1 /* Copyright (C) 2001, 2002, 2003, 2005, 2006, 2008, 2009 Red Hat, Inc. 2 This file is part of elfutils. 3 Written by Ulrich Drepper <drepper (at) redhat.com>, 2001. 4 5 This file is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 elfutils is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18 #ifndef LD_H 19 #define LD_H 1 20 21 #include <dlfcn.h> 22 #include <obstack.h> 23 #include <stdbool.h> 24 #include <stdio.h> 25 #include "xelf.h" 26 27 28 /* Recommended size of the buffer passed to ld_strerror. */ 29 #define ERRBUFSIZE (512) 30 31 /* Character used to introduce version name after symbol. */ 32 #define VER_CHR '@' 33 34 35 /* Methods for handling archives. */ 36 enum extract_rule 37 { 38 defaultextract, /* Weak references don't cause archive member to 39 be used. */ 40 weakextract, /* Weak references cause archive member to be 41 extracted. */ 42 allextract /* Extract all archive members regardless of 43 references (aka whole-archive). */ 44 }; 45 46 47 /* Type of output file. */ 48 enum file_type 49 { 50 no_file_type = 0, /* None selected so far. */ 51 executable_file_type, /* Executable. */ 52 dso_file_type, /* DSO. */ 53 dso_needed_file_type, /* DSO introduced by DT_NEEDED. */ 54 relocatable_file_type, /* Relocatable object file. */ 55 archive_file_type /* Archive (input only). */ 56 }; 57 58 59 struct usedfiles 60 { 61 /* The next file given at the command line. */ 62 struct usedfiles *next; 63 /* Nonzero if this file is the beginning of a group. */ 64 bool group_start; 65 /* Nonzero if this file is the end of a group. */ 66 bool group_end; 67 /* Pointer to the beginning of the group. It is necessary to 68 explain why we cannot simply use the 'next' pointer and have a 69 circular single-linked list like in many cases. The problem is 70 that the last archive of the group, if it is the last file of the 71 group, contains the only existing pointer to the next file we 72 have to look at. All files are initially connected via the 73 'next' pointer in a single-linked list. Therefore we cannot 74 overwrite this value. It instead will be used once the group is 75 handled and we go on processing the rest of the files. */ 76 struct usedfiles *group_backref; 77 78 /* Name/path of the file. */ 79 const char *fname; 80 /* Resolved file name. */ 81 const char *rfname; 82 /* Name used as reference in DT_NEEDED entries. This is normally 83 the SONAME. If it is missing it's normally the fname above. */ 84 const char *soname; 85 /* Handle for the SONAME in the string table. */ 86 struct Ebl_Strent *sonameent; 87 88 /* Help to identify duplicates. */ 89 dev_t dev; 90 ino_t ino; 91 92 enum 93 { 94 not_opened, 95 opened, 96 in_archive, 97 closed 98 } status; 99 100 /* How to extract elements from archives. */ 101 enum extract_rule extract_rule; 102 103 /* Lazy-loading rule. */ 104 bool lazyload; 105 106 /* If this is a DSO the flag indicates whether the file is directly 107 used in a reference. */ 108 bool used; 109 110 /* True when file should be added to DT_NEEDED list only when 111 directly referenced. */ 112 bool as_needed; 113 114 /* If nonzero this is the archive sequence number which can be used to 115 determine whether back refernces from -( -) or GROUP statements 116 have to be followed. */ 117 int archive_seq; 118 119 /* Pointer to the record for the archive containing this file. */ 120 struct usedfiles *archive_file; 121 122 /* Type of file. We have to distinguish these types since they 123 are searched for differently. */ 124 enum file_type file_type; 125 /* This is the ELF library handle for this file. */ 126 Elf *elf; 127 128 /* The ELF header. */ 129 #if NATIVE_ELF != 0 130 XElf_Ehdr *ehdr; 131 # define FILEINFO_EHDR(fi) (*(fi)) 132 #else 133 XElf_Ehdr ehdr; 134 # define FILEINFO_EHDR(fi) (fi) 135 #endif 136 137 /* Index of the section header string table section. We use a 138 separate field and not the e_shstrndx field in the ELF header 139 since in case of a file with more than 64000 sections the index 140 might be stored in the section header of section zero. The 141 elf_getshdrstrndx() function can find the value but it is too 142 costly to repeat this call over and over. */ 143 size_t shstrndx; 144 145 /* Info about the sections of the file. */ 146 struct scninfo 147 { 148 /* Handle for the section. Note that we can store a section 149 handle here because the file is not changing. This together 150 with the knowledge about the libelf library is enough for us to 151 assume the section reference remains valid at all times. */ 152 Elf_Scn *scn; 153 /* Section header. */ 154 #if NATIVE_ELF != 0 155 XElf_Shdr *shdr; 156 # define SCNINFO_SHDR(si) (*(si)) 157 #else 158 XElf_Shdr shdr; 159 # define SCNINFO_SHDR(si) (si) 160 #endif 161 /* Offset of this files section in the combined section. */ 162 XElf_Off offset; 163 /* Index of the section in the output file. */ 164 Elf32_Word outscnndx; 165 /* Index of the output section in the 'allsection' array. */ 166 Elf32_Word allsectionsidx; 167 /* True if the section is used. */ 168 bool used; 169 /* True if section is an unused COMDAT section. */ 170 bool unused_comdat; 171 /* True if this is a COMDAT group section. */ 172 bool comdat_group; 173 /* Section group number. This is the index of the SHT_GROUP section. */ 174 Elf32_Word grpid; 175 /* Pointer back to the containing file information structure. */ 176 struct usedfiles *fileinfo; 177 /* List of symbols in this section (set only for merge-able sections 178 and group sections). */ 179 struct symbol *symbols; 180 /* Size of relocations in this section. Only used for relocation 181 sections. */ 182 size_t relsize; 183 /* Pointer to next section which is put in the given output 184 section. */ 185 struct scninfo *next; 186 } *scninfo; 187 188 /* List of section group sections. */ 189 struct scninfo *groups; 190 191 /* The symbol table section. 192 193 XXX Maybe support for more than one symbol table is needed. */ 194 Elf_Data *symtabdata; 195 /* Extra section index table section. */ 196 Elf_Data *xndxdata; 197 /* Dynamic symbol table section. */ 198 Elf_Data *dynsymtabdata; 199 /* The version number section. */ 200 Elf_Data *versymdata; 201 /* The defined versions. */ 202 Elf_Data *verdefdata; 203 /* Number of versions defined. */ 204 size_t nverdef; 205 /* True if the version with the given index number is used in the 206 output. */ 207 XElf_Versym *verdefused; 208 /* How many versions are used. */ 209 size_t nverdefused; 210 /* Handle for name of the version. */ 211 struct Ebl_Strent **verdefent; 212 /* The needed versions. */ 213 Elf_Data *verneeddata; 214 /* String table section associated with the symbol table. */ 215 Elf32_Word symstridx; 216 /* String table section associated with the dynamic symbol table. */ 217 Elf32_Word dynsymstridx; 218 /* Number of entries in the symbol table. */ 219 size_t nsymtab; 220 size_t nlocalsymbols; 221 size_t ndynsymtab; 222 /* Dynamic section. */ 223 Elf_Scn *dynscn; 224 225 /* Indirection table for the symbols defined here. */ 226 Elf32_Word *symindirect; 227 Elf32_Word *dynsymindirect; 228 /* For undefined or common symbols we need a reference to the symbol 229 record. */ 230 struct symbol **symref; 231 struct symbol **dynsymref; 232 233 /* This is the file descriptor. The value is -1 if the descriptor 234 was already closed. This can happen if we needed file descriptors 235 to open new files. */ 236 int fd; 237 /* This flag is true if the descriptor was passed to the generic 238 functions from somewhere else. This is an implementation detail; 239 no machine-specific code must use this flag. */ 240 bool fd_passed; 241 242 /* True if any of the sections is merge-able. */ 243 bool has_merge_sections; 244 }; 245 246 247 /* Functions to test for the various types of files we handle. */ 248 static inline int 249 ld_file_rel_p (struct usedfiles *file) 250 { 251 return (elf_kind (file->elf) == ELF_K_ELF 252 && FILEINFO_EHDR (file->ehdr).e_type == ET_REL); 253 } 254 255 static inline int 256 ld_file_dso_p (struct usedfiles *file) 257 { 258 return (elf_kind (file->elf) == ELF_K_ELF 259 && FILEINFO_EHDR (file->ehdr).e_type == ET_DYN); 260 } 261 262 static inline int 263 ld_file_ar_p (struct usedfiles *file) 264 { 265 return elf_kind (file->elf) == ELF_K_AR; 266 } 267 268 269 struct pathelement 270 { 271 /* The next path to search. */ 272 struct pathelement *next; 273 /* The path name. */ 274 const char *pname; 275 /* Larger than zero if the directory exists, smaller than zero if not, 276 zero if it is not yet known. */ 277 int exist; 278 }; 279 280 281 /* Forward declaration. */ 282 struct ld_state; 283 284 285 /* Callback functions. */ 286 struct callbacks 287 { 288 /* Library names passed to the linker as -lXXX represent files named 289 libXXX.YY. The YY part can have different forms, depending on the 290 architecture. The generic set is .so and .a (in this order). */ 291 const char **(*lib_extensions) (struct ld_state *) 292 __attribute__ ((__const__)); 293 #define LIB_EXTENSION(state) \ 294 DL_CALL_FCT ((state)->callbacks.lib_extensions, (state)) 295 296 /* Process the given file. If the file is not yet open, open it. 297 The first parameter is a file descriptor for the file which can 298 be -1 to indicate the file has not yet been found. The second 299 parameter describes the file to be opened, the last one is the 300 state of the linker which among other information contain the 301 paths we look at.*/ 302 int (*file_process) (int fd, struct usedfiles *, struct ld_state *, 303 struct usedfiles **); 304 #define FILE_PROCESS(fd, file, state, nextp) \ 305 DL_CALL_FCT ((state)->callbacks.file_process, (fd, file, state, nextp)) 306 307 /* Close the given file. */ 308 int (*file_close) (struct usedfiles *, struct ld_state *); 309 #define FILE_CLOSE(file, state) \ 310 DL_CALL_FCT ((state)->callbacks.file_close, (file, state)) 311 312 /* Create the output sections now. This requires knowledge about 313 all the sections we will need. It may be necessary to sort the 314 sections in the order they are supposed to appear in the 315 executable. The sorting use many different kinds of information 316 to optimize the resulting binary. Important is to respect 317 segment boundaries and the needed alignment. The mode of the 318 segments will be determined afterwards automatically by the 319 output routines. */ 320 void (*create_sections) (struct ld_state *); 321 #define CREATE_SECTIONS(state) \ 322 DL_CALL_FCT ((state)->callbacks.create_sections, (state)) 323 324 /* Determine whether we have any non-weak unresolved references left. */ 325 int (*flag_unresolved) (struct ld_state *); 326 #define FLAG_UNRESOLVED(state) \ 327 DL_CALL_FCT ((state)->callbacks.flag_unresolved, (state)) 328 329 /* Create the sections which are generated by the linker and are not 330 present in the input file. */ 331 void (*generate_sections) (struct ld_state *); 332 #define GENERATE_SECTIONS(state) \ 333 DL_CALL_FCT ((state)->callbacks.generate_sections, (state)) 334 335 /* Open the output file. The file name is given or "a.out". We 336 create as much of the ELF structure as possible. */ 337 int (*open_outfile) (struct ld_state *, int, int, int); 338 #define OPEN_OUTFILE(state, machine, class, data) \ 339 DL_CALL_FCT ((state)->callbacks.open_outfile, (state, machine, class, data)) 340 341 /* Create the data for the output file. */ 342 int (*create_outfile) (struct ld_state *); 343 #define CREATE_OUTFILE(state) \ 344 DL_CALL_FCT ((state)->callbacks.create_outfile, (state)) 345 346 /* Process a relocation section. */ 347 void (*relocate_section) (struct ld_state *, Elf_Scn *, struct scninfo *, 348 const Elf32_Word *); 349 #define RELOCATE_SECTION(state, outscn, first, dblindirect) \ 350 DL_CALL_FCT ((state)->callbacks.relocate_section, (state, outscn, first, \ 351 dblindirect)) 352 353 /* Allocate a data buffer for the relocations of the given output 354 section. */ 355 void (*count_relocations) (struct ld_state *, struct scninfo *); 356 #define COUNT_RELOCATIONS(state, scninfo) \ 357 DL_CALL_FCT ((state)->callbacks.count_relocations, (state, scninfo)) 358 359 /* Create relocations for executable or DSO. */ 360 void (*create_relocations) (struct ld_state *, const Elf32_Word *); 361 #define CREATE_RELOCATIONS(state, dlbindirect) \ 362 DL_CALL_FCT ((state)->callbacks.create_relocations, (state, dblindirect)) 363 364 /* Finalize the output file. */ 365 int (*finalize) (struct ld_state *); 366 #define FINALIZE(state) \ 367 DL_CALL_FCT ((state)->callbacks.finalize, (state)) 368 369 /* Check whether special section number is known. */ 370 bool (*special_section_number_p) (struct ld_state *, size_t); 371 #define SPECIAL_SECTION_NUMBER_P(state, number) \ 372 DL_CALL_FCT ((state)->callbacks.special_section_number_p, (state, number)) 373 374 /* Check whether section type is known. */ 375 bool (*section_type_p) (struct ld_state *, XElf_Word); 376 #define SECTION_TYPE_P(state, type) \ 377 DL_CALL_FCT ((state)->callbacks.section_type_p, (state, type)) 378 379 /* Return section flags for .dynamic section. */ 380 XElf_Xword (*dynamic_section_flags) (struct ld_state *); 381 #define DYNAMIC_SECTION_FLAGS(state) \ 382 DL_CALL_FCT ((state)->callbacks.dynamic_section_flags, (state)) 383 384 /* Create the data structures for the .plt section and initialize it. */ 385 void (*initialize_plt) (struct ld_state *, Elf_Scn *scn); 386 #define INITIALIZE_PLT(state, scn) \ 387 DL_CALL_FCT ((state)->callbacks.initialize_plt, (state, scn)) 388 389 /* Create the data structures for the .rel.plt section and initialize it. */ 390 void (*initialize_pltrel) (struct ld_state *, Elf_Scn *scn); 391 #define INITIALIZE_PLTREL(state, scn) \ 392 DL_CALL_FCT ((state)->callbacks.initialize_pltrel, (state, scn)) 393 394 /* Finalize the .plt section the what belongs to them. */ 395 void (*finalize_plt) (struct ld_state *, size_t, size_t, struct symbol **); 396 #define FINALIZE_PLT(state, nsym, nsym_dyn, ndxtosym) \ 397 DL_CALL_FCT ((state)->callbacks.finalize_plt, (state, nsym, nsym_dyn, \ 398 ndxtosym)) 399 400 /* Create the data structures for the .got section and initialize it. */ 401 void (*initialize_got) (struct ld_state *, Elf_Scn *scn); 402 #define INITIALIZE_GOT(state, scn) \ 403 DL_CALL_FCT ((state)->callbacks.initialize_got, (state, scn)) 404 405 /* Create the data structures for the .got.plt section and initialize it. */ 406 void (*initialize_gotplt) (struct ld_state *, Elf_Scn *scn); 407 #define INITIALIZE_GOTPLT(state, scn) \ 408 DL_CALL_FCT ((state)->callbacks.initialize_gotplt, (state, scn)) 409 410 /* Return the tag corresponding to the native relocation type for 411 the platform. */ 412 int (*rel_type) (struct ld_state *); 413 #define REL_TYPE(state) \ 414 DL_CALL_FCT ((state)->callbacks.rel_type, (state)) 415 }; 416 417 418 /* Structure for symbol representation. This data structure is used a 419 lot, so size is important. */ 420 struct symbol 421 { 422 /* Symbol name. */ 423 const char *name; 424 /* Size of the object. */ 425 XElf_Xword size; 426 /* Index of the symbol in the symbol table of the object. */ 427 size_t symidx; 428 /* Index of the symbol in the symbol table of the output file. */ 429 size_t outsymidx; 430 431 /* Description where the symbol is found/needed. */ 432 size_t scndx; 433 struct usedfiles *file; 434 /* Index of the symbol table. */ 435 Elf32_Word symscndx; 436 437 /* Index of the symbol in the dynamic symbol table of the output 438 file. Note that the value only needs to be 16 bit wide since 439 there cannot be more sections in an executable or DSO. */ 440 unsigned int outdynsymidx:16; 441 442 /* Type of the symbol. */ 443 unsigned int type:4; 444 /* Various flags. */ 445 unsigned int defined:1; 446 unsigned int common:1; 447 unsigned int weak:1; 448 unsigned int added:1; 449 unsigned int merged:1; 450 unsigned int local:1; 451 unsigned int hidden:1; 452 /* Nonzero if the symbol is on the from_dso list. */ 453 unsigned int on_dsolist:1; 454 /* Nonzero if symbol needs copy relocation, reset when the 455 relocation has been created. */ 456 unsigned int need_copy:1; 457 unsigned int in_dso:1; 458 459 union 460 { 461 /* Pointer to the handle created by the functions which create 462 merged section contents. We use 'void *' because there are 463 different implementations used. */ 464 void *handle; 465 XElf_Addr value; 466 } merge; 467 468 /* Pointer to next/previous symbol on whatever list the symbol is. */ 469 struct symbol *next; 470 struct symbol *previous; 471 /* Pointer to next symbol of the same section (only set for merge-able 472 sections). */ 473 struct symbol *next_in_scn; 474 }; 475 476 477 /* Get the definition for the symbol table. */ 478 #include <symbolhash.h> 479 480 /* Simple single linked list of file names. */ 481 struct filename_list 482 { 483 const char *name; 484 struct usedfiles *real; 485 struct filename_list *next; 486 bool group_start; 487 bool group_end; 488 bool as_needed; 489 }; 490 491 492 /* Data structure to describe expression in linker script. */ 493 struct expression 494 { 495 enum expression_tag 496 { 497 exp_num, 498 exp_sizeof_headers, 499 exp_pagesize, 500 exp_id, 501 exp_mult, 502 exp_div, 503 exp_mod, 504 exp_plus, 505 exp_minus, 506 exp_and, 507 exp_or, 508 exp_align 509 } tag; 510 511 union 512 { 513 uintmax_t num; 514 struct expression *child; 515 struct 516 { 517 struct expression *left; 518 struct expression *right; 519 } binary; 520 const char *str; 521 } val; 522 }; 523 524 525 /* Data structure for section name with flags. */ 526 struct input_section_name 527 { 528 const char *name; 529 bool sort_flag; 530 }; 531 532 /* File name mask with section name. */ 533 struct filemask_section_name 534 { 535 const char *filemask; 536 const char *excludemask; 537 struct input_section_name *section_name; 538 bool keep_flag; 539 }; 540 541 /* Data structure for assignments. */ 542 struct assignment 543 { 544 const char *variable; 545 struct expression *expression; 546 struct symbol *sym; 547 bool provide_flag; 548 }; 549 550 551 /* Data structure describing input for an output section. */ 552 struct input_rule 553 { 554 enum 555 { 556 input_section, 557 input_assignment 558 } tag; 559 560 union 561 { 562 struct assignment *assignment; 563 struct filemask_section_name *section; 564 } val; 565 566 struct input_rule *next; 567 }; 568 569 570 /* Data structure to describe output section. */ 571 struct output_section 572 { 573 const char *name; 574 struct input_rule *input; 575 XElf_Addr max_alignment; 576 bool ignored; 577 }; 578 579 580 /* Data structure to describe output file format. */ 581 struct output_rule 582 { 583 enum 584 { 585 output_section, 586 output_assignment 587 } tag; 588 589 union 590 { 591 struct assignment *assignment; 592 struct output_section section; 593 } val; 594 595 struct output_rule *next; 596 }; 597 598 599 /* List of all the segments the linker script describes. */ 600 struct output_segment 601 { 602 int mode; 603 struct output_rule *output_rules; 604 struct output_segment *next; 605 606 XElf_Off offset; 607 XElf_Addr addr; 608 XElf_Xword align; 609 }; 610 611 612 /* List of identifiers. */ 613 struct id_list 614 { 615 union 616 { 617 enum id_type 618 { 619 id_str, /* Normal string. */ 620 id_all, /* "*", matches all. */ 621 id_wild /* Globbing wildcard string. */ 622 } id_type; 623 struct 624 { 625 bool local; 626 const char *versionname; 627 } s; 628 } u; 629 const char *id; 630 struct id_list *next; 631 }; 632 633 634 /* Version information. */ 635 struct version 636 { 637 struct version *next; 638 struct id_list *local_names; 639 struct id_list *global_names; 640 const char *versionname; 641 const char *parentname; 642 }; 643 644 645 /* Head for list of sections. */ 646 struct scnhead 647 { 648 /* Name of the sections. */ 649 const char *name; 650 651 /* Accumulated flags for the sections. */ 652 XElf_Xword flags; 653 654 /* Type of the sections. */ 655 XElf_Word type; 656 657 /* Entry size. If there are differencs between the sections with 658 the same name this field contains 1. */ 659 XElf_Word entsize; 660 661 /* If non-NULL pointer to group signature. */ 662 const char *grp_signature; 663 664 /* Maximum alignment for all sections. */ 665 XElf_Word align; 666 667 /* Distinguish between normal sections coming from the input file 668 and sections generated by the linker. */ 669 enum scn_kind 670 { 671 scn_normal, /* Section from the input file(s). */ 672 scn_dot_interp, /* Generated .interp section. */ 673 scn_dot_got, /* Generated .got section. */ 674 scn_dot_gotplt, /* Generated .got.plt section. */ 675 scn_dot_dynrel, /* Generated .rel.dyn section. */ 676 scn_dot_dynamic, /* Generated .dynamic section. */ 677 scn_dot_dynsym, /* Generated .dynsym section. */ 678 scn_dot_dynstr, /* Generated .dynstr section. */ 679 scn_dot_hash, /* Generated .hash section. */ 680 scn_dot_gnu_hash, /* Generated .gnu.hash section. */ 681 scn_dot_plt, /* Generated .plt section. */ 682 scn_dot_pltrel, /* Generated .rel.plt section. */ 683 scn_dot_version, /* Generated .gnu.version section. */ 684 scn_dot_version_r, /* Generated .gnu.version_r section. */ 685 scn_dot_note_gnu_build_id /* Generated .note.gnu.build-id section. */ 686 } kind; 687 688 /* True is the section is used in the output. */ 689 bool used; 690 691 /* Total size (only determined this way for relocation sections). */ 692 size_t relsize; 693 694 /* Filled in by the section sorting to indicate which segment the 695 section goes in. */ 696 int segment_nr; 697 698 /* Index of the output section. We cannot store the section handle 699 directly here since the handle is a pointer in a dynamically 700 allocated table which might move if it becomes too small for all 701 the sections. Using the index the correct value can be found at 702 all times. */ 703 XElf_Word scnidx; 704 705 /* Index of the STT_SECTION entry for this section in the symbol 706 table. */ 707 XElf_Word scnsymidx; 708 709 /* Address of the section in the output file. */ 710 XElf_Addr addr; 711 712 /* Handle for the section name in the output file's section header 713 string table. */ 714 struct Ebl_Strent *nameent; 715 716 /* Tail of list of symbols for this section. Only set if the 717 section is merge-able. */ 718 struct symbol *symbols; 719 720 /* Pointer to last section. */ 721 struct scninfo *last; 722 }; 723 724 725 /* Define hash table for sections. */ 726 #include <sectionhash.h> 727 728 /* Define hash table for version symbols. */ 729 #include <versionhash.h> 730 731 732 /* State of the linker. */ 733 struct ld_state 734 { 735 /* ELF backend library handle. */ 736 Ebl *ebl; 737 738 /* List of all archives participating, in this order. */ 739 struct usedfiles *archives; 740 /* End of the list. */ 741 struct usedfiles *tailarchives; 742 /* If nonzero we are looking for the beginning of a group. */ 743 bool group_start_requested; 744 /* Pointer to the archive starting the group. */ 745 struct usedfiles *group_start_archive; 746 747 /* List of the DSOs we found. */ 748 struct usedfiles *dsofiles; 749 /* Number of DSO files. */ 750 size_t ndsofiles; 751 /* Ultimate list of object files which are linked in. */ 752 struct usedfiles *relfiles; 753 754 /* List the DT_NEEDED DSOs. */ 755 struct usedfiles *needed; 756 757 /* Temporary storage for the parser. */ 758 struct filename_list *srcfiles; 759 760 /* List of all the paths to look at. */ 761 struct pathelement *paths; 762 /* Tail of the list. */ 763 struct pathelement *tailpaths; 764 765 /* User provided paths for lookup of DSOs. */ 766 struct pathelement *rpath; 767 struct pathelement *rpath_link; 768 struct pathelement *runpath; 769 struct pathelement *runpath_link; 770 struct Ebl_Strent *rxxpath_strent; 771 int rxxpath_tag; 772 773 /* From the environment variable LD_LIBRARY_PATH. */ 774 struct pathelement *ld_library_path1; 775 struct pathelement *ld_library_path2; 776 777 /* Name of the output file. */ 778 const char *outfname; 779 /* Name of the temporary file we initially create. */ 780 const char *tempfname; 781 /* File descriptor opened for the output file. */ 782 int outfd; 783 /* The ELF descriptor for the output file. */ 784 Elf *outelf; 785 786 /* Type of output file. */ 787 enum file_type file_type; 788 789 /* Is this a system library or not. */ 790 bool is_system_library; 791 792 /* Page size to be assumed for the binary. */ 793 size_t pagesize; 794 795 /* Name of the interpreter for dynamically linked objects. */ 796 const char *interp; 797 /* Index of the .interp section. */ 798 Elf32_Word interpscnidx; 799 800 /* Optimization level. */ 801 unsigned long int optlevel; 802 803 /* If true static linking is requested. */ 804 bool statically; 805 806 /* If true, add DT_NEEDED entries for following files if they are 807 needed. */ 808 bool as_needed; 809 810 /* How to extract elements from archives. */ 811 enum extract_rule extract_rule; 812 813 /* Sequence number of the last archive we used. */ 814 int last_archive_used; 815 816 /* If true print to stdout information about the files we are 817 trying to open. */ 818 bool trace_files; 819 820 /* If true multiple definitions are not considered an error; the 821 first is used. */ 822 bool muldefs; 823 824 /* If true undefined symbols when building DSOs are not fatal. */ 825 bool nodefs; 826 827 /* If true add line indentifying link-editor to .comment section. */ 828 bool add_ld_comment; 829 830 /* Stripping while linking. */ 831 enum 832 { 833 strip_none, 834 strip_debug, 835 strip_all, 836 strip_everything 837 } strip; 838 839 /* The callback function vector. */ 840 struct callbacks callbacks; 841 842 /* Name of the entry symbol. Can also be a numeric value. */ 843 const char *entry; 844 845 /* The description of the segments in the output file. */ 846 struct output_segment *output_segments; 847 848 /* List of the symbols we created from linker script definitions. */ 849 struct symbol *lscript_syms; 850 size_t nlscript_syms; 851 852 /* Table with known symbols. */ 853 ld_symbol_tab symbol_tab; 854 855 /* Table with used sections. */ 856 ld_section_tab section_tab; 857 858 /* The list of sections once we collected them. */ 859 struct scnhead **allsections; 860 size_t nallsections; 861 size_t nusedsections; 862 size_t nnotesections; 863 864 /* Beginning of the list of symbols which are still unresolved. */ 865 struct symbol *unresolved; 866 /* Number of truely unresolved entries in the list. */ 867 size_t nunresolved; 868 /* Number of truely unresolved, non-weak entries in the list. */ 869 size_t nunresolved_nonweak; 870 871 /* List of common symbols. */ 872 struct symbol *common_syms; 873 /* Section for the common symbols. */ 874 struct scninfo *common_section; 875 876 /* List of symbols defined in DSOs and used in a relocatable file. 877 DSO symbols not referenced in the relocatable files are not on 878 the list. If a symbol is on the list the on_dsolist field in the 879 'struct symbol' is nonzero. */ 880 struct symbol *from_dso; 881 /* Number of entries in from_dso. */ 882 size_t nfrom_dso; 883 /* Number of entries in the dynamic symbol table. */ 884 size_t ndynsym; 885 /* Number of PLT entries from DSO references. */ 886 size_t nplt; 887 /* Number of PLT entries from DSO references. */ 888 size_t ngot; 889 /* Number of copy relocations. */ 890 size_t ncopy; 891 /* Section for copy relocations. */ 892 struct scninfo *copy_section; 893 894 /* Keeping track of the number of symbols in the output file. */ 895 size_t nsymtab; 896 size_t nlocalsymbols; 897 898 /* Special symbols. */ 899 struct symbol *init_symbol; 900 struct symbol *fini_symbol; 901 902 /* The description of the segments in the output file as described 903 in the default linker script. This information will be used in 904 addition to the user-provided information. */ 905 struct output_segment *default_output_segments; 906 /* Search paths added by the default linker script. */ 907 struct pathelement *default_paths; 908 909 #ifndef BASE_ELF_NAME 910 /* The handle of the ld backend library. */ 911 void *ldlib; 912 #endif 913 914 /* String table for the section headers. */ 915 struct Ebl_Strtab *shstrtab; 916 917 /* True if output file should contain symbol table. */ 918 bool need_symtab; 919 /* Symbol table section. */ 920 Elf32_Word symscnidx; 921 /* Extended section table section. */ 922 Elf32_Word xndxscnidx; 923 /* Symbol string table section. */ 924 Elf32_Word strscnidx; 925 926 /* True if output file should contain dynamic symbol table. */ 927 bool need_dynsym; 928 /* Dynamic symbol table section. */ 929 Elf32_Word dynsymscnidx; 930 /* Dynamic symbol string table section. */ 931 Elf32_Word dynstrscnidx; 932 /* Dynamic symbol hash tables. */ 933 size_t hashscnidx; 934 size_t gnuhashscnidx; 935 936 /* Procedure linkage table section. */ 937 Elf32_Word pltscnidx; 938 /* Number of entries already in the PLT section. */ 939 size_t nplt_used; 940 /* Relocation for procedure linkage table section. */ 941 Elf32_Word pltrelscnidx; 942 943 /* Global offset table section. */ 944 Elf32_Word gotscnidx; 945 /* And the part of the PLT. */ 946 Elf32_Word gotpltscnidx; 947 948 /* This section will hole all non-PLT relocations. */ 949 Elf32_Word reldynscnidx; 950 951 /* Index of the sections to handle versioning. */ 952 Elf32_Word versymscnidx; 953 Elf32_Word verneedscnidx; 954 /* XXX Should the following names be verneed...? */ 955 /* Number of version definitions in input DSOs used. */ 956 int nverdefused; 957 /* Number of input DSOs using versioning. */ 958 int nverdeffile; 959 /* Index of next version. */ 960 int nextveridx; 961 962 /* TLS segment. */ 963 bool need_tls; 964 XElf_Addr tls_start; 965 XElf_Addr tls_tcb; 966 967 /* Hash table for version symbol strings. Only strings without 968 special characters are hashed here. */ 969 ld_version_str_tab version_str_tab; 970 /* At most one of the following two variables is set to true if either 971 global or local symbol binding is selected as the default. */ 972 bool default_bind_local; 973 bool default_bind_global; 974 975 /* Execuatable stack selection. */ 976 enum execstack 977 { 978 execstack_false = 0, 979 execstack_true, 980 execstack_false_force 981 } execstack; 982 983 /* True if only used sections are used. */ 984 bool gc_sections; 985 986 /* Array to determine final index of symbol. */ 987 Elf32_Word *dblindirect; 988 989 /* Section group handling. */ 990 struct scngroup 991 { 992 Elf32_Word outscnidx; 993 int nscns; 994 struct member 995 { 996 struct scnhead *scn; 997 struct member *next; 998 } *member; 999 struct Ebl_Strent *nameent; 1000 struct symbol *symbol; 1001 struct scngroup *next; 1002 } *groups; 1003 1004 /* True if the output file needs a .got section. */ 1005 bool need_got; 1006 /* Number of relocations for GOT section caused. */ 1007 size_t nrel_got; 1008 1009 /* Number of entries needed in the .dynamic section. */ 1010 int ndynamic; 1011 /* To keep track of added entries. */ 1012 int ndynamic_filled; 1013 /* Index for the dynamic section. */ 1014 Elf32_Word dynamicscnidx; 1015 1016 /* Flags set in the DT_FLAGS word. */ 1017 Elf32_Word dt_flags; 1018 /* Flags set in the DT_FLAGS_1 word. */ 1019 Elf32_Word dt_flags_1; 1020 /* Flags set in the DT_FEATURE_1 word. */ 1021 Elf32_Word dt_feature_1; 1022 1023 /* Lazy-loading state for dependencies. */ 1024 bool lazyload; 1025 1026 /* True if an .eh_frame_hdr section should be generated. */ 1027 bool eh_frame_hdr; 1028 1029 /* What hash style to generate. */ 1030 enum 1031 { 1032 hash_style_none = 0, 1033 hash_style_sysv = 1, 1034 #define GENERATE_SYSV_HASH ((ld_state.hash_style & hash_style_sysv) != 0) 1035 hash_style_gnu = 2 1036 #define GENERATE_GNU_HASH ((ld_state.hash_style & hash_style_gnu) != 0) 1037 } 1038 hash_style; 1039 1040 1041 /* True if in executables all global symbols should be exported in 1042 the dynamic symbol table. */ 1043 bool export_all_dynamic; 1044 1045 /* Build-ID style. NULL is none. */ 1046 const char *build_id; 1047 Elf32_Word buildidscnidx; 1048 1049 /* If DSO is generated, this is the SONAME. */ 1050 const char *soname; 1051 1052 /* List of all relocation sections. */ 1053 struct scninfo *rellist; 1054 /* Total size of non-PLT relocations. */ 1055 size_t relsize_total; 1056 1057 /* Record for the GOT symbol, if known. */ 1058 struct symbol *got_symbol; 1059 /* Record for the dynamic section symbol, if known. */ 1060 struct symbol *dyn_symbol; 1061 1062 /* Obstack used for small objects which will not be deleted. */ 1063 struct obstack smem; 1064 }; 1065 1066 1067 /* The interface to the scanner. */ 1068 1069 /* Parser entry point. */ 1070 extern int ldparse (void); 1071 1072 /* The input file. */ 1073 extern FILE *ldin; 1074 1075 /* Name of the input file. */ 1076 extern const char *ldin_fname; 1077 1078 /* Current line number. Must be reset for a new file. */ 1079 extern int ldlineno; 1080 1081 /* If nonzero we are currently parsing a version script. */ 1082 extern int ld_scan_version_script; 1083 1084 /* Flags defined in ld.c. */ 1085 extern int verbose; 1086 extern int conserve_memory; 1087 1088 1089 /* Linker state. This contains all global information. */ 1090 extern struct ld_state ld_state; 1091 1092 1093 /* Generic ld helper functions. */ 1094 1095 /* Append a new directory to search libraries in. */ 1096 extern void ld_new_searchdir (const char *dir); 1097 1098 /* Append a new file to the list of input files. */ 1099 extern struct usedfiles *ld_new_inputfile (const char *fname, 1100 enum file_type type); 1101 1102 1103 /* These are the generic implementations for the callbacks used by ld. */ 1104 1105 /* Initialize state object. This callback function is called after the 1106 parameters are parsed but before any file is searched for. */ 1107 extern int ld_prepare_state (const char *emulation); 1108 1109 1110 /* Function to determine whether an object will be dynamically linked. */ 1111 extern bool dynamically_linked_p (void); 1112 1113 /* Helper functions for the architecture specific code. */ 1114 1115 /* Checked whether the symbol is undefined and referenced from a DSO. */ 1116 extern bool linked_from_dso_p (struct scninfo *scninfo, size_t symidx); 1117 #ifdef __GNUC_STDC_INLINE__ 1118 __attribute__ ((__gnu_inline__)) 1119 #endif 1120 extern inline bool 1121 linked_from_dso_p (struct scninfo *scninfo, size_t symidx) 1122 { 1123 struct usedfiles *file = scninfo->fileinfo; 1124 1125 /* If this symbol is not undefined in this file it cannot come from 1126 a DSO. */ 1127 if (symidx < file->nlocalsymbols) 1128 return false; 1129 1130 struct symbol *sym = file->symref[symidx]; 1131 1132 return sym->defined && sym->in_dso; 1133 } 1134 1135 #endif /* ld.h */ 1136
