usr/src/cmd/sgs/libld/common/ldmain.c

   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
  29 /*
  30  * Processing of relocatable objects and shared objects.
  31  */
  32
  33 /*
  34  * ld -- link/editor main program
  35  */
  36 #include        <sys/types.h>
  37 #include        <sys/time.h>
  38 #include        <sys/mman.h>
  39 #include        <string.h>
  40 #include        <stdio.h>
  41 #include        <locale.h>
  42 #include        <stdarg.h>
  43 #include        <debug.h>
  44 #include        "msg.h"
  45 #include        "_libld.h"
  46
  47 /*
  48  * All target specific code is referenced via this global variable, which
  49  * is initialized in ld_main(). This allows the linker to function as
  50  * a cross linker, by vectoring to the target-specific code for the
  51  * current target machine.
  52  */
  53 Target          ld_targ;
  54
  55 /*
  56  * A default library search path is used if one was not supplied on the command
  57  * line.  Note: these strings can not use MSG_ORIG() since they are modified as
  58  * part of the path processing.
  59  */
  60 #if     defined(_ELF64)
  61 static char     def_Plibpath[] = "/lib/64:/lib:/usr/lib/64:/usr/lib";
  62 #else
  63 static char     def_Plibpath[] = "/lib/32:/usr/lib/32";
  64 #endif
  65
  66 /*
  67  * A default elf header provides for simplifying diagnostic processing.
  68  */
  69 static Ehdr     def_ehdr = { { ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
  70                             ELFCLASSNONE, ELFDATANONE }, 0, EM_NONE,
  71                             EV_CURRENT };
  72
  73 /*
  74  * ld-centric wrapper on top of veprintf():
  75  * - Accepts output descriptor rather than linkmap list
  76  * - Sets the FLG_OF_FATAL/FLG_OF_WARN flags as necessary
  77  */
  78 void
  79 ld_eprintf(Ofl_desc *ofl, Error error, const char *format, ...)
  80 {
  81         va_list args;
  82
  83         /* Set flag indicating type of error being issued */
  84         switch (error) {
  85         case ERR_NONE:
  86         case ERR_WARNING_NF:
  87                 break;
  88         case ERR_WARNING:
  89                 ofl->ofl_flags |= FLG_OF_WARN;
  90                 break;
  91         case ERR_GUIDANCE:
  92                 if ((ofl->ofl_guideflags & FLG_OFG_ENABLE) == 0)
  93                         return;
  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))) == 0)
 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 = (char *)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         if (ofl->ofl_flags & FLG_OF_FATAL) {
 198                 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ARG_FLAGS));
 199                 /* If any ERR_GUIDANCE messages were issued, add a summary */
 200                 if (ofl->ofl_guideflags & FLG_OFG_ISSUED)
 201                         ld_eprintf(ofl, ERR_GUIDANCE,
 202                             MSG_INTL(MSG_GUIDE_SUMMARY));
 203                 return (1);
 204         }
 205
 206         /*
 207          * At this point a call such as ld -V is considered complete.
 208          */
 209         if (ofl->ofl_flags1 & FLG_OF1_DONE)
 210                 return (0);
 211
 212         /* Initialize signal handler */
 213         ld_init_sighandler(ofl);
 214
 215         /*
 216          * Determine whether any support libraries should be loaded,
 217          * (either through the SGS_SUPPORT environment variable and/or
 218          * through the -S option).
 219          */
 220 #if     defined(_LP64)
 221         if ((sgs_support = getenv(MSG_ORIG(MSG_SGS_SUPPORT_64))) == NULL)
 222 #else
 223         if ((sgs_support = getenv(MSG_ORIG(MSG_SGS_SUPPORT_32))) == NULL)
 224 #endif
 225                 sgs_support = getenv(MSG_ORIG(MSG_SGS_SUPPORT));
 226
 227         if (sgs_support && sgs_support[0]) {
 228                 const char      *sep = MSG_ORIG(MSG_STR_COLON);
 229                 char            *lib;
 230                 char            *lasts;
 231
 232                 DBG_CALL(Dbg_support_req(ofl->ofl_lml, sgs_support,
 233                     DBG_SUP_ENVIRON));
 234                 if ((lib = strtok_r(sgs_support, sep, &lasts)) != NULL) {
 235                         do {
 236                                 if (ld_sup_loadso(ofl, lib) == S_ERROR)
 237                                         return (ld_exit(ofl));
 238                                 DBG_CALL(Dbg_util_nl(ofl->ofl_lml, DBG_NL_STD));
 239
 240                         } while ((lib = strtok_r(NULL, sep, &lasts)) != NULL);
 241                 }
 242         }
 243         if (lib_support) {
 244                 Aliste  idx;
 245                 char    *lib;
 246
 247                 for (APLIST_TRAVERSE(lib_support, idx, lib)) {
 248                         DBG_CALL(Dbg_support_req(ofl->ofl_lml, lib,
 249                             DBG_SUP_CMDLINE));
 250                         if (ld_sup_loadso(ofl, lib) == S_ERROR)
 251                                 return (ld_exit(ofl));
 252                         DBG_CALL(Dbg_util_nl(ofl->ofl_lml, DBG_NL_STD));
 253                 }
 254         }
 255
 256         DBG_CALL(Dbg_ent_print(ofl->ofl_lml,
 257             ofl->ofl_dehdr->e_ident[EI_OSABI], ofl->ofl_dehdr->e_machine,
 258             ofl->ofl_ents));
 259         DBG_CALL(Dbg_seg_list(ofl->ofl_lml,
 260             ofl->ofl_dehdr->e_ident[EI_OSABI], ofl->ofl_dehdr->e_machine,
 261             ofl->ofl_segs));
 262
 263         /*
 264          * The objscnt and soscnt variables were used to estimate the expected
 265          * input files, and size the symbol hash buckets accordingly.  Reset
 266          * these values now, so as to gain an accurate count from pass two, for
 267          * later statistics diagnostics.
 268          */
 269         ofl->ofl_objscnt = ofl->ofl_soscnt = 0;
 270
 271         /*
 272          * Determine whether we can create the file before going any further.
 273          */
 274         if (ld_open_outfile(ofl) == S_ERROR)
 275                 return (ld_exit(ofl));
 276
 277         /*
 278          * If the user didn't supply a library path supply a default.  And, if
 279          * no run-path has been specified (-R), see if the environment variable
 280          * is in use (historic).
 281          */
 282         if (Plibpath == NULL)
 283                 Plibpath = def_Plibpath;
 284
 285         if (ofl->ofl_rpath == NULL) {
 286                 char    *rpath;
 287
 288                 if (((rpath = getenv(MSG_ORIG(MSG_LD_RUN_PATH))) != NULL) &&
 289                     rpath[0])
 290                         ofl->ofl_rpath = rpath;
 291         }
 292
 293         /*
 294          * Argument pass two.  Input all libraries and objects.
 295          */
 296         if (ld_lib_setup(ofl) == S_ERROR)
 297                 return (ld_exit(ofl));
 298
 299         /*
 300          * Call ld_start() with the etype of our output file and the
 301          * output file name.
 302          */
 303         if (ofl->ofl_flags & (FLG_OF_SHAROBJ | FLG_OF_PIE))
 304                 etype = ET_DYN;
 305         else if (ofl->ofl_flags & FLG_OF_RELOBJ)
 306                 etype = ET_REL;
 307         else
 308                 etype = ET_EXEC;
 309
 310         ld_sup_start(ofl, etype, argv[0]);
 311
 312         /*
 313          * Process all input files.
 314          */
 315         if (ld_process_files(ofl, argc, argv) == S_ERROR)
 316                 return (ld_exit(ofl));
 317         if (ofl->ofl_flags & FLG_OF_FATAL) {
 318                 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ARG_FILES),
 319                     ofl->ofl_name);
 320                 return (ld_exit(ofl));
 321         }
 322
 323         ld_sup_input_done(ofl);
 324
 325         /*
 326          * Now that all input section processing is complete, validate and
 327          * process any SHT_SUNW_move sections.
 328          */
 329         if (ofl->ofl_ismove && (ld_process_move(ofl) == S_ERROR))
 330                 return (ld_exit(ofl));
 331
 332         /*
 333          * Before validating all symbols count the number of relocation entries.
 334          * If copy relocations exist, COMMON symbols must be generated which are
 335          * assigned to the executables .bss.  During sym_validate() the actual
 336          * size and alignment of the .bss is calculated.  Doing things in this
 337          * order reduces the number of symbol table traversals required (however
 338          * it does take a little longer for the user to be told of any undefined
 339          * symbol errors).
 340          */
 341         if (ld_reloc_init(ofl) == S_ERROR)
 342                 return (ld_exit(ofl));
 343
 344         /*
 345          * We need to know if FLG_OF_WARN is currently set, in case
 346          * we need to honor a -z fatal-warnings request. However, we also
 347          * need to know if a warning due to symbol validation results from
 348          * the upcoming call to ld_sym_validate() in order to issue the
 349          * appropriate message for it. So we save the current value,
 350          * and clear the main flag.
 351          */
 352         save_flg_of_warn = ofl->ofl_flags & FLG_OF_WARN;
 353         ofl->ofl_flags &= ~FLG_OF_WARN;
 354
 355         if (ld_sym_validate(ofl) == S_ERROR)
 356                 return (ld_exit(ofl));
 357
 358         /*
 359          * Now that all symbol processing is complete see if any undefined
 360          * references still remain.  If we observed undefined symbols the
 361          * FLG_OF_FATAL bit will be set:  If creating a static executable, or a
 362          * dynamic executable or shared object with the -zdefs flag set, this
 363          * condition is fatal.  If creating a shared object with the -Bsymbolic
 364          * flag set, this condition is simply a warning.
 365          */
 366         if (ofl->ofl_flags & FLG_OF_FATAL)
 367                 ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_ARG_SYM_FATAL),
 368                     ofl->ofl_name);
 369         else if (ofl->ofl_flags & FLG_OF_WARN)
 370                 ld_eprintf(ofl, ERR_WARNING, MSG_INTL(MSG_ARG_SYM_WARN));
 371
 372         /*
 373          * Guidance: Use -z defs|nodefs when building shared objects.
 374          *
 375          * ld_sym_validate() will mask this guidance message out unless we are
 376          * intended to send it here, so all we need to do is use OFL_GUIDANCE()
 377          * to decide whether to issue it or not.
 378          */
 379         if (OFL_GUIDANCE(ofl, FLG_OFG_NO_DEFS))
 380                 ld_eprintf(ofl, ERR_GUIDANCE, MSG_INTL(MSG_GUIDE_DEFS));
 381
 382         /*
 383          * Symbol processing was the final step before we start producing the
 384          * output object. At this time, if we've seen warnings and the
 385          * -z fatal-warnings option is specified, promote them to fatal, which
 386          * will cause us to exit without creating an object.
 387          *
 388          * We didn't do this as the warnings were reported in order to
 389          * maximize the number of problems a given link-editor invocation
 390          * can diagnose. This is safe, since warnings are by definition events
 391          * one can choose to ignore.
 392          */
 393         if (((ofl->ofl_flags | save_flg_of_warn) &
 394             (FLG_OF_WARN | FLG_OF_FATWARN)) ==
 395             (FLG_OF_WARN | FLG_OF_FATWARN))
 396                 ofl->ofl_flags |= FLG_OF_FATAL;
 397
 398         /*
 399          * If fatal errors occurred in symbol processing, or due to warnings
 400          * promoted by -z fatal-warnings, this is the end of the line.
 401          */
 402         if (ofl->ofl_flags & FLG_OF_FATAL)
 403                 return (ld_exit(ofl));
 404
 405         /*
 406          * Generate any necessary sections.
 407          */
 408         if (ld_make_sections(ofl) == S_ERROR)
 409                 return (ld_exit(ofl));
 410
 411         /*
 412          * Now that all sections have been added to the output file, determine
 413          * whether any mapfile section ordering was specified, and verify that
 414          * all mapfile ordering directives have been matched.  Issue a warning
 415          * for any directives that have not been matched.
 416          * Also, if SHF_ORDERED sections exist, set up sort key values.
 417          */
 418         if (ofl->ofl_flags & (FLG_OF_OS_ORDER | FLG_OF_KEY))
 419                 ld_sec_validate(ofl);
 420
 421         /*
 422          * Having collected all the input data create the initial output file
 423          * image, assign virtual addresses to the image, and generate a load
 424          * map if the user requested one.
 425          */
 426         if (ld_create_outfile(ofl) == S_ERROR)
 427                 return (ld_exit(ofl));
 428
 429         if (ld_update_outfile(ofl) == S_ERROR)
 430                 return (ld_exit(ofl));
 431         if (ofl->ofl_flags & FLG_OF_GENMAP)
 432                 ld_map_out(ofl);
 433
 434         /*
 435          * Build relocation sections and perform any relocation updates.
 436          */
 437         if (ld_reloc_process(ofl) == S_ERROR)
 438                 return (ld_exit(ofl));
 439
 440         /*
 441          * Fill in contents for unwind header (.eh_frame_hdr)
 442          */
 443         if (ld_unwind_populate_hdr(ofl) == S_ERROR)
 444                 return (ld_exit(ofl));
 445
 446         /*
 447          * Finally create the files elf checksum.
 448          */
 449         if (ofl->ofl_checksum)
 450                 *ofl->ofl_checksum = (Xword)elf_checksum(ofl->ofl_elf);
 451
 452         /*
 453          * If this is a cross link to a target with a different byte
 454          * order than the linker, swap the data to the target byte order.
 455          */
 456         if (((ofl->ofl_flags1 & FLG_OF1_ENCDIFF) != 0) &&
 457             (_elf_swap_wrimage(ofl->ofl_elf) != 0)) {
 458                 ld_eprintf(ofl, ERR_ELF, MSG_INTL(MSG_ELF_SWAP_WRIMAGE),
 459                     ofl->ofl_name);
 460                 return (ld_exit(ofl));
 461         }
 462
 463         /*
 464          * We're done, so make sure the updates are flushed to the output file.
 465          */
 466         if ((ofl->ofl_size = elf_update(ofl->ofl_welf, ELF_C_WRITE)) == 0) {
 467                 ld_eprintf(ofl, ERR_ELF, MSG_INTL(MSG_ELF_UPDATE),
 468                     ofl->ofl_name);
 469                 return (ld_exit(ofl));
 470         }
 471
 472         ld_sup_atexit(ofl, 0);
 473
 474         DBG_CALL(Dbg_statistics_ld(ofl));
 475         DBG_CALL(Dbg_basic_finish(ofl->ofl_lml));
 476
 477         /*
 478          * Wrap up debug output file if one is open
 479          */
 480         dbg_cleanup();
 481
 482         /* If any ERR_GUIDANCE messages were issued, add a summary */
 483         if (ofl->ofl_guideflags & FLG_OFG_ISSUED)
 484                 ld_eprintf(ofl, ERR_GUIDANCE, MSG_INTL(MSG_GUIDE_SUMMARY));
 485
 486         /*
 487          * For performance reasons we don't actually free up the memory we've
 488          * allocated, it will be freed when we exit.
 489          *
 490          * But the below line can be uncommented if/when we want to measure how
 491          * our memory consumption and freeing are doing.  We should be able to
 492          * free all the memory that has been allocated as part of the link-edit
 493          * process.
 494          */
 495         /* ld_ofl_cleanup(ofl); */
 496         return (0);
 497 }
 498
 499 /*
 500  * Cleanup an Ifl_desc.
 501  */
 502 static void
 503 ifl_list_cleanup(APlist *apl)
 504 {
 505         Aliste          idx;
 506         Ifl_desc        *ifl;
 507
 508         for (APLIST_TRAVERSE(apl, idx, ifl)) {
 509                 if (ifl->ifl_elf)
 510                         (void) elf_end(ifl->ifl_elf);
 511         }
 512 }
 513
 514 /*
 515  * Cleanup all memory that has been dynamically allocated during libld
 516  * processing and elf_end() all Elf descriptors that are still open.
 517  */
 518 void
 519 ld_ofl_cleanup(Ofl_desc *ofl)
 520 {
 521         Ld_heap         *chp, *php;
 522         Ar_desc         *adp;
 523         Aliste          idx;
 524
 525         ifl_list_cleanup(ofl->ofl_objs);
 526         ofl->ofl_objs = NULL;
 527         ifl_list_cleanup(ofl->ofl_sos);
 528         ofl->ofl_sos = NULL;
 529
 530         for (APLIST_TRAVERSE(ofl->ofl_ars, idx, adp)) {
 531                 Ar_aux          *aup;
 532                 Elf_Arsym       *arsym;
 533
 534                 for (arsym = adp->ad_start, aup = adp->ad_aux;
 535                     arsym->as_name; ++arsym, ++aup) {
 536                         if ((aup->au_mem) && (aup->au_mem != FLG_ARMEM_PROC)) {
 537                                 (void) elf_end(aup->au_mem->am_elf);
 538
 539                                 /*
 540                                  * Null out all entries to this member so
 541                                  * that we don't attempt to elf_end() it again.
 542                                  */
 543                                 ld_ar_member(adp, arsym, aup, 0);
 544                         }
 545                 }
 546                 (void) elf_end(adp->ad_elf);
 547         }
 548         ofl->ofl_ars = NULL;
 549
 550         (void) elf_end(ofl->ofl_elf);
 551         (void) elf_end(ofl->ofl_welf);
 552
 553         for (chp = ld_heap, php = NULL; chp; php = chp, chp = chp->lh_next) {
 554                 if (php)
 555                         (void) munmap((void *)php,
 556                             (size_t)php->lh_end - (size_t)php);
 557         }
 558         if (php)
 559                 (void) munmap((void *)php, (size_t)php->lh_end - (size_t)php);
 560
 561         ld_heap = NULL;
 562 }