1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * Copyright (c) 1988 AT&T
29 * All Rights Reserved
30 */
31
32 #include <memory.h>
33 #include <malloc.h>
34 #include <limits.h>
35
36 #include <sgs.h>
37 #include "decl.h"
38 #include "msg.h"
39
40 /*
41 * This module is compiled twice, the second time having
42 * -D_ELF64 defined. The following set of macros, along
43 * with machelf.h, represent the differences between the
44 * two compilations. Be careful *not* to add any class-
45 * dependent code (anything that has elf32 or elf64 in the
46 * name) to this code without hiding it behind a switch-
47 * able macro like these.
48 */
49 #if defined(_ELF64)
50
51 #define FSZ_LONG ELF64_FSZ_XWORD
52 #define ELFCLASS ELFCLASS64
53 #define _elf_snode_init _elf64_snode_init
54 #define _elfxx_cookscn _elf64_cookscn
55 #define _elf_upd_lib _elf64_upd_lib
56 #define elf_fsize elf64_fsize
57 #define _elf_entsz _elf64_entsz
58 #define _elf_msize _elf64_msize
59 #define _elf_upd_usr _elf64_upd_usr
60 #define wrt wrt64
61 #define elf_xlatetof elf64_xlatetof
62 #define _elfxx_update _elf64_update
63 #define _elfxx_swap_wrimage _elf64_swap_wrimage
64
65 #else /* ELF32 */
66
67 #define FSZ_LONG ELF32_FSZ_WORD
68 #define ELFCLASS ELFCLASS32
69 #define _elf_snode_init _elf32_snode_init
70 #define _elfxx_cookscn _elf32_cookscn
71 #define _elf_upd_lib _elf32_upd_lib
72 #define elf_fsize elf32_fsize
73 #define _elf_entsz _elf32_entsz
74 #define _elf_msize _elf32_msize
75 #define _elf_upd_usr _elf32_upd_usr
76 #define wrt wrt32
77 #define elf_xlatetof elf32_xlatetof
78 #define _elfxx_update _elf32_update
79 #define _elfxx_swap_wrimage _elf32_swap_wrimage
80
81 #endif /* ELF64 */
82
83
84 #if !(defined(_LP64) && defined(_ELF64))
85 #define TEST_SIZE
86
87 /*
88 * Handle the decision of whether the current linker can handle the
89 * desired object size, and if not, which error to issue.
90 *
91 * Input is the desired size. On failure, an error has been issued
92 * and 0 is returned. On success, 1 is returned.
93 */
94 static int
95 test_size(Lword hi)
96 {
97 #ifndef _LP64 /* 32-bit linker */
98 /*
99 * A 32-bit libelf is limited to a 2GB output file. This limit
100 * is due to the fact that off_t is a signed value, and that
101 * libelf cannot support large file support:
102 * - ABI reasons
103 * - Memory use generally is 2x output file size anyway,
104 * so lifting the file size limit will just send
105 * you crashing into the 32-bit VM limit.
106 * If the output is an ELFCLASS64 object, or an ELFCLASS32 object
107 * under 4GB, switching to the 64-bit version of libelf will help.
108 * However, an ELFCLASS32 object must not exceed 4GB.
109 */
110 if (hi > INT_MAX) { /* Bigger than 2GB */
111 #ifndef _ELF64
112 /* ELFCLASS32 object is fundamentally too big? */
113 if (hi > UINT_MAX) {
114 _elf_seterr(EFMT_FBIG_CLASS32, 0);
115 return (0);
116 }
117 #endif /* _ELF64 */
118
119 /* Should switch to the 64-bit libelf? */
120 _elf_seterr(EFMT_FBIG_LARGEFILE, 0);
121 return (0);
122 }
123 #endif /* !_LP64 */
124
125
126 #if defined(_LP64) && !defined(_ELF64) /* 64-bit linker, ELFCLASS32 */
127 /*
128 * A 64-bit linker can produce any size output
129 * file, but if the resulting file is ELFCLASS32,
130 * it must not exceed 4GB.
131 */
132 if (hi > UINT_MAX) {
133 _elf_seterr(EFMT_FBIG_CLASS32, 0);
134 return (0);
135 }
136 #endif
137
138 return (1);
139 }
140 #endif /* TEST_SIZE */
141
142 /*
143 * Output file update
144 * These functions walk an Elf structure, update its information,
145 * and optionally write the output file. Because the application
146 * may control of the output file layout, two upd_... routines
147 * exist. They're similar but too different to merge cleanly.
148 *
149 * The library defines a "dirty" bit to force parts of the file
150 * to be written on update. These routines ignore the dirty bit
151 * and do everything. A minimal update routine might be useful
152 * someday.
153 */
154
155 static size_t
156 _elf_upd_lib(Elf * elf)
157 {
158 NOTE(ASSUMING_PROTECTED(*elf))
159 Lword hi;
160 Lword hibit;
161 Elf_Scn * s;
162 register Lword sz;
163 Ehdr * eh = elf->ed_ehdr;
164 unsigned ver = eh->e_version;
165 register char *p = (char *)eh->e_ident;
166 size_t scncnt;
167
168 /*
169 * Ehdr and Phdr table go first
170 */
171 p[EI_MAG0] = ELFMAG0;
172 p[EI_MAG1] = ELFMAG1;
173 p[EI_MAG2] = ELFMAG2;
174 p[EI_MAG3] = ELFMAG3;
175 p[EI_CLASS] = ELFCLASS;
176 /* LINTED */
177 p[EI_VERSION] = (Byte)ver;
178 hi = elf_fsize(ELF_T_EHDR, 1, ver);
179 /* LINTED */
180 eh->e_ehsize = (Half)hi;
181 if (eh->e_phnum != 0) {
182 /* LINTED */
183 eh->e_phentsize = (Half)elf_fsize(ELF_T_PHDR, 1, ver);
184 /* LINTED */
185 eh->e_phoff = (Off)hi;
186 hi += eh->e_phentsize * eh->e_phnum;
187 } else {
188 eh->e_phoff = 0;
189 eh->e_phentsize = 0;
190 }
191
192 /*
193 * Obtain the first section header. Typically, this section has NULL
194 * contents, however in the case of Extended ELF Sections this section
195 * is used to hold an alternative e_shnum, e_shstrndx and e_phnum.
196 * On initial allocation (see _elf_snode) the elements of this section
197 * would have been zeroed. The e_shnum is initialized later, after the
198 * section header count has been determined. The e_shstrndx and
199 * e_phnum may have already been initialized by the caller (for example,
200 * gelf_update_shdr() in mcs(1)).
201 */
202 if ((s = elf->ed_hdscn) == 0) {
203 eh->e_shnum = 0;
204 scncnt = 0;
205 } else {
206 s = s->s_next;
207 scncnt = 1;
208 }
209
210 /*
211 * Loop through sections. Compute section size before changing hi.
212 * Allow null buffers for NOBITS.
213 */
214 hibit = 0;
215 for (; s != 0; s = s->s_next) {
216 register Dnode *d;
217 register Lword fsz, j;
218 Shdr *sh = s->s_shdr;
219
220 scncnt++;
221 if (sh->sh_type == SHT_NULL) {
222 *sh = _elf_snode_init.sb_shdr;
223 continue;
224 }
225
226 if ((s->s_myflags & SF_READY) == 0)
227 (void) _elfxx_cookscn(s);
228
229 sh->sh_addralign = 1;
230 if ((sz = (Lword)_elf_entsz(elf, sh->sh_type, ver)) != 0)
231 /* LINTED */
232 sh->sh_entsize = (Half)sz;
233 sz = 0;
234 for (d = s->s_hdnode; d != 0; d = d->db_next) {
235 if ((fsz = elf_fsize(d->db_data.d_type,
236 1, ver)) == 0)
237 return (0);
238
239 j = _elf_msize(d->db_data.d_type, ver);
240 fsz *= (d->db_data.d_size / j);
241 d->db_osz = (size_t)fsz;
242 if ((j = d->db_data.d_align) > 1) {
243 if (j > sh->sh_addralign)
244 sh->sh_addralign = (Xword)j;
245
246 if (sz % j != 0)
247 sz += j - sz % j;
248 }
249 d->db_data.d_off = (off_t)sz;
250 d->db_xoff = sz;
251 sz += fsz;
252 }
253
254 sh->sh_size = (Xword) sz;
255 /*
256 * We want to take into account the offsets for NOBITS
257 * sections and let the "sh_offsets" point to where
258 * the section would 'conceptually' fit within
259 * the file (as required by the ABI).
260 *
261 * But - we must also make sure that the NOBITS does
262 * not take up any actual space in the file. We preserve
263 * the actual offset into the file in the 'hibit' variable.
264 * When we come to the first non-NOBITS section after a
265 * encountering a NOBITS section the hi counter is restored
266 * to its proper place in the file.
267 */
268 if (sh->sh_type == SHT_NOBITS) {
269 if (hibit == 0)
270 hibit = hi;
271 } else {
272 if (hibit) {
273 hi = hibit;
274 hibit = 0;
275 }
276 }
277 j = sh->sh_addralign;
278 if ((fsz = hi % j) != 0)
279 hi += j - fsz;
280
281 /* LINTED */
282 sh->sh_offset = (Off)hi;
283 hi += sz;
284 }
285
286 /*
287 * if last section was a 'NOBITS' section then we need to
288 * restore the 'hi' counter to point to the end of the last
289 * non 'NOBITS' section.
290 */
291 if (hibit) {
292 hi = hibit;
293 hibit = 0;
294 }
295
296 /*
297 * Shdr table last
298 */
299 if (scncnt != 0) {
300 if (hi % FSZ_LONG != 0)
301 hi += FSZ_LONG - hi % FSZ_LONG;
302 /* LINTED */
303 eh->e_shoff = (Off)hi;
304 /*
305 * If we are using 'extended sections' then the
306 * e_shnum is stored in the sh_size field of the
307 * first section header.
308 *
309 * NOTE: we set e_shnum to '0' because it's specified
310 * this way in the gABI, and in the hopes that
311 * this will cause less problems to unaware
312 * tools then if we'd set it to SHN_XINDEX (0xffff).
313 */
314 if (scncnt < SHN_LORESERVE)
315 eh->e_shnum = scncnt;
316 else {
317 Shdr *sh;
318 sh = (Shdr *)elf->ed_hdscn->s_shdr;
319 sh->sh_size = scncnt;
320 eh->e_shnum = 0;
321 }
322 /* LINTED */
323 eh->e_shentsize = (Half)elf_fsize(ELF_T_SHDR, 1, ver);
324 hi += eh->e_shentsize * scncnt;
325 } else {
326 eh->e_shoff = 0;
327 eh->e_shentsize = 0;
328 }
329
330 #ifdef TEST_SIZE
331 if (test_size(hi) == 0)
332 return (0);
333 #endif
334
335 return ((size_t)hi);
336 }
337
338
339
340 static size_t
341 _elf_upd_usr(Elf * elf)
342 {
343 NOTE(ASSUMING_PROTECTED(*elf))
344 Lword hi;
345 Elf_Scn * s;
346 register Lword sz;
347 Ehdr * eh = elf->ed_ehdr;
348 unsigned ver = eh->e_version;
349 register char *p = (char *)eh->e_ident;
350
351
352 /*
353 * Ehdr and Phdr table go first
354 */
355 p[EI_MAG0] = ELFMAG0;
356 p[EI_MAG1] = ELFMAG1;
357 p[EI_MAG2] = ELFMAG2;
358 p[EI_MAG3] = ELFMAG3;
359 p[EI_CLASS] = ELFCLASS;
360 /* LINTED */
361 p[EI_VERSION] = (Byte)ver;
362 hi = elf_fsize(ELF_T_EHDR, 1, ver);
363 /* LINTED */
364 eh->e_ehsize = (Half)hi;
365
366 /*
367 * If phnum is zero, phoff "should" be zero too,
368 * but the application is responsible for it.
369 * Allow a non-zero value here and update the
370 * hi water mark accordingly.
371 */
372
373 if (eh->e_phnum != 0)
374 /* LINTED */
375 eh->e_phentsize = (Half)elf_fsize(ELF_T_PHDR, 1, ver);
376 else
377 eh->e_phentsize = 0;
378 if ((sz = eh->e_phoff + eh->e_phentsize * eh->e_phnum) > hi)
379 hi = sz;
380
381 /*
382 * Loop through sections, skipping index zero.
383 * Compute section size before changing hi.
384 * Allow null buffers for NOBITS.
385 */
386
387 if ((s = elf->ed_hdscn) == 0)
388 eh->e_shnum = 0;
389 else {
390 eh->e_shnum = 1;
391 *(Shdr*)s->s_shdr = _elf_snode_init.sb_shdr;
392 s = s->s_next;
393 }
394 for (; s != 0; s = s->s_next) {
395 register Dnode *d;
396 register Lword fsz, j;
397 Shdr *sh = s->s_shdr;
398
399 if ((s->s_myflags & SF_READY) == 0)
400 (void) _elfxx_cookscn(s);
401
402 ++eh->e_shnum;
403 sz = 0;
404 for (d = s->s_hdnode; d != 0; d = d->db_next) {
405 if ((fsz = elf_fsize(d->db_data.d_type, 1,
406 ver)) == 0)
407 return (0);
408 j = _elf_msize(d->db_data.d_type, ver);
409 fsz *= (d->db_data.d_size / j);
410 d->db_osz = (size_t)fsz;
411
412 if ((sh->sh_type != SHT_NOBITS) &&
413 ((j = (d->db_data.d_off + d->db_osz)) > sz))
414 sz = j;
415 }
416 if (sh->sh_size < sz) {
417 _elf_seterr(EFMT_SCNSZ, 0);
418 return (0);
419 }
420 if ((sh->sh_type != SHT_NOBITS) &&
421 (hi < sh->sh_offset + sh->sh_size))
422 hi = sh->sh_offset + sh->sh_size;
423 }
424
425 /*
426 * Shdr table last. Comment above for phnum/phoff applies here.
427 */
428 if (eh->e_shnum != 0)
429 /* LINTED */
430 eh->e_shentsize = (Half)elf_fsize(ELF_T_SHDR, 1, ver);
431 else
432 eh->e_shentsize = 0;
433
434 if ((sz = eh->e_shoff + eh->e_shentsize * eh->e_shnum) > hi)
435 hi = sz;
436
437 #ifdef TEST_SIZE
438 if (test_size(hi) == 0)
439 return (0);
440 #endif
441
442 return ((size_t)hi);
443 }
444
445
446 static size_t
447 wrt(Elf * elf, Xword outsz, unsigned fill, int update_cmd)
448 {
449 NOTE(ASSUMING_PROTECTED(*elf))
450 Elf_Data dst, src;
451 unsigned flag;
452 Xword hi, sz;
453 char *image;
454 Elf_Scn *s;
455 Ehdr *eh = elf->ed_ehdr;
456 unsigned ver = eh->e_version;
457 unsigned encode;
458 int byte;
459 _elf_execfill_func_t *execfill_func;
460
461 /*
462 * If this is an ELF_C_WRIMAGE write, then we encode into the
463 * byte order of the system we are running on rather than that of
464 * of the object. For ld.so.1, this is the same order, but
465 * for 'ld', it might not be in the case where we are cross
466 * linking an object for a different target. In this later case,
467 * the linker-host byte order is necessary so that the linker can
468 * manipulate the resulting image. It is expected that the linker
469 * will call elf_swap_wrimage() if necessary to convert the image
470 * to the target byte order.
471 */
472 encode = (update_cmd == ELF_C_WRIMAGE) ? _elf_sys_encoding() :
473 eh->e_ident[EI_DATA];
474
475 /*
476 * Two issues can cause trouble for the output file.
477 * First, begin() with ELF_C_RDWR opens a file for both
478 * read and write. On the write update(), the library
479 * has to read everything it needs before truncating
480 * the file. Second, using mmap for both read and write
481 * is too tricky. Consequently, the library disables mmap
482 * on the read side. Using mmap for the output saves swap
483 * space, because that mapping is SHARED, not PRIVATE.
484 *
485 * If the file is write-only, there can be nothing of
486 * interest to bother with.
487 *
488 * The following reads the entire file, which might be
489 * more than necessary. Better safe than sorry.
490 */
491
492 if ((elf->ed_myflags & EDF_READ) &&
493 (_elf_vm(elf, (size_t)0, elf->ed_fsz) != OK_YES))
494 return (0);
495
496 flag = elf->ed_myflags & EDF_WRALLOC;
497 if ((image = _elf_outmap(elf->ed_fd, outsz, &flag)) == 0)
498 return (0);
499
500 if (flag == 0)
501 elf->ed_myflags |= EDF_IMALLOC;
502
503 /*
504 * If an error occurs below, a "dirty" bit may be cleared
505 * improperly. To save a second pass through the file,
506 * this code sets the dirty bit on the elf descriptor
507 * when an error happens, assuming that will "cover" any
508 * accidents.
509 */
510
511 /*
512 * Hi is needed only when 'fill' is non-zero.
513 * Fill is non-zero only when the library
514 * calculates file/section/data buffer offsets.
515 * The lib guarantees they increase monotonically.
516 * That guarantees proper filling below.
517 */
518
519
520 /*
521 * Ehdr first
522 */
523
524 src.d_buf = (Elf_Void *)eh;
525 src.d_type = ELF_T_EHDR;
526 src.d_size = sizeof (Ehdr);
527 src.d_version = EV_CURRENT;
528 dst.d_buf = (Elf_Void *)image;
529 dst.d_size = eh->e_ehsize;
530 dst.d_version = ver;
531 if (elf_xlatetof(&dst, &src, encode) == 0)
532 return (0);
533 elf->ed_ehflags &= ~ELF_F_DIRTY;
534 hi = eh->e_ehsize;
535
536 /*
537 * Phdr table if one exists
538 */
539
540 if (eh->e_phnum != 0) {
541 unsigned work;
542 /*
543 * Unlike other library data, phdr table is
544 * in the user version. Change src buffer
545 * version here, fix it after translation.
546 */
547
548 src.d_buf = (Elf_Void *)elf->ed_phdr;
549 src.d_type = ELF_T_PHDR;
550 src.d_size = elf->ed_phdrsz;
551 ELFACCESSDATA(work, _elf_work)
552 src.d_version = work;
553 dst.d_buf = (Elf_Void *)(image + eh->e_phoff);
554 dst.d_size = eh->e_phnum * eh->e_phentsize;
555 hi = (Xword)(eh->e_phoff + dst.d_size);
556 if (elf_xlatetof(&dst, &src, encode) == 0) {
557 elf->ed_uflags |= ELF_F_DIRTY;
558 return (0);
559 }
560 elf->ed_phflags &= ~ELF_F_DIRTY;
561 src.d_version = EV_CURRENT;
562 }
563
564 /*
565 * Loop through sections
566 */
567
568 ELFACCESSDATA(byte, _elf_byte);
569 ELFACCESSDATA(execfill_func, _elf_execfill_func);
570 for (s = elf->ed_hdscn; s != 0; s = s->s_next) {
571 register Dnode *d, *prevd;
572 Xword off = 0;
573 Shdr *sh = s->s_shdr;
574 char *start = image + sh->sh_offset;
575 char *here;
576 _elf_execfill_func_t *execfill;
577
578 /* Only use the execfill function on SHF_EXECINSTR sections */
579 execfill = (sh->sh_flags & SHF_EXECINSTR) ?
580 execfill_func : NULL;
581
582 /*
583 * Just "clean" DIRTY flag for "empty" sections. Even if
584 * NOBITS needs padding, the next thing in the
585 * file will provide it. (And if this NOBITS is
586 * the last thing in the file, no padding needed.)
587 */
588 if ((sh->sh_type == SHT_NOBITS) ||
589 (sh->sh_type == SHT_NULL)) {
590 d = s->s_hdnode, prevd = 0;
591 for (; d != 0; prevd = d, d = d->db_next)
592 d->db_uflags &= ~ELF_F_DIRTY;
593 continue;
594 }
595 /*
596 * Clear out the memory between the end of the last
597 * section and the begining of this section.
598 */
599 if (fill && (sh->sh_offset > hi)) {
600 sz = sh->sh_offset - hi;
601 (void) memset(start - sz, byte, sz);
602 }
603
604
605 for (d = s->s_hdnode, prevd = 0;
606 d != 0; prevd = d, d = d->db_next) {
607 d->db_uflags &= ~ELF_F_DIRTY;
608 here = start + d->db_data.d_off;
609
610 /*
611 * Clear out the memory between the end of the
612 * last update and the start of this data buffer.
613 *
614 * These buffers represent input sections that have
615 * been concatenated into an output section, so if
616 * the output section is executable (SHF_EXECINSTR)
617 * and a fill function has been registered, use the
618 * function. Otherwise, use the fill byte.
619 */
620 if (fill && (d->db_data.d_off > off)) {
621 sz = (Xword)(d->db_data.d_off - off);
622 if (execfill != NULL)
623 (* execfill)(start,
624 here - start - sz, sz);
625 else
626 (void) memset(here - sz, byte, sz);
627 }
628
629 if ((d->db_myflags & DBF_READY) == 0) {
630 SCNLOCK(s);
631 if (_elf_locked_getdata(s, &prevd->db_data) !=
632 &d->db_data) {
633 elf->ed_uflags |= ELF_F_DIRTY;
634 SCNUNLOCK(s);
635 return (0);
636 }
637 SCNUNLOCK(s);
638 }
639 dst.d_buf = (Elf_Void *)here;
640 dst.d_size = d->db_osz;
641
642 /*
643 * Copy the translated bits out to the destination
644 * image.
645 */
646 if (elf_xlatetof(&dst, &d->db_data, encode) == 0) {
647 elf->ed_uflags |= ELF_F_DIRTY;
648 return (0);
649 }
650
651 off = (Xword)(d->db_data.d_off + dst.d_size);
652 }
653 hi = sh->sh_offset + sh->sh_size;
654 }
655
656 /*
657 * Shdr table last
658 */
659
660 if (fill && (eh->e_shoff > hi)) {
661 sz = eh->e_shoff - hi;
662 (void) memset(image + hi, byte, sz);
663 }
664
665 src.d_type = ELF_T_SHDR;
666 src.d_size = sizeof (Shdr);
667 dst.d_buf = (Elf_Void *)(image + eh->e_shoff);
668 dst.d_size = eh->e_shentsize;
669 for (s = elf->ed_hdscn; s != 0; s = s->s_next) {
670 assert((uintptr_t)dst.d_buf < ((uintptr_t)image + outsz));
671 s->s_shflags &= ~ELF_F_DIRTY;
672 s->s_uflags &= ~ELF_F_DIRTY;
673 src.d_buf = s->s_shdr;
674
675 if (elf_xlatetof(&dst, &src, encode) == 0) {
676 elf->ed_uflags |= ELF_F_DIRTY;
677 return (0);
678 }
679
680 dst.d_buf = (char *)dst.d_buf + eh->e_shentsize;
681 }
682 /*
683 * ELF_C_WRIMAGE signifyes that we build the memory image, but
684 * that we do not actually write it to disk. This is used
685 * by ld(1) to build up a full image of an elf file and then
686 * to process the file before it's actually written out to
687 * disk. This saves ld(1) the overhead of having to write
688 * the image out to disk twice.
689 */
690 if (update_cmd == ELF_C_WRIMAGE) {
691 elf->ed_uflags &= ~ELF_F_DIRTY;
692 elf->ed_wrimage = image;
693 elf->ed_wrimagesz = outsz;
694 return (outsz);
695 }
696
697 if (_elf_outsync(elf->ed_fd, image, outsz,
698 ((elf->ed_myflags & EDF_IMALLOC) ? 0 : 1)) != 0) {
699 elf->ed_uflags &= ~ELF_F_DIRTY;
700 elf->ed_myflags &= ~EDF_IMALLOC;
701 return (outsz);
702 }
703
704 elf->ed_uflags |= ELF_F_DIRTY;
705 return (0);
706 }
707
708
709
710
711 /*
712 * The following is a private interface between the linkers (ld & ld.so.1)
713 * and libelf:
714 *
715 * elf_update(elf, ELF_C_WRIMAGE)
716 * This will cause full image representing the elf file
717 * described by the elf pointer to be built in memory. If the
718 * elf pointer has a valid file descriptor associated with it
719 * we will attempt to build the memory image from mmap()'ed
720 * storage. If the elf descriptor does not have a valid
721 * file descriptor (opened with elf_begin(0, ELF_C_IMAGE, 0))
722 * then the image will be allocated from dynamic memory (malloc()).
723 *
724 * elf_update() will return the size of the memory image built
725 * when sucessful.
726 *
727 * When a subsequent call to elf_update() with ELF_C_WRITE as
728 * the command is performed it will sync the image created
729 * by ELF_C_WRIMAGE to disk (if fd available) and
730 * free the memory allocated.
731 */
732
733 off_t
734 _elfxx_update(Elf * elf, Elf_Cmd cmd)
735 {
736 size_t sz;
737 unsigned u;
738 Ehdr *eh = elf->ed_ehdr;
739
740 if (elf == 0)
741 return (-1);
742
743 ELFWLOCK(elf)
744 switch (cmd) {
745 default:
746 _elf_seterr(EREQ_UPDATE, 0);
747 ELFUNLOCK(elf)
748 return (-1);
749
750 case ELF_C_WRIMAGE:
751 if ((elf->ed_myflags & EDF_WRITE) == 0) {
752 _elf_seterr(EREQ_UPDWRT, 0);
753 ELFUNLOCK(elf)
754 return (-1);
755 }
756 break;
757 case ELF_C_WRITE:
758 if ((elf->ed_myflags & EDF_WRITE) == 0) {
759 _elf_seterr(EREQ_UPDWRT, 0);
760 ELFUNLOCK(elf)
761 return (-1);
762 }
763 if (elf->ed_wrimage) {
764 if (elf->ed_myflags & EDF_WRALLOC) {
765 free(elf->ed_wrimage);
766 /*
767 * The size is still returned even
768 * though nothing is actually written
769 * out. This is just to be consistant
770 * with the rest of the interface.
771 */
772 sz = elf->ed_wrimagesz;
773 elf->ed_wrimage = 0;
774 elf->ed_wrimagesz = 0;
775 ELFUNLOCK(elf);
776 return ((off_t)sz);
777 }
778 sz = _elf_outsync(elf->ed_fd, elf->ed_wrimage,
779 elf->ed_wrimagesz,
780 (elf->ed_myflags & EDF_IMALLOC ? 0 : 1));
781 elf->ed_myflags &= ~EDF_IMALLOC;
782 elf->ed_wrimage = 0;
783 elf->ed_wrimagesz = 0;
784 ELFUNLOCK(elf);
785 return ((off_t)sz);
786 }
787 /* FALLTHROUGH */
788 case ELF_C_NULL:
789 break;
790 }
791
792 if (eh == 0) {
793 _elf_seterr(ESEQ_EHDR, 0);
794 ELFUNLOCK(elf)
795 return (-1);
796 }
797
798 if ((u = eh->e_version) > EV_CURRENT) {
799 _elf_seterr(EREQ_VER, 0);
800 ELFUNLOCK(elf)
801 return (-1);
802 }
803
804 if (u == EV_NONE)
805 eh->e_version = EV_CURRENT;
806
807 if ((u = eh->e_ident[EI_DATA]) == ELFDATANONE) {
808 unsigned encode;
809
810 ELFACCESSDATA(encode, _elf_encode)
811 if (encode == ELFDATANONE) {
812 _elf_seterr(EREQ_ENCODE, 0);
813 ELFUNLOCK(elf)
814 return (-1);
815 }
816 /* LINTED */
817 eh->e_ident[EI_DATA] = (Byte)encode;
818 }
819
820 u = 1;
821 if (elf->ed_uflags & ELF_F_LAYOUT) {
822 sz = _elf_upd_usr(elf);
823 u = 0;
824 } else
825 sz = _elf_upd_lib(elf);
826
827 if ((sz != 0) && ((cmd == ELF_C_WRITE) || (cmd == ELF_C_WRIMAGE)))
828 sz = wrt(elf, (Xword)sz, u, cmd);
829
830 if (sz == 0) {
831 ELFUNLOCK(elf)
832 return (-1);
833 }
834
835 ELFUNLOCK(elf)
836 return ((off_t)sz);
837 }
838
839
840 /*
841 * When wrt() processes an ELF_C_WRIMAGE request, the resulting image
842 * gets the byte order (encoding) of the platform running the linker
843 * rather than that of the target host. This allows the linker to modify
844 * the image, prior to flushing it to the output file. This routine
845 * is used to re-translate such an image into the byte order of the
846 * target host.
847 */
848 int
849 _elfxx_swap_wrimage(Elf *elf)
850 {
851 Elf_Data dst, src;
852 Elf_Scn *s;
853 Ehdr *eh;
854 Half e_phnum;
855 unsigned ver;
856 unsigned encode;
857
858 /*
859 * Ehdr first
860 */
861
862 ELFWLOCK(elf);
863 eh = elf->ed_ehdr;
864 e_phnum = eh->e_phnum;
865 ver = eh->e_version;
866 encode = eh->e_ident[EI_DATA];
867
868 src.d_buf = dst.d_buf = (Elf_Void *)eh;
869 src.d_type = dst.d_type = ELF_T_EHDR;
870 src.d_size = dst.d_size = sizeof (Ehdr);
871 src.d_version = dst.d_version = ver;
872 if (elf_xlatetof(&dst, &src, encode) == 0) {
873 ELFUNLOCK(elf);
874 return (1);
875 }
876
877 /*
878 * Phdr table if one exists
879 */
880
881 if (e_phnum != 0) {
882 unsigned work;
883 /*
884 * Unlike other library data, phdr table is
885 * in the user version.
886 */
887
888 src.d_buf = dst.d_buf = (Elf_Void *)elf->ed_phdr;
889 src.d_type = dst.d_type = ELF_T_PHDR;
890 src.d_size = dst.d_size = elf->ed_phdrsz;
891 ELFACCESSDATA(work, _elf_work)
892 src.d_version = dst.d_version = work;
893 if (elf_xlatetof(&dst, &src, encode) == 0) {
894 ELFUNLOCK(elf);
895 return (1);
896 }
897 }
898
899 /*
900 * Loop through sections
901 */
902
903 for (s = elf->ed_hdscn; s != 0; s = s->s_next) {
904 register Dnode *d, *prevd;
905 Shdr *sh = s->s_shdr;
906
907 if ((sh->sh_type == SHT_NOBITS) || (sh->sh_type == SHT_NULL))
908 continue;
909
910 for (d = s->s_hdnode, prevd = 0;
911 d != 0; prevd = d, d = d->db_next) {
912
913 if ((d->db_myflags & DBF_READY) == 0) {
914 SCNLOCK(s);
915 if (_elf_locked_getdata(s, &prevd->db_data) !=
916 &d->db_data) {
917 SCNUNLOCK(s);
918 ELFUNLOCK(elf);
919 return (1);
920 }
921 SCNUNLOCK(s);
922 }
923
924 dst = d->db_data;
925 if (elf_xlatetof(&dst, &d->db_data, encode) == 0) {
926 ELFUNLOCK(elf);
927 return (1);
928 }
929 }
930 }
931
932 /*
933 * Shdr table
934 */
935
936 src.d_type = dst.d_type = ELF_T_SHDR;
937 src.d_version = dst.d_version = ver;
938 for (s = elf->ed_hdscn; s != 0; s = s->s_next) {
939 src.d_buf = dst.d_buf = s->s_shdr;
940 src.d_size = dst.d_size = sizeof (Shdr);
941 if (elf_xlatetof(&dst, &src, encode) == 0) {
942 ELFUNLOCK(elf);
943 return (1);
944 }
945 }
946
947 ELFUNLOCK(elf);
948 return (0);
949 }
950
951
952
953 #ifndef _ELF64
954 /* class-independent, only needs to be compiled once */
955
956 off_t
957 elf_update(Elf *elf, Elf_Cmd cmd)
958 {
959 if (elf == 0)
960 return (-1);
961
962 if (elf->ed_class == ELFCLASS32)
963 return (_elf32_update(elf, cmd));
964 else if (elf->ed_class == ELFCLASS64) {
965 return (_elf64_update(elf, cmd));
966 }
967
968 _elf_seterr(EREQ_CLASS, 0);
969 return (-1);
970 }
971
972 int
973 _elf_swap_wrimage(Elf *elf)
974 {
975 if (elf == 0)
976 return (0);
977
978 if (elf->ed_class == ELFCLASS32)
979 return (_elf32_swap_wrimage(elf));
980
981 if (elf->ed_class == ELFCLASS64)
982 return (_elf64_swap_wrimage(elf));
983
984 _elf_seterr(EREQ_CLASS, 0);
985 return (0);
986 }
987
988 /*
989 * 4106312, 4106398, This is an ad-hoc means for the 32-bit
990 * Elf64 version of libld.so.3 to get around the limitation
991 * of a 32-bit d_off field. This is only intended to be
992 * used by libld to relocate symbols in large NOBITS sections.
993 */
994 Elf64_Off
995 _elf_getxoff(Elf_Data * d)
996 {
997 return (((Dnode *)d)->db_xoff);
998 }
999 #endif /* !_ELF64 */