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 * Copyright 2014 Nexenta Systems, Inc. 25 */ 26 27 #include <string.h> 28 #include <stdio.h> 29 #include <sys/types.h> 30 #include <sgs.h> 31 #include <debug.h> 32 #include <_libld.h> 33 #include <dwarf.h> 34 #include <stdlib.h> 35 36 /* 37 * A EH_FRAME_HDR consists of the following: 38 * 39 * Encoding Field 40 * -------------------------------- 41 * unsigned byte version 42 * unsigned byte eh_frame_ptr_enc 43 * unsigned byte fde_count_enc 44 * unsigned byte table_enc 45 * encoded eh_frame_ptr 46 * encoded fde_count 47 * [ binary search table ] 48 * 49 * The binary search table entries each consists of: 50 * 51 * encoded initial_func_loc 52 * encoded FDE_address 53 * 54 * The entries in the binary search table are sorted 55 * in a increasing order by the initial location. 56 * 57 * 58 * version 59 * 60 * Version of the .eh_frame_hdr format. This value shall be 1. 61 * 62 * eh_frame_ptr_enc 63 * 64 * The encoding format of the eh_frame_ptr field. For shared 65 * libraries the encoding must be 66 * DW_EH_PE_sdata4|DW_EH_PE_pcrel or 67 * DW_EH_PE_sdata4|DW_EH_PE_datarel. 68 * 69 * 70 * fde_count_enc 71 * 72 * The encoding format of the fde_count field. A value of 73 * DW_EH_PE_omit indicates the binary search table is not 74 * present. 75 * 76 * table_enc 77 * 78 * The encoding format of the entries in the binary search 79 * table. A value of DW_EH_PE_omit indicates the binary search 80 * table is not present. For shared libraries the encoding 81 * must be DW_EH_PE_sdata4|DW_EH_PE_pcrel or 82 * DW_EH_PE_sdata4|DW_EH_PE_datarel. 83 * 84 * 85 * eh_frame_ptr 86 * 87 * The encoded value of the pointer to the start of the 88 * .eh_frame section. 89 * 90 * fde_count 91 * 92 * The encoded value of the count of entries in the binary 93 * search table. 94 * 95 * binary search table 96 * 97 * A binary search table containing fde_count entries. Each 98 * entry of the table consist of two encoded values, the 99 * initial location of the function to which an FDE applies, 100 * and the address of the FDE. The entries are sorted in an 101 * increasing order by the initial location value. 102 * 103 */ 104 105 106 /* 107 * EH_FRAME sections 108 * ================= 109 * 110 * The call frame information needed for unwinding the stack is output in 111 * an ELF section(s) of type SHT_AMD64_UNWIND (amd64) or SHT_PROGBITS (other). 112 * In the simplest case there will be one such section per object file and it 113 * will be named ".eh_frame". An .eh_frame section consists of one or more 114 * subsections. Each subsection contains a CIE (Common Information Entry) 115 * followed by varying number of FDEs (Frame Descriptor Entry). A FDE 116 * corresponds to an explicit or compiler generated function in a 117 * compilation unit, all FDEs can access the CIE that begins their 118 * subsection for data. 119 * 120 * If an object file contains C++ template instantiations, there shall be 121 * a separate CIE immediately preceding each FDE corresponding to an 122 * instantiation. 123 * 124 * Using the preferred encoding specified below, the .eh_frame section can 125 * be entirely resolved at link time and thus can become part of the 126 * text segment. 127 * 128 * .eh_frame Section Layout 129 * ------------------------ 130 * 131 * EH_PE encoding below refers to the pointer encoding as specified in the 132 * enhanced LSB Chapter 7 for Eh_Frame_Hdr. 133 * 134 * Common Information Entry (CIE) 135 * ------------------------------ 136 * CIE has the following format: 137 * 138 * Length 139 * in 140 * Field Byte Description 141 * ----- ------ ----------- 142 * 1. Length 4 Length of CIE (not including 143 * this 4-byte field). 144 * 145 * 2. CIE id 4 Value Zero (0) for .eh_frame 146 * (used to distinguish CIEs and 147 * FDEs when scanning the section) 148 * 149 * 3. Version 1 Value One (1) 150 * 151 * 4. CIE Augmentation string Null-terminated string with legal 152 * values being "" or 'z' optionally 153 * followed by single occurrences of 154 * 'P', 'L', or 'R' in any order. 155 * String The presence of character(s) in the 156 * string dictates the content of 157 * field 8, the Augmentation Section. 158 * Each character has one or two 159 * associated operands in the AS. 160 * Operand order depends on 161 * position in the string ('z' must 162 * be first). 163 * 164 * 5. Code Align Factor uleb128 To be multiplied with the 165 * "Advance Location" instructions in 166 * the Call Frame Instructions 167 * 168 * 6. Data Align Factor sleb128 To be multiplied with all offset 169 * in the Call Frame Instructions 170 * 171 * 7. Ret Address Reg 1 A "virtual" register representation 172 * of the return address. In Dwarf V2, 173 * this is a byte, otherwise it is 174 * uleb128. It is a byte in gcc 3.3.x 175 * 176 * 8. Optional CIE varying Present if Augmentation String in 177 * Augmentation Section field 4 is not 0. 178 * 179 * z: 180 * size uleb128 Length of the remainder of the 181 * Augmentation Section 182 * 183 * P: 184 * personality_enc 1 Encoding specifier - preferred 185 * value is a pc-relative, signed 186 * 4-byte 187 * 188 * 189 * personality routine (encoded) Encoded pointer to personality 190 * routine (actually to the PLT 191 * entry for the personality 192 * routine) 193 * R: 194 * code_enc 1 Non-default encoding for the 195 * code-pointers (FDE members 196 * "initial_location" and "address_range" 197 * and the operand for DW_CFA_set_loc) 198 * - preferred value is pc-relative, 199 * signed 4-byte. 200 * L: 201 * lsda_enc 1 FDE augmentation bodies may contain 202 * LSDA pointers. If so they are 203 * encoded as specified here - 204 * preferred value is pc-relative, 205 * signed 4-byte possibly indirect 206 * thru a GOT entry. 207 * 208 * 209 * 9. Optional Call Frame varying 210 * Instructions 211 * 212 * The size of the optional call frame instruction area must be computed 213 * based on the overall size and the offset reached while scanning the 214 * preceding fields of the CIE. 215 * 216 * 217 * Frame Descriptor Entry (FDE) 218 * ---------------------------- 219 * FDE has the following format: 220 * 221 * Length 222 * in 223 * Field Byte Description 224 * ----- ------ ----------- 225 * 1. Length 4 Length of remainder of this FDE 226 * 227 * 2. CIE Pointer 4 Distance from this field to the 228 * nearest preceding CIE 229 * (uthe value is subtracted from the 230 * current address). This value 231 * can never be zero and thus can 232 * be used to distinguish CIE's and 233 * FDE's when scanning the 234 * .eh_frame section 235 * 236 * 3. Initial Location varying Reference to the function code 237 * corresponding to this FDE. 238 * If 'R' is missing from the CIE 239 * Augmentation String, the field is an 240 * 8-byte absolute pointer. Otherwise, 241 * the corresponding EH_PE encoding in the 242 * CIE Augmentation Section is used to 243 * interpret the reference. 244 * 245 * 4. Address Range varying Size of the function code corresponding 246 * to this FDE. 247 * If 'R' is missing from the CIE 248 * Augmentation String, the field is an 249 * 8-byte unsigned number. Otherwise, 250 * the size is determined by the 251 * corresponding EH_PE encoding in the 252 * CIE Augmentation Section (the 253 * value is always absolute). 254 * 255 * 5. Optional FDE varying present if CIE augmentation 256 * Augmentation Section string is non-empty. 257 * 258 * 259 * 'z': 260 * length uleb128 length of the remainder of the 261 * FDE augmentation section 262 * 263 * 264 * 'L' (and length > 0): 265 * LSDA varying LSDA pointer, encoded in the 266 * format specified by the 267 * corresponding operand in the CIE's 268 * augmentation body. 269 * 270 * 6. Optional Call varying 271 * Frame Instructions 272 * 273 * The size of the optional call frame instruction area must be computed 274 * based on the overall size and the offset reached while scanning the 275 * preceding fields of the FDE. 276 * 277 * The overall size of a .eh_frame section is given in the ELF section 278 * header. The only way to determine the number of entries is to scan 279 * the section till the end and count. 280 * 281 */ 282 283 284 285 286 static uint_t 287 extract_uint(const uchar_t *data, uint64_t *ndx, int do_swap) 288 { 289 uint_t r; 290 uchar_t *p = (uchar_t *)&r; 291 292 data += *ndx; 293 if (do_swap) 294 UL_ASSIGN_BSWAP_WORD(p, data); 295 else 296 UL_ASSIGN_WORD(p, data); 297 298 (*ndx) += 4; 299 return (r); 300 } 301 302 /* 303 * Create an unwind header (.eh_frame_hdr) output section. 304 * The section is created and space reserved, but the data 305 * is not copied into place. That is done by a later call 306 * to ld_unwind_populate(), after active relocations have been 307 * processed. 308 * 309 * When GNU linkonce processing is in effect, we can end up in a situation 310 * where the FDEs related to discarded sections remain in the eh_frame 311 * section. Ideally, we would remove these dead entries from eh_frame. 312 * However, that optimization has not yet been implemented. In the current 313 * implementation, the number of dead FDEs cannot be determined until 314 * active relocations are processed, and that processing follows the 315 * call to this function. This means that we are unable to detect dead FDEs 316 * here, and the section created by this routine is sized for maximum case 317 * where all FDEs are valid. 318 */ 319 uintptr_t 320 ld_unwind_make_hdr(Ofl_desc *ofl) 321 { 322 int bswap = (ofl->ofl_flags1 & FLG_OF1_ENCDIFF) != 0; 323 Shdr *shdr; 324 Elf_Data *elfdata; 325 Is_desc *isp; 326 size_t size; 327 Xword fde_cnt; 328 Aliste idx1; 329 Os_desc *osp; 330 331 /* 332 * we only build a unwind header if we have 333 * some unwind information in the file. 334 */ 335 if (ofl->ofl_unwind == NULL) 336 return (1); 337 338 /* 339 * Allocate and initialize the Elf_Data structure. 340 */ 341 if ((elfdata = libld_calloc(sizeof (Elf_Data), 1)) == NULL) 342 return (S_ERROR); 343 elfdata->d_type = ELF_T_BYTE; 344 elfdata->d_align = ld_targ.t_m.m_word_align; 345 elfdata->d_version = ofl->ofl_dehdr->e_version; 346 347 /* 348 * Allocate and initialize the Shdr structure. 349 */ 350 if ((shdr = libld_calloc(sizeof (Shdr), 1)) == NULL) 351 return (S_ERROR); 352 shdr->sh_type = ld_targ.t_m.m_sht_unwind; 353 shdr->sh_flags = SHF_ALLOC; 354 shdr->sh_addralign = ld_targ.t_m.m_word_align; 355 shdr->sh_entsize = 0; 356 357 /* 358 * Allocate and initialize the Is_desc structure. 359 */ 360 if ((isp = libld_calloc(1, sizeof (Is_desc))) == NULL) 361 return (S_ERROR); 362 isp->is_name = MSG_ORIG(MSG_SCN_UNWINDHDR); 363 isp->is_shdr = shdr; 364 isp->is_indata = elfdata; 365 366 if ((ofl->ofl_unwindhdr = ld_place_section(ofl, isp, NULL, 367 ld_targ.t_id.id_unwindhdr, NULL)) == (Os_desc *)S_ERROR) 368 return (S_ERROR); 369 370 /* 371 * Scan through all of the input Frame information, counting each FDE 372 * that requires an index. Each fde_entry gets a corresponding entry 373 * in the binary search table. 374 */ 375 fde_cnt = 0; 376 for (APLIST_TRAVERSE(ofl->ofl_unwind, idx1, osp)) { 377 Aliste idx2; 378 int os_isdescs_idx; 379 380 OS_ISDESCS_TRAVERSE(os_isdescs_idx, osp, idx2, isp) { 381 uchar_t *data; 382 uint64_t off = 0; 383 384 data = isp->is_indata->d_buf; 385 size = isp->is_indata->d_size; 386 387 while (off < size) { 388 uint_t length, id; 389 uint64_t ndx = 0; 390 391 /* 392 * Extract length in lsb format. A zero length 393 * indicates that this CIE is a terminator and 394 * that processing for unwind information is 395 * complete. 396 */ 397 length = extract_uint(data + off, &ndx, bswap); 398 if (length == 0) 399 break; 400 401 /* 402 * Extract CIE id in lsb format. 403 */ 404 id = extract_uint(data + off, &ndx, bswap); 405 406 /* 407 * A CIE record has a id of '0', otherwise 408 * this is a FDE entry and the 'id' is the 409 * CIE pointer. 410 */ 411 if (id == 0) { 412 uint_t cieversion; 413 cieversion = data[off + ndx]; 414 ndx += 1; 415 /* BEGIN CSTYLED */ 416 if (cieversion != 1 && cieversion != 3) { 417 ld_eprintf(ofl, ERR_FATAL, 418 MSG_INTL(MSG_UNW_BADCIEVERS), 419 isp->is_file->ifl_name, 420 isp->is_name, off); 421 return (S_ERROR); 422 } 423 /* END CSTYLED */ 424 } else { 425 fde_cnt++; 426 } 427 off += length + 4; 428 } 429 } 430 } 431 432 /* 433 * section size: 434 * byte version +1 435 * byte eh_frame_ptr_enc +1 436 * byte fde_count_enc +1 437 * byte table_enc +1 438 * 4 bytes eh_frame_ptr +4 439 * 4 bytes fde_count +4 440 * [4 bytes] [4bytes] * fde_count ... 441 */ 442 size = 12 + (8 * fde_cnt); 443 444 if ((elfdata->d_buf = libld_calloc(size, 1)) == NULL) 445 return (S_ERROR); 446 elfdata->d_size = size; 447 shdr->sh_size = (Xword)size; 448 449 return (1); 450 } 451 452 /* 453 * the comparator function needs to calculate 454 * the actual 'initloc' of a bintab entry - to 455 * do this we initialize the following global to point 456 * to it. 457 */ 458 static Addr framehdr_addr; 459 460 static int 461 bintabcompare(const void *p1, const void *p2) 462 { 463 uint_t *bintab1, *bintab2; 464 uint_t ent1, ent2; 465 466 bintab1 = (uint_t *)p1; 467 bintab2 = (uint_t *)p2; 468 469 assert(bintab1 != 0); 470 assert(bintab2 != 0); 471 472 ent1 = *bintab1 + framehdr_addr; 473 ent2 = *bintab2 + framehdr_addr; 474 475 if (ent1 > ent2) 476 return (1); 477 if (ent1 < ent2) 478 return (-1); 479 return (0); 480 } 481 482 uintptr_t 483 ld_unwind_populate_hdr(Ofl_desc *ofl) 484 { 485 uchar_t *hdrdata; 486 uint_t *binarytable; 487 uint_t hdroff; 488 Aliste idx; 489 Addr hdraddr; 490 Os_desc *hdrosp; 491 Os_desc *osp; 492 Os_desc *first_unwind; 493 uint_t fde_count; 494 uint_t *uint_ptr; 495 int bswap = (ofl->ofl_flags1 & FLG_OF1_ENCDIFF) != 0; 496 497 /* 498 * Are we building the unwind hdr? 499 */ 500 if ((hdrosp = ofl->ofl_unwindhdr) == 0) 501 return (1); 502 503 hdrdata = hdrosp->os_outdata->d_buf; 504 hdraddr = hdrosp->os_shdr->sh_addr; 505 hdroff = 0; 506 507 /* 508 * version == 1 509 */ 510 hdrdata[hdroff++] = 1; 511 /* 512 * The encodings are: 513 * 514 * eh_frameptr_enc sdata4 | pcrel 515 * fde_count_enc udata4 516 * table_enc sdata4 | datarel 517 */ 518 hdrdata[hdroff++] = DW_EH_PE_sdata4 | DW_EH_PE_pcrel; 519 hdrdata[hdroff++] = DW_EH_PE_udata4; 520 hdrdata[hdroff++] = DW_EH_PE_sdata4 | DW_EH_PE_datarel; 521 522 /* 523 * Header Offsets 524 * ----------------------------------- 525 * byte version +1 526 * byte eh_frame_ptr_enc +1 527 * byte fde_count_enc +1 528 * byte table_enc +1 529 * 4 bytes eh_frame_ptr +4 530 * 4 bytes fde_count +4 531 */ 532 /* LINTED */ 533 binarytable = (uint_t *)(hdrdata + 12); 534 first_unwind = 0; 535 fde_count = 0; 536 537 for (APLIST_TRAVERSE(ofl->ofl_unwind, idx, osp)) { 538 uchar_t *data; 539 size_t size; 540 uint64_t off = 0; 541 uint_t cieRflag = 0, ciePflag = 0; 542 Shdr *shdr; 543 544 /* 545 * remember first UNWIND section to 546 * point to in the frame_ptr entry. 547 */ 548 if (first_unwind == 0) 549 first_unwind = osp; 550 551 data = osp->os_outdata->d_buf; 552 shdr = osp->os_shdr; 553 size = shdr->sh_size; 554 555 while (off < size) { 556 uint_t length, id; 557 uint64_t ndx = 0; 558 559 /* 560 * Extract length in lsb format. A zero length 561 * indicates that this CIE is a terminator and that 562 * processing of unwind information is complete. 563 */ 564 length = extract_uint(data + off, &ndx, bswap); 565 if (length == 0) 566 goto done; 567 568 /* 569 * Extract CIE id in lsb format. 570 */ 571 id = extract_uint(data + off, &ndx, bswap); 572 573 /* 574 * A CIE record has a id of '0'; otherwise 575 * this is a FDE entry and the 'id' is the 576 * CIE pointer. 577 */ 578 if (id == 0) { 579 char *cieaugstr; 580 uint_t cieaugndx; 581 uint_t cieversion; 582 583 ciePflag = 0; 584 cieRflag = 0; 585 /* 586 * We need to drill through the CIE 587 * to find the Rflag. It's the Rflag 588 * which describes how the FDE code-pointers 589 * are encoded. 590 */ 591 592 cieversion = data[off + ndx]; 593 ndx += 1; 594 595 /* 596 * augstr 597 */ 598 cieaugstr = (char *)(&data[off + ndx]); 599 ndx += strlen(cieaugstr) + 1; 600 601 /* 602 * calign & dalign 603 */ 604 (void) uleb_extract(&data[off], &ndx); 605 (void) sleb_extract(&data[off], &ndx); 606 607 /* 608 * retreg 609 */ 610 if (cieversion == 1) 611 ndx++; 612 else 613 (void) uleb_extract(&data[off], &ndx); 614 /* 615 * we walk through the augmentation 616 * section now looking for the Rflag 617 */ 618 for (cieaugndx = 0; cieaugstr[cieaugndx]; 619 cieaugndx++) { 620 /* BEGIN CSTYLED */ 621 switch (cieaugstr[cieaugndx]) { 622 case 'z': 623 /* size */ 624 (void) uleb_extract(&data[off], 625 &ndx); 626 break; 627 case 'P': 628 /* personality */ 629 ciePflag = data[off + ndx]; 630 ndx++; 631 /* 632 * Just need to extract the 633 * value to move on to the next 634 * field. 635 */ 636 (void) dwarf_ehe_extract( 637 &data[off + ndx], 638 &ndx, ciePflag, 639 ofl->ofl_dehdr->e_ident, B_FALSE, 640 shdr->sh_addr, off + ndx, 0); 641 break; 642 case 'R': 643 /* code encoding */ 644 cieRflag = data[off + ndx]; 645 ndx++; 646 break; 647 case 'L': 648 /* lsda encoding */ 649 ndx++; 650 break; 651 } 652 /* END CSTYLED */ 653 } 654 } else { 655 uint_t bintabndx; 656 uint64_t initloc; 657 uint64_t fdeaddr; 658 uint64_t gotaddr = 0; 659 660 if (ofl->ofl_osgot != NULL) 661 gotaddr = 662 ofl->ofl_osgot->os_shdr->sh_addr; 663 664 initloc = dwarf_ehe_extract(&data[off], 665 &ndx, cieRflag, ofl->ofl_dehdr->e_ident, 666 B_FALSE, 667 shdr->sh_addr, off + ndx, 668 gotaddr); 669 670 /* 671 * Ignore FDEs with initloc set to 0. 672 * initloc will not be 0 unless this FDE was 673 * abandoned due to GNU linkonce processing. 674 * The 0 value occurs because we don't resolve 675 * sloppy relocations for unwind header target 676 * sections. 677 */ 678 if (initloc != 0) { 679 bintabndx = fde_count * 2; 680 fde_count++; 681 682 /* 683 * FDEaddr is adjusted 684 * to account for the length & id which 685 * have already been consumed. 686 */ 687 fdeaddr = shdr->sh_addr + off; 688 689 binarytable[bintabndx] = 690 (uint_t)(initloc - hdraddr); 691 binarytable[bintabndx + 1] = 692 (uint_t)(fdeaddr - hdraddr); 693 } 694 } 695 696 /* 697 * the length does not include the length 698 * itself - so account for that too. 699 */ 700 off += length + 4; 701 } 702 } 703 704 done: 705 /* 706 * Do a quicksort on the binary table. If this is a cross 707 * link from a system with the opposite byte order, xlate 708 * the resulting values into LSB order. 709 */ 710 framehdr_addr = hdraddr; 711 qsort((void *)binarytable, (size_t)fde_count, 712 (size_t)(sizeof (uint_t) * 2), bintabcompare); 713 if (bswap) { 714 uint_t *btable = binarytable; 715 uint_t cnt; 716 717 for (cnt = fde_count * 2; cnt-- > 0; btable++) 718 *btable = ld_bswap_Word(*btable); 719 } 720 721 /* 722 * Fill in: 723 * first_frame_ptr 724 * fde_count 725 */ 726 hdroff = 4; 727 /* LINTED */ 728 uint_ptr = (uint_t *)(&hdrdata[hdroff]); 729 *uint_ptr = first_unwind->os_shdr->sh_addr - 730 (hdrosp->os_shdr->sh_addr + hdroff); 731 if (bswap) 732 *uint_ptr = ld_bswap_Word(*uint_ptr); 733 734 hdroff += 4; 735 /* LINTED */ 736 uint_ptr = (uint_t *)&hdrdata[hdroff]; 737 *uint_ptr = fde_count; 738 if (bswap) 739 *uint_ptr = ld_bswap_Word(*uint_ptr); 740 741 /* 742 * If relaxed relocations are active, then there is a chance 743 * that we didn't use all the space reserved for this section. 744 * For details, see the note at head of ld_unwind_make_hdr() above. 745 * 746 * Find the PT_SUNW_UNWIND program header, and change the size values 747 * to the size of the subset of the section that was actually used. 748 */ 749 if (ofl->ofl_flags1 & FLG_OF1_RLXREL) { 750 Word phnum = ofl->ofl_nehdr->e_phnum; 751 Phdr *phdr = ofl->ofl_phdr; 752 753 for (; phnum-- > 0; phdr++) { 754 if (phdr->p_type == PT_SUNW_UNWIND) { 755 phdr->p_memsz = 12 + (8 * fde_count); 756 phdr->p_filesz = phdr->p_memsz; 757 break; 758 } 759 } 760 } 761 762 return (1); 763 } 764 765 /* 766 * Append an .eh_frame section to our output list if not already present. 767 * 768 * Usually, there is a single .eh_frame output section. However, there can 769 * be more if there are incompatible section flags on incoming sections. 770 * If this does happen, the frame_ptr field of the eh_frame_hdr section 771 * will point at the base of the first output section, and the other 772 * sections will not be accessible via frame_ptr. However, the .eh_frame_hdr 773 * will be able to access all the data in the different .eh_frame sections, 774 * because the entries in sorted table are all encoded as DW_EH_PE_datarel. 775 */ 776 uintptr_t 777 ld_unwind_register(Os_desc *osp, Ofl_desc * ofl) 778 { 779 Aliste idx; 780 Os_desc *_osp; 781 /* 782 * Check to see if this output section is already 783 * on the list. 784 */ 785 for (APLIST_TRAVERSE(ofl->ofl_unwind, idx, _osp)) 786 if (osp == _osp) 787 return (1); 788 789 /* 790 * Append output section to unwind list 791 */ 792 if (aplist_append(&ofl->ofl_unwind, osp, AL_CNT_OFL_UNWIND) == NULL) 793 return (S_ERROR); 794 795 return (1); 796 } 797