bfd/section.c

   1 /* Object file "section" support for the BFD library.
   2    Copyright (C) 1990, 1991, 1992, 1993, 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 .       {*  End of section flags.  *}
 273 .
 274 .       {*  The virtual memory address of the section - where it will be
 275 .           at run time.  The symbols are relocated against this.  The
 276 .           user_set_vma flag is maintained by bfd; if it's not set, the
 277 .           backend can assign addresses (for example, in <<a.out>>, where
 278 .           the default address for <<.data>> is dependent on the specific
 279 .           target and various flags).  *}
 280 .
 281 .   bfd_vma vma;
 282 .   boolean user_set_vma;
 283 .
 284 .       {*  The load address of the section - where it would be in a
 285 .           rom image; really only used for writing section header
 286 .           information. *}
 287 .
 288 .   bfd_vma lma;
 289 .
 290 .        {* The size of the section in bytes, as it will be output.
 291 .           contains a value even if the section has no contents (e.g., the
 292 .           size of <<.bss>>). This will be filled in after relocation *}
 293 .
 294 .   bfd_size_type _cooked_size;
 295 .
 296 .        {* The original size on disk of the section, in bytes.  Normally this
 297 .           value is the same as the size, but if some relaxing has
 298 .           been done, then this value will be bigger.  *}
 299 .
 300 .   bfd_size_type _raw_size;
 301 .
 302 .        {* If this section is going to be output, then this value is the
 303 .           offset into the output section of the first byte in the input
 304 .           section. E.g., if this was going to start at the 100th byte in
 305 .           the output section, this value would be 100. *}
 306 .
 307 .   bfd_vma output_offset;
 308 .
 309 .        {* The output section through which to map on output. *}
 310 .
 311 .   struct sec *output_section;
 312 .
 313 .        {* The alignment requirement of the section, as an exponent of 2 -
 314 .           e.g., 3 aligns to 2^3 (or 8). *}
 315 .
 316 .   unsigned int alignment_power;
 317 .
 318 .        {* If an input section, a pointer to a vector of relocation
 319 .           records for the data in this section. *}
 320 .
 321 .   struct reloc_cache_entry *relocation;
 322 .
 323 .        {* If an output section, a pointer to a vector of pointers to
 324 .           relocation records for the data in this section. *}
 325 .
 326 .   struct reloc_cache_entry **orelocation;
 327 .
 328 .        {* The number of relocation records in one of the above  *}
 329 .
 330 .   unsigned reloc_count;
 331 .
 332 .        {* Information below is back end specific - and not always used
 333 .           or updated.  *}
 334 .
 335 .        {* File position of section data    *}
 336 .
 337 .   file_ptr filepos;
 338 .
 339 .        {* File position of relocation info *}
 340 .
 341 .   file_ptr rel_filepos;
 342 .
 343 .        {* File position of line data       *}
 344 .
 345 .   file_ptr line_filepos;
 346 .
 347 .        {* Pointer to data for applications *}
 348 .
 349 .   PTR userdata;
 350 .
 351 .        {* If the SEC_IN_MEMORY flag is set, this points to the actual
 352 .           contents.  *}
 353 .   unsigned char *contents;
 354 .
 355 .        {* Attached line number information *}
 356 .
 357 .   alent *lineno;
 358 .
 359 .        {* Number of line number records   *}
 360 .
 361 .   unsigned int lineno_count;
 362 .
 363 .        {* When a section is being output, this value changes as more
 364 .           linenumbers are written out *}
 365 .
 366 .   file_ptr moving_line_filepos;
 367 .
 368 .        {* What the section number is in the target world  *}
 369 .
 370 .   int target_index;
 371 .
 372 .   PTR used_by_bfd;
 373 .
 374 .        {* If this is a constructor section then here is a list of the
 375 .           relocations created to relocate items within it. *}
 376 .
 377 .   struct relent_chain *constructor_chain;
 378 .
 379 .        {* The BFD which owns the section. *}
 380 .
 381 .   bfd *owner;
 382 .
 383 .   boolean reloc_done;
 384 .        {* A symbol which points at this section only *}
 385 .   struct symbol_cache_entry *symbol;
 386 .   struct symbol_cache_entry **symbol_ptr_ptr;
 387 .
 388 .   struct bfd_link_order *link_order_head;
 389 .   struct bfd_link_order *link_order_tail;
 390 .} asection ;
 391 .
 392 .    {* These sections are global, and are managed by BFD.  The application
 393 .       and target back end are not permitted to change the values in
 394 .       these sections.  New code should use the section_ptr macros rather
 395 .       than referring directly to the const sections.  The const sections
 396 .       may eventually vanish.  *}
 397 .#define BFD_ABS_SECTION_NAME "*ABS*"
 398 .#define BFD_UND_SECTION_NAME "*UND*"
 399 .#define BFD_COM_SECTION_NAME "*COM*"
 400 .#define BFD_IND_SECTION_NAME "*IND*"
 401 .
 402 .    {* the absolute section *}
 403 .extern const asection bfd_abs_section;
 404 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
 405 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
 406 .    {* Pointer to the undefined section *}
 407 .extern const asection bfd_und_section;
 408 .#define bfd_und_section_ptr ((asection *) &bfd_und_section)
 409 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
 410 .    {* Pointer to the common section *}
 411 .extern const asection bfd_com_section;
 412 .#define bfd_com_section_ptr ((asection *) &bfd_com_section)
 413 .    {* Pointer to the indirect section *}
 414 .extern const asection bfd_ind_section;
 415 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
 416 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
 417 .
 418 .extern const struct symbol_cache_entry * const bfd_abs_symbol;
 419 .extern const struct symbol_cache_entry * const bfd_com_symbol;
 420 .extern const struct symbol_cache_entry * const bfd_und_symbol;
 421 .extern const struct symbol_cache_entry * const bfd_ind_symbol;
 422 .#define bfd_get_section_size_before_reloc(section) \
 423 .     (section->reloc_done ? (abort(),1): (section)->_raw_size)
 424 .#define bfd_get_section_size_after_reloc(section) \
 425 .     ((section->reloc_done) ? (section)->_cooked_size: (abort(),1))
 426 */
 427
 428 /* These symbols are global, not specific to any BFD.  Therefore, anything
 429    that tries to change them is broken, and should be repaired.  */
 430 static const asymbol global_syms[] =
 431 {
 432  /* the_bfd, name, value, attr, section [, udata] */
 433   {0, BFD_COM_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_com_section},
 434   {0, BFD_UND_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_und_section},
 435   {0, BFD_ABS_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_abs_section},
 436   {0, BFD_IND_SECTION_NAME, 0, BSF_SECTION_SYM, (asection *) &bfd_ind_section},
 437 };
 438
 439 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
 440   const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \
 441   const asection SEC = \
 442     { NAME, 0, 0, FLAGS, 0, false, 0, 0, 0, 0, (asection *) &SEC, \
 443       0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0, (boolean) 0, \
 444       (asymbol *) &global_syms[IDX], (asymbol **) &SYM, }
 445
 446 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol,
 447              BFD_COM_SECTION_NAME, 0);
 448 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
 449 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
 450 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
 451 #undef STD_SECTION
 452
 453 /*
 454 DOCDD
 455 INODE
 456 section prototypes,  , typedef asection, Sections
 457 SUBSECTION
 458         Section prototypes
 459
 460 These are the functions exported by the section handling part of BFD.
 461 */
 462
 463 /*
 464 FUNCTION
 465         bfd_get_section_by_name
 466
 467 SYNOPSIS
 468         asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
 469
 470 DESCRIPTION
 471         Run through @var{abfd} and return the one of the
 472         <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
 473         @xref{Sections}, for more information.
 474
 475         This should only be used in special cases; the normal way to process
 476         all sections of a given name is to use <<bfd_map_over_sections>> and
 477         <<strcmp>> on the name (or better yet, base it on the section flags
 478         or something else) for each section.
 479 */
 480
 481 asection *
 482 bfd_get_section_by_name (abfd, name)
 483      bfd *abfd;
 484      CONST char *name;
 485 {
 486   asection *sect;
 487
 488   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 489     if (!strcmp (sect->name, name))
 490       return sect;
 491   return NULL;
 492 }
 493
 494
 495 /*
 496 FUNCTION
 497         bfd_make_section_old_way
 498
 499 SYNOPSIS
 500         asection *bfd_make_section_old_way(bfd *abfd, CONST char *name);
 501
 502 DESCRIPTION
 503         Create a new empty section called @var{name}
 504         and attach it to the end of the chain of sections for the
 505         BFD @var{abfd}. An attempt to create a section with a name which
 506         is already in use returns its pointer without changing the
 507         section chain.
 508
 509         It has the funny name since this is the way it used to be
 510         before it was rewritten....
 511
 512         Possible errors are:
 513         o <<bfd_error_invalid_operation>> -
 514         If output has already started for this BFD.
 515         o <<bfd_error_no_memory>> -
 516         If obstack alloc fails.
 517
 518 */
 519
 520
 521 asection *
 522 bfd_make_section_old_way (abfd, name)
 523      bfd *abfd;
 524      CONST char *name;
 525 {
 526   asection *sec = bfd_get_section_by_name (abfd, name);
 527   if (sec == (asection *) NULL)
 528     {
 529       sec = bfd_make_section (abfd, name);
 530     }
 531   return sec;
 532 }
 533
 534 /*
 535 FUNCTION
 536         bfd_make_section_anyway
 537
 538 SYNOPSIS
 539         asection *bfd_make_section_anyway(bfd *abfd, CONST char *name);
 540
 541 DESCRIPTION
 542    Create a new empty section called @var{name} and attach it to the end of
 543    the chain of sections for @var{abfd}.  Create a new section even if there
 544    is already a section with that name.
 545
 546    Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
 547    o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
 548    o <<bfd_error_no_memory>> - If obstack alloc fails.
 549 */
 550
 551 sec_ptr
 552 bfd_make_section_anyway (abfd, name)
 553      bfd *abfd;
 554      CONST char *name;
 555 {
 556   asection *newsect;
 557   asection **prev = &abfd->sections;
 558   asection *sect = abfd->sections;
 559
 560   if (abfd->output_has_begun)
 561     {
 562       bfd_set_error (bfd_error_invalid_operation);
 563       return NULL;
 564     }
 565
 566   while (sect)
 567     {
 568       prev = &sect->next;
 569       sect = sect->next;
 570     }
 571
 572   newsect = (asection *) bfd_zalloc (abfd, sizeof (asection));
 573   if (newsect == NULL)
 574     return NULL;
 575
 576   newsect->name = name;
 577   newsect->index = abfd->section_count++;
 578   newsect->flags = SEC_NO_FLAGS;
 579
 580   newsect->userdata = NULL;
 581   newsect->contents = NULL;
 582   newsect->next = (asection *) NULL;
 583   newsect->relocation = (arelent *) NULL;
 584   newsect->reloc_count = 0;
 585   newsect->line_filepos = 0;
 586   newsect->owner = abfd;
 587
 588   /* Create a symbol whos only job is to point to this section. This is
 589      useful for things like relocs which are relative to the base of a
 590      section.  */
 591   newsect->symbol = bfd_make_empty_symbol (abfd);
 592   if (newsect->symbol == NULL)
 593     return NULL;
 594   newsect->symbol->name = name;
 595   newsect->symbol->value = 0;
 596   newsect->symbol->section = newsect;
 597   newsect->symbol->flags = BSF_SECTION_SYM;
 598
 599   newsect->symbol_ptr_ptr = &newsect->symbol;
 600
 601   if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true)
 602     {
 603       free (newsect);
 604       return NULL;
 605     }
 606
 607   *prev = newsect;
 608   return newsect;
 609 }
 610
 611 /*
 612 FUNCTION
 613         bfd_make_section
 614
 615 SYNOPSIS
 616         asection *bfd_make_section(bfd *, CONST char *name);
 617
 618 DESCRIPTION
 619    Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
 620    bfd_set_error ()) without changing the section chain if there is already a
 621    section named @var{name}.  If there is an error, return <<NULL>> and set
 622    <<bfd_error>>.
 623 */
 624
 625 asection *
 626 bfd_make_section (abfd, name)
 627      bfd *abfd;
 628      CONST char *name;
 629 {
 630   asection *sect = abfd->sections;
 631
 632   if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
 633     {
 634       return bfd_abs_section_ptr;
 635     }
 636   if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
 637     {
 638       return bfd_com_section_ptr;
 639     }
 640   if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
 641     {
 642       return bfd_und_section_ptr;
 643     }
 644
 645   if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
 646     {
 647       return bfd_ind_section_ptr;
 648     }
 649
 650   while (sect)
 651     {
 652       if (!strcmp (sect->name, name))
 653         return NULL;
 654       sect = sect->next;
 655     }
 656
 657   /* The name is not already used; go ahead and make a new section.  */
 658   return bfd_make_section_anyway (abfd, name);
 659 }
 660
 661
 662 /*
 663 FUNCTION
 664         bfd_set_section_flags
 665
 666 SYNOPSIS
 667         boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
 668
 669 DESCRIPTION
 670         Set the attributes of the section @var{sec} in the BFD
 671         @var{abfd} to the value @var{flags}. Return <<true>> on success,
 672         <<false>> on error. Possible error returns are:
 673
 674         o <<bfd_error_invalid_operation>> -
 675         The section cannot have one or more of the attributes
 676         requested. For example, a .bss section in <<a.out>> may not
 677         have the <<SEC_HAS_CONTENTS>> field set.
 678
 679 */
 680
 681 /*ARGSUSED*/
 682 boolean
 683 bfd_set_section_flags (abfd, section, flags)
 684      bfd *abfd;
 685      sec_ptr section;
 686      flagword flags;
 687 {
 688 #if 0
 689   /* If you try to copy a text section from an input file (where it
 690      has the SEC_CODE flag set) to an output file, this loses big if
 691      the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
 692      set - which it doesn't, at least not for a.out.  FIXME */
 693
 694   if ((flags & bfd_applicable_section_flags (abfd)) != flags)
 695     {
 696       bfd_set_error (bfd_error_invalid_operation);
 697       return false;
 698     }
 699 #endif
 700
 701   section->flags = flags;
 702   return true;
 703 }
 704
 705
 706 /*
 707 FUNCTION
 708         bfd_map_over_sections
 709
 710 SYNOPSIS
 711         void bfd_map_over_sections(bfd *abfd,
 712                                    void (*func)(bfd *abfd,
 713                                                 asection *sect,
 714                                                 PTR obj),
 715                                    PTR obj);
 716
 717 DESCRIPTION
 718         Call the provided function @var{func} for each section
 719         attached to the BFD @var{abfd}, passing @var{obj} as an
 720         argument. The function will be called as if by
 721
 722 |       func(abfd, the_section, obj);
 723
 724         This is the prefered method for iterating over sections; an
 725         alternative would be to use a loop:
 726
 727 |          section *p;
 728 |          for (p = abfd->sections; p != NULL; p = p->next)
 729 |             func(abfd, p, ...)
 730
 731
 732 */
 733
 734 /*VARARGS2*/
 735 void
 736 bfd_map_over_sections (abfd, operation, user_storage)
 737      bfd *abfd;
 738      void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj));
 739      PTR user_storage;
 740 {
 741   asection *sect;
 742   unsigned int i = 0;
 743
 744   for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
 745     (*operation) (abfd, sect, user_storage);
 746
 747   if (i != abfd->section_count) /* Debugging */
 748     abort ();
 749 }
 750
 751
 752 /*
 753 FUNCTION
 754         bfd_set_section_size
 755
 756 SYNOPSIS
 757         boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
 758
 759 DESCRIPTION
 760         Set @var{sec} to the size @var{val}. If the operation is
 761         ok, then <<true>> is returned, else <<false>>.
 762
 763         Possible error returns:
 764         o <<bfd_error_invalid_operation>> -
 765         Writing has started to the BFD, so setting the size is invalid.
 766
 767 */
 768
 769 boolean
 770 bfd_set_section_size (abfd, ptr, val)
 771      bfd *abfd;
 772      sec_ptr ptr;
 773      bfd_size_type val;
 774 {
 775   /* Once you've started writing to any section you cannot create or change
 776      the size of any others. */
 777
 778   if (abfd->output_has_begun)
 779     {
 780       bfd_set_error (bfd_error_invalid_operation);
 781       return false;
 782     }
 783
 784   ptr->_cooked_size = val;
 785   ptr->_raw_size = val;
 786
 787   return true;
 788 }
 789
 790 /*
 791 FUNCTION
 792         bfd_set_section_contents
 793
 794 SYNOPSIS
 795         boolean bfd_set_section_contents
 796          (bfd *abfd,
 797          asection *section,
 798          PTR data,
 799          file_ptr offset,
 800          bfd_size_type count);
 801
 802
 803 DESCRIPTION
 804         Sets the contents of the section @var{section} in BFD
 805         @var{abfd} to the data starting in memory at @var{data}. The
 806         data is written to the output section starting at offset
 807         @var{offset} for @var{count} bytes.
 808
 809
 810
 811         Normally <<true>> is returned, else <<false>>. Possible error
 812         returns are:
 813         o <<bfd_error_no_contents>> -
 814         The output section does not have the <<SEC_HAS_CONTENTS>>
 815         attribute, so nothing can be written to it.
 816         o and some more too
 817
 818         This routine is front end to the back end function
 819         <<_bfd_set_section_contents>>.
 820
 821
 822 */
 823
 824 #define bfd_get_section_size_now(abfd,sec) \
 825 (sec->reloc_done \
 826  ? bfd_get_section_size_after_reloc (sec) \
 827  : bfd_get_section_size_before_reloc (sec))
 828
 829 boolean
 830 bfd_set_section_contents (abfd, section, location, offset, count)
 831      bfd *abfd;
 832      sec_ptr section;
 833      PTR location;
 834      file_ptr offset;
 835      bfd_size_type count;
 836 {
 837   bfd_size_type sz;
 838
 839   if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS))
 840     {
 841       bfd_set_error (bfd_error_no_contents);
 842       return (false);
 843     }
 844
 845   if (offset < 0)
 846     {
 847     bad_val:
 848       bfd_set_error (bfd_error_bad_value);
 849       return false;
 850     }
 851   sz = bfd_get_section_size_now (abfd, section);
 852   if ((bfd_size_type) offset > sz
 853       || count > sz
 854       || offset + count > sz)
 855     goto bad_val;
 856
 857   switch (abfd->direction)
 858     {
 859     case read_direction:
 860     case no_direction:
 861       bfd_set_error (bfd_error_invalid_operation);
 862       return false;
 863
 864     case write_direction:
 865       break;
 866
 867     case both_direction:
 868       /* File is opened for update. `output_has_begun' some time ago when
 869            the file was created.  Do not recompute sections sizes or alignments
 870            in _bfd_set_section_content.  */
 871       abfd->output_has_begun = true;
 872       break;
 873     }
 874
 875   if (BFD_SEND (abfd, _bfd_set_section_contents,
 876                 (abfd, section, location, offset, count)))
 877     {
 878       abfd->output_has_begun = true;
 879       return true;
 880     }
 881
 882   return false;
 883 }
 884
 885 /*
 886 FUNCTION
 887         bfd_get_section_contents
 888
 889 SYNOPSIS
 890         boolean bfd_get_section_contents
 891         (bfd *abfd, asection *section, PTR location,
 892          file_ptr offset, bfd_size_type count);
 893
 894 DESCRIPTION
 895         Read data from @var{section} in BFD @var{abfd}
 896         into memory starting at @var{location}. The data is read at an
 897         offset of @var{offset} from the start of the input section,
 898         and is read for @var{count} bytes.
 899
 900         If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
 901         flag set are requested or if the section does not have the
 902         <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
 903         with zeroes. If no errors occur, <<true>> is returned, else
 904         <<false>>.
 905
 906
 907
 908 */
 909 boolean
 910 bfd_get_section_contents (abfd, section, location, offset, count)
 911      bfd *abfd;
 912      sec_ptr section;
 913      PTR location;
 914      file_ptr offset;
 915      bfd_size_type count;
 916 {
 917   bfd_size_type sz;
 918
 919   if (section->flags & SEC_CONSTRUCTOR)
 920     {
 921       memset (location, 0, (unsigned) count);
 922       return true;
 923     }
 924
 925   if (offset < 0)
 926     {
 927     bad_val:
 928       bfd_set_error (bfd_error_bad_value);
 929       return false;
 930     }
 931   /* Even if reloc_done is true, this function reads unrelocated
 932      contents, so we want the raw size.  */
 933   sz = section->_raw_size;
 934   if ((bfd_size_type) offset > sz || count > sz || offset + count > sz)
 935     goto bad_val;
 936
 937   if (count == 0)
 938     /* Don't bother.  */
 939     return true;
 940
 941   if ((section->flags & SEC_HAS_CONTENTS) == 0)
 942     {
 943       memset (location, 0, (unsigned) count);
 944       return true;
 945     }
 946
 947   if ((section->flags & SEC_IN_MEMORY) != 0)
 948     {
 949       memcpy (location, section->contents + offset, (size_t) count);
 950       return true;
 951     }
 952
 953   return BFD_SEND (abfd, _bfd_get_section_contents,
 954                    (abfd, section, location, offset, count));
 955 }
 956
 957 /*
 958 FUNCTION
 959         bfd_copy_private_section_data
 960
 961 SYNOPSIS
 962         boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
 963
 964 DESCRIPTION
 965         Copy private section information from @var{isec} in the BFD
 966         @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
 967         Return <<true>> on success, <<false>> on error.  Possible error
 968         returns are:
 969
 970         o <<bfd_error_no_memory>> -
 971         Not enough memory exists to create private data for @var{osec}.
 972
 973 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
 974 .     BFD_SEND (ibfd, _bfd_copy_private_section_data, \
 975 .               (ibfd, isection, obfd, osection))
 976 */