bfd/section.c

   1 /* Object file "section" support for the BFD library.
   2    Copyright (C) 1990, 91, 92, 93, 94, 95, 1996 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 /*
  22 SECTION
  23         Sections
  24
  25         The raw data contained within a BFD is maintained through the
  26         section abstraction.  A single BFD may have any number of
  27         sections.  It keeps hold of them by pointing to the first;
  28         each one points to the next in the list.
  29
  30         Sections are supported in BFD in <<section.c>>.
  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         Names need not be unique; for example a COFF file may have several
  52         sections named <<.data>>.
  53
  54         Sometimes a BFD will contain more than the ``natural'' number of
  55         sections. A back end may attach other sections containing
  56         constructor data, or an application may add a section (using
  57         <<bfd_make_section>>) to the sections attached to an already open
  58         BFD. For example, the linker creates an extra section
  59         <<COMMON>> for each input file's BFD to hold information about
  60         common storage.
  61
  62         The raw data is not necessarily read in when
  63         the section descriptor is created. Some targets may leave the
  64         data in place until a <<bfd_get_section_contents>> call is
  65         made. Other back ends may read in all the data at once.  For
  66         example, an S-record file has to be read once to determine the
  67         size of the data. An IEEE-695 file doesn't contain raw data in
  68         sections, but data and relocation expressions intermixed, so
  69         the data area has to be parsed to get out the data and
  70         relocations.
  71
  72 INODE
  73 Section Output, typedef asection, Section Input, Sections
  74
  75 SUBSECTION
  76         Section output
  77
  78         To write a new object style BFD, the various sections to be
  79         written have to be created. They are attached to the BFD in
  80         the same way as input sections; data is written to the
  81         sections using <<bfd_set_section_contents>>.
  82
  83         Any program that creates or combines sections (e.g., the assembler
  84         and linker) must use the <<asection>> fields <<output_section>> and
  85         <<output_offset>> to indicate the file sections to which each
  86         section must be written.  (If the section is being created from
  87         scratch, <<output_section>> should probably point to the section
  88         itself and <<output_offset>> should probably be zero.)
  89
  90         The data to be written comes from input sections attached
  91         (via <<output_section>> pointers) to
  92         the output sections.  The output section structure can be
  93         considered a filter for the input section: the output section
  94         determines the vma of the output data and the name, but the
  95         input section determines the offset into the output section of
  96         the data to be written.
  97
  98         E.g., to create a section "O", starting at 0x100, 0x123 long,
  99         containing two subsections, "A" at offset 0x0 (i.e., at vma
 100         0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>>
 101         structures would look like:
 102
 103 |   section name          "A"
 104 |     output_offset   0x00
 105 |     size            0x20
 106 |     output_section ----------->  section name    "O"
 107 |                             |    vma             0x100
 108 |   section name          "B" |    size            0x123
 109 |     output_offset   0x20    |
 110 |     size            0x103   |
 111 |     output_section  --------|
 112
 113
 114 SUBSECTION
 115         Link orders
 116
 117         The data within a section is stored in a @dfn{link_order}.
 118         These are much like the fixups in <<gas>>.  The link_order
 119         abstraction allows a section to grow and shrink within itself.
 120
 121         A link_order knows how big it is, and which is the next
 122         link_order and where the raw data for it is; it also points to
 123         a list of relocations which apply to it.
 124
 125         The link_order is used by the linker to perform relaxing on
 126         final code.  The compiler creates code which is as big as
 127         necessary to make it work without relaxing, and the user can
 128         select whether to relax.  Sometimes relaxing takes a lot of
 129         time.  The linker runs around the relocations to see if any
 130         are attached to data which can be shrunk, if so it does it on
 131         a link_order by link_order basis.
 132
 133 */
 134
 135
 136 #include "bfd.h"
 137 #include "sysdep.h"
 138 #include "libbfd.h"
 139
 140
 141 /*
 142 DOCDD
 143 INODE
 144 typedef asection, section prototypes, Section Output, Sections
 145 SUBSECTION
 146         typedef asection
 147
 148         Here is the section structure:
 149
 150 CODE_FRAGMENT
 151 .
 152 .typedef struct sec
 153 .{
 154 .        {* The name of the section; the name isn't a copy, the pointer is
 155 .        the same as that passed to bfd_make_section. *}
 156 .
 157 .    CONST char *name;
 158 .
 159 .        {* Which section is it; 0..nth.      *}
 160 .
 161 .   int index;
 162 .
 163 .        {* The next section in the list belonging to the BFD, or NULL. *}
 164 .
 165 .    struct sec *next;
 166 .
 167 .        {* The field flags contains attributes of the section. Some
 168 .           flags are read in from the object file, and some are
 169 .           synthesized from other information.  *}
 170 .
 171 .    flagword flags;
 172 .
 173 .#define SEC_NO_FLAGS   0x000
 174 .
 175 .        {* Tells the OS to allocate space for this section when loading.
 176 .           This is clear for a section containing debug information
 177 .           only. *}
 178 .#define SEC_ALLOC      0x001
 179 .
 180 .        {* Tells the OS to load the section from the file when loading.
 181 .           This is clear for a .bss section. *}
 182 .#define SEC_LOAD       0x002
 183 .
 184 .        {* The section contains data still to be relocated, so there is
 185 .           some relocation information too. *}
 186 .#define SEC_RELOC      0x004
 187 .
 188 .#if 0   {* Obsolete ? *}
 189 .#define SEC_BALIGN     0x008
 190 .#endif
 191 .
 192 .        {* A signal to the OS that the section contains read only
 193 .          data. *}
 194 .#define SEC_READONLY   0x010
 195 .
 196 .        {* The section contains code only. *}
 197 .#define SEC_CODE       0x020
 198 .
 199 .        {* The section contains data only. *}
 200 .#define SEC_DATA       0x040
 201 .
 202 .        {* The section will reside in ROM. *}
 203 .#define SEC_ROM        0x080
 204 .
 205 .        {* The section contains constructor information. This section
 206 .           type is used by the linker to create lists of constructors and
 207 .           destructors used by <<g++>>. When a back end sees a symbol
 208 .           which should be used in a constructor list, it creates a new
 209 .           section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
 210 .           the symbol to it, and builds a relocation. To build the lists
 211 .           of constructors, all the linker has to do is catenate all the
 212 .           sections called <<__CTOR_LIST__>> and relocate the data
 213 .           contained within - exactly the operations it would peform on
 214 .           standard data. *}
 215 .#define SEC_CONSTRUCTOR 0x100
 216 .
 217 .        {* The section is a constuctor, and should be placed at the
 218 .          end of the text, data, or bss section(?). *}
 219 .#define SEC_CONSTRUCTOR_TEXT 0x1100
 220 .#define SEC_CONSTRUCTOR_DATA 0x2100
 221 .#define SEC_CONSTRUCTOR_BSS  0x3100
 222 .
 223 .        {* The section has contents - a data section could be
 224 .           <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
 225 .           <<SEC_HAS_CONTENTS>> *}
 226 .#define SEC_HAS_CONTENTS 0x200
 227 .
 228 .        {* An instruction to the linker to not output the section
 229 .           even if it has information which would normally be written. *}
 230 .#define SEC_NEVER_LOAD 0x400
 231 .
 232 .        {* The section is a COFF shared library section.  This flag is
 233 .           only for the linker.  If this type of section appears in
 234 .           the input file, the linker must copy it to the output file
 235 .           without changing the vma or size.  FIXME: Although this
 236 .           was originally intended to be general, it really is COFF
 237 .           specific (and the flag was renamed to indicate this).  It
 238 .           might be cleaner to have some more general mechanism to
 239 .           allow the back end to control what the linker does with
 240 .           sections. *}
 241 .#define SEC_COFF_SHARED_LIBRARY 0x800
 242 .
 243 .        {* The section is a common section (symbols may be defined
 244 .           multiple times, the value of a symbol is the amount of
 245 .           space it requires, and the largest symbol value is the one
 246 .           used).  Most targets have exactly one of these (which we
 247 .           translate to bfd_com_section_ptr), but ECOFF has two. *}
 248 .#define SEC_IS_COMMON 0x8000
 249 .
 250 .        {* The section contains only debugging information.  For
 251 .           example, this is set for ELF .debug and .stab sections.
 252 .           strip tests this flag to see if a section can be
 253 .           discarded. *}
 254 .#define SEC_DEBUGGING 0x10000
 255 .
 256 .        {* The contents of this section are held in memory pointed to
 257 .           by the contents field.  This is checked by
 258 .           bfd_get_section_contents, and the data is retrieved from
 259 .           memory if appropriate.  *}
 260 .#define SEC_IN_MEMORY 0x20000
 261 .
 262 .        {* The contents of this section are to be excluded by the
 263 .           linker for executable and shared objects unless those
 264 .           objects are to be further relocated.  *}
 265 .#define SEC_EXCLUDE 0x40000
 266 .
 267 .       {* The contents of this section are to be sorted by the
 268 .          based on the address specified in the associated symbol
 269 .          table.  *}
 270 .#define SEC_SORT_ENTRIES 0x80000
 271 .
 272 .       {* A mark flag used by some of the linker backends.  This
 273 .          should not be set by application code.  *}
 274 .#define SEC_LINKER_MARK 0x100000
 275 .
 276 .       {*  End of section flags.  *}
 277 .
 278 .       {*  The virtual memory address of the section - where it will be
 279 .           at run time.  The symbols are relocated against this.  The
 280 .           user_set_vma flag is maintained by bfd; if it's not set, the
 281 .           backend can assign addresses (for example, in <<a.out>>, where
 282 .           the default address for <<.data>> is dependent on the specific
 283 .           target and various flags).  *}
 284 .
 285 .   bfd_vma vma;
 286 .   boolean user_set_vma;
 287 .
 288 .       {*  The load address of the section - where it would be in a
 289 .           rom image; really only used for writing section header
 290 .           information. *}
 291 .
 292 .   bfd_vma lma;
 293 .
 294 .        {* The size of the section in bytes, as it will be output.
 295 .           contains a value even if the section has no contents (e.g., the
 296 .           size of <<.bss>>). This will be filled in after relocation *}
 297 .
 298 .   bfd_size_type _cooked_size;
 299 .
 300 .        {* The original size on disk of the section, in bytes.  Normally this
 301 .           value is the same as the size, but if some relaxing has
 302 .           been done, then this value will be bigger.  *}
 303 .
 304 .   bfd_size_type _raw_size;
 305 .
 306 .        {* If this section is going to be output, then this value is the
 307 .           offset into the output section of the first byte in the input
 308 .           section. E.g., if this was going to start at the 100th byte in
 309 .           the output section, this value would be 100. *}
 310 .
 311 .   bfd_vma output_offset;
 312 .
 313 .        {* The output section through which to map on output. *}
 314 .
 315 .   struct sec *output_section;
 316 .
 317 .        {* The alignment requirement of the section, as an exponent of 2 -
 318 .           e.g., 3 aligns to 2^3 (or 8). *}
 319 .
 320 .   unsigned int alignment_power;
 321 .
 322 .        {* If an input section, a pointer to a vector of relocation
 323 .           records for the data in this section. *}
 324 .
 325 .   struct reloc_cache_entry *relocation;
 326 .
 327 .        {* If an output section, a pointer to a vector of pointers to
 328 .           relocation records for the data in this section. *}
 329 .
 330 .   struct reloc_cache_entry **orelocation;
 331 .
 332 .        {* The number of relocation records in one of the above  *}
 333 .
 334 .   unsigned reloc_count;
 335 .
 336 .        {* Information below is back end specific - and not always used
 337 .           or updated.  *}
 338 .
 339 .        {* File position of section data    *}
 340 .
 341 .   file_ptr filepos;
 342 .
 343 .        {* File position of relocation info *}
 344 .
 345 .   file_ptr rel_filepos;
 346 .
 347 .        {* File position of line data       *}
 348 .
 349 .   file_ptr line_filepos;
 350 .
 351 .        {* Pointer to data for applications *}
 352 .
 353 .   PTR userdata;
 354 .
 355 .        {* If the SEC_IN_MEMORY flag is set, this points to the actual
 356 .           contents.  *}
 357 .   unsigned char *contents;
 358 .
 359 .        {* Attached line number information *}
 360 .
 361 .   alent *lineno;
 362 .
 363 .        {* Number of line number records   *}
 364 .
 365 .   unsigned int lineno_count;
 366 .
 367 .        {* When a section is being output, this value changes as more
 368 .           linenumbers are written out *}
 369 .
 370 .   file_ptr moving_line_filepos;
 371 .
 372 .        {* What the section number is in the target world  *}
 373 .
 374 .   int target_index;
 375 .
 376 .   PTR used_by_bfd;
 377 .
 378 .        {* If this is a constructor section then here is a list of the
 379 .           relocations created to relocate items within it. *}
 380 .
 381 .   struct relent_chain *constructor_chain;
 382 .
 383 .        {* The BFD which owns the section. *}
 384 .
 385 .   bfd *owner;
 386 .
 387 .   boolean reloc_done;
 388 .        {* A symbol which points at this section only *}
 389 .   struct symbol_cache_entry *symbol;
 390 .   struct symbol_cache_entry **symbol_ptr_ptr;
 391 .
 392 .   struct bfd_link_order *link_order_head;
 393 .   struct bfd_link_order *link_order_tail;
 394 .} asection ;
 395 .
 396 .    {* These sections are global, and are managed by BFD.  The application
 397 .       and target back end are not permitted to change the values in
 398 .       these sections.  New code should use the section_ptr macros rather
 399 .       than referring directly to the const sections.  The const sections
 400 .       may eventually vanish.  *}
 401 .#define BFD_ABS_SECTION_NAME "*ABS*"
 402 .#define BFD_UND_SECTION_NAME "*UND*"
 403 .#define BFD_COM_SECTION_NAME "*COM*"
 404 .#define BFD_IND_SECTION_NAME "*IND*"
 405 .
 406 .    {* the absolute section *}
 407 .extern const asection bfd_abs_section;
 408 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
 409 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
 410 .    {* Pointer to the undefined section *}
 411 .extern const asection bfd_und_section;
 412 .#define bfd_und_section_ptr ((asection *) &bfd_und_section)
 413 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
 414 .    {* Pointer to the common section *}
 415 .extern const asection bfd_com_section;
 416 .#define bfd_com_section_ptr ((asection *) &bfd_com_section)
 417 .    {* Pointer to the indirect section *}
 418 .extern const asection bfd_ind_section;
 419 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
 420 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
 421 .
 422 .extern const struct symbol_cache_entry * const bfd_abs_symbol;
 423 .extern const struct symbol_cache_entry * const bfd_com_symbol;
 424 .extern const struct symbol_cache_entry * const bfd_und_symbol;
 425 .extern const struct symbol_cache_entry * const bfd_ind_symbol;
 426 .#define bfd_get_section_size_before_reloc(section) \
 427 .     (section->reloc_done ? (abort(),1): (section)->_raw_size)
 428 .#define bfd_get_section_size_after_reloc(section) \
 429 .     ((section->reloc_done) ? (section)->_cooked_size: (abort(),1))
 430 */
 431
 432 /* These symbols are global, not specific to any BFD.  Therefore, anything
 433    that tries to change them is broken, and should be repaired.  */
 434 static const asymbol global_syms[] =
 435 {
 436  /* the_bfd, name, value, attr, section [, udata] */
 437   {0, BFD_COM_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_com_section},
 438   {0, BFD_UND_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_und_section},
 439   {0, BFD_ABS_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_abs_section},
 440   {0, BFD_IND_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_ind_section},
 441 };
 442
 443 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
 444   const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \
 445   const asection SEC = \
 446     { NAME, 0, 0, FLAGS, 0, false, 0, 0, 0, 0, (asection *) &SEC, \
 447       0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0, (boolean) 0, \
 448       (asymbol *) &global_syms[IDX], (asymbol **) &SYM, }
 449
 450 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol,
 451              BFD_COM_SECTION_NAME, 0);
 452 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
 453 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
 454 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
 455 #undef STD_SECTION
 456
 457 /*
 458 DOCDD
 459 INODE
 460 section prototypes,  , typedef asection, Sections
 461 SUBSECTION
 462         Section prototypes
 463
 464 These are the functions exported by the section handling part of BFD.
 465 */
 466
 467 /*
 468 FUNCTION
 469         bfd_get_section_by_name
 470
 471 SYNOPSIS
 472         asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
 473
 474 DESCRIPTION
 475         Run through @var{abfd} and return the one of the
 476         <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
 477         @xref{Sections}, for more information.
 478
 479         This should only be used in special cases; the normal way to process
 480         all sections of a given name is to use <<bfd_map_over_sections>> and
 481         <<strcmp>> on the name (or better yet, base it on the section flags
 482         or something else) for each section.
 483 */
 484
 485 asection *
 486 bfd_get_section_by_name (abfd, name)
 487      bfd *abfd;
 488      CONST char *name;
 489 {
 490   asection *sect;
 491
 492   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 493     if (!strcmp (sect->name, name))
 494       return sect;
 495   return NULL;
 496 }
 497
 498
 499 /*
 500 FUNCTION
 501         bfd_make_section_old_way
 502
 503 SYNOPSIS
 504         asection *bfd_make_section_old_way(bfd *abfd, CONST char *name);
 505
 506 DESCRIPTION
 507         Create a new empty section called @var{name}
 508         and attach it to the end of the chain of sections for the
 509         BFD @var{abfd}. An attempt to create a section with a name which
 510         is already in use returns its pointer without changing the
 511         section chain.
 512
 513         It has the funny name since this is the way it used to be
 514         before it was rewritten....
 515
 516         Possible errors are:
 517         o <<bfd_error_invalid_operation>> -
 518         If output has already started for this BFD.
 519         o <<bfd_error_no_memory>> -
 520         If obstack alloc fails.
 521
 522 */
 523
 524
 525 asection *
 526 bfd_make_section_old_way (abfd, name)
 527      bfd *abfd;
 528      CONST char *name;
 529 {
 530   asection *sec = bfd_get_section_by_name (abfd, name);
 531   if (sec == (asection *) NULL)
 532     {
 533       sec = bfd_make_section (abfd, name);
 534     }
 535   return sec;
 536 }
 537
 538 /*
 539 FUNCTION
 540         bfd_make_section_anyway
 541
 542 SYNOPSIS
 543         asection *bfd_make_section_anyway(bfd *abfd, CONST char *name);
 544
 545 DESCRIPTION
 546    Create a new empty section called @var{name} and attach it to the end of
 547    the chain of sections for @var{abfd}.  Create a new section even if there
 548    is already a section with that name.
 549
 550    Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
 551    o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
 552    o <<bfd_error_no_memory>> - If obstack alloc fails.
 553 */
 554
 555 sec_ptr
 556 bfd_make_section_anyway (abfd, name)
 557      bfd *abfd;
 558      CONST char *name;
 559 {
 560   asection *newsect;
 561   asection **prev = &abfd->sections;
 562   asection *sect = abfd->sections;
 563
 564   if (abfd->output_has_begun)
 565     {
 566       bfd_set_error (bfd_error_invalid_operation);
 567       return NULL;
 568     }
 569
 570   while (sect)
 571     {
 572       prev = &sect->next;
 573       sect = sect->next;
 574     }
 575
 576   newsect = (asection *) bfd_zalloc (abfd, sizeof (asection));
 577   if (newsect == NULL)
 578     return NULL;
 579
 580   newsect->name = name;
 581   newsect->index = abfd->section_count++;
 582   newsect->flags = SEC_NO_FLAGS;
 583
 584   newsect->userdata = NULL;
 585   newsect->contents = NULL;
 586   newsect->next = (asection *) NULL;
 587   newsect->relocation = (arelent *) NULL;
 588   newsect->reloc_count = 0;
 589   newsect->line_filepos = 0;
 590   newsect->owner = abfd;
 591
 592   /* Create a symbol whos only job is to point to this section. This is
 593      useful for things like relocs which are relative to the base of a
 594      section.  */
 595   newsect->symbol = bfd_make_empty_symbol (abfd);
 596   if (newsect->symbol == NULL)
 597     return NULL;
 598   newsect->symbol->name = name;
 599   newsect->symbol->value = 0;
 600   newsect->symbol->section = newsect;
 601   newsect->symbol->flags = BSF_SECTION_SYM;
 602
 603   newsect->symbol_ptr_ptr = &newsect->symbol;
 604
 605   if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true)
 606     {
 607       free (newsect);
 608       return NULL;
 609     }
 610
 611   *prev = newsect;
 612   return newsect;
 613 }
 614
 615 /*
 616 FUNCTION
 617         bfd_make_section
 618
 619 SYNOPSIS
 620         asection *bfd_make_section(bfd *, CONST char *name);
 621
 622 DESCRIPTION
 623    Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
 624    bfd_set_error ()) without changing the section chain if there is already a
 625    section named @var{name}.  If there is an error, return <<NULL>> and set
 626    <<bfd_error>>.
 627 */
 628
 629 asection *
 630 bfd_make_section (abfd, name)
 631      bfd *abfd;
 632      CONST char *name;
 633 {
 634   asection *sect = abfd->sections;
 635
 636   if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
 637     {
 638       return bfd_abs_section_ptr;
 639     }
 640   if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
 641     {
 642       return bfd_com_section_ptr;
 643     }
 644   if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
 645     {
 646       return bfd_und_section_ptr;
 647     }
 648
 649   if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
 650     {
 651       return bfd_ind_section_ptr;
 652     }
 653
 654   while (sect)
 655     {
 656       if (!strcmp (sect->name, name))
 657         return NULL;
 658       sect = sect->next;
 659     }
 660
 661   /* The name is not already used; go ahead and make a new section.  */
 662   return bfd_make_section_anyway (abfd, name);
 663 }
 664
 665
 666 /*
 667 FUNCTION
 668         bfd_set_section_flags
 669
 670 SYNOPSIS
 671         boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
 672
 673 DESCRIPTION
 674         Set the attributes of the section @var{sec} in the BFD
 675         @var{abfd} to the value @var{flags}. Return <<true>> on success,
 676         <<false>> on error. Possible error returns are:
 677
 678         o <<bfd_error_invalid_operation>> -
 679         The section cannot have one or more of the attributes
 680         requested. For example, a .bss section in <<a.out>> may not
 681         have the <<SEC_HAS_CONTENTS>> field set.
 682
 683 */
 684
 685 /*ARGSUSED*/
 686 boolean
 687 bfd_set_section_flags (abfd, section, flags)
 688      bfd *abfd;
 689      sec_ptr section;
 690      flagword flags;
 691 {
 692 #if 0
 693   /* If you try to copy a text section from an input file (where it
 694      has the SEC_CODE flag set) to an output file, this loses big if
 695      the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
 696      set - which it doesn't, at least not for a.out.  FIXME */
 697
 698   if ((flags & bfd_applicable_section_flags (abfd)) != flags)
 699     {
 700       bfd_set_error (bfd_error_invalid_operation);
 701       return false;
 702     }
 703 #endif
 704
 705   section->flags = flags;
 706   return true;
 707 }
 708
 709
 710 /*
 711 FUNCTION
 712         bfd_map_over_sections
 713
 714 SYNOPSIS
 715         void bfd_map_over_sections(bfd *abfd,
 716                                    void (*func)(bfd *abfd,
 717                                                 asection *sect,
 718                                                 PTR obj),
 719                                    PTR obj);
 720
 721 DESCRIPTION
 722         Call the provided function @var{func} for each section
 723         attached to the BFD @var{abfd}, passing @var{obj} as an
 724         argument. The function will be called as if by
 725
 726 |       func(abfd, the_section, obj);
 727
 728         This is the prefered method for iterating over sections; an
 729         alternative would be to use a loop:
 730
 731 |          section *p;
 732 |          for (p = abfd->sections; p != NULL; p = p->next)
 733 |             func(abfd, p, ...)
 734
 735
 736 */
 737
 738 /*VARARGS2*/
 739 void
 740 bfd_map_over_sections (abfd, operation, user_storage)
 741      bfd *abfd;
 742      void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj));
 743      PTR user_storage;
 744 {
 745   asection *sect;
 746   unsigned int i = 0;
 747
 748   for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
 749     (*operation) (abfd, sect, user_storage);
 750
 751   if (i != abfd->section_count) /* Debugging */
 752     abort ();
 753 }
 754
 755
 756 /*
 757 FUNCTION
 758         bfd_set_section_size
 759
 760 SYNOPSIS
 761         boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
 762
 763 DESCRIPTION
 764         Set @var{sec} to the size @var{val}. If the operation is
 765         ok, then <<true>> is returned, else <<false>>.
 766
 767         Possible error returns:
 768         o <<bfd_error_invalid_operation>> -
 769         Writing has started to the BFD, so setting the size is invalid.
 770
 771 */
 772
 773 boolean
 774 bfd_set_section_size (abfd, ptr, val)
 775      bfd *abfd;
 776      sec_ptr ptr;
 777      bfd_size_type val;
 778 {
 779   /* Once you've started writing to any section you cannot create or change
 780      the size of any others. */
 781
 782   if (abfd->output_has_begun)
 783     {
 784       bfd_set_error (bfd_error_invalid_operation);
 785       return false;
 786     }
 787
 788   ptr->_cooked_size = val;
 789   ptr->_raw_size = val;
 790
 791   return true;
 792 }
 793
 794 /*
 795 FUNCTION
 796         bfd_set_section_contents
 797
 798 SYNOPSIS
 799         boolean bfd_set_section_contents
 800          (bfd *abfd,
 801          asection *section,
 802          PTR data,
 803          file_ptr offset,
 804          bfd_size_type count);
 805
 806
 807 DESCRIPTION
 808         Sets the contents of the section @var{section} in BFD
 809         @var{abfd} to the data starting in memory at @var{data}. The
 810         data is written to the output section starting at offset
 811         @var{offset} for @var{count} bytes.
 812
 813
 814
 815         Normally <<true>> is returned, else <<false>>. Possible error
 816         returns are:
 817         o <<bfd_error_no_contents>> -
 818         The output section does not have the <<SEC_HAS_CONTENTS>>
 819         attribute, so nothing can be written to it.
 820         o and some more too
 821
 822         This routine is front end to the back end function
 823         <<_bfd_set_section_contents>>.
 824
 825
 826 */
 827
 828 #define bfd_get_section_size_now(abfd,sec) \
 829 (sec->reloc_done \
 830  ? bfd_get_section_size_after_reloc (sec) \
 831  : bfd_get_section_size_before_reloc (sec))
 832
 833 boolean
 834 bfd_set_section_contents (abfd, section, location, offset, count)
 835      bfd *abfd;
 836      sec_ptr section;
 837      PTR location;
 838      file_ptr offset;
 839      bfd_size_type count;
 840 {
 841   bfd_size_type sz;
 842
 843   if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
 844     {
 845       bfd_set_error (bfd_error_no_contents);
 846       return (false);
 847     }
 848
 849   if (offset < 0)
 850     {
 851     bad_val:
 852       bfd_set_error (bfd_error_bad_value);
 853       return false;
 854     }
 855   sz = bfd_get_section_size_now (abfd, section);
 856   if ((bfd_size_type) offset > sz
 857       || count > sz
 858       || offset + count > sz)
 859     goto bad_val;
 860
 861   switch (abfd->direction)
 862     {
 863     case read_direction:
 864     case no_direction:
 865       bfd_set_error (bfd_error_invalid_operation);
 866       return false;
 867
 868     case write_direction:
 869       break;
 870
 871     case both_direction:
 872       /* File is opened for update. `output_has_begun' some time ago when
 873            the file was created.  Do not recompute sections sizes or alignments
 874            in _bfd_set_section_content.  */
 875       abfd->output_has_begun = true;
 876       break;
 877     }
 878
 879   if (BFD_SEND (abfd, _bfd_set_section_contents,
 880                 (abfd, section, location, offset, count)))
 881     {
 882       abfd->output_has_begun = true;
 883       return true;
 884     }
 885
 886   return false;
 887 }
 888
 889 /*
 890 FUNCTION
 891         bfd_get_section_contents
 892
 893 SYNOPSIS
 894         boolean bfd_get_section_contents
 895         (bfd *abfd, asection *section, PTR location,
 896          file_ptr offset, bfd_size_type count);
 897
 898 DESCRIPTION
 899         Read data from @var{section} in BFD @var{abfd}
 900         into memory starting at @var{location}. The data is read at an
 901         offset of @var{offset} from the start of the input section,
 902         and is read for @var{count} bytes.
 903
 904         If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
 905         flag set are requested or if the section does not have the
 906         <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
 907         with zeroes. If no errors occur, <<true>> is returned, else
 908         <<false>>.
 909
 910
 911
 912 */
 913 boolean
 914 bfd_get_section_contents (abfd, section, location, offset, count)
 915      bfd *abfd;
 916      sec_ptr section;
 917      PTR location;
 918      file_ptr offset;
 919      bfd_size_type count;
 920 {
 921   bfd_size_type sz;
 922
 923   if (section->flags & SEC_CONSTRUCTOR)
 924     {
 925       memset (location, 0, (unsigned) count);
 926       return true;
 927     }
 928
 929   if (offset < 0)
 930     {
 931     bad_val:
 932       bfd_set_error (bfd_error_bad_value);
 933       return false;
 934     }
 935   /* Even if reloc_done is true, this function reads unrelocated
 936      contents, so we want the raw size.  */
 937   sz = section->_raw_size;
 938   if ((bfd_size_type) offset > sz || count > sz || offset + count > sz)
 939     goto bad_val;
 940
 941   if (count == 0)
 942     /* Don't bother.  */
 943     return true;
 944
 945   if ((section->flags & SEC_HAS_CONTENTS) == 0)
 946     {
 947       memset (location, 0, (unsigned) count);
 948       return true;
 949     }
 950
 951   if ((section->flags & SEC_IN_MEMORY) != 0)
 952     {
 953       memcpy (location, section->contents + offset, (size_t) count);
 954       return true;
 955     }
 956
 957   return BFD_SEND (abfd, _bfd_get_section_contents,
 958                    (abfd, section, location, offset, count));
 959 }
 960
 961 /*
 962 FUNCTION
 963         bfd_copy_private_section_data
 964
 965 SYNOPSIS
 966         boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
 967
 968 DESCRIPTION
 969         Copy private section information from @var{isec} in the BFD
 970         @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
 971         Return <<true>> on success, <<false>> on error.  Possible error
 972         returns are:
 973
 974         o <<bfd_error_no_memory>> -
 975         Not enough memory exists to create private data for @var{osec}.
 976
 977 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
 978 .     BFD_SEND (ibfd, _bfd_copy_private_section_data, \
 979 .               (ibfd, isection, obfd, osection))
 980 */