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1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2025 Free Software Foundation, Inc.
3 Written by Cygnus Support.
4
5 This file is part of BFD, the Binary File Descriptor library.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, 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.
69
70 INODE
71 Section Output, typedef asection, Section Input, Sections
72
73 SUBSECTION
74 Section output
75
76 To write a new object style BFD, the various sections to be
77 written have to be created. They are attached to the BFD in
78 the same way as input sections; data is written to the
79 sections using <<bfd_set_section_contents>>.
80
81 Any program that creates or combines sections (e.g., the assembler
82 and linker) must use the <<asection>> fields <<output_section>> and
83 <<output_offset>> to indicate the file sections to which each
84 section must be written. (If the section is being created from
85 scratch, <<output_section>> should probably point to the section
86 itself and <<output_offset>> should probably be zero.)
87
88 The data to be written comes from input sections attached
89 (via <<output_section>> pointers) to
90 the output sections. The output section structure can be
91 considered a filter for the input section: the output section
92 determines the vma of the output data and the name, but the
93 input section determines the offset into the output section of
94 the data to be written.
95
96 E.g., to create a section "O", starting at 0x100, 0x123 long,
97 containing two subsections, "A" at offset 0x0 (i.e., at vma
98 0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the <<asection>>
99 structures would look like:
100
101 | section name "A"
102 | output_offset 0x00
103 | size 0x20
104 | output_section -----------> section name "O"
105 | | vma 0x100
106 | section name "B" | size 0x123
107 | output_offset 0x20 |
108 | size 0x103 |
109 | output_section --------|
110
111 SUBSECTION
112 Link orders
113
114 The data within a section is stored in a @dfn{link_order}.
115 These are much like the fixups in <<gas>>. The link_order
116 abstraction allows a section to grow and shrink within itself.
117
118 A link_order knows how big it is, and which is the next
119 link_order and where the raw data for it is; it also points to
120 a list of relocations which apply to it.
121
122 The link_order is used by the linker to perform relaxing on
123 final code. The compiler creates code which is as big as
124 necessary to make it work without relaxing, and the user can
125 select whether to relax. Sometimes relaxing takes a lot of
126 time. The linker runs around the relocations to see if any
127 are attached to data which can be shrunk, if so it does it on
128 a link_order by link_order basis.
129
130 */
131
132 #include "sysdep.h"
133 #include "bfd.h"
134 #include "libbfd.h"
135 #include "bfdlink.h"
136
137 /*
138 DOCDD
139 INODE
140 typedef asection, section prototypes, Section Output, Sections
141 SUBSECTION
142 typedef asection
143
144 Here is the section structure:
145
146 EXTERNAL
147 .{* Linenumber stuff. *}
148 .typedef struct lineno_cache_entry
149 .{
150 . unsigned int line_number; {* Linenumber from start of function. *}
151 . union
152 . {
153 . struct bfd_symbol *sym; {* Function name. *}
154 . bfd_vma offset; {* Offset into section. *}
155 . } u;
156 .}
157 .alent;
158 .
159
160 CODE_FRAGMENT
161 .typedef struct bfd_section
162 .{
163 . {* The name of the section; the name isn't a copy, the pointer is
164 . the same as that passed to bfd_make_section. *}
165 . const char *name;
166 .
167 . {* The next section in the list belonging to the BFD, or NULL. *}
168 . struct bfd_section *next;
169 .
170 . {* The previous section in the list belonging to the BFD, or NULL. *}
171 . struct bfd_section *prev;
172 .
173 . {* A unique sequence number. *}
174 . unsigned int id;
175 .
176 . {* A unique section number which can be used by assembler to
177 . distinguish different sections with the same section name. *}
178 . unsigned int section_id;
179 .
180 . {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *}
181 . unsigned int index;
182 .
183 . {* The field flags contains attributes of the section. Some
184 . flags are read in from the object file, and some are
185 . synthesized from other information. *}
186 . flagword flags;
187 .
188 .#define SEC_NO_FLAGS 0x0
189 .
190 . {* Tells the OS to allocate space for this section when loading.
191 . This is clear for a section containing debug information only. *}
192 .#define SEC_ALLOC 0x1
193 .
194 . {* Tells the OS to load the section from the file when loading.
195 . This is clear for a .bss section. *}
196 .#define SEC_LOAD 0x2
197 .
198 . {* The section contains data still to be relocated, so there is
199 . some relocation information too. *}
200 .#define SEC_RELOC 0x4
201 .
202 . {* A signal to the OS that the section contains read only data. *}
203 .#define SEC_READONLY 0x8
204 .
205 . {* The section contains code only. *}
206 .#define SEC_CODE 0x10
207 .
208 . {* The section contains data only. *}
209 .#define SEC_DATA 0x20
210 .
211 . {* The section will reside in ROM. *}
212 .#define SEC_ROM 0x40
213 .
214 . {* The section contains constructor information. This section
215 . type is used by the linker to create lists of constructors and
216 . destructors used by <<g++>>. When a back end sees a symbol
217 . which should be used in a constructor list, it creates a new
218 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
219 . the symbol to it, and builds a relocation. To build the lists
220 . of constructors, all the linker has to do is catenate all the
221 . sections called <<__CTOR_LIST__>> and relocate the data
222 . contained within - exactly the operations it would peform on
223 . standard data. *}
224 .#define SEC_CONSTRUCTOR 0x80
225 .
226 . {* The section has contents - a data section could be
227 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
228 . <<SEC_HAS_CONTENTS>> *}
229 .#define SEC_HAS_CONTENTS 0x100
230 .
231 . {* An instruction to the linker to not output the section
232 . even if it has information which would normally be written. *}
233 .#define SEC_NEVER_LOAD 0x200
234 .
235 . {* The section contains thread local data. *}
236 .#define SEC_THREAD_LOCAL 0x400
237 .
238 . {* The section's size is fixed. Generic linker code will not
239 . recalculate it and it is up to whoever has set this flag to
240 . get the size right. *}
241 .#define SEC_FIXED_SIZE 0x800
242 .
243 . {* The section contains common symbols (symbols may be defined
244 . multiple times, the value of a symbol is the amount of
245 . space it requires, and the largest symbol value is the one
246 . used). Most targets have exactly one of these (which we
247 . translate to bfd_com_section_ptr), but ECOFF has two. *}
248 .#define SEC_IS_COMMON 0x1000
249 .
250 . {* The section contains only debugging information. For
251 . example, this is set for ELF .debug and .stab sections.
252 . strip tests this flag to see if a section can be
253 . discarded. *}
254 .#define SEC_DEBUGGING 0x2000
255 .
256 . {* The contents of this section are held in memory pointed to
257 . by the contents field. This is checked by bfd_get_section_contents,
258 . and the data is retrieved from memory if appropriate. *}
259 .#define SEC_IN_MEMORY 0x4000
260 .
261 . {* The contents of this section are to be excluded by the
262 . linker for executable and shared objects unless those
263 . objects are to be further relocated. *}
264 .#define SEC_EXCLUDE 0x8000
265 .
266 . {* The contents of this section are to be sorted based on the sum of
267 . the symbol and addend values specified by the associated relocation
268 . entries. Entries without associated relocation entries will be
269 . appended to the end of the section in an unspecified order. *}
270 .#define SEC_SORT_ENTRIES 0x10000
271 .
272 . {* When linking, duplicate sections of the same name should be
273 . discarded, rather than being combined into a single section as
274 . is usually done. This is similar to how common symbols are
275 . handled. See SEC_LINK_DUPLICATES below. *}
276 .#define SEC_LINK_ONCE 0x20000
277 .
278 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
279 . should handle duplicate sections. *}
280 .#define SEC_LINK_DUPLICATES 0xc0000
281 .
282 . {* This value for SEC_LINK_DUPLICATES means that duplicate
283 . sections with the same name should simply be discarded. *}
284 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
285 .
286 . {* This value for SEC_LINK_DUPLICATES means that the linker
287 . should warn if there are any duplicate sections, although
288 . it should still only link one copy. *}
289 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000
290 .
291 . {* This value for SEC_LINK_DUPLICATES means that the linker
292 . should warn if any duplicate sections are a different size. *}
293 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000
294 .
295 . {* This value for SEC_LINK_DUPLICATES means that the linker
296 . should warn if any duplicate sections contain different
297 . contents. *}
298 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS \
299 . (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE)
300 .
301 . {* This section was created by the linker as part of dynamic
302 . relocation or other arcane processing. It is skipped when
303 . going through the first-pass output, trusting that someone
304 . else up the line will take care of it later. *}
305 .#define SEC_LINKER_CREATED 0x100000
306 .
307 . {* This section contains a section ID to distinguish different
308 . sections with the same section name. *}
309 .#define SEC_ASSEMBLER_SECTION_ID 0x100000
310 .
311 . {* This section should not be subject to garbage collection.
312 . Also set to inform the linker that this section should not be
313 . listed in the link map as discarded. *}
314 .#define SEC_KEEP 0x200000
315 .
316 . {* This section contains "short" data, and should be placed
317 . "near" the GP. *}
318 .#define SEC_SMALL_DATA 0x400000
319 .
320 . {* Attempt to merge identical entities in the section.
321 . Entity size is given in the entsize field. *}
322 .#define SEC_MERGE 0x800000
323 .
324 . {* If given with SEC_MERGE, entities to merge are zero terminated
325 . strings where entsize specifies character size instead of fixed
326 . size entries. *}
327 .#define SEC_STRINGS 0x1000000
328 .
329 . {* This section contains data about section groups. *}
330 .#define SEC_GROUP 0x2000000
331 .
332 . {* The section is a COFF shared library section. This flag is
333 . only for the linker. If this type of section appears in
334 . the input file, the linker must copy it to the output file
335 . without changing the vma or size. FIXME: Although this
336 . was originally intended to be general, it really is COFF
337 . specific (and the flag was renamed to indicate this). It
338 . might be cleaner to have some more general mechanism to
339 . allow the back end to control what the linker does with
340 . sections. *}
341 .#define SEC_COFF_SHARED_LIBRARY 0x4000000
342 .
343 . {* This input section should be copied to output in reverse order
344 . as an array of pointers. This is for ELF linker internal use
345 . only. *}
346 .#define SEC_ELF_REVERSE_COPY 0x4000000
347 .
348 . {* This section contains data which may be shared with other
349 . executables or shared objects. This is for COFF only. *}
350 .#define SEC_COFF_SHARED 0x8000000
351 .
352 . {* Indicate that section has the purecode flag set. *}
353 .#define SEC_ELF_PURECODE 0x8000000
354 .
355 . {* When a section with this flag is being linked, then if the size of
356 . the input section is less than a page, it should not cross a page
357 . boundary. If the size of the input section is one page or more,
358 . it should be aligned on a page boundary. This is for TI
359 . TMS320C54X only. *}
360 .#define SEC_TIC54X_BLOCK 0x10000000
361 .
362 . {* This section has the SHF_X86_64_LARGE flag. This is ELF x86-64 only. *}
363 .#define SEC_ELF_LARGE 0x10000000
364 .
365 . {* Conditionally link this section; do not link if there are no
366 . references found to any symbol in the section. This is for TI
367 . TMS320C54X only. *}
368 .#define SEC_TIC54X_CLINK 0x20000000
369 .
370 . {* This section contains vliw code. This is for Toshiba MeP only. *}
371 .#define SEC_MEP_VLIW 0x20000000
372 .
373 . {* All symbols, sizes and relocations in this section are octets
374 . instead of bytes. Required for DWARF debug sections as DWARF
375 . information is organized in octets, not bytes. *}
376 .#define SEC_ELF_OCTETS 0x40000000
377 .
378 . {* Indicate that section has the no read flag set. This happens
379 . when memory read flag isn't set. *}
380 .#define SEC_COFF_NOREAD 0x40000000
381 .
382 . {* End of section flags. *}
383 .
384 . {* Some internal packed boolean fields. *}
385 .
386 . {* See the vma field. *}
387 . unsigned int user_set_vma : 1;
388 .
389 . {* A mark flag used by some of the linker backends. *}
390 . unsigned int linker_mark : 1;
391 .
392 . {* Another mark flag used by some of the linker backends. Set for
393 . output sections that have an input section. *}
394 . unsigned int linker_has_input : 1;
395 .
396 . {* Mark flag used by some linker backends for garbage collection. *}
397 . unsigned int gc_mark : 1;
398 .
399 . {* Section compression status. *}
400 . unsigned int compress_status : 2;
401 .#define COMPRESS_SECTION_NONE 0
402 .#define COMPRESS_SECTION_DONE 1
403 .#define DECOMPRESS_SECTION_ZLIB 2
404 .#define DECOMPRESS_SECTION_ZSTD 3
405 .
406 . {* The following flags are used by the ELF linker. *}
407 .
408 . {* Mark sections which have been allocated to segments. *}
409 . unsigned int segment_mark : 1;
410 .
411 . {* Type of sec_info information. *}
412 . unsigned int sec_info_type:3;
413 .#define SEC_INFO_TYPE_NONE 0
414 .#define SEC_INFO_TYPE_STABS 1
415 .#define SEC_INFO_TYPE_MERGE 2
416 .#define SEC_INFO_TYPE_EH_FRAME 3
417 .#define SEC_INFO_TYPE_JUST_SYMS 4
418 .#define SEC_INFO_TYPE_TARGET 5
419 .#define SEC_INFO_TYPE_EH_FRAME_ENTRY 6
420 .#define SEC_INFO_TYPE_SFRAME 7
421 .
422 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
423 . unsigned int use_rela_p:1;
424 .
425 . {* Nonzero if section contents are mmapped. *}
426 . unsigned int mmapped_p:1;
427 .
428 . {* Nonzero if section contents should not be freed. *}
429 . unsigned int alloced:1;
430 .
431 . {* Bits used by various backends. The generic code doesn't touch
432 . these fields. *}
433 .
434 . unsigned int sec_flg0:1;
435 . unsigned int sec_flg1:1;
436 . unsigned int sec_flg2:1;
437 . unsigned int sec_flg3:1;
438 . unsigned int sec_flg4:1;
439 . unsigned int sec_flg5:1;
440 .
441 . {* End of internal packed boolean fields. *}
442 .
443 . {* The virtual memory address of the section - where it will be
444 . at run time. The symbols are relocated against this. The
445 . user_set_vma flag is maintained by bfd; if it's not set, the
446 . backend can assign addresses (for example, in <<a.out>>, where
447 . the default address for <<.data>> is dependent on the specific
448 . target and various flags). *}
449 . bfd_vma vma;
450 .
451 . {* The load address of the section - where it would be in a
452 . rom image; really only used for writing section header
453 . information. *}
454 . bfd_vma lma;
455 .
456 . {* The size of the section in *octets*, as it will be output.
457 . Contains a value even if the section has no contents (e.g., the
458 . size of <<.bss>>). *}
459 . bfd_size_type size;
460 .
461 . {* For input sections, the original size on disk of the section, in
462 . octets. This field should be set for any section whose size is
463 . changed by linker relaxation. It is required for sections where
464 . the linker relaxation scheme doesn't cache altered section and
465 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
466 . targets), and thus the original size needs to be kept to read the
467 . section multiple times. For output sections, rawsize holds the
468 . section size calculated on a previous linker relaxation pass. *}
469 . bfd_size_type rawsize;
470 .
471 . {* The compressed size of the section in octets. *}
472 . bfd_size_type compressed_size;
473 .
474 . {* If this section is going to be output, then this value is the
475 . offset in *bytes* into the output section of the first byte in the
476 . input section (byte ==> smallest addressable unit on the
477 . target). In most cases, if this was going to start at the
478 . 100th octet (8-bit quantity) in the output section, this value
479 . would be 100. However, if the target byte size is 16 bits
480 . (bfd_octets_per_byte is "2"), this value would be 50. *}
481 . bfd_vma output_offset;
482 .
483 . {* The output section through which to map on output. *}
484 . struct bfd_section *output_section;
485 .
486 . {* If an input section, a pointer to a vector of relocation
487 . records for the data in this section. *}
488 . struct reloc_cache_entry *relocation;
489 .
490 . {* If an output section, a pointer to a vector of pointers to
491 . relocation records for the data in this section. *}
492 . struct reloc_cache_entry **orelocation;
493 .
494 . {* The number of relocation records in one of the above. *}
495 . unsigned reloc_count;
496 .
497 . {* The alignment requirement of the section, as an exponent of 2 -
498 . e.g., 3 aligns to 2^3 (or 8). *}
499 . unsigned int alignment_power;
500 .
501 . {* Information below is back end specific - and not always used
502 . or updated. *}
503 .
504 . {* File position of section data. *}
505 . file_ptr filepos;
506 .
507 . {* File position of relocation info. *}
508 . file_ptr rel_filepos;
509 .
510 . {* File position of line data. *}
511 . file_ptr line_filepos;
512 .
513 . {* Pointer to data for applications. *}
514 . void *userdata;
515 .
516 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
517 . contents. *}
518 . bfd_byte *contents;
519 .
520 . {* Attached line number information. *}
521 . alent *lineno;
522 .
523 . {* Number of line number records. *}
524 . unsigned int lineno_count;
525 .
526 . {* Entity size for merging purposes. *}
527 . unsigned int entsize;
528 .
529 . {* Points to the kept section if this section is a link-once section,
530 . and is discarded. *}
531 . struct bfd_section *kept_section;
532 .
533 . {* When a section is being output, this value changes as more
534 . linenumbers are written out. *}
535 . file_ptr moving_line_filepos;
536 .
537 . {* What the section number is in the target world. *}
538 . int target_index;
539 .
540 . void *used_by_bfd;
541 .
542 . {* If this is a constructor section then here is a list of the
543 . relocations created to relocate items within it. *}
544 . struct relent_chain *constructor_chain;
545 .
546 . {* The BFD which owns the section. *}
547 . bfd *owner;
548 .
549 . {* A symbol which points at this section only. *}
550 . struct bfd_symbol *symbol;
551 .
552 . {* Early in the link process, map_head and map_tail are used to build
553 . a list of input sections attached to an output section. Later,
554 . output sections use these fields for a list of bfd_link_order
555 . structs. The linked_to_symbol_name field is for ELF assembler
556 . internal use. *}
557 . union {
558 . struct bfd_link_order *link_order;
559 . struct bfd_section *s;
560 . const char *linked_to_symbol_name;
561 . } map_head, map_tail;
562 .
563 . {* Points to the output section this section is already assigned to,
564 . if any. This is used when support for non-contiguous memory
565 . regions is enabled. *}
566 . struct bfd_section *already_assigned;
567 .
568 . {* Explicitly specified section type, if non-zero. *}
569 . unsigned int type;
570 .
571 .} asection;
572 .
573
574 EXTERNAL
575 .static inline const char *
576 .bfd_section_name (const asection *sec)
577 .{
578 . return sec->name;
579 .}
580 .
581 .static inline bfd_size_type
582 .bfd_section_size (const asection *sec)
583 .{
584 . return sec->size;
585 .}
586 .
587 .static inline bfd_vma
588 .bfd_section_vma (const asection *sec)
589 .{
590 . return sec->vma;
591 .}
592 .
593 .static inline bfd_vma
594 .bfd_section_lma (const asection *sec)
595 .{
596 . return sec->lma;
597 .}
598 .
599 .static inline unsigned int
600 .bfd_section_alignment (const asection *sec)
601 .{
602 . return sec->alignment_power;
603 .}
604 .
605 .static inline flagword
606 .bfd_section_flags (const asection *sec)
607 .{
608 . return sec->flags;
609 .}
610 .
611 .static inline void *
612 .bfd_section_userdata (const asection *sec)
613 .{
614 . return sec->userdata;
615 .}
616 .static inline bool
617 .bfd_is_com_section (const asection *sec)
618 .{
619 . return (sec->flags & SEC_IS_COMMON) != 0;
620 .}
621 .
622 .{* Note: the following are provided as inline functions rather than macros
623 . because not all callers use the return value. A macro implementation
624 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
625 . compilers will complain about comma expressions that have no effect. *}
626 .static inline bool
627 .bfd_set_section_userdata (asection *sec, void *val)
628 .{
629 . sec->userdata = val;
630 . return true;
631 .}
632 .
633 .static inline bool
634 .bfd_set_section_vma (asection *sec, bfd_vma val)
635 .{
636 . sec->vma = sec->lma = val;
637 . sec->user_set_vma = true;
638 . return true;
639 .}
640 .
641 .static inline bool
642 .bfd_set_section_lma (asection *sec, bfd_vma val)
643 .{
644 . sec->lma = val;
645 . return true;
646 .}
647 .
648 .static inline bool
649 .bfd_set_section_alignment (asection *sec, unsigned int val)
650 .{
651 . if (val >= sizeof (bfd_vma) * 8 - 1)
652 . return false;
653 . sec->alignment_power = val;
654 . return true;
655 .}
656 .
657 .{* These sections are global, and are managed by BFD. The application
658 . and target back end are not permitted to change the values in
659 . these sections. *}
660 .extern asection _bfd_std_section[4];
661 .
662 .#define BFD_ABS_SECTION_NAME "*ABS*"
663 .#define BFD_UND_SECTION_NAME "*UND*"
664 .#define BFD_COM_SECTION_NAME "*COM*"
665 .#define BFD_IND_SECTION_NAME "*IND*"
666 .
667 .{* GNU object-only section name. *}
668 .#define GNU_OBJECT_ONLY_SECTION_NAME ".gnu_object_only"
669 .
670 .{* Pointer to the common section. *}
671 .#define bfd_com_section_ptr (&_bfd_std_section[0])
672 .{* Pointer to the undefined section. *}
673 .#define bfd_und_section_ptr (&_bfd_std_section[1])
674 .{* Pointer to the absolute section. *}
675 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
676 .{* Pointer to the indirect section. *}
677 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
678 .
679 .static inline bool
680 .bfd_is_und_section (const asection *sec)
681 .{
682 . return sec == bfd_und_section_ptr;
683 .}
684 .
685 .static inline bool
686 .bfd_is_abs_section (const asection *sec)
687 .{
688 . return sec == bfd_abs_section_ptr;
689 .}
690 .
691 .static inline bool
692 .bfd_is_ind_section (const asection *sec)
693 .{
694 . return sec == bfd_ind_section_ptr;
695 .}
696 .
697 .static inline bool
698 .bfd_is_const_section (const asection *sec)
699 .{
700 . return (sec >= _bfd_std_section
701 . && sec < _bfd_std_section + (sizeof (_bfd_std_section)
702 . / sizeof (_bfd_std_section[0])));
703 .}
704 .
705 .{* Return TRUE if input section SEC has been discarded. *}
706 .static inline bool
707 .discarded_section (const asection *sec)
708 .{
709 . return (!bfd_is_abs_section (sec)
710 . && bfd_is_abs_section (sec->output_section)
711 . && sec->sec_info_type != SEC_INFO_TYPE_MERGE
712 . && sec->sec_info_type != SEC_INFO_TYPE_JUST_SYMS);
713 .}
714 .
715 INTERNAL
716 .#define BFD_FAKE_SECTION(SEC, SYM, NAME, IDX, FLAGS) \
717 . {* name, next, prev, id, section_id, index, flags, user_set_vma, *} \
718 . { NAME, NULL, NULL, IDX, 0, 0, FLAGS, 0, \
719 . \
720 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
721 . 0, 0, 1, 0, \
722 . \
723 . {* segment_mark, sec_info_type, use_rela_p, mmapped_p, alloced, *} \
724 . 0, 0, 0, 0, 0, \
725 . \
726 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
727 . 0, 0, 0, 0, 0, 0, \
728 . \
729 . {* vma, lma, size, rawsize, compressed_size, *} \
730 . 0, 0, 0, 0, 0, \
731 . \
732 . {* output_offset, output_section, relocation, orelocation, *} \
733 . 0, &SEC, NULL, NULL, \
734 . \
735 . {* reloc_count, alignment_power, filepos, rel_filepos, *} \
736 . 0, 0, 0, 0, \
737 . \
738 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
739 . 0, NULL, NULL, NULL, 0, \
740 . \
741 . {* entsize, kept_section, moving_line_filepos, *} \
742 . 0, NULL, 0, \
743 . \
744 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
745 . 0, NULL, NULL, NULL, \
746 . \
747 . {* symbol, *} \
748 . (struct bfd_symbol *) SYM, \
749 . \
750 . {* map_head, map_tail, already_assigned, type *} \
751 . { NULL }, { NULL }, NULL, 0 \
752 . \
753 . }
754 .
755 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
756 . {* the_bfd, name, value, attr, section, udata *} \
757 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 } }
758 .
759 */
760
761 /* These symbols are global, not specific to any BFD. Therefore, anything
762 that tries to change them is broken, and should be repaired. */
763
764 static const asymbol global_syms[] =
765 {
766 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, bfd_com_section_ptr),
767 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, bfd_und_section_ptr),
768 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, bfd_abs_section_ptr),
769 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, bfd_ind_section_ptr)
770 };
771
772 #define STD_SECTION(NAME, IDX, FLAGS) \
773 BFD_FAKE_SECTION(_bfd_std_section[IDX], &global_syms[IDX], NAME, IDX, FLAGS)
774
775 asection _bfd_std_section[] = {
776 STD_SECTION (BFD_COM_SECTION_NAME, 0, SEC_IS_COMMON),
777 STD_SECTION (BFD_UND_SECTION_NAME, 1, 0),
778 STD_SECTION (BFD_ABS_SECTION_NAME, 2, 0),
779 STD_SECTION (BFD_IND_SECTION_NAME, 3, 0)
780 };
781 #undef STD_SECTION
782
783 /* Initialize an entry in the section hash table. */
784
785 struct bfd_hash_entry *
786 bfd_section_hash_newfunc (struct bfd_hash_entry *entry,
787 struct bfd_hash_table *table,
788 const char *string)
789 {
790 /* Allocate the structure if it has not already been allocated by a
791 subclass. */
792 if (entry == NULL)
793 {
794 entry = (struct bfd_hash_entry *)
795 bfd_hash_allocate (table, sizeof (struct section_hash_entry));
796 if (entry == NULL)
797 return entry;
798 }
799
800 /* Call the allocation method of the superclass. */
801 entry = bfd_hash_newfunc (entry, table, string);
802 if (entry != NULL)
803 memset (&((struct section_hash_entry *) entry)->section, 0,
804 sizeof (asection));
805
806 return entry;
807 }
808
809 #define section_hash_lookup(table, string, create, copy) \
810 ((struct section_hash_entry *) \
811 bfd_hash_lookup ((table), (string), (create), (copy)))
812
813 /* Create a symbol whose only job is to point to this section. This
814 is useful for things like relocs which are relative to the base
815 of a section. */
816
817 bool
818 _bfd_generic_new_section_hook (bfd *abfd, asection *newsect)
819 {
820 newsect->symbol = bfd_make_empty_symbol (abfd);
821 if (newsect->symbol == NULL)
822 return false;
823
824 newsect->symbol->name = newsect->name;
825 newsect->symbol->value = 0;
826 newsect->symbol->section = newsect;
827 newsect->symbol->flags = BSF_SECTION_SYM;
828
829 return true;
830 }
831
832 unsigned int _bfd_section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
833
834 /* Initializes a new section. NEWSECT->NAME is already set. */
835
836 static asection *
837 bfd_section_init (bfd *abfd, asection *newsect)
838 {
839 /* Locking needed for the _bfd_section_id access. */
840 if (!bfd_lock ())
841 return NULL;
842
843 newsect->id = _bfd_section_id;
844 newsect->index = abfd->section_count;
845 newsect->owner = abfd;
846
847 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
848 return NULL;
849
850 _bfd_section_id++;
851 abfd->section_count++;
852 bfd_section_list_append (abfd, newsect);
853
854 if (!bfd_unlock ())
855 return NULL;
856
857 return newsect;
858 }
859
860 /*
861 DOCDD
862 INODE
863 section prototypes, , typedef asection, Sections
864 SUBSECTION
865 Section prototypes
866
867 These are the functions exported by the section handling part of BFD.
868 */
869
870 /*
871 FUNCTION
872 bfd_section_list_clear
873
874 SYNOPSIS
875 void bfd_section_list_clear (bfd *);
876
877 DESCRIPTION
878 Clears the section list, and also resets the section count and
879 hash table entries.
880 */
881
882 void
883 bfd_section_list_clear (bfd *abfd)
884 {
885 abfd->sections = NULL;
886 abfd->section_last = NULL;
887 abfd->section_count = 0;
888 memset (abfd->section_htab.table, 0,
889 abfd->section_htab.size * sizeof (struct bfd_hash_entry *));
890 abfd->section_htab.count = 0;
891 }
892
893 /*
894 FUNCTION
895 bfd_get_section_by_name
896
897 SYNOPSIS
898 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
899
900 DESCRIPTION
901 Return the most recently created section attached to @var{abfd}
902 named @var{name}. Return NULL if no such section exists.
903 */
904
905 asection *
906 bfd_get_section_by_name (bfd *abfd, const char *name)
907 {
908 struct section_hash_entry *sh;
909
910 if (name == NULL)
911 return NULL;
912
913 sh = section_hash_lookup (&abfd->section_htab, name, false, false);
914 if (sh != NULL)
915 return &sh->section;
916
917 return NULL;
918 }
919
920 /*
921 FUNCTION
922 bfd_get_next_section_by_name
923
924 SYNOPSIS
925 asection *bfd_get_next_section_by_name (bfd *ibfd, asection *sec);
926
927 DESCRIPTION
928 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
929 return the next most recently created section attached to the same
930 BFD with the same name, or if no such section exists in the same BFD and
931 IBFD is non-NULL, the next section with the same name in any input
932 BFD following IBFD. Return NULL on finding no section.
933 */
934
935 asection *
936 bfd_get_next_section_by_name (bfd *ibfd, asection *sec)
937 {
938 struct section_hash_entry *sh;
939 const char *name;
940 unsigned long hash;
941
942 sh = ((struct section_hash_entry *)
943 ((char *) sec - offsetof (struct section_hash_entry, section)));
944
945 hash = sh->root.hash;
946 name = sec->name;
947 for (sh = (struct section_hash_entry *) sh->root.next;
948 sh != NULL;
949 sh = (struct section_hash_entry *) sh->root.next)
950 if (sh->root.hash == hash
951 && strcmp (sh->root.string, name) == 0)
952 return &sh->section;
953
954 if (ibfd != NULL)
955 {
956 while ((ibfd = ibfd->link.next) != NULL)
957 {
958 asection *s = bfd_get_section_by_name (ibfd, name);
959 if (s != NULL)
960 return s;
961 }
962 }
963
964 return NULL;
965 }
966
967 /*
968 FUNCTION
969 bfd_get_linker_section
970
971 SYNOPSIS
972 asection *bfd_get_linker_section (bfd *abfd, const char *name);
973
974 DESCRIPTION
975 Return the linker created section attached to @var{abfd}
976 named @var{name}. Return NULL if no such section exists.
977 */
978
979 asection *
980 bfd_get_linker_section (bfd *abfd, const char *name)
981 {
982 asection *sec = bfd_get_section_by_name (abfd, name);
983
984 while (sec != NULL && (sec->flags & SEC_LINKER_CREATED) == 0)
985 sec = bfd_get_next_section_by_name (NULL, sec);
986 return sec;
987 }
988
989 /*
990 FUNCTION
991 bfd_get_section_by_name_if
992
993 SYNOPSIS
994 asection *bfd_get_section_by_name_if
995 (bfd *abfd,
996 const char *name,
997 bool (*func) (bfd *abfd, asection *sect, void *obj),
998 void *obj);
999
1000 DESCRIPTION
1001 Call the provided function @var{func} for each section
1002 attached to the BFD @var{abfd} whose name matches @var{name},
1003 passing @var{obj} as an argument. The function will be called
1004 as if by
1005
1006 | func (abfd, the_section, obj);
1007
1008 It returns the first section for which @var{func} returns true,
1009 otherwise <<NULL>>.
1010
1011 */
1012
1013 asection *
1014 bfd_get_section_by_name_if (bfd *abfd, const char *name,
1015 bool (*operation) (bfd *, asection *, void *),
1016 void *user_storage)
1017 {
1018 struct section_hash_entry *sh;
1019 unsigned long hash;
1020
1021 if (name == NULL)
1022 return NULL;
1023
1024 sh = section_hash_lookup (&abfd->section_htab, name, false, false);
1025 if (sh == NULL)
1026 return NULL;
1027
1028 hash = sh->root.hash;
1029 for (; sh != NULL; sh = (struct section_hash_entry *) sh->root.next)
1030 if (sh->root.hash == hash
1031 && strcmp (sh->root.string, name) == 0
1032 && (*operation) (abfd, &sh->section, user_storage))
1033 return &sh->section;
1034
1035 return NULL;
1036 }
1037
1038 /*
1039 FUNCTION
1040 bfd_get_unique_section_name
1041
1042 SYNOPSIS
1043 char *bfd_get_unique_section_name
1044 (bfd *abfd, const char *templat, int *count);
1045
1046 DESCRIPTION
1047 Invent a section name that is unique in @var{abfd} by tacking
1048 a dot and a digit suffix onto the original @var{templat}. If
1049 @var{count} is non-NULL, then it specifies the first number
1050 tried as a suffix to generate a unique name. The value
1051 pointed to by @var{count} will be incremented in this case.
1052 */
1053
1054 char *
1055 bfd_get_unique_section_name (bfd *abfd, const char *templat, int *count)
1056 {
1057 int num;
1058 unsigned int len;
1059 char *sname;
1060
1061 len = strlen (templat);
1062 sname = bfd_alloc (abfd, len + 8);
1063 if (sname == NULL)
1064 return NULL;
1065 memcpy (sname, templat, len);
1066 num = 1;
1067 if (count != NULL)
1068 num = *count;
1069
1070 do
1071 {
1072 /* If we have a million sections, something is badly wrong. */
1073 if (num > 999999)
1074 abort ();
1075 sprintf (sname + len, ".%d", num++);
1076 }
1077 while (section_hash_lookup (&abfd->section_htab, sname, false, false));
1078
1079 if (count != NULL)
1080 *count = num;
1081 return sname;
1082 }
1083
1084 /*
1085 FUNCTION
1086 bfd_make_section_old_way
1087
1088 SYNOPSIS
1089 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1090
1091 DESCRIPTION
1092 Create a new empty section called @var{name}
1093 and attach it to the end of the chain of sections for the
1094 BFD @var{abfd}. An attempt to create a section with a name which
1095 is already in use returns its pointer without changing the
1096 section chain.
1097
1098 It has the funny name since this is the way it used to be
1099 before it was rewritten....
1100
1101 Possible errors are:
1102 o <<bfd_error_invalid_operation>> -
1103 If output has already started for this BFD.
1104 o <<bfd_error_no_memory>> -
1105 If memory allocation fails.
1106
1107 */
1108
1109 asection *
1110 bfd_make_section_old_way (bfd *abfd, const char *name)
1111 {
1112 asection *newsect;
1113
1114 if (abfd->output_has_begun)
1115 {
1116 bfd_set_error (bfd_error_invalid_operation);
1117 return NULL;
1118 }
1119
1120 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
1121 newsect = bfd_abs_section_ptr;
1122 else if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
1123 newsect = bfd_com_section_ptr;
1124 else if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
1125 newsect = bfd_und_section_ptr;
1126 else if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
1127 newsect = bfd_ind_section_ptr;
1128 else
1129 {
1130 struct section_hash_entry *sh;
1131
1132 sh = section_hash_lookup (&abfd->section_htab, name, true, false);
1133 if (sh == NULL)
1134 return NULL;
1135
1136 newsect = &sh->section;
1137 if (newsect->name != NULL)
1138 {
1139 /* Section already exists. */
1140 return newsect;
1141 }
1142
1143 newsect->name = name;
1144 return bfd_section_init (abfd, newsect);
1145 }
1146
1147 return newsect;
1148 }
1149
1150 /*
1151 FUNCTION
1152 bfd_make_section_anyway_with_flags
1153
1154 SYNOPSIS
1155 asection *bfd_make_section_anyway_with_flags
1156 (bfd *abfd, const char *name, flagword flags);
1157
1158 DESCRIPTION
1159 Create a new empty section called @var{name} and attach it to the end of
1160 the chain of sections for @var{abfd}. Create a new section even if there
1161 is already a section with that name. Also set the attributes of the
1162 new section to the value @var{flags}.
1163
1164 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1165 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1166 o <<bfd_error_no_memory>> - If memory allocation fails.
1167 */
1168
1169 sec_ptr
1170 bfd_make_section_anyway_with_flags (bfd *abfd, const char *name,
1171 flagword flags)
1172 {
1173 struct section_hash_entry *sh;
1174 asection *newsect;
1175
1176 if (abfd->output_has_begun)
1177 {
1178 bfd_set_error (bfd_error_invalid_operation);
1179 return NULL;
1180 }
1181
1182 sh = section_hash_lookup (&abfd->section_htab, name, true, false);
1183 if (sh == NULL)
1184 return NULL;
1185
1186 newsect = &sh->section;
1187 if (newsect->name != NULL)
1188 {
1189 /* We are making a section of the same name. Put it in the
1190 section hash table. Even though we can't find it directly by a
1191 hash lookup, we'll be able to find the section by traversing
1192 sh->root.next quicker than looking at all the bfd sections. */
1193 struct section_hash_entry *new_sh;
1194 new_sh = (struct section_hash_entry *)
1195 bfd_section_hash_newfunc (NULL, &abfd->section_htab, name);
1196 if (new_sh == NULL)
1197 return NULL;
1198
1199 new_sh->root = sh->root;
1200 sh->root.next = &new_sh->root;
1201 newsect = &new_sh->section;
1202 }
1203
1204 newsect->flags = flags;
1205 newsect->name = name;
1206 return bfd_section_init (abfd, newsect);
1207 }
1208
1209 /*
1210 FUNCTION
1211 bfd_make_section_anyway
1212
1213 SYNOPSIS
1214 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1215
1216 DESCRIPTION
1217 Create a new empty section called @var{name} and attach it to the end of
1218 the chain of sections for @var{abfd}. Create a new section even if there
1219 is already a section with that name.
1220
1221 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1222 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1223 o <<bfd_error_no_memory>> - If memory allocation fails.
1224 */
1225
1226 sec_ptr
1227 bfd_make_section_anyway (bfd *abfd, const char *name)
1228 {
1229 return bfd_make_section_anyway_with_flags (abfd, name, 0);
1230 }
1231
1232 /*
1233 FUNCTION
1234 bfd_make_section_with_flags
1235
1236 SYNOPSIS
1237 asection *bfd_make_section_with_flags
1238 (bfd *, const char *name, flagword flags);
1239
1240 DESCRIPTION
1241 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1242 bfd_set_error ()) without changing the section chain if there is already a
1243 section named @var{name}. Also set the attributes of the new section to
1244 the value @var{flags}. If there is an error, return <<NULL>> and set
1245 <<bfd_error>>.
1246 */
1247
1248 asection *
1249 bfd_make_section_with_flags (bfd *abfd, const char *name,
1250 flagword flags)
1251 {
1252 struct section_hash_entry *sh;
1253 asection *newsect;
1254
1255 if (abfd == NULL || name == NULL || abfd->output_has_begun)
1256 {
1257 bfd_set_error (bfd_error_invalid_operation);
1258 return NULL;
1259 }
1260
1261 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0
1262 || strcmp (name, BFD_COM_SECTION_NAME) == 0
1263 || strcmp (name, BFD_UND_SECTION_NAME) == 0
1264 || strcmp (name, BFD_IND_SECTION_NAME) == 0)
1265 return NULL;
1266
1267 sh = section_hash_lookup (&abfd->section_htab, name, true, false);
1268 if (sh == NULL)
1269 return NULL;
1270
1271 newsect = &sh->section;
1272 if (newsect->name != NULL)
1273 {
1274 /* Section already exists. */
1275 return NULL;
1276 }
1277
1278 newsect->name = name;
1279 newsect->flags = flags;
1280 return bfd_section_init (abfd, newsect);
1281 }
1282
1283 /*
1284 FUNCTION
1285 bfd_make_section
1286
1287 SYNOPSIS
1288 asection *bfd_make_section (bfd *, const char *name);
1289
1290 DESCRIPTION
1291 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1292 bfd_set_error ()) without changing the section chain if there is already a
1293 section named @var{name}. If there is an error, return <<NULL>> and set
1294 <<bfd_error>>.
1295 */
1296
1297 asection *
1298 bfd_make_section (bfd *abfd, const char *name)
1299 {
1300 return bfd_make_section_with_flags (abfd, name, 0);
1301 }
1302
1303 /*
1304 FUNCTION
1305 bfd_set_section_flags
1306
1307 SYNOPSIS
1308 bool bfd_set_section_flags (asection *sec, flagword flags);
1309
1310 DESCRIPTION
1311 Set the attributes of the section @var{sec} to the value @var{flags}.
1312 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1313 returns are:
1314
1315 o <<bfd_error_invalid_operation>> -
1316 The section cannot have one or more of the attributes
1317 requested. For example, a .bss section in <<a.out>> may not
1318 have the <<SEC_HAS_CONTENTS>> field set.
1319
1320 */
1321
1322 bool
1323 bfd_set_section_flags (asection *section, flagword flags)
1324 {
1325 section->flags = flags;
1326 return true;
1327 }
1328
1329 /*
1330 FUNCTION
1331 bfd_rename_section
1332
1333 SYNOPSIS
1334 void bfd_rename_section
1335 (asection *sec, const char *newname);
1336
1337 DESCRIPTION
1338 Rename section @var{sec} to @var{newname}.
1339 */
1340
1341 void
1342 bfd_rename_section (asection *sec, const char *newname)
1343 {
1344 struct section_hash_entry *sh;
1345
1346 sh = (struct section_hash_entry *)
1347 ((char *) sec - offsetof (struct section_hash_entry, section));
1348 sh->section.name = newname;
1349 bfd_hash_rename (&sec->owner->section_htab, newname, &sh->root);
1350 }
1351
1352 /*
1353 FUNCTION
1354 bfd_map_over_sections
1355
1356 SYNOPSIS
1357 void bfd_map_over_sections
1358 (bfd *abfd,
1359 void (*func) (bfd *abfd, asection *sect, void *obj),
1360 void *obj);
1361
1362 DESCRIPTION
1363 Call the provided function @var{func} for each section
1364 attached to the BFD @var{abfd}, passing @var{obj} as an
1365 argument. The function will be called as if by
1366
1367 | func (abfd, the_section, obj);
1368
1369 This is the preferred method for iterating over sections; an
1370 alternative would be to use a loop:
1371
1372 | asection *p;
1373 | for (p = abfd->sections; p != NULL; p = p->next)
1374 | func (abfd, p, ...)
1375
1376 */
1377
1378 void
1379 bfd_map_over_sections (bfd *abfd,
1380 void (*operation) (bfd *, asection *, void *),
1381 void *user_storage)
1382 {
1383 asection *sect;
1384 unsigned int i = 0;
1385
1386 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
1387 (*operation) (abfd, sect, user_storage);
1388
1389 if (i != abfd->section_count) /* Debugging */
1390 abort ();
1391 }
1392
1393 /*
1394 FUNCTION
1395 bfd_sections_find_if
1396
1397 SYNOPSIS
1398 asection *bfd_sections_find_if
1399 (bfd *abfd,
1400 bool (*operation) (bfd *abfd, asection *sect, void *obj),
1401 void *obj);
1402
1403 DESCRIPTION
1404 Call the provided function @var{operation} for each section
1405 attached to the BFD @var{abfd}, passing @var{obj} as an
1406 argument. The function will be called as if by
1407
1408 | operation (abfd, the_section, obj);
1409
1410 It returns the first section for which @var{operation} returns true.
1411
1412 */
1413
1414 asection *
1415 bfd_sections_find_if (bfd *abfd,
1416 bool (*operation) (bfd *, asection *, void *),
1417 void *user_storage)
1418 {
1419 asection *sect;
1420
1421 for (sect = abfd->sections; sect != NULL; sect = sect->next)
1422 if ((*operation) (abfd, sect, user_storage))
1423 break;
1424
1425 return sect;
1426 }
1427
1428 /*
1429 FUNCTION
1430 bfd_set_section_size
1431
1432 SYNOPSIS
1433 bool bfd_set_section_size (asection *sec, bfd_size_type val);
1434
1435 DESCRIPTION
1436 Set @var{sec} to the size @var{val}. If the operation is
1437 ok, then <<TRUE>> is returned, else <<FALSE>>.
1438
1439 Possible error returns:
1440 o <<bfd_error_invalid_operation>> -
1441 Writing has started to the BFD, so setting the size is invalid.
1442
1443 */
1444
1445 bool
1446 bfd_set_section_size (asection *sec, bfd_size_type val)
1447 {
1448 /* Once you've started writing to any section you cannot create or change
1449 the size of any others. */
1450
1451 if (sec->owner == NULL || sec->owner->output_has_begun)
1452 {
1453 bfd_set_error (bfd_error_invalid_operation);
1454 return false;
1455 }
1456
1457 sec->size = val;
1458 return true;
1459 }
1460
1461 /*
1462 FUNCTION
1463 bfd_set_section_contents
1464
1465 SYNOPSIS
1466 bool bfd_set_section_contents
1467 (bfd *abfd, asection *section, const void *data,
1468 file_ptr offset, bfd_size_type count);
1469
1470 DESCRIPTION
1471 Sets the contents of the section @var{section} in BFD
1472 @var{abfd} to the data starting in memory at @var{location}.
1473 The data is written to the output section starting at offset
1474 @var{offset} for @var{count} octets.
1475
1476 Normally <<TRUE>> is returned, but <<FALSE>> is returned if
1477 there was an error. Possible error returns are:
1478 o <<bfd_error_no_contents>> -
1479 The output section does not have the <<SEC_HAS_CONTENTS>>
1480 attribute, so nothing can be written to it.
1481 o <<bfd_error_bad_value>> -
1482 The section is unable to contain all of the data.
1483 o <<bfd_error_invalid_operation>> -
1484 The BFD is not writeable.
1485 o and some more too.
1486
1487 This routine is front end to the back end function
1488 <<_bfd_set_section_contents>>.
1489
1490 */
1491
1492 bool
1493 bfd_set_section_contents (bfd *abfd,
1494 sec_ptr section,
1495 const void *location,
1496 file_ptr offset,
1497 bfd_size_type count)
1498 {
1499 bfd_size_type sz;
1500
1501 if (!(bfd_section_flags (section) & SEC_HAS_CONTENTS))
1502 {
1503 bfd_set_error (bfd_error_no_contents);
1504 return false;
1505 }
1506
1507 sz = section->size;
1508 if ((bfd_size_type) offset > sz
1509 || count > sz - offset
1510 || count != (size_t) count)
1511 {
1512 bfd_set_error (bfd_error_bad_value);
1513 return false;
1514 }
1515
1516 if (!bfd_write_p (abfd))
1517 {
1518 bfd_set_error (bfd_error_invalid_operation);
1519 return false;
1520 }
1521
1522 /* Record a copy of the data in memory if desired. */
1523 if (section->contents
1524 && location != section->contents + offset)
1525 memcpy (section->contents + offset, location, (size_t) count);
1526
1527 if (BFD_SEND (abfd, _bfd_set_section_contents,
1528 (abfd, section, location, offset, count)))
1529 {
1530 abfd->output_has_begun = true;
1531 return true;
1532 }
1533
1534 return false;
1535 }
1536
1537 /*
1538 FUNCTION
1539 bfd_get_section_contents
1540
1541 SYNOPSIS
1542 bool bfd_get_section_contents
1543 (bfd *abfd, asection *section, void *location, file_ptr offset,
1544 bfd_size_type count);
1545
1546 DESCRIPTION
1547 Read data from @var{section} in BFD @var{abfd}
1548 into memory starting at @var{location}. The data is read at an
1549 offset of @var{offset} from the start of the input section,
1550 and is read for @var{count} bytes.
1551
1552 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1553 flag set are requested or if the section does not have the
1554 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1555 with zeroes. If no errors occur, <<TRUE>> is returned, else
1556 <<FALSE>>.
1557
1558 */
1559 bool
1560 bfd_get_section_contents (bfd *abfd,
1561 sec_ptr section,
1562 void *location,
1563 file_ptr offset,
1564 bfd_size_type count)
1565 {
1566 bfd_size_type sz;
1567
1568 if (count == 0)
1569 /* Don't bother. */
1570 return true;
1571
1572 if (section == NULL)
1573 {
1574 bfd_set_error (bfd_error_bad_value);
1575 return false;
1576 }
1577
1578 if (location == NULL)
1579 {
1580 if (section->mmapped_p)
1581 {
1582 /* Pass this request straight on to the target's function.
1583 All of the code below assumes that location != NULL.
1584 FIXME: Should we still check that count is sane ? */
1585 return BFD_SEND (abfd, _bfd_get_section_contents,
1586 (abfd, section, location, offset, count));
1587 }
1588
1589 bfd_set_error (bfd_error_bad_value);
1590 return false;
1591 }
1592
1593 if (section->flags & SEC_CONSTRUCTOR)
1594 {
1595 memset (location, 0, (size_t) count);
1596 return true;
1597 }
1598
1599 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1600 {
1601 memset (location, 0, (size_t) count);
1602 return true;
1603 }
1604
1605 if (abfd == NULL)
1606 return false;
1607
1608 sz = bfd_get_section_limit_octets (abfd, section);
1609 if ((bfd_size_type) offset > sz
1610 || count > sz - offset
1611 || count != (size_t) count)
1612 {
1613 bfd_set_error (bfd_error_bad_value);
1614 return false;
1615 }
1616
1617 if ((section->flags & SEC_IN_MEMORY) != 0)
1618 {
1619 if (section->contents == NULL)
1620 {
1621 /* This can happen because of errors earlier on in the linking process.
1622 We do not want to seg-fault here, so clear the flag and return an
1623 error code. */
1624 section->flags &= ~ SEC_IN_MEMORY;
1625 bfd_set_error (bfd_error_invalid_operation);
1626 return false;
1627 }
1628
1629 memmove (location, section->contents + offset, (size_t) count);
1630 return true;
1631 }
1632
1633 return BFD_SEND (abfd, _bfd_get_section_contents,
1634 (abfd, section, location, offset, count));
1635 }
1636
1637 /*
1638 FUNCTION
1639 bfd_malloc_and_get_section
1640
1641 SYNOPSIS
1642 bool bfd_malloc_and_get_section
1643 (bfd *abfd, asection *section, bfd_byte **buf);
1644
1645 DESCRIPTION
1646 Read all data from @var{section} in BFD @var{abfd}
1647 into a buffer, *@var{buf}, malloc'd by this function.
1648 Return @code{true} on success, @code{false} on failure in which
1649 case *@var{buf} will be NULL.
1650 */
1651
1652 bool
1653 bfd_malloc_and_get_section (bfd *abfd, sec_ptr sec, bfd_byte **buf)
1654 {
1655 /* FIXME: We sometimes get here when sec->alloced is set.
1656 arm, aarch64, and xtensa targets all abort on some ld tests
1657 if we also test sec->alloced here. We really should not ever be
1658 mallocing a buffer if we already have an alloced one. */
1659 if (sec->mmapped_p)
1660 abort ();
1661 *buf = NULL;
1662 return bfd_get_full_section_contents (abfd, sec, buf);
1663 }
1664 /*
1665 FUNCTION
1666 bfd_copy_private_section_data
1667
1668 SYNOPSIS
1669 bool bfd_copy_private_section_data
1670 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec,
1671 struct bfd_link_info *link_info);
1672
1673 DESCRIPTION
1674 Copy private section information from @var{isec} in the BFD
1675 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1676 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1677 returns are:
1678
1679 o <<bfd_error_no_memory>> -
1680 Not enough memory exists to create private data for @var{osec}.
1681
1682 .#define bfd_copy_private_section_data(ibfd, isec, obfd, osec, link_info) \
1683 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1684 . (ibfd, isec, obfd, osec, link_info))
1685 */
1686
1687 /*
1688 FUNCTION
1689 bfd_generic_is_group_section
1690
1691 SYNOPSIS
1692 bool bfd_generic_is_group_section (bfd *, const asection *sec);
1693
1694 DESCRIPTION
1695 Returns TRUE if @var{sec} is a member of a group.
1696 */
1697
1698 bool
1699 bfd_generic_is_group_section (bfd *abfd ATTRIBUTE_UNUSED,
1700 const asection *sec ATTRIBUTE_UNUSED)
1701 {
1702 return false;
1703 }
1704
1705 /*
1706 FUNCTION
1707 bfd_generic_group_name
1708
1709 SYNOPSIS
1710 const char *bfd_generic_group_name (bfd *, const asection *sec);
1711
1712 DESCRIPTION
1713 Returns group name if @var{sec} is a member of a group.
1714 */
1715
1716 const char *
1717 bfd_generic_group_name (bfd *abfd ATTRIBUTE_UNUSED,
1718 const asection *sec ATTRIBUTE_UNUSED)
1719 {
1720 return NULL;
1721 }
1722
1723 /*
1724 FUNCTION
1725 bfd_generic_discard_group
1726
1727 SYNOPSIS
1728 bool bfd_generic_discard_group (bfd *abfd, asection *group);
1729
1730 DESCRIPTION
1731 Remove all members of @var{group} from the output.
1732 */
1733
1734 bool
1735 bfd_generic_discard_group (bfd *abfd ATTRIBUTE_UNUSED,
1736 asection *group ATTRIBUTE_UNUSED)
1737 {
1738 return true;
1739 }
1740
1741 bool
1742 _bfd_nowrite_set_section_contents (bfd *abfd,
1743 sec_ptr section ATTRIBUTE_UNUSED,
1744 const void *location ATTRIBUTE_UNUSED,
1745 file_ptr offset ATTRIBUTE_UNUSED,
1746 bfd_size_type count ATTRIBUTE_UNUSED)
1747 {
1748 return _bfd_bool_bfd_false_error (abfd);
1749 }
1750
1751 /*
1752 FUNCTION
1753 bfd_section_size_insane
1754
1755 SYNOPSIS
1756 bool bfd_section_size_insane (bfd *abfd, asection *sec);
1757
1758 DESCRIPTION
1759 Returns true if the given section has a size that indicates
1760 it cannot be read from file. Return false if the size is OK
1761 *or* this function can't say one way or the other.
1762
1763 */
1764
1765 bool
1766 bfd_section_size_insane (bfd *abfd, asection *sec)
1767 {
1768 bfd_size_type size = bfd_get_section_limit_octets (abfd, sec);
1769 if (size == 0)
1770 return false;
1771
1772 if ((bfd_section_flags (sec) & SEC_IN_MEMORY) != 0
1773 /* PR 24753: Linker created sections can be larger than
1774 the file size, eg if they are being used to hold stubs. */
1775 || (bfd_section_flags (sec) & SEC_LINKER_CREATED) != 0
1776 /* PR 24753: Sections which have no content should also be
1777 excluded as they contain no size on disk. */
1778 || (bfd_section_flags (sec) & SEC_HAS_CONTENTS) == 0
1779 /* The MMO file format supports its own special compression
1780 technique, but it uses COMPRESS_SECTION_NONE when loading
1781 a section's contents. */
1782 || bfd_get_flavour (abfd) == bfd_target_mmo_flavour)
1783 return false;
1784
1785 ufile_ptr filesize = bfd_get_file_size (abfd);
1786 if (filesize == 0)
1787 return false;
1788
1789 if (sec->compress_status == DECOMPRESS_SECTION_ZSTD
1790 || sec->compress_status == DECOMPRESS_SECTION_ZLIB)
1791 {
1792 /* PR26946, PR28834: Sanity check compress header uncompressed
1793 size against the original file size, and check that the
1794 compressed section can be read from file. We choose an
1795 arbitrary uncompressed size of 10x the file size, rather than
1796 a compress ratio. The reason being that compiling
1797 "int aaa..a;" with "a" repeated enough times can result in
1798 compression ratios without limit for .debug_str, whereas such
1799 a file will usually also have the enormous symbol
1800 uncompressed in .symtab. */
1801 if (size / 10 > filesize)
1802 {
1803 bfd_set_error (bfd_error_bad_value);
1804 return true;
1805 }
1806 size = sec->compressed_size;
1807 }
1808
1809 if ((ufile_ptr) sec->filepos > filesize || size > filesize - sec->filepos)
1810 {
1811 bfd_set_error (bfd_error_file_truncated);
1812 return true;
1813 }
1814 return false;
1815 }