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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26 #include <string.h>
27 #include <stdio.h>
28 #include <sys/types.h>
29 #include <sgs.h>
30 #include <debug.h>
31 #include <_libld.h>
32 #include <dwarf.h>
33 #include <stdlib.h>
34
35 /*
36 * A EH_FRAME_HDR consists of the following:
37 *
38 * Encoding Field
39 * --------------------------------
40 * unsigned byte version
41 * unsigned byte eh_frame_ptr_enc
42 * unsigned byte fde_count_enc
43 * unsigned byte table_enc
44 * encoded eh_frame_ptr
45 * encoded fde_count
46 * [ binary search table ]
47 *
48 * The binary search table entries each consists of:
49 *
50 * encoded initial_func_loc
51 * encoded FDE_address
52 *
53 * The entries in the binary search table are sorted
54 * in a increasing order by the initial location.
55 *
56 *
57 * version
58 *
59 * Version of the .eh_frame_hdr format. This value shall be 1.
60 *
61 * eh_frame_ptr_enc
62 *
63 * The encoding format of the eh_frame_ptr field. For shared
64 * libraries the encoding must be
65 * DW_EH_PE_sdata4|DW_EH_PE_pcrel or
66 * DW_EH_PE_sdata4|DW_EH_PE_datarel.
67 *
68 *
69 * fde_count_enc
70 *
71 * The encoding format of the fde_count field. A value of
72 * DW_EH_PE_omit indicates the binary search table is not
73 * present.
74 *
75 * table_enc
76 *
77 * The encoding format of the entries in the binary search
78 * table. A value of DW_EH_PE_omit indicates the binary search
79 * table is not present. For shared libraries the encoding
80 * must be DW_EH_PE_sdata4|DW_EH_PE_pcrel or
81 * DW_EH_PE_sdata4|DW_EH_PE_datarel.
82 *
83 *
84 * eh_frame_ptr
85 *
86 * The encoded value of the pointer to the start of the
87 * .eh_frame section.
88 *
89 * fde_count
90 *
91 * The encoded value of the count of entries in the binary
92 * search table.
93 *
94 * binary search table
95 *
96 * A binary search table containing fde_count entries. Each
97 * entry of the table consist of two encoded values, the
98 * initial location of the function to which an FDE applies,
99 * and the address of the FDE. The entries are sorted in an
100 * increasing order by the initial location value.
101 *
102 */
103
104
105 /*
106 * EH_FRAME sections
107 * =================
108 *
109 * The call frame information needed for unwinding the stack is output in
110 * an ELF section(s) of type SHT_AMD64_UNWIND (amd64) or SHT_PROGBITS (other).
111 * In the simplest case there will be one such section per object file and it
112 * will be named ".eh_frame". An .eh_frame section consists of one or more
113 * subsections. Each subsection contains a CIE (Common Information Entry)
114 * followed by varying number of FDEs (Frame Descriptor Entry). A FDE
115 * corresponds to an explicit or compiler generated function in a
116 * compilation unit, all FDEs can access the CIE that begins their
117 * subsection for data.
118 *
119 * If an object file contains C++ template instantiations, there shall be
120 * a separate CIE immediately preceding each FDE corresponding to an
121 * instantiation.
122 *
123 * Using the preferred encoding specified below, the .eh_frame section can
124 * be entirely resolved at link time and thus can become part of the
125 * text segment.
126 *
127 * .eh_frame Section Layout
128 * ------------------------
129 *
130 * EH_PE encoding below refers to the pointer encoding as specified in the
131 * enhanced LSB Chapter 7 for Eh_Frame_Hdr.
132 *
133 * Common Information Entry (CIE)
134 * ------------------------------
135 * CIE has the following format:
136 *
137 * Length
138 * in
139 * Field Byte Description
140 * ----- ------ -----------
141 * 1. Length 4 Length of CIE (not including
142 * this 4-byte field).
143 *
144 * 2. CIE id 4 Value Zero (0) for .eh_frame
145 * (used to distinguish CIEs and
146 * FDEs when scanning the section)
147 *
148 * 3. Version 1 Value One (1)
149 *
150 * 4. CIE Augmentation string Null-terminated string with legal
151 * values being "" or 'z' optionally
152 * followed by single occurrences of
153 * 'P', 'L', or 'R' in any order.
154 * String The presence of character(s) in the
155 * string dictates the content of
156 * field 8, the Augmentation Section.
157 * Each character has one or two
158 * associated operands in the AS.
159 * Operand order depends on
160 * position in the string ('z' must
161 * be first).
162 *
163 * 5. Code Align Factor uleb128 To be multiplied with the
164 * "Advance Location" instructions in
165 * the Call Frame Instructions
166 *
167 * 6. Data Align Factor sleb128 To be multiplied with all offset
168 * in the Call Frame Instructions
169 *
170 * 7. Ret Address Reg 1 A "virtual" register representation
171 * of the return address. In Dwarf V2,
172 * this is a byte, otherwise it is
173 * uleb128. It is a byte in gcc 3.3.x
174 *
175 * 8. Optional CIE varying Present if Augmentation String in
176 * Augmentation Section field 4 is not 0.
177 *
178 * z:
179 * size uleb128 Length of the remainder of the
180 * Augmentation Section
181 *
182 * P:
183 * personality_enc 1 Encoding specifier - preferred
184 * value is a pc-relative, signed
185 * 4-byte
186 *
187 *
188 * personality routine (encoded) Encoded pointer to personality
189 * routine (actually to the PLT
190 * entry for the personality
191 * routine)
192 * R:
193 * code_enc 1 Non-default encoding for the
194 * code-pointers (FDE members
195 * "initial_location" and "address_range"
196 * and the operand for DW_CFA_set_loc)
197 * - preferred value is pc-relative,
198 * signed 4-byte.
199 * L:
200 * lsda_enc 1 FDE augmentation bodies may contain
201 * LSDA pointers. If so they are
202 * encoded as specified here -
203 * preferred value is pc-relative,
204 * signed 4-byte possibly indirect
205 * thru a GOT entry.
206 *
207 *
208 * 9. Optional Call Frame varying
209 * Instructions
210 *
211 * The size of the optional call frame instruction area must be computed
212 * based on the overall size and the offset reached while scanning the
213 * preceding fields of the CIE.
214 *
215 *
216 * Frame Descriptor Entry (FDE)
217 * ----------------------------
218 * FDE has the following format:
219 *
220 * Length
221 * in
222 * Field Byte Description
223 * ----- ------ -----------
224 * 1. Length 4 Length of remainder of this FDE
225 *
226 * 2. CIE Pointer 4 Distance from this field to the
227 * nearest preceding CIE
228 * (uthe value is subtracted from the
229 * current address). This value
230 * can never be zero and thus can
231 * be used to distinguish CIE's and
232 * FDE's when scanning the
233 * .eh_frame section
234 *
235 * 3. Initial Location varying Reference to the function code
236 * corresponding to this FDE.
237 * If 'R' is missing from the CIE
238 * Augmentation String, the field is an
239 * 8-byte absolute pointer. Otherwise,
240 * the corresponding EH_PE encoding in the
241 * CIE Augmentation Section is used to
242 * interpret the reference.
243 *
244 * 4. Address Range varying Size of the function code corresponding
245 * to this FDE.
246 * If 'R' is missing from the CIE
247 * Augmentation String, the field is an
248 * 8-byte unsigned number. Otherwise,
249 * the size is determined by the
250 * corresponding EH_PE encoding in the
251 * CIE Augmentation Section (the
252 * value is always absolute).
253 *
254 * 5. Optional FDE varying present if CIE augmentation
255 * Augmentation Section string is non-empty.
256 *
257 *
258 * 'z':
259 * length uleb128 length of the remainder of the
260 * FDE augmentation section
261 *
262 *
263 * 'L' (and length > 0):
264 * LSDA varying LSDA pointer, encoded in the
265 * format specified by the
266 * corresponding operand in the CIE's
267 * augmentation body.
268 *
269 * 6. Optional Call varying
270 * Frame Instructions
271 *
272 * The size of the optional call frame instruction area must be computed
273 * based on the overall size and the offset reached while scanning the
274 * preceding fields of the FDE.
275 *
276 * The overall size of a .eh_frame section is given in the ELF section
277 * header. The only way to determine the number of entries is to scan
278 * the section till the end and count.
279 *
280 */
281
282
283
284
285 static uint_t
286 extract_uint(const uchar_t *data, uint64_t *ndx, int do_swap)
287 {
288 uint_t r;
289 uchar_t *p = (uchar_t *)&r;
290
291 data += *ndx;
292 if (do_swap)
293 UL_ASSIGN_BSWAP_WORD(p, data);
294 else
295 UL_ASSIGN_WORD(p, data);
296
297 (*ndx) += 4;
298 return (r);
299 }
300
301 /*
302 * Create an unwind header (.eh_frame_hdr) output section.
303 * The section is created and space reserved, but the data
304 * is not copied into place. That is done by a later call
305 * to ld_unwind_populate(), after active relocations have been
306 * processed.
307 *
308 * When GNU linkonce processing is in effect, we can end up in a situation
309 * where the FDEs related to discarded sections remain in the eh_frame
310 * section. Ideally, we would remove these dead entries from eh_frame.
311 * However, that optimization has not yet been implemented. In the current
312 * implementation, the number of dead FDEs cannot be determined until
313 * active relocations are processed, and that processing follows the
314 * call to this function. This means that we are unable to detect dead FDEs
315 * here, and the section created by this routine is sized for maximum case
316 * where all FDEs are valid.
317 */
318 uintptr_t
319 ld_unwind_make_hdr(Ofl_desc *ofl)
320 {
321 int bswap = (ofl->ofl_flags1 & FLG_OF1_ENCDIFF) != 0;
322 Shdr *shdr;
323 Elf_Data *elfdata;
324 Is_desc *isp;
325 size_t size;
326 Xword fde_cnt;
327 Aliste idx1;
328 Os_desc *osp;
329
330 /*
331 * we only build a unwind header if we have
332 * some unwind information in the file.
333 */
334 if (ofl->ofl_unwind == NULL)
335 return (1);
336
337 /*
338 * Allocate and initialize the Elf_Data structure.
339 */
340 if ((elfdata = libld_calloc(sizeof (Elf_Data), 1)) == NULL)
341 return (S_ERROR);
342 elfdata->d_type = ELF_T_BYTE;
343 elfdata->d_align = ld_targ.t_m.m_word_align;
344 elfdata->d_version = ofl->ofl_dehdr->e_version;
345
346 /*
347 * Allocate and initialize the Shdr structure.
348 */
349 if ((shdr = libld_calloc(sizeof (Shdr), 1)) == NULL)
350 return (S_ERROR);
351 shdr->sh_type = ld_targ.t_m.m_sht_unwind;
352 shdr->sh_flags = SHF_ALLOC;
353 shdr->sh_addralign = ld_targ.t_m.m_word_align;
354 shdr->sh_entsize = 0;
355
356 /*
357 * Allocate and initialize the Is_desc structure.
358 */
359 if ((isp = libld_calloc(1, sizeof (Is_desc))) == NULL)
360 return (S_ERROR);
361 isp->is_name = MSG_ORIG(MSG_SCN_UNWINDHDR);
362 isp->is_shdr = shdr;
363 isp->is_indata = elfdata;
364
365 if ((ofl->ofl_unwindhdr = ld_place_section(ofl, isp, NULL,
366 ld_targ.t_id.id_unwindhdr, NULL)) == (Os_desc *)S_ERROR)
367 return (S_ERROR);
368
369 /*
370 * Scan through all of the input Frame information, counting each FDE
371 * that requires an index. Each fde_entry gets a corresponding entry
372 * in the binary search table.
373 */
374 fde_cnt = 0;
375 for (APLIST_TRAVERSE(ofl->ofl_unwind, idx1, osp)) {
376 Aliste idx2;
377 int os_isdescs_idx;
378
379 OS_ISDESCS_TRAVERSE(os_isdescs_idx, osp, idx2, isp) {
380 uchar_t *data;
381 uint64_t off = 0;
382
383 data = isp->is_indata->d_buf;
384 size = isp->is_indata->d_size;
385
386 while (off < size) {
387 uint_t length, id;
388 uint64_t ndx = 0;
389
390 /*
391 * Extract length in lsb format. A zero length
392 * indicates that this CIE is a terminator and
393 * that processing for unwind information is
394 * complete.
395 */
396 length = extract_uint(data + off, &ndx, bswap);
397 if (length == 0)
398 break;
399
400 /*
401 * Extract CIE id in lsb format.
402 */
403 id = extract_uint(data + off, &ndx, bswap);
404
405 /*
406 * A CIE record has a id of '0', otherwise
407 * this is a FDE entry and the 'id' is the
408 * CIE pointer.
409 */
410 if (id == 0) {
411 uint_t cieversion;
412 /*
413 * The only CIE version supported
414 * is '1' - quick sanity check
415 * here.
416 */
417 cieversion = data[off + ndx];
418 ndx += 1;
419 /* BEGIN CSTYLED */
420 if (cieversion != 1) {
421 ld_eprintf(ofl, ERR_FATAL,
422 MSG_INTL(MSG_UNW_BADCIEVERS),
423 isp->is_file->ifl_name,
424 isp->is_name, off);
425 return (S_ERROR);
426 }
427 /* END CSTYLED */
428 } else {
429 fde_cnt++;
430 }
431 off += length + 4;
432 }
433 }
434 }
435
436 /*
437 * section size:
438 * byte version +1
439 * byte eh_frame_ptr_enc +1
440 * byte fde_count_enc +1
441 * byte table_enc +1
442 * 4 bytes eh_frame_ptr +4
443 * 4 bytes fde_count +4
444 * [4 bytes] [4bytes] * fde_count ...
445 */
446 size = 12 + (8 * fde_cnt);
447
448 if ((elfdata->d_buf = libld_calloc(size, 1)) == NULL)
449 return (S_ERROR);
450 elfdata->d_size = size;
451 shdr->sh_size = (Xword)size;
452
453 return (1);
454 }
455
456 /*
457 * the comparator function needs to calculate
458 * the actual 'initloc' of a bintab entry - to
459 * do this we initialize the following global to point
460 * to it.
461 */
462 static Addr framehdr_addr;
463
464 static int
465 bintabcompare(const void *p1, const void *p2)
466 {
467 uint_t *bintab1, *bintab2;
468 uint_t ent1, ent2;
469
470 bintab1 = (uint_t *)p1;
471 bintab2 = (uint_t *)p2;
472
473 assert(bintab1 != 0);
474 assert(bintab2 != 0);
475
476 ent1 = *bintab1 + framehdr_addr;
477 ent2 = *bintab2 + framehdr_addr;
478
479 if (ent1 > ent2)
480 return (1);
481 if (ent1 < ent2)
482 return (-1);
483 return (0);
484 }
485
486 uintptr_t
487 ld_unwind_populate_hdr(Ofl_desc *ofl)
488 {
489 uchar_t *hdrdata;
490 uint_t *binarytable;
491 uint_t hdroff;
492 Aliste idx;
493 Addr hdraddr;
494 Os_desc *hdrosp;
495 Os_desc *osp;
496 Os_desc *first_unwind;
497 uint_t fde_count;
498 uint_t *uint_ptr;
499 int bswap = (ofl->ofl_flags1 & FLG_OF1_ENCDIFF) != 0;
500
501 /*
502 * Are we building the unwind hdr?
503 */
504 if ((hdrosp = ofl->ofl_unwindhdr) == 0)
505 return (1);
506
507 hdrdata = hdrosp->os_outdata->d_buf;
508 hdraddr = hdrosp->os_shdr->sh_addr;
509 hdroff = 0;
510
511 /*
512 * version == 1
513 */
514 hdrdata[hdroff++] = 1;
515 /*
516 * The encodings are:
517 *
518 * eh_frameptr_enc sdata4 | pcrel
519 * fde_count_enc udata4
520 * table_enc sdata4 | datarel
521 */
522 hdrdata[hdroff++] = DW_EH_PE_sdata4 | DW_EH_PE_pcrel;
523 hdrdata[hdroff++] = DW_EH_PE_udata4;
524 hdrdata[hdroff++] = DW_EH_PE_sdata4 | DW_EH_PE_datarel;
525
526 /*
527 * Header Offsets
528 * -----------------------------------
529 * byte version +1
530 * byte eh_frame_ptr_enc +1
531 * byte fde_count_enc +1
532 * byte table_enc +1
533 * 4 bytes eh_frame_ptr +4
534 * 4 bytes fde_count +4
535 */
536 /* LINTED */
537 binarytable = (uint_t *)(hdrdata + 12);
538 first_unwind = 0;
539 fde_count = 0;
540
541 for (APLIST_TRAVERSE(ofl->ofl_unwind, idx, osp)) {
542 uchar_t *data;
543 size_t size;
544 uint64_t off = 0;
545 uint_t cieRflag = 0, ciePflag = 0;
546 Shdr *shdr;
547
548 /*
549 * remember first UNWIND section to
550 * point to in the frame_ptr entry.
551 */
552 if (first_unwind == 0)
553 first_unwind = osp;
554
555 data = osp->os_outdata->d_buf;
556 shdr = osp->os_shdr;
557 size = shdr->sh_size;
558
559 while (off < size) {
560 uint_t length, id;
561 uint64_t ndx = 0;
562
563 /*
564 * Extract length in lsb format. A zero length
565 * indicates that this CIE is a terminator and that
566 * processing of unwind information is complete.
567 */
568 length = extract_uint(data + off, &ndx, bswap);
569 if (length == 0)
570 goto done;
571
572 /*
573 * Extract CIE id in lsb format.
574 */
575 id = extract_uint(data + off, &ndx, bswap);
576
577 /*
578 * A CIE record has a id of '0'; otherwise
579 * this is a FDE entry and the 'id' is the
580 * CIE pointer.
581 */
582 if (id == 0) {
583 char *cieaugstr;
584 uint_t cieaugndx;
585
586 ciePflag = 0;
587 cieRflag = 0;
588 /*
589 * We need to drill through the CIE
590 * to find the Rflag. It's the Rflag
591 * which describes how the FDE code-pointers
592 * are encoded.
593 */
594
595 /*
596 * burn through version
597 */
598 ndx++;
599
600 /*
601 * augstr
602 */
603 cieaugstr = (char *)(&data[off + ndx]);
604 ndx += strlen(cieaugstr) + 1;
605
606 /*
607 * calign & dalign
608 */
609 (void) uleb_extract(&data[off], &ndx);
610 (void) sleb_extract(&data[off], &ndx);
611
612 /*
613 * retreg
614 */
615 ndx++;
616
617 /*
618 * we walk through the augmentation
619 * section now looking for the Rflag
620 */
621 for (cieaugndx = 0; cieaugstr[cieaugndx];
622 cieaugndx++) {
623 /* BEGIN CSTYLED */
624 switch (cieaugstr[cieaugndx]) {
625 case 'z':
626 /* size */
627 (void) uleb_extract(&data[off],
628 &ndx);
629 break;
630 case 'P':
631 /* personality */
632 ciePflag = data[off + ndx];
633 ndx++;
634 /*
635 * Just need to extract the
636 * value to move on to the next
637 * field.
638 */
639 (void) dwarf_ehe_extract(
640 &data[off + ndx],
641 &ndx, ciePflag,
642 ofl->ofl_dehdr->e_ident, B_FALSE,
643 shdr->sh_addr, off + ndx, 0);
644 break;
645 case 'R':
646 /* code encoding */
647 cieRflag = data[off + ndx];
648 ndx++;
649 break;
650 case 'L':
651 /* lsda encoding */
652 ndx++;
653 break;
654 }
655 /* END CSTYLED */
656 }
657 } else {
658 uint_t bintabndx;
659 uint64_t initloc;
660 uint64_t fdeaddr;
661 uint64_t gotaddr = 0;
662
663 if (ofl->ofl_osgot != NULL)
664 gotaddr =
665 ofl->ofl_osgot->os_shdr->sh_addr;
666
667 initloc = dwarf_ehe_extract(&data[off],
668 &ndx, cieRflag, ofl->ofl_dehdr->e_ident,
669 B_FALSE,
670 shdr->sh_addr, off + ndx,
671 gotaddr);
672
673 /*
674 * Ignore FDEs with initloc set to 0.
675 * initloc will not be 0 unless this FDE was
676 * abandoned due to GNU linkonce processing.
677 * The 0 value occurs because we don't resolve
678 * sloppy relocations for unwind header target
679 * sections.
680 */
681 if (initloc != 0) {
682 bintabndx = fde_count * 2;
683 fde_count++;
684
685 /*
686 * FDEaddr is adjusted
687 * to account for the length & id which
688 * have already been consumed.
689 */
690 fdeaddr = shdr->sh_addr + off;
691
692 binarytable[bintabndx] =
693 (uint_t)(initloc - hdraddr);
694 binarytable[bintabndx + 1] =
695 (uint_t)(fdeaddr - hdraddr);
696 }
697 }
698
699 /*
700 * the length does not include the length
701 * itself - so account for that too.
702 */
703 off += length + 4;
704 }
705 }
706
707 done:
708 /*
709 * Do a quicksort on the binary table. If this is a cross
710 * link from a system with the opposite byte order, xlate
711 * the resulting values into LSB order.
712 */
713 framehdr_addr = hdraddr;
714 qsort((void *)binarytable, (size_t)fde_count,
715 (size_t)(sizeof (uint_t) * 2), bintabcompare);
716 if (bswap) {
717 uint_t *btable = binarytable;
718 uint_t cnt;
719
720 for (cnt = fde_count * 2; cnt-- > 0; btable++)
721 *btable = ld_bswap_Word(*btable);
722 }
723
724 /*
725 * Fill in:
726 * first_frame_ptr
727 * fde_count
728 */
729 hdroff = 4;
730 /* LINTED */
731 uint_ptr = (uint_t *)(&hdrdata[hdroff]);
732 *uint_ptr = first_unwind->os_shdr->sh_addr -
733 (hdrosp->os_shdr->sh_addr + hdroff);
734 if (bswap)
735 *uint_ptr = ld_bswap_Word(*uint_ptr);
736
737 hdroff += 4;
738 /* LINTED */
739 uint_ptr = (uint_t *)&hdrdata[hdroff];
740 *uint_ptr = fde_count;
741 if (bswap)
742 *uint_ptr = ld_bswap_Word(*uint_ptr);
743
744 /*
745 * If relaxed relocations are active, then there is a chance
746 * that we didn't use all the space reserved for this section.
747 * For details, see the note at head of ld_unwind_make_hdr() above.
748 *
749 * Find the PT_SUNW_UNWIND program header, and change the size values
750 * to the size of the subset of the section that was actually used.
751 */
752 if (ofl->ofl_flags1 & FLG_OF1_RLXREL) {
753 Word phnum = ofl->ofl_nehdr->e_phnum;
754 Phdr *phdr = ofl->ofl_phdr;
755
756 for (; phnum-- > 0; phdr++) {
757 if (phdr->p_type == PT_SUNW_UNWIND) {
758 phdr->p_memsz = 12 + (8 * fde_count);
759 phdr->p_filesz = phdr->p_memsz;
760 break;
761 }
762 }
763 }
764
765 return (1);
766 }
767
768 /*
769 * Append an .eh_frame section to our output list if not already present.
770 *
771 * Usually, there is a single .eh_frame output section. However, there can
772 * be more if there are incompatible section flags on incoming sections.
773 * If this does happen, the frame_ptr field of the eh_frame_hdr section
774 * will point at the base of the first output section, and the other
775 * sections will not be accessible via frame_ptr. However, the .eh_frame_hdr
776 * will be able to access all the data in the different .eh_frame sections,
777 * because the entries in sorted table are all encoded as DW_EH_PE_datarel.
778 */
779 uintptr_t
780 ld_unwind_register(Os_desc *osp, Ofl_desc * ofl)
781 {
782 Aliste idx;
783 Os_desc *_osp;
784 /*
785 * Check to see if this output section is already
786 * on the list.
787 */
788 for (APLIST_TRAVERSE(ofl->ofl_unwind, idx, _osp))
789 if (osp == _osp)
790 return (1);
791
792 /*
793 * Append output section to unwind list
794 */
795 if (aplist_append(&ofl->ofl_unwind, osp, AL_CNT_OFL_UNWIND) == NULL)
796 return (S_ERROR);
797
798 return (1);
799 }