543         If an application tries to read what it thinks is one of these
 544         string tables, without some way to validate the size, and for
 545         some reason the size is wrong (byte swapping error, wrong location
 546         for the string table, etc), the only clue is likely to be a read
 547         error when it tries to read the table, or a "virtual memory
 548         exhausted" error when it tries to allocated 15 bazillon bytes
 549         of space for the 15 bazillon byte table it is about to read.
 550         This function at least allows us to answer the quesion, "is the
 551         size reasonable?".
 552 */
 553
 554 long
 555 bfd_get_size (abfd)
 556      bfd *abfd;
 557 {
 558   FILE *fp;
 559   struct stat buf;
 560
 561   fp = bfd_cache_lookup (abfd);
 562   if (0 != fstat (fileno (fp), &buf))
 563     return 0;
 564
 565   return buf.st_size;
 566 }
 567
 568 /*
 569 FUNCTION
 570         stuff
 571
 572 DESCRIPTION
 573         stuff which should be documented
 574
 575 .#define bfd_sizeof_headers(abfd, reloc) \
 576 .     BFD_SEND (abfd, _bfd_sizeof_headers, (abfd, reloc))
 577 .
 578 .#define bfd_find_nearest_line(abfd, sec, syms, off, file, func, line) \
 579 .     BFD_SEND (abfd, _bfd_find_nearest_line,  (abfd, sec, syms, off, file, func, line))
 580 .
 581 .       {* Do these three do anything useful at all, for any back end?  *}
 582 .#define bfd_debug_info_start(abfd) \
 583 .        BFD_SEND (abfd, _bfd_debug_info_start, (abfd))
 584 .
 585 .#define bfd_debug_info_end(abfd) \
 586 .        BFD_SEND (abfd, _bfd_debug_info_end, (abfd))
 587 .
 588 .#define bfd_debug_info_accumulate(abfd, section) \
 589 .        BFD_SEND (abfd, _bfd_debug_info_accumulate, (abfd, section))
 590 .
 591 .
 592 .#define bfd_stat_arch_elt(abfd, stat) \
 593 .        BFD_SEND (abfd, _bfd_stat_arch_elt,(abfd, stat))
 594 .
 595 .#define bfd_set_arch_mach(abfd, arch, mach)\
 596 .        BFD_SEND ( abfd, _bfd_set_arch_mach, (abfd, arch, mach))
 597 .
 598 .#define bfd_get_relocated_section_contents(abfd, seclet, data) \
 599 .       BFD_SEND (abfd, _bfd_get_relocated_section_contents, (abfd, seclet, data))
 600 .
 601 .#define bfd_relax_section(abfd, section, symbols) \
 602 .       BFD_SEND (abfd, _bfd_relax_section, (abfd, section, symbols))
 603
 604 */
 605
 606
 607
 608
 609
 610