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 <<libbfd>>. 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 .    {* Used by the back end to hold private data. *}
 140 .
 141 .    union
 142 .      {
 143 .      struct aout_data_struct *aout_data;
 144 .      struct artdata *aout_ar_data;
 145 .      struct _oasys_data *oasys_obj_data;
 146 .      struct _oasys_ar_data *oasys_ar_data;
 147 .      struct coff_tdata *coff_obj_data;
 148 .      struct ecoff_tdata *ecoff_obj_data;
 149 .      struct ieee_data_struct *ieee_data;
 150 .      struct ieee_ar_data_struct *ieee_ar_data;
 151 .      struct srec_data_struct *srec_data;
 152 .      struct tekhex_data_struct *tekhex_data;
 153 .      struct elf_obj_tdata *elf_obj_data;
 154 .      struct nlm_obj_tdata *nlm_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 som_data_struct *som_data;
 159 .      struct hpux_core_struct *hpux_core_data;
 160 .      struct sgi_core_struct *sgi_core_data;
 161 .      struct lynx_core_struct *lynx_core_data;
 162 .      struct osf_core_struct *osf_core_data;
 163 .      PTR any;
 164 .      } tdata;
 165 .
 166 .    {* Used by the application to hold private data*}
 167 .    PTR usrdata;
 168 .
 169 .    {* Where all the allocated stuff under this BFD goes *}
 170 .    struct obstack memory;
 171 .
 172 .    {* Is this really needed in addition to usrdata?  *}
 173 .    asymbol **ld_symbols;
 174 .};
 175 .
 176 */
 177
 178 #include "bfd.h"
 179 #include "sysdep.h"
 180 #include "libbfd.h"
 181 #include "coff/internal.h"
 182 #include "coff/sym.h"
 183 #include "libcoff.h"
 184 #include "libecoff.h"
 185 #undef obj_symbols
 186 #include "libelf.h"
 187
 188 #undef strerror
 189 extern char *strerror();
 190
 191 /** Error handling
 192     o - Most functions return nonzero on success (check doc for
 193         precise semantics); 0 or NULL on error.
 194     o - Internal errors are documented by the value of bfd_error.
 195         If that is system_call_error then check errno.
 196     o - The easiest way to report this to the user is to use bfd_perror.
 197 */
 198
 199 bfd_ec bfd_error = no_error;
 200
 201 CONST char *CONST bfd_errmsgs[] = {
 202                         "No error",
 203                         "System call error",
 204                         "Invalid target",
 205                         "File in wrong format",
 206                         "Invalid operation",
 207                         "Memory exhausted",
 208                         "No symbols",
 209                         "No relocation info",
 210                         "No more archived files",
 211                         "Malformed archive",
 212                         "Symbol not found",
 213                         "File format not recognized",
 214                         "File format is ambiguous",
 215                         "Section has no contents",
 216                         "Nonrepresentable section on output",
 217                         "Symbol needs debug section which does not exist",
 218                         "Bad value",
 219                         "File truncated",
 220                         "#<Invalid error code>"
 221                        };
 222
 223 static
 224 void
 225 DEFUN(bfd_nonrepresentable_section,(abfd, name),
 226          CONST  bfd * CONST abfd AND
 227          CONST  char * CONST name)
 228 {
 229   fprintf(stderr,
 230           "bfd error writing file %s, format %s can't represent section %s\n",
 231           abfd->filename,
 232           abfd->xvec->name,
 233           name);
 234   exit(1);
 235 }
 236
 237 /*ARGSUSED*/
 238 static
 239 void
 240 DEFUN(bfd_undefined_symbol,(relent, seclet),
 241       CONST  arelent *relent AND
 242       CONST  struct bfd_seclet *seclet)
 243 {
 244   asymbol *symbol = *(relent->sym_ptr_ptr);
 245   fprintf(stderr, "bfd error relocating, symbol %s is undefined\n",
 246           symbol->name);
 247   exit(1);
 248 }
 249 /*ARGSUSED*/
 250 static
 251 void
 252 DEFUN(bfd_reloc_value_truncated,(relent, seclet),
 253          CONST  arelent *relent AND
 254       struct bfd_seclet *seclet)
 255 {
 256   fprintf(stderr, "bfd error relocating, value truncated\n");
 257   exit(1);
 258 }
 259 /*ARGSUSED*/
 260 static
 261 void
 262 DEFUN(bfd_reloc_is_dangerous,(relent, seclet),
 263       CONST  arelent *relent AND
 264      CONST  struct bfd_seclet *seclet)
 265 {
 266   fprintf(stderr, "bfd error relocating, dangerous\n");
 267   exit(1);
 268 }
 269
 270 bfd_error_vector_type bfd_error_vector =
 271   {
 272   bfd_nonrepresentable_section ,
 273   bfd_undefined_symbol,
 274   bfd_reloc_value_truncated,
 275   bfd_reloc_is_dangerous,
 276   };
 277
 278
 279 CONST char *
 280 bfd_errmsg (error_tag)
 281      bfd_ec error_tag;
 282 {
 283 #ifndef errno
 284   extern int errno;
 285 #endif
 286   if (error_tag == system_call_error)
 287     return strerror (errno);
 288
 289   if ((((int)error_tag <(int) no_error) ||
 290        ((int)error_tag > (int)invalid_error_code)))
 291     error_tag = invalid_error_code;/* sanity check */
 292
 293   return bfd_errmsgs [(int)error_tag];
 294 }
 295
 296 void
 297 DEFUN (bfd_default_error_trap, (error_tag),
 298        bfd_ec error_tag)
 299 {
 300   fprintf(stderr, "bfd assert fail (%s)\n", bfd_errmsg(error_tag));
 301 }
 302
 303 void (*bfd_error_trap) PARAMS ((bfd_ec)) = bfd_default_error_trap;
 304 void (*bfd_error_nonrepresentabltrap) PARAMS ((bfd_ec)) = bfd_default_error_trap;
 305
 306 void
 307 DEFUN(bfd_perror,(message),
 308       CONST char *message)
 309 {
 310   if (bfd_error == system_call_error)
 311     perror((char *)message);            /* must be system error then... */
 312   else {
 313     if (message == NULL || *message == '\0')
 314       fprintf (stderr, "%s\n", bfd_errmsg (bfd_error));
 315     else
 316       fprintf (stderr, "%s: %s\n", message, bfd_errmsg (bfd_error));
 317   }
 318 }
 319
 320
 321 /*
 322 FUNCTION
 323         bfd_set_file_flags
 324
 325 SYNOPSIS
 326         boolean bfd_set_file_flags(bfd *abfd, flagword flags);
 327
 328 DESCRIPTION
 329         Set the flag word in the BFD @var{abfd} to the value @var{flags}.
 330
 331         Possible errors are:
 332         o wrong_format - The target bfd was not of object format.
 333         o invalid_operation - The target bfd was open for reading.
 334         o invalid_operation -
 335         The flag word contained a bit which was not applicable to the
 336         type of file.  E.g., an attempt was made to set the D_PAGED bit
 337         on a bfd format which does not support demand paging.
 338
 339 */
 340
 341 boolean
 342 bfd_set_file_flags (abfd, flags)
 343      bfd *abfd;
 344      flagword flags;
 345 {
 346   if (abfd->format != bfd_object) {
 347     bfd_error = wrong_format;
 348     return false;
 349   }
 350
 351   if (bfd_read_p (abfd)) {
 352     bfd_error = invalid_operation;
 353     return false;
 354   }
 355
 356   bfd_get_file_flags (abfd) = flags;
 357   if ((flags & bfd_applicable_file_flags (abfd)) != flags) {
 358     bfd_error = invalid_operation;
 359     return false;
 360   }
 361
 362 return true;
 363 }
 364
 365 void
 366 bfd_assert(file, line)
 367 char *file;
 368 int line;
 369 {
 370   fprintf(stderr, "bfd assertion fail %s:%d\n",file,line);
 371 }
 372
 373
 374 /*
 375 FUNCTION
 376         bfd_set_start_address
 377
 378 SYNOPSIS
 379         boolean bfd_set_start_address(bfd *abfd, bfd_vma vma);
 380
 381 DESCRIPTION
 382         Make @var{vma} the entry point of output BFD @var{abfd}.
 383
 384 RETURNS
 385         Returns <<true>> on success, <<false>> otherwise.
 386 */
 387
 388 boolean
 389 bfd_set_start_address(abfd, vma)
 390 bfd *abfd;
 391 bfd_vma vma;
 392 {
 393   abfd->start_address = vma;
 394   return true;
 395 }
 396
 397
 398 /*
 399 FUNCTION
 400         bfd_get_mtime
 401
 402 SYNOPSIS
 403         long bfd_get_mtime(bfd *abfd);
 404
 405 DESCRIPTION
 406         Return the file modification time (as read from the file system, or
 407         from the archive header for archive members).
 408
 409 */
 410
 411 long
 412 bfd_get_mtime (abfd)
 413      bfd *abfd;
 414 {
 415   FILE *fp;
 416   struct stat buf;
 417
 418   if (abfd->mtime_set)
 419     return abfd->mtime;
 420
 421   fp = bfd_cache_lookup (abfd);
 422   if (0 != fstat (fileno (fp), &buf))
 423     return 0;
 424
 425   abfd->mtime = buf.st_mtime;           /* Save value in case anyone wants it */
 426   return buf.st_mtime;
 427 }
 428
 429 /*
 430 FUNCTION
 431         bfd_get_size
 432
 433 SYNOPSIS
 434         long bfd_get_size(bfd *abfd);
 435
 436 DESCRIPTION
 437         Return the file size (as read from file system) for the file
 438         associated with BFD @var{abfd}.
 439
 440         The initial motivation for, and use of, this routine is not
 441         so we can get the exact size of the object the BFD applies to, since
 442         that might not be generally possible (archive members for example).
 443         It would be ideal if someone could eventually modify
 444         it so that such results were guaranteed.
 445
 446         Instead, we want to ask questions like "is this NNN byte sized
 447         object I'm about to try read from file offset YYY reasonable?"
 448         As as example of where we might do this, some object formats
 449         use string tables for which the first <<sizeof(long)>> bytes of the
 450         table contain the size of the table itself, including the size bytes.
 451         If an application tries to read what it thinks is one of these
 452         string tables, without some way to validate the size, and for
 453         some reason the size is wrong (byte swapping error, wrong location
 454         for the string table, etc.), the only clue is likely to be a read
 455         error when it tries to read the table, or a "virtual memory
 456         exhausted" error when it tries to allocate 15 bazillon bytes
 457         of space for the 15 bazillon byte table it is about to read.
 458         This function at least allows us to answer the quesion, "is the
 459         size reasonable?".
 460 */
 461
 462 long
 463 bfd_get_size (abfd)
 464      bfd *abfd;
 465 {
 466   FILE *fp;
 467   struct stat buf;
 468
 469   fp = bfd_cache_lookup (abfd);
 470   if (0 != fstat (fileno (fp), &buf))
 471     return 0;
 472
 473   return buf.st_size;
 474 }
 475
 476 /*
 477 FUNCTION
 478         bfd_get_gp_size
 479
 480 SYNOPSIS
 481         int bfd_get_gp_size(bfd *abfd);
 482
 483 DESCRIPTION
 484         Return the maximum size of objects to be optimized using the GP
 485         register under MIPS ECOFF.  This is typically set by the -G
 486         argument to the compiler, assembler or linker.
 487 */
 488
 489 int
 490 bfd_get_gp_size (abfd)
 491      bfd *abfd;
 492 {
 493   if (abfd->xvec->flavour == bfd_target_ecoff_flavour)
 494     return ecoff_data (abfd)->gp_size;
 495   return 0;
 496 }
 497
 498 /*
 499 FUNCTION
 500         bfd_set_gp_size
 501
 502 SYNOPSIS
 503         void bfd_set_gp_size(bfd *abfd, int i);
 504
 505 DESCRIPTION
 506         Set the maximum size of objects to be optimized using the GP
 507         register under ECOFF or MIPS ELF.  This is typically set by
 508         the -G argument to the compiler, assembler or linker.
 509 */
 510
 511 void
 512 bfd_set_gp_size (abfd, i)
 513      bfd *abfd;
 514      int i;
 515 {
 516   if (abfd->xvec->flavour == bfd_target_ecoff_flavour)
 517     ecoff_data (abfd)->gp_size = i;
 518   else if (abfd->xvec->flavour == bfd_target_elf_flavour)
 519     elf_gp_size (abfd) = i;
 520 }
 521
 522 /*
 523 FUNCTION
 524         bfd_scan_vma
 525
 526 SYNOPSIS
 527         bfd_vma bfd_scan_vma(CONST char *string, CONST char **end, int base);
 528
 529 DESCRIPTION
 530         Convert, like <<strtoul>>, a numerical expression
 531         @var{string} into a bfd_vma integer, and returns that integer.
 532         (Though without as many bells and whistles as <<strtoul>>.)
 533         The expression is assumed to be unsigned (i.e. positive).
 534         If given a @var{base}, it is used as the base for conversion.
 535         A base of 0 causes the function to interpret the string
 536         in hex if a leading "0x" or "0X" is found, otherwise
 537         in octal if a leading zero is found, otherwise in decimal.
 538
 539         Overflow is not detected.
 540 */
 541
 542 bfd_vma
 543 DEFUN(bfd_scan_vma,(string, end, base),
 544       CONST char *string AND
 545       CONST char **end AND
 546       int base)
 547 {
 548   bfd_vma value;
 549   int digit;
 550
 551   /* Let the host do it if possible.  */
 552   if (sizeof(bfd_vma) <= sizeof(unsigned long))
 553     return (bfd_vma) strtoul (string, 0, base);
 554
 555   /* A negative base makes no sense, and we only need to go as high as hex.  */
 556   if ((base < 0) || (base > 16))
 557     return (bfd_vma) 0;
 558
 559   if (base == 0)
 560     {
 561       if (string[0] == '0')
 562         {
 563           if ((string[1] == 'x') || (string[1] == 'X'))
 564             base = 16;
 565           /* XXX should we also allow "0b" or "0B" to set base to 2? */
 566           else
 567             base = 8;
 568         }
 569       else
 570         base = 10;
 571     }
 572   if ((base == 16) &&
 573       (string[0] == '0') && ((string[1] == 'x') || (string[1] == 'X')))
 574     string += 2;
 575   /* XXX should we also skip over "0b" or "0B" if base is 2? */
 576
 577 /* Speed could be improved with a table like hex_value[] in gas.  */
 578 #define HEX_VALUE(c) \
 579   (isxdigit(c) ?                                \
 580     (isdigit(c) ?                               \
 581       (c - '0') :                               \
 582       (10 + c - (islower(c) ? 'a' : 'A'))) :    \
 583     42)
 584
 585   for (value = 0; (digit = HEX_VALUE(*string)) < base; string++)
 586     {
 587       value = value * base + digit;
 588     }
 589
 590   if (end)
 591     *end = string;
 592
 593   return value;
 594 }
 595
 596 /*
 597 FUNCTION
 598         stuff
 599
 600 DESCRIPTION
 601         Stuff which should be documented:
 602
 603 .#define bfd_sizeof_headers(abfd, reloc) \
 604 .     BFD_SEND (abfd, _bfd_sizeof_headers, (abfd, reloc))
 605 .
 606 .#define bfd_find_nearest_line(abfd, sec, syms, off, file, func, line) \
 607 .     BFD_SEND (abfd, _bfd_find_nearest_line,  (abfd, sec, syms, off, file, func, line))
 608 .
 609 .       {* Do these three do anything useful at all, for any back end?  *}
 610 .#define bfd_debug_info_start(abfd) \
 611 .        BFD_SEND (abfd, _bfd_debug_info_start, (abfd))
 612 .
 613 .#define bfd_debug_info_end(abfd) \
 614 .        BFD_SEND (abfd, _bfd_debug_info_end, (abfd))
 615 .
 616 .#define bfd_debug_info_accumulate(abfd, section) \
 617 .        BFD_SEND (abfd, _bfd_debug_info_accumulate, (abfd, section))
 618 .
 619 .
 620 .#define bfd_stat_arch_elt(abfd, stat) \
 621 .        BFD_SEND (abfd, _bfd_stat_arch_elt,(abfd, stat))
 622 .
 623 .#define bfd_set_arch_mach(abfd, arch, mach)\
 624 .        BFD_SEND ( abfd, _bfd_set_arch_mach, (abfd, arch, mach))
 625 .
 626 .#define bfd_get_relocated_section_contents(abfd, seclet, data, relocateable) \
 627 .       BFD_SEND (abfd, _bfd_get_relocated_section_contents, (abfd, seclet, data, relocateable))
 628 .
 629 .#define bfd_relax_section(abfd, section, symbols) \
 630 .       BFD_SEND (abfd, _bfd_relax_section, (abfd, section, symbols))
 631 .
 632 .#define bfd_seclet_link(abfd, data, relocateable) \
 633 .       BFD_SEND (abfd, _bfd_seclet_link, (abfd, data, relocateable))
 634
 635 */