1@section Sections 2The raw data contained within a BFD is maintained through the 3section abstraction. A single BFD may have any number of 4sections. It keeps hold of them by pointing to the first; 5each one points to the next in the list. 6 7Sections are supported in BFD in @code{section.c}. 8 9@menu 10* Section Input:: 11* Section Output:: 12* typedef asection:: 13* section prototypes:: 14@end menu 15 16@node Section Input, Section Output, Sections, Sections 17@subsection Section input 18When a BFD is opened for reading, the section structures are 19created and attached to the BFD. 20 21Each section has a name which describes the section in the 22outside world---for example, @code{a.out} would contain at least 23three sections, called @code{.text}, @code{.data} and @code{.bss}. 24 25Names need not be unique; for example a COFF file may have several 26sections named @code{.data}. 27 28Sometimes a BFD will contain more than the ``natural'' number of 29sections. A back end may attach other sections containing 30constructor data, or an application may add a section (using 31@code{bfd_make_section}) to the sections attached to an already open 32BFD. For example, the linker creates an extra section 33@code{COMMON} for each input file's BFD to hold information about 34common storage. 35 36The raw data is not necessarily read in when 37the section descriptor is created. Some targets may leave the 38data in place until a @code{bfd_get_section_contents} call is 39made. Other back ends may read in all the data at once. For 40example, an S-record file has to be read once to determine the 41size of the data. An IEEE-695 file doesn't contain raw data in 42sections, but data and relocation expressions intermixed, so 43the data area has to be parsed to get out the data and 44relocations. 45 46@node Section Output, typedef asection, Section Input, Sections 47@subsection Section output 48To write a new object style BFD, the various sections to be 49written have to be created. They are attached to the BFD in 50the same way as input sections; data is written to the 51sections using @code{bfd_set_section_contents}. 52 53Any program that creates or combines sections (e.g., the assembler 54and linker) must use the @code{asection} fields @code{output_section} and 55@code{output_offset} to indicate the file sections to which each 56section must be written. (If the section is being created from 57scratch, @code{output_section} should probably point to the section 58itself and @code{output_offset} should probably be zero.) 59 60The data to be written comes from input sections attached 61(via @code{output_section} pointers) to 62the output sections. The output section structure can be 63considered a filter for the input section: the output section 64determines the vma of the output data and the name, but the 65input section determines the offset into the output section of 66the data to be written. 67 68E.g., to create a section "O", starting at 0x100, 0x123 long, 69containing two subsections, "A" at offset 0x0 (i.e., at vma 700x100) and "B" at offset 0x20 (i.e., at vma 0x120) the @code{asection} 71structures would look like: 72 73@example 74 section name "A" 75 output_offset 0x00 76 size 0x20 77 output_section -----------> section name "O" 78 | vma 0x100 79 section name "B" | size 0x123 80 output_offset 0x20 | 81 size 0x103 | 82 output_section --------| 83@end example 84 85@subsection Link orders 86The data within a section is stored in a @dfn{link_order}. 87These are much like the fixups in @code{gas}. The link_order 88abstraction allows a section to grow and shrink within itself. 89 90A link_order knows how big it is, and which is the next 91link_order and where the raw data for it is; it also points to 92a list of relocations which apply to it. 93 94The link_order is used by the linker to perform relaxing on 95final code. The compiler creates code which is as big as 96necessary to make it work without relaxing, and the user can 97select whether to relax. Sometimes relaxing takes a lot of 98time. The linker runs around the relocations to see if any 99are attached to data which can be shrunk, if so it does it on 100a link_order by link_order basis. 101 102 103@node typedef asection, section prototypes, Section Output, Sections 104@subsection typedef asection 105Here is the section structure: 106 107 108@example 109 110typedef struct bfd_section 111@{ 112 /* The name of the section; the name isn't a copy, the pointer is 113 the same as that passed to bfd_make_section. */ 114 const char *name; 115 116 /* A unique sequence number. */ 117 int id; 118 119 /* Which section in the bfd; 0..n-1 as sections are created in a bfd. */ 120 int index; 121 122 /* The next section in the list belonging to the BFD, or NULL. */ 123 struct bfd_section *next; 124 125 /* The previous section in the list belonging to the BFD, or NULL. */ 126 struct bfd_section *prev; 127 128 /* The field flags contains attributes of the section. Some 129 flags are read in from the object file, and some are 130 synthesized from other information. */ 131 flagword flags; 132 133#define SEC_NO_FLAGS 0x000 134 135 /* Tells the OS to allocate space for this section when loading. 136 This is clear for a section containing debug information only. */ 137#define SEC_ALLOC 0x001 138 139 /* Tells the OS to load the section from the file when loading. 140 This is clear for a .bss section. */ 141#define SEC_LOAD 0x002 142 143 /* The section contains data still to be relocated, so there is 144 some relocation information too. */ 145#define SEC_RELOC 0x004 146 147 /* A signal to the OS that the section contains read only data. */ 148#define SEC_READONLY 0x008 149 150 /* The section contains code only. */ 151#define SEC_CODE 0x010 152 153 /* The section contains data only. */ 154#define SEC_DATA 0x020 155 156 /* The section will reside in ROM. */ 157#define SEC_ROM 0x040 158 159 /* The section contains constructor information. This section 160 type is used by the linker to create lists of constructors and 161 destructors used by @code{g++}. When a back end sees a symbol 162 which should be used in a constructor list, it creates a new 163 section for the type of name (e.g., @code{__CTOR_LIST__}), attaches 164 the symbol to it, and builds a relocation. To build the lists 165 of constructors, all the linker has to do is catenate all the 166 sections called @code{__CTOR_LIST__} and relocate the data 167 contained within - exactly the operations it would peform on 168 standard data. */ 169#define SEC_CONSTRUCTOR 0x080 170 171 /* The section has contents - a data section could be 172 @code{SEC_ALLOC} | @code{SEC_HAS_CONTENTS}; a debug section could be 173 @code{SEC_HAS_CONTENTS} */ 174#define SEC_HAS_CONTENTS 0x100 175 176 /* An instruction to the linker to not output the section 177 even if it has information which would normally be written. */ 178#define SEC_NEVER_LOAD 0x200 179 180 /* The section contains thread local data. */ 181#define SEC_THREAD_LOCAL 0x400 182 183 /* The section has GOT references. This flag is only for the 184 linker, and is currently only used by the elf32-hppa back end. 185 It will be set if global offset table references were detected 186 in this section, which indicate to the linker that the section 187 contains PIC code, and must be handled specially when doing a 188 static link. */ 189#define SEC_HAS_GOT_REF 0x800 190 191 /* The section contains common symbols (symbols may be defined 192 multiple times, the value of a symbol is the amount of 193 space it requires, and the largest symbol value is the one 194 used). Most targets have exactly one of these (which we 195 translate to bfd_com_section_ptr), but ECOFF has two. */ 196#define SEC_IS_COMMON 0x1000 197 198 /* The section contains only debugging information. For 199 example, this is set for ELF .debug and .stab sections. 200 strip tests this flag to see if a section can be 201 discarded. */ 202#define SEC_DEBUGGING 0x2000 203 204 /* The contents of this section are held in memory pointed to 205 by the contents field. This is checked by bfd_get_section_contents, 206 and the data is retrieved from memory if appropriate. */ 207#define SEC_IN_MEMORY 0x4000 208 209 /* The contents of this section are to be excluded by the 210 linker for executable and shared objects unless those 211 objects are to be further relocated. */ 212#define SEC_EXCLUDE 0x8000 213 214 /* The contents of this section are to be sorted based on the sum of 215 the symbol and addend values specified by the associated relocation 216 entries. Entries without associated relocation entries will be 217 appended to the end of the section in an unspecified order. */ 218#define SEC_SORT_ENTRIES 0x10000 219 220 /* When linking, duplicate sections of the same name should be 221 discarded, rather than being combined into a single section as 222 is usually done. This is similar to how common symbols are 223 handled. See SEC_LINK_DUPLICATES below. */ 224#define SEC_LINK_ONCE 0x20000 225 226 /* If SEC_LINK_ONCE is set, this bitfield describes how the linker 227 should handle duplicate sections. */ 228#define SEC_LINK_DUPLICATES 0x40000 229 230 /* This value for SEC_LINK_DUPLICATES means that duplicate 231 sections with the same name should simply be discarded. */ 232#define SEC_LINK_DUPLICATES_DISCARD 0x0 233 234 /* This value for SEC_LINK_DUPLICATES means that the linker 235 should warn if there are any duplicate sections, although 236 it should still only link one copy. */ 237#define SEC_LINK_DUPLICATES_ONE_ONLY 0x80000 238 239 /* This value for SEC_LINK_DUPLICATES means that the linker 240 should warn if any duplicate sections are a different size. */ 241#define SEC_LINK_DUPLICATES_SAME_SIZE 0x100000 242 243 /* This value for SEC_LINK_DUPLICATES means that the linker 244 should warn if any duplicate sections contain different 245 contents. */ 246#define SEC_LINK_DUPLICATES_SAME_CONTENTS \ 247 (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE) 248 249 /* This section was created by the linker as part of dynamic 250 relocation or other arcane processing. It is skipped when 251 going through the first-pass output, trusting that someone 252 else up the line will take care of it later. */ 253#define SEC_LINKER_CREATED 0x200000 254 255 /* This section should not be subject to garbage collection. */ 256#define SEC_KEEP 0x400000 257 258 /* This section contains "short" data, and should be placed 259 "near" the GP. */ 260#define SEC_SMALL_DATA 0x800000 261 262 /* Attempt to merge identical entities in the section. 263 Entity size is given in the entsize field. */ 264#define SEC_MERGE 0x1000000 265 266 /* If given with SEC_MERGE, entities to merge are zero terminated 267 strings where entsize specifies character size instead of fixed 268 size entries. */ 269#define SEC_STRINGS 0x2000000 270 271 /* This section contains data about section groups. */ 272#define SEC_GROUP 0x4000000 273 274 /* The section is a COFF shared library section. This flag is 275 only for the linker. If this type of section appears in 276 the input file, the linker must copy it to the output file 277 without changing the vma or size. FIXME: Although this 278 was originally intended to be general, it really is COFF 279 specific (and the flag was renamed to indicate this). It 280 might be cleaner to have some more general mechanism to 281 allow the back end to control what the linker does with 282 sections. */ 283#define SEC_COFF_SHARED_LIBRARY 0x10000000 284 285 /* This section contains data which may be shared with other 286 executables or shared objects. This is for COFF only. */ 287#define SEC_COFF_SHARED 0x20000000 288 289 /* When a section with this flag is being linked, then if the size of 290 the input section is less than a page, it should not cross a page 291 boundary. If the size of the input section is one page or more, 292 it should be aligned on a page boundary. This is for TI 293 TMS320C54X only. */ 294#define SEC_TIC54X_BLOCK 0x40000000 295 296 /* Conditionally link this section; do not link if there are no 297 references found to any symbol in the section. This is for TI 298 TMS320C54X only. */ 299#define SEC_TIC54X_CLINK 0x80000000 300 301 /* End of section flags. */ 302 303 /* Some internal packed boolean fields. */ 304 305 /* See the vma field. */ 306 unsigned int user_set_vma : 1; 307 308 /* A mark flag used by some of the linker backends. */ 309 unsigned int linker_mark : 1; 310 311 /* Another mark flag used by some of the linker backends. Set for 312 output sections that have an input section. */ 313 unsigned int linker_has_input : 1; 314 315 /* Mark flags used by some linker backends for garbage collection. */ 316 unsigned int gc_mark : 1; 317 unsigned int gc_mark_from_eh : 1; 318 319 /* The following flags are used by the ELF linker. */ 320 321 /* Mark sections which have been allocated to segments. */ 322 unsigned int segment_mark : 1; 323 324 /* Type of sec_info information. */ 325 unsigned int sec_info_type:3; 326#define ELF_INFO_TYPE_NONE 0 327#define ELF_INFO_TYPE_STABS 1 328#define ELF_INFO_TYPE_MERGE 2 329#define ELF_INFO_TYPE_EH_FRAME 3 330#define ELF_INFO_TYPE_JUST_SYMS 4 331 332 /* Nonzero if this section uses RELA relocations, rather than REL. */ 333 unsigned int use_rela_p:1; 334 335 /* Bits used by various backends. The generic code doesn't touch 336 these fields. */ 337 338 /* Nonzero if this section has TLS related relocations. */ 339 unsigned int has_tls_reloc:1; 340 341 /* Nonzero if this section has a gp reloc. */ 342 unsigned int has_gp_reloc:1; 343 344 /* Nonzero if this section needs the relax finalize pass. */ 345 unsigned int need_finalize_relax:1; 346 347 /* Whether relocations have been processed. */ 348 unsigned int reloc_done : 1; 349 350 /* End of internal packed boolean fields. */ 351 352 /* The virtual memory address of the section - where it will be 353 at run time. The symbols are relocated against this. The 354 user_set_vma flag is maintained by bfd; if it's not set, the 355 backend can assign addresses (for example, in @code{a.out}, where 356 the default address for @code{.data} is dependent on the specific 357 target and various flags). */ 358 bfd_vma vma; 359 360 /* The load address of the section - where it would be in a 361 rom image; really only used for writing section header 362 information. */ 363 bfd_vma lma; 364 365 /* The size of the section in octets, as it will be output. 366 Contains a value even if the section has no contents (e.g., the 367 size of @code{.bss}). */ 368 bfd_size_type size; 369 370 /* For input sections, the original size on disk of the section, in 371 octets. This field is used by the linker relaxation code. It is 372 currently only set for sections where the linker relaxation scheme 373 doesn't cache altered section and reloc contents (stabs, eh_frame, 374 SEC_MERGE, some coff relaxing targets), and thus the original size 375 needs to be kept to read the section multiple times. 376 For output sections, rawsize holds the section size calculated on 377 a previous linker relaxation pass. */ 378 bfd_size_type rawsize; 379 380 /* If this section is going to be output, then this value is the 381 offset in *bytes* into the output section of the first byte in the 382 input section (byte ==> smallest addressable unit on the 383 target). In most cases, if this was going to start at the 384 100th octet (8-bit quantity) in the output section, this value 385 would be 100. However, if the target byte size is 16 bits 386 (bfd_octets_per_byte is "2"), this value would be 50. */ 387 bfd_vma output_offset; 388 389 /* The output section through which to map on output. */ 390 struct bfd_section *output_section; 391 392 /* The alignment requirement of the section, as an exponent of 2 - 393 e.g., 3 aligns to 2^3 (or 8). */ 394 unsigned int alignment_power; 395 396 /* If an input section, a pointer to a vector of relocation 397 records for the data in this section. */ 398 struct reloc_cache_entry *relocation; 399 400 /* If an output section, a pointer to a vector of pointers to 401 relocation records for the data in this section. */ 402 struct reloc_cache_entry **orelocation; 403 404 /* The number of relocation records in one of the above. */ 405 unsigned reloc_count; 406 407 /* Information below is back end specific - and not always used 408 or updated. */ 409 410 /* File position of section data. */ 411 file_ptr filepos; 412 413 /* File position of relocation info. */ 414 file_ptr rel_filepos; 415 416 /* File position of line data. */ 417 file_ptr line_filepos; 418 419 /* Pointer to data for applications. */ 420 void *userdata; 421 422 /* If the SEC_IN_MEMORY flag is set, this points to the actual 423 contents. */ 424 unsigned char *contents; 425 426 /* Attached line number information. */ 427 alent *lineno; 428 429 /* Number of line number records. */ 430 unsigned int lineno_count; 431 432 /* Entity size for merging purposes. */ 433 unsigned int entsize; 434 435 /* Points to the kept section if this section is a link-once section, 436 and is discarded. */ 437 struct bfd_section *kept_section; 438 439 /* When a section is being output, this value changes as more 440 linenumbers are written out. */ 441 file_ptr moving_line_filepos; 442 443 /* What the section number is in the target world. */ 444 int target_index; 445 446 void *used_by_bfd; 447 448 /* If this is a constructor section then here is a list of the 449 relocations created to relocate items within it. */ 450 struct relent_chain *constructor_chain; 451 452 /* The BFD which owns the section. */ 453 bfd *owner; 454 455 /* A symbol which points at this section only. */ 456 struct bfd_symbol *symbol; 457 struct bfd_symbol **symbol_ptr_ptr; 458 459 /* Early in the link process, map_head and map_tail are used to build 460 a list of input sections attached to an output section. Later, 461 output sections use these fields for a list of bfd_link_order 462 structs. */ 463 union @{ 464 struct bfd_link_order *link_order; 465 struct bfd_section *s; 466 @} map_head, map_tail; 467@} asection; 468 469/* These sections are global, and are managed by BFD. The application 470 and target back end are not permitted to change the values in 471 these sections. New code should use the section_ptr macros rather 472 than referring directly to the const sections. The const sections 473 may eventually vanish. */ 474#define BFD_ABS_SECTION_NAME "*ABS*" 475#define BFD_UND_SECTION_NAME "*UND*" 476#define BFD_COM_SECTION_NAME "*COM*" 477#define BFD_IND_SECTION_NAME "*IND*" 478 479/* The absolute section. */ 480extern asection bfd_abs_section; 481#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 482#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 483/* Pointer to the undefined section. */ 484extern asection bfd_und_section; 485#define bfd_und_section_ptr ((asection *) &bfd_und_section) 486#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 487/* Pointer to the common section. */ 488extern asection bfd_com_section; 489#define bfd_com_section_ptr ((asection *) &bfd_com_section) 490/* Pointer to the indirect section. */ 491extern asection bfd_ind_section; 492#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 493#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 494 495#define bfd_is_const_section(SEC) \ 496 ( ((SEC) == bfd_abs_section_ptr) \ 497 || ((SEC) == bfd_und_section_ptr) \ 498 || ((SEC) == bfd_com_section_ptr) \ 499 || ((SEC) == bfd_ind_section_ptr)) 500 501extern const struct bfd_symbol * const bfd_abs_symbol; 502extern const struct bfd_symbol * const bfd_com_symbol; 503extern const struct bfd_symbol * const bfd_und_symbol; 504extern const struct bfd_symbol * const bfd_ind_symbol; 505 506/* Macros to handle insertion and deletion of a bfd's sections. These 507 only handle the list pointers, ie. do not adjust section_count, 508 target_index etc. */ 509#define bfd_section_list_remove(ABFD, S) \ 510 do \ 511 @{ \ 512 asection *_s = S; \ 513 asection *_next = _s->next; \ 514 asection *_prev = _s->prev; \ 515 if (_prev) \ 516 _prev->next = _next; \ 517 else \ 518 (ABFD)->sections = _next; \ 519 if (_next) \ 520 _next->prev = _prev; \ 521 else \ 522 (ABFD)->section_last = _prev; \ 523 @} \ 524 while (0) 525#define bfd_section_list_append(ABFD, S) \ 526 do \ 527 @{ \ 528 asection *_s = S; \ 529 bfd *_abfd = ABFD; \ 530 _s->next = NULL; \ 531 if (_abfd->section_last) \ 532 @{ \ 533 _s->prev = _abfd->section_last; \ 534 _abfd->section_last->next = _s; \ 535 @} \ 536 else \ 537 @{ \ 538 _s->prev = NULL; \ 539 _abfd->sections = _s; \ 540 @} \ 541 _abfd->section_last = _s; \ 542 @} \ 543 while (0) 544#define bfd_section_list_prepend(ABFD, S) \ 545 do \ 546 @{ \ 547 asection *_s = S; \ 548 bfd *_abfd = ABFD; \ 549 _s->prev = NULL; \ 550 if (_abfd->sections) \ 551 @{ \ 552 _s->next = _abfd->sections; \ 553 _abfd->sections->prev = _s; \ 554 @} \ 555 else \ 556 @{ \ 557 _s->next = NULL; \ 558 _abfd->section_last = _s; \ 559 @} \ 560 _abfd->sections = _s; \ 561 @} \ 562 while (0) 563#define bfd_section_list_insert_after(ABFD, A, S) \ 564 do \ 565 @{ \ 566 asection *_a = A; \ 567 asection *_s = S; \ 568 asection *_next = _a->next; \ 569 _s->next = _next; \ 570 _s->prev = _a; \ 571 _a->next = _s; \ 572 if (_next) \ 573 _next->prev = _s; \ 574 else \ 575 (ABFD)->section_last = _s; \ 576 @} \ 577 while (0) 578#define bfd_section_list_insert_before(ABFD, B, S) \ 579 do \ 580 @{ \ 581 asection *_b = B; \ 582 asection *_s = S; \ 583 asection *_prev = _b->prev; \ 584 _s->prev = _prev; \ 585 _s->next = _b; \ 586 _b->prev = _s; \ 587 if (_prev) \ 588 _prev->next = _s; \ 589 else \ 590 (ABFD)->sections = _s; \ 591 @} \ 592 while (0) 593#define bfd_section_removed_from_list(ABFD, S) \ 594 ((S)->next == NULL ? (ABFD)->section_last != (S) : (S)->next->prev != (S)) 595 596#define BFD_FAKE_SECTION(SEC, FLAGS, SYM, SYM_PTR, NAME, IDX) \ 597 /* name, id, index, next, prev, flags, user_set_vma, */ \ 598 @{ NAME, IDX, 0, NULL, NULL, FLAGS, 0, \ 599 \ 600 /* linker_mark, linker_has_input, gc_mark, gc_mark_from_eh, */ \ 601 0, 0, 1, 0, \ 602 \ 603 /* segment_mark, sec_info_type, use_rela_p, has_tls_reloc, */ \ 604 0, 0, 0, 0, \ 605 \ 606 /* has_gp_reloc, need_finalize_relax, reloc_done, */ \ 607 0, 0, 0, \ 608 \ 609 /* vma, lma, size, rawsize */ \ 610 0, 0, 0, 0, \ 611 \ 612 /* output_offset, output_section, alignment_power, */ \ 613 0, (struct bfd_section *) &SEC, 0, \ 614 \ 615 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ 616 NULL, NULL, 0, 0, 0, \ 617 \ 618 /* line_filepos, userdata, contents, lineno, lineno_count, */ \ 619 0, NULL, NULL, NULL, 0, \ 620 \ 621 /* entsize, kept_section, moving_line_filepos, */ \ 622 0, NULL, 0, \ 623 \ 624 /* target_index, used_by_bfd, constructor_chain, owner, */ \ 625 0, NULL, NULL, NULL, \ 626 \ 627 /* symbol, */ \ 628 (struct bfd_symbol *) SYM, \ 629 \ 630 /* symbol_ptr_ptr, */ \ 631 (struct bfd_symbol **) SYM_PTR, \ 632 \ 633 /* map_head, map_tail */ \ 634 @{ NULL @}, @{ NULL @} \ 635 @} 636 637@end example 638 639@node section prototypes, , typedef asection, Sections 640@subsection Section prototypes 641These are the functions exported by the section handling part of BFD. 642 643@findex bfd_section_list_clear 644@subsubsection @code{bfd_section_list_clear} 645@strong{Synopsis} 646@example 647void bfd_section_list_clear (bfd *); 648@end example 649@strong{Description}@* 650Clears the section list, and also resets the section count and 651hash table entries. 652 653@findex bfd_get_section_by_name 654@subsubsection @code{bfd_get_section_by_name} 655@strong{Synopsis} 656@example 657asection *bfd_get_section_by_name (bfd *abfd, const char *name); 658@end example 659@strong{Description}@* 660Run through @var{abfd} and return the one of the 661@code{asection}s whose name matches @var{name}, otherwise @code{NULL}. 662@xref{Sections}, for more information. 663 664This should only be used in special cases; the normal way to process 665all sections of a given name is to use @code{bfd_map_over_sections} and 666@code{strcmp} on the name (or better yet, base it on the section flags 667or something else) for each section. 668 669@findex bfd_get_section_by_name_if 670@subsubsection @code{bfd_get_section_by_name_if} 671@strong{Synopsis} 672@example 673asection *bfd_get_section_by_name_if 674 (bfd *abfd, 675 const char *name, 676 bfd_boolean (*func) (bfd *abfd, asection *sect, void *obj), 677 void *obj); 678@end example 679@strong{Description}@* 680Call the provided function @var{func} for each section 681attached to the BFD @var{abfd} whose name matches @var{name}, 682passing @var{obj} as an argument. The function will be called 683as if by 684 685@example 686 func (abfd, the_section, obj); 687@end example 688 689It returns the first section for which @var{func} returns true, 690otherwise @code{NULL}. 691 692@findex bfd_get_unique_section_name 693@subsubsection @code{bfd_get_unique_section_name} 694@strong{Synopsis} 695@example 696char *bfd_get_unique_section_name 697 (bfd *abfd, const char *templat, int *count); 698@end example 699@strong{Description}@* 700Invent a section name that is unique in @var{abfd} by tacking 701a dot and a digit suffix onto the original @var{templat}. If 702@var{count} is non-NULL, then it specifies the first number 703tried as a suffix to generate a unique name. The value 704pointed to by @var{count} will be incremented in this case. 705 706@findex bfd_make_section_old_way 707@subsubsection @code{bfd_make_section_old_way} 708@strong{Synopsis} 709@example 710asection *bfd_make_section_old_way (bfd *abfd, const char *name); 711@end example 712@strong{Description}@* 713Create a new empty section called @var{name} 714and attach it to the end of the chain of sections for the 715BFD @var{abfd}. An attempt to create a section with a name which 716is already in use returns its pointer without changing the 717section chain. 718 719It has the funny name since this is the way it used to be 720before it was rewritten.... 721 722Possible errors are: 723@itemize @bullet 724 725@item 726@code{bfd_error_invalid_operation} - 727If output has already started for this BFD. 728@item 729@code{bfd_error_no_memory} - 730If memory allocation fails. 731@end itemize 732 733@findex bfd_make_section_anyway_with_flags 734@subsubsection @code{bfd_make_section_anyway_with_flags} 735@strong{Synopsis} 736@example 737asection *bfd_make_section_anyway_with_flags 738 (bfd *abfd, const char *name, flagword flags); 739@end example 740@strong{Description}@* 741Create a new empty section called @var{name} and attach it to the end of 742the chain of sections for @var{abfd}. Create a new section even if there 743is already a section with that name. Also set the attributes of the 744new section to the value @var{flags}. 745 746Return @code{NULL} and set @code{bfd_error} on error; possible errors are: 747@itemize @bullet 748 749@item 750@code{bfd_error_invalid_operation} - If output has already started for @var{abfd}. 751@item 752@code{bfd_error_no_memory} - If memory allocation fails. 753@end itemize 754 755@findex bfd_make_section_anyway 756@subsubsection @code{bfd_make_section_anyway} 757@strong{Synopsis} 758@example 759asection *bfd_make_section_anyway (bfd *abfd, const char *name); 760@end example 761@strong{Description}@* 762Create a new empty section called @var{name} and attach it to the end of 763the chain of sections for @var{abfd}. Create a new section even if there 764is already a section with that name. 765 766Return @code{NULL} and set @code{bfd_error} on error; possible errors are: 767@itemize @bullet 768 769@item 770@code{bfd_error_invalid_operation} - If output has already started for @var{abfd}. 771@item 772@code{bfd_error_no_memory} - If memory allocation fails. 773@end itemize 774 775@findex bfd_make_section_with_flags 776@subsubsection @code{bfd_make_section_with_flags} 777@strong{Synopsis} 778@example 779asection *bfd_make_section_with_flags 780 (bfd *, const char *name, flagword flags); 781@end example 782@strong{Description}@* 783Like @code{bfd_make_section_anyway}, but return @code{NULL} (without calling 784bfd_set_error ()) without changing the section chain if there is already a 785section named @var{name}. Also set the attributes of the new section to 786the value @var{flags}. If there is an error, return @code{NULL} and set 787@code{bfd_error}. 788 789@findex bfd_make_section 790@subsubsection @code{bfd_make_section} 791@strong{Synopsis} 792@example 793asection *bfd_make_section (bfd *, const char *name); 794@end example 795@strong{Description}@* 796Like @code{bfd_make_section_anyway}, but return @code{NULL} (without calling 797bfd_set_error ()) without changing the section chain if there is already a 798section named @var{name}. If there is an error, return @code{NULL} and set 799@code{bfd_error}. 800 801@findex bfd_set_section_flags 802@subsubsection @code{bfd_set_section_flags} 803@strong{Synopsis} 804@example 805bfd_boolean bfd_set_section_flags 806 (bfd *abfd, asection *sec, flagword flags); 807@end example 808@strong{Description}@* 809Set the attributes of the section @var{sec} in the BFD 810@var{abfd} to the value @var{flags}. Return @code{TRUE} on success, 811@code{FALSE} on error. Possible error returns are: 812 813@itemize @bullet 814 815@item 816@code{bfd_error_invalid_operation} - 817The section cannot have one or more of the attributes 818requested. For example, a .bss section in @code{a.out} may not 819have the @code{SEC_HAS_CONTENTS} field set. 820@end itemize 821 822@findex bfd_map_over_sections 823@subsubsection @code{bfd_map_over_sections} 824@strong{Synopsis} 825@example 826void bfd_map_over_sections 827 (bfd *abfd, 828 void (*func) (bfd *abfd, asection *sect, void *obj), 829 void *obj); 830@end example 831@strong{Description}@* 832Call the provided function @var{func} for each section 833attached to the BFD @var{abfd}, passing @var{obj} as an 834argument. The function will be called as if by 835 836@example 837 func (abfd, the_section, obj); 838@end example 839 840This is the preferred method for iterating over sections; an 841alternative would be to use a loop: 842 843@example 844 section *p; 845 for (p = abfd->sections; p != NULL; p = p->next) 846 func (abfd, p, ...) 847@end example 848 849@findex bfd_sections_find_if 850@subsubsection @code{bfd_sections_find_if} 851@strong{Synopsis} 852@example 853asection *bfd_sections_find_if 854 (bfd *abfd, 855 bfd_boolean (*operation) (bfd *abfd, asection *sect, void *obj), 856 void *obj); 857@end example 858@strong{Description}@* 859Call the provided function @var{operation} for each section 860attached to the BFD @var{abfd}, passing @var{obj} as an 861argument. The function will be called as if by 862 863@example 864 operation (abfd, the_section, obj); 865@end example 866 867It returns the first section for which @var{operation} returns true. 868 869@findex bfd_set_section_size 870@subsubsection @code{bfd_set_section_size} 871@strong{Synopsis} 872@example 873bfd_boolean bfd_set_section_size 874 (bfd *abfd, asection *sec, bfd_size_type val); 875@end example 876@strong{Description}@* 877Set @var{sec} to the size @var{val}. If the operation is 878ok, then @code{TRUE} is returned, else @code{FALSE}. 879 880Possible error returns: 881@itemize @bullet 882 883@item 884@code{bfd_error_invalid_operation} - 885Writing has started to the BFD, so setting the size is invalid. 886@end itemize 887 888@findex bfd_set_section_contents 889@subsubsection @code{bfd_set_section_contents} 890@strong{Synopsis} 891@example 892bfd_boolean bfd_set_section_contents 893 (bfd *abfd, asection *section, const void *data, 894 file_ptr offset, bfd_size_type count); 895@end example 896@strong{Description}@* 897Sets the contents of the section @var{section} in BFD 898@var{abfd} to the data starting in memory at @var{data}. The 899data is written to the output section starting at offset 900@var{offset} for @var{count} octets. 901 902Normally @code{TRUE} is returned, else @code{FALSE}. Possible error 903returns are: 904@itemize @bullet 905 906@item 907@code{bfd_error_no_contents} - 908The output section does not have the @code{SEC_HAS_CONTENTS} 909attribute, so nothing can be written to it. 910@item 911and some more too 912@end itemize 913This routine is front end to the back end function 914@code{_bfd_set_section_contents}. 915 916@findex bfd_get_section_contents 917@subsubsection @code{bfd_get_section_contents} 918@strong{Synopsis} 919@example 920bfd_boolean bfd_get_section_contents 921 (bfd *abfd, asection *section, void *location, file_ptr offset, 922 bfd_size_type count); 923@end example 924@strong{Description}@* 925Read data from @var{section} in BFD @var{abfd} 926into memory starting at @var{location}. The data is read at an 927offset of @var{offset} from the start of the input section, 928and is read for @var{count} bytes. 929 930If the contents of a constructor with the @code{SEC_CONSTRUCTOR} 931flag set are requested or if the section does not have the 932@code{SEC_HAS_CONTENTS} flag set, then the @var{location} is filled 933with zeroes. If no errors occur, @code{TRUE} is returned, else 934@code{FALSE}. 935 936@findex bfd_malloc_and_get_section 937@subsubsection @code{bfd_malloc_and_get_section} 938@strong{Synopsis} 939@example 940bfd_boolean bfd_malloc_and_get_section 941 (bfd *abfd, asection *section, bfd_byte **buf); 942@end example 943@strong{Description}@* 944Read all data from @var{section} in BFD @var{abfd} 945into a buffer, *@var{buf}, malloc'd by this function. 946 947@findex bfd_copy_private_section_data 948@subsubsection @code{bfd_copy_private_section_data} 949@strong{Synopsis} 950@example 951bfd_boolean bfd_copy_private_section_data 952 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec); 953@end example 954@strong{Description}@* 955Copy private section information from @var{isec} in the BFD 956@var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 957Return @code{TRUE} on success, @code{FALSE} on error. Possible error 958returns are: 959 960@itemize @bullet 961 962@item 963@code{bfd_error_no_memory} - 964Not enough memory exists to create private data for @var{osec}. 965@end itemize 966@example 967#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 968 BFD_SEND (obfd, _bfd_copy_private_section_data, \ 969 (ibfd, isection, obfd, osection)) 970@end example 971 972@findex bfd_generic_is_group_section 973@subsubsection @code{bfd_generic_is_group_section} 974@strong{Synopsis} 975@example 976bfd_boolean bfd_generic_is_group_section (bfd *, const asection *sec); 977@end example 978@strong{Description}@* 979Returns TRUE if @var{sec} is a member of a group. 980 981@findex bfd_generic_discard_group 982@subsubsection @code{bfd_generic_discard_group} 983@strong{Synopsis} 984@example 985bfd_boolean bfd_generic_discard_group (bfd *abfd, asection *group); 986@end example 987@strong{Description}@* 988Remove all members of @var{group} from the output. 989 990