1 | /* simple-object-coff.c -- routines to manipulate COFF object files. |
---|---|
2 | Copyright (C) 2010-2025 Free Software Foundation, Inc. |
3 | Written by Ian Lance Taylor, Google. |
4 | |
5 | This program is free software; you can redistribute it and/or modify it |
6 | under the terms of the GNU General Public License as published by the |
7 | Free Software Foundation; either version 2, or (at your option) any |
8 | later version. |
9 | |
10 | This program is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | GNU General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU General Public License |
16 | along with this program; if not, write to the Free Software |
17 | Foundation, 51 Franklin Street - Fifth Floor, |
18 | Boston, MA 02110-1301, USA. */ |
19 | |
20 | #include "config.h" |
21 | #include "libiberty.h" |
22 | #include "simple-object.h" |
23 | |
24 | #include <errno.h> |
25 | #include <stddef.h> |
26 | |
27 | #ifdef HAVE_STDLIB_H |
28 | #include <stdlib.h> |
29 | #endif |
30 | |
31 | #ifdef HAVE_STDINT_H |
32 | #include <stdint.h> |
33 | #endif |
34 | |
35 | #ifdef HAVE_STRING_H |
36 | #include <string.h> |
37 | #endif |
38 | |
39 | #ifdef HAVE_INTTYPES_H |
40 | #include <inttypes.h> |
41 | #endif |
42 | |
43 | #include "simple-object-common.h" |
44 | |
45 | /* COFF structures and constants. */ |
46 | |
47 | /* COFF file header. */ |
48 | |
49 | struct external_filehdr |
50 | { |
51 | unsigned char f_magic[2]; /* magic number */ |
52 | unsigned char f_nscns[2]; /* number of sections */ |
53 | unsigned char f_timdat[4]; /* time & date stamp */ |
54 | unsigned char f_symptr[4]; /* file pointer to symtab */ |
55 | unsigned char f_nsyms[4]; /* number of symtab entries */ |
56 | unsigned char f_opthdr[2]; /* sizeof(optional hdr) */ |
57 | unsigned char f_flags[2]; /* flags */ |
58 | }; |
59 | |
60 | /* Bits for filehdr f_flags field. */ |
61 | |
62 | #define F_EXEC (0x0002) |
63 | #define IMAGE_FILE_SYSTEM (0x1000) |
64 | #define IMAGE_FILE_DLL (0x2000) |
65 | |
66 | /* COFF section header. */ |
67 | |
68 | struct external_scnhdr |
69 | { |
70 | unsigned char s_name[8]; /* section name */ |
71 | unsigned char s_paddr[4]; /* physical address, aliased s_nlib */ |
72 | unsigned char s_vaddr[4]; /* virtual address */ |
73 | unsigned char s_size[4]; /* section size */ |
74 | unsigned char s_scnptr[4]; /* file ptr to raw data for section */ |
75 | unsigned char s_relptr[4]; /* file ptr to relocation */ |
76 | unsigned char s_lnnoptr[4]; /* file ptr to line numbers */ |
77 | unsigned char s_nreloc[2]; /* number of relocation entries */ |
78 | unsigned char s_nlnno[2]; /* number of line number entries */ |
79 | unsigned char s_flags[4]; /* flags */ |
80 | }; |
81 | |
82 | /* The length of the s_name field in struct external_scnhdr. */ |
83 | |
84 | #define SCNNMLEN (8) |
85 | |
86 | /* Bits for scnhdr s_flags field. This includes some bits defined |
87 | only for PE. This may need to be moved into coff_magic. */ |
88 | |
89 | #define STYP_DATA (1 << 6) |
90 | #define IMAGE_SCN_MEM_DISCARDABLE (1 << 25) |
91 | #define IMAGE_SCN_MEM_SHARED (1 << 28) |
92 | #define IMAGE_SCN_MEM_READ (1 << 30) |
93 | |
94 | #define IMAGE_SCN_ALIGN_POWER_BIT_POS 20 |
95 | #define IMAGE_SCN_ALIGN_POWER_CONST(val) \ |
96 | (((val) + 1) << IMAGE_SCN_ALIGN_POWER_BIT_POS) |
97 | |
98 | /* COFF symbol table entry. */ |
99 | |
100 | #define E_SYMNMLEN 8 /* # characters in a symbol name */ |
101 | |
102 | struct external_syment |
103 | { |
104 | union |
105 | { |
106 | unsigned char e_name[E_SYMNMLEN]; |
107 | |
108 | struct |
109 | { |
110 | unsigned char e_zeroes[4]; |
111 | unsigned char e_offset[4]; |
112 | } e; |
113 | } e; |
114 | |
115 | unsigned char e_value[4]; |
116 | unsigned char e_scnum[2]; |
117 | unsigned char e_type[2]; |
118 | unsigned char e_sclass[1]; |
119 | unsigned char e_numaux[1]; |
120 | }; |
121 | |
122 | /* Length allowed for filename in aux sym format 4. */ |
123 | |
124 | #define E_FILNMLEN 18 |
125 | |
126 | /* Omits x_sym and other unused variants. */ |
127 | |
128 | union external_auxent |
129 | { |
130 | /* Aux sym format 4: file. */ |
131 | union |
132 | { |
133 | char x_fname[E_FILNMLEN]; |
134 | struct |
135 | { |
136 | unsigned char x_zeroes[4]; |
137 | unsigned char x_offset[4]; |
138 | } x_n; |
139 | } x_file; |
140 | /* Aux sym format 5: section. */ |
141 | struct |
142 | { |
143 | unsigned char x_scnlen[4]; /* section length */ |
144 | unsigned char x_nreloc[2]; /* # relocation entries */ |
145 | unsigned char x_nlinno[2]; /* # line numbers */ |
146 | unsigned char x_checksum[4]; /* section COMDAT checksum */ |
147 | unsigned char x_associated[2]; /* COMDAT assoc section index */ |
148 | unsigned char x_comdat[1]; /* COMDAT selection number */ |
149 | } x_scn; |
150 | }; |
151 | |
152 | /* Symbol-related constants. */ |
153 | |
154 | #define IMAGE_SYM_DEBUG (-2) |
155 | #define IMAGE_SYM_TYPE_NULL (0) |
156 | #define IMAGE_SYM_DTYPE_NULL (0) |
157 | #define IMAGE_SYM_CLASS_STATIC (3) |
158 | #define IMAGE_SYM_CLASS_FILE (103) |
159 | |
160 | #define IMAGE_SYM_TYPE \ |
161 | ((IMAGE_SYM_DTYPE_NULL << 4) | IMAGE_SYM_TYPE_NULL) |
162 | |
163 | /* Private data for an simple_object_read. */ |
164 | |
165 | struct simple_object_coff_read |
166 | { |
167 | /* Magic number. */ |
168 | unsigned short magic; |
169 | /* Whether the file is big-endian. */ |
170 | unsigned char is_big_endian; |
171 | /* Number of sections. */ |
172 | unsigned short nscns; |
173 | /* File offset of symbol table. */ |
174 | off_t symptr; |
175 | /* Number of symbol table entries. */ |
176 | unsigned int nsyms; |
177 | /* Flags. */ |
178 | unsigned short flags; |
179 | /* Offset of section headers in file. */ |
180 | off_t scnhdr_offset; |
181 | }; |
182 | |
183 | /* Private data for an simple_object_attributes. */ |
184 | |
185 | struct simple_object_coff_attributes |
186 | { |
187 | /* Magic number. */ |
188 | unsigned short magic; |
189 | /* Whether the file is big-endian. */ |
190 | unsigned char is_big_endian; |
191 | /* Flags. */ |
192 | unsigned short flags; |
193 | }; |
194 | |
195 | /* There is no magic number which indicates a COFF file as opposed to |
196 | any other sort of file. Instead, each COFF file starts with a |
197 | two-byte magic number which also indicates the type of the target. |
198 | This struct holds a magic number as well as characteristics of that |
199 | COFF format. */ |
200 | |
201 | struct coff_magic_struct |
202 | { |
203 | /* Magic number. */ |
204 | unsigned short magic; |
205 | /* Whether this magic number is for a big-endian file. */ |
206 | unsigned char is_big_endian; |
207 | /* Flag bits, in the f_flags fields, which indicates that this file |
208 | is not a relocatable object file. There is no flag which |
209 | specifically indicates a relocatable object file, it is only |
210 | implied by the absence of these flags. */ |
211 | unsigned short non_object_flags; |
212 | }; |
213 | |
214 | /* This is a list of the COFF magic numbers which we recognize, namely |
215 | the ones used on Windows. More can be added as needed. */ |
216 | |
217 | static const struct coff_magic_struct coff_magic[] = |
218 | { |
219 | /* i386. */ |
220 | { .magic: 0x14c, .is_big_endian: 0, F_EXEC | IMAGE_FILE_SYSTEM | IMAGE_FILE_DLL }, |
221 | /* x86_64. */ |
222 | { .magic: 0x8664, .is_big_endian: 0, F_EXEC | IMAGE_FILE_SYSTEM | IMAGE_FILE_DLL }, |
223 | /* AArch64. */ |
224 | { .magic: 0xaa64, .is_big_endian: 0, F_EXEC | IMAGE_FILE_SYSTEM | IMAGE_FILE_DLL } |
225 | }; |
226 | |
227 | /* See if we have a COFF file. */ |
228 | |
229 | static void * |
230 | simple_object_coff_match (unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN], |
231 | int descriptor, off_t offset, |
232 | const char *segment_name ATTRIBUTE_UNUSED, |
233 | const char **errmsg, int *err) |
234 | { |
235 | size_t c; |
236 | unsigned short magic_big; |
237 | unsigned short magic_little; |
238 | unsigned short magic; |
239 | size_t i; |
240 | int is_big_endian; |
241 | unsigned short (*fetch_16) (const unsigned char *); |
242 | unsigned int (*fetch_32) (const unsigned char *); |
243 | unsigned char hdrbuf[sizeof (struct external_filehdr)]; |
244 | unsigned short flags; |
245 | struct simple_object_coff_read *ocr; |
246 | |
247 | c = sizeof (coff_magic) / sizeof (coff_magic[0]); |
248 | magic_big = simple_object_fetch_big_16 (buf: header); |
249 | magic_little = simple_object_fetch_little_16 (buf: header); |
250 | for (i = 0; i < c; ++i) |
251 | { |
252 | if (coff_magic[i].is_big_endian |
253 | ? coff_magic[i].magic == magic_big |
254 | : coff_magic[i].magic == magic_little) |
255 | break; |
256 | } |
257 | if (i >= c) |
258 | { |
259 | *errmsg = NULL; |
260 | *err = 0; |
261 | return NULL; |
262 | } |
263 | is_big_endian = coff_magic[i].is_big_endian; |
264 | |
265 | magic = is_big_endian ? magic_big : magic_little; |
266 | fetch_16 = (is_big_endian |
267 | ? simple_object_fetch_big_16 |
268 | : simple_object_fetch_little_16); |
269 | fetch_32 = (is_big_endian |
270 | ? simple_object_fetch_big_32 |
271 | : simple_object_fetch_little_32); |
272 | |
273 | if (!simple_object_internal_read (descriptor, offset, buffer: hdrbuf, size: sizeof hdrbuf, |
274 | errmsg, err)) |
275 | return NULL; |
276 | |
277 | flags = fetch_16 (hdrbuf + offsetof (struct external_filehdr, f_flags)); |
278 | if ((flags & coff_magic[i].non_object_flags) != 0) |
279 | { |
280 | *errmsg = "not relocatable object file"; |
281 | *err = 0; |
282 | return NULL; |
283 | } |
284 | |
285 | ocr = XNEW (struct simple_object_coff_read); |
286 | ocr->magic = magic; |
287 | ocr->is_big_endian = is_big_endian; |
288 | ocr->nscns = fetch_16 (hdrbuf + offsetof (struct external_filehdr, f_nscns)); |
289 | ocr->symptr = fetch_32 (hdrbuf |
290 | + offsetof (struct external_filehdr, f_symptr)); |
291 | ocr->nsyms = fetch_32 (hdrbuf + offsetof (struct external_filehdr, f_nsyms)); |
292 | ocr->flags = flags; |
293 | ocr->scnhdr_offset = (sizeof (struct external_filehdr) |
294 | + fetch_16 (hdrbuf + offsetof (struct external_filehdr, |
295 | f_opthdr))); |
296 | |
297 | return (void *) ocr; |
298 | } |
299 | |
300 | /* Read the string table in a COFF file. */ |
301 | |
302 | static char * |
303 | simple_object_coff_read_strtab (simple_object_read *sobj, size_t *strtab_size, |
304 | const char **errmsg, int *err) |
305 | { |
306 | struct simple_object_coff_read *ocr = |
307 | (struct simple_object_coff_read *) sobj->data; |
308 | off_t strtab_offset; |
309 | unsigned char strsizebuf[4]; |
310 | size_t strsize; |
311 | char *strtab; |
312 | |
313 | strtab_offset = sobj->offset + ocr->symptr |
314 | + ocr->nsyms * sizeof (struct external_syment); |
315 | if (!simple_object_internal_read (descriptor: sobj->descriptor, offset: strtab_offset, |
316 | buffer: strsizebuf, size: 4, errmsg, err)) |
317 | return NULL; |
318 | strsize = (ocr->is_big_endian |
319 | ? simple_object_fetch_big_32 (buf: strsizebuf) |
320 | : simple_object_fetch_little_32 (buf: strsizebuf)); |
321 | strtab = XNEWVEC (char, strsize); |
322 | if (!simple_object_internal_read (descriptor: sobj->descriptor, offset: strtab_offset, |
323 | buffer: (unsigned char *) strtab, size: strsize, errmsg, |
324 | err)) |
325 | { |
326 | XDELETEVEC (strtab); |
327 | return NULL; |
328 | } |
329 | *strtab_size = strsize; |
330 | return strtab; |
331 | } |
332 | |
333 | /* Find all sections in a COFF file. */ |
334 | |
335 | static const char * |
336 | simple_object_coff_find_sections (simple_object_read *sobj, |
337 | int (*pfn) (void *, const char *, |
338 | off_t offset, off_t length), |
339 | void *data, |
340 | int *err) |
341 | { |
342 | struct simple_object_coff_read *ocr = |
343 | (struct simple_object_coff_read *) sobj->data; |
344 | size_t scnhdr_size; |
345 | unsigned char *scnbuf; |
346 | const char *errmsg; |
347 | unsigned int (*fetch_32) (const unsigned char *); |
348 | unsigned int nscns; |
349 | char *strtab; |
350 | size_t strtab_size; |
351 | unsigned int i; |
352 | |
353 | scnhdr_size = sizeof (struct external_scnhdr); |
354 | scnbuf = XNEWVEC (unsigned char, scnhdr_size * ocr->nscns); |
355 | if (!simple_object_internal_read (descriptor: sobj->descriptor, |
356 | offset: sobj->offset + ocr->scnhdr_offset, |
357 | buffer: scnbuf, size: scnhdr_size * ocr->nscns, errmsg: &errmsg, |
358 | err)) |
359 | { |
360 | XDELETEVEC (scnbuf); |
361 | return errmsg; |
362 | } |
363 | |
364 | fetch_32 = (ocr->is_big_endian |
365 | ? simple_object_fetch_big_32 |
366 | : simple_object_fetch_little_32); |
367 | |
368 | nscns = ocr->nscns; |
369 | strtab = NULL; |
370 | strtab_size = 0; |
371 | for (i = 0; i < nscns; ++i) |
372 | { |
373 | unsigned char *scnhdr; |
374 | unsigned char *scnname; |
375 | char namebuf[SCNNMLEN + 1]; |
376 | char *name; |
377 | off_t scnptr; |
378 | unsigned int size; |
379 | |
380 | scnhdr = scnbuf + i * scnhdr_size; |
381 | scnname = scnhdr + offsetof (struct external_scnhdr, s_name); |
382 | memcpy (dest: namebuf, src: scnname, SCNNMLEN); |
383 | namebuf[SCNNMLEN] = '\0'; |
384 | name = &namebuf[0]; |
385 | if (namebuf[0] == '/') |
386 | { |
387 | size_t strindex; |
388 | char *end; |
389 | |
390 | strindex = strtol (nptr: namebuf + 1, endptr: &end, base: 10); |
391 | if (*end == '\0') |
392 | { |
393 | /* The real section name is found in the string |
394 | table. */ |
395 | if (strtab == NULL) |
396 | { |
397 | strtab = simple_object_coff_read_strtab (sobj, |
398 | strtab_size: &strtab_size, |
399 | errmsg: &errmsg, err); |
400 | if (strtab == NULL) |
401 | { |
402 | XDELETEVEC (scnbuf); |
403 | return errmsg; |
404 | } |
405 | } |
406 | |
407 | if (strindex < 4 || strindex >= strtab_size) |
408 | { |
409 | XDELETEVEC (strtab); |
410 | XDELETEVEC (scnbuf); |
411 | *err = 0; |
412 | return "section string index out of range"; |
413 | } |
414 | |
415 | name = strtab + strindex; |
416 | } |
417 | } |
418 | |
419 | scnptr = fetch_32 (scnhdr + offsetof (struct external_scnhdr, s_scnptr)); |
420 | size = fetch_32 (scnhdr + offsetof (struct external_scnhdr, s_size)); |
421 | |
422 | if (!(*pfn) (data, name, scnptr, size)) |
423 | break; |
424 | } |
425 | |
426 | if (strtab != NULL) |
427 | XDELETEVEC (strtab); |
428 | XDELETEVEC (scnbuf); |
429 | |
430 | return NULL; |
431 | } |
432 | |
433 | /* Fetch the attributes for an simple_object_read. */ |
434 | |
435 | static void * |
436 | simple_object_coff_fetch_attributes (simple_object_read *sobj, |
437 | const char **errmsg ATTRIBUTE_UNUSED, |
438 | int *err ATTRIBUTE_UNUSED) |
439 | { |
440 | struct simple_object_coff_read *ocr = |
441 | (struct simple_object_coff_read *) sobj->data; |
442 | struct simple_object_coff_attributes *ret; |
443 | |
444 | ret = XNEW (struct simple_object_coff_attributes); |
445 | ret->magic = ocr->magic; |
446 | ret->is_big_endian = ocr->is_big_endian; |
447 | ret->flags = ocr->flags; |
448 | return ret; |
449 | } |
450 | |
451 | /* Release the private data for an simple_object_read. */ |
452 | |
453 | static void |
454 | simple_object_coff_release_read (void *data) |
455 | { |
456 | XDELETE (data); |
457 | } |
458 | |
459 | /* Compare two attributes structures. */ |
460 | |
461 | static const char * |
462 | simple_object_coff_attributes_merge (void *todata, void *fromdata, int *err) |
463 | { |
464 | struct simple_object_coff_attributes *to = |
465 | (struct simple_object_coff_attributes *) todata; |
466 | struct simple_object_coff_attributes *from = |
467 | (struct simple_object_coff_attributes *) fromdata; |
468 | |
469 | if (to->magic != from->magic || to->is_big_endian != from->is_big_endian) |
470 | { |
471 | *err = 0; |
472 | return "COFF object format mismatch"; |
473 | } |
474 | return NULL; |
475 | } |
476 | |
477 | /* Release the private data for an attributes structure. */ |
478 | |
479 | static void |
480 | simple_object_coff_release_attributes (void *data) |
481 | { |
482 | XDELETE (data); |
483 | } |
484 | |
485 | /* Prepare to write out a file. */ |
486 | |
487 | static void * |
488 | simple_object_coff_start_write (void *attributes_data, |
489 | const char **errmsg ATTRIBUTE_UNUSED, |
490 | int *err ATTRIBUTE_UNUSED) |
491 | { |
492 | struct simple_object_coff_attributes *attrs = |
493 | (struct simple_object_coff_attributes *) attributes_data; |
494 | struct simple_object_coff_attributes *ret; |
495 | |
496 | /* We're just going to record the attributes, but we need to make a |
497 | copy because the user may delete them. */ |
498 | ret = XNEW (struct simple_object_coff_attributes); |
499 | *ret = *attrs; |
500 | return ret; |
501 | } |
502 | |
503 | /* Write out a COFF filehdr. */ |
504 | |
505 | static int |
506 | simple_object_coff_write_filehdr (simple_object_write *sobj, int descriptor, |
507 | unsigned int nscns, size_t symtab_offset, |
508 | unsigned int nsyms, const char **errmsg, |
509 | int *err) |
510 | { |
511 | struct simple_object_coff_attributes *attrs = |
512 | (struct simple_object_coff_attributes *) sobj->data; |
513 | unsigned char hdrbuf[sizeof (struct external_filehdr)]; |
514 | unsigned char *hdr; |
515 | void (*set_16) (unsigned char *, unsigned short); |
516 | void (*set_32) (unsigned char *, unsigned int); |
517 | |
518 | hdr = &hdrbuf[0]; |
519 | |
520 | set_16 = (attrs->is_big_endian |
521 | ? simple_object_set_big_16 |
522 | : simple_object_set_little_16); |
523 | set_32 = (attrs->is_big_endian |
524 | ? simple_object_set_big_32 |
525 | : simple_object_set_little_32); |
526 | |
527 | memset (s: hdr, c: 0, n: sizeof (struct external_filehdr)); |
528 | |
529 | set_16 (hdr + offsetof (struct external_filehdr, f_magic), attrs->magic); |
530 | set_16 (hdr + offsetof (struct external_filehdr, f_nscns), nscns); |
531 | /* f_timdat left as zero. */ |
532 | set_32 (hdr + offsetof (struct external_filehdr, f_symptr), symtab_offset); |
533 | set_32 (hdr + offsetof (struct external_filehdr, f_nsyms), nsyms); |
534 | /* f_opthdr left as zero. */ |
535 | set_16 (hdr + offsetof (struct external_filehdr, f_flags), attrs->flags); |
536 | |
537 | return simple_object_internal_write (descriptor, offset: 0, buffer: hdrbuf, |
538 | size: sizeof (struct external_filehdr), |
539 | errmsg, err); |
540 | } |
541 | |
542 | /* Write out a COFF section header. */ |
543 | |
544 | static int |
545 | simple_object_coff_write_scnhdr (simple_object_write *sobj, int descriptor, |
546 | const char *name, size_t *name_offset, |
547 | off_t scnhdr_offset, size_t scnsize, |
548 | off_t offset, unsigned int align, |
549 | const char **errmsg, int *err) |
550 | { |
551 | struct simple_object_coff_attributes *attrs = |
552 | (struct simple_object_coff_attributes *) sobj->data; |
553 | void (*set_32) (unsigned char *, unsigned int); |
554 | unsigned char hdrbuf[sizeof (struct external_scnhdr)]; |
555 | unsigned char *hdr; |
556 | size_t namelen; |
557 | unsigned int flags; |
558 | |
559 | set_32 = (attrs->is_big_endian |
560 | ? simple_object_set_big_32 |
561 | : simple_object_set_little_32); |
562 | |
563 | memset (s: hdrbuf, c: 0, n: sizeof hdrbuf); |
564 | hdr = &hdrbuf[0]; |
565 | |
566 | namelen = strlen (s: name); |
567 | if (namelen <= SCNNMLEN) |
568 | strncpy (dest: (char *) hdr + offsetof (struct external_scnhdr, s_name), src: name, |
569 | SCNNMLEN); |
570 | else |
571 | { |
572 | snprintf (s: (char *) hdr + offsetof (struct external_scnhdr, s_name), |
573 | SCNNMLEN, format: "/%lu", (unsigned long) *name_offset); |
574 | *name_offset += namelen + 1; |
575 | } |
576 | |
577 | /* s_paddr left as zero. */ |
578 | /* s_vaddr left as zero. */ |
579 | set_32 (hdr + offsetof (struct external_scnhdr, s_size), scnsize); |
580 | set_32 (hdr + offsetof (struct external_scnhdr, s_scnptr), offset); |
581 | /* s_relptr left as zero. */ |
582 | /* s_lnnoptr left as zero. */ |
583 | /* s_nreloc left as zero. */ |
584 | /* s_nlnno left as zero. */ |
585 | flags = (STYP_DATA | IMAGE_SCN_MEM_DISCARDABLE | IMAGE_SCN_MEM_SHARED |
586 | | IMAGE_SCN_MEM_READ); |
587 | /* PE can represent alignment up to 13. */ |
588 | if (align > 13) |
589 | align = 13; |
590 | flags |= IMAGE_SCN_ALIGN_POWER_CONST(align); |
591 | set_32 (hdr + offsetof (struct external_scnhdr, s_flags), flags); |
592 | |
593 | return simple_object_internal_write (descriptor, offset: scnhdr_offset, buffer: hdrbuf, |
594 | size: sizeof (struct external_scnhdr), |
595 | errmsg, err); |
596 | } |
597 | |
598 | /* Write out a complete COFF file. */ |
599 | |
600 | static const char * |
601 | simple_object_coff_write_to_file (simple_object_write *sobj, int descriptor, |
602 | int *err) |
603 | { |
604 | struct simple_object_coff_attributes *attrs = |
605 | (struct simple_object_coff_attributes *) sobj->data; |
606 | unsigned int nscns, secnum; |
607 | simple_object_write_section *section; |
608 | off_t scnhdr_offset; |
609 | size_t symtab_offset; |
610 | off_t secsym_offset; |
611 | unsigned int nsyms; |
612 | size_t offset; |
613 | size_t name_offset; |
614 | const char *errmsg; |
615 | unsigned char strsizebuf[4]; |
616 | /* The interface doesn't give us access to the name of the input file |
617 | yet. We want to use its basename for the FILE symbol. This is |
618 | what 'gas' uses when told to assemble from stdin. */ |
619 | const char *source_filename = "fake"; |
620 | size_t sflen; |
621 | union |
622 | { |
623 | struct external_syment sym; |
624 | union external_auxent aux; |
625 | } syms[2]; |
626 | void (*set_16) (unsigned char *, unsigned short); |
627 | void (*set_32) (unsigned char *, unsigned int); |
628 | |
629 | set_16 = (attrs->is_big_endian |
630 | ? simple_object_set_big_16 |
631 | : simple_object_set_little_16); |
632 | set_32 = (attrs->is_big_endian |
633 | ? simple_object_set_big_32 |
634 | : simple_object_set_little_32); |
635 | |
636 | nscns = 0; |
637 | for (section = sobj->sections; section != NULL; section = section->next) |
638 | ++nscns; |
639 | |
640 | scnhdr_offset = sizeof (struct external_filehdr); |
641 | offset = scnhdr_offset + nscns * sizeof (struct external_scnhdr); |
642 | name_offset = 4; |
643 | for (section = sobj->sections; section != NULL; section = section->next) |
644 | { |
645 | size_t mask; |
646 | size_t new_offset; |
647 | size_t scnsize; |
648 | struct simple_object_write_section_buffer *buffer; |
649 | |
650 | mask = (1U << section->align) - 1; |
651 | new_offset = offset & mask; |
652 | new_offset &= ~ mask; |
653 | while (new_offset > offset) |
654 | { |
655 | unsigned char zeroes[16]; |
656 | size_t write; |
657 | |
658 | memset (s: zeroes, c: 0, n: sizeof zeroes); |
659 | write = new_offset - offset; |
660 | if (write > sizeof zeroes) |
661 | write = sizeof zeroes; |
662 | if (!simple_object_internal_write (descriptor, offset, buffer: zeroes, size: write, |
663 | errmsg: &errmsg, err)) |
664 | return errmsg; |
665 | } |
666 | |
667 | scnsize = 0; |
668 | for (buffer = section->buffers; buffer != NULL; buffer = buffer->next) |
669 | { |
670 | if (!simple_object_internal_write (descriptor, offset: offset + scnsize, |
671 | buffer: ((const unsigned char *) |
672 | buffer->buffer), |
673 | size: buffer->size, errmsg: &errmsg, err)) |
674 | return errmsg; |
675 | scnsize += buffer->size; |
676 | } |
677 | |
678 | if (!simple_object_coff_write_scnhdr (sobj, descriptor, name: section->name, |
679 | name_offset: &name_offset, scnhdr_offset, |
680 | scnsize, offset, align: section->align, |
681 | errmsg: &errmsg, err)) |
682 | return errmsg; |
683 | |
684 | scnhdr_offset += sizeof (struct external_scnhdr); |
685 | offset += scnsize; |
686 | } |
687 | |
688 | /* Symbol table is always half-word aligned. */ |
689 | offset += (offset & 1); |
690 | /* There is a file symbol and a section symbol per section, |
691 | and each of these has a single auxiliary symbol following. */ |
692 | nsyms = 2 * (nscns + 1); |
693 | symtab_offset = offset; |
694 | /* Advance across space reserved for symbol table to locate |
695 | start of string table. */ |
696 | offset += nsyms * sizeof (struct external_syment); |
697 | |
698 | /* Write out file symbol. */ |
699 | memset (s: &syms[0], c: 0, n: sizeof (syms)); |
700 | strcpy (dest: (char *)&syms[0].sym.e.e_name[0], src: ".file"); |
701 | set_16 (&syms[0].sym.e_scnum[0], IMAGE_SYM_DEBUG); |
702 | set_16 (&syms[0].sym.e_type[0], IMAGE_SYM_TYPE); |
703 | syms[0].sym.e_sclass[0] = IMAGE_SYM_CLASS_FILE; |
704 | syms[0].sym.e_numaux[0] = 1; |
705 | /* The name need not be nul-terminated if it fits into the x_fname field |
706 | directly, but must be if it has to be placed into the string table. */ |
707 | sflen = strlen (s: source_filename); |
708 | if (sflen <= E_FILNMLEN) |
709 | memcpy (dest: &syms[1].aux.x_file.x_fname[0], src: source_filename, n: sflen); |
710 | else |
711 | { |
712 | set_32 (&syms[1].aux.x_file.x_n.x_offset[0], name_offset); |
713 | if (!simple_object_internal_write (descriptor, offset: offset + name_offset, |
714 | buffer: ((const unsigned char *) |
715 | source_filename), |
716 | size: sflen + 1, errmsg: &errmsg, err)) |
717 | return errmsg; |
718 | name_offset += strlen (s: source_filename) + 1; |
719 | } |
720 | if (!simple_object_internal_write (descriptor, offset: symtab_offset, |
721 | buffer: (const unsigned char *) &syms[0], |
722 | size: sizeof (syms), errmsg: &errmsg, err)) |
723 | return errmsg; |
724 | |
725 | /* Write the string table length, followed by the strings and section |
726 | symbols in step with each other. */ |
727 | set_32 (strsizebuf, name_offset); |
728 | if (!simple_object_internal_write (descriptor, offset, buffer: strsizebuf, size: 4, |
729 | errmsg: &errmsg, err)) |
730 | return errmsg; |
731 | |
732 | name_offset = 4; |
733 | secsym_offset = symtab_offset + sizeof (syms); |
734 | memset (s: &syms[0], c: 0, n: sizeof (syms)); |
735 | set_16 (&syms[0].sym.e_type[0], IMAGE_SYM_TYPE); |
736 | syms[0].sym.e_sclass[0] = IMAGE_SYM_CLASS_STATIC; |
737 | syms[0].sym.e_numaux[0] = 1; |
738 | secnum = 1; |
739 | |
740 | for (section = sobj->sections; section != NULL; section = section->next) |
741 | { |
742 | size_t namelen; |
743 | size_t scnsize; |
744 | struct simple_object_write_section_buffer *buffer; |
745 | |
746 | namelen = strlen (s: section->name); |
747 | set_16 (&syms[0].sym.e_scnum[0], secnum++); |
748 | scnsize = 0; |
749 | for (buffer = section->buffers; buffer != NULL; buffer = buffer->next) |
750 | scnsize += buffer->size; |
751 | set_32 (&syms[1].aux.x_scn.x_scnlen[0], scnsize); |
752 | if (namelen > SCNNMLEN) |
753 | { |
754 | set_32 (&syms[0].sym.e.e.e_zeroes[0], 0); |
755 | set_32 (&syms[0].sym.e.e.e_offset[0], name_offset); |
756 | if (!simple_object_internal_write (descriptor, offset: offset + name_offset, |
757 | buffer: ((const unsigned char *) |
758 | section->name), |
759 | size: namelen + 1, errmsg: &errmsg, err)) |
760 | return errmsg; |
761 | name_offset += namelen + 1; |
762 | } |
763 | else |
764 | { |
765 | memcpy (dest: &syms[0].sym.e.e_name[0], src: section->name, |
766 | n: strlen (s: section->name)); |
767 | memset (s: &syms[0].sym.e.e_name[strlen (s: section->name)], c: 0, |
768 | E_SYMNMLEN - strlen (s: section->name)); |
769 | } |
770 | |
771 | if (!simple_object_internal_write (descriptor, offset: secsym_offset, |
772 | buffer: (const unsigned char *) &syms[0], |
773 | size: sizeof (syms), errmsg: &errmsg, err)) |
774 | return errmsg; |
775 | secsym_offset += sizeof (syms); |
776 | } |
777 | |
778 | if (!simple_object_coff_write_filehdr (sobj, descriptor, nscns, |
779 | symtab_offset, nsyms, errmsg: &errmsg, err)) |
780 | return errmsg; |
781 | |
782 | return NULL; |
783 | } |
784 | |
785 | /* Release the private data for an simple_object_write structure. */ |
786 | |
787 | static void |
788 | simple_object_coff_release_write (void *data) |
789 | { |
790 | XDELETE (data); |
791 | } |
792 | |
793 | /* The COFF functions. */ |
794 | |
795 | const struct simple_object_functions simple_object_coff_functions = |
796 | { |
797 | .match: simple_object_coff_match, |
798 | .find_sections: simple_object_coff_find_sections, |
799 | .fetch_attributes: simple_object_coff_fetch_attributes, |
800 | .release_read: simple_object_coff_release_read, |
801 | .attributes_merge: simple_object_coff_attributes_merge, |
802 | .release_attributes: simple_object_coff_release_attributes, |
803 | .start_write: simple_object_coff_start_write, |
804 | .write_to_file: simple_object_coff_write_to_file, |
805 | .release_write: simple_object_coff_release_write, |
806 | NULL |
807 | }; |
808 |
Definitions
- external_filehdr
- external_scnhdr
- external_syment
- external_auxent
- simple_object_coff_read
- simple_object_coff_attributes
- coff_magic_struct
- coff_magic
- simple_object_coff_match
- simple_object_coff_read_strtab
- simple_object_coff_find_sections
- simple_object_coff_fetch_attributes
- simple_object_coff_release_read
- simple_object_coff_attributes_merge
- simple_object_coff_release_attributes
- simple_object_coff_start_write
- simple_object_coff_write_filehdr
- simple_object_coff_write_scnhdr
- simple_object_coff_write_to_file
- simple_object_coff_release_write
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