section.c revision 78828
1/* Object file "section" support for the BFD library. 2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 3 2000, 2001 4 Free Software Foundation, Inc. 5 Written by Cygnus Support. 6 7This file is part of BFD, the Binary File Descriptor library. 8 9This program is free software; you can redistribute it and/or modify 10it under the terms of the GNU General Public License as published by 11the Free Software Foundation; either version 2 of the License, or 12(at your option) any later version. 13 14This program is distributed in the hope that it will be useful, 15but WITHOUT ANY WARRANTY; without even the implied warranty of 16MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17GNU General Public License for more details. 18 19You should have received a copy of the GNU General Public License 20along with this program; if not, write to the Free Software 21Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 22 23/* 24SECTION 25 Sections 26 27 The raw data contained within a BFD is maintained through the 28 section abstraction. A single BFD may have any number of 29 sections. It keeps hold of them by pointing to the first; 30 each one points to the next in the list. 31 32 Sections are supported in BFD in <<section.c>>. 33 34@menu 35@* Section Input:: 36@* Section Output:: 37@* typedef asection:: 38@* section prototypes:: 39@end menu 40 41INODE 42Section Input, Section Output, Sections, Sections 43SUBSECTION 44 Section input 45 46 When a BFD is opened for reading, the section structures are 47 created and attached to the BFD. 48 49 Each section has a name which describes the section in the 50 outside world---for example, <<a.out>> would contain at least 51 three sections, called <<.text>>, <<.data>> and <<.bss>>. 52 53 Names need not be unique; for example a COFF file may have several 54 sections named <<.data>>. 55 56 Sometimes a BFD will contain more than the ``natural'' number of 57 sections. A back end may attach other sections containing 58 constructor data, or an application may add a section (using 59 <<bfd_make_section>>) to the sections attached to an already open 60 BFD. For example, the linker creates an extra section 61 <<COMMON>> for each input file's BFD to hold information about 62 common storage. 63 64 The raw data is not necessarily read in when 65 the section descriptor is created. Some targets may leave the 66 data in place until a <<bfd_get_section_contents>> call is 67 made. Other back ends may read in all the data at once. For 68 example, an S-record file has to be read once to determine the 69 size of the data. An IEEE-695 file doesn't contain raw data in 70 sections, but data and relocation expressions intermixed, so 71 the data area has to be parsed to get out the data and 72 relocations. 73 74INODE 75Section Output, typedef asection, Section Input, Sections 76 77SUBSECTION 78 Section output 79 80 To write a new object style BFD, the various sections to be 81 written have to be created. They are attached to the BFD in 82 the same way as input sections; data is written to the 83 sections using <<bfd_set_section_contents>>. 84 85 Any program that creates or combines sections (e.g., the assembler 86 and linker) must use the <<asection>> fields <<output_section>> and 87 <<output_offset>> to indicate the file sections to which each 88 section must be written. (If the section is being created from 89 scratch, <<output_section>> should probably point to the section 90 itself and <<output_offset>> should probably be zero.) 91 92 The data to be written comes from input sections attached 93 (via <<output_section>> pointers) to 94 the output sections. The output section structure can be 95 considered a filter for the input section: the output section 96 determines the vma of the output data and the name, but the 97 input section determines the offset into the output section of 98 the data to be written. 99 100 E.g., to create a section "O", starting at 0x100, 0x123 long, 101 containing two subsections, "A" at offset 0x0 (i.e., at vma 102 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>> 103 structures would look like: 104 105| section name "A" 106| output_offset 0x00 107| size 0x20 108| output_section -----------> section name "O" 109| | vma 0x100 110| section name "B" | size 0x123 111| output_offset 0x20 | 112| size 0x103 | 113| output_section --------| 114 115SUBSECTION 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#include "bfd.h" 137#include "sysdep.h" 138#include "libbfd.h" 139#include "bfdlink.h" 140 141/* 142DOCDD 143INODE 144typedef asection, section prototypes, Section Output, Sections 145SUBSECTION 146 typedef asection 147 148 Here is the section structure: 149 150CODE_FRAGMENT 151. 152.{* This structure is used for a comdat section, as in PE. A comdat 153. section is associated with a particular symbol. When the linker 154. sees a comdat section, it keeps only one of the sections with a 155. given name and associated with a given symbol. *} 156. 157.struct bfd_comdat_info 158.{ 159. {* The name of the symbol associated with a comdat section. *} 160. const char *name; 161. 162. {* The local symbol table index of the symbol associated with a 163. comdat section. This is only meaningful to the object file format 164. specific code; it is not an index into the list returned by 165. bfd_canonicalize_symtab. *} 166. long symbol; 167.}; 168. 169.typedef struct sec 170.{ 171. {* The name of the section; the name isn't a copy, the pointer is 172. the same as that passed to bfd_make_section. *} 173. 174. const char *name; 175. 176. {* A unique sequence number. *} 177. 178. int id; 179. 180. {* Which section is it; 0..nth. *} 181. 182. int index; 183. 184. {* The next section in the list belonging to the BFD, or NULL. *} 185. 186. struct sec *next; 187. 188. {* The field flags contains attributes of the section. Some 189. flags are read in from the object file, and some are 190. synthesized from other information. *} 191. 192. flagword flags; 193. 194.#define SEC_NO_FLAGS 0x000 195. 196. {* Tells the OS to allocate space for this section when loading. 197. This is clear for a section containing debug information only. *} 198.#define SEC_ALLOC 0x001 199. 200. {* Tells the OS to load the section from the file when loading. 201. This is clear for a .bss section. *} 202.#define SEC_LOAD 0x002 203. 204. {* The section contains data still to be relocated, so there is 205. some relocation information too. *} 206.#define SEC_RELOC 0x004 207. 208.#if 0 {* Obsolete ? *} 209.#define SEC_BALIGN 0x008 210.#endif 211. 212. {* A signal to the OS that the section contains read only data. *} 213.#define SEC_READONLY 0x010 214. 215. {* The section contains code only. *} 216.#define SEC_CODE 0x020 217. 218. {* The section contains data only. *} 219.#define SEC_DATA 0x040 220. 221. {* The section will reside in ROM. *} 222.#define SEC_ROM 0x080 223. 224. {* The section contains constructor information. This section 225. type is used by the linker to create lists of constructors and 226. destructors used by <<g++>>. When a back end sees a symbol 227. which should be used in a constructor list, it creates a new 228. section for the type of name (e.g., <<__CTOR_LIST__>>), attaches 229. the symbol to it, and builds a relocation. To build the lists 230. of constructors, all the linker has to do is catenate all the 231. sections called <<__CTOR_LIST__>> and relocate the data 232. contained within - exactly the operations it would peform on 233. standard data. *} 234.#define SEC_CONSTRUCTOR 0x100 235. 236. {* The section is a constructor, and should be placed at the 237. end of the text, data, or bss section(?). *} 238.#define SEC_CONSTRUCTOR_TEXT 0x1100 239.#define SEC_CONSTRUCTOR_DATA 0x2100 240.#define SEC_CONSTRUCTOR_BSS 0x3100 241. 242. {* The section has contents - a data section could be 243. <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be 244. <<SEC_HAS_CONTENTS>> *} 245.#define SEC_HAS_CONTENTS 0x200 246. 247. {* An instruction to the linker to not output the section 248. even if it has information which would normally be written. *} 249.#define SEC_NEVER_LOAD 0x400 250. 251. {* The section is a COFF shared library section. This flag is 252. only for the linker. If this type of section appears in 253. the input file, the linker must copy it to the output file 254. without changing the vma or size. FIXME: Although this 255. was originally intended to be general, it really is COFF 256. specific (and the flag was renamed to indicate this). It 257. might be cleaner to have some more general mechanism to 258. allow the back end to control what the linker does with 259. sections. *} 260.#define SEC_COFF_SHARED_LIBRARY 0x800 261. 262. {* The section has GOT references. This flag is only for the 263. linker, and is currently only used by the elf32-hppa back end. 264. It will be set if global offset table references were detected 265. in this section, which indicate to the linker that the section 266. contains PIC code, and must be handled specially when doing a 267. static link. *} 268.#define SEC_HAS_GOT_REF 0x4000 269. 270. {* The section contains common symbols (symbols may be defined 271. multiple times, the value of a symbol is the amount of 272. space it requires, and the largest symbol value is the one 273. used). Most targets have exactly one of these (which we 274. translate to bfd_com_section_ptr), but ECOFF has two. *} 275.#define SEC_IS_COMMON 0x8000 276. 277. {* The section contains only debugging information. For 278. example, this is set for ELF .debug and .stab sections. 279. strip tests this flag to see if a section can be 280. discarded. *} 281.#define SEC_DEBUGGING 0x10000 282. 283. {* The contents of this section are held in memory pointed to 284. by the contents field. This is checked by bfd_get_section_contents, 285. and the data is retrieved from memory if appropriate. *} 286.#define SEC_IN_MEMORY 0x20000 287. 288. {* The contents of this section are to be excluded by the 289. linker for executable and shared objects unless those 290. objects are to be further relocated. *} 291.#define SEC_EXCLUDE 0x40000 292. 293. {* The contents of this section are to be sorted by the 294. based on the address specified in the associated symbol 295. table. *} 296.#define SEC_SORT_ENTRIES 0x80000 297. 298. {* When linking, duplicate sections of the same name should be 299. discarded, rather than being combined into a single section as 300. is usually done. This is similar to how common symbols are 301. handled. See SEC_LINK_DUPLICATES below. *} 302.#define SEC_LINK_ONCE 0x100000 303. 304. {* If SEC_LINK_ONCE is set, this bitfield describes how the linker 305. should handle duplicate sections. *} 306.#define SEC_LINK_DUPLICATES 0x600000 307. 308. {* This value for SEC_LINK_DUPLICATES means that duplicate 309. sections with the same name should simply be discarded. *} 310.#define SEC_LINK_DUPLICATES_DISCARD 0x0 311. 312. {* This value for SEC_LINK_DUPLICATES means that the linker 313. should warn if there are any duplicate sections, although 314. it should still only link one copy. *} 315.#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000 316. 317. {* This value for SEC_LINK_DUPLICATES means that the linker 318. should warn if any duplicate sections are a different size. *} 319.#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000 320. 321. {* This value for SEC_LINK_DUPLICATES means that the linker 322. should warn if any duplicate sections contain different 323. contents. *} 324.#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000 325. 326. {* This section was created by the linker as part of dynamic 327. relocation or other arcane processing. It is skipped when 328. going through the first-pass output, trusting that someone 329. else up the line will take care of it later. *} 330.#define SEC_LINKER_CREATED 0x800000 331. 332. {* This section should not be subject to garbage collection. *} 333.#define SEC_KEEP 0x1000000 334. 335. {* This section contains "short" data, and should be placed 336. "near" the GP. *} 337.#define SEC_SMALL_DATA 0x2000000 338. 339. {* This section contains data which may be shared with other 340. executables or shared objects. *} 341.#define SEC_SHARED 0x4000000 342. 343. {* When a section with this flag is being linked, then if the size of 344. the input section is less than a page, it should not cross a page 345. boundary. If the size of the input section is one page or more, it 346. should be aligned on a page boundary. *} 347.#define SEC_BLOCK 0x8000000 348. 349. {* Conditionally link this section; do not link if there are no 350. references found to any symbol in the section. *} 351.#define SEC_CLINK 0x10000000 352. 353. {* End of section flags. *} 354. 355. {* Some internal packed boolean fields. *} 356. 357. {* See the vma field. *} 358. unsigned int user_set_vma : 1; 359. 360. {* Whether relocations have been processed. *} 361. unsigned int reloc_done : 1; 362. 363. {* A mark flag used by some of the linker backends. *} 364. unsigned int linker_mark : 1; 365. 366. {* Another mark flag used by some of the linker backends. Set for 367. output sections that have a input section. *} 368. unsigned int linker_has_input : 1; 369. 370. {* A mark flag used by some linker backends for garbage collection. *} 371. unsigned int gc_mark : 1; 372. 373. {* Used by the ELF code to mark sections which have been allocated to segments. *} 374. unsigned int segment_mark : 1; 375. 376. {* End of internal packed boolean fields. *} 377. 378. {* The virtual memory address of the section - where it will be 379. at run time. The symbols are relocated against this. The 380. user_set_vma flag is maintained by bfd; if it's not set, the 381. backend can assign addresses (for example, in <<a.out>>, where 382. the default address for <<.data>> is dependent on the specific 383. target and various flags). *} 384. 385. bfd_vma vma; 386. 387. {* The load address of the section - where it would be in a 388. rom image; really only used for writing section header 389. information. *} 390. 391. bfd_vma lma; 392. 393. {* The size of the section in octets, as it will be output. 394. Contains a value even if the section has no contents (e.g., the 395. size of <<.bss>>). This will be filled in after relocation. *} 396. 397. bfd_size_type _cooked_size; 398. 399. {* The original size on disk of the section, in octets. Normally this 400. value is the same as the size, but if some relaxing has 401. been done, then this value will be bigger. *} 402. 403. bfd_size_type _raw_size; 404. 405. {* If this section is going to be output, then this value is the 406. offset in *bytes* into the output section of the first byte in the 407. input section (byte ==> smallest addressable unit on the 408. target). In most cases, if this was going to start at the 409. 100th octet (8-bit quantity) in the output section, this value 410. would be 100. However, if the target byte size is 16 bits 411. (bfd_octets_per_byte is "2"), this value would be 50. *} 412. 413. bfd_vma output_offset; 414. 415. {* The output section through which to map on output. *} 416. 417. struct sec *output_section; 418. 419. {* The alignment requirement of the section, as an exponent of 2 - 420. e.g., 3 aligns to 2^3 (or 8). *} 421. 422. unsigned int alignment_power; 423. 424. {* If an input section, a pointer to a vector of relocation 425. records for the data in this section. *} 426. 427. struct reloc_cache_entry *relocation; 428. 429. {* If an output section, a pointer to a vector of pointers to 430. relocation records for the data in this section. *} 431. 432. struct reloc_cache_entry **orelocation; 433. 434. {* The number of relocation records in one of the above *} 435. 436. unsigned reloc_count; 437. 438. {* Information below is back end specific - and not always used 439. or updated. *} 440. 441. {* File position of section data. *} 442. 443. file_ptr filepos; 444. 445. {* File position of relocation info. *} 446. 447. file_ptr rel_filepos; 448. 449. {* File position of line data. *} 450. 451. file_ptr line_filepos; 452. 453. {* Pointer to data for applications. *} 454. 455. PTR userdata; 456. 457. {* If the SEC_IN_MEMORY flag is set, this points to the actual 458. contents. *} 459. unsigned char *contents; 460. 461. {* Attached line number information. *} 462. 463. alent *lineno; 464. 465. {* Number of line number records. *} 466. 467. unsigned int lineno_count; 468. 469. {* Optional information about a COMDAT entry; NULL if not COMDAT. *} 470. 471. struct bfd_comdat_info *comdat; 472. 473. {* Points to the kept section if this section is a link-once section, 474. and is discarded. *} 475. struct sec *kept_section; 476. 477. {* When a section is being output, this value changes as more 478. linenumbers are written out. *} 479. 480. file_ptr moving_line_filepos; 481. 482. {* What the section number is in the target world. *} 483. 484. int target_index; 485. 486. PTR used_by_bfd; 487. 488. {* If this is a constructor section then here is a list of the 489. relocations created to relocate items within it. *} 490. 491. struct relent_chain *constructor_chain; 492. 493. {* The BFD which owns the section. *} 494. 495. bfd *owner; 496. 497. {* A symbol which points at this section only *} 498. struct symbol_cache_entry *symbol; 499. struct symbol_cache_entry **symbol_ptr_ptr; 500. 501. struct bfd_link_order *link_order_head; 502. struct bfd_link_order *link_order_tail; 503.} asection ; 504. 505.{* These sections are global, and are managed by BFD. The application 506. and target back end are not permitted to change the values in 507. these sections. New code should use the section_ptr macros rather 508. than referring directly to the const sections. The const sections 509. may eventually vanish. *} 510.#define BFD_ABS_SECTION_NAME "*ABS*" 511.#define BFD_UND_SECTION_NAME "*UND*" 512.#define BFD_COM_SECTION_NAME "*COM*" 513.#define BFD_IND_SECTION_NAME "*IND*" 514. 515.{* the absolute section *} 516.extern const asection bfd_abs_section; 517.#define bfd_abs_section_ptr ((asection *) &bfd_abs_section) 518.#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) 519.{* Pointer to the undefined section *} 520.extern const asection bfd_und_section; 521.#define bfd_und_section_ptr ((asection *) &bfd_und_section) 522.#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) 523.{* Pointer to the common section *} 524.extern const asection bfd_com_section; 525.#define bfd_com_section_ptr ((asection *) &bfd_com_section) 526.{* Pointer to the indirect section *} 527.extern const asection bfd_ind_section; 528.#define bfd_ind_section_ptr ((asection *) &bfd_ind_section) 529.#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) 530. 531.extern const struct symbol_cache_entry * const bfd_abs_symbol; 532.extern const struct symbol_cache_entry * const bfd_com_symbol; 533.extern const struct symbol_cache_entry * const bfd_und_symbol; 534.extern const struct symbol_cache_entry * const bfd_ind_symbol; 535.#define bfd_get_section_size_before_reloc(section) \ 536. ((section)->reloc_done ? (abort (), (bfd_size_type) 1) \ 537. : (section)->_raw_size) 538.#define bfd_get_section_size_after_reloc(section) \ 539. ((section)->reloc_done ? (section)->_cooked_size \ 540. : (abort (), (bfd_size_type) 1)) 541*/ 542 543/* We use a macro to initialize the static asymbol structures because 544 traditional C does not permit us to initialize a union member while 545 gcc warns if we don't initialize it. */ 546 /* the_bfd, name, value, attr, section [, udata] */ 547#ifdef __STDC__ 548#define GLOBAL_SYM_INIT(NAME, SECTION) \ 549 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION, { 0 }} 550#else 551#define GLOBAL_SYM_INIT(NAME, SECTION) \ 552 { 0, NAME, 0, BSF_SECTION_SYM, (asection *) SECTION } 553#endif 554 555/* These symbols are global, not specific to any BFD. Therefore, anything 556 that tries to change them is broken, and should be repaired. */ 557 558static const asymbol global_syms[] = 559{ 560 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, &bfd_com_section), 561 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, &bfd_und_section), 562 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, &bfd_abs_section), 563 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, &bfd_ind_section) 564}; 565 566#define STD_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ 567 const asymbol * const SYM = (asymbol *) &global_syms[IDX]; \ 568 const asection SEC = \ 569 /* name, id, index, next, flags, user_set_vma, reloc_done, */ \ 570 { NAME, IDX, 0, NULL, FLAGS, 0, 0, \ 571 \ 572 /* linker_mark, linker_has_input, gc_mark, segment_mark, */ \ 573 0, 0, 1, 0, \ 574 \ 575 /* vma, lma, _cooked_size, _raw_size, */ \ 576 0, 0, 0, 0, \ 577 \ 578 /* output_offset, output_section, alignment_power, */ \ 579 0, (struct sec *) &SEC, 0, \ 580 \ 581 /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ 582 NULL, NULL, 0, 0, 0, \ 583 \ 584 /* line_filepos, userdata, contents, lineno, lineno_count, */ \ 585 0, NULL, NULL, NULL, 0, \ 586 \ 587 /* comdat, kept_section, moving_line_filepos, target_index, */ \ 588 NULL, NULL, 0, 0, \ 589 \ 590 /* used_by_bfd, constructor_chain, owner, */ \ 591 NULL, NULL, NULL, \ 592 \ 593 /* symbol, */ \ 594 (struct symbol_cache_entry *) &global_syms[IDX], \ 595 \ 596 /* symbol_ptr_ptr, */ \ 597 (struct symbol_cache_entry **) &SYM, \ 598 \ 599 /* link_order_head, link_order_tail */ \ 600 NULL, NULL \ 601 } 602 603STD_SECTION (bfd_com_section, SEC_IS_COMMON, bfd_com_symbol, 604 BFD_COM_SECTION_NAME, 0); 605STD_SECTION (bfd_und_section, 0, bfd_und_symbol, BFD_UND_SECTION_NAME, 1); 606STD_SECTION (bfd_abs_section, 0, bfd_abs_symbol, BFD_ABS_SECTION_NAME, 2); 607STD_SECTION (bfd_ind_section, 0, bfd_ind_symbol, BFD_IND_SECTION_NAME, 3); 608#undef STD_SECTION 609 610/* 611DOCDD 612INODE 613section prototypes, , typedef asection, Sections 614SUBSECTION 615 Section prototypes 616 617These are the functions exported by the section handling part of BFD. 618*/ 619 620/* 621FUNCTION 622 bfd_get_section_by_name 623 624SYNOPSIS 625 asection *bfd_get_section_by_name(bfd *abfd, const char *name); 626 627DESCRIPTION 628 Run through @var{abfd} and return the one of the 629 <<asection>>s whose name matches @var{name}, otherwise <<NULL>>. 630 @xref{Sections}, for more information. 631 632 This should only be used in special cases; the normal way to process 633 all sections of a given name is to use <<bfd_map_over_sections>> and 634 <<strcmp>> on the name (or better yet, base it on the section flags 635 or something else) for each section. 636*/ 637 638asection * 639bfd_get_section_by_name (abfd, name) 640 bfd *abfd; 641 const char *name; 642{ 643 asection *sect; 644 645 for (sect = abfd->sections; sect != NULL; sect = sect->next) 646 if (!strcmp (sect->name, name)) 647 return sect; 648 return NULL; 649} 650 651/* 652FUNCTION 653 bfd_get_unique_section_name 654 655SYNOPSIS 656 char *bfd_get_unique_section_name(bfd *abfd, 657 const char *templat, 658 int *count); 659 660DESCRIPTION 661 Invent a section name that is unique in @var{abfd} by tacking 662 a dot and a digit suffix onto the original @var{templat}. If 663 @var{count} is non-NULL, then it specifies the first number 664 tried as a suffix to generate a unique name. The value 665 pointed to by @var{count} will be incremented in this case. 666*/ 667 668char * 669bfd_get_unique_section_name (abfd, templat, count) 670 bfd *abfd; 671 const char *templat; 672 int *count; 673{ 674 int num; 675 unsigned int len; 676 char *sname; 677 678 len = strlen (templat); 679 sname = bfd_malloc (len + 8); 680 if (sname == NULL) 681 return NULL; 682 strcpy (sname, templat); 683 num = 1; 684 if (count != NULL) 685 num = *count; 686 687 do 688 { 689 /* If we have a million sections, something is badly wrong. */ 690 if (num > 999999) 691 abort (); 692 sprintf (sname + len, ".%d", num++); 693 } 694 while (bfd_get_section_by_name (abfd, sname) != NULL); 695 696 if (count != NULL) 697 *count = num; 698 return sname; 699} 700 701/* 702FUNCTION 703 bfd_make_section_old_way 704 705SYNOPSIS 706 asection *bfd_make_section_old_way(bfd *abfd, const char *name); 707 708DESCRIPTION 709 Create a new empty section called @var{name} 710 and attach it to the end of the chain of sections for the 711 BFD @var{abfd}. An attempt to create a section with a name which 712 is already in use returns its pointer without changing the 713 section chain. 714 715 It has the funny name since this is the way it used to be 716 before it was rewritten.... 717 718 Possible errors are: 719 o <<bfd_error_invalid_operation>> - 720 If output has already started for this BFD. 721 o <<bfd_error_no_memory>> - 722 If memory allocation fails. 723 724*/ 725 726asection * 727bfd_make_section_old_way (abfd, name) 728 bfd *abfd; 729 const char *name; 730{ 731 asection *sec = bfd_get_section_by_name (abfd, name); 732 if (sec == (asection *) NULL) 733 { 734 sec = bfd_make_section (abfd, name); 735 } 736 return sec; 737} 738 739/* 740FUNCTION 741 bfd_make_section_anyway 742 743SYNOPSIS 744 asection *bfd_make_section_anyway(bfd *abfd, const char *name); 745 746DESCRIPTION 747 Create a new empty section called @var{name} and attach it to the end of 748 the chain of sections for @var{abfd}. Create a new section even if there 749 is already a section with that name. 750 751 Return <<NULL>> and set <<bfd_error>> on error; possible errors are: 752 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}. 753 o <<bfd_error_no_memory>> - If memory allocation fails. 754*/ 755 756sec_ptr 757bfd_make_section_anyway (abfd, name) 758 bfd *abfd; 759 const char *name; 760{ 761 static int section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */ 762 asection *newsect; 763 asection **prev = &abfd->sections; 764 asection *sect = abfd->sections; 765 766 if (abfd->output_has_begun) 767 { 768 bfd_set_error (bfd_error_invalid_operation); 769 return NULL; 770 } 771 772 while (sect) 773 { 774 prev = §->next; 775 sect = sect->next; 776 } 777 778 newsect = (asection *) bfd_zalloc (abfd, sizeof (asection)); 779 if (newsect == NULL) 780 return NULL; 781 782 newsect->name = name; 783 newsect->id = section_id++; 784 newsect->index = abfd->section_count++; 785 newsect->flags = SEC_NO_FLAGS; 786 787 newsect->userdata = NULL; 788 newsect->contents = NULL; 789 newsect->next = (asection *) NULL; 790 newsect->relocation = (arelent *) NULL; 791 newsect->reloc_count = 0; 792 newsect->line_filepos = 0; 793 newsect->owner = abfd; 794 newsect->comdat = NULL; 795 newsect->kept_section = NULL; 796 797 /* Create a symbol whos only job is to point to this section. This is 798 useful for things like relocs which are relative to the base of a 799 section. */ 800 newsect->symbol = bfd_make_empty_symbol (abfd); 801 if (newsect->symbol == NULL) 802 { 803 bfd_release (abfd, newsect); 804 return NULL; 805 } 806 newsect->symbol->name = name; 807 newsect->symbol->value = 0; 808 newsect->symbol->section = newsect; 809 newsect->symbol->flags = BSF_SECTION_SYM; 810 811 newsect->symbol_ptr_ptr = &newsect->symbol; 812 813 if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) 814 { 815 bfd_release (abfd, newsect); 816 return NULL; 817 } 818 819 *prev = newsect; 820 return newsect; 821} 822 823/* 824FUNCTION 825 bfd_make_section 826 827SYNOPSIS 828 asection *bfd_make_section(bfd *, const char *name); 829 830DESCRIPTION 831 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling 832 bfd_set_error ()) without changing the section chain if there is already a 833 section named @var{name}. If there is an error, return <<NULL>> and set 834 <<bfd_error>>. 835*/ 836 837asection * 838bfd_make_section (abfd, name) 839 bfd *abfd; 840 const char *name; 841{ 842 asection *sect = abfd->sections; 843 844 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0) 845 { 846 return bfd_abs_section_ptr; 847 } 848 if (strcmp (name, BFD_COM_SECTION_NAME) == 0) 849 { 850 return bfd_com_section_ptr; 851 } 852 if (strcmp (name, BFD_UND_SECTION_NAME) == 0) 853 { 854 return bfd_und_section_ptr; 855 } 856 857 if (strcmp (name, BFD_IND_SECTION_NAME) == 0) 858 { 859 return bfd_ind_section_ptr; 860 } 861 862 while (sect) 863 { 864 if (!strcmp (sect->name, name)) 865 return NULL; 866 sect = sect->next; 867 } 868 869 /* The name is not already used; go ahead and make a new section. */ 870 return bfd_make_section_anyway (abfd, name); 871} 872 873/* 874FUNCTION 875 bfd_set_section_flags 876 877SYNOPSIS 878 boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags); 879 880DESCRIPTION 881 Set the attributes of the section @var{sec} in the BFD 882 @var{abfd} to the value @var{flags}. Return <<true>> on success, 883 <<false>> on error. Possible error returns are: 884 885 o <<bfd_error_invalid_operation>> - 886 The section cannot have one or more of the attributes 887 requested. For example, a .bss section in <<a.out>> may not 888 have the <<SEC_HAS_CONTENTS>> field set. 889 890*/ 891 892/*ARGSUSED*/ 893boolean 894bfd_set_section_flags (abfd, section, flags) 895 bfd *abfd ATTRIBUTE_UNUSED; 896 sec_ptr section; 897 flagword flags; 898{ 899#if 0 900 /* If you try to copy a text section from an input file (where it 901 has the SEC_CODE flag set) to an output file, this loses big if 902 the bfd_applicable_section_flags (abfd) doesn't have the SEC_CODE 903 set - which it doesn't, at least not for a.out. FIXME */ 904 905 if ((flags & bfd_applicable_section_flags (abfd)) != flags) 906 { 907 bfd_set_error (bfd_error_invalid_operation); 908 return false; 909 } 910#endif 911 912 section->flags = flags; 913 return true; 914} 915 916/* 917FUNCTION 918 bfd_map_over_sections 919 920SYNOPSIS 921 void bfd_map_over_sections(bfd *abfd, 922 void (*func) (bfd *abfd, 923 asection *sect, 924 PTR obj), 925 PTR obj); 926 927DESCRIPTION 928 Call the provided function @var{func} for each section 929 attached to the BFD @var{abfd}, passing @var{obj} as an 930 argument. The function will be called as if by 931 932| func(abfd, the_section, obj); 933 934 This is the prefered method for iterating over sections; an 935 alternative would be to use a loop: 936 937| section *p; 938| for (p = abfd->sections; p != NULL; p = p->next) 939| func(abfd, p, ...) 940 941*/ 942 943/*VARARGS2*/ 944void 945bfd_map_over_sections (abfd, operation, user_storage) 946 bfd *abfd; 947 void (*operation) PARAMS ((bfd * abfd, asection * sect, PTR obj)); 948 PTR user_storage; 949{ 950 asection *sect; 951 unsigned int i = 0; 952 953 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next) 954 (*operation) (abfd, sect, user_storage); 955 956 if (i != abfd->section_count) /* Debugging */ 957 abort (); 958} 959 960/* 961FUNCTION 962 bfd_set_section_size 963 964SYNOPSIS 965 boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val); 966 967DESCRIPTION 968 Set @var{sec} to the size @var{val}. If the operation is 969 ok, then <<true>> is returned, else <<false>>. 970 971 Possible error returns: 972 o <<bfd_error_invalid_operation>> - 973 Writing has started to the BFD, so setting the size is invalid. 974 975*/ 976 977boolean 978bfd_set_section_size (abfd, ptr, val) 979 bfd *abfd; 980 sec_ptr ptr; 981 bfd_size_type val; 982{ 983 /* Once you've started writing to any section you cannot create or change 984 the size of any others. */ 985 986 if (abfd->output_has_begun) 987 { 988 bfd_set_error (bfd_error_invalid_operation); 989 return false; 990 } 991 992 ptr->_cooked_size = val; 993 ptr->_raw_size = val; 994 995 return true; 996} 997 998/* 999FUNCTION 1000 bfd_set_section_contents 1001 1002SYNOPSIS 1003 boolean bfd_set_section_contents 1004 (bfd *abfd, 1005 asection *section, 1006 PTR data, 1007 file_ptr offset, 1008 bfd_size_type count); 1009 1010DESCRIPTION 1011 Sets the contents of the section @var{section} in BFD 1012 @var{abfd} to the data starting in memory at @var{data}. The 1013 data is written to the output section starting at offset 1014 @var{offset} for @var{count} octets. 1015 1016 Normally <<true>> is returned, else <<false>>. Possible error 1017 returns are: 1018 o <<bfd_error_no_contents>> - 1019 The output section does not have the <<SEC_HAS_CONTENTS>> 1020 attribute, so nothing can be written to it. 1021 o and some more too 1022 1023 This routine is front end to the back end function 1024 <<_bfd_set_section_contents>>. 1025 1026*/ 1027 1028#define bfd_get_section_size_now(abfd,sec) \ 1029(sec->reloc_done \ 1030 ? bfd_get_section_size_after_reloc (sec) \ 1031 : bfd_get_section_size_before_reloc (sec)) 1032 1033boolean 1034bfd_set_section_contents (abfd, section, location, offset, count) 1035 bfd *abfd; 1036 sec_ptr section; 1037 PTR location; 1038 file_ptr offset; 1039 bfd_size_type count; 1040{ 1041 bfd_size_type sz; 1042 1043 if (!(bfd_get_section_flags (abfd, section) & SEC_HAS_CONTENTS)) 1044 { 1045 bfd_set_error (bfd_error_no_contents); 1046 return (false); 1047 } 1048 1049 if (offset < 0) 1050 { 1051 bad_val: 1052 bfd_set_error (bfd_error_bad_value); 1053 return false; 1054 } 1055 sz = bfd_get_section_size_now (abfd, section); 1056 if ((bfd_size_type) offset > sz 1057 || count > sz 1058 || offset + count > sz) 1059 goto bad_val; 1060 1061 switch (abfd->direction) 1062 { 1063 case read_direction: 1064 case no_direction: 1065 bfd_set_error (bfd_error_invalid_operation); 1066 return false; 1067 1068 case write_direction: 1069 break; 1070 1071 case both_direction: 1072 /* File is opened for update. `output_has_begun' some time ago when 1073 the file was created. Do not recompute sections sizes or alignments 1074 in _bfd_set_section_content. */ 1075 abfd->output_has_begun = true; 1076 break; 1077 } 1078 1079 /* Record a copy of the data in memory if desired. */ 1080 if (section->contents 1081 && location != section->contents + offset) 1082 memcpy (section->contents + offset, location, count); 1083 1084 if (BFD_SEND (abfd, _bfd_set_section_contents, 1085 (abfd, section, location, offset, count))) 1086 { 1087 abfd->output_has_begun = true; 1088 return true; 1089 } 1090 1091 return false; 1092} 1093 1094/* 1095FUNCTION 1096 bfd_get_section_contents 1097 1098SYNOPSIS 1099 boolean bfd_get_section_contents 1100 (bfd *abfd, asection *section, PTR location, 1101 file_ptr offset, bfd_size_type count); 1102 1103DESCRIPTION 1104 Read data from @var{section} in BFD @var{abfd} 1105 into memory starting at @var{location}. The data is read at an 1106 offset of @var{offset} from the start of the input section, 1107 and is read for @var{count} bytes. 1108 1109 If the contents of a constructor with the <<SEC_CONSTRUCTOR>> 1110 flag set are requested or if the section does not have the 1111 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled 1112 with zeroes. If no errors occur, <<true>> is returned, else 1113 <<false>>. 1114 1115*/ 1116boolean 1117bfd_get_section_contents (abfd, section, location, offset, count) 1118 bfd *abfd; 1119 sec_ptr section; 1120 PTR location; 1121 file_ptr offset; 1122 bfd_size_type count; 1123{ 1124 bfd_size_type sz; 1125 1126 if (section->flags & SEC_CONSTRUCTOR) 1127 { 1128 memset (location, 0, (unsigned) count); 1129 return true; 1130 } 1131 1132 if (offset < 0) 1133 { 1134 bad_val: 1135 bfd_set_error (bfd_error_bad_value); 1136 return false; 1137 } 1138 /* Even if reloc_done is true, this function reads unrelocated 1139 contents, so we want the raw size. */ 1140 sz = section->_raw_size; 1141 if ((bfd_size_type) offset > sz || count > sz || offset + count > sz) 1142 goto bad_val; 1143 1144 if (count == 0) 1145 /* Don't bother. */ 1146 return true; 1147 1148 if ((section->flags & SEC_HAS_CONTENTS) == 0) 1149 { 1150 memset (location, 0, (unsigned) count); 1151 return true; 1152 } 1153 1154 if ((section->flags & SEC_IN_MEMORY) != 0) 1155 { 1156 memcpy (location, section->contents + offset, (size_t) count); 1157 return true; 1158 } 1159 1160 return BFD_SEND (abfd, _bfd_get_section_contents, 1161 (abfd, section, location, offset, count)); 1162} 1163 1164/* 1165FUNCTION 1166 bfd_copy_private_section_data 1167 1168SYNOPSIS 1169 boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec); 1170 1171DESCRIPTION 1172 Copy private section information from @var{isec} in the BFD 1173 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}. 1174 Return <<true>> on success, <<false>> on error. Possible error 1175 returns are: 1176 1177 o <<bfd_error_no_memory>> - 1178 Not enough memory exists to create private data for @var{osec}. 1179 1180.#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ 1181. BFD_SEND (obfd, _bfd_copy_private_section_data, \ 1182. (ibfd, isection, obfd, osection)) 1183*/ 1184 1185/* 1186FUNCTION 1187 _bfd_strip_section_from_output 1188 1189SYNOPSIS 1190 void _bfd_strip_section_from_output 1191 (struct bfd_link_info *info, asection *section); 1192 1193DESCRIPTION 1194 Remove @var{section} from the output. If the output section 1195 becomes empty, remove it from the output bfd. @var{info} may 1196 be NULL; if it is not, it is used to decide whether the output 1197 section is empty. 1198*/ 1199void 1200_bfd_strip_section_from_output (info, s) 1201 struct bfd_link_info *info; 1202 asection *s; 1203{ 1204 asection **spp, *os; 1205 struct bfd_link_order *p, *pp; 1206 boolean keep_os; 1207 1208 /* Excise the input section from the link order. 1209 1210 FIXME: For all calls that I can see to this function, the link 1211 orders have not yet been set up. So why are we checking them? -- 1212 Ian */ 1213 os = s->output_section; 1214 1215 /* Handle a section that wasn't output. */ 1216 if (os == NULL) 1217 return; 1218 1219 for (p = os->link_order_head, pp = NULL; p != NULL; pp = p, p = p->next) 1220 if (p->type == bfd_indirect_link_order 1221 && p->u.indirect.section == s) 1222 { 1223 if (pp) 1224 pp->next = p->next; 1225 else 1226 os->link_order_head = p->next; 1227 if (!p->next) 1228 os->link_order_tail = pp; 1229 break; 1230 } 1231 1232 keep_os = os->link_order_head != NULL; 1233 1234 if (! keep_os && info != NULL) 1235 { 1236 bfd *abfd; 1237 for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link_next) 1238 { 1239 asection *is; 1240 for (is = abfd->sections; is != NULL; is = is->next) 1241 { 1242 if (is != s && is->output_section == os) 1243 break; 1244 } 1245 if (is != NULL) 1246 break; 1247 } 1248 if (abfd != NULL) 1249 keep_os = true; 1250 } 1251 1252 /* If the output section is empty, remove it too. Careful about sections 1253 that have been discarded in the link script -- they are mapped to 1254 bfd_abs_section, which has no owner. */ 1255 if (!keep_os && os->owner != NULL) 1256 { 1257 for (spp = &os->owner->sections; *spp; spp = &(*spp)->next) 1258 if (*spp == os) 1259 { 1260 *spp = os->next; 1261 os->owner->section_count--; 1262 break; 1263 } 1264 } 1265} 1266