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         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 shared library section.  The linker must leave
 233 .           these completely alone, as the vma and size are used when
 234 .           the executable is loaded. *}
 235 .#define SEC_SHARED_LIBRARY 0x800
 236 .
 237 .        {* The section is a common section (symbols may be defined
 238 .           multiple times, the value of a symbol is the amount of
 239 .           space it requires, and the largest symbol value is the one
 240 .           used).  Most targets have exactly one of these (which we
 241 .           translate to bfd_com_section), but ECOFF has two. *}
 242 .#define SEC_IS_COMMON 0x8000
 243 .
 244 .        {* The section contains only debugging information.  For
 245 .           example, this is set for ELF .debug and .stab sections.
 246 .           strip tests this flag to see if a section can be
 247 .           discarded. *}
 248 .#define SEC_DEBUGGING 0x10000
 249 .
 250 .       {*  End of section flags.  *}
 251 .
 252 .       {*  The virtual memory address of the section - where it will be
 253 .           at run time.  The symbols are relocated against this.  The
 254 .           user_set_vma flag is maintained by bfd; if it's not set, the
 255 .           backend can assign addresses (for example, in <<a.out>>, where
 256 .           the default address for <<.data>> is dependent on the specific
 257 .           target and various flags).  *}
 258 .
 259 .   bfd_vma vma;
 260 .   boolean user_set_vma;
 261 .
 262 .       {*  The load address of the section - where it would be in a
 263 .           rom image; really only used for writing section header
 264 .           information. *}
 265 .
 266 .   bfd_vma lma;
 267 .
 268 .        {* The size of the section in bytes, as it will be output.
 269 .           contains a value even if the section has no contents (e.g., the
 270 .           size of <<.bss>>). This will be filled in after relocation *}
 271 .
 272 .   bfd_size_type _cooked_size;
 273 .
 274 .        {* The original size on disk of the section, in bytes.  Normally this
 275 .           value is the same as the size, but if some relaxing has
 276 .           been done, then this value will be bigger.  *}
 277 .
 278 .   bfd_size_type _raw_size;
 279 .
 280 .        {* If this section is going to be output, then this value is the
 281 .           offset into the output section of the first byte in the input
 282 .           section. E.g., if this was going to start at the 100th byte in
 283 .           the output section, this value would be 100. *}
 284 .
 285 .   bfd_vma output_offset;
 286 .
 287 .        {* The output section through which to map on output. *}
 288 .
 289 .   struct sec *output_section;
 290 .
 291 .        {* The alignment requirement of the section, as an exponent of 2 -
 292 .           e.g., 3 aligns to 2^3 (or 8). *}
 293 .
 294 .   unsigned int alignment_power;
 295 .
 296 .        {* If an input section, a pointer to a vector of relocation
 297 .           records for the data in this section. *}
 298 .
 299 .   struct reloc_cache_entry *relocation;
 300 .
 301 .        {* If an output section, a pointer to a vector of pointers to
 302 .           relocation records for the data in this section. *}
 303 .
 304 .   struct reloc_cache_entry **orelocation;
 305 .
 306 .        {* The number of relocation records in one of the above  *}
 307 .
 308 .   unsigned reloc_count;
 309 .
 310 .        {* Information below is back end specific - and not always used
 311 .           or updated.  *}
 312 .
 313 .        {* File position of section data    *}
 314 .
 315 .   file_ptr filepos;
 316 .
 317 .        {* File position of relocation info *}
 318 .
 319 .   file_ptr rel_filepos;
 320 .
 321 .        {* File position of line data       *}
 322 .
 323 .   file_ptr line_filepos;
 324 .
 325 .        {* Pointer to data for applications *}
 326 .
 327 .   PTR userdata;
 328 .
 329 .   struct lang_output_section *otheruserdata;
 330 .
 331 .        {* Attached line number information *}
 332 .
 333 .   alent *lineno;
 334 .
 335 .        {* Number of line number records   *}
 336 .
 337 .   unsigned int lineno_count;
 338 .
 339 .        {* When a section is being output, this value changes as more
 340 .           linenumbers are written out *}
 341 .
 342 .   file_ptr moving_line_filepos;
 343 .
 344 .        {* What the section number is in the target world  *}
 345 .
 346 .   int target_index;
 347 .
 348 .   PTR used_by_bfd;
 349 .
 350 .        {* If this is a constructor section then here is a list of the
 351 .           relocations created to relocate items within it. *}
 352 .
 353 .   struct relent_chain *constructor_chain;
 354 .
 355 .        {* The BFD which owns the section. *}
 356 .
 357 .   bfd *owner;
 358 .
 359 .   boolean reloc_done;
 360 .        {* A symbol which points at this section only *}
 361 .   struct symbol_cache_entry *symbol;
 362 .   struct symbol_cache_entry **symbol_ptr_ptr;
 363 .
 364 .   struct bfd_link_order *link_order_head;
 365 .   struct bfd_link_order *link_order_tail;
 366 .} asection ;
 367 .
 368 .
 369 .    {* These sections are global, and are managed by BFD.  The application
 370 .       and target back end are not permitted to change the values in
 371 .       these sections.  *}
 372 .#define BFD_ABS_SECTION_NAME "*ABS*"
 373 .#define BFD_UND_SECTION_NAME "*UND*"
 374 .#define BFD_COM_SECTION_NAME "*COM*"
 375 .#define BFD_IND_SECTION_NAME "*IND*"
 376 .
 377 .    {* the absolute section *}
 378 .extern asection bfd_abs_section;
 379 .    {* Pointer to the undefined section *}
 380 .extern asection bfd_und_section;
 381 .    {* Pointer to the common section *}
 382 .extern asection bfd_com_section;
 383 .    {* Pointer to the indirect section *}
 384 .extern asection bfd_ind_section;
 385 .
 386 .extern struct symbol_cache_entry *bfd_abs_symbol;
 387 .extern struct symbol_cache_entry *bfd_com_symbol;
 388 .extern struct symbol_cache_entry *bfd_und_symbol;
 389 .extern struct symbol_cache_entry *bfd_ind_symbol;
 390 .#define bfd_get_section_size_before_reloc(section) \
 391 .     (section->reloc_done ? (abort(),1): (section)->_raw_size)
 392 .#define bfd_get_section_size_after_reloc(section) \
 393 .     ((section->reloc_done) ? (section)->_cooked_size: (abort(),1))
 394 */
 395
 396 /* These symbols are global, not specific to any BFD.  Therefore, anything
 397    that tries to change them is broken, and should be repaired.  */
 398 static CONST asymbol global_syms[] = {
 399   /* the_bfd, name, value, attr, section [, udata] */
 400   { 0, BFD_COM_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_com_section },
 401   { 0, BFD_UND_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_und_section },
 402   { 0, BFD_ABS_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_abs_section },
 403   { 0, BFD_IND_SECTION_NAME, 0, BSF_SECTION_SYM, &bfd_ind_section },
 404 };
 405
 406 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \
 407   asymbol *SYM = (asymbol *) &global_syms[IDX]; \
 408   asection SEC = { NAME, 0, 0, FLAGS, 0, 0, (boolean) 0, 0, 0, 0, &SEC,\
 409                     0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0, (boolean) 0, \
 410                      (asymbol *) &global_syms[IDX], &SYM, }
 411
 412 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, BFD_COM_SECTION_NAME, 0);
 413 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1);
 414 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2);
 415 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3);
 416 #undef STD_SECTION
 417
 418 /*
 419 DOCDD
 420 INODE
 421 section prototypes,  , typedef asection, Sections
 422 SUBSECTION
 423         Section prototypes
 424
 425 These are the functions exported by the section handling part of BFD.
 426 */
 427
 428 /*
 429 FUNCTION
 430         bfd_get_section_by_name
 431
 432 SYNOPSIS
 433         asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
 434
 435 DESCRIPTION
 436         Run through @var{abfd} and return the one of the
 437         <<asection>>s whose name matches @var{name}, otherwise <<NULL>>.
 438         @xref{Sections}, for more information.
 439
 440         This should only be used in special cases; the normal way to process
 441         all sections of a given name is to use <<bfd_map_over_sections>> and
 442         <<strcmp>> on the name (or better yet, base it on the section flags
 443         or something else) for each section.
 444 */
 445
 446 asection *
 447 DEFUN(bfd_get_section_by_name,(abfd, name),
 448       bfd *abfd AND
 449       CONST char *name)
 450 {
 451   asection *sect;
 452
 453   for (sect = abfd->sections; sect != NULL; sect = sect->next)
 454     if (!strcmp (sect->name, name)) return sect;
 455   return NULL;
 456 }
 457
 458
 459 /*
 460 FUNCTION
 461         bfd_make_section_old_way
 462
 463 SYNOPSIS
 464         asection *bfd_make_section_old_way(bfd *abfd, CONST char *name);
 465
 466 DESCRIPTION
 467         Create a new empty section called @var{name}
 468         and attach it to the end of the chain of sections for the
 469         BFD @var{abfd}. An attempt to create a section with a name which
 470         is already in use returns its pointer without changing the
 471         section chain.
 472
 473         It has the funny name since this is the way it used to be
 474         before it was rewritten....
 475
 476         Possible errors are:
 477         o <<invalid_operation>> -
 478         If output has already started for this BFD.
 479         o <<no_memory>> -
 480         If obstack alloc fails.
 481
 482 */
 483
 484
 485 asection *
 486 DEFUN(bfd_make_section_old_way,(abfd, name),
 487       bfd *abfd AND
 488       CONST char * name)
 489 {
 490   asection *sec = bfd_get_section_by_name(abfd, name);
 491   if (sec == (asection *)NULL)
 492     {
 493       sec = bfd_make_section(abfd, name);
 494     }
 495   return sec;
 496 }
 497
 498 /*
 499 FUNCTION
 500         bfd_make_section_anyway
 501
 502 SYNOPSIS
 503         asection *bfd_make_section_anyway(bfd *abfd, CONST char *name);
 504
 505 DESCRIPTION
 506    Create a new empty section called @var{name} and attach it to the end of
 507    the chain of sections for @var{abfd}.  Create a new section even if there
 508    is already a section with that name.
 509
 510    Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
 511    o <<invalid_operation>> - If output has already started for @var{abfd}.
 512    o <<no_memory>> - If obstack alloc fails.
 513 */
 514
 515 sec_ptr
 516 bfd_make_section_anyway (abfd, name)
 517      bfd *abfd;
 518      CONST char *name;
 519 {
 520   asection *newsect;
 521   asection **prev = &abfd->sections;
 522   asection * sect = abfd->sections;
 523
 524   if (abfd->output_has_begun)
 525     {
 526       bfd_error = invalid_operation;
 527       return NULL;
 528     }
 529
 530   while (sect) {
 531     prev = &sect->next;
 532     sect = sect->next;
 533   }
 534
 535   newsect = (asection *) bfd_zalloc(abfd, sizeof (asection));
 536   if (newsect == NULL) {
 537     bfd_error = no_memory;
 538     return NULL;
 539   }
 540
 541   newsect->name = name;
 542   newsect->index = abfd->section_count++;
 543   newsect->flags = SEC_NO_FLAGS;
 544
 545   newsect->userdata = 0;
 546   newsect->next = (asection *)NULL;
 547   newsect->relocation = (arelent *)NULL;
 548   newsect->reloc_count = 0;
 549   newsect->line_filepos =0;
 550   newsect->owner = abfd;
 551
 552   /* Create a symbol whos only job is to point to this section. This is
 553      useful for things like relocs which are relative to the base of a
 554      section.  */
 555   newsect->symbol = bfd_make_empty_symbol(abfd);
 556   if (!newsect)
 557     return NULL;
 558   newsect->symbol->name = name;
 559   newsect->symbol->value = 0;
 560   newsect->symbol->section = newsect;
 561   newsect->symbol->flags = BSF_SECTION_SYM;
 562
 563   newsect->symbol_ptr_ptr = &newsect->symbol;
 564
 565   if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) {
 566     free (newsect);
 567     return NULL;
 568   }
 569
 570   *prev = newsect;
 571   return newsect;
 572 }
 573
 574 /*
 575 FUNCTION
 576         bfd_make_section
 577
 578 SYNOPSIS
 579         asection *bfd_make_section(bfd *, CONST char *name);
 580
 581 DESCRIPTION
 582    Like <<bfd_make_section_anyway>>, but return <<NULL>> (without setting
 583    bfd_error) without changing the section chain if there is already a
 584    section named @var{name}.  If there is an error, return <<NULL>> and set
 585    <<bfd_error>>.
 586 */
 587
 588 sec_ptr
 589 DEFUN(bfd_make_section,(abfd, name),
 590       bfd *abfd AND
 591       CONST char * name)
 592 {
 593   asection * sect = abfd->sections;
 594
 595   if (strcmp(name, BFD_ABS_SECTION_NAME) == 0)
 596   {
 597     return &bfd_abs_section;
 598   }
 599   if (strcmp(name, BFD_COM_SECTION_NAME) == 0)
 600   {
 601     return &bfd_com_section;
 602   }
 603   if (strcmp(name, BFD_UND_SECTION_NAME) == 0)
 604   {
 605     return &bfd_und_section;
 606   }
 607
 608   if (strcmp(name, BFD_IND_SECTION_NAME) == 0)
 609   {
 610     return &bfd_ind_section;
 611   }
 612
 613   while (sect) {
 614     if (!strcmp(sect->name, name)) return NULL;
 615     sect = sect->next;
 616   }
 617
 618   /* The name is not already used; go ahead and make a new section.  */
 619   return bfd_make_section_anyway (abfd, name);
 620 }
 621
 622
 623 /*
 624 FUNCTION
 625         bfd_set_section_flags
 626
 627 SYNOPSIS
 628         boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
 629
 630 DESCRIPTION
 631         Set the attributes of the section @var{sec} in the BFD
 632         @var{abfd} to the value @var{flags}. Return <<true>> on success,
 633         <<false>> on error. Possible error returns are:
 634
 635         o <<invalid_operation>> -
 636         The section cannot have one or more of the attributes
 637         requested. For example, a .bss section in <<a.out>> may not
 638         have the <<SEC_HAS_CONTENTS>> field set.
 639
 640 */
 641
 642 /*ARGSUSED*/
 643 boolean
 644 DEFUN(bfd_set_section_flags,(abfd, section, flags),
 645      bfd *abfd AND
 646      sec_ptr section AND
 647      flagword flags)
 648 {
 649 #if 0
 650   /* If you try to copy a text section from an input file (where it
 651      has the SEC_CODE flag set) to an output file, this loses big if
 652      the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE
 653      set - which it doesn't, at least not for a.out.  FIXME */
 654
 655   if ((flags & bfd_applicable_section_flags (abfd)) != flags) {
 656     bfd_error = invalid_operation;
 657     return false;
 658   }
 659 #endif
 660
 661   section->flags = flags;
 662   return true;
 663 }
 664
 665
 666 /*
 667 FUNCTION
 668         bfd_map_over_sections
 669
 670 SYNOPSIS
 671         void bfd_map_over_sections(bfd *abfd,
 672                                    void (*func)(bfd *abfd,
 673                                                 asection *sect,
 674                                                 PTR obj),
 675                                    PTR obj);
 676
 677 DESCRIPTION
 678         Call the provided function @var{func} for each section
 679         attached to the BFD @var{abfd}, passing @var{obj} as an
 680         argument. The function will be called as if by
 681
 682 |       func(abfd, the_section, obj);
 683
 684         This is the prefered method for iterating over sections; an
 685         alternative would be to use a loop:
 686
 687 |          section *p;
 688 |          for (p = abfd->sections; p != NULL; p = p->next)
 689 |             func(abfd, p, ...)
 690
 691
 692 */
 693
 694 /*VARARGS2*/
 695 void
 696 DEFUN(bfd_map_over_sections,(abfd, operation, user_storage),
 697       bfd *abfd AND
 698       void (*operation) PARAMS ((bfd *abfd, asection *sect, PTR obj)) AND
 699       PTR user_storage)
 700 {
 701   asection *sect;
 702   int i = 0;
 703
 704   for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
 705     (*operation) (abfd, sect, user_storage);
 706
 707   if (i != abfd->section_count)         /* Debugging */
 708     abort();
 709 }
 710
 711
 712 /*
 713 FUNCTION
 714         bfd_set_section_size
 715
 716 SYNOPSIS
 717         boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
 718
 719 DESCRIPTION
 720         Set @var{sec} to the size @var{val}. If the operation is
 721         ok, then <<true>> is returned, else <<false>>.
 722
 723         Possible error returns:
 724         o <<invalid_operation>> -
 725         Writing has started to the BFD, so setting the size is invalid.
 726
 727 */
 728
 729 boolean
 730 DEFUN(bfd_set_section_size,(abfd, ptr, val),
 731       bfd *abfd AND
 732       sec_ptr ptr AND
 733       bfd_size_type val)
 734 {
 735   /* Once you've started writing to any section you cannot create or change
 736      the size of any others. */
 737
 738   if (abfd->output_has_begun) {
 739     bfd_error = invalid_operation;
 740     return false;
 741   }
 742
 743   ptr->_cooked_size = val;
 744   ptr->_raw_size = val;
 745
 746   return true;
 747 }
 748
 749 /*
 750 FUNCTION
 751         bfd_set_section_contents
 752
 753 SYNOPSIS
 754         boolean bfd_set_section_contents
 755          (bfd *abfd,
 756          asection *section,
 757          PTR data,
 758          file_ptr offset,
 759          bfd_size_type count);
 760
 761
 762 DESCRIPTION
 763         Sets the contents of the section @var{section} in BFD
 764         @var{abfd} to the data starting in memory at @var{data}. The
 765         data is written to the output section starting at offset
 766         @var{offset} for @var{count} bytes.
 767
 768
 769
 770         Normally <<true>> is returned, else <<false>>. Possible error
 771         returns are:
 772         o <<no_contents>> -
 773         The output section does not have the <<SEC_HAS_CONTENTS>>
 774         attribute, so nothing can be written to it.
 775         o and some more too
 776
 777         This routine is front end to the back end function
 778         <<_bfd_set_section_contents>>.
 779
 780
 781 */
 782
 783 #define bfd_get_section_size_now(abfd,sec) \
 784 (sec->reloc_done \
 785  ? bfd_get_section_size_after_reloc (sec) \
 786  : bfd_get_section_size_before_reloc (sec))
 787
 788 boolean
 789 DEFUN(bfd_set_section_contents,(abfd, section, location, offset, count),
 790       bfd *abfd AND
 791       sec_ptr section AND
 792       PTR location AND
 793       file_ptr offset AND
 794       bfd_size_type count)
 795 {
 796   bfd_size_type sz;
 797
 798   if (!bfd_get_section_flags(abfd, section) & SEC_HAS_CONTENTS)
 799       {
 800         bfd_error = no_contents;
 801         return(false);
 802       }
 803
 804   if (offset < 0)
 805     {
 806     bad_val:
 807       bfd_error = bad_value;
 808       return false;
 809     }
 810   sz = bfd_get_section_size_now (abfd, section);
 811   if (offset > sz
 812       || count > sz
 813       || offset + count > sz)
 814     goto bad_val;
 815
 816   switch (abfd->direction)
 817     {
 818       case read_direction:
 819       case no_direction:
 820         bfd_error = invalid_operation;
 821         return false;
 822
 823       case write_direction:
 824         break;
 825
 826       case both_direction:
 827         /* File is opened for update. `output_has_begun' some time ago when
 828            the file was created.  Do not recompute sections sizes or alignments
 829            in _bfd_set_section_content.  */
 830         abfd->output_has_begun = true;
 831         break;
 832     }
 833
 834   if (BFD_SEND (abfd, _bfd_set_section_contents,
 835                 (abfd, section, location, offset, count)))
 836       {
 837         abfd->output_has_begun = true;
 838         return true;
 839       }
 840
 841   return false;
 842 }
 843
 844 /*
 845 FUNCTION
 846         bfd_get_section_contents
 847
 848 SYNOPSIS
 849         boolean bfd_get_section_contents
 850         (bfd *abfd, asection *section, PTR location,
 851          file_ptr offset, bfd_size_type count);
 852
 853 DESCRIPTION
 854         Read data from @var{section} in BFD @var{abfd}
 855         into memory starting at @var{location}. The data is read at an
 856         offset of @var{offset} from the start of the input section,
 857         and is read for @var{count} bytes.
 858
 859         If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
 860         flag set are requested or if the section does not have the
 861         <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
 862         with zeroes. If no errors occur, <<true>> is returned, else
 863         <<false>>.
 864
 865
 866
 867 */
 868 boolean
 869 DEFUN(bfd_get_section_contents,(abfd, section, location, offset, count),
 870       bfd *abfd AND
 871       sec_ptr section AND
 872       PTR location AND
 873       file_ptr offset AND
 874       bfd_size_type count)
 875 {
 876   bfd_size_type sz;
 877
 878   if (section->flags & SEC_CONSTRUCTOR)
 879     {
 880       memset(location, 0, (unsigned)count);
 881       return true;
 882     }
 883
 884   if (offset < 0)
 885     {
 886     bad_val:
 887       bfd_error = bad_value;
 888       return false;
 889     }
 890   /* Even if reloc_done is true, this function reads unrelocated
 891      contents, so we want the raw size.  */
 892   sz = section->_raw_size;
 893   if (offset > sz || count > sz || offset + count > sz)
 894     goto bad_val;
 895
 896   if (count == 0)
 897     /* Don't bother.  */
 898     return true;
 899
 900   if ((section->flags & SEC_HAS_CONTENTS) == 0)
 901     {
 902       memset(location, 0, (unsigned)count);
 903       return true;
 904     }
 905
 906   return BFD_SEND (abfd, _bfd_get_section_contents,
 907                    (abfd, section, location, offset, count));
 908 }