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1 /* Object file "section" support for the BFD library.
2 Copyright (C) 1990-2022 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 CODE_FRAGMENT
147 .
148 .typedef struct bfd_section
149 .{
150 . {* The name of the section; the name isn't a copy, the pointer is
151 . the same as that passed to bfd_make_section. *}
152 . const char *name;
153 .
154 . {* The next section in the list belonging to the BFD, or NULL. *}
155 . struct bfd_section *next;
156 .
157 . {* The previous section in the list belonging to the BFD, or NULL. *}
158 . struct bfd_section *prev;
159 .
160 . {* A unique sequence number. *}
161 . unsigned int id;
162 .
163 . {* A unique section number which can be used by assembler to
164 . distinguish different sections with the same section name. *}
165 . unsigned int section_id;
166 .
167 . {* Which section in the bfd; 0..n-1 as sections are created in a bfd. *}
168 . unsigned int index;
169 .
170 . {* The field flags contains attributes of the section. Some
171 . flags are read in from the object file, and some are
172 . synthesized from other information. *}
173 . flagword flags;
174 .
175 .#define SEC_NO_FLAGS 0x0
176 .
177 . {* Tells the OS to allocate space for this section when loading.
178 . This is clear for a section containing debug information only. *}
179 .#define SEC_ALLOC 0x1
180 .
181 . {* Tells the OS to load the section from the file when loading.
182 . This is clear for a .bss section. *}
183 .#define SEC_LOAD 0x2
184 .
185 . {* The section contains data still to be relocated, so there is
186 . some relocation information too. *}
187 .#define SEC_RELOC 0x4
188 .
189 . {* A signal to the OS that the section contains read only data. *}
190 .#define SEC_READONLY 0x8
191 .
192 . {* The section contains code only. *}
193 .#define SEC_CODE 0x10
194 .
195 . {* The section contains data only. *}
196 .#define SEC_DATA 0x20
197 .
198 . {* The section will reside in ROM. *}
199 .#define SEC_ROM 0x40
200 .
201 . {* The section contains constructor information. This section
202 . type is used by the linker to create lists of constructors and
203 . destructors used by <<g++>>. When a back end sees a symbol
204 . which should be used in a constructor list, it creates a new
205 . section for the type of name (e.g., <<__CTOR_LIST__>>), attaches
206 . the symbol to it, and builds a relocation. To build the lists
207 . of constructors, all the linker has to do is catenate all the
208 . sections called <<__CTOR_LIST__>> and relocate the data
209 . contained within - exactly the operations it would peform on
210 . standard data. *}
211 .#define SEC_CONSTRUCTOR 0x80
212 .
213 . {* The section has contents - a data section could be
214 . <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>; a debug section could be
215 . <<SEC_HAS_CONTENTS>> *}
216 .#define SEC_HAS_CONTENTS 0x100
217 .
218 . {* An instruction to the linker to not output the section
219 . even if it has information which would normally be written. *}
220 .#define SEC_NEVER_LOAD 0x200
221 .
222 . {* The section contains thread local data. *}
223 .#define SEC_THREAD_LOCAL 0x400
224 .
225 . {* The section's size is fixed. Generic linker code will not
226 . recalculate it and it is up to whoever has set this flag to
227 . get the size right. *}
228 .#define SEC_FIXED_SIZE 0x800
229 .
230 . {* The section contains common symbols (symbols may be defined
231 . multiple times, the value of a symbol is the amount of
232 . space it requires, and the largest symbol value is the one
233 . used). Most targets have exactly one of these (which we
234 . translate to bfd_com_section_ptr), but ECOFF has two. *}
235 .#define SEC_IS_COMMON 0x1000
236 .
237 . {* The section contains only debugging information. For
238 . example, this is set for ELF .debug and .stab sections.
239 . strip tests this flag to see if a section can be
240 . discarded. *}
241 .#define SEC_DEBUGGING 0x2000
242 .
243 . {* The contents of this section are held in memory pointed to
244 . by the contents field. This is checked by bfd_get_section_contents,
245 . and the data is retrieved from memory if appropriate. *}
246 .#define SEC_IN_MEMORY 0x4000
247 .
248 . {* The contents of this section are to be excluded by the
249 . linker for executable and shared objects unless those
250 . objects are to be further relocated. *}
251 .#define SEC_EXCLUDE 0x8000
252 .
253 . {* The contents of this section are to be sorted based on the sum of
254 . the symbol and addend values specified by the associated relocation
255 . entries. Entries without associated relocation entries will be
256 . appended to the end of the section in an unspecified order. *}
257 .#define SEC_SORT_ENTRIES 0x10000
258 .
259 . {* When linking, duplicate sections of the same name should be
260 . discarded, rather than being combined into a single section as
261 . is usually done. This is similar to how common symbols are
262 . handled. See SEC_LINK_DUPLICATES below. *}
263 .#define SEC_LINK_ONCE 0x20000
264 .
265 . {* If SEC_LINK_ONCE is set, this bitfield describes how the linker
266 . should handle duplicate sections. *}
267 .#define SEC_LINK_DUPLICATES 0xc0000
268 .
269 . {* This value for SEC_LINK_DUPLICATES means that duplicate
270 . sections with the same name should simply be discarded. *}
271 .#define SEC_LINK_DUPLICATES_DISCARD 0x0
272 .
273 . {* This value for SEC_LINK_DUPLICATES means that the linker
274 . should warn if there are any duplicate sections, although
275 . it should still only link one copy. *}
276 .#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000
277 .
278 . {* This value for SEC_LINK_DUPLICATES means that the linker
279 . should warn if any duplicate sections are a different size. *}
280 .#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000
281 .
282 . {* This value for SEC_LINK_DUPLICATES means that the linker
283 . should warn if any duplicate sections contain different
284 . contents. *}
285 .#define SEC_LINK_DUPLICATES_SAME_CONTENTS \
286 . (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE)
287 .
288 . {* This section was created by the linker as part of dynamic
289 . relocation or other arcane processing. It is skipped when
290 . going through the first-pass output, trusting that someone
291 . else up the line will take care of it later. *}
292 .#define SEC_LINKER_CREATED 0x100000
293 .
294 . {* This section contains a section ID to distinguish different
295 . sections with the same section name. *}
296 .#define SEC_ASSEMBLER_SECTION_ID 0x100000
297 .
298 . {* This section should not be subject to garbage collection.
299 . Also set to inform the linker that this section should not be
300 . listed in the link map as discarded. *}
301 .#define SEC_KEEP 0x200000
302 .
303 . {* This section contains "short" data, and should be placed
304 . "near" the GP. *}
305 .#define SEC_SMALL_DATA 0x400000
306 .
307 . {* Attempt to merge identical entities in the section.
308 . Entity size is given in the entsize field. *}
309 .#define SEC_MERGE 0x800000
310 .
311 . {* If given with SEC_MERGE, entities to merge are zero terminated
312 . strings where entsize specifies character size instead of fixed
313 . size entries. *}
314 .#define SEC_STRINGS 0x1000000
315 .
316 . {* This section contains data about section groups. *}
317 .#define SEC_GROUP 0x2000000
318 .
319 . {* The section is a COFF shared library section. This flag is
320 . only for the linker. If this type of section appears in
321 . the input file, the linker must copy it to the output file
322 . without changing the vma or size. FIXME: Although this
323 . was originally intended to be general, it really is COFF
324 . specific (and the flag was renamed to indicate this). It
325 . might be cleaner to have some more general mechanism to
326 . allow the back end to control what the linker does with
327 . sections. *}
328 .#define SEC_COFF_SHARED_LIBRARY 0x4000000
329 .
330 . {* This input section should be copied to output in reverse order
331 . as an array of pointers. This is for ELF linker internal use
332 . only. *}
333 .#define SEC_ELF_REVERSE_COPY 0x4000000
334 .
335 . {* This section contains data which may be shared with other
336 . executables or shared objects. This is for COFF only. *}
337 .#define SEC_COFF_SHARED 0x8000000
338 .
339 . {* This section should be compressed. This is for ELF linker
340 . internal use only. *}
341 .#define SEC_ELF_COMPRESS 0x8000000
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,
346 . it should be aligned on a page boundary. This is for TI
347 . TMS320C54X only. *}
348 .#define SEC_TIC54X_BLOCK 0x10000000
349 .
350 . {* This section should be renamed. This is for ELF linker
351 . internal use only. *}
352 .#define SEC_ELF_RENAME 0x10000000
353 .
354 . {* Conditionally link this section; do not link if there are no
355 . references found to any symbol in the section. This is for TI
356 . TMS320C54X only. *}
357 .#define SEC_TIC54X_CLINK 0x20000000
358 .
359 . {* This section contains vliw code. This is for Toshiba MeP only. *}
360 .#define SEC_MEP_VLIW 0x20000000
361 .
362 . {* All symbols, sizes and relocations in this section are octets
363 . instead of bytes. Required for DWARF debug sections as DWARF
364 . information is organized in octets, not bytes. *}
365 .#define SEC_ELF_OCTETS 0x40000000
366 .
367 . {* Indicate that section has the no read flag set. This happens
368 . when memory read flag isn't set. *}
369 .#define SEC_COFF_NOREAD 0x40000000
370 .
371 . {* Indicate that section has the purecode flag set. *}
372 .#define SEC_ELF_PURECODE 0x80000000
373 .
374 . {* End of section flags. *}
375 .
376 . {* Some internal packed boolean fields. *}
377 .
378 . {* See the vma field. *}
379 . unsigned int user_set_vma : 1;
380 .
381 . {* A mark flag used by some of the linker backends. *}
382 . unsigned int linker_mark : 1;
383 .
384 . {* Another mark flag used by some of the linker backends. Set for
385 . output sections that have an input section. *}
386 . unsigned int linker_has_input : 1;
387 .
388 . {* Mark flag used by some linker backends for garbage collection. *}
389 . unsigned int gc_mark : 1;
390 .
391 . {* Section compression status. *}
392 . unsigned int compress_status : 2;
393 .#define COMPRESS_SECTION_NONE 0
394 .#define COMPRESS_SECTION_DONE 1
395 .#define DECOMPRESS_SECTION_ZLIB 2
396 .#define DECOMPRESS_SECTION_ZSTD 3
397 .
398 . {* The following flags are used by the ELF linker. *}
399 .
400 . {* Mark sections which have been allocated to segments. *}
401 . unsigned int segment_mark : 1;
402 .
403 . {* Type of sec_info information. *}
404 . unsigned int sec_info_type:3;
405 .#define SEC_INFO_TYPE_NONE 0
406 .#define SEC_INFO_TYPE_STABS 1
407 .#define SEC_INFO_TYPE_MERGE 2
408 .#define SEC_INFO_TYPE_EH_FRAME 3
409 .#define SEC_INFO_TYPE_JUST_SYMS 4
410 .#define SEC_INFO_TYPE_TARGET 5
411 .#define SEC_INFO_TYPE_EH_FRAME_ENTRY 6
412 .#define SEC_INFO_TYPE_SFRAME 7
413 .
414 . {* Nonzero if this section uses RELA relocations, rather than REL. *}
415 . unsigned int use_rela_p:1;
416 .
417 . {* Bits used by various backends. The generic code doesn't touch
418 . these fields. *}
419 .
420 . unsigned int sec_flg0:1;
421 . unsigned int sec_flg1:1;
422 . unsigned int sec_flg2:1;
423 . unsigned int sec_flg3:1;
424 . unsigned int sec_flg4:1;
425 . unsigned int sec_flg5:1;
426 .
427 . {* End of internal packed boolean fields. *}
428 .
429 . {* The virtual memory address of the section - where it will be
430 . at run time. The symbols are relocated against this. The
431 . user_set_vma flag is maintained by bfd; if it's not set, the
432 . backend can assign addresses (for example, in <<a.out>>, where
433 . the default address for <<.data>> is dependent on the specific
434 . target and various flags). *}
435 . bfd_vma vma;
436 .
437 . {* The load address of the section - where it would be in a
438 . rom image; really only used for writing section header
439 . information. *}
440 . bfd_vma lma;
441 .
442 . {* The size of the section in *octets*, as it will be output.
443 . Contains a value even if the section has no contents (e.g., the
444 . size of <<.bss>>). *}
445 . bfd_size_type size;
446 .
447 . {* For input sections, the original size on disk of the section, in
448 . octets. This field should be set for any section whose size is
449 . changed by linker relaxation. It is required for sections where
450 . the linker relaxation scheme doesn't cache altered section and
451 . reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing
452 . targets), and thus the original size needs to be kept to read the
453 . section multiple times. For output sections, rawsize holds the
454 . section size calculated on a previous linker relaxation pass. *}
455 . bfd_size_type rawsize;
456 .
457 . {* The compressed size of the section in octets. *}
458 . bfd_size_type compressed_size;
459 .
460 . {* If this section is going to be output, then this value is the
461 . offset in *bytes* into the output section of the first byte in the
462 . input section (byte ==> smallest addressable unit on the
463 . target). In most cases, if this was going to start at the
464 . 100th octet (8-bit quantity) in the output section, this value
465 . would be 100. However, if the target byte size is 16 bits
466 . (bfd_octets_per_byte is "2"), this value would be 50. *}
467 . bfd_vma output_offset;
468 .
469 . {* The output section through which to map on output. *}
470 . struct bfd_section *output_section;
471 .
472 . {* If an input section, a pointer to a vector of relocation
473 . records for the data in this section. *}
474 . struct reloc_cache_entry *relocation;
475 .
476 . {* If an output section, a pointer to a vector of pointers to
477 . relocation records for the data in this section. *}
478 . struct reloc_cache_entry **orelocation;
479 .
480 . {* The number of relocation records in one of the above. *}
481 . unsigned reloc_count;
482 .
483 . {* The alignment requirement of the section, as an exponent of 2 -
484 . e.g., 3 aligns to 2^3 (or 8). *}
485 . unsigned int alignment_power;
486 .
487 . {* Information below is back end specific - and not always used
488 . or updated. *}
489 .
490 . {* File position of section data. *}
491 . file_ptr filepos;
492 .
493 . {* File position of relocation info. *}
494 . file_ptr rel_filepos;
495 .
496 . {* File position of line data. *}
497 . file_ptr line_filepos;
498 .
499 . {* Pointer to data for applications. *}
500 . void *userdata;
501 .
502 . {* If the SEC_IN_MEMORY flag is set, this points to the actual
503 . contents. *}
504 . unsigned char *contents;
505 .
506 . {* Attached line number information. *}
507 . alent *lineno;
508 .
509 . {* Number of line number records. *}
510 . unsigned int lineno_count;
511 .
512 . {* Entity size for merging purposes. *}
513 . unsigned int entsize;
514 .
515 . {* Points to the kept section if this section is a link-once section,
516 . and is discarded. *}
517 . struct bfd_section *kept_section;
518 .
519 . {* When a section is being output, this value changes as more
520 . linenumbers are written out. *}
521 . file_ptr moving_line_filepos;
522 .
523 . {* What the section number is in the target world. *}
524 . int target_index;
525 .
526 . void *used_by_bfd;
527 .
528 . {* If this is a constructor section then here is a list of the
529 . relocations created to relocate items within it. *}
530 . struct relent_chain *constructor_chain;
531 .
532 . {* The BFD which owns the section. *}
533 . bfd *owner;
534 .
535 . {* A symbol which points at this section only. *}
536 . struct bfd_symbol *symbol;
537 . struct bfd_symbol **symbol_ptr_ptr;
538 .
539 . {* Early in the link process, map_head and map_tail are used to build
540 . a list of input sections attached to an output section. Later,
541 . output sections use these fields for a list of bfd_link_order
542 . structs. The linked_to_symbol_name field is for ELF assembler
543 . internal use. *}
544 . union {
545 . struct bfd_link_order *link_order;
546 . struct bfd_section *s;
547 . const char *linked_to_symbol_name;
548 . } map_head, map_tail;
549 .
550 . {* Points to the output section this section is already assigned to,
551 . if any. This is used when support for non-contiguous memory
552 . regions is enabled. *}
553 . struct bfd_section *already_assigned;
554 .
555 . {* Explicitly specified section type, if non-zero. *}
556 . unsigned int type;
557 .
558 .} asection;
559 .
560 .static inline const char *
561 .bfd_section_name (const asection *sec)
562 .{
563 . return sec->name;
564 .}
565 .
566 .static inline bfd_size_type
567 .bfd_section_size (const asection *sec)
568 .{
569 . return sec->size;
570 .}
571 .
572 .static inline bfd_vma
573 .bfd_section_vma (const asection *sec)
574 .{
575 . return sec->vma;
576 .}
577 .
578 .static inline bfd_vma
579 .bfd_section_lma (const asection *sec)
580 .{
581 . return sec->lma;
582 .}
583 .
584 .static inline unsigned int
585 .bfd_section_alignment (const asection *sec)
586 .{
587 . return sec->alignment_power;
588 .}
589 .
590 .static inline flagword
591 .bfd_section_flags (const asection *sec)
592 .{
593 . return sec->flags;
594 .}
595 .
596 .static inline void *
597 .bfd_section_userdata (const asection *sec)
598 .{
599 . return sec->userdata;
600 .}
601 .static inline bool
602 .bfd_is_com_section (const asection *sec)
603 .{
604 . return (sec->flags & SEC_IS_COMMON) != 0;
605 .}
606 .
607 .{* Note: the following are provided as inline functions rather than macros
608 . because not all callers use the return value. A macro implementation
609 . would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some
610 . compilers will complain about comma expressions that have no effect. *}
611 .static inline bool
612 .bfd_set_section_userdata (asection *sec, void *val)
613 .{
614 . sec->userdata = val;
615 . return true;
616 .}
617 .
618 .static inline bool
619 .bfd_set_section_vma (asection *sec, bfd_vma val)
620 .{
621 . sec->vma = sec->lma = val;
622 . sec->user_set_vma = true;
623 . return true;
624 .}
625 .
626 .static inline bool
627 .bfd_set_section_lma (asection *sec, bfd_vma val)
628 .{
629 . sec->lma = val;
630 . return true;
631 .}
632 .
633 .static inline bool
634 .bfd_set_section_alignment (asection *sec, unsigned int val)
635 .{
636 . if (val >= sizeof (bfd_vma) * 8 - 1)
637 . return false;
638 . sec->alignment_power = val;
639 . return true;
640 .}
641 .
642 .{* These sections are global, and are managed by BFD. The application
643 . and target back end are not permitted to change the values in
644 . these sections. *}
645 .extern asection _bfd_std_section[4];
646 .
647 .#define BFD_ABS_SECTION_NAME "*ABS*"
648 .#define BFD_UND_SECTION_NAME "*UND*"
649 .#define BFD_COM_SECTION_NAME "*COM*"
650 .#define BFD_IND_SECTION_NAME "*IND*"
651 .
652 .{* Pointer to the common section. *}
653 .#define bfd_com_section_ptr (&_bfd_std_section[0])
654 .{* Pointer to the undefined section. *}
655 .#define bfd_und_section_ptr (&_bfd_std_section[1])
656 .{* Pointer to the absolute section. *}
657 .#define bfd_abs_section_ptr (&_bfd_std_section[2])
658 .{* Pointer to the indirect section. *}
659 .#define bfd_ind_section_ptr (&_bfd_std_section[3])
660 .
661 .static inline bool
662 .bfd_is_und_section (const asection *sec)
663 .{
664 . return sec == bfd_und_section_ptr;
665 .}
666 .
667 .static inline bool
668 .bfd_is_abs_section (const asection *sec)
669 .{
670 . return sec == bfd_abs_section_ptr;
671 .}
672 .
673 .static inline bool
674 .bfd_is_ind_section (const asection *sec)
675 .{
676 . return sec == bfd_ind_section_ptr;
677 .}
678 .
679 .static inline bool
680 .bfd_is_const_section (const asection *sec)
681 .{
682 . return (sec >= _bfd_std_section
683 . && sec < _bfd_std_section + (sizeof (_bfd_std_section)
684 . / sizeof (_bfd_std_section[0])));
685 .}
686 .
687 .{* Return TRUE if input section SEC has been discarded. *}
688 .static inline bool
689 .discarded_section (const asection *sec)
690 .{
691 . return (!bfd_is_abs_section (sec)
692 . && bfd_is_abs_section (sec->output_section)
693 . && sec->sec_info_type != SEC_INFO_TYPE_MERGE
694 . && sec->sec_info_type != SEC_INFO_TYPE_JUST_SYMS);
695 .}
696 .
697 .#define BFD_FAKE_SECTION(SEC, SYM, NAME, IDX, FLAGS) \
698 . {* name, next, prev, id, section_id, index, flags, user_set_vma, *} \
699 . { NAME, NULL, NULL, IDX, 0, 0, FLAGS, 0, \
700 . \
701 . {* linker_mark, linker_has_input, gc_mark, decompress_status, *} \
702 . 0, 0, 1, 0, \
703 . \
704 . {* segment_mark, sec_info_type, use_rela_p, *} \
705 . 0, 0, 0, \
706 . \
707 . {* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, *} \
708 . 0, 0, 0, 0, 0, 0, \
709 . \
710 . {* vma, lma, size, rawsize, compressed_size, *} \
711 . 0, 0, 0, 0, 0, \
712 . \
713 . {* output_offset, output_section, relocation, orelocation, *} \
714 . 0, &SEC, NULL, NULL, \
715 . \
716 . {* reloc_count, alignment_power, filepos, rel_filepos, *} \
717 . 0, 0, 0, 0, \
718 . \
719 . {* line_filepos, userdata, contents, lineno, lineno_count, *} \
720 . 0, NULL, NULL, NULL, 0, \
721 . \
722 . {* entsize, kept_section, moving_line_filepos, *} \
723 . 0, NULL, 0, \
724 . \
725 . {* target_index, used_by_bfd, constructor_chain, owner, *} \
726 . 0, NULL, NULL, NULL, \
727 . \
728 . {* symbol, symbol_ptr_ptr, *} \
729 . (struct bfd_symbol *) SYM, &SEC.symbol, \
730 . \
731 . {* map_head, map_tail, already_assigned, type *} \
732 . { NULL }, { NULL }, NULL, 0 \
733 . \
734 . }
735 .
736 .{* We use a macro to initialize the static asymbol structures because
737 . traditional C does not permit us to initialize a union member while
738 . gcc warns if we don't initialize it.
739 . the_bfd, name, value, attr, section [, udata] *}
740 .#ifdef __STDC__
741 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
742 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION, { 0 }}
743 .#else
744 .#define GLOBAL_SYM_INIT(NAME, SECTION) \
745 . { 0, NAME, 0, BSF_SECTION_SYM, SECTION }
746 .#endif
747 .
748 */
749
750 /* These symbols are global, not specific to any BFD. Therefore, anything
751 that tries to change them is broken, and should be repaired. */
752
753 static const asymbol global_syms[] =
754 {
755 GLOBAL_SYM_INIT (BFD_COM_SECTION_NAME, bfd_com_section_ptr),
756 GLOBAL_SYM_INIT (BFD_UND_SECTION_NAME, bfd_und_section_ptr),
757 GLOBAL_SYM_INIT (BFD_ABS_SECTION_NAME, bfd_abs_section_ptr),
758 GLOBAL_SYM_INIT (BFD_IND_SECTION_NAME, bfd_ind_section_ptr)
759 };
760
761 #define STD_SECTION(NAME, IDX, FLAGS) \
762 BFD_FAKE_SECTION(_bfd_std_section[IDX], &global_syms[IDX], NAME, IDX, FLAGS)
763
764 asection _bfd_std_section[] = {
765 STD_SECTION (BFD_COM_SECTION_NAME, 0, SEC_IS_COMMON),
766 STD_SECTION (BFD_UND_SECTION_NAME, 1, 0),
767 STD_SECTION (BFD_ABS_SECTION_NAME, 2, 0),
768 STD_SECTION (BFD_IND_SECTION_NAME, 3, 0)
769 };
770 #undef STD_SECTION
771
772 /* Initialize an entry in the section hash table. */
773
774 struct bfd_hash_entry *
775 bfd_section_hash_newfunc (struct bfd_hash_entry *entry,
776 struct bfd_hash_table *table,
777 const char *string)
778 {
779 /* Allocate the structure if it has not already been allocated by a
780 subclass. */
781 if (entry == NULL)
782 {
783 entry = (struct bfd_hash_entry *)
784 bfd_hash_allocate (table, sizeof (struct section_hash_entry));
785 if (entry == NULL)
786 return entry;
787 }
788
789 /* Call the allocation method of the superclass. */
790 entry = bfd_hash_newfunc (entry, table, string);
791 if (entry != NULL)
792 memset (&((struct section_hash_entry *) entry)->section, 0,
793 sizeof (asection));
794
795 return entry;
796 }
797
798 #define section_hash_lookup(table, string, create, copy) \
799 ((struct section_hash_entry *) \
800 bfd_hash_lookup ((table), (string), (create), (copy)))
801
802 /* Create a symbol whose only job is to point to this section. This
803 is useful for things like relocs which are relative to the base
804 of a section. */
805
806 bool
807 _bfd_generic_new_section_hook (bfd *abfd, asection *newsect)
808 {
809 newsect->symbol = bfd_make_empty_symbol (abfd);
810 if (newsect->symbol == NULL)
811 return false;
812
813 newsect->symbol->name = newsect->name;
814 newsect->symbol->value = 0;
815 newsect->symbol->section = newsect;
816 newsect->symbol->flags = BSF_SECTION_SYM;
817
818 newsect->symbol_ptr_ptr = &newsect->symbol;
819 return true;
820 }
821
822 unsigned int _bfd_section_id = 0x10; /* id 0 to 3 used by STD_SECTION. */
823
824 /* Initializes a new section. NEWSECT->NAME is already set. */
825
826 static asection *
827 bfd_section_init (bfd *abfd, asection *newsect)
828 {
829 newsect->id = _bfd_section_id;
830 newsect->index = abfd->section_count;
831 newsect->owner = abfd;
832
833 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
834 return NULL;
835
836 _bfd_section_id++;
837 abfd->section_count++;
838 bfd_section_list_append (abfd, newsect);
839 return newsect;
840 }
841
842 /*
843 DOCDD
844 INODE
845 section prototypes, , typedef asection, Sections
846 SUBSECTION
847 Section prototypes
848
849 These are the functions exported by the section handling part of BFD.
850 */
851
852 /*
853 FUNCTION
854 bfd_section_list_clear
855
856 SYNOPSIS
857 void bfd_section_list_clear (bfd *);
858
859 DESCRIPTION
860 Clears the section list, and also resets the section count and
861 hash table entries.
862 */
863
864 void
865 bfd_section_list_clear (bfd *abfd)
866 {
867 abfd->sections = NULL;
868 abfd->section_last = NULL;
869 abfd->section_count = 0;
870 memset (abfd->section_htab.table, 0,
871 abfd->section_htab.size * sizeof (struct bfd_hash_entry *));
872 abfd->section_htab.count = 0;
873 }
874
875 /*
876 FUNCTION
877 bfd_get_section_by_name
878
879 SYNOPSIS
880 asection *bfd_get_section_by_name (bfd *abfd, const char *name);
881
882 DESCRIPTION
883 Return the most recently created section attached to @var{abfd}
884 named @var{name}. Return NULL if no such section exists.
885 */
886
887 asection *
888 bfd_get_section_by_name (bfd *abfd, const char *name)
889 {
890 struct section_hash_entry *sh;
891
892 if (name == NULL)
893 return NULL;
894
895 sh = section_hash_lookup (&abfd->section_htab, name, false, false);
896 if (sh != NULL)
897 return &sh->section;
898
899 return NULL;
900 }
901
902 /*
903 FUNCTION
904 bfd_get_next_section_by_name
905
906 SYNOPSIS
907 asection *bfd_get_next_section_by_name (bfd *ibfd, asection *sec);
908
909 DESCRIPTION
910 Given @var{sec} is a section returned by @code{bfd_get_section_by_name},
911 return the next most recently created section attached to the same
912 BFD with the same name, or if no such section exists in the same BFD and
913 IBFD is non-NULL, the next section with the same name in any input
914 BFD following IBFD. Return NULL on finding no section.
915 */
916
917 asection *
918 bfd_get_next_section_by_name (bfd *ibfd, asection *sec)
919 {
920 struct section_hash_entry *sh;
921 const char *name;
922 unsigned long hash;
923
924 sh = ((struct section_hash_entry *)
925 ((char *) sec - offsetof (struct section_hash_entry, section)));
926
927 hash = sh->root.hash;
928 name = sec->name;
929 for (sh = (struct section_hash_entry *) sh->root.next;
930 sh != NULL;
931 sh = (struct section_hash_entry *) sh->root.next)
932 if (sh->root.hash == hash
933 && strcmp (sh->root.string, name) == 0)
934 return &sh->section;
935
936 if (ibfd != NULL)
937 {
938 while ((ibfd = ibfd->link.next) != NULL)
939 {
940 asection *s = bfd_get_section_by_name (ibfd, name);
941 if (s != NULL)
942 return s;
943 }
944 }
945
946 return NULL;
947 }
948
949 /*
950 FUNCTION
951 bfd_get_linker_section
952
953 SYNOPSIS
954 asection *bfd_get_linker_section (bfd *abfd, const char *name);
955
956 DESCRIPTION
957 Return the linker created section attached to @var{abfd}
958 named @var{name}. Return NULL if no such section exists.
959 */
960
961 asection *
962 bfd_get_linker_section (bfd *abfd, const char *name)
963 {
964 asection *sec = bfd_get_section_by_name (abfd, name);
965
966 while (sec != NULL && (sec->flags & SEC_LINKER_CREATED) == 0)
967 sec = bfd_get_next_section_by_name (NULL, sec);
968 return sec;
969 }
970
971 /*
972 FUNCTION
973 bfd_get_section_by_name_if
974
975 SYNOPSIS
976 asection *bfd_get_section_by_name_if
977 (bfd *abfd,
978 const char *name,
979 bool (*func) (bfd *abfd, asection *sect, void *obj),
980 void *obj);
981
982 DESCRIPTION
983 Call the provided function @var{func} for each section
984 attached to the BFD @var{abfd} whose name matches @var{name},
985 passing @var{obj} as an argument. The function will be called
986 as if by
987
988 | func (abfd, the_section, obj);
989
990 It returns the first section for which @var{func} returns true,
991 otherwise <<NULL>>.
992
993 */
994
995 asection *
996 bfd_get_section_by_name_if (bfd *abfd, const char *name,
997 bool (*operation) (bfd *, asection *, void *),
998 void *user_storage)
999 {
1000 struct section_hash_entry *sh;
1001 unsigned long hash;
1002
1003 if (name == NULL)
1004 return NULL;
1005
1006 sh = section_hash_lookup (&abfd->section_htab, name, false, false);
1007 if (sh == NULL)
1008 return NULL;
1009
1010 hash = sh->root.hash;
1011 for (; sh != NULL; sh = (struct section_hash_entry *) sh->root.next)
1012 if (sh->root.hash == hash
1013 && strcmp (sh->root.string, name) == 0
1014 && (*operation) (abfd, &sh->section, user_storage))
1015 return &sh->section;
1016
1017 return NULL;
1018 }
1019
1020 /*
1021 FUNCTION
1022 bfd_get_unique_section_name
1023
1024 SYNOPSIS
1025 char *bfd_get_unique_section_name
1026 (bfd *abfd, const char *templat, int *count);
1027
1028 DESCRIPTION
1029 Invent a section name that is unique in @var{abfd} by tacking
1030 a dot and a digit suffix onto the original @var{templat}. If
1031 @var{count} is non-NULL, then it specifies the first number
1032 tried as a suffix to generate a unique name. The value
1033 pointed to by @var{count} will be incremented in this case.
1034 */
1035
1036 char *
1037 bfd_get_unique_section_name (bfd *abfd, const char *templat, int *count)
1038 {
1039 int num;
1040 unsigned int len;
1041 char *sname;
1042
1043 len = strlen (templat);
1044 sname = (char *) bfd_malloc (len + 8);
1045 if (sname == NULL)
1046 return NULL;
1047 memcpy (sname, templat, len);
1048 num = 1;
1049 if (count != NULL)
1050 num = *count;
1051
1052 do
1053 {
1054 /* If we have a million sections, something is badly wrong. */
1055 if (num > 999999)
1056 abort ();
1057 sprintf (sname + len, ".%d", num++);
1058 }
1059 while (section_hash_lookup (&abfd->section_htab, sname, false, false));
1060
1061 if (count != NULL)
1062 *count = num;
1063 return sname;
1064 }
1065
1066 /*
1067 FUNCTION
1068 bfd_make_section_old_way
1069
1070 SYNOPSIS
1071 asection *bfd_make_section_old_way (bfd *abfd, const char *name);
1072
1073 DESCRIPTION
1074 Create a new empty section called @var{name}
1075 and attach it to the end of the chain of sections for the
1076 BFD @var{abfd}. An attempt to create a section with a name which
1077 is already in use returns its pointer without changing the
1078 section chain.
1079
1080 It has the funny name since this is the way it used to be
1081 before it was rewritten....
1082
1083 Possible errors are:
1084 o <<bfd_error_invalid_operation>> -
1085 If output has already started for this BFD.
1086 o <<bfd_error_no_memory>> -
1087 If memory allocation fails.
1088
1089 */
1090
1091 asection *
1092 bfd_make_section_old_way (bfd *abfd, const char *name)
1093 {
1094 asection *newsect;
1095
1096 if (abfd->output_has_begun)
1097 {
1098 bfd_set_error (bfd_error_invalid_operation);
1099 return NULL;
1100 }
1101
1102 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0)
1103 newsect = bfd_abs_section_ptr;
1104 else if (strcmp (name, BFD_COM_SECTION_NAME) == 0)
1105 newsect = bfd_com_section_ptr;
1106 else if (strcmp (name, BFD_UND_SECTION_NAME) == 0)
1107 newsect = bfd_und_section_ptr;
1108 else if (strcmp (name, BFD_IND_SECTION_NAME) == 0)
1109 newsect = bfd_ind_section_ptr;
1110 else
1111 {
1112 struct section_hash_entry *sh;
1113
1114 sh = section_hash_lookup (&abfd->section_htab, name, true, false);
1115 if (sh == NULL)
1116 return NULL;
1117
1118 newsect = &sh->section;
1119 if (newsect->name != NULL)
1120 {
1121 /* Section already exists. */
1122 return newsect;
1123 }
1124
1125 newsect->name = name;
1126 return bfd_section_init (abfd, newsect);
1127 }
1128
1129 /* Call new_section_hook when "creating" the standard abs, com, und
1130 and ind sections to tack on format specific section data.
1131 Also, create a proper section symbol. */
1132 if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
1133 return NULL;
1134 return newsect;
1135 }
1136
1137 /*
1138 FUNCTION
1139 bfd_make_section_anyway_with_flags
1140
1141 SYNOPSIS
1142 asection *bfd_make_section_anyway_with_flags
1143 (bfd *abfd, const char *name, flagword flags);
1144
1145 DESCRIPTION
1146 Create a new empty section called @var{name} and attach it to the end of
1147 the chain of sections for @var{abfd}. Create a new section even if there
1148 is already a section with that name. Also set the attributes of the
1149 new section to the value @var{flags}.
1150
1151 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1152 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1153 o <<bfd_error_no_memory>> - If memory allocation fails.
1154 */
1155
1156 sec_ptr
1157 bfd_make_section_anyway_with_flags (bfd *abfd, const char *name,
1158 flagword flags)
1159 {
1160 struct section_hash_entry *sh;
1161 asection *newsect;
1162
1163 if (abfd->output_has_begun)
1164 {
1165 bfd_set_error (bfd_error_invalid_operation);
1166 return NULL;
1167 }
1168
1169 sh = section_hash_lookup (&abfd->section_htab, name, true, false);
1170 if (sh == NULL)
1171 return NULL;
1172
1173 newsect = &sh->section;
1174 if (newsect->name != NULL)
1175 {
1176 /* We are making a section of the same name. Put it in the
1177 section hash table. Even though we can't find it directly by a
1178 hash lookup, we'll be able to find the section by traversing
1179 sh->root.next quicker than looking at all the bfd sections. */
1180 struct section_hash_entry *new_sh;
1181 new_sh = (struct section_hash_entry *)
1182 bfd_section_hash_newfunc (NULL, &abfd->section_htab, name);
1183 if (new_sh == NULL)
1184 return NULL;
1185
1186 new_sh->root = sh->root;
1187 sh->root.next = &new_sh->root;
1188 newsect = &new_sh->section;
1189 }
1190
1191 newsect->flags = flags;
1192 newsect->name = name;
1193 return bfd_section_init (abfd, newsect);
1194 }
1195
1196 /*
1197 FUNCTION
1198 bfd_make_section_anyway
1199
1200 SYNOPSIS
1201 asection *bfd_make_section_anyway (bfd *abfd, const char *name);
1202
1203 DESCRIPTION
1204 Create a new empty section called @var{name} and attach it to the end of
1205 the chain of sections for @var{abfd}. Create a new section even if there
1206 is already a section with that name.
1207
1208 Return <<NULL>> and set <<bfd_error>> on error; possible errors are:
1209 o <<bfd_error_invalid_operation>> - If output has already started for @var{abfd}.
1210 o <<bfd_error_no_memory>> - If memory allocation fails.
1211 */
1212
1213 sec_ptr
1214 bfd_make_section_anyway (bfd *abfd, const char *name)
1215 {
1216 return bfd_make_section_anyway_with_flags (abfd, name, 0);
1217 }
1218
1219 /*
1220 FUNCTION
1221 bfd_make_section_with_flags
1222
1223 SYNOPSIS
1224 asection *bfd_make_section_with_flags
1225 (bfd *, const char *name, flagword flags);
1226
1227 DESCRIPTION
1228 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1229 bfd_set_error ()) without changing the section chain if there is already a
1230 section named @var{name}. Also set the attributes of the new section to
1231 the value @var{flags}. If there is an error, return <<NULL>> and set
1232 <<bfd_error>>.
1233 */
1234
1235 asection *
1236 bfd_make_section_with_flags (bfd *abfd, const char *name,
1237 flagword flags)
1238 {
1239 struct section_hash_entry *sh;
1240 asection *newsect;
1241
1242 if (abfd == NULL || name == NULL || abfd->output_has_begun)
1243 {
1244 bfd_set_error (bfd_error_invalid_operation);
1245 return NULL;
1246 }
1247
1248 if (strcmp (name, BFD_ABS_SECTION_NAME) == 0
1249 || strcmp (name, BFD_COM_SECTION_NAME) == 0
1250 || strcmp (name, BFD_UND_SECTION_NAME) == 0
1251 || strcmp (name, BFD_IND_SECTION_NAME) == 0)
1252 return NULL;
1253
1254 sh = section_hash_lookup (&abfd->section_htab, name, true, false);
1255 if (sh == NULL)
1256 return NULL;
1257
1258 newsect = &sh->section;
1259 if (newsect->name != NULL)
1260 {
1261 /* Section already exists. */
1262 return NULL;
1263 }
1264
1265 newsect->name = name;
1266 newsect->flags = flags;
1267 return bfd_section_init (abfd, newsect);
1268 }
1269
1270 /*
1271 FUNCTION
1272 bfd_make_section
1273
1274 SYNOPSIS
1275 asection *bfd_make_section (bfd *, const char *name);
1276
1277 DESCRIPTION
1278 Like <<bfd_make_section_anyway>>, but return <<NULL>> (without calling
1279 bfd_set_error ()) without changing the section chain if there is already a
1280 section named @var{name}. If there is an error, return <<NULL>> and set
1281 <<bfd_error>>.
1282 */
1283
1284 asection *
1285 bfd_make_section (bfd *abfd, const char *name)
1286 {
1287 return bfd_make_section_with_flags (abfd, name, 0);
1288 }
1289
1290 /*
1291 FUNCTION
1292 bfd_set_section_flags
1293
1294 SYNOPSIS
1295 bool bfd_set_section_flags (asection *sec, flagword flags);
1296
1297 DESCRIPTION
1298 Set the attributes of the section @var{sec} to the value @var{flags}.
1299 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1300 returns are:
1301
1302 o <<bfd_error_invalid_operation>> -
1303 The section cannot have one or more of the attributes
1304 requested. For example, a .bss section in <<a.out>> may not
1305 have the <<SEC_HAS_CONTENTS>> field set.
1306
1307 */
1308
1309 bool
1310 bfd_set_section_flags (asection *section, flagword flags)
1311 {
1312 section->flags = flags;
1313 return true;
1314 }
1315
1316 /*
1317 FUNCTION
1318 bfd_rename_section
1319
1320 SYNOPSIS
1321 void bfd_rename_section
1322 (asection *sec, const char *newname);
1323
1324 DESCRIPTION
1325 Rename section @var{sec} to @var{newname}.
1326 */
1327
1328 void
1329 bfd_rename_section (asection *sec, const char *newname)
1330 {
1331 struct section_hash_entry *sh;
1332
1333 sh = (struct section_hash_entry *)
1334 ((char *) sec - offsetof (struct section_hash_entry, section));
1335 sh->section.name = newname;
1336 bfd_hash_rename (&sec->owner->section_htab, newname, &sh->root);
1337 }
1338
1339 /*
1340 FUNCTION
1341 bfd_map_over_sections
1342
1343 SYNOPSIS
1344 void bfd_map_over_sections
1345 (bfd *abfd,
1346 void (*func) (bfd *abfd, asection *sect, void *obj),
1347 void *obj);
1348
1349 DESCRIPTION
1350 Call the provided function @var{func} for each section
1351 attached to the BFD @var{abfd}, passing @var{obj} as an
1352 argument. The function will be called as if by
1353
1354 | func (abfd, the_section, obj);
1355
1356 This is the preferred method for iterating over sections; an
1357 alternative would be to use a loop:
1358
1359 | asection *p;
1360 | for (p = abfd->sections; p != NULL; p = p->next)
1361 | func (abfd, p, ...)
1362
1363 */
1364
1365 void
1366 bfd_map_over_sections (bfd *abfd,
1367 void (*operation) (bfd *, asection *, void *),
1368 void *user_storage)
1369 {
1370 asection *sect;
1371 unsigned int i = 0;
1372
1373 for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
1374 (*operation) (abfd, sect, user_storage);
1375
1376 if (i != abfd->section_count) /* Debugging */
1377 abort ();
1378 }
1379
1380 /*
1381 FUNCTION
1382 bfd_sections_find_if
1383
1384 SYNOPSIS
1385 asection *bfd_sections_find_if
1386 (bfd *abfd,
1387 bool (*operation) (bfd *abfd, asection *sect, void *obj),
1388 void *obj);
1389
1390 DESCRIPTION
1391 Call the provided function @var{operation} for each section
1392 attached to the BFD @var{abfd}, passing @var{obj} as an
1393 argument. The function will be called as if by
1394
1395 | operation (abfd, the_section, obj);
1396
1397 It returns the first section for which @var{operation} returns true.
1398
1399 */
1400
1401 asection *
1402 bfd_sections_find_if (bfd *abfd,
1403 bool (*operation) (bfd *, asection *, void *),
1404 void *user_storage)
1405 {
1406 asection *sect;
1407
1408 for (sect = abfd->sections; sect != NULL; sect = sect->next)
1409 if ((*operation) (abfd, sect, user_storage))
1410 break;
1411
1412 return sect;
1413 }
1414
1415 /*
1416 FUNCTION
1417 bfd_set_section_size
1418
1419 SYNOPSIS
1420 bool bfd_set_section_size (asection *sec, bfd_size_type val);
1421
1422 DESCRIPTION
1423 Set @var{sec} to the size @var{val}. If the operation is
1424 ok, then <<TRUE>> is returned, else <<FALSE>>.
1425
1426 Possible error returns:
1427 o <<bfd_error_invalid_operation>> -
1428 Writing has started to the BFD, so setting the size is invalid.
1429
1430 */
1431
1432 bool
1433 bfd_set_section_size (asection *sec, bfd_size_type val)
1434 {
1435 /* Once you've started writing to any section you cannot create or change
1436 the size of any others. */
1437
1438 if (sec->owner == NULL || sec->owner->output_has_begun)
1439 {
1440 bfd_set_error (bfd_error_invalid_operation);
1441 return false;
1442 }
1443
1444 sec->size = val;
1445 return true;
1446 }
1447
1448 /*
1449 FUNCTION
1450 bfd_set_section_contents
1451
1452 SYNOPSIS
1453 bool bfd_set_section_contents
1454 (bfd *abfd, asection *section, const void *data,
1455 file_ptr offset, bfd_size_type count);
1456
1457 DESCRIPTION
1458 Sets the contents of the section @var{section} in BFD
1459 @var{abfd} to the data starting in memory at @var{location}.
1460 The data is written to the output section starting at offset
1461 @var{offset} for @var{count} octets.
1462
1463 Normally <<TRUE>> is returned, but <<FALSE>> is returned if
1464 there was an error. Possible error returns are:
1465 o <<bfd_error_no_contents>> -
1466 The output section does not have the <<SEC_HAS_CONTENTS>>
1467 attribute, so nothing can be written to it.
1468 o <<bfd_error_bad_value>> -
1469 The section is unable to contain all of the data.
1470 o <<bfd_error_invalid_operation>> -
1471 The BFD is not writeable.
1472 o and some more too.
1473
1474 This routine is front end to the back end function
1475 <<_bfd_set_section_contents>>.
1476
1477 */
1478
1479 bool
1480 bfd_set_section_contents (bfd *abfd,
1481 sec_ptr section,
1482 const void *location,
1483 file_ptr offset,
1484 bfd_size_type count)
1485 {
1486 bfd_size_type sz;
1487
1488 if (!(bfd_section_flags (section) & SEC_HAS_CONTENTS))
1489 {
1490 bfd_set_error (bfd_error_no_contents);
1491 return false;
1492 }
1493
1494 sz = section->size;
1495 if ((bfd_size_type) offset > sz
1496 || count > sz - offset
1497 || count != (size_t) count)
1498 {
1499 bfd_set_error (bfd_error_bad_value);
1500 return false;
1501 }
1502
1503 if (!bfd_write_p (abfd))
1504 {
1505 bfd_set_error (bfd_error_invalid_operation);
1506 return false;
1507 }
1508
1509 /* Record a copy of the data in memory if desired. */
1510 if (section->contents
1511 && location != section->contents + offset)
1512 memcpy (section->contents + offset, location, (size_t) count);
1513
1514 if (BFD_SEND (abfd, _bfd_set_section_contents,
1515 (abfd, section, location, offset, count)))
1516 {
1517 abfd->output_has_begun = true;
1518 return true;
1519 }
1520
1521 return false;
1522 }
1523
1524 /*
1525 FUNCTION
1526 bfd_get_section_contents
1527
1528 SYNOPSIS
1529 bool bfd_get_section_contents
1530 (bfd *abfd, asection *section, void *location, file_ptr offset,
1531 bfd_size_type count);
1532
1533 DESCRIPTION
1534 Read data from @var{section} in BFD @var{abfd}
1535 into memory starting at @var{location}. The data is read at an
1536 offset of @var{offset} from the start of the input section,
1537 and is read for @var{count} bytes.
1538
1539 If the contents of a constructor with the <<SEC_CONSTRUCTOR>>
1540 flag set are requested or if the section does not have the
1541 <<SEC_HAS_CONTENTS>> flag set, then the @var{location} is filled
1542 with zeroes. If no errors occur, <<TRUE>> is returned, else
1543 <<FALSE>>.
1544
1545 */
1546 bool
1547 bfd_get_section_contents (bfd *abfd,
1548 sec_ptr section,
1549 void *location,
1550 file_ptr offset,
1551 bfd_size_type count)
1552 {
1553 bfd_size_type sz;
1554
1555 if (section->flags & SEC_CONSTRUCTOR)
1556 {
1557 memset (location, 0, (size_t) count);
1558 return true;
1559 }
1560
1561 if (abfd->direction != write_direction && section->rawsize != 0)
1562 sz = section->rawsize;
1563 else
1564 sz = section->size;
1565 if ((bfd_size_type) offset > sz
1566 || count > sz - offset
1567 || count != (size_t) count)
1568 {
1569 bfd_set_error (bfd_error_bad_value);
1570 return false;
1571 }
1572
1573 if (count == 0)
1574 /* Don't bother. */
1575 return true;
1576
1577 if ((section->flags & SEC_HAS_CONTENTS) == 0)
1578 {
1579 memset (location, 0, (size_t) count);
1580 return true;
1581 }
1582
1583 if ((section->flags & SEC_IN_MEMORY) != 0)
1584 {
1585 if (section->contents == NULL)
1586 {
1587 /* This can happen because of errors earlier on in the linking process.
1588 We do not want to seg-fault here, so clear the flag and return an
1589 error code. */
1590 section->flags &= ~ SEC_IN_MEMORY;
1591 bfd_set_error (bfd_error_invalid_operation);
1592 return false;
1593 }
1594
1595 memmove (location, section->contents + offset, (size_t) count);
1596 return true;
1597 }
1598
1599 return BFD_SEND (abfd, _bfd_get_section_contents,
1600 (abfd, section, location, offset, count));
1601 }
1602
1603 /*
1604 FUNCTION
1605 bfd_malloc_and_get_section
1606
1607 SYNOPSIS
1608 bool bfd_malloc_and_get_section
1609 (bfd *abfd, asection *section, bfd_byte **buf);
1610
1611 DESCRIPTION
1612 Read all data from @var{section} in BFD @var{abfd}
1613 into a buffer, *@var{buf}, malloc'd by this function.
1614 */
1615
1616 bool
1617 bfd_malloc_and_get_section (bfd *abfd, sec_ptr sec, bfd_byte **buf)
1618 {
1619 *buf = NULL;
1620 return bfd_get_full_section_contents (abfd, sec, buf);
1621 }
1622 /*
1623 FUNCTION
1624 bfd_copy_private_section_data
1625
1626 SYNOPSIS
1627 bool bfd_copy_private_section_data
1628 (bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
1629
1630 DESCRIPTION
1631 Copy private section information from @var{isec} in the BFD
1632 @var{ibfd} to the section @var{osec} in the BFD @var{obfd}.
1633 Return <<TRUE>> on success, <<FALSE>> on error. Possible error
1634 returns are:
1635
1636 o <<bfd_error_no_memory>> -
1637 Not enough memory exists to create private data for @var{osec}.
1638
1639 .#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
1640 . BFD_SEND (obfd, _bfd_copy_private_section_data, \
1641 . (ibfd, isection, obfd, osection))
1642 */
1643
1644 /*
1645 FUNCTION
1646 bfd_generic_is_group_section
1647
1648 SYNOPSIS
1649 bool bfd_generic_is_group_section (bfd *, const asection *sec);
1650
1651 DESCRIPTION
1652 Returns TRUE if @var{sec} is a member of a group.
1653 */
1654
1655 bool
1656 bfd_generic_is_group_section (bfd *abfd ATTRIBUTE_UNUSED,
1657 const asection *sec ATTRIBUTE_UNUSED)
1658 {
1659 return false;
1660 }
1661
1662 /*
1663 FUNCTION
1664 bfd_generic_group_name
1665
1666 SYNOPSIS
1667 const char *bfd_generic_group_name (bfd *, const asection *sec);
1668
1669 DESCRIPTION
1670 Returns group name if @var{sec} is a member of a group.
1671 */
1672
1673 const char *
1674 bfd_generic_group_name (bfd *abfd ATTRIBUTE_UNUSED,
1675 const asection *sec ATTRIBUTE_UNUSED)
1676 {
1677 return NULL;
1678 }
1679
1680 /*
1681 FUNCTION
1682 bfd_generic_discard_group
1683
1684 SYNOPSIS
1685 bool bfd_generic_discard_group (bfd *abfd, asection *group);
1686
1687 DESCRIPTION
1688 Remove all members of @var{group} from the output.
1689 */
1690
1691 bool
1692 bfd_generic_discard_group (bfd *abfd ATTRIBUTE_UNUSED,
1693 asection *group ATTRIBUTE_UNUSED)
1694 {
1695 return true;
1696 }
1697
1698 bool
1699 _bfd_nowrite_set_section_contents (bfd *abfd,
1700 sec_ptr section ATTRIBUTE_UNUSED,
1701 const void *location ATTRIBUTE_UNUSED,
1702 file_ptr offset ATTRIBUTE_UNUSED,
1703 bfd_size_type count ATTRIBUTE_UNUSED)
1704 {
1705 return _bfd_bool_bfd_false_error (abfd);
1706 }
1707
1708 /*
1709 INTERNAL_FUNCTION
1710 _bfd_section_size_insane
1711
1712 SYNOPSIS
1713 bool _bfd_section_size_insane (bfd *abfd, asection *sec);
1714
1715 DESCRIPTION
1716 Returns true if the given section has a size that indicates
1717 it cannot be read from file. Return false if the size is OK
1718 *or* this function can't say one way or the other.
1719
1720 */
1721
1722 bool
1723 _bfd_section_size_insane (bfd *abfd, asection *sec)
1724 {
1725 bfd_size_type size = bfd_get_section_limit_octets (abfd, sec);
1726 if (size == 0)
1727 return false;
1728
1729 if ((bfd_section_flags (sec) & SEC_IN_MEMORY) != 0
1730 /* PR 24753: Linker created sections can be larger than
1731 the file size, eg if they are being used to hold stubs. */
1732 || (bfd_section_flags (sec) & SEC_LINKER_CREATED) != 0
1733 /* PR 24753: Sections which have no content should also be
1734 excluded as they contain no size on disk. */
1735 || (bfd_section_flags (sec) & SEC_HAS_CONTENTS) == 0
1736 /* The MMO file format supports its own special compression
1737 technique, but it uses COMPRESS_SECTION_NONE when loading
1738 a section's contents. */
1739 || bfd_get_flavour (abfd) == bfd_target_mmo_flavour)
1740 return false;
1741
1742 ufile_ptr filesize = bfd_get_file_size (abfd);
1743 if (filesize == 0)
1744 return false;
1745
1746 if (sec->compress_status == DECOMPRESS_SECTION_ZSTD
1747 || sec->compress_status == DECOMPRESS_SECTION_ZLIB)
1748 {
1749 /* PR26946, PR28834: Sanity check compress header uncompressed
1750 size against the original file size, and check that the
1751 compressed section can be read from file. We choose an
1752 arbitrary uncompressed size of 10x the file size, rather than
1753 a compress ratio. The reason being that compiling
1754 "int aaa..a;" with "a" repeated enough times can result in
1755 compression ratios without limit for .debug_str, whereas such
1756 a file will usually also have the enormous symbol
1757 uncompressed in .symtab. */
1758 if (size / 10 > filesize)
1759 {
1760 bfd_set_error (bfd_error_bad_value);
1761 return true;
1762 }
1763 size = sec->compressed_size;
1764 }
1765
1766 if ((ufile_ptr) sec->filepos > filesize || size > filesize - sec->filepos)
1767 {
1768 bfd_set_error (bfd_error_file_truncated);
1769 return true;
1770 }
1771 return false;
1772 }