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