bfd/bfd.c

   1 /* Generic BFD library interface and support routines.
   2    Copyright (C) 1990, 1991, 1992, 1993 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 nlm_obj_tdata *nlm_obj_data;
 156 .      struct bout_data_struct *bout_data;
 157 .      struct sun_core_struct *sun_core_data;
 158 .      struct trad_core_struct *trad_core_data;
 159 .      struct hppa_data_struct *hppa_data;
 160 .      struct hpux_core_struct *hpux_core_data;
 161 .      struct sgi_core_struct *sgi_core_data;
 162 .      PTR any;
 163 .      } tdata;
 164 .
 165 .    {* Used by the application to hold private data*}
 166 .    PTR usrdata;
 167 .
 168 .    {* Where all the allocated stuff under this BFD goes *}
 169 .    struct obstack memory;
 170 .
 171 .    {* Is this really needed in addition to usrdata?  *}
 172 .    asymbol **ld_symbols;
 173 .};
 174 .
 175 */
 176
 177 #include "bfd.h"
 178 #include "sysdep.h"
 179 #include "libbfd.h"
 180 #include "coff/internal.h"
 181 #include "coff/sym.h"
 182 #include "libcoff.h"
 183 #include "libecoff.h"
 184
 185 #undef strerror
 186 extern char *strerror();
 187
 188
 189 CONST short _bfd_host_big_endian = 0x0100;
 190         /* Accessing the above as (*(char*)&_bfd_host_big_endian), will
 191            return 1 if the host is big-endian, 0 otherwise.
 192            (assuming that a short is two bytes long!!!  FIXME)
 193            (See HOST_IS_BIG_ENDIAN_P in bfd.h.)  */
 194 \f
 195 /** Error handling
 196     o - Most functions return nonzero on success (check doc for
 197         precise semantics); 0 or NULL on error.
 198     o - Internal errors are documented by the value of bfd_error.
 199         If that is system_call_error then check errno.
 200     o - The easiest way to report this to the user is to use bfd_perror.
 201 */
 202
 203 bfd_ec bfd_error = no_error;
 204
 205 CONST char *CONST bfd_errmsgs[] = {
 206                         "No error",
 207                         "System call error",
 208                         "Invalid target",
 209                         "File in wrong format",
 210                         "Invalid operation",
 211                         "Memory exhausted",
 212                         "No symbols",
 213                         "No relocation info",
 214                         "No more archived files",
 215                         "Malformed archive",
 216                         "Symbol not found",
 217                         "File format not recognized",
 218                         "File format is ambiguous",
 219                         "Section has no contents",
 220                         "Nonrepresentable section on output",
 221                         "Symbol needs debug section which does not exist",
 222                         "Bad value",
 223                         "File truncated",
 224                         "#<Invalid error code>"
 225                        };
 226
 227 static
 228 void
 229 DEFUN(bfd_nonrepresentable_section,(abfd, name),
 230          CONST  bfd * CONST abfd AND
 231          CONST  char * CONST name)
 232 {
 233   fprintf(stderr,
 234           "bfd error writing file %s, format %s can't represent section %s\n",
 235           abfd->filename,
 236           abfd->xvec->name,
 237           name);
 238   exit(1);
 239 }
 240
 241 /*ARGSUSED*/
 242 static
 243 void
 244 DEFUN(bfd_undefined_symbol,(relent, seclet),
 245       CONST  arelent *relent AND
 246       CONST  struct bfd_seclet *seclet)
 247 {
 248   asymbol *symbol = *(relent->sym_ptr_ptr);
 249   fprintf(stderr, "bfd error relocating, symbol %s is undefined\n",
 250           symbol->name);
 251   exit(1);
 252 }
 253 /*ARGSUSED*/
 254 static
 255 void
 256 DEFUN(bfd_reloc_value_truncated,(relent, seclet),
 257          CONST  arelent *relent AND
 258       struct bfd_seclet *seclet)
 259 {
 260   fprintf(stderr, "bfd error relocating, value truncated\n");
 261   exit(1);
 262 }
 263 /*ARGSUSED*/
 264 static
 265 void
 266 DEFUN(bfd_reloc_is_dangerous,(relent, seclet),
 267       CONST  arelent *relent AND
 268      CONST  struct bfd_seclet *seclet)
 269 {
 270   fprintf(stderr, "bfd error relocating, dangerous\n");
 271   exit(1);
 272 }
 273
 274 bfd_error_vector_type bfd_error_vector =
 275   {
 276   bfd_nonrepresentable_section ,
 277   bfd_undefined_symbol,
 278   bfd_reloc_value_truncated,
 279   bfd_reloc_is_dangerous,
 280   };
 281
 282
 283 CONST char *
 284 bfd_errmsg (error_tag)
 285      bfd_ec error_tag;
 286 {
 287 #ifndef errno
 288   extern int errno;
 289 #endif
 290   if (error_tag == system_call_error)
 291     return strerror (errno);
 292
 293   if ((((int)error_tag <(int) no_error) ||
 294        ((int)error_tag > (int)invalid_error_code)))
 295     error_tag = invalid_error_code;/* sanity check */
 296
 297   return bfd_errmsgs [(int)error_tag];
 298 }
 299
 300 void
 301 DEFUN (bfd_default_error_trap, (error_tag),
 302        bfd_ec error_tag)
 303 {
 304   fprintf(stderr, "bfd assert fail (%s)\n", bfd_errmsg(error_tag));
 305 }
 306
 307 void (*bfd_error_trap) PARAMS ((bfd_ec)) = bfd_default_error_trap;
 308 void (*bfd_error_nonrepresentabltrap) PARAMS ((bfd_ec)) = bfd_default_error_trap;
 309
 310 void
 311 DEFUN(bfd_perror,(message),
 312       CONST char *message)
 313 {
 314   if (bfd_error == system_call_error)
 315     perror((char *)message);            /* must be system error then... */
 316   else {
 317     if (message == NULL || *message == '\0')
 318       fprintf (stderr, "%s\n", bfd_errmsg (bfd_error));
 319     else
 320       fprintf (stderr, "%s: %s\n", message, bfd_errmsg (bfd_error));
 321   }
 322 }
 323
 324  \f
 325 /** Symbols */
 326
 327
 328 /*
 329 FUNCTION
 330         bfd_get_reloc_upper_bound
 331
 332 SYNOPSIS
 333         unsigned int bfd_get_reloc_upper_bound(bfd *abfd, asection *sect);
 334
 335 DESCRIPTION
 336         This function return the number of bytes required to store the
 337         relocation information associated with section <<sect>>
 338         attached to bfd <<abfd>>
 339
 340 */
 341
 342
 343 unsigned int
 344 DEFUN(bfd_get_reloc_upper_bound,(abfd, asect),
 345      bfd *abfd AND
 346      sec_ptr asect)
 347 {
 348   if (abfd->format != bfd_object) {
 349     bfd_error = invalid_operation;
 350     return 0;
 351   }
 352
 353   return BFD_SEND (abfd, _get_reloc_upper_bound, (abfd, asect));
 354 }
 355
 356 /*
 357 FUNCTION
 358         bfd_canonicalize_reloc
 359
 360 SYNOPSIS
 361         unsigned int bfd_canonicalize_reloc
 362                 (bfd *abfd,
 363                 asection *sec,
 364                 arelent **loc,
 365                 asymbol **syms);
 366
 367 DESCRIPTION
 368         This function calls the back end associated with the open
 369         <<abfd>> and translates the external form of the relocation
 370         information attached to <<sec>> into the internal canonical
 371         form.  The table is placed into memory at <<loc>>, which has
 372         been preallocated, usually by a call to
 373         <<bfd_get_reloc_upper_bound>>.
 374
 375         The <<syms>> table is also needed for horrible internal magic
 376         reasons.
 377
 378
 379 */
 380 unsigned int
 381 DEFUN(bfd_canonicalize_reloc,(abfd, asect, location, symbols),
 382      bfd *abfd AND
 383      sec_ptr asect AND
 384      arelent **location AND
 385      asymbol **symbols)
 386 {
 387     if (abfd->format != bfd_object) {
 388             bfd_error = invalid_operation;
 389             return 0;
 390         }
 391     return BFD_SEND (abfd, _bfd_canonicalize_reloc,
 392                      (abfd, asect, location, symbols));
 393   }
 394
 395
 396 /*
 397 FUNCTION
 398         bfd_set_file_flags
 399
 400 SYNOPSIS
 401         boolean bfd_set_file_flags(bfd *abfd, flagword flags);
 402
 403 DESCRIPTION
 404         This function attempts to set the flag word in the referenced
 405         BFD structure to the value supplied.
 406
 407         Possible errors are:
 408         o wrong_format - The target bfd was not of object format.
 409         o invalid_operation - The target bfd was open for reading.
 410         o invalid_operation -
 411         The flag word contained a bit which was not applicable to the
 412         type of file. eg, an attempt was made to set the D_PAGED bit
 413         on a bfd format which does not support demand paging
 414
 415 */
 416
 417 boolean
 418 bfd_set_file_flags (abfd, flags)
 419      bfd *abfd;
 420      flagword flags;
 421 {
 422   if (abfd->format != bfd_object) {
 423     bfd_error = wrong_format;
 424     return false;
 425   }
 426
 427   if (bfd_read_p (abfd)) {
 428     bfd_error = invalid_operation;
 429     return false;
 430   }
 431
 432   bfd_get_file_flags (abfd) = flags;
 433   if ((flags & bfd_applicable_file_flags (abfd)) != flags) {
 434     bfd_error = invalid_operation;
 435     return false;
 436   }
 437
 438 return true;
 439 }
 440
 441 /*
 442 FUNCTION
 443         bfd_set_reloc
 444
 445 SYNOPSIS
 446         void bfd_set_reloc
 447           (bfd *abfd, asection *sec, arelent **rel, unsigned int count)
 448
 449 DESCRIPTION
 450         This function sets the relocation pointer and count within a
 451         section to the supplied values.
 452
 453 */
 454 /*ARGSUSED*/
 455 void
 456 bfd_set_reloc (ignore_abfd, asect, location, count)
 457      bfd *ignore_abfd;
 458      sec_ptr asect;
 459      arelent **location;
 460      unsigned int count;
 461 {
 462   asect->orelocation  = location;
 463   asect->reloc_count = count;
 464 }
 465
 466 void
 467 bfd_assert(file, line)
 468 char *file;
 469 int line;
 470 {
 471   fprintf(stderr, "bfd assertion fail %s:%d\n",file,line);
 472 }
 473
 474
 475 /*
 476 FUNCTION
 477         bfd_set_start_address
 478
 479 DESCRIPTION
 480         Marks the entry point of an output BFD.
 481
 482 RETURNS
 483         Returns <<true>> on success, <<false>> otherwise.
 484
 485 SYNOPSIS
 486         boolean bfd_set_start_address(bfd *, bfd_vma);
 487 */
 488
 489 boolean
 490 bfd_set_start_address(abfd, vma)
 491 bfd *abfd;
 492 bfd_vma vma;
 493 {
 494   abfd->start_address = vma;
 495   return true;
 496 }
 497
 498
 499 /*
 500 FUNCTION
 501         The bfd_get_mtime function
 502
 503 SYNOPSIS
 504         long bfd_get_mtime(bfd *);
 505
 506 DESCRIPTION
 507         Return file modification time (as read from file system, or
 508         from archive header for archive members).
 509
 510 */
 511
 512 long
 513 bfd_get_mtime (abfd)
 514      bfd *abfd;
 515 {
 516   FILE *fp;
 517   struct stat buf;
 518
 519   if (abfd->mtime_set)
 520     return abfd->mtime;
 521
 522   fp = bfd_cache_lookup (abfd);
 523   if (0 != fstat (fileno (fp), &buf))
 524     return 0;
 525
 526   abfd->mtime = buf.st_mtime;           /* Save value in case anyone wants it */
 527   return buf.st_mtime;
 528 }
 529
 530 /*
 531 FUNCTION
 532         The bfd_get_size function
 533
 534 SYNOPSIS
 535         long bfd_get_size(bfd *);
 536
 537 DESCRIPTION
 538         Return file size (as read from file system) for the file
 539         associated with a bfd.
 540
 541         Note that the initial motivation for, and use of, this routine is not
 542         so we can get the exact size of the object the bfd applies to, since
 543         that might not be generally possible (archive members for example?).
 544         Although it would be ideal if someone could eventually modify
 545         it so that such results were guaranteed.
 546
 547         Instead, we want to ask questions like "is this NNN byte sized
 548         object I'm about to try read from file offset YYY reasonable?"
 549         As as example of where we might want to do this, some object formats
 550         use string tables for which the first sizeof(long) bytes of the table
 551         contain the size of the table itself, including the size bytes.
 552         If an application tries to read what it thinks is one of these
 553         string tables, without some way to validate the size, and for
 554         some reason the size is wrong (byte swapping error, wrong location
 555         for the string table, etc), the only clue is likely to be a read
 556         error when it tries to read the table, or a "virtual memory
 557         exhausted" error when it tries to allocated 15 bazillon bytes
 558         of space for the 15 bazillon byte table it is about to read.
 559         This function at least allows us to answer the quesion, "is the
 560         size reasonable?".
 561 */
 562
 563 long
 564 bfd_get_size (abfd)
 565      bfd *abfd;
 566 {
 567   FILE *fp;
 568   struct stat buf;
 569
 570   fp = bfd_cache_lookup (abfd);
 571   if (0 != fstat (fileno (fp), &buf))
 572     return 0;
 573
 574   return buf.st_size;
 575 }
 576
 577 /*
 578 FUNCTION
 579         The bfd_get_gp_size function
 580
 581 SYNOPSIS
 582         int bfd_get_gp_size(bfd *);
 583
 584 DESCRIPTION
 585         Get the maximum size of objects to be optimized using the GP
 586         register under MIPS ECOFF.  This is typically set by the -G
 587         argument to the compiler, assembler or linker.
 588 */
 589
 590 int
 591 bfd_get_gp_size (abfd)
 592      bfd *abfd;
 593 {
 594   if (abfd->xvec->flavour == bfd_target_ecoff_flavour)
 595     return ecoff_data (abfd)->gp_size;
 596   return 0;
 597 }
 598
 599 /*
 600 FUNCTION
 601         The bfd_set_gp_size function
 602
 603 SYNOPSIS
 604         void bfd_set_gp_size(bfd *, int);
 605
 606 DESCRIPTION
 607         Set the maximum size of objects to be optimized using the GP
 608         register under MIPS ECOFF.  This is typically set by the -G
 609         argument to the compiler, assembler or linker.
 610 */
 611
 612 void
 613 bfd_set_gp_size (abfd, i)
 614      bfd *abfd;
 615      int i;
 616 {
 617   if (abfd->xvec->flavour == bfd_target_ecoff_flavour)
 618     ecoff_data (abfd)->gp_size = i;
 619 }
 620
 621 /*
 622 FUNCTION
 623         stuff
 624
 625 DESCRIPTION
 626         stuff which should be documented
 627
 628 .#define bfd_sizeof_headers(abfd, reloc) \
 629 .     BFD_SEND (abfd, _bfd_sizeof_headers, (abfd, reloc))
 630 .
 631 .#define bfd_find_nearest_line(abfd, sec, syms, off, file, func, line) \
 632 .     BFD_SEND (abfd, _bfd_find_nearest_line,  (abfd, sec, syms, off, file, func, line))
 633 .
 634 .       {* Do these three do anything useful at all, for any back end?  *}
 635 .#define bfd_debug_info_start(abfd) \
 636 .        BFD_SEND (abfd, _bfd_debug_info_start, (abfd))
 637 .
 638 .#define bfd_debug_info_end(abfd) \
 639 .        BFD_SEND (abfd, _bfd_debug_info_end, (abfd))
 640 .
 641 .#define bfd_debug_info_accumulate(abfd, section) \
 642 .        BFD_SEND (abfd, _bfd_debug_info_accumulate, (abfd, section))
 643 .
 644 .
 645 .#define bfd_stat_arch_elt(abfd, stat) \
 646 .        BFD_SEND (abfd, _bfd_stat_arch_elt,(abfd, stat))
 647 .
 648 .#define bfd_set_arch_mach(abfd, arch, mach)\
 649 .        BFD_SEND ( abfd, _bfd_set_arch_mach, (abfd, arch, mach))
 650 .
 651 .#define bfd_get_relocated_section_contents(abfd, seclet, data, relocateable) \
 652 .       BFD_SEND (abfd, _bfd_get_relocated_section_contents, (abfd, seclet, data, relocateable))
 653 .
 654 .#define bfd_relax_section(abfd, section, symbols) \
 655 .       BFD_SEND (abfd, _bfd_relax_section, (abfd, section, symbols))
 656 .
 657 .#define bfd_seclet_link(abfd, data, relocateable) \
 658 .       BFD_SEND (abfd, _bfd_seclet_link, (abfd, data, relocateable))
 659
 660 */