bfd/section.c

   1 /* Object file "section" support for the BFD library.
   2    Copyright (C) 1990-1991 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         Sections
  24
  25         Sections are supported in BFD in <<section.c>>.
  26
  27         The raw data contained within a BFD is maintained through the
  28         section abstraction.  A single BFD may have any number of
  29         sections, and keeps hold of them by pointing to the first,
  30         each one points to the next in the list.
  31
  32 @menu
  33 @* Section Input::
  34 @* Section Output::
  35 @* typedef asection::
  36 @* section prototypes::
  37 @end menu
  38
  39 INODE
  40 Section Input, Section Output, Sections, Sections
  41 SUBSECTION
  42         Section Input
  43
  44         When a BFD is opened for reading, the section structures are
  45         created and attached to the BFD.
  46
  47         Each section has a name which describes the section in the
  48         outside world - for example, <<a.out>> would contain at least
  49         three sections, called <<.text>>, <<.data>> and <<.bss>>.
  50
  51         Sometimes a BFD will contain more than the 'natural' number of
  52         sections. A back end may attach other sections containing
  53         constructor data, or an application may add a section (using
  54         bfd_make_section) to the sections attached to an already open
  55         BFD. For example, the linker creates a supernumary section
  56         <<COMMON>> for each input file's BFD to hold information about
  57         common storage.
  58
  59         The raw data is not necessarily read in at the same time as
  60         the section descriptor is created. Some targets may leave the
  61         data in place until a <<bfd_get_section_contents>> call is
  62         made. Other back ends may read in all the data at once - For
  63         example; an S-record file has to be read once to determine the
  64         size of the data. An IEEE-695 file doesn't contain raw data in
  65         sections, but data and relocation expressions intermixed, so
  66         the data area has to be parsed to get out the data and
  67         relocations.
  68
  69 INODE
  70 Section Output, typedef asection, Section Input, Sections
  71
  72 SUBSECTION
  73         Section Output
  74
  75         To write a new object style BFD, the various sections to be
  76         written have to be created. They are attached to the BFD in
  77         the same way as input sections, data is written to the
  78         sections using <<bfd_set_section_contents>>.
  79
  80         Any program that creates or combines sections (e.g., the assembler
  81         and linker) must use the fields <<output_section>> and
  82         <<output_offset>> to indicate the file sections to which each
  83         section must be written.  (If the section is being created from
  84         scratch, <<output_section>> should probably point to the section
  85         itself, and <<output_offset>> should probably be zero.)
  86
  87         The data to be written comes from input sections attached to
  88         the output sections.  The output section structure can be
  89         considered a filter for the input section, the output section
  90         determines the vma of the output data and the name, but the
  91         input section determines the offset into the output section of
  92         the data to be written.
  93
  94         E.g., to create a section "O", starting at 0x100, 0x123 long,
  95         containing two subsections, "A" at offset 0x0 (ie at vma
  96         0x100) and "B" at offset 0x20 (ie at vma 0x120) the structures
  97         would look like:
  98
  99 |   section name          "A"
 100 |     output_offset   0x00
 101 |     size            0x20
 102 |     output_section ----------->  section name    "O"
 103 |                             |    vma             0x100
 104 |   section name          "B" |    size            0x123
 105 |     output_offset   0x20    |
 106 |     size            0x103   |
 107 |     output_section  --------|
 108
 109
 110 SUBSECTION
 111         Seglets
 112
 113         The data within a section is stored in a <<seglet>>.  These
 114         are much like the fixups in <<gas>>.  The seglet abstraction
 115         allows the a section to grow and shrink within itself.
 116
 117         A seglet knows how big it is, and which is the next seglet and
 118         where the raw data for it is, and also points to a list of
 119         relocations which apply to it.
 120
 121         The seglet is used by the linker to perform relaxing on final
 122         code.  The application creates code which is as big as
 123         necessary to make it work without relaxing, and the user can
 124         select whether to relax.  Sometimes relaxing takes a lot of
 125         time.  The linker runs around the relocations to see if any
 126         are attached to data which can be shrunk, if so it does it on
 127         a seglet by seglet basis.
 128
 129 */
 130
 131
 132 #include "bfd.h"
 133 #include "sysdep.h"
 134 #include "libbfd.h"
 135
 136
 137 /*
 138 DOCDD
 139 INODE
 140 typedef asection, section prototypes, Section Output, Sections
 141 SUBSECTION
 142         typedef asection
 143
 144         The shape of a section struct:
 145
 146 CODE_FRAGMENT
 147 .
 148 .typedef struct sec
 149 .{
 150 .        {* The name of the section, the name isn't a copy, the pointer is
 151 .        the same as that passed to bfd_make_section. *}
 152 .
 153 .    CONST char *name;
 154 .
 155 .
 156 .        {* Which section is it 0.nth      *}
 157 .
 158 .   int index;
 159 .
 160 .        {* The next section in the list belonging to the BFD, or NULL. *}
 161 .
 162 .    struct sec *next;
 163 .
 164 .        {* The field flags contains attributes of the section. Some of
 165 .           flags are read in from the object file, and some are
 166 .           synthesized from other information.  *}
 167 .
 168 .    flagword flags;
 169 .
 170 .#define SEC_NO_FLAGS   0x000
 171 .
 172 .        {* Tells the OS to allocate space for this section when loaded.
 173 .           This would clear for a section containing debug information
 174 .           only. *}
 175 .
 176 .
 177 .#define SEC_ALLOC      0x001
 178 .        {* Tells the OS to load the section from the file when loading.
 179 .           This would be clear for a .bss section *}
 180 .
 181 .#define SEC_LOAD       0x002
 182 .        {* The section contains data still to be relocated, so there will
 183 .           be some relocation information too. *}
 184 .
 185 .#define SEC_RELOC      0x004
 186 .
 187 .        {* Obsolete ? *}
 188 .
 189 .#define SEC_BALIGN     0x008
 190 .
 191 .        {* A signal to the OS that the section contains read only
 192 .          data. *}
 193 .#define SEC_READONLY   0x010
 194 .
 195 .        {* The section contains code only. *}
 196 .
 197 .#define SEC_CODE       0x020
 198 .
 199 .        {* The section contains data only. *}
 200 .
 201 .#define SEC_DATA        0x040
 202 .
 203 .        {* The section will reside in ROM. *}
 204 .
 205 .#define SEC_ROM        0x080
 206 .
 207 .        {* The section contains constructor information. This section
 208 .           type is used by the linker to create lists of constructors and
 209 .           destructors used by <<g++>>. When a back end sees a symbol
 210 .           which should be used in a constructor list, it creates a new
 211 .           section for the type of name (eg <<__CTOR_LIST__>>), attaches
 212 .           the symbol to it and builds a relocation. To build the lists
 213 .           of constructors, all the linker has to to is catenate all the
 214 .           sections called <<__CTOR_LIST__>> and relocte the data
 215 .           contained within - exactly the operations it would peform on
 216 .           standard data. *}
 217 .
 218 .#define SEC_CONSTRUCTOR 0x100
 219 .
 220 .        {* The section is a constuctor, and should be placed at the
 221 .          end of the . *}
 222 .
 223 .
 224 .#define SEC_CONSTRUCTOR_TEXT 0x1100
 225 .
 226 .#define SEC_CONSTRUCTOR_DATA 0x2100
 227 .
 228 .#define SEC_CONSTRUCTOR_BSS  0x3100
 229 .
 230 .
 231 .        {* The section has contents - a bss section could be
 232 .           <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>, a debug section could be
 233 .           <<SEC_HAS_CONTENTS>> *}
 234 .
 235 .#define SEC_HAS_CONTENTS 0x200
 236 .
 237 .        {* An instruction to the linker not to output sections
 238 .          containing this flag even if they have information which
 239 .          would normally be written. *}
 240 .
 241 .#define SEC_NEVER_LOAD 0x400
 242 .
 243 .
 244 .
 245 .   bfd_vma vma;
 246 .   boolean user_set_vma;
 247 .
 248 .        {* The size of the section in bytes, as it will be output.
 249 .           contains a value even if the section has no contents (eg, the
 250 .           size of <<.bss>>). This will be filled in after relocation *}
 251 .
 252 .   bfd_size_type _cooked_size;
 253 .
 254 .        {* The size on disk of the section in bytes originally.  Normally this
 255 .           value is the same as the size, but if some relaxing has
 256 .           been done, then this value will be bigger.  *}
 257 .
 258 .   bfd_size_type _raw_size;
 259 .
 260 .        {* If this section is going to be output, then this value is the
 261 .           offset into the output section of the first byte in the input
 262 .           section. Eg, if this was going to start at the 100th byte in
 263 .           the output section, this value would be 100. *}
 264 .
 265 .   bfd_vma output_offset;
 266 .
 267 .        {* The output section through which to map on output. *}
 268 .
 269 .   struct sec *output_section;
 270 .
 271 .        {* The alignment requirement of the section, as an exponent - eg
 272 .           3 aligns to 2^3 (or 8) *}
 273 .
 274 .   unsigned int alignment_power;
 275 .
 276 .        {* If an input section, a pointer to a vector of relocation
 277 .           records for the data in this section. *}
 278 .
 279 .   struct reloc_cache_entry *relocation;
 280 .
 281 .        {* If an output section, a pointer to a vector of pointers to
 282 .           relocation records for the data in this section. *}
 283 .
 284 .   struct reloc_cache_entry **orelocation;
 285 .
 286 .        {* The number of relocation records in one of the above  *}
 287 .
 288 .   unsigned reloc_count;
 289 .
 290 .        {* Information below is back end specific - and not always used
 291 .           or updated
 292 .
 293 .           File position of section data    *}
 294 .
 295 .   file_ptr filepos;
 296 .
 297 .        {* File position of relocation info *}
 298 .
 299 .   file_ptr rel_filepos;
 300 .
 301 .        {* File position of line data       *}
 302 .
 303 .   file_ptr line_filepos;
 304 .
 305 .        {* Pointer to data for applications *}
 306 .
 307 .   PTR userdata;
 308 .
 309 .   struct lang_output_section *otheruserdata;
 310 .
 311 .        {* Attached line number information *}
 312 .
 313 .   alent *lineno;
 314 .
 315 .        {* Number of line number records   *}
 316 .
 317 .   unsigned int lineno_count;
 318 .
 319 .        {* When a section is being output, this value changes as more
 320 .           linenumbers are written out *}
 321 .
 322 .   file_ptr moving_line_filepos;
 323 .
 324 .        {* what the section number is in the target world  *}
 325 .
 326 .   int target_index;
 327 .
 328 .   PTR used_by_bfd;
 329 .
 330 .        {* If this is a constructor section then here is a list of the
 331 .           relocations created to relocate items within it. *}
 332 .
 333 .   struct relent_chain *constructor_chain;
 334 .
 335 .        {* The BFD which owns the section. *}
 336 .
 337 .   bfd *owner;
 338 .
 339 .   boolean reloc_done;
 340 .        {* A symbol which points at this section only *}
 341 .   struct symbol_cache_entry *symbol;
 342 .   struct symbol_cache_entry **symbol_ptr_ptr;
 343 .   struct bfd_seclet *seclets_head;
 344 .   struct bfd_seclet *seclets_tail;
 345 .} asection ;
 346 .
 347 .
 348 .#define BFD_ABS_SECTION_NAME "*ABS*"
 349 .#define BFD_UND_SECTION_NAME "*UND*"
 350 .#define BFD_COM_SECTION_NAME "*COM*"
 351 .
 352 .    {* the absolute section *}
 353 . extern   asection bfd_abs_section;
 354 .    {* Pointer to the undefined section *}
 355 . extern   asection bfd_und_section;
 356 .    {* Pointer to the common section *}
 357 . extern asection bfd_com_section;
 358 .
 359 . extern struct symbol_cache_entry *bfd_abs_symbol;
 360 . extern struct symbol_cache_entry *bfd_com_symbol;
 361 . extern struct symbol_cache_entry *bfd_und_symbol;
 362 .#define bfd_get_section_size_before_reloc(section) \
 363 .     (section->reloc_done ? (abort(),1): (section)->_raw_size)
 364 .#define bfd_get_section_size_after_reloc(section) \
 365 .     ((section->reloc_done) ? (section)->_cooked_size: (abort(),1))
 366 */
 367
 368 /* These symbols are global, not specific to any BFD.  Therefore, anything
 369    that tries to change them is broken, and should be repaired.  */
 370 static CONST asymbol global_syms[] = {
 371   /* bfd, name, value, attr, section [, udata] */
 372   { 0, BFD_COM_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_com_section },
 373   { 0, BFD_UND_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_und_section },
 374   { 0, BFD_ABS_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_abs_section },
 375 };
 376
 377 #define STD_SECTION(SEC,SYM,NAME, IDX)  \
 378   asymbol *SYM = (asymbol *) &global_syms[IDX]; \
 379   asection SEC = { NAME, 0, 0, 0, 0, (boolean) 0, 0, 0, 0, &SEC,\
 380                     0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0, (boolean) 0, \
 381                      (asymbol *) &global_syms[IDX], &SYM, }
 382
 383 STD_SECTION (bfd_com_section, bfd_com_symbol, BFD_COM_SECTION_NAME, 0);
 384 STD_SECTION (bfd_und_section, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
 385 STD_SECTION (bfd_abs_section, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
 386 #undef STD_SECTION
 387
 388 /*
 389 DOCDD
 390 INODE
 391 section prototypes,  , typedef asection, Sections
 392 SUBSECTION
 393         section prototypes
 394
 395 These are the functions exported by the section handling part of
 396 <<libbfd>.
 397 */
 398
 399 /*
 400 FUNCTION
 401         bfd_get_section_by_name
 402
 403 SYNOPSIS
 404         asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
 405
 406 DESCRIPTION
 407         Runs through the provided @var{abfd} and returns the
 408         <<asection>> who's name matches that provided, otherwise NULL.
 409         @xref{Sections}, for more information.
 410
 411 */
 412
 413 asection *
 414 DEFUN(bfd_get_section_by_name,(abfd, name),
 415       bfd *abfd AND
 416       CONST char *name)
 417 {
 418   asection *sect;
 419
 420   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 421     if (!strcmp (sect->name, name)) return sect;
 422   return NULL;
 423 }
 424
 425
 426 /*
 427 FUNCTION
 428         bfd_make_section_old_way
 429
 430 SYNOPSIS
 431         asection *bfd_make_section_old_way(bfd *, CONST char *name);
 432
 433 DESCRIPTION
 434         This function creates a new empty section called @var{name}
 435         and attaches it to the end of the chain of sections for the
 436         BFD supplied. An attempt to create a section with a name which
 437         is already in use, returns its pointer without changing the
 438         section chain.
 439
 440         It has the funny name since this is the way it used to be
 441         before is was rewritten...
 442
 443         Possible errors are:
 444         o invalid_operation -
 445         If output has already started for this BFD.
 446         o no_memory -
 447         If obstack alloc fails.
 448
 449 */
 450
 451
 452 asection *
 453 DEFUN(bfd_make_section_old_way,(abfd, name),
 454       bfd *abfd AND
 455       CONST char * name)
 456 {
 457   asection *sec = bfd_get_section_by_name(abfd, name);
 458   if (sec == (asection *)NULL)
 459     {
 460       sec = bfd_make_section(abfd, name);
 461     }
 462   return sec;
 463 }
 464
 465
 466 /*
 467 FUNCTION
 468         bfd_make_section
 469
 470 SYNOPSIS
 471         asection * bfd_make_section(bfd *, CONST char *name);
 472
 473 DESCRIPTION
 474         This function creates a new empty section called @var{name}
 475         and attaches it to the end of the chain of sections for the
 476         BFD supplied. An attempt to create a section with a name which
 477         is already in use, returns NULL without changing the section
 478         chain.
 479
 480         Possible errors are:
 481         o invalid_operation - If output has already started for this BFD.
 482         o no_memory - If obstack alloc fails.
 483 */
 484
 485
 486
 487 sec_ptr
 488 DEFUN(bfd_make_section,(abfd, name),
 489       bfd *abfd AND
 490       CONST char * name)
 491 {
 492   asection *newsect;
 493   asection **  prev = &abfd->sections;
 494   asection * sect = abfd->sections;
 495
 496   if (abfd->output_has_begun) {
 497     bfd_error = invalid_operation;
 498     return NULL;
 499   }
 500
 501   if (strcmp(name, BFD_ABS_SECTION_NAME) == 0)
 502   {
 503     return &bfd_abs_section;
 504   }
 505   if (strcmp(name, BFD_COM_SECTION_NAME) == 0)
 506   {
 507     return &bfd_com_section;
 508   }
 509   if (strcmp(name, BFD_UND_SECTION_NAME) == 0)
 510   {
 511     return &bfd_und_section;
 512   }
 513
 514   while (sect) {
 515     if (!strcmp(sect->name, name)) return NULL;
 516     prev = &sect->next;
 517     sect = sect->next;
 518   }
 519
 520   newsect = (asection *) bfd_zalloc(abfd, sizeof (asection));
 521   if (newsect == NULL) {
 522     bfd_error = no_memory;
 523     return NULL;
 524   }
 525
 526   newsect->name = name;
 527   newsect->index = abfd->section_count++;
 528   newsect->flags = SEC_NO_FLAGS;
 529
 530   newsect->userdata = 0;
 531   newsect->next = (asection *)NULL;
 532   newsect->relocation = (arelent *)NULL;
 533   newsect->reloc_count = 0;
 534   newsect->line_filepos =0;
 535   newsect->owner = abfd;
 536
 537   /* Create a symbol whos only job is to point to this section. This is
 538      useful for things like relocs which are relative to the base of a
 539      section.  */
 540   newsect->symbol = bfd_make_empty_symbol(abfd);
 541   newsect->symbol->name = name;
 542   newsect->symbol->value = 0;
 543   newsect->symbol->section = newsect;
 544   newsect->symbol->flags = BSF_SECTION_SYM;
 545
 546
 547   newsect->symbol_ptr_ptr = &newsect->symbol;
 548
 549   if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) {
 550     free (newsect);
 551     return NULL;
 552   }
 553
 554   *prev = newsect;
 555   return newsect;
 556 }
 557
 558
 559 /*
 560 FUNCTION
 561         bfd_set_section_flags
 562
 563 SYNOPSIS
 564         boolean bfd_set_section_flags(bfd *, asection *, flagword);
 565
 566 DESCRIPTION
 567         Attempts to set the attributes of the section named in the BFD
 568         supplied to the value. Returns true on success, false on
 569         error. Possible error returns are:
 570
 571         o invalid operation -
 572         The section cannot have one or more of the attributes
 573         requested. For example, a .bss section in <<a.out>> may not
 574         have the <<SEC_HAS_CONTENTS>> field set.
 575
 576 */
 577
 578 boolean
 579 DEFUN(bfd_set_section_flags,(abfd, section, flags),
 580      bfd *abfd AND
 581      sec_ptr section AND
 582      flagword flags)
 583 {
 584 #if 0
 585   /* If you try to copy a text section from an input file (where it
 586      has the SEC_CODE flag set) to an output file, this loses big if
 587      the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
 588      set - which it doesn't, at least not for a.out.  FIXME */
 589
 590   if ((flags & bfd_applicable_section_flags (abfd)) != flags) {
 591     bfd_error = invalid_operation;
 592     return false;
 593   }
 594 #endif
 595
 596   section->flags = flags;
 597   return true;
 598 }
 599
 600
 601 /*
 602 FUNCTION
 603         bfd_map_over_sections
 604
 605 SYNOPSIS
 606         void bfd_map_over_sections(bfd *abfd,
 607                                    void (*func)(bfd *abfd,
 608                                                 asection *sect,
 609                                                 PTR obj),
 610                                    PTR obj);
 611
 612 DESCRIPTION
 613         Calls the provided function @var{func} for each section
 614         attached to the BFD @var{abfd}, passing @var{obj} as an
 615         argument. The function will be called as if by
 616
 617 |       func(abfd, the_section, obj);
 618
 619         This is the prefered method for iterating over sections, an
 620         alternative would be to use a loop:
 621
 622 |          section *p;
 623 |          for (p = abfd->sections; p != NULL; p = p->next)
 624 |             func(abfd, p, ...)
 625
 626
 627 */
 628
 629 /*VARARGS2*/
 630 void
 631 DEFUN(bfd_map_over_sections,(abfd, operation, user_storage),
 632       bfd *abfd AND
 633       void (*operation) PARAMS ((bfd *abfd, asection *sect, PTR obj)) AND
 634       PTR user_storage)
 635 {
 636   asection *sect;
 637   int i = 0;
 638
 639   for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
 640     (*operation) (abfd, sect, user_storage);
 641
 642   if (i != abfd->section_count)         /* Debugging */
 643     abort();
 644 }
 645
 646
 647 /*
 648 FUNCTION
 649         bfd_set_section_size
 650
 651 SYNOPSIS
 652         boolean bfd_set_section_size(bfd *, asection *, bfd_size_type val);
 653
 654 DESCRIPTION
 655         Sets @var{section} to the size @var{val}. If the operation is
 656         ok, then <<true>> is returned, else <<false>>.
 657
 658         Possible error returns:
 659         o invalid_operation -
 660         Writing has started to the BFD, so setting the size is invalid
 661
 662 */
 663
 664 boolean
 665 DEFUN(bfd_set_section_size,(abfd, ptr, val),
 666       bfd *abfd AND
 667       sec_ptr ptr AND
 668       bfd_size_type val)
 669 {
 670   /* Once you've started writing to any section you cannot create or change
 671      the size of any others. */
 672
 673   if (abfd->output_has_begun) {
 674     bfd_error = invalid_operation;
 675     return false;
 676   }
 677
 678   ptr->_cooked_size = val;
 679   ptr->_raw_size = val;
 680
 681   return true;
 682 }
 683
 684 /*
 685 FUNCTION
 686         bfd_set_section_contents
 687
 688 SYNOPSIS
 689         boolean bfd_set_section_contents
 690          (bfd *abfd,
 691          asection *section,
 692          PTR data,
 693          file_ptr offset,
 694          bfd_size_type count);
 695
 696
 697 DESCRIPTION
 698         Sets the contents of the section @var{section} in BFD
 699         @var{abfd} to the data starting in memory at @var{data}. The
 700         data is written to the output section starting at offset
 701         @var{offset} for @var{count} bytes.
 702
 703
 704
 705         Normally <<true>> is returned, else <<false>>. Possible error
 706         returns are:
 707         o no_contents -
 708         The output section does not have the <<SEC_HAS_CONTENTS>>
 709         attribute, so nothing can be written to it.
 710         o and some more too
 711
 712         This routine is front end to the back end function
 713         <<_bfd_set_section_contents>>.
 714
 715
 716 */
 717
 718 #define bfd_get_section_size_now(abfd,sec) \
 719 (sec->reloc_done \
 720  ? bfd_get_section_size_after_reloc (sec) \
 721  : bfd_get_section_size_before_reloc (sec))
 722
 723 boolean
 724 DEFUN(bfd_set_section_contents,(abfd, section, location, offset, count),
 725       bfd *abfd AND
 726       sec_ptr section AND
 727       PTR location AND
 728       file_ptr offset AND
 729       bfd_size_type count)
 730 {
 731   bfd_size_type sz;
 732
 733   if (!(bfd_get_section_flags(abfd, section) & SEC_HAS_CONTENTS))
 734       {
 735         bfd_error = no_contents;
 736         return(false);
 737       }
 738
 739   if (offset < 0 || count < 0)
 740     {
 741     bad_val:
 742       bfd_error = bad_value;
 743       return false;
 744     }
 745   sz = bfd_get_section_size_now (abfd, section);
 746   if (offset > sz
 747       || count > sz
 748       || offset + count > sz)
 749     goto bad_val;
 750
 751   if (BFD_SEND (abfd, _bfd_set_section_contents,
 752                 (abfd, section, location, offset, count)))
 753       {
 754         abfd->output_has_begun = true;
 755         return true;
 756       }
 757
 758   return false;
 759 }
 760
 761 /*
 762 FUNCTION
 763         bfd_get_section_contents
 764
 765 SYNOPSIS
 766         boolean bfd_get_section_contents
 767         (bfd *abfd, asection *section, PTR location,
 768          file_ptr offset, bfd_size_type count);
 769
 770 DESCRIPTION
 771         This function reads data from @var{section} in BFD @var{abfd}
 772         into memory starting at @var{location}. The data is read at an
 773         offset of @var{offset} from the start of the input section,
 774         and is read for @var{count} bytes.
 775
 776         If the contents of a constuctor with the <<SEC_CONSTUCTOR>>
 777         flag set are requested, then the @var{location} is filled with
 778         zeroes. If no errors occur, <<true>> is returned, else
 779         <<false>>.
 780
 781
 782
 783 */
 784 boolean
 785 DEFUN(bfd_get_section_contents,(abfd, section, location, offset, count),
 786       bfd *abfd AND
 787       sec_ptr section AND
 788       PTR location AND
 789       file_ptr offset AND
 790       bfd_size_type count)
 791 {
 792   bfd_size_type sz;
 793
 794   if (section->flags & SEC_CONSTRUCTOR)
 795     {
 796       memset(location, 0, (unsigned)count);
 797       return true;
 798     }
 799
 800   if (offset < 0 || count < 0)
 801     {
 802     bad_val:
 803       bfd_error = bad_value;
 804       return false;
 805     }
 806   sz = bfd_get_section_size_now (abfd, section);
 807   if (offset > sz
 808       || count > sz
 809       || offset + count > sz)
 810     goto bad_val;
 811
 812   if (count == 0)
 813     /* Don't bother.  */
 814     return true;
 815
 816   return BFD_SEND (abfd, _bfd_get_section_contents,
 817                    (abfd, section, location, offset, count));
 818 }