bfd/section.c

   1 /* Object file "section" support for the BFD library.
   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         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 .#define SEC_CONSTRUCTOR_TEXT 0x1100
 224 .
 225 .#define SEC_CONSTRUCTOR_DATA 0x2100
 226 .
 227 .#define SEC_CONSTRUCTOR_BSS  0x3100
 228 .
 229 .        {* The section has contents - a data section could be
 230 .           <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>, a debug section could be
 231 .           <<SEC_HAS_CONTENTS>> *}
 232 .
 233 .#define SEC_HAS_CONTENTS 0x200
 234 .
 235 .        {* An instruction to the linker not to output sections
 236 .          containing this flag even if they have information which
 237 .          would normally be written. *}
 238 .
 239 .#define SEC_NEVER_LOAD 0x400
 240 .
 241 .        {* The section is a shared library section.  The linker must leave
 242 .           these completely alone, as the vma and size are used when
 243 .           the executable is loaded. *}
 244 .
 245 .#define SEC_SHARED_LIBRARY 0x800
 246 .
 247 .        {* The section is a common section (symbols may be defined
 248 .           multiple times, the value of a symbol is the amount of
 249 .           space it requires, and the largest symbol value is the one
 250 .           used).  Most targets have exactly one of these (.bss), but
 251 .           ECOFF has two. *}
 252 .
 253 .#define SEC_IS_COMMON 0x8000
 254 .
 255 .   bfd_vma vma;
 256 .   boolean user_set_vma;
 257 .
 258 .        {* The size of the section in bytes, as it will be output.
 259 .           contains a value even if the section has no contents (eg, the
 260 .           size of <<.bss>>). This will be filled in after relocation *}
 261 .
 262 .   bfd_size_type _cooked_size;
 263 .
 264 .        {* The size on disk of the section in bytes originally.  Normally this
 265 .           value is the same as the size, but if some relaxing has
 266 .           been done, then this value will be bigger.  *}
 267 .
 268 .   bfd_size_type _raw_size;
 269 .
 270 .        {* If this section is going to be output, then this value is the
 271 .           offset into the output section of the first byte in the input
 272 .           section. Eg, if this was going to start at the 100th byte in
 273 .           the output section, this value would be 100. *}
 274 .
 275 .   bfd_vma output_offset;
 276 .
 277 .        {* The output section through which to map on output. *}
 278 .
 279 .   struct sec *output_section;
 280 .
 281 .        {* The alignment requirement of the section, as an exponent - eg
 282 .           3 aligns to 2^3 (or 8) *}
 283 .
 284 .   unsigned int alignment_power;
 285 .
 286 .        {* If an input section, a pointer to a vector of relocation
 287 .           records for the data in this section. *}
 288 .
 289 .   struct reloc_cache_entry *relocation;
 290 .
 291 .        {* If an output section, a pointer to a vector of pointers to
 292 .           relocation records for the data in this section. *}
 293 .
 294 .   struct reloc_cache_entry **orelocation;
 295 .
 296 .        {* The number of relocation records in one of the above  *}
 297 .
 298 .   unsigned reloc_count;
 299 .
 300 .        {* Information below is back end specific - and not always used
 301 .           or updated
 302 .
 303 .           File position of section data    *}
 304 .
 305 .   file_ptr filepos;
 306 .
 307 .        {* File position of relocation info *}
 308 .
 309 .   file_ptr rel_filepos;
 310 .
 311 .        {* File position of line data       *}
 312 .
 313 .   file_ptr line_filepos;
 314 .
 315 .        {* Pointer to data for applications *}
 316 .
 317 .   PTR userdata;
 318 .
 319 .   struct lang_output_section *otheruserdata;
 320 .
 321 .        {* Attached line number information *}
 322 .
 323 .   alent *lineno;
 324 .
 325 .        {* Number of line number records   *}
 326 .
 327 .   unsigned int lineno_count;
 328 .
 329 .        {* When a section is being output, this value changes as more
 330 .           linenumbers are written out *}
 331 .
 332 .   file_ptr moving_line_filepos;
 333 .
 334 .        {* what the section number is in the target world  *}
 335 .
 336 .   int target_index;
 337 .
 338 .   PTR used_by_bfd;
 339 .
 340 .        {* If this is a constructor section then here is a list of the
 341 .           relocations created to relocate items within it. *}
 342 .
 343 .   struct relent_chain *constructor_chain;
 344 .
 345 .        {* The BFD which owns the section. *}
 346 .
 347 .   bfd *owner;
 348 .
 349 .   boolean reloc_done;
 350 .        {* A symbol which points at this section only *}
 351 .   struct symbol_cache_entry *symbol;
 352 .   struct symbol_cache_entry **symbol_ptr_ptr;
 353 .   struct bfd_seclet *seclets_head;
 354 .   struct bfd_seclet *seclets_tail;
 355 .} asection ;
 356 .
 357 .
 358 .#define BFD_ABS_SECTION_NAME "*ABS*"
 359 .#define BFD_UND_SECTION_NAME "*UND*"
 360 .#define BFD_COM_SECTION_NAME "*COM*"
 361 .#define BFD_IND_SECTION_NAME "*IND*"
 362 .
 363 .    {* the absolute section *}
 364 . extern   asection bfd_abs_section;
 365 .    {* Pointer to the undefined section *}
 366 . extern   asection bfd_und_section;
 367 .    {* Pointer to the common section *}
 368 . extern asection bfd_com_section;
 369 .    {* Pointer to the indirect section *}
 370 . extern asection bfd_ind_section;
 371 .
 372 . extern struct symbol_cache_entry *bfd_abs_symbol;
 373 . extern struct symbol_cache_entry *bfd_com_symbol;
 374 . extern struct symbol_cache_entry *bfd_und_symbol;
 375 . extern struct symbol_cache_entry *bfd_ind_symbol;
 376 .#define bfd_get_section_size_before_reloc(section) \
 377 .     (section->reloc_done ? (abort(),1): (section)->_raw_size)
 378 .#define bfd_get_section_size_after_reloc(section) \
 379 .     ((section->reloc_done) ? (section)->_cooked_size: (abort(),1))
 380 */
 381
 382 /* These symbols are global, not specific to any BFD.  Therefore, anything
 383    that tries to change them is broken, and should be repaired.  */
 384 static CONST asymbol global_syms[] = {
 385   /* the_bfd, name, value, attr, section [, udata] */
 386   { 0, BFD_COM_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_com_section },
 387   { 0, BFD_UND_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_und_section },
 388   { 0, BFD_ABS_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_abs_section },
 389   { 0, BFD_IND_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_ind_section },
 390 };
 391
 392 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
 393   asymbol *SYM = (asymbol *) &global_syms[IDX]; \
 394   asection SEC = { NAME, 0, 0, FLAGS, 0, (boolean) 0, 0, 0, 0, &SEC,\
 395                     0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0, (boolean) 0, \
 396                      (asymbol *) &global_syms[IDX], &SYM, }
 397
 398 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, BFD_COM_SECTION_NAME, 0);
 399 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
 400 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
 401 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
 402 #undef STD_SECTION
 403
 404 /*
 405 DOCDD
 406 INODE
 407 section prototypes,  , typedef asection, Sections
 408 SUBSECTION
 409         section prototypes
 410
 411 These are the functions exported by the section handling part of
 412 <<libbfd>.
 413 */
 414
 415 /*
 416 FUNCTION
 417         bfd_get_section_by_name
 418
 419 SYNOPSIS
 420         asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
 421
 422 DESCRIPTION
 423         Runs through the provided @var{abfd} and returns the
 424         <<asection>> who's name matches that provided, otherwise NULL.
 425         @xref{Sections}, for more information.
 426
 427 */
 428
 429 asection *
 430 DEFUN(bfd_get_section_by_name,(abfd, name),
 431       bfd *abfd AND
 432       CONST char *name)
 433 {
 434   asection *sect;
 435
 436   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 437     if (!strcmp (sect->name, name)) return sect;
 438   return NULL;
 439 }
 440
 441
 442 /*
 443 FUNCTION
 444         bfd_make_section_old_way
 445
 446 SYNOPSIS
 447         asection *bfd_make_section_old_way(bfd *, CONST char *name);
 448
 449 DESCRIPTION
 450         This function creates a new empty section called @var{name}
 451         and attaches it to the end of the chain of sections for the
 452         BFD supplied. An attempt to create a section with a name which
 453         is already in use, returns its pointer without changing the
 454         section chain.
 455
 456         It has the funny name since this is the way it used to be
 457         before is was rewritten...
 458
 459         Possible errors are:
 460         o invalid_operation -
 461         If output has already started for this BFD.
 462         o no_memory -
 463         If obstack alloc fails.
 464
 465 */
 466
 467
 468 asection *
 469 DEFUN(bfd_make_section_old_way,(abfd, name),
 470       bfd *abfd AND
 471       CONST char * name)
 472 {
 473   asection *sec = bfd_get_section_by_name(abfd, name);
 474   if (sec == (asection *)NULL)
 475     {
 476       sec = bfd_make_section(abfd, name);
 477     }
 478   return sec;
 479 }
 480
 481
 482 /*
 483 FUNCTION
 484         bfd_make_section
 485
 486 SYNOPSIS
 487         asection * bfd_make_section(bfd *, CONST char *name);
 488
 489 DESCRIPTION
 490         This function creates a new empty section called @var{name}
 491         and attaches it to the end of the chain of sections for the
 492         BFD supplied. An attempt to create a section with a name which
 493         is already in use, returns NULL without changing the section
 494         chain.
 495
 496         Possible errors are:
 497         o invalid_operation - If output has already started for this BFD.
 498         o no_memory - If obstack alloc fails.
 499 */
 500
 501
 502
 503 sec_ptr
 504 DEFUN(bfd_make_section,(abfd, name),
 505       bfd *abfd AND
 506       CONST char * name)
 507 {
 508   asection *newsect;
 509   asection **  prev = &abfd->sections;
 510   asection * sect = abfd->sections;
 511
 512   if (abfd->output_has_begun) {
 513     bfd_error = invalid_operation;
 514     return NULL;
 515   }
 516
 517   if (strcmp(name, BFD_ABS_SECTION_NAME) == 0)
 518   {
 519     return &bfd_abs_section;
 520   }
 521   if (strcmp(name, BFD_COM_SECTION_NAME) == 0)
 522   {
 523     return &bfd_com_section;
 524   }
 525   if (strcmp(name, BFD_UND_SECTION_NAME) == 0)
 526   {
 527     return &bfd_und_section;
 528   }
 529
 530   if (strcmp(name, BFD_IND_SECTION_NAME) == 0)
 531   {
 532     return &bfd_ind_section;
 533   }
 534
 535   while (sect) {
 536     if (!strcmp(sect->name, name)) return NULL;
 537     prev = &sect->next;
 538     sect = sect->next;
 539   }
 540
 541   newsect = (asection *) bfd_zalloc(abfd, sizeof (asection));
 542   if (newsect == NULL) {
 543     bfd_error = no_memory;
 544     return NULL;
 545   }
 546
 547   newsect->name = name;
 548   newsect->index = abfd->section_count++;
 549   newsect->flags = SEC_NO_FLAGS;
 550
 551   newsect->userdata = 0;
 552   newsect->next = (asection *)NULL;
 553   newsect->relocation = (arelent *)NULL;
 554   newsect->reloc_count = 0;
 555   newsect->line_filepos =0;
 556   newsect->owner = abfd;
 557
 558   /* Create a symbol whos only job is to point to this section. This is
 559      useful for things like relocs which are relative to the base of a
 560      section.  */
 561   newsect->symbol = bfd_make_empty_symbol(abfd);
 562   newsect->symbol->name = name;
 563   newsect->symbol->value = 0;
 564   newsect->symbol->section = newsect;
 565   newsect->symbol->flags = BSF_SECTION_SYM;
 566
 567
 568   newsect->symbol_ptr_ptr = &newsect->symbol;
 569
 570   if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) {
 571     free (newsect);
 572     return NULL;
 573   }
 574
 575   *prev = newsect;
 576   return newsect;
 577 }
 578
 579
 580 /*
 581 FUNCTION
 582         bfd_set_section_flags
 583
 584 SYNOPSIS
 585         boolean bfd_set_section_flags(bfd *, asection *, flagword);
 586
 587 DESCRIPTION
 588         Attempts to set the attributes of the section named in the BFD
 589         supplied to the value. Returns true on success, false on
 590         error. Possible error returns are:
 591
 592         o invalid operation -
 593         The section cannot have one or more of the attributes
 594         requested. For example, a .bss section in <<a.out>> may not
 595         have the <<SEC_HAS_CONTENTS>> field set.
 596
 597 */
 598
 599 boolean
 600 DEFUN(bfd_set_section_flags,(abfd, section, flags),
 601      bfd *abfd AND
 602      sec_ptr section AND
 603      flagword flags)
 604 {
 605 #if 0
 606   /* If you try to copy a text section from an input file (where it
 607      has the SEC_CODE flag set) to an output file, this loses big if
 608      the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
 609      set - which it doesn't, at least not for a.out.  FIXME */
 610
 611   if ((flags & bfd_applicable_section_flags (abfd)) != flags) {
 612     bfd_error = invalid_operation;
 613     return false;
 614   }
 615 #endif
 616
 617   section->flags = flags;
 618   return true;
 619 }
 620
 621
 622 /*
 623 FUNCTION
 624         bfd_map_over_sections
 625
 626 SYNOPSIS
 627         void bfd_map_over_sections(bfd *abfd,
 628                                    void (*func)(bfd *abfd,
 629                                                 asection *sect,
 630                                                 PTR obj),
 631                                    PTR obj);
 632
 633 DESCRIPTION
 634         Calls the provided function @var{func} for each section
 635         attached to the BFD @var{abfd}, passing @var{obj} as an
 636         argument. The function will be called as if by
 637
 638 |       func(abfd, the_section, obj);
 639
 640         This is the prefered method for iterating over sections, an
 641         alternative would be to use a loop:
 642
 643 |          section *p;
 644 |          for (p = abfd->sections; p != NULL; p = p->next)
 645 |             func(abfd, p, ...)
 646
 647
 648 */
 649
 650 /*VARARGS2*/
 651 void
 652 DEFUN(bfd_map_over_sections,(abfd, operation, user_storage),
 653       bfd *abfd AND
 654       void (*operation) PARAMS ((bfd *abfd, asection *sect, PTR obj)) AND
 655       PTR user_storage)
 656 {
 657   asection *sect;
 658   int i = 0;
 659
 660   for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
 661     (*operation) (abfd, sect, user_storage);
 662
 663   if (i != abfd->section_count)         /* Debugging */
 664     abort();
 665 }
 666
 667
 668 /*
 669 FUNCTION
 670         bfd_set_section_size
 671
 672 SYNOPSIS
 673         boolean bfd_set_section_size(bfd *, asection *, bfd_size_type val);
 674
 675 DESCRIPTION
 676         Sets @var{section} to the size @var{val}. If the operation is
 677         ok, then <<true>> is returned, else <<false>>.
 678
 679         Possible error returns:
 680         o invalid_operation -
 681         Writing has started to the BFD, so setting the size is invalid
 682
 683 */
 684
 685 boolean
 686 DEFUN(bfd_set_section_size,(abfd, ptr, val),
 687       bfd *abfd AND
 688       sec_ptr ptr AND
 689       bfd_size_type val)
 690 {
 691   /* Once you've started writing to any section you cannot create or change
 692      the size of any others. */
 693
 694   if (abfd->output_has_begun) {
 695     bfd_error = invalid_operation;
 696     return false;
 697   }
 698
 699   ptr->_cooked_size = val;
 700   ptr->_raw_size = val;
 701
 702   return true;
 703 }
 704
 705 /*
 706 FUNCTION
 707         bfd_set_section_contents
 708
 709 SYNOPSIS
 710         boolean bfd_set_section_contents
 711          (bfd *abfd,
 712          asection *section,
 713          PTR data,
 714          file_ptr offset,
 715          bfd_size_type count);
 716
 717
 718 DESCRIPTION
 719         Sets the contents of the section @var{section} in BFD
 720         @var{abfd} to the data starting in memory at @var{data}. The
 721         data is written to the output section starting at offset
 722         @var{offset} for @var{count} bytes.
 723
 724
 725
 726         Normally <<true>> is returned, else <<false>>. Possible error
 727         returns are:
 728         o no_contents -
 729         The output section does not have the <<SEC_HAS_CONTENTS>>
 730         attribute, so nothing can be written to it.
 731         o and some more too
 732
 733         This routine is front end to the back end function
 734         <<_bfd_set_section_contents>>.
 735
 736
 737 */
 738
 739 #define bfd_get_section_size_now(abfd,sec) \
 740 (sec->reloc_done \
 741  ? bfd_get_section_size_after_reloc (sec) \
 742  : bfd_get_section_size_before_reloc (sec))
 743
 744 boolean
 745 DEFUN(bfd_set_section_contents,(abfd, section, location, offset, count),
 746       bfd *abfd AND
 747       sec_ptr section AND
 748       PTR location AND
 749       file_ptr offset AND
 750       bfd_size_type count)
 751 {
 752   bfd_size_type sz;
 753
 754   if (!bfd_get_section_flags(abfd, section) & SEC_HAS_CONTENTS)
 755       {
 756         bfd_error = no_contents;
 757         return(false);
 758       }
 759
 760   if (offset < 0 || count < 0)
 761     {
 762     bad_val:
 763       bfd_error = bad_value;
 764       return false;
 765     }
 766   sz = bfd_get_section_size_now (abfd, section);
 767   if (offset > sz
 768       || count > sz
 769       || offset + count > sz)
 770     goto bad_val;
 771
 772   if (BFD_SEND (abfd, _bfd_set_section_contents,
 773                 (abfd, section, location, offset, count)))
 774       {
 775         abfd->output_has_begun = true;
 776         return true;
 777       }
 778
 779   return false;
 780 }
 781
 782 /*
 783 FUNCTION
 784         bfd_get_section_contents
 785
 786 SYNOPSIS
 787         boolean bfd_get_section_contents
 788         (bfd *abfd, asection *section, PTR location,
 789          file_ptr offset, bfd_size_type count);
 790
 791 DESCRIPTION
 792         This function reads data from @var{section} in BFD @var{abfd}
 793         into memory starting at @var{location}. The data is read at an
 794         offset of @var{offset} from the start of the input section,
 795         and is read for @var{count} bytes.
 796
 797         If the contents of a constuctor with the <<SEC_CONSTUCTOR>>
 798         flag set are requested, then the @var{location} is filled with
 799         zeroes. If no errors occur, <<true>> is returned, else
 800         <<false>>.
 801
 802
 803
 804 */
 805 boolean
 806 DEFUN(bfd_get_section_contents,(abfd, section, location, offset, count),
 807       bfd *abfd AND
 808       sec_ptr section AND
 809       PTR location AND
 810       file_ptr offset AND
 811       bfd_size_type count)
 812 {
 813   bfd_size_type sz;
 814
 815   if (section->flags & SEC_CONSTRUCTOR)
 816     {
 817       memset(location, 0, (unsigned)count);
 818       return true;
 819     }
 820
 821   if (offset < 0 || count < 0)
 822     {
 823     bad_val:
 824       bfd_error = bad_value;
 825       return false;
 826     }
 827   sz = bfd_get_section_size_now (abfd, section);
 828   if (offset > sz
 829       || count > sz
 830       || offset + count > sz)
 831     goto bad_val;
 832
 833   if (count == 0)
 834     /* Don't bother.  */
 835     return true;
 836
 837   return BFD_SEND (abfd, _bfd_get_section_contents,
 838                    (abfd, section, location, offset, count));
 839 }