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) 1988 AT&T 24 * All Rights Reserved 25 * 26 * 27 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 28 * Use is subject to license terms. 29 */ 30 31 #pragma ident "%Z%%M% %I% %E% SMI" 32 33 #if !defined(_ELF64) 34 #pragma weak elf_update = _elf_update 35 #endif 36 37 #include "syn.h" 38 #include <memory.h> 39 #include <malloc.h> 40 #include <limits.h> 41 42 #include <sgs.h> 43 #include "decl.h" 44 #include "msg.h" 45 46 /* 47 * This module is compiled twice, the second time having 48 * -D_ELF64 defined. The following set of macros, along 49 * with machelf.h, represent the differences between the 50 * two compilations. Be careful *not* to add any class- 51 * dependent code (anything that has elf32 or elf64 in the 52 * name) to this code without hiding it behind a switch- 53 * able macro like these. 54 */ 55 #if defined(_ELF64) 56 57 #define FSZ_LONG ELF64_FSZ_XWORD 58 #define ELFCLASS ELFCLASS64 59 #define _elf_snode_init _elf64_snode_init 60 #define _elfxx_cookscn _elf64_cookscn 61 #define _elf_upd_lib _elf64_upd_lib 62 #define elf_fsize elf64_fsize 63 #define _elf_entsz _elf64_entsz 64 #define _elf_msize _elf64_msize 65 #define _elf_upd_usr _elf64_upd_usr 66 #define wrt wrt64 67 #define elf_xlatetof elf64_xlatetof 68 #define _elfxx_update _elf64_update 69 #define _elfxx_swap_wrimage _elf64_swap_wrimage 70 71 #else /* ELF32 */ 72 73 #define FSZ_LONG ELF32_FSZ_WORD 74 #define ELFCLASS ELFCLASS32 75 #define _elf_snode_init _elf32_snode_init 76 #define _elfxx_cookscn _elf32_cookscn 77 #define _elf_upd_lib _elf32_upd_lib 78 #define elf_fsize elf32_fsize 79 #define _elf_entsz _elf32_entsz 80 #define _elf_msize _elf32_msize 81 #define _elf_upd_usr _elf32_upd_usr 82 #define wrt wrt32 83 #define elf_xlatetof elf32_xlatetof 84 #define _elfxx_update _elf32_update 85 #define _elfxx_swap_wrimage _elf32_swap_wrimage 86 87 #endif /* ELF64 */ 88 89 90 #if !(defined(_LP64) && defined(_ELF64)) 91 #define TEST_SIZE 92 93 /* 94 * Handle the decision of whether the current linker can handle the 95 * desired object size, and if not, which error to issue. 96 * 97 * Input is the desired size. On failure, an error has been issued 98 * and 0 is returned. On success, 1 is returned. 99 */ 100 static int 101 test_size(Lword hi) 102 { 103 #ifndef _LP64 /* 32-bit linker */ 104 /* 105 * A 32-bit libelf is limited to a 2GB output file. This limit 106 * is due to the fact that off_t is a signed value, and that 107 * libelf cannot support large file support: 108 * - ABI reasons 109 * - Memory use generally is 2x output file size anyway, 110 * so lifting the file size limit will just send 111 * you crashing into the 32-bit VM limit. 112 * If the output is an ELFCLASS64 object, or an ELFCLASS32 object 113 * under 4GB, switching to the 64-bit version of libelf will help. 114 * However, an ELFCLASS32 object must not exceed 4GB. 115 */ 116 if (hi > INT_MAX) { /* Bigger than 2GB */ 117 #ifndef _ELF64 118 /* ELFCLASS32 object is fundamentally too big? */ 119 if (hi > UINT_MAX) { 120 _elf_seterr(EFMT_FBIG_CLASS32, 0); 121 return (0); 122 } 123 #endif /* _ELF64 */ 124 125 /* Should switch to the 64-bit libelf? */ 126 _elf_seterr(EFMT_FBIG_LARGEFILE, 0); 127 return (0); 128 } 129 #endif /* !_LP64 */ 130 131 132 #if defined(_LP64) && !defined(_ELF64) /* 64-bit linker, ELFCLASS32 */ 133 /* 134 * A 64-bit linker can produce any size output 135 * file, but if the resulting file is ELFCLASS32, 136 * it must not exceed 4GB. 137 */ 138 if (hi > UINT_MAX) { 139 _elf_seterr(EFMT_FBIG_CLASS32, 0); 140 return (0); 141 } 142 #endif 143 144 return (1); 145 } 146 #endif /* TEST_SIZE */ 147 148 /* 149 * Output file update 150 * These functions walk an Elf structure, update its information, 151 * and optionally write the output file. Because the application 152 * may control of the output file layout, two upd_... routines 153 * exist. They're similar but too different to merge cleanly. 154 * 155 * The library defines a "dirty" bit to force parts of the file 156 * to be written on update. These routines ignore the dirty bit 157 * and do everything. A minimal update routine might be useful 158 * someday. 159 */ 160 161 static size_t 162 _elf_upd_lib(Elf * elf) 163 { 164 NOTE(ASSUMING_PROTECTED(*elf)) 165 Lword hi; 166 Lword hibit; 167 Elf_Scn * s; 168 register Lword sz; 169 Ehdr * eh = elf->ed_ehdr; 170 unsigned ver = eh->e_version; 171 register char *p = (char *)eh->e_ident; 172 size_t scncnt; 173 174 /* 175 * Ehdr and Phdr table go first 176 */ 177 p[EI_MAG0] = ELFMAG0; 178 p[EI_MAG1] = ELFMAG1; 179 p[EI_MAG2] = ELFMAG2; 180 p[EI_MAG3] = ELFMAG3; 181 p[EI_CLASS] = ELFCLASS; 182 /* LINTED */ 183 p[EI_VERSION] = (Byte)ver; 184 hi = elf_fsize(ELF_T_EHDR, 1, ver); 185 /* LINTED */ 186 eh->e_ehsize = (Half)hi; 187 if (eh->e_phnum != 0) { 188 /* LINTED */ 189 eh->e_phentsize = (Half)elf_fsize(ELF_T_PHDR, 1, ver); 190 /* LINTED */ 191 eh->e_phoff = (Off)hi; 192 hi += eh->e_phentsize * eh->e_phnum; 193 } else { 194 eh->e_phoff = 0; 195 eh->e_phentsize = 0; 196 } 197 198 /* 199 * Obtain the first section header. Typically, this section has NULL 200 * contents, however in the case of Extended ELF Sections this section 201 * is used to hold an alternative e_shnum, e_shstrndx and e_phnum. 202 * On initial allocation (see _elf_snode) the elements of this section 203 * would have been zeroed. The e_shnum is initialized later, after the 204 * section header count has been determined. The e_shstrndx and 205 * e_phnum may have already been initialized by the caller (for example, 206 * gelf_update_shdr() in mcs(1)). 207 */ 208 if ((s = elf->ed_hdscn) == 0) { 209 eh->e_shnum = 0; 210 scncnt = 0; 211 } else { 212 s = s->s_next; 213 scncnt = 1; 214 } 215 216 /* 217 * Loop through sections. Compute section size before changing hi. 218 * Allow null buffers for NOBITS. 219 */ 220 hibit = 0; 221 for (; s != 0; s = s->s_next) { 222 register Dnode *d; 223 register Lword fsz, j; 224 Shdr *sh = s->s_shdr; 225 226 scncnt++; 227 if (sh->sh_type == SHT_NULL) { 228 *sh = _elf_snode_init.sb_shdr; 229 continue; 230 } 231 232 if ((s->s_myflags & SF_READY) == 0) 233 (void) _elfxx_cookscn(s); 234 235 sh->sh_addralign = 1; 236 if ((sz = (Lword)_elf_entsz(elf, sh->sh_type, ver)) != 0) 237 /* LINTED */ 238 sh->sh_entsize = (Half)sz; 239 sz = 0; 240 for (d = s->s_hdnode; d != 0; d = d->db_next) { 241 if ((fsz = elf_fsize(d->db_data.d_type, 242 1, ver)) == 0) 243 return (0); 244 245 j = _elf_msize(d->db_data.d_type, ver); 246 fsz *= (d->db_data.d_size / j); 247 d->db_osz = (size_t)fsz; 248 if ((j = d->db_data.d_align) > 1) { 249 if (j > sh->sh_addralign) 250 sh->sh_addralign = (Xword)j; 251 252 if (sz % j != 0) 253 sz += j - sz % j; 254 } 255 d->db_data.d_off = (off_t)sz; 256 d->db_xoff = sz; 257 sz += fsz; 258 } 259 260 sh->sh_size = (Xword) sz; 261 /* 262 * We want to take into account the offsets for NOBITS 263 * sections and let the "sh_offsets" point to where 264 * the section would 'conceptually' fit within 265 * the file (as required by the ABI). 266 * 267 * But - we must also make sure that the NOBITS does 268 * not take up any actual space in the file. We preserve 269 * the actual offset into the file in the 'hibit' variable. 270 * When we come to the first non-NOBITS section after a 271 * encountering a NOBITS section the hi counter is restored 272 * to its proper place in the file. 273 */ 274 if (sh->sh_type == SHT_NOBITS) { 275 if (hibit == 0) 276 hibit = hi; 277 } else { 278 if (hibit) { 279 hi = hibit; 280 hibit = 0; 281 } 282 } 283 j = sh->sh_addralign; 284 if ((fsz = hi % j) != 0) 285 hi += j - fsz; 286 287 /* LINTED */ 288 sh->sh_offset = (Off)hi; 289 hi += sz; 290 } 291 292 /* 293 * if last section was a 'NOBITS' section then we need to 294 * restore the 'hi' counter to point to the end of the last 295 * non 'NOBITS' section. 296 */ 297 if (hibit) { 298 hi = hibit; 299 hibit = 0; 300 } 301 302 /* 303 * Shdr table last 304 */ 305 if (scncnt != 0) { 306 if (hi % FSZ_LONG != 0) 307 hi += FSZ_LONG - hi % FSZ_LONG; 308 /* LINTED */ 309 eh->e_shoff = (Off)hi; 310 /* 311 * If we are using 'extended sections' then the 312 * e_shnum is stored in the sh_size field of the 313 * first section header. 314 * 315 * NOTE: we set e_shnum to '0' because it's specified 316 * this way in the gABI, and in the hopes that 317 * this will cause less problems to unaware 318 * tools then if we'd set it to SHN_XINDEX (0xffff). 319 */ 320 if (scncnt < SHN_LORESERVE) 321 eh->e_shnum = scncnt; 322 else { 323 Shdr *sh; 324 sh = (Shdr *)elf->ed_hdscn->s_shdr; 325 sh->sh_size = scncnt; 326 eh->e_shnum = 0; 327 } 328 /* LINTED */ 329 eh->e_shentsize = (Half)elf_fsize(ELF_T_SHDR, 1, ver); 330 hi += eh->e_shentsize * scncnt; 331 } else { 332 eh->e_shoff = 0; 333 eh->e_shentsize = 0; 334 } 335 336 #ifdef TEST_SIZE 337 if (test_size(hi) == 0) 338 return (0); 339 #endif 340 341 return ((size_t)hi); 342 } 343 344 345 346 static size_t 347 _elf_upd_usr(Elf * elf) 348 { 349 NOTE(ASSUMING_PROTECTED(*elf)) 350 Lword hi; 351 Elf_Scn * s; 352 register Lword sz; 353 Ehdr * eh = elf->ed_ehdr; 354 unsigned ver = eh->e_version; 355 register char *p = (char *)eh->e_ident; 356 357 358 /* 359 * Ehdr and Phdr table go first 360 */ 361 p[EI_MAG0] = ELFMAG0; 362 p[EI_MAG1] = ELFMAG1; 363 p[EI_MAG2] = ELFMAG2; 364 p[EI_MAG3] = ELFMAG3; 365 p[EI_CLASS] = ELFCLASS; 366 /* LINTED */ 367 p[EI_VERSION] = (Byte)ver; 368 hi = elf_fsize(ELF_T_EHDR, 1, ver); 369 /* LINTED */ 370 eh->e_ehsize = (Half)hi; 371 372 /* 373 * If phnum is zero, phoff "should" be zero too, 374 * but the application is responsible for it. 375 * Allow a non-zero value here and update the 376 * hi water mark accordingly. 377 */ 378 379 if (eh->e_phnum != 0) 380 /* LINTED */ 381 eh->e_phentsize = (Half)elf_fsize(ELF_T_PHDR, 1, ver); 382 else 383 eh->e_phentsize = 0; 384 if ((sz = eh->e_phoff + eh->e_phentsize * eh->e_phnum) > hi) 385 hi = sz; 386 387 /* 388 * Loop through sections, skipping index zero. 389 * Compute section size before changing hi. 390 * Allow null buffers for NOBITS. 391 */ 392 393 if ((s = elf->ed_hdscn) == 0) 394 eh->e_shnum = 0; 395 else { 396 eh->e_shnum = 1; 397 *(Shdr*)s->s_shdr = _elf_snode_init.sb_shdr; 398 s = s->s_next; 399 } 400 for (; s != 0; s = s->s_next) { 401 register Dnode *d; 402 register Lword fsz, j; 403 Shdr *sh = s->s_shdr; 404 405 if ((s->s_myflags & SF_READY) == 0) 406 (void) _elfxx_cookscn(s); 407 408 ++eh->e_shnum; 409 sz = 0; 410 for (d = s->s_hdnode; d != 0; d = d->db_next) { 411 if ((fsz = elf_fsize(d->db_data.d_type, 1, 412 ver)) == 0) 413 return (0); 414 j = _elf_msize(d->db_data.d_type, ver); 415 fsz *= (d->db_data.d_size / j); 416 d->db_osz = (size_t)fsz; 417 418 if ((sh->sh_type != SHT_NOBITS) && 419 ((j = (d->db_data.d_off + d->db_osz)) > sz)) 420 sz = j; 421 } 422 if (sh->sh_size < sz) { 423 _elf_seterr(EFMT_SCNSZ, 0); 424 return (0); 425 } 426 if ((sh->sh_type != SHT_NOBITS) && 427 (hi < sh->sh_offset + sh->sh_size)) 428 hi = sh->sh_offset + sh->sh_size; 429 } 430 431 /* 432 * Shdr table last. Comment above for phnum/phoff applies here. 433 */ 434 if (eh->e_shnum != 0) 435 /* LINTED */ 436 eh->e_shentsize = (Half)elf_fsize(ELF_T_SHDR, 1, ver); 437 else 438 eh->e_shentsize = 0; 439 440 if ((sz = eh->e_shoff + eh->e_shentsize * eh->e_shnum) > hi) 441 hi = sz; 442 443 #ifdef TEST_SIZE 444 if (test_size(hi) == 0) 445 return (0); 446 #endif 447 448 return ((size_t)hi); 449 } 450 451 452 static size_t 453 wrt(Elf * elf, Xword outsz, unsigned fill, int update_cmd) 454 { 455 NOTE(ASSUMING_PROTECTED(*elf)) 456 Elf_Data dst, src; 457 unsigned flag; 458 Xword hi, sz; 459 char *image; 460 Elf_Scn *s; 461 Ehdr *eh = elf->ed_ehdr; 462 unsigned ver = eh->e_version; 463 unsigned encode; 464 int byte; 465 466 /* 467 * If this is an ELF_C_WRIMAGE write, then we encode into the 468 * byte order of the system we are running on rather than that of 469 * of the object. For ld.so.1, this is the same order, but 470 * for 'ld', it might not be in the case where we are cross 471 * linking an object for a different target. In this later case, 472 * the linker-host byte order is necessary so that the linker can 473 * manipulate the resulting image. It is expected that the linker 474 * will call elf_swap_wrimage() if necessary to convert the image 475 * to the target byte order. 476 */ 477 encode = (update_cmd == ELF_C_WRIMAGE) ? _elf_sys_encoding() : 478 eh->e_ident[EI_DATA]; 479 480 /* 481 * Two issues can cause trouble for the output file. 482 * First, begin() with ELF_C_RDWR opens a file for both 483 * read and write. On the write update(), the library 484 * has to read everything it needs before truncating 485 * the file. Second, using mmap for both read and write 486 * is too tricky. Consequently, the library disables mmap 487 * on the read side. Using mmap for the output saves swap 488 * space, because that mapping is SHARED, not PRIVATE. 489 * 490 * If the file is write-only, there can be nothing of 491 * interest to bother with. 492 * 493 * The following reads the entire file, which might be 494 * more than necessary. Better safe than sorry. 495 */ 496 497 if ((elf->ed_myflags & EDF_READ) && 498 (_elf_vm(elf, (size_t)0, elf->ed_fsz) != OK_YES)) 499 return (0); 500 501 flag = elf->ed_myflags & EDF_WRALLOC; 502 if ((image = _elf_outmap(elf->ed_fd, outsz, &flag)) == 0) 503 return (0); 504 505 if (flag == 0) 506 elf->ed_myflags |= EDF_IMALLOC; 507 508 /* 509 * If an error occurs below, a "dirty" bit may be cleared 510 * improperly. To save a second pass through the file, 511 * this code sets the dirty bit on the elf descriptor 512 * when an error happens, assuming that will "cover" any 513 * accidents. 514 */ 515 516 /* 517 * Hi is needed only when 'fill' is non-zero. 518 * Fill is non-zero only when the library 519 * calculates file/section/data buffer offsets. 520 * The lib guarantees they increase monotonically. 521 * That guarantees proper filling below. 522 */ 523 524 525 /* 526 * Ehdr first 527 */ 528 529 src.d_buf = (Elf_Void *)eh; 530 src.d_type = ELF_T_EHDR; 531 src.d_size = sizeof (Ehdr); 532 src.d_version = EV_CURRENT; 533 dst.d_buf = (Elf_Void *)image; 534 dst.d_size = eh->e_ehsize; 535 dst.d_version = ver; 536 if (elf_xlatetof(&dst, &src, encode) == 0) 537 return (0); 538 elf->ed_ehflags &= ~ELF_F_DIRTY; 539 hi = eh->e_ehsize; 540 541 /* 542 * Phdr table if one exists 543 */ 544 545 if (eh->e_phnum != 0) { 546 unsigned work; 547 /* 548 * Unlike other library data, phdr table is 549 * in the user version. Change src buffer 550 * version here, fix it after translation. 551 */ 552 553 src.d_buf = (Elf_Void *)elf->ed_phdr; 554 src.d_type = ELF_T_PHDR; 555 src.d_size = elf->ed_phdrsz; 556 ELFACCESSDATA(work, _elf_work) 557 src.d_version = work; 558 dst.d_buf = (Elf_Void *)(image + eh->e_phoff); 559 dst.d_size = eh->e_phnum * eh->e_phentsize; 560 hi = (Xword)(eh->e_phoff + dst.d_size); 561 if (elf_xlatetof(&dst, &src, encode) == 0) { 562 elf->ed_uflags |= ELF_F_DIRTY; 563 return (0); 564 } 565 elf->ed_phflags &= ~ELF_F_DIRTY; 566 src.d_version = EV_CURRENT; 567 } 568 569 /* 570 * Loop through sections 571 */ 572 573 ELFACCESSDATA(byte, _elf_byte); 574 for (s = elf->ed_hdscn; s != 0; s = s->s_next) { 575 register Dnode *d, *prevd; 576 Xword off = 0; 577 Shdr *sh = s->s_shdr; 578 char *start = image + sh->sh_offset; 579 char *here; 580 581 /* 582 * Just "clean" DIRTY flag for "empty" sections. Even if 583 * NOBITS needs padding, the next thing in the 584 * file will provide it. (And if this NOBITS is 585 * the last thing in the file, no padding needed.) 586 */ 587 if ((sh->sh_type == SHT_NOBITS) || 588 (sh->sh_type == SHT_NULL)) { 589 d = s->s_hdnode, prevd = 0; 590 for (; d != 0; prevd = d, d = d->db_next) 591 d->db_uflags &= ~ELF_F_DIRTY; 592 continue; 593 } 594 /* 595 * Clear out the memory between the end of the last 596 * section and the begining of this section. 597 */ 598 if (fill && (sh->sh_offset > hi)) { 599 sz = sh->sh_offset - hi; 600 (void) memset(start - sz, byte, sz); 601 } 602 603 604 for (d = s->s_hdnode, prevd = 0; 605 d != 0; prevd = d, d = d->db_next) { 606 d->db_uflags &= ~ELF_F_DIRTY; 607 here = start + d->db_data.d_off; 608 609 /* 610 * Clear out the memory between the end of the 611 * last update and the start of this data buffer. 612 */ 613 if (fill && (d->db_data.d_off > off)) { 614 sz = (Xword)(d->db_data.d_off - off); 615 (void) memset(here - sz, byte, sz); 616 } 617 618 if ((d->db_myflags & DBF_READY) == 0) { 619 SCNLOCK(s); 620 if (_elf_locked_getdata(s, &prevd->db_data) != 621 &d->db_data) { 622 elf->ed_uflags |= ELF_F_DIRTY; 623 SCNUNLOCK(s); 624 return (0); 625 } 626 SCNUNLOCK(s); 627 } 628 dst.d_buf = (Elf_Void *)here; 629 dst.d_size = d->db_osz; 630 631 /* 632 * Copy the translated bits out to the destination 633 * image. 634 */ 635 if (elf_xlatetof(&dst, &d->db_data, encode) == 0) { 636 elf->ed_uflags |= ELF_F_DIRTY; 637 return (0); 638 } 639 640 off = (Xword)(d->db_data.d_off + dst.d_size); 641 } 642 hi = sh->sh_offset + sh->sh_size; 643 } 644 645 /* 646 * Shdr table last 647 */ 648 649 if (fill && (eh->e_shoff > hi)) { 650 sz = eh->e_shoff - hi; 651 (void) memset(image + hi, byte, sz); 652 } 653 654 src.d_type = ELF_T_SHDR; 655 src.d_size = sizeof (Shdr); 656 dst.d_buf = (Elf_Void *)(image + eh->e_shoff); 657 dst.d_size = eh->e_shentsize; 658 for (s = elf->ed_hdscn; s != 0; s = s->s_next) { 659 assert((uintptr_t)dst.d_buf < ((uintptr_t)image + outsz)); 660 s->s_shflags &= ~ELF_F_DIRTY; 661 s->s_uflags &= ~ELF_F_DIRTY; 662 src.d_buf = s->s_shdr; 663 664 if (elf_xlatetof(&dst, &src, encode) == 0) { 665 elf->ed_uflags |= ELF_F_DIRTY; 666 return (0); 667 } 668 669 dst.d_buf = (char *)dst.d_buf + eh->e_shentsize; 670 } 671 /* 672 * ELF_C_WRIMAGE signifyes that we build the memory image, but 673 * that we do not actually write it to disk. This is used 674 * by ld(1) to build up a full image of an elf file and then 675 * to process the file before it's actually written out to 676 * disk. This saves ld(1) the overhead of having to write 677 * the image out to disk twice. 678 */ 679 if (update_cmd == ELF_C_WRIMAGE) { 680 elf->ed_uflags &= ~ELF_F_DIRTY; 681 elf->ed_wrimage = image; 682 elf->ed_wrimagesz = outsz; 683 return (outsz); 684 } 685 686 if (_elf_outsync(elf->ed_fd, image, outsz, 687 ((elf->ed_myflags & EDF_IMALLOC) ? 0 : 1)) != 0) { 688 elf->ed_uflags &= ~ELF_F_DIRTY; 689 elf->ed_myflags &= ~EDF_IMALLOC; 690 return (outsz); 691 } 692 693 elf->ed_uflags |= ELF_F_DIRTY; 694 return (0); 695 } 696 697 698 699 700 /* 701 * The following is a private interface between the linkers (ld & ld.so.1) 702 * and libelf: 703 * 704 * elf_update(elf, ELF_C_WRIMAGE) 705 * This will cause full image representing the elf file 706 * described by the elf pointer to be built in memory. If the 707 * elf pointer has a valid file descriptor associated with it 708 * we will attempt to build the memory image from mmap()'ed 709 * storage. If the elf descriptor does not have a valid 710 * file descriptor (opened with elf_begin(0, ELF_C_IMAGE, 0)) 711 * then the image will be allocated from dynamic memory (malloc()). 712 * 713 * elf_update() will return the size of the memory image built 714 * when sucessful. 715 * 716 * When a subsequent call to elf_update() with ELF_C_WRITE as 717 * the command is performed it will sync the image created 718 * by ELF_C_WRIMAGE to disk (if fd available) and 719 * free the memory allocated. 720 */ 721 722 off_t 723 _elfxx_update(Elf * elf, Elf_Cmd cmd) 724 { 725 size_t sz; 726 unsigned u; 727 Ehdr *eh = elf->ed_ehdr; 728 729 if (elf == 0) 730 return (-1); 731 732 ELFWLOCK(elf) 733 switch (cmd) { 734 default: 735 _elf_seterr(EREQ_UPDATE, 0); 736 ELFUNLOCK(elf) 737 return (-1); 738 739 case ELF_C_WRIMAGE: 740 if ((elf->ed_myflags & EDF_WRITE) == 0) { 741 _elf_seterr(EREQ_UPDWRT, 0); 742 ELFUNLOCK(elf) 743 return (-1); 744 } 745 break; 746 case ELF_C_WRITE: 747 if ((elf->ed_myflags & EDF_WRITE) == 0) { 748 _elf_seterr(EREQ_UPDWRT, 0); 749 ELFUNLOCK(elf) 750 return (-1); 751 } 752 if (elf->ed_wrimage) { 753 if (elf->ed_myflags & EDF_WRALLOC) { 754 free(elf->ed_wrimage); 755 /* 756 * The size is still returned even 757 * though nothing is actually written 758 * out. This is just to be consistant 759 * with the rest of the interface. 760 */ 761 sz = elf->ed_wrimagesz; 762 elf->ed_wrimage = 0; 763 elf->ed_wrimagesz = 0; 764 ELFUNLOCK(elf); 765 return ((off_t)sz); 766 } 767 sz = _elf_outsync(elf->ed_fd, elf->ed_wrimage, 768 elf->ed_wrimagesz, 769 (elf->ed_myflags & EDF_IMALLOC ? 0 : 1)); 770 elf->ed_myflags &= ~EDF_IMALLOC; 771 elf->ed_wrimage = 0; 772 elf->ed_wrimagesz = 0; 773 ELFUNLOCK(elf); 774 return ((off_t)sz); 775 } 776 /* FALLTHROUGH */ 777 case ELF_C_NULL: 778 break; 779 } 780 781 if (eh == 0) { 782 _elf_seterr(ESEQ_EHDR, 0); 783 ELFUNLOCK(elf) 784 return (-1); 785 } 786 787 if ((u = eh->e_version) > EV_CURRENT) { 788 _elf_seterr(EREQ_VER, 0); 789 ELFUNLOCK(elf) 790 return (-1); 791 } 792 793 if (u == EV_NONE) 794 eh->e_version = EV_CURRENT; 795 796 if ((u = eh->e_ident[EI_DATA]) == ELFDATANONE) { 797 unsigned encode; 798 799 ELFACCESSDATA(encode, _elf_encode) 800 if (encode == ELFDATANONE) { 801 _elf_seterr(EREQ_ENCODE, 0); 802 ELFUNLOCK(elf) 803 return (-1); 804 } 805 /* LINTED */ 806 eh->e_ident[EI_DATA] = (Byte)encode; 807 } 808 809 u = 1; 810 if (elf->ed_uflags & ELF_F_LAYOUT) { 811 sz = _elf_upd_usr(elf); 812 u = 0; 813 } else 814 sz = _elf_upd_lib(elf); 815 816 if ((sz != 0) && ((cmd == ELF_C_WRITE) || (cmd == ELF_C_WRIMAGE))) 817 sz = wrt(elf, (Xword)sz, u, cmd); 818 819 if (sz == 0) { 820 ELFUNLOCK(elf) 821 return (-1); 822 } 823 824 ELFUNLOCK(elf) 825 return ((off_t)sz); 826 } 827 828 829 /* 830 * When wrt() processes an ELF_C_WRIMAGE request, the resulting image 831 * gets the byte order (encoding) of the platform running the linker 832 * rather than that of the target host. This allows the linker to modify 833 * the image, prior to flushing it to the output file. This routine 834 * is used to re-translate such an image into the byte order of the 835 * target host. 836 */ 837 int 838 _elfxx_swap_wrimage(Elf * elf) 839 { 840 NOTE(ASSUMING_PROTECTED(*elf)) 841 Elf_Data dst, src; 842 Elf_Scn *s; 843 Ehdr *eh = elf->ed_ehdr; 844 Half e_phnum = eh->e_phnum; 845 unsigned ver = eh->e_version; 846 unsigned encode = eh->e_ident[EI_DATA]; 847 848 /* 849 * Ehdr first 850 */ 851 852 src.d_buf = dst.d_buf = (Elf_Void *)eh; 853 src.d_type = dst.d_type = ELF_T_EHDR; 854 src.d_size = dst.d_size = sizeof (Ehdr); 855 src.d_version = dst.d_version = ver; 856 if (elf_xlatetof(&dst, &src, encode) == 0) 857 return (1); 858 859 /* 860 * Phdr table if one exists 861 */ 862 863 if (e_phnum != 0) { 864 unsigned work; 865 /* 866 * Unlike other library data, phdr table is 867 * in the user version. 868 */ 869 870 src.d_buf = dst.d_buf = (Elf_Void *)elf->ed_phdr; 871 src.d_type = dst.d_type = ELF_T_PHDR; 872 src.d_size = dst.d_size = elf->ed_phdrsz; 873 ELFACCESSDATA(work, _elf_work) 874 src.d_version = dst.d_version = work; 875 if (elf_xlatetof(&dst, &src, encode) == 0) { 876 return (1); 877 } 878 } 879 880 /* 881 * Loop through sections 882 */ 883 884 for (s = elf->ed_hdscn; s != 0; s = s->s_next) { 885 register Dnode *d, *prevd; 886 Shdr *sh = s->s_shdr; 887 888 if ((sh->sh_type == SHT_NOBITS) || (sh->sh_type == SHT_NULL)) 889 continue; 890 891 for (d = s->s_hdnode, prevd = 0; 892 d != 0; prevd = d, d = d->db_next) { 893 894 if ((d->db_myflags & DBF_READY) == 0) { 895 SCNLOCK(s); 896 if (_elf_locked_getdata(s, &prevd->db_data) != 897 &d->db_data) { 898 SCNUNLOCK(s); 899 return (1); 900 } 901 SCNUNLOCK(s); 902 } 903 904 dst = d->db_data; 905 if (elf_xlatetof(&dst, &d->db_data, encode) == 0) 906 return (1); 907 } 908 } 909 910 /* 911 * Shdr table 912 */ 913 914 src.d_type = dst.d_type = ELF_T_SHDR; 915 src.d_version = dst.d_version = ver; 916 for (s = elf->ed_hdscn; s != 0; s = s->s_next) { 917 src.d_buf = dst.d_buf = s->s_shdr; 918 src.d_size = dst.d_size = sizeof (Shdr); 919 if (elf_xlatetof(&dst, &src, encode) == 0) 920 return (1); 921 } 922 923 return (0); 924 } 925 926 927 928 #ifndef _ELF64 929 /* class-independent, only needs to be compiled once */ 930 931 off_t 932 elf_update(Elf *elf, Elf_Cmd cmd) 933 { 934 if (elf == 0) 935 return (-1); 936 937 if (elf->ed_class == ELFCLASS32) 938 return (_elf32_update(elf, cmd)); 939 else if (elf->ed_class == ELFCLASS64) { 940 return (_elf64_update(elf, cmd)); 941 } 942 943 _elf_seterr(EREQ_CLASS, 0); 944 return (-1); 945 } 946 947 int 948 _elf_swap_wrimage(Elf *elf) 949 { 950 if (elf == 0) 951 return (0); 952 953 if (elf->ed_class == ELFCLASS32) 954 return (_elf32_swap_wrimage(elf)); 955 956 if (elf->ed_class == ELFCLASS64) 957 return (_elf64_swap_wrimage(elf)); 958 959 _elf_seterr(EREQ_CLASS, 0); 960 return (0); 961 } 962 963 /* 964 * 4106312, 4106398, This is an ad-hoc means for the 32-bit 965 * Elf64 version of libld.so.3 to get around the limitation 966 * of a 32-bit d_off field. This is only intended to be 967 * used by libld to relocate symbols in large NOBITS sections. 968 */ 969 Elf64_Off 970 _elf_getxoff(Elf_Data * d) 971 { 972 return (((Dnode *)d)->db_xoff); 973 } 974 #endif /* !_ELF64 */ 975