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