1 /* Object file "section" support for the BFD library. 2 Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 97, 98, 1999 3 Free Software Foundation, Inc. 4 Written by Cygnus Support. 5 6 This file is part of BFD, the Binary File Descriptor library. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 2 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program; if not, write to the Free Software 20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 21 22 /* 23 SECTION 24 Sections 25 26 The raw data contained within a BFD is maintained through the 27 section abstraction. A single BFD may have any number of 28 sections. It keeps hold of them by pointing to the first; 29 each one points to the next in the list. 30 31 Sections are supported in BFD in <<section.c>>. 32 33 @menu 34 @* Section Input:: 35 @* Section Output:: 36 @* typedef asection:: 37 @* section prototypes:: 38 @end menu 39 40 INODE 41 Section Input, Section Output, Sections, Sections 42 SUBSECTION 43 Section input 44 45 When a BFD is opened for reading, the section structures are 46 created and attached to the BFD. 47 48 Each section has a name which describes the section in the 49 outside world---for example, <<a.out>> would contain at least 50 three sections, called <<.text>>, <<.data>> and <<.bss>>. 51 52 Names need not be unique; for example a COFF file may have several 53 sections named <<.data>>. 54 55 Sometimes a BFD will contain more than the ``natural'' number of 56 sections. A back end may attach other sections containing 57 constructor data, or an application may add a section (using 58 <<bfd_make_section>>) to the sections attached to an already open 59 BFD. For example, the linker creates an extra section 60 <<COMMON>> for each input file's BFD to hold information about 61 common storage. 62 63 The raw data is not necessarily read in when 64 the section descriptor is created. Some targets may leave the 65 data in place until a <<bfd_get_section_contents>> call is 66 made. Other back ends may read in all the data at once. For 67 example, an S-record file has to be read once to determine the 68 size of the data. An IEEE-695 file doesn't contain raw data in 69 sections, but data and relocation expressions intermixed, so 70 the data area has to be parsed to get out the data and 71 relocations. 72 73 INODE 74 Section Output, typedef asection, Section Input, Sections 75 76 SUBSECTION 77 Section output 78 79 To write a new object style BFD, the various sections to be 80 written have to be created. They are attached to the BFD in 81 the same way as input sections; data is written to the 82 sections using <<bfd_set_section_contents>>. 83 84 Any program that creates or combines sections (e.g., the assembler 85 and linker) must use the <<asection>> fields <<output_section>> and 86 <<output_offset>> to indicate the file sections to which each 87 section must be written. (If the section is being created from 88 scratch, <<output_section>> should probably point to the section 89 itself and <<output_offset>> should probably be zero.) 90 91 The data to be written comes from input sections attached 92 (via <<output_section>> pointers) to 93 the output sections. The output section structure can be 94 considered a filter for the input section: the output section 95 determines the vma of the output data and the name, but the 96 input section determines the offset into the output section of 97 the data to be written. 98 99 E.g., to create a section "O", starting at 0x100, 0x123 long, 100 containing two subsections, "A" at offset 0x0 (i.e., at vma 101 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>> 102 structures would look like: 103 104 | section name "A" 105 | output_offset 0x00 106 | size 0x20 107 | output_section -----------> section name "O" 108 | | vma 0x100 109 | section name "B" | size 0x123 110 | output_offset 0x20 | 111 | size 0x103 | 112 | output_section --------| 113 114 115 SUBSECTION 116 Link orders 117 118 The data within a section is stored in a @dfn{link_order}. 119 These are much like the fixups in <<gas>>. The link_order 120 abstraction allows a section to grow and shrink within itself. 121 122 A link_order knows how big it is, and which is the next 123 link_order and where the raw data for it is; it also points to 124 a list of relocations which apply to it. 125 126 The link_order is used by the linker to perform relaxing on 127 final code. The compiler creates code which is as big as 128 necessary to make it work without relaxing, and the user can 129 select whether to relax. Sometimes relaxing takes a lot of 130 time. The linker runs around the relocations to see if any 131 are attached to data which can be shrunk, if so it does it on 132 a link_order by link_order basis. 133 134 */ 135 136 137 #include "bfd.h" 138 #include "sysdep.h" 139 #include "libbfd.h" 140 #include "bfdlink.h" 141 142 /* 143 DOCDD 144 INODE 145 typedef asection, section prototypes, Section Output, Sections 146 SUBSECTION 147 typedef asection 148 149 Here is the section structure: 150 151 CODE_FRAGMENT 152 . 153 . {* This structure is used for a comdat section, as in PE. A comdat 154 . section is associated with a particular symbol. When the linker 155 . sees a comdat section, it keeps only one of the sections with a 156 . given name and associated with a given symbol. *} 157 . 158 .struct bfd_comdat_info 159 .{ 160 . {* The name of the symbol associated with a comdat section. *} 161 . const char *name; 162 . 163 . {* The local symbol table index of the symbol associated with a 164 . comdat section. This is only meaningful to the object file format 165 . specific code; it is not an index into the list returned by 166 . bfd_canonicalize_symtab. *} 167 . long symbol; 168 . 169 . {* If this section is being discarded, the linker uses this field 170 . to point to the input section which is being kept. *} 171 . struct sec *sec; 172 .}; 173 . 174 .typedef struct sec 175 .{ 176 . {* The name of the section; the name isn't a copy, the pointer is 177 . the same as that passed to bfd_make_section. *} 178 . 179 . CONST char *name; 180 . 181 . {* Which section is it; 0..nth. *} 182 . 183 . int index; 184 . 185 . {* The next section in the list belonging to the BFD, or NULL. *} 186 . 187 . struct sec *next; 188 . 189 . {* The field flags contains attributes of the section. Some 190 . flags are read in from the object file, and some are 191 . synthesized from other information. *} 192 . 193 . flagword flags; 194 . 195 .#define SEC_NO_FLAGS 0x000 196 . 197 . {* Tells the OS to allocate space for this section when loading. 198 . This is clear for a section containing debug information 199 . only. *} 200 .#define SEC_ALLOC 0x001 201 . 202 . {* Tells the OS to load the section from the file when loading. 203 . This is clear for a .bss section. *} 204 .#define SEC_LOAD 0x002 205 . 206 . {* The section contains data still to be relocated, so there is 207 . some relocation information too. *} 208 .#define SEC_RELOC 0x004 209 . 210 .#if 0 {* Obsolete ? *} 211 .#define SEC_BALIGN 0x008 212 .#endif 213 . 214 . {* A signal to the OS that the section contains read only 215 . data. *} 216 .#define SEC_READONLY 0x010 217 . 218 . {* The section contains code only. *} 219 .#define SEC_CODE 0x020 220 . 221 . {* The section contains data only. *} 222 .#define SEC_DATA 0x040 223 . 224 . {* The section will reside in ROM. *} 225 .#define SEC_ROM 0x080 226 . 227 . {* The section contains constructor information. This section 228 . type is used by the linker to create lists of constructors and 229 . destructors used by <<g++>>. When a back end sees a symbol 230 . which should be used in a constructor list, it creates a new 231 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches 232 . the symbol to it, and builds a relocation. To build the lists 233 . of constructors, all the linker has to do is catenate all the 234 . sections called <<__CTOR_LIST__>> and relocate the data 235 . contained within - exactly the operations it would peform on 236 . standard data. *} 237 .#define SEC_CONSTRUCTOR 0x100 238 . 239 . {* The section is a constructor, and should be placed at the 240 . end of the text, data, or bss section(?). *} 241 .#define SEC_CONSTRUCTOR_TEXT 0x1100 242 .#define SEC_CONSTRUCTOR_DATA 0x2100 243 .#define SEC_CONSTRUCTOR_BSS 0x3100 244 . 245 . {* The section has contents - a data section could be 246 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be 247 . <<SEC_HAS_CONTENTS>> *} 248 .#define SEC_HAS_CONTENTS 0x200 249 . 250 . {* An instruction to the linker to not output the section 251 . even if it has information which would normally be written. *} 252 .#define SEC_NEVER_LOAD 0x400 253 . 254 . {* The section is a COFF shared library section. This flag is 255 . only for the linker. If this type of section appears in 256 . the input file, the linker must copy it to the output file 257 . without changing the vma or size. FIXME: Although this 258 . was originally intended to be general, it really is COFF 259 . specific (and the flag was renamed to indicate this). It 260 . might be cleaner to have some more general mechanism to 261 . allow the back end to control what the linker does with 262 . sections. *} 263 .#define SEC_COFF_SHARED_LIBRARY 0x800 264 . 265 . {* The section contains common symbols (symbols may be defined 266 . multiple times, the value of a symbol is the amount of 267 . space it requires, and the largest symbol value is the one 268 . used). Most targets have exactly one of these (which we 269 . translate to bfd_com_section_ptr), but ECOFF has two. *} 270 .#define SEC_IS_COMMON 0x8000 271 . 272 . {* The section contains only debugging information. For 273 . example, this is set for ELF .debug and .stab sections. 274 . strip tests this flag to see if a section can be 275 . discarded. *} 276 .#define SEC_DEBUGGING 0x10000 277 . 278 . {* The contents of this section are held in memory pointed to 279 . by the contents field. This is checked by 280 . bfd_get_section_contents, and the data is retrieved from 281 . memory if appropriate. *} 282 .#define SEC_IN_MEMORY 0x20000 283 . 284 . {* The contents of this section are to be excluded by the 285 . linker for executable and shared objects unless those 286 . objects are to be further relocated. *} 287 .#define SEC_EXCLUDE 0x40000 288 . 289 . {* The contents of this section are to be sorted by the 290 . based on the address specified in the associated symbol 291 . table. *} 292 .#define SEC_SORT_ENTRIES 0x80000 293 . 294 . {* When linking, duplicate sections of the same name should be 295 . discarded, rather than being combined into a single section as 296 . is usually done. This is similar to how common symbols are 297 . handled. See SEC_LINK_DUPLICATES below. *} 298 .#define SEC_LINK_ONCE 0x100000 299 . 300 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker 301 . should handle duplicate sections. *} 302 .#define SEC_LINK_DUPLICATES 0x600000 303 . 304 . {* This value for SEC_LINK_DUPLICATES means that duplicate 305 . sections with the same name should simply be discarded. *} 306 .#define SEC_LINK_DUPLICATES_DISCARD 0x0 307 . 308 . {* This value for SEC_LINK_DUPLICATES means that the linker 309 . should warn if there are any duplicate sections, although 310 . it should still only link one copy. *} 311 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000 312 . 313 . {* This value for SEC_LINK_DUPLICATES means that the linker 314 . should warn if any duplicate sections are a different size. *} 315 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000 316 . 317 . {* This value for SEC_LINK_DUPLICATES means that the linker 318 . should warn if any duplicate sections contain different 319 . contents. *} 320 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000 321 . 322 . {* This section was created by the linker as part of dynamic 323 . relocation or other arcane processing. It is skipped when 324 . going through the first-pass output, trusting that someone 325 . else up the line will take care of it later. *} 326 .#define SEC_LINKER_CREATED 0x800000 327 . 328 . {* This section should not be subject to garbage collection. *} 329 .#define SEC_KEEP 0x1000000 330 . 331 . {* This section contains "short" data, and should be placed 332 . "near" the GP. *} 333 .#define SEC_SMALL_DATA 0x2000000 334 . 335 . {* This section contains data which may be shared with other 336 . executables or shared objects. *} 337 .#define SEC_SHARED 0x4000000 338 . 339 . {* End of section flags. *} 340 . 341 . {* Some internal packed boolean fields. *} 342 . 343 . {* See the vma field. *} 344 . unsigned int user_set_vma : 1; 345 . 346 . {* Whether relocations have been processed. *} 347 . unsigned int reloc_done : 1; 348 . 349 . {* A mark flag used by some of the linker backends. *} 350 . unsigned int linker_mark : 1; 351 . 352 . {* A mark flag used by some linker backends for garbage collection. *} 353 . unsigned int gc_mark : 1; 354 . 355 . {* End of internal packed boolean fields. *} 356 . 357 . {* The virtual memory address of the section - where it will be 358 . at run time. The symbols are relocated against this. The 359 . user_set_vma flag is maintained by bfd; if it's not set, the 360 . backend can assign addresses (for example, in <<a.out>>, where 361 . the default address for <<.data>> is dependent on the specific 362 . target and various flags). *} 363 . 364 . bfd_vma vma; 365 . 366 . {* The load address of the section - where it would be in a 367 . rom image; really only used for writing section header 368 . information. *} 369 . 370 . bfd_vma lma; 371 . 372 . {* The size of the section in octets, as it will be output. 373 . Contains a value even if the section has no contents (e.g., the 374 . size of <<.bss>>). This will be filled in after relocation. *} 375 . 376 . bfd_size_type _cooked_size; 377 . 378 . {* The original size on disk of the section, in octets. Normally this 379 . value is the same as the size, but if some relaxing has 380 . been done, then this value will be bigger. *} 381 . 382 . bfd_size_type _raw_size; 383 . 384 . {* If this section is going to be output, then this value is the 385 . offset in *bytes* into the output section of the first byte in the 386 . input section (byte ==> smallest addressable unit on the 387 . target). In most cases, if this was going to start at the 388 . 100th octet (8-bit quantity) in the output section, this value 389 . would be 100. However, if the target byte size is 16 bits 390 . (bfd_octets_per_byte is "2"), this value would be 50. *} 391 . 392 . bfd_vma output_offset; 393 . 394 . {* The output section through which to map on output. *} 395 . 396 . struct sec *output_section; 397 . 398 . {* The alignment requirement of the section, as an exponent of 2 - 399 . e.g., 3 aligns to 2^3 (or 8). *} 400 . 401 . unsigned int alignment_power; 402 . 403 . {* If an input section, a pointer to a vector of relocation 404 . records for the data in this section. *} 405 . 406 . struct reloc_cache_entry *relocation; 407 . 408 . {* If an output section, a pointer to a vector of pointers to 409 . relocation records for the data in this section. *} 410 . 411 . struct reloc_cache_entry **orelocation; 412 . 413 . {* The number of relocation records in one of the above *} 414 . 415 . unsigned reloc_count; 416 . 417 . {* Information below is back end specific - and not always used 418 . or updated. *} 419 . 420 . {* File position of section data *} 421 . 422 . file_ptr filepos; 423 . 424 . {* File position of relocation info *} 425 . 426 . file_ptr rel_filepos; 427 . 428 . {* File position of line data *} 429 . 430 . file_ptr line_filepos; 431 . 432 . {* Pointer to data for applications *} 433 . 434 . PTR userdata; 435 . 436 . {* If the SEC_IN_MEMORY flag is set, this points to the actual 437 . contents. *} 438 . unsigned char *contents; 439 . 440 . {* Attached line number information *} 441 . 442 . alent *lineno; 443 . 444 . {* Number of line number records *} 445 . 446 . unsigned int lineno_count; 447 . 448 . {* Optional information about a COMDAT entry; NULL if not COMDAT *} 449 . 450 . struct bfd_comdat_info *comdat; 451 . 452 . {* When a section is being output, this value changes as more 453 . linenumbers are written out *} 454 . 455 . file_ptr moving_line_filepos; 456 . 457 . {* What the section number is in the target world *} 458 . 459 . int target_index; 460 . 461 . PTR used_by_bfd; 462 . 463 . {* If this is a constructor section then here is a list of the 464 . relocations created to relocate items within it. *} 465 . 466 . struct relent_chain *constructor_chain; 467 . 468 . {* The BFD which owns the section. *} 469 . 470 . bfd *owner; 471 . 472 . {* A symbol which points at this section only *} 473 . struct symbol_cache_entry *symbol; 474 . struct symbol_cache_entry **symbol_ptr_ptr; 475 . 476 . struct bfd_link_order *link_order_head; 477 . struct bfd_link_order *link_order_tail; 478 .} asection ; 479 . 480 . {* These sections are global, and are managed by BFD. The application 481 . and target back end are not permitted to change the values in 482 . these sections. New code should use the section_ptr macros rather 483 . than referring directly to the const sections. The const sections 484 . may eventually vanish. *} 485 .#define BFD_ABS_SECTION_NAME "*ABS*" 486 .#define BFD_UND_SECTION_NAME "*UND*" 487 .#define BFD_COM_SECTION_NAME "*COM*" 488 .#define BFD_IND_SECTION_NAME "*IND*" 489 . 490 . {* the absolute section *} 491 .extern const asection bfd_abs_section; 492 .#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 493 .#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 494 . {* Pointer to the undefined section *} 495 .extern const asection bfd_und_section; 496 .#define bfd_und_section_ptr ((asection *) &bfd_und_section) 497 .#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 498 . {* Pointer to the common section *} 499 .extern const asection bfd_com_section; 500 .#define bfd_com_section_ptr ((asection *) &bfd_com_section) 501 . {* Pointer to the indirect section *} 502 .extern const asection bfd_ind_section; 503 .#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 504 .#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 505 . 506 .extern const struct symbol_cache_entry * const bfd_abs_symbol; 507 .extern const struct symbol_cache_entry * const bfd_com_symbol; 508 .extern const struct symbol_cache_entry * const bfd_und_symbol; 509 .extern const struct symbol_cache_entry * const bfd_ind_symbol; 510 .#define bfd_get_section_size_before_reloc(section) \ 511 . ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \ 512 . : (section)->_raw_size) 513 .#define bfd_get_section_size_after_reloc(section) \ 514 . ((section)->reloc_done ? (section)->_cooked_size \ 515 . : (abort (), (bfd_size_type) 1)) 516 */ 517 518 /* We use a macro to initialize the static asymbol structures because 519 traditional C does not permit us to initialize a union member while 520 gcc warns if we don't initialize it. */ 521 /* the_bfd, name, value, attr, section [, udata] */ 522 #ifdef __STDC__ 523 #define GLOBAL_SYM_INIT(NAME, SECTION) \ 524 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }} 525 #else 526 #define GLOBAL_SYM_INIT(NAME, SECTION) \ 527 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION } 528 #endif 529 530 /* These symbols are global, not specific to any BFD. Therefore, anything 531 that tries to change them is broken, and should be repaired. */ 532 533 static const asymbol global_syms[] = 534 { 535 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section), 536 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section), 537 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section), 538 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section) 539 }; 540 541 #define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ 542 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \ 543 const asection SEC = \ 544 /* name, index, next, flags, set_vma, reloc_done, linker_mark, gc_mark */ \ 545 { NAME, 0, 0, FLAGS, 0, 0, 0, 0, \ 546 \ 547 /* vma, lma, _cooked_size, _raw_size, output_offset, output_section, */ \ 548 0, 0, 0, 0, 0, (struct sec *) &SEC, \ 549 \ 550 /* alig..., reloc..., orel..., reloc_count, filepos, rel_..., line_... */ \ 551 0, 0, 0, 0, 0, 0, 0, \ 552 \ 553 /* userdata, contents, lineno, lineno_count */ \ 554 0, 0, 0, 0, \ 555 \ 556 /* comdat_info, moving_line_filepos, target_index, used_by_bfd, */ \ 557 NULL, 0, 0, 0, \ 558 \ 559 /* cons..., owner, symbol */ \ 560 0, 0, (struct symbol_cache_entry *) &global_syms[IDX], \ 561 \ 562 /* symbol_ptr_ptr, link_order_head, ..._tail */ \ 563 (struct symbol_cache_entry **) &SYM, 0, 0 \ 564 } 565 566 STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, 567 BFD_COM_SECTION_NAME, 0); 568 STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1); 569 STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2); 570 STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3); 571 #undef STD_SECTION 572 573 /* 574 DOCDD 575 INODE 576 section prototypes, , typedef asection, Sections 577 SUBSECTION 578 Section prototypes 579 580 These are the functions exported by the section handling part of BFD. 581 */ 582 583 /* 584 FUNCTION 585 bfd_get_section_by_name 586 587 SYNOPSIS 588 asection *bfd_get_section_by_name(bfd *abfd, CONST char *name); 589 590 DESCRIPTION 591 Run through @var{abfd} and return the one of the 592 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>. 593 @xref{Sections}, for more information. 594 595 This should only be used in special cases; the normal way to process 596 all sections of a given name is to use <<bfd_map_over_sections>> and 597 <<strcmp>> on the name (or better yet, base it on the section flags 598 or something else) for each section. 599 */ 600 601 asection * 602 bfd_get_section_by_name (abfd, name) 603 bfd *abfd; 604 CONST char *name; 605 { 606 asection *sect; 607 608 for (sect = abfd->sections; sect != NULL; sect = sect->next) 609 if (!strcmp (sect->name, name)) 610 return sect; 611 return NULL; 612 } 613 614 615 /* 616 FUNCTION 617 bfd_make_section_old_way 618 619 SYNOPSIS 620 asection *bfd_make_section_old_way(bfd *abfd, CONST char *name); 621 622 DESCRIPTION 623 Create a new empty section called @var{name} 624 and attach it to the end of the chain of sections for the 625 BFD @var{abfd}. An attempt to create a section with a name which 626 is already in use returns its pointer without changing the 627 section chain. 628 629 It has the funny name since this is the way it used to be 630 before it was rewritten.... 631 632 Possible errors are: 633 o <<bfd_error_invalid_operation>> - 634 If output has already started for this BFD. 635 o <<bfd_error_no_memory>> - 636 If memory allocation fails. 637 638 */ 639 640 641 asection * 642 bfd_make_section_old_way (abfd, name) 643 bfd *abfd; 644 CONST char *name; 645 { 646 asection *sec = bfd_get_section_by_name (abfd, name); 647 if (sec == (asection *) NULL) 648 { 649 sec = bfd_make_section (abfd, name); 650 } 651 return sec; 652 } 653 654 /* 655 FUNCTION 656 bfd_make_section_anyway 657 658 SYNOPSIS 659 asection *bfd_make_section_anyway(bfd *abfd, CONST char *name); 660 661 DESCRIPTION 662 Create a new empty section called @var{name} and attach it to the end of 663 the chain of sections for @var{abfd}. Create a new section even if there 664 is already a section with that name. 665 666 Return <<NULL>> and set <<bfd_error>> on error; possible errors are: 667 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}. 668 o <<bfd_error_no_memory>> - If memory allocation fails. 669 */ 670 671 sec_ptr 672 bfd_make_section_anyway (abfd, name) 673 bfd *abfd; 674 CONST char *name; 675 { 676 asection *newsect; 677 asection **prev = &abfd->sections; 678 asection *sect = abfd->sections; 679 680 if (abfd->output_has_begun) 681 { 682 bfd_set_error (bfd_error_invalid_operation); 683 return NULL; 684 } 685 686 while (sect) 687 { 688 prev = §->next; 689 sect = sect->next; 690 } 691 692 newsect = (asection *) bfd_zalloc (abfd, sizeof (asection)); 693 if (newsect == NULL) 694 return NULL; 695 696 newsect->name = name; 697 newsect->index = abfd->section_count++; 698 newsect->flags = SEC_NO_FLAGS; 699 700 newsect->userdata = NULL; 701 newsect->contents = NULL; 702 newsect->next = (asection *) NULL; 703 newsect->relocation = (arelent *) NULL; 704 newsect->reloc_count = 0; 705 newsect->line_filepos = 0; 706 newsect->owner = abfd; 707 newsect->comdat = NULL; 708 709 /* Create a symbol whos only job is to point to this section. This is 710 useful for things like relocs which are relative to the base of a 711 section. */ 712 newsect->symbol = bfd_make_empty_symbol (abfd); 713 if (newsect->symbol == NULL) 714 return NULL; 715 newsect->symbol->name = name; 716 newsect->symbol->value = 0; 717 newsect->symbol->section = newsect; 718 newsect->symbol->flags = BSF_SECTION_SYM; 719 720 newsect->symbol_ptr_ptr = &newsect->symbol; 721 722 if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) 723 { 724 free (newsect); 725 return NULL; 726 } 727 728 *prev = newsect; 729 return newsect; 730 } 731 732 /* 733 FUNCTION 734 bfd_make_section 735 736 SYNOPSIS 737 asection *bfd_make_section(bfd *, CONST char *name); 738 739 DESCRIPTION 740 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling 741 bfd_set_error ()) without changing the section chain if there is already a 742 section named @var{name}. If there is an error, return <<NULL>> and set 743 <<bfd_error>>. 744 */ 745 746 asection * 747 bfd_make_section (abfd, name) 748 bfd *abfd; 749 CONST char *name; 750 { 751 asection *sect = abfd->sections; 752 753 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0) 754 { 755 return bfd_abs_section_ptr; 756 } 757 if (strcmp (name, BFD_COM_SECTION_NAME) == 0) 758 { 759 return bfd_com_section_ptr; 760 } 761 if (strcmp (name, BFD_UND_SECTION_NAME) == 0) 762 { 763 return bfd_und_section_ptr; 764 } 765 766 if (strcmp (name, BFD_IND_SECTION_NAME) == 0) 767 { 768 return bfd_ind_section_ptr; 769 } 770 771 while (sect) 772 { 773 if (!strcmp (sect->name, name)) 774 return NULL; 775 sect = sect->next; 776 } 777 778 /* The name is not already used; go ahead and make a new section. */ 779 return bfd_make_section_anyway (abfd, name); 780 } 781 782 783 /* 784 FUNCTION 785 bfd_set_section_flags 786 787 SYNOPSIS 788 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags); 789 790 DESCRIPTION 791 Set the attributes of the section @var{sec} in the BFD 792 @var{abfd} to the value @var{flags}. Return <<true>> on success, 793 <<false>> on error. Possible error returns are: 794 795 o <<bfd_error_invalid_operation>> - 796 The section cannot have one or more of the attributes 797 requested. For example, a .bss section in <<a.out>> may not 798 have the <<SEC_HAS_CONTENTS>> field set. 799 800 */ 801 802 /*ARGSUSED*/ 803 boolean 804 bfd_set_section_flags (abfd, section, flags) 805 bfd *abfd ATTRIBUTE_UNUSED; 806 sec_ptr section; 807 flagword flags; 808 { 809 #if 0 810 /* If you try to copy a text section from an input file (where it 811 has the SEC_CODE flag set) to an output file, this loses big if 812 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE 813 set - which it doesn't, at least not for a.out. FIXME */ 814 815 if ((flags & bfd_applicable_section_flags (abfd)) != flags) 816 { 817 bfd_set_error (bfd_error_invalid_operation); 818 return false; 819 } 820 #endif 821 822 section->flags = flags; 823 return true; 824 } 825 826 827 /* 828 FUNCTION 829 bfd_map_over_sections 830 831 SYNOPSIS 832 void bfd_map_over_sections(bfd *abfd, 833 void (*func)(bfd *abfd, 834 asection *sect, 835 PTR obj), 836 PTR obj); 837 838 DESCRIPTION 839 Call the provided function @var{func} for each section 840 attached to the BFD @var{abfd}, passing @var{obj} as an 841 argument. The function will be called as if by 842 843 | func(abfd, the_section, obj); 844 845 This is the prefered method for iterating over sections; an 846 alternative would be to use a loop: 847 848 | section *p; 849 | for (p = abfd->sections; p != NULL; p = p->next) 850 | func(abfd, p, ...) 851 852 853 */ 854 855 /*VARARGS2*/ 856 void 857 bfd_map_over_sections (abfd, operation, user_storage) 858 bfd *abfd; 859 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj)); 860 PTR user_storage; 861 { 862 asection *sect; 863 unsigned int i = 0; 864 865 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next) 866 (*operation) (abfd, sect, user_storage); 867 868 if (i != abfd->section_count) /* Debugging */ 869 abort (); 870 } 871 872 873 /* 874 FUNCTION 875 bfd_set_section_size 876 877 SYNOPSIS 878 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val); 879 880 DESCRIPTION 881 Set @var{sec} to the size @var{val}. If the operation is 882 ok, then <<true>> is returned, else <<false>>. 883 884 Possible error returns: 885 o <<bfd_error_invalid_operation>> - 886 Writing has started to the BFD, so setting the size is invalid. 887 888 */ 889 890 boolean 891 bfd_set_section_size (abfd, ptr, val) 892 bfd *abfd; 893 sec_ptr ptr; 894 bfd_size_type val; 895 { 896 /* Once you've started writing to any section you cannot create or change 897 the size of any others. */ 898 899 if (abfd->output_has_begun) 900 { 901 bfd_set_error (bfd_error_invalid_operation); 902 return false; 903 } 904 905 ptr->_cooked_size = val; 906 ptr->_raw_size = val; 907 908 return true; 909 } 910 911 /* 912 FUNCTION 913 bfd_set_section_contents 914 915 SYNOPSIS 916 boolean bfd_set_section_contents 917 (bfd *abfd, 918 asection *section, 919 PTR data, 920 file_ptr offset, 921 bfd_size_type count); 922 923 924 DESCRIPTION 925 Sets the contents of the section @var{section} in BFD 926 @var{abfd} to the data starting in memory at @var{data}. The 927 data is written to the output section starting at offset 928 @var{offset} for @var{count} octets. 929 930 931 932 Normally <<true>> is returned, else <<false>>. Possible error 933 returns are: 934 o <<bfd_error_no_contents>> - 935 The output section does not have the <<SEC_HAS_CONTENTS>> 936 attribute, so nothing can be written to it. 937 o and some more too 938 939 This routine is front end to the back end function 940 <<_bfd_set_section_contents>>. 941 942 943 */ 944 945 #define bfd_get_section_size_now(abfd,sec) \ 946 (sec->reloc_done \ 947 ? bfd_get_section_size_after_reloc (sec) \ 948 : bfd_get_section_size_before_reloc (sec)) 949 950 boolean 951 bfd_set_section_contents (abfd, section, location, offset, count) 952 bfd *abfd; 953 sec_ptr section; 954 PTR location; 955 file_ptr offset; 956 bfd_size_type count; 957 { 958 bfd_size_type sz; 959 960 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS)) 961 { 962 bfd_set_error (bfd_error_no_contents); 963 return (false); 964 } 965 966 if (offset < 0) 967 { 968 bad_val: 969 bfd_set_error (bfd_error_bad_value); 970 return false; 971 } 972 sz = bfd_get_section_size_now (abfd, section); 973 if ((bfd_size_type) offset > sz 974 || count > sz 975 || offset + count > sz) 976 goto bad_val; 977 978 switch (abfd->direction) 979 { 980 case read_direction: 981 case no_direction: 982 bfd_set_error (bfd_error_invalid_operation); 983 return false; 984 985 case write_direction: 986 break; 987 988 case both_direction: 989 /* File is opened for update. `output_has_begun' some time ago when 990 the file was created. Do not recompute sections sizes or alignments 991 in _bfd_set_section_content. */ 992 abfd->output_has_begun = true; 993 break; 994 } 995 996 if (BFD_SEND (abfd, _bfd_set_section_contents, 997 (abfd, section, location, offset, count))) 998 { 999 abfd->output_has_begun = true; 1000 return true; 1001 } 1002 1003 return false; 1004 } 1005 1006 /* 1007 FUNCTION 1008 bfd_get_section_contents 1009 1010 SYNOPSIS 1011 boolean bfd_get_section_contents 1012 (bfd *abfd, asection *section, PTR location, 1013 file_ptr offset, bfd_size_type count); 1014 1015 DESCRIPTION 1016 Read data from @var{section} in BFD @var{abfd} 1017 into memory starting at @var{location}. The data is read at an 1018 offset of @var{offset} from the start of the input section, 1019 and is read for @var{count} bytes. 1020 1021 If the contents of a constructor with the <<SEC_CONSTRUCTOR>> 1022 flag set are requested or if the section does not have the 1023 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled 1024 with zeroes. If no errors occur, <<true>> is returned, else 1025 <<false>>. 1026 1027 1028 1029 */ 1030 boolean 1031 bfd_get_section_contents (abfd, section, location, offset, count) 1032 bfd *abfd; 1033 sec_ptr section; 1034 PTR location; 1035 file_ptr offset; 1036 bfd_size_type count; 1037 { 1038 bfd_size_type sz; 1039 1040 if (section->flags & SEC_CONSTRUCTOR) 1041 { 1042 memset (location, 0, (unsigned) count); 1043 return true; 1044 } 1045 1046 if (offset < 0) 1047 { 1048 bad_val: 1049 bfd_set_error (bfd_error_bad_value); 1050 return false; 1051 } 1052 /* Even if reloc_done is true, this function reads unrelocated 1053 contents, so we want the raw size. */ 1054 sz = section->_raw_size; 1055 if ((bfd_size_type) offset > sz || count > sz || offset + count > sz) 1056 goto bad_val; 1057 1058 if (count == 0) 1059 /* Don't bother. */ 1060 return true; 1061 1062 if ((section->flags & SEC_HAS_CONTENTS) == 0) 1063 { 1064 memset (location, 0, (unsigned) count); 1065 return true; 1066 } 1067 1068 if ((section->flags & SEC_IN_MEMORY) != 0) 1069 { 1070 memcpy (location, section->contents + offset, (size_t) count); 1071 return true; 1072 } 1073 1074 return BFD_SEND (abfd, _bfd_get_section_contents, 1075 (abfd, section, location, offset, count)); 1076 } 1077 1078 /* 1079 FUNCTION 1080 bfd_copy_private_section_data 1081 1082 SYNOPSIS 1083 boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec); 1084 1085 DESCRIPTION 1086 Copy private section information from @var{isec} in the BFD 1087 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 1088 Return <<true>> on success, <<false>> on error. Possible error 1089 returns are: 1090 1091 o <<bfd_error_no_memory>> - 1092 Not enough memory exists to create private data for @var{osec}. 1093 1094 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 1095 . BFD_SEND (obfd, _bfd_copy_private_section_data, \ 1096 . (ibfd, isection, obfd, osection)) 1097 */ 1098 1099 /* 1100 FUNCTION 1101 _bfd_strip_section_from_output 1102 1103 SYNOPSIS 1104 void _bfd_strip_section_from_output 1105 (struct bfd_link_info *info, asection *section); 1106 1107 DESCRIPTION 1108 Remove @var{section} from the output. If the output section 1109 becomes empty, remove it from the output bfd. @var{info} may 1110 be NULL; if it is not, it is used to decide whether the output 1111 section is empty. 1112 */ 1113 void 1114 _bfd_strip_section_from_output (info, s) 1115 struct bfd_link_info *info; 1116 asection *s; 1117 { 1118 asection **spp, *os; 1119 struct bfd_link_order *p, *pp; 1120 boolean keep_os; 1121 1122 /* Excise the input section from the link order. 1123 1124 FIXME: For all calls that I can see to this function, the link 1125 orders have not yet been set up. So why are we checking them? -- 1126 Ian */ 1127 os = s->output_section; 1128 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next) 1129 if (p->type == bfd_indirect_link_order 1130 && p->u.indirect.section == s) 1131 { 1132 if (pp) 1133 pp->next = p->next; 1134 else 1135 os->link_order_head = p->next; 1136 if (!p->next) 1137 os->link_order_tail = pp; 1138 break; 1139 } 1140 1141 keep_os = os->link_order_head != NULL; 1142 1143 if (! keep_os && info != NULL) 1144 { 1145 bfd *abfd; 1146 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) 1147 { 1148 asection *is; 1149 for (is = abfd->sections; is != NULL; is = is->next) 1150 { 1151 if (is != s && is->output_section == os) 1152 break; 1153 } 1154 if (is != NULL) 1155 break; 1156 } 1157 if (abfd != NULL) 1158 keep_os = true; 1159 } 1160 1161 /* If the output section is empty, remove it too. Careful about sections 1162 that have been discarded in the link script -- they are mapped to 1163 bfd_abs_section, which has no owner. */ 1164 if (!keep_os && os->owner != NULL) 1165 { 1166 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next) 1167 if (*spp == os) 1168 { 1169 *spp = os->next; 1170 os->owner->section_count--; 1171 break; 1172 } 1173 } 1174 } 1175