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 * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved. 27 * 28 * Copyright 2020 Joyent, Inc. 29 */ 30 31 /* 32 * Processing of relocatable objects and shared objects. 33 */ 34 35 /* 36 * ld -- link/editor main program 37 */ 38 #include <sys/types.h> 39 #include <sys/time.h> 40 #include <sys/mman.h> 41 #include <string.h> 42 #include <stdio.h> 43 #include <locale.h> 44 #include <stdarg.h> 45 #include <debug.h> 46 #include "msg.h" 47 #include "_libld.h" 48 49 /* 50 * All target specific code is referenced via this global variable, which 51 * is initialized in ld_main(). This allows the linker to function as 52 * a cross linker, by vectoring to the target-specific code for the 53 * current target machine. 54 */ 55 Target ld_targ; 56 57 /* 58 * A default library search path is used if one was not supplied on the command 59 * line. Note: these strings can not use MSG_ORIG() since they are modified as 60 * part of the path processing. 61 */ 62 #if defined(_ELF64) 63 static char def_Plibpath[] = "/lib/64:/usr/lib/64"; 64 #else 65 static char def_Plibpath[] = "/usr/ccs/lib:/lib:/usr/lib"; 66 #endif 67 68 /* 69 * A default elf header provides for simplifying diagnostic processing. 70 */ 71 static Ehdr def_ehdr = { { ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3, 72 ELFCLASSNONE, ELFDATANONE }, 0, EM_NONE, 73 EV_CURRENT }; 74 75 /* 76 * ld-centric wrapper on top of veprintf(): 77 * - Accepts output descriptor rather than linkmap list 78 * - Sets the FLG_OF_FATAL/FLG_OF_WARN flags as necessary 79 */ 80 void 81 ld_eprintf(Ofl_desc *ofl, Error error, const char *format, ...) 82 { 83 va_list args; 84 85 /* Set flag indicating type of error being issued */ 86 switch (error) { 87 case ERR_NONE: 88 case ERR_WARNING_NF: 89 break; 90 case ERR_WARNING: 91 ofl->ofl_flags |= FLG_OF_WARN; 92 break; 93 case ERR_GUIDANCE: 94 ofl->ofl_guideflags |= FLG_OFG_ISSUED; 95 ofl->ofl_flags |= FLG_OF_WARN; 96 break; 97 default: 98 ofl->ofl_flags |= FLG_OF_FATAL; 99 } 100 101 /* Issue the error */ 102 va_start(args, format); 103 veprintf(ofl->ofl_lml, error, format, args); 104 va_end(args); 105 } 106 107 /* 108 * Establish the global state necessary to link the desired machine 109 * target, as reflected by the ld_targ global variable. 110 */ 111 int 112 ld_init_target(Lm_list *lml, Half mach) 113 { 114 switch (mach) { 115 case EM_386: 116 case EM_AMD64: 117 ld_targ = *ld_targ_init_x86(); 118 break; 119 120 case EM_SPARC: 121 case EM_SPARC32PLUS: 122 case EM_SPARCV9: 123 ld_targ = *ld_targ_init_sparc(); 124 break; 125 126 default: 127 { 128 Conv_inv_buf_t inv_buf; 129 130 eprintf(lml, ERR_FATAL, MSG_INTL(MSG_TARG_UNSUPPORTED), 131 conv_ehdr_mach(mach, 0, &inv_buf)); 132 return (1); 133 } 134 } 135 136 return (0); 137 } 138 139 140 /* 141 * The main program 142 */ 143 int 144 ld_main(int argc, char **argv, Half mach) 145 { 146 char *sgs_support; /* SGS_SUPPORT environment string */ 147 Half etype; 148 Ofl_desc *ofl; 149 ofl_flag_t save_flg_of_warn; 150 151 /* 152 * Establish a base time. Total time diagnostics are relative to 153 * entering the link-editor here. 154 */ 155 (void) gettimeofday(&DBG_TOTALTIME, NULL); 156 DBG_DELTATIME = DBG_TOTALTIME; 157 158 /* Output file descriptor */ 159 if ((ofl = libld_calloc(1, sizeof (Ofl_desc))) == NULL) 160 return (1); 161 162 /* Initialize target state */ 163 if (ld_init_target(NULL, mach) != 0) 164 return (1); 165 166 /* 167 * Set up the default output ELF header to satisfy diagnostic 168 * requirements, and initialize the machine and class details. 169 */ 170 ofl->ofl_dehdr = &def_ehdr; 171 def_ehdr.e_ident[EI_CLASS] = ld_targ.t_m.m_class; 172 def_ehdr.e_ident[EI_DATA] = ld_targ.t_m.m_data; 173 def_ehdr.e_machine = ld_targ.t_m.m_mach; 174 175 /* 176 * Build up linker version string 177 */ 178 if ((ofl->ofl_sgsid = libld_calloc(MSG_SGS_ID_SIZE + 179 strlen(link_ver_string) + 1, 1)) == NULL) 180 return (1); 181 (void) strcpy(ofl->ofl_sgsid, MSG_ORIG(MSG_SGS_ID)); 182 (void) strcat(ofl->ofl_sgsid, link_ver_string); 183 184 /* 185 * Argument pass one. Get all the input flags (skip any files) and 186 * check for consistency. Return from ld_process_flags() marks the 187 * end of mapfile processing. The entrance criteria and segment 188 * descriptors are complete and in their final form. 189 */ 190 if (ld_process_flags(ofl, argc, argv) == S_ERROR) { 191 /* If any ERR_GUIDANCE messages were issued, add a summary */ 192 if (ofl->ofl_guideflags & FLG_OFG_ISSUED) 193 ld_eprintf(ofl, ERR_GUIDANCE, 194 MSG_INTL(MSG_GUIDE_SUMMARY)); 195 return (1); 196 } 197 198 if (ofl->ofl_flags & FLG_OF_FATAL) { 199 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ARG_FLAGS)); 200 /* If any ERR_GUIDANCE messages were issued, add a summary */ 201 if (ofl->ofl_guideflags & FLG_OFG_ISSUED) 202 ld_eprintf(ofl, ERR_GUIDANCE, 203 MSG_INTL(MSG_GUIDE_SUMMARY)); 204 return (1); 205 } 206 207 /* 208 * At this point a call such as ld -V is considered complete. 209 */ 210 if (ofl->ofl_flags1 & FLG_OF1_DONE) 211 return (0); 212 213 /* Initialize signal handler */ 214 ld_init_sighandler(ofl); 215 216 /* 217 * Determine whether any support libraries should be loaded, 218 * (either through the SGS_SUPPORT environment variable and/or 219 * through the -S option). 220 */ 221 #if defined(_LP64) 222 if ((sgs_support = getenv(MSG_ORIG(MSG_SGS_SUPPORT_64))) == NULL) 223 #else 224 if ((sgs_support = getenv(MSG_ORIG(MSG_SGS_SUPPORT_32))) == NULL) 225 #endif 226 sgs_support = getenv(MSG_ORIG(MSG_SGS_SUPPORT)); 227 228 if (sgs_support && sgs_support[0]) { 229 const char *sep = MSG_ORIG(MSG_STR_COLON); 230 char *lib; 231 char *lasts; 232 233 DBG_CALL(Dbg_support_req(ofl->ofl_lml, sgs_support, 234 DBG_SUP_ENVIRON)); 235 if ((lib = strtok_r(sgs_support, sep, &lasts)) != NULL) { 236 do { 237 if (ld_sup_loadso(ofl, lib) == S_ERROR) 238 return (ld_exit(ofl)); 239 DBG_CALL(Dbg_util_nl(ofl->ofl_lml, DBG_NL_STD)); 240 241 } while ((lib = strtok_r(NULL, sep, &lasts)) != NULL); 242 } 243 } 244 if (lib_support) { 245 Aliste idx; 246 char *lib; 247 248 for (APLIST_TRAVERSE(lib_support, idx, lib)) { 249 DBG_CALL(Dbg_support_req(ofl->ofl_lml, lib, 250 DBG_SUP_CMDLINE)); 251 if (ld_sup_loadso(ofl, lib) == S_ERROR) 252 return (ld_exit(ofl)); 253 DBG_CALL(Dbg_util_nl(ofl->ofl_lml, DBG_NL_STD)); 254 } 255 } 256 257 DBG_CALL(Dbg_ent_print(ofl->ofl_lml, 258 ofl->ofl_dehdr->e_ident[EI_OSABI], ofl->ofl_dehdr->e_machine, 259 ofl->ofl_ents)); 260 DBG_CALL(Dbg_seg_list(ofl->ofl_lml, 261 ofl->ofl_dehdr->e_ident[EI_OSABI], ofl->ofl_dehdr->e_machine, 262 ofl->ofl_segs)); 263 264 /* 265 * The objscnt and soscnt variables were used to estimate the expected 266 * input files, and size the symbol hash buckets accordingly. Reset 267 * these values now, so as to gain an accurate count from pass two, for 268 * later statistics diagnostics. 269 */ 270 ofl->ofl_objscnt = ofl->ofl_soscnt = 0; 271 272 /* 273 * Determine whether we can create the file before going any further. 274 */ 275 if (ld_open_outfile(ofl) == S_ERROR) 276 return (ld_exit(ofl)); 277 278 /* 279 * If the user didn't supply a library path supply a default. And, if 280 * no run-path has been specified (-R), see if the environment variable 281 * is in use (historic). 282 */ 283 if (Plibpath == NULL) 284 Plibpath = def_Plibpath; 285 286 if (ofl->ofl_rpath == NULL) { 287 char *rpath; 288 289 if (((rpath = getenv(MSG_ORIG(MSG_LD_RUN_PATH))) != NULL) && 290 rpath[0]) 291 ofl->ofl_rpath = rpath; 292 } 293 294 /* 295 * Argument pass two. Input all libraries and objects. 296 */ 297 if (ld_lib_setup(ofl) == S_ERROR) 298 return (ld_exit(ofl)); 299 300 /* 301 * Call ld_start() with the etype of our output file and the 302 * output file name. 303 */ 304 if (ofl->ofl_flags & FLG_OF_SHAROBJ) 305 etype = ET_DYN; 306 else if (ofl->ofl_flags & FLG_OF_RELOBJ) 307 etype = ET_REL; 308 else 309 etype = ET_EXEC; 310 311 ld_sup_start(ofl, etype, argv[0]); 312 313 /* 314 * Process all input files. 315 */ 316 if (ld_process_files(ofl, argc, argv) == S_ERROR) 317 return (ld_exit(ofl)); 318 if (ofl->ofl_flags & FLG_OF_FATAL) { 319 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ARG_FILES), 320 ofl->ofl_name); 321 return (ld_exit(ofl)); 322 } 323 324 ld_sup_input_done(ofl); 325 326 /* 327 * Now that all input section processing is complete, validate and 328 * process any SHT_SUNW_move sections. 329 */ 330 if (ofl->ofl_ismove && (ld_process_move(ofl) == S_ERROR)) 331 return (ld_exit(ofl)); 332 333 /* 334 * Before validating all symbols count the number of relocation entries. 335 * If copy relocations exist, COMMON symbols must be generated which are 336 * assigned to the executables .bss. During sym_validate() the actual 337 * size and alignment of the .bss is calculated. Doing things in this 338 * order reduces the number of symbol table traversals required (however 339 * it does take a little longer for the user to be told of any undefined 340 * symbol errors). 341 */ 342 if (ld_reloc_init(ofl) == S_ERROR) 343 return (ld_exit(ofl)); 344 345 /* 346 * We need to know if FLG_OF_WARN is currently set, in case 347 * we need to honor a -z fatal-warnings request. However, we also 348 * need to know if a warning due to symbol validation results from 349 * the upcoming call to ld_sym_validate() in order to issue the 350 * appropriate message for it. So we save the current value, 351 * and clear the main flag. 352 */ 353 save_flg_of_warn = ofl->ofl_flags & FLG_OF_WARN; 354 ofl->ofl_flags &= ~FLG_OF_WARN; 355 356 if (ld_sym_validate(ofl) == S_ERROR) 357 return (ld_exit(ofl)); 358 359 /* 360 * Now that all symbol processing is complete see if any undefined 361 * references still remain. If we observed undefined symbols the 362 * FLG_OF_FATAL bit will be set: If creating a static executable, or a 363 * dynamic executable or shared object with the -zdefs flag set, this 364 * condition is fatal. If creating a shared object with the -Bsymbolic 365 * flag set, this condition is simply a warning. 366 */ 367 if (ofl->ofl_flags & FLG_OF_FATAL) 368 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ARG_SYM_FATAL), 369 ofl->ofl_name); 370 else if (ofl->ofl_flags & FLG_OF_WARN) 371 ld_eprintf(ofl, ERR_WARNING, MSG_INTL(MSG_ARG_SYM_WARN)); 372 373 /* 374 * Guidance: Use -z defs|nodefs when building shared objects. 375 * 376 * ld_sym_validate() will mask this guidance message out unless we are 377 * intended to send it here, so all we need to do is use OFL_GUIDANCE() 378 * to decide whether to issue it or not. 379 */ 380 if (OFL_GUIDANCE(ofl, FLG_OFG_NO_DEFS)) 381 ld_eprintf(ofl, ERR_GUIDANCE, MSG_INTL(MSG_GUIDE_DEFS)); 382 383 /* 384 * Symbol processing was the final step before we start producing the 385 * output object. At this time, if we've seen warnings and the 386 * -z fatal-warnings option is specified, promote them to fatal, which 387 * will cause us to exit without creating an object. 388 * 389 * We didn't do this as the warnings were reported in order to 390 * maximize the number of problems a given link-editor invocation 391 * can diagnose. This is safe, since warnings are by definition events 392 * one can choose to ignore. 393 */ 394 if (((ofl->ofl_flags | save_flg_of_warn) & 395 (FLG_OF_WARN | FLG_OF_FATWARN)) == 396 (FLG_OF_WARN | FLG_OF_FATWARN)) 397 ofl->ofl_flags |= FLG_OF_FATAL; 398 399 /* 400 * If fatal errors occurred in symbol processing, or due to warnings 401 * promoted by -z fatal-warnings, this is the end of the line. 402 */ 403 if (ofl->ofl_flags & FLG_OF_FATAL) 404 return (ld_exit(ofl)); 405 406 /* 407 * Generate any necessary sections. 408 */ 409 if (ld_make_sections(ofl) == S_ERROR) 410 return (ld_exit(ofl)); 411 412 /* 413 * Now that all sections have been added to the output file, determine 414 * whether any mapfile section ordering was specified, and verify that 415 * all mapfile ordering directives have been matched. Issue a warning 416 * for any directives that have not been matched. 417 * Also, if SHF_ORDERED sections exist, set up sort key values. 418 */ 419 if (ofl->ofl_flags & (FLG_OF_OS_ORDER | FLG_OF_KEY)) 420 ld_sec_validate(ofl); 421 422 /* 423 * Having collected all the input data create the initial output file 424 * image, assign virtual addresses to the image, and generate a load 425 * map if the user requested one. 426 */ 427 if (ld_create_outfile(ofl) == S_ERROR) 428 return (ld_exit(ofl)); 429 430 if (ld_update_outfile(ofl) == S_ERROR) 431 return (ld_exit(ofl)); 432 if (ofl->ofl_flags & FLG_OF_GENMAP) 433 ld_map_out(ofl); 434 435 /* 436 * Build relocation sections and perform any relocation updates. 437 */ 438 if (ld_reloc_process(ofl) == S_ERROR) 439 return (ld_exit(ofl)); 440 441 /* 442 * Fill in contents for unwind header (.eh_frame_hdr) 443 */ 444 if (ld_unwind_populate_hdr(ofl) == S_ERROR) 445 return (ld_exit(ofl)); 446 447 /* 448 * Finally create the files elf checksum. 449 */ 450 if (ofl->ofl_checksum) 451 *ofl->ofl_checksum = (Xword)elf_checksum(ofl->ofl_elf); 452 453 /* 454 * If this is a cross link to a target with a different byte 455 * order than the linker, swap the data to the target byte order. 456 */ 457 if (((ofl->ofl_flags1 & FLG_OF1_ENCDIFF) != 0) && 458 (_elf_swap_wrimage(ofl->ofl_elf) != 0)) { 459 ld_eprintf(ofl, ERR_ELF, MSG_INTL(MSG_ELF_SWAP_WRIMAGE), 460 ofl->ofl_name); 461 return (ld_exit(ofl)); 462 } 463 464 /* 465 * We're done, so make sure the updates are flushed to the output file. 466 */ 467 if ((ofl->ofl_size = elf_update(ofl->ofl_welf, ELF_C_WRITE)) == 0) { 468 ld_eprintf(ofl, ERR_ELF, MSG_INTL(MSG_ELF_UPDATE), 469 ofl->ofl_name); 470 return (ld_exit(ofl)); 471 } 472 473 ld_sup_atexit(ofl, 0); 474 475 DBG_CALL(Dbg_statistics_ld(ofl)); 476 DBG_CALL(Dbg_basic_finish(ofl->ofl_lml)); 477 478 /* 479 * Wrap up debug output file if one is open 480 */ 481 dbg_cleanup(); 482 483 /* If any ERR_GUIDANCE messages were issued, add a summary */ 484 if (ofl->ofl_guideflags & FLG_OFG_ISSUED) { 485 ld_eprintf(ofl, ERR_GUIDANCE, MSG_INTL(MSG_GUIDE_SUMMARY)); 486 ofl->ofl_guideflags &= ~FLG_OFG_ISSUED; 487 } 488 489 /* 490 * One final check for any new warnings we found that should fail the 491 * link edit. 492 */ 493 if ((ofl->ofl_flags & (FLG_OF_WARN | FLG_OF_FATWARN)) == 494 (FLG_OF_WARN | FLG_OF_FATWARN)) 495 return (ld_exit(ofl)); 496 497 /* 498 * For performance reasons we didn't used to actually free up the 499 * memory we'd allocated, since it'll be freed on exit. 500 * 501 * These calls does not free nearly as much memory as you would think 502 * they do, unfortunately. 503 */ 504 ld_ofl_cleanup(ofl); 505 libld_free(ofl); 506 return (0); 507 } 508 509 /* 510 * Cleanup an Ifl_desc. 511 */ 512 static void 513 ifl_list_cleanup(APlist *apl) 514 { 515 Aliste idx; 516 Ifl_desc *ifl; 517 518 for (APLIST_TRAVERSE(apl, idx, ifl)) { 519 if (ifl->ifl_elf) 520 (void) elf_end(ifl->ifl_elf); 521 } 522 } 523 524 /* 525 * Cleanup all memory that has been dynamically allocated during libld 526 * processing and elf_end() all Elf descriptors that are still open. 527 */ 528 void 529 ld_ofl_cleanup(Ofl_desc *ofl) 530 { 531 Ar_desc *adp; 532 Aliste idx; 533 534 ifl_list_cleanup(ofl->ofl_objs); 535 ofl->ofl_objs = NULL; 536 ifl_list_cleanup(ofl->ofl_sos); 537 ofl->ofl_sos = NULL; 538 539 for (APLIST_TRAVERSE(ofl->ofl_ars, idx, adp)) { 540 Ar_aux *aup; 541 Elf_Arsym *arsym; 542 543 /* 544 * Free up member information for normally processed archives. 545 * Archives processed under -z allextract have no member 546 * information or symbol table, and members have already been 547 * dealt with as input files. 548 */ 549 if (adp->ad_allextract == TRUE) 550 continue; 551 552 for (arsym = adp->ad_start, aup = adp->ad_aux; 553 (arsym->as_name != NULL); ++arsym, ++aup) { 554 if ((aup->au_mem != NULL) && 555 (aup->au_mem != FLG_ARMEM_PROC)) { 556 (void) elf_end(aup->au_mem->am_elf); 557 558 /* 559 * Null out all entries to this member so 560 * that we don't attempt to elf_end() it again. 561 */ 562 ld_ar_member(adp, arsym, aup, 0); 563 } 564 } 565 (void) elf_end(adp->ad_elf); 566 } 567 ofl->ofl_ars = NULL; 568 569 (void) elf_end(ofl->ofl_elf); 570 (void) elf_end(ofl->ofl_welf); 571 572 /* 573 * Note that we don't free ofl itself here, just its contents. The 574 * ofl itself belongs to the caller. 575 */ 576 } 577