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 has type <<bfd>>; objects of this type are the
  26         cornerstone of any application using BFD. Using BFD
  27         consists of making references though the BFD and to data in the BFD.
  28
  29         Here is the structure that defines the type <<bfd>>.  It
  30         contains the major data about the file and pointers
  31         to the rest of the data.
  32
  33 CODE_FRAGMENT
  34 .
  35 .struct _bfd
  36 .{
  37 .    {* The filename the application opened the BFD with.  *}
  38 .    CONST char *filename;
  39 .
  40 .    {* A pointer to the target jump table.             *}
  41 .    struct bfd_target *xvec;
  42 .
  43 .    {* To avoid dragging too many header files into every file that
  44 .       includes `<<bfd.h>>', IOSTREAM has been declared as a "char
  45 .       *", and MTIME as a "long".  Their correct types, to which they
  46 .       are cast when used, are "FILE *" and "time_t".    The iostream
  47 .       is the result of an fopen on the filename. *}
  48 .    char *iostream;
  49 .
  50 .    {* Is the file descriptor being cached?  That is, can it be closed as
  51 .       needed, and re-opened when accessed later?  *}
  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 which matching algorithm
  57 .       to use to choose 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 .    file_ptr where;
  70 .
  71 .    {* and here: (``once'' means at least once) *}
  72 .
  73 .    boolean opened_once;
  74 .
  75 .    {* Set if we have a locally maintained mtime value, rather than
  76 .       getting it from the file each time: *}
  77 .
  78 .    boolean mtime_set;
  79 .
  80 .    {* File modified time, if mtime_set is true: *}
  81 .
  82 .    long mtime;
  83 .
  84 .    {* Reserved for an unimplemented file locking extension.*}
  85 .
  86 .    int ifd;
  87 .
  88 .    {* The format which belongs to the BFD. (object, core, etc.) *}
  89 .
  90 .    bfd_format format;
  91 .
  92 .    {* The direction the BFD was opened with*}
  93 .
  94 .    enum bfd_direction {no_direction = 0,
  95 .                        read_direction = 1,
  96 .                        write_direction = 2,
  97 .                        both_direction = 3} direction;
  98 .
  99 .    {* Format_specific flags*}
 100 .
 101 .    flagword flags;
 102 .
 103 .    {* Currently my_archive is tested before adding origin to
 104 .       anything. I believe that this can become always an add of
 105 .       origin, with origin set to 0 for non archive files.   *}
 106 .
 107 .    file_ptr origin;
 108 .
 109 .    {* Remember when output has begun, to stop strange things
 110 .       from happening. *}
 111 .    boolean output_has_begun;
 112 .
 113 .    {* Pointer to linked list of sections*}
 114 .    struct sec  *sections;
 115 .
 116 .    {* The number of sections *}
 117 .    unsigned int section_count;
 118 .
 119 .    {* Stuff only useful for object files:
 120 .       The start address. *}
 121 .    bfd_vma start_address;
 122 .
 123 .    {* Used for input and output*}
 124 .    unsigned int symcount;
 125 .
 126 .    {* Symbol table for output BFD (with symcount entries) *}
 127 .    struct symbol_cache_entry  **outsymbols;
 128 .
 129 .    {* Pointer to structure which contains architecture information*}
 130 .    struct bfd_arch_info *arch_info;
 131 .
 132 .    {* Stuff only useful for archives:*}
 133 .    PTR arelt_data;
 134 .    struct _bfd *my_archive;     {* The containing archive BFD.  *}
 135 .    struct _bfd *next;           {* The next BFD in the archive.  *}
 136 .    struct _bfd *archive_head;   {* The first BFD in the archive.  *}
 137 .    boolean has_armap;
 138 .
 139 .    {* A chain of BFD structures involved in a link.  *}
 140 .    struct _bfd *link_next;
 141 .
 142 .    {* A field used by _bfd_generic_link_add_archive_symbols.  This will
 143 .       be used only for archive elements.  *}
 144 .    int archive_pass;
 145 .
 146 .    {* Used by the back end to hold private data. *}
 147 .
 148 .    union
 149 .      {
 150 .      struct aout_data_struct *aout_data;
 151 .      struct artdata *aout_ar_data;
 152 .      struct _oasys_data *oasys_obj_data;
 153 .      struct _oasys_ar_data *oasys_ar_data;
 154 .      struct coff_tdata *coff_obj_data;
 155 .      struct ecoff_tdata *ecoff_obj_data;
 156 .      struct ieee_data_struct *ieee_data;
 157 .      struct ieee_ar_data_struct *ieee_ar_data;
 158 .      struct srec_data_struct *srec_data;
 159 .      struct tekhex_data_struct *tekhex_data;
 160 .      struct elf_obj_tdata *elf_obj_data;
 161 .      struct nlm_obj_tdata *nlm_obj_data;
 162 .      struct bout_data_struct *bout_data;
 163 .      struct sun_core_struct *sun_core_data;
 164 .      struct trad_core_struct *trad_core_data;
 165 .      struct som_data_struct *som_data;
 166 .      struct hpux_core_struct *hpux_core_data;
 167 .      struct hppabsd_core_struct *hppabsd_core_data;
 168 .      struct sgi_core_struct *sgi_core_data;
 169 .      struct lynx_core_struct *lynx_core_data;
 170 .      struct osf_core_struct *osf_core_data;
 171 .      PTR any;
 172 .      } tdata;
 173 .
 174 .    {* Used by the application to hold private data*}
 175 .    PTR usrdata;
 176 .
 177 .    {* Where all the allocated stuff under this BFD goes *}
 178 .    struct obstack memory;
 179 .};
 180 .
 181 */
 182
 183 #include "bfd.h"
 184 #include "sysdep.h"
 185 #include "bfdlink.h"
 186 #include "libbfd.h"
 187 #include "coff/internal.h"
 188 #include "coff/sym.h"
 189 #include "libcoff.h"
 190 #include "libecoff.h"
 191 #undef obj_symbols
 192 #include "libelf.h"
 193
 194 #undef strerror
 195 extern char *strerror();
 196
 197 /** Error handling
 198     o - Most functions return nonzero on success (check doc for
 199         precise semantics); 0 or NULL on error.
 200     o - Internal errors are documented by the value of bfd_error.
 201         If that is system_call_error then check errno.
 202     o - The easiest way to report this to the user is to use bfd_perror.
 203 */
 204
 205 bfd_ec bfd_error = no_error;
 206
 207 CONST char *CONST bfd_errmsgs[] = {
 208                         "No error",
 209                         "System call error",
 210                         "Invalid bfd target",
 211                         "File in wrong format",
 212                         "Invalid operation",
 213                         "Memory exhausted",
 214                         "No symbols",
 215                         "No more archived files",
 216                         "Malformed archive",
 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 CONST char *
 228 bfd_errmsg (error_tag)
 229      bfd_ec error_tag;
 230 {
 231 #ifndef errno
 232   extern int errno;
 233 #endif
 234   if (error_tag == system_call_error)
 235     return strerror (errno);
 236
 237   if ((((int)error_tag <(int) no_error) ||
 238        ((int)error_tag > (int)invalid_error_code)))
 239     error_tag = invalid_error_code;/* sanity check */
 240
 241   return bfd_errmsgs [(int)error_tag];
 242 }
 243
 244 void
 245 DEFUN(bfd_perror,(message),
 246       CONST char *message)
 247 {
 248   if (bfd_error == system_call_error)
 249     perror((char *)message);            /* must be system error then... */
 250   else {
 251     if (message == NULL || *message == '\0')
 252       fprintf (stderr, "%s\n", bfd_errmsg (bfd_error));
 253     else
 254       fprintf (stderr, "%s: %s\n", message, bfd_errmsg (bfd_error));
 255   }
 256 }
 257
 258  \f
 259 /** Symbols */
 260
 261
 262 /*
 263 FUNCTION
 264         bfd_get_reloc_upper_bound
 265
 266 SYNOPSIS
 267         unsigned int bfd_get_reloc_upper_bound(bfd *abfd, asection *sect);
 268
 269 DESCRIPTION
 270         Return the number of bytes required to store the
 271         relocation information associated with section @var{sect}
 272         attached to bfd @var{abfd}.
 273
 274 */
 275
 276
 277 unsigned int
 278 DEFUN(bfd_get_reloc_upper_bound,(abfd, asect),
 279      bfd *abfd AND
 280      sec_ptr asect)
 281 {
 282   if (abfd->format != bfd_object) {
 283     bfd_error = invalid_operation;
 284     return 0;
 285   }
 286
 287   return BFD_SEND (abfd, _get_reloc_upper_bound, (abfd, asect));
 288 }
 289
 290 /*
 291 FUNCTION
 292         bfd_canonicalize_reloc
 293
 294 SYNOPSIS
 295         unsigned int bfd_canonicalize_reloc
 296                 (bfd *abfd,
 297                 asection *sec,
 298                 arelent **loc,
 299                 asymbol **syms);
 300
 301 DESCRIPTION
 302         Call the back end associated with the open BFD
 303         @var{abfd} and translate the external form of the relocation
 304         information attached to @var{sec} into the internal canonical
 305         form.  Place the table into memory at @var{loc}, which has
 306         been preallocated, usually by a call to
 307         <<bfd_get_reloc_upper_bound>>.
 308
 309         The @var{syms} table is also needed for horrible internal magic
 310         reasons.
 311
 312
 313 */
 314 unsigned int
 315 DEFUN(bfd_canonicalize_reloc,(abfd, asect, location, symbols),
 316      bfd *abfd AND
 317      sec_ptr asect AND
 318      arelent **location AND
 319      asymbol **symbols)
 320 {
 321   if (abfd->format != bfd_object) {
 322     bfd_error = invalid_operation;
 323     return 0;
 324   }
 325   return BFD_SEND (abfd, _bfd_canonicalize_reloc,
 326                    (abfd, asect, location, symbols));
 327 }
 328
 329 /*
 330 FUNCTION
 331         bfd_set_reloc
 332
 333 SYNOPSIS
 334         void bfd_set_reloc
 335           (bfd *abfd, asection *sec, arelent **rel, unsigned int count)
 336
 337 DESCRIPTION
 338         Set the relocation pointer and count within
 339         section @var{sec} to the values @var{rel} and @var{count}.
 340         The argument @var{abfd} is ignored.
 341
 342 */
 343 /*ARGSUSED*/
 344 void
 345 bfd_set_reloc (ignore_abfd, asect, location, count)
 346      bfd *ignore_abfd;
 347      sec_ptr asect;
 348      arelent **location;
 349      unsigned int count;
 350 {
 351   asect->orelocation  = location;
 352   asect->reloc_count = count;
 353 }
 354
 355 /*
 356 FUNCTION
 357         bfd_set_file_flags
 358
 359 SYNOPSIS
 360         boolean bfd_set_file_flags(bfd *abfd, flagword flags);
 361
 362 DESCRIPTION
 363         Set the flag word in the BFD @var{abfd} to the value @var{flags}.
 364
 365         Possible errors are:
 366         o <<wrong_format>> - The target bfd was not of object format.
 367         o <<invalid_operation>> - The target bfd was open for reading.
 368         o <<invalid_operation>> -
 369         The flag word contained a bit which was not applicable to the
 370         type of file.  E.g., an attempt was made to set the <<D_PAGED>> bit
 371         on a BFD format which does not support demand paging.
 372
 373 */
 374
 375 boolean
 376 bfd_set_file_flags (abfd, flags)
 377      bfd *abfd;
 378      flagword flags;
 379 {
 380   if (abfd->format != bfd_object) {
 381     bfd_error = wrong_format;
 382     return false;
 383   }
 384
 385   if (bfd_read_p (abfd)) {
 386     bfd_error = invalid_operation;
 387     return false;
 388   }
 389
 390   bfd_get_file_flags (abfd) = flags;
 391   if ((flags & bfd_applicable_file_flags (abfd)) != flags) {
 392     bfd_error = invalid_operation;
 393     return false;
 394   }
 395
 396 return true;
 397 }
 398
 399 void
 400 bfd_assert(file, line)
 401 char *file;
 402 int line;
 403 {
 404   fprintf(stderr, "bfd assertion fail %s:%d\n",file,line);
 405 }
 406
 407
 408 /*
 409 FUNCTION
 410         bfd_set_start_address
 411
 412 SYNOPSIS
 413         boolean bfd_set_start_address(bfd *abfd, bfd_vma vma);
 414
 415 DESCRIPTION
 416         Make @var{vma} the entry point of output BFD @var{abfd}.
 417
 418 RETURNS
 419         Returns <<true>> on success, <<false>> otherwise.
 420 */
 421
 422 boolean
 423 bfd_set_start_address(abfd, vma)
 424 bfd *abfd;
 425 bfd_vma vma;
 426 {
 427   abfd->start_address = vma;
 428   return true;
 429 }
 430
 431
 432 /*
 433 FUNCTION
 434         bfd_get_mtime
 435
 436 SYNOPSIS
 437         long bfd_get_mtime(bfd *abfd);
 438
 439 DESCRIPTION
 440         Return the file modification time (as read from the file system, or
 441         from the archive header for archive members).
 442
 443 */
 444
 445 long
 446 bfd_get_mtime (abfd)
 447      bfd *abfd;
 448 {
 449   FILE *fp;
 450   struct stat buf;
 451
 452   if (abfd->mtime_set)
 453     return abfd->mtime;
 454
 455   fp = bfd_cache_lookup (abfd);
 456   if (0 != fstat (fileno (fp), &buf))
 457     return 0;
 458
 459   abfd->mtime = buf.st_mtime;           /* Save value in case anyone wants it */
 460   return buf.st_mtime;
 461 }
 462
 463 /*
 464 FUNCTION
 465         bfd_get_size
 466
 467 SYNOPSIS
 468         long bfd_get_size(bfd *abfd);
 469
 470 DESCRIPTION
 471         Return the file size (as read from file system) for the file
 472         associated with BFD @var{abfd}.
 473
 474         The initial motivation for, and use of, this routine is not
 475         so we can get the exact size of the object the BFD applies to, since
 476         that might not be generally possible (archive members for example).
 477         It would be ideal if someone could eventually modify
 478         it so that such results were guaranteed.
 479
 480         Instead, we want to ask questions like "is this NNN byte sized
 481         object I'm about to try read from file offset YYY reasonable?"
 482         As as example of where we might do this, some object formats
 483         use string tables for which the first <<sizeof(long)>> bytes of the
 484         table contain the size of the table itself, including the size bytes.
 485         If an application tries to read what it thinks is one of these
 486         string tables, without some way to validate the size, and for
 487         some reason the size is wrong (byte swapping error, wrong location
 488         for the string table, etc.), the only clue is likely to be a read
 489         error when it tries to read the table, or a "virtual memory
 490         exhausted" error when it tries to allocate 15 bazillon bytes
 491         of space for the 15 bazillon byte table it is about to read.
 492         This function at least allows us to answer the quesion, "is the
 493         size reasonable?".
 494 */
 495
 496 long
 497 bfd_get_size (abfd)
 498      bfd *abfd;
 499 {
 500   FILE *fp;
 501   struct stat buf;
 502
 503   fp = bfd_cache_lookup (abfd);
 504   if (0 != fstat (fileno (fp), &buf))
 505     return 0;
 506
 507   return buf.st_size;
 508 }
 509
 510 /*
 511 FUNCTION
 512         bfd_get_gp_size
 513
 514 SYNOPSIS
 515         int bfd_get_gp_size(bfd *abfd);
 516
 517 DESCRIPTION
 518         Return the maximum size of objects to be optimized using the GP
 519         register under MIPS ECOFF.  This is typically set by the <<-G>>
 520         argument to the compiler, assembler or linker.
 521 */
 522
 523 int
 524 bfd_get_gp_size (abfd)
 525      bfd *abfd;
 526 {
 527   if (abfd->xvec->flavour == bfd_target_ecoff_flavour)
 528     return ecoff_data (abfd)->gp_size;
 529   else if (abfd->xvec->flavour == bfd_target_elf_flavour)
 530     return elf_gp_size (abfd);
 531   return 0;
 532 }
 533
 534 /*
 535 FUNCTION
 536         bfd_set_gp_size
 537
 538 SYNOPSIS
 539         void bfd_set_gp_size(bfd *abfd, int i);
 540
 541 DESCRIPTION
 542         Set the maximum size of objects to be optimized using the GP
 543         register under ECOFF or MIPS ELF.  This is typically set by
 544         the <<-G>> argument to the compiler, assembler or linker.
 545 */
 546
 547 void
 548 bfd_set_gp_size (abfd, i)
 549      bfd *abfd;
 550      int i;
 551 {
 552   if (abfd->xvec->flavour == bfd_target_ecoff_flavour)
 553     ecoff_data (abfd)->gp_size = i;
 554   else if (abfd->xvec->flavour == bfd_target_elf_flavour)
 555     elf_gp_size (abfd) = i;
 556 }
 557
 558 /*
 559 FUNCTION
 560         bfd_scan_vma
 561
 562 SYNOPSIS
 563         bfd_vma bfd_scan_vma(CONST char *string, CONST char **end, int base);
 564
 565 DESCRIPTION
 566         Convert, like <<strtoul>>, a numerical expression
 567         @var{string} into a <<bfd_vma>> integer, and return that integer.
 568         (Though without as many bells and whistles as <<strtoul>>.)
 569         The expression is assumed to be unsigned (i.e., positive).
 570         If given a @var{base}, it is used as the base for conversion.
 571         A base of 0 causes the function to interpret the string
 572         in hex if a leading "0x" or "0X" is found, otherwise
 573         in octal if a leading zero is found, otherwise in decimal.
 574
 575         Overflow is not detected.
 576 */
 577
 578 bfd_vma
 579 DEFUN(bfd_scan_vma,(string, end, base),
 580       CONST char *string AND
 581       CONST char **end AND
 582       int base)
 583 {
 584   bfd_vma value;
 585   int digit;
 586
 587   /* Let the host do it if possible.  */
 588   if (sizeof(bfd_vma) <= sizeof(unsigned long))
 589     return (bfd_vma) strtoul (string, 0, base);
 590
 591   /* A negative base makes no sense, and we only need to go as high as hex.  */
 592   if ((base < 0) || (base > 16))
 593     return (bfd_vma) 0;
 594
 595   if (base == 0)
 596     {
 597       if (string[0] == '0')
 598         {
 599           if ((string[1] == 'x') || (string[1] == 'X'))
 600             base = 16;
 601           /* XXX should we also allow "0b" or "0B" to set base to 2? */
 602           else
 603             base = 8;
 604         }
 605       else
 606         base = 10;
 607     }
 608   if ((base == 16) &&
 609       (string[0] == '0') && ((string[1] == 'x') || (string[1] == 'X')))
 610     string += 2;
 611   /* XXX should we also skip over "0b" or "0B" if base is 2? */
 612
 613 /* Speed could be improved with a table like hex_value[] in gas.  */
 614 #define HEX_VALUE(c) \
 615   (isxdigit(c) ?                                \
 616     (isdigit(c) ?                               \
 617       (c - '0') :                               \
 618       (10 + c - (islower(c) ? 'a' : 'A'))) :    \
 619     42)
 620
 621   for (value = 0; (digit = HEX_VALUE(*string)) < base; string++)
 622     {
 623       value = value * base + digit;
 624     }
 625
 626   if (end)
 627     *end = string;
 628
 629   return value;
 630 }
 631
 632 /*
 633 FUNCTION
 634         stuff
 635
 636 DESCRIPTION
 637         Stuff which should be documented:
 638
 639 .#define bfd_sizeof_headers(abfd, reloc) \
 640 .     BFD_SEND (abfd, _bfd_sizeof_headers, (abfd, reloc))
 641 .
 642 .#define bfd_find_nearest_line(abfd, sec, syms, off, file, func, line) \
 643 .     BFD_SEND (abfd, _bfd_find_nearest_line,  (abfd, sec, syms, off, file, func, line))
 644 .
 645 .       {* Do these three do anything useful at all, for any back end?  *}
 646 .#define bfd_debug_info_start(abfd) \
 647 .        BFD_SEND (abfd, _bfd_debug_info_start, (abfd))
 648 .
 649 .#define bfd_debug_info_end(abfd) \
 650 .        BFD_SEND (abfd, _bfd_debug_info_end, (abfd))
 651 .
 652 .#define bfd_debug_info_accumulate(abfd, section) \
 653 .        BFD_SEND (abfd, _bfd_debug_info_accumulate, (abfd, section))
 654 .
 655 .
 656 .#define bfd_stat_arch_elt(abfd, stat) \
 657 .        BFD_SEND (abfd, _bfd_stat_arch_elt,(abfd, stat))
 658 .
 659 .#define bfd_set_arch_mach(abfd, arch, mach)\
 660 .        BFD_SEND ( abfd, _bfd_set_arch_mach, (abfd, arch, mach))
 661 .
 662 .#define bfd_get_relocated_section_contents(abfd, link_info, link_order, data, relocateable, symbols) \
 663 .       BFD_SEND (abfd, _bfd_get_relocated_section_contents, \
 664 .                 (abfd, link_info, link_order, data, relocateable, symbols))
 665 .
 666 .#define bfd_relax_section(abfd, section, link_info, symbols) \
 667 .       BFD_SEND (abfd, _bfd_relax_section, \
 668 .                 (abfd, section, link_info, symbols))
 669 .
 670 .#define bfd_link_hash_table_create(abfd) \
 671 .       BFD_SEND (abfd, _bfd_link_hash_table_create, (abfd))
 672 .
 673 .#define bfd_link_add_symbols(abfd, info) \
 674 .       BFD_SEND (abfd, _bfd_link_add_symbols, (abfd, info))
 675 .
 676 .#define bfd_final_link(abfd, info) \
 677 .       BFD_SEND (abfd, _bfd_final_link, (abfd, info))
 678 .
 679
 680 */