| /* ELF linking support for BFD. |
| Copyright 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 |
| Free Software Foundation, Inc. |
| |
| This file is part of BFD, the Binary File Descriptor library. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| |
| #include "bfd.h" |
| #include "sysdep.h" |
| #include "bfdlink.h" |
| #include "libbfd.h" |
| #define ARCH_SIZE 0 |
| #include "elf-bfd.h" |
| |
| bfd_boolean |
| _bfd_elf_create_got_section (abfd, info) |
| bfd *abfd; |
| struct bfd_link_info *info; |
| { |
| flagword flags; |
| asection *s; |
| struct elf_link_hash_entry *h; |
| struct bfd_link_hash_entry *bh; |
| struct elf_backend_data *bed = get_elf_backend_data (abfd); |
| int ptralign; |
| |
| /* This function may be called more than once. */ |
| s = bfd_get_section_by_name (abfd, ".got"); |
| if (s != NULL && (s->flags & SEC_LINKER_CREATED) != 0) |
| return TRUE; |
| |
| switch (bed->s->arch_size) |
| { |
| case 32: |
| ptralign = 2; |
| break; |
| |
| case 64: |
| ptralign = 3; |
| break; |
| |
| default: |
| bfd_set_error (bfd_error_bad_value); |
| return FALSE; |
| } |
| |
| flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY |
| | SEC_LINKER_CREATED); |
| |
| s = bfd_make_section (abfd, ".got"); |
| if (s == NULL |
| || !bfd_set_section_flags (abfd, s, flags) |
| || !bfd_set_section_alignment (abfd, s, ptralign)) |
| return FALSE; |
| |
| if (bed->want_got_plt) |
| { |
| s = bfd_make_section (abfd, ".got.plt"); |
| if (s == NULL |
| || !bfd_set_section_flags (abfd, s, flags) |
| || !bfd_set_section_alignment (abfd, s, ptralign)) |
| return FALSE; |
| } |
| |
| if (bed->want_got_sym) |
| { |
| /* Define the symbol _GLOBAL_OFFSET_TABLE_ at the start of the .got |
| (or .got.plt) section. We don't do this in the linker script |
| because we don't want to define the symbol if we are not creating |
| a global offset table. */ |
| bh = NULL; |
| if (!(_bfd_generic_link_add_one_symbol |
| (info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s, |
| bed->got_symbol_offset, (const char *) NULL, FALSE, |
| bed->collect, &bh))) |
| return FALSE; |
| h = (struct elf_link_hash_entry *) bh; |
| h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; |
| h->type = STT_OBJECT; |
| |
| if (info->shared |
| && ! _bfd_elf_link_record_dynamic_symbol (info, h)) |
| return FALSE; |
| |
| elf_hash_table (info)->hgot = h; |
| } |
| |
| /* The first bit of the global offset table is the header. */ |
| s->_raw_size += bed->got_header_size + bed->got_symbol_offset; |
| |
| return TRUE; |
| } |
| |
| /* Create dynamic sections when linking against a dynamic object. */ |
| |
| bfd_boolean |
| _bfd_elf_create_dynamic_sections (abfd, info) |
| bfd *abfd; |
| struct bfd_link_info *info; |
| { |
| flagword flags, pltflags; |
| asection *s; |
| struct elf_backend_data *bed = get_elf_backend_data (abfd); |
| int ptralign; |
| |
| switch (bed->s->arch_size) |
| { |
| case 32: |
| ptralign = 2; |
| break; |
| |
| case 64: |
| ptralign = 3; |
| break; |
| |
| default: |
| bfd_set_error (bfd_error_bad_value); |
| return FALSE; |
| } |
| |
| /* We need to create .plt, .rel[a].plt, .got, .got.plt, .dynbss, and |
| .rel[a].bss sections. */ |
| |
| flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY |
| | SEC_LINKER_CREATED); |
| |
| pltflags = flags; |
| pltflags |= SEC_CODE; |
| if (bed->plt_not_loaded) |
| pltflags &= ~ (SEC_CODE | SEC_LOAD | SEC_HAS_CONTENTS); |
| if (bed->plt_readonly) |
| pltflags |= SEC_READONLY; |
| |
| s = bfd_make_section (abfd, ".plt"); |
| if (s == NULL |
| || ! bfd_set_section_flags (abfd, s, pltflags) |
| || ! bfd_set_section_alignment (abfd, s, bed->plt_alignment)) |
| return FALSE; |
| |
| if (bed->want_plt_sym) |
| { |
| /* Define the symbol _PROCEDURE_LINKAGE_TABLE_ at the start of the |
| .plt section. */ |
| struct elf_link_hash_entry *h; |
| struct bfd_link_hash_entry *bh = NULL; |
| |
| if (! (_bfd_generic_link_add_one_symbol |
| (info, abfd, "_PROCEDURE_LINKAGE_TABLE_", BSF_GLOBAL, s, |
| (bfd_vma) 0, (const char *) NULL, FALSE, |
| get_elf_backend_data (abfd)->collect, &bh))) |
| return FALSE; |
| h = (struct elf_link_hash_entry *) bh; |
| h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; |
| h->type = STT_OBJECT; |
| |
| if (info->shared |
| && ! _bfd_elf_link_record_dynamic_symbol (info, h)) |
| return FALSE; |
| } |
| |
| s = bfd_make_section (abfd, |
| bed->default_use_rela_p ? ".rela.plt" : ".rel.plt"); |
| if (s == NULL |
| || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) |
| || ! bfd_set_section_alignment (abfd, s, ptralign)) |
| return FALSE; |
| |
| if (! _bfd_elf_create_got_section (abfd, info)) |
| return FALSE; |
| |
| if (bed->want_dynbss) |
| { |
| /* The .dynbss section is a place to put symbols which are defined |
| by dynamic objects, are referenced by regular objects, and are |
| not functions. We must allocate space for them in the process |
| image and use a R_*_COPY reloc to tell the dynamic linker to |
| initialize them at run time. The linker script puts the .dynbss |
| section into the .bss section of the final image. */ |
| s = bfd_make_section (abfd, ".dynbss"); |
| if (s == NULL |
| || ! bfd_set_section_flags (abfd, s, SEC_ALLOC)) |
| return FALSE; |
| |
| /* The .rel[a].bss section holds copy relocs. This section is not |
| normally needed. We need to create it here, though, so that the |
| linker will map it to an output section. We can't just create it |
| only if we need it, because we will not know whether we need it |
| until we have seen all the input files, and the first time the |
| main linker code calls BFD after examining all the input files |
| (size_dynamic_sections) the input sections have already been |
| mapped to the output sections. If the section turns out not to |
| be needed, we can discard it later. We will never need this |
| section when generating a shared object, since they do not use |
| copy relocs. */ |
| if (! info->shared) |
| { |
| s = bfd_make_section (abfd, |
| (bed->default_use_rela_p |
| ? ".rela.bss" : ".rel.bss")); |
| if (s == NULL |
| || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) |
| || ! bfd_set_section_alignment (abfd, s, ptralign)) |
| return FALSE; |
| } |
| } |
| |
| return TRUE; |
| } |
| |
| /* Record a new dynamic symbol. We record the dynamic symbols as we |
| read the input files, since we need to have a list of all of them |
| before we can determine the final sizes of the output sections. |
| Note that we may actually call this function even though we are not |
| going to output any dynamic symbols; in some cases we know that a |
| symbol should be in the dynamic symbol table, but only if there is |
| one. */ |
| |
| bfd_boolean |
| _bfd_elf_link_record_dynamic_symbol (info, h) |
| struct bfd_link_info *info; |
| struct elf_link_hash_entry *h; |
| { |
| if (h->dynindx == -1) |
| { |
| struct elf_strtab_hash *dynstr; |
| char *p, *alc; |
| const char *name; |
| bfd_boolean copy; |
| bfd_size_type indx; |
| |
| /* XXX: The ABI draft says the linker must turn hidden and |
| internal symbols into STB_LOCAL symbols when producing the |
| DSO. However, if ld.so honors st_other in the dynamic table, |
| this would not be necessary. */ |
| switch (ELF_ST_VISIBILITY (h->other)) |
| { |
| case STV_INTERNAL: |
| case STV_HIDDEN: |
| if (h->root.type != bfd_link_hash_undefined |
| && h->root.type != bfd_link_hash_undefweak) |
| { |
| h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL; |
| return TRUE; |
| } |
| |
| default: |
| break; |
| } |
| |
| h->dynindx = elf_hash_table (info)->dynsymcount; |
| ++elf_hash_table (info)->dynsymcount; |
| |
| dynstr = elf_hash_table (info)->dynstr; |
| if (dynstr == NULL) |
| { |
| /* Create a strtab to hold the dynamic symbol names. */ |
| elf_hash_table (info)->dynstr = dynstr = _bfd_elf_strtab_init (); |
| if (dynstr == NULL) |
| return FALSE; |
| } |
| |
| /* We don't put any version information in the dynamic string |
| table. */ |
| name = h->root.root.string; |
| p = strchr (name, ELF_VER_CHR); |
| if (p == NULL) |
| { |
| alc = NULL; |
| copy = FALSE; |
| } |
| else |
| { |
| size_t len = p - name + 1; |
| |
| alc = bfd_malloc ((bfd_size_type) len); |
| if (alc == NULL) |
| return FALSE; |
| memcpy (alc, name, len - 1); |
| alc[len - 1] = '\0'; |
| name = alc; |
| copy = TRUE; |
| } |
| |
| indx = _bfd_elf_strtab_add (dynstr, name, copy); |
| |
| if (alc != NULL) |
| free (alc); |
| |
| if (indx == (bfd_size_type) -1) |
| return FALSE; |
| h->dynstr_index = indx; |
| } |
| |
| return TRUE; |
| } |
| |
| /* Record a new local dynamic symbol. Returns 0 on failure, 1 on |
| success, and 2 on a failure caused by attempting to record a symbol |
| in a discarded section, eg. a discarded link-once section symbol. */ |
| |
| int |
| elf_link_record_local_dynamic_symbol (info, input_bfd, input_indx) |
| struct bfd_link_info *info; |
| bfd *input_bfd; |
| long input_indx; |
| { |
| bfd_size_type amt; |
| struct elf_link_local_dynamic_entry *entry; |
| struct elf_link_hash_table *eht; |
| struct elf_strtab_hash *dynstr; |
| unsigned long dynstr_index; |
| char *name; |
| Elf_External_Sym_Shndx eshndx; |
| char esym[sizeof (Elf64_External_Sym)]; |
| |
| if (! is_elf_hash_table (info)) |
| return 0; |
| |
| /* See if the entry exists already. */ |
| for (entry = elf_hash_table (info)->dynlocal; entry ; entry = entry->next) |
| if (entry->input_bfd == input_bfd && entry->input_indx == input_indx) |
| return 1; |
| |
| amt = sizeof (*entry); |
| entry = (struct elf_link_local_dynamic_entry *) bfd_alloc (input_bfd, amt); |
| if (entry == NULL) |
| return 0; |
| |
| /* Go find the symbol, so that we can find it's name. */ |
| if (!bfd_elf_get_elf_syms (input_bfd, &elf_tdata (input_bfd)->symtab_hdr, |
| (size_t) 1, (size_t) input_indx, |
| &entry->isym, esym, &eshndx)) |
| { |
| bfd_release (input_bfd, entry); |
| return 0; |
| } |
| |
| if (entry->isym.st_shndx != SHN_UNDEF |
| && (entry->isym.st_shndx < SHN_LORESERVE |
| || entry->isym.st_shndx > SHN_HIRESERVE)) |
| { |
| asection *s; |
| |
| s = bfd_section_from_elf_index (input_bfd, entry->isym.st_shndx); |
| if (s == NULL || bfd_is_abs_section (s->output_section)) |
| { |
| /* We can still bfd_release here as nothing has done another |
| bfd_alloc. We can't do this later in this function. */ |
| bfd_release (input_bfd, entry); |
| return 2; |
| } |
| } |
| |
| name = (bfd_elf_string_from_elf_section |
| (input_bfd, elf_tdata (input_bfd)->symtab_hdr.sh_link, |
| entry->isym.st_name)); |
| |
| dynstr = elf_hash_table (info)->dynstr; |
| if (dynstr == NULL) |
| { |
| /* Create a strtab to hold the dynamic symbol names. */ |
| elf_hash_table (info)->dynstr = dynstr = _bfd_elf_strtab_init (); |
| if (dynstr == NULL) |
| return 0; |
| } |
| |
| dynstr_index = _bfd_elf_strtab_add (dynstr, name, FALSE); |
| if (dynstr_index == (unsigned long) -1) |
| return 0; |
| entry->isym.st_name = dynstr_index; |
| |
| eht = elf_hash_table (info); |
| |
| entry->next = eht->dynlocal; |
| eht->dynlocal = entry; |
| entry->input_bfd = input_bfd; |
| entry->input_indx = input_indx; |
| eht->dynsymcount++; |
| |
| /* Whatever binding the symbol had before, it's now local. */ |
| entry->isym.st_info |
| = ELF_ST_INFO (STB_LOCAL, ELF_ST_TYPE (entry->isym.st_info)); |
| |
| /* The dynindx will be set at the end of size_dynamic_sections. */ |
| |
| return 1; |
| } |
| |
| /* Return the dynindex of a local dynamic symbol. */ |
| |
| long |
| _bfd_elf_link_lookup_local_dynindx (info, input_bfd, input_indx) |
| struct bfd_link_info *info; |
| bfd *input_bfd; |
| long input_indx; |
| { |
| struct elf_link_local_dynamic_entry *e; |
| |
| for (e = elf_hash_table (info)->dynlocal; e ; e = e->next) |
| if (e->input_bfd == input_bfd && e->input_indx == input_indx) |
| return e->dynindx; |
| return -1; |
| } |
| |
| /* This function is used to renumber the dynamic symbols, if some of |
| them are removed because they are marked as local. This is called |
| via elf_link_hash_traverse. */ |
| |
| static bfd_boolean elf_link_renumber_hash_table_dynsyms |
| PARAMS ((struct elf_link_hash_entry *, PTR)); |
| |
| static bfd_boolean |
| elf_link_renumber_hash_table_dynsyms (h, data) |
| struct elf_link_hash_entry *h; |
| PTR data; |
| { |
| size_t *count = (size_t *) data; |
| |
| if (h->root.type == bfd_link_hash_warning) |
| h = (struct elf_link_hash_entry *) h->root.u.i.link; |
| |
| if (h->dynindx != -1) |
| h->dynindx = ++(*count); |
| |
| return TRUE; |
| } |
| |
| /* Assign dynsym indices. In a shared library we generate a section |
| symbol for each output section, which come first. Next come all of |
| the back-end allocated local dynamic syms, followed by the rest of |
| the global symbols. */ |
| |
| unsigned long |
| _bfd_elf_link_renumber_dynsyms (output_bfd, info) |
| bfd *output_bfd; |
| struct bfd_link_info *info; |
| { |
| unsigned long dynsymcount = 0; |
| |
| if (info->shared) |
| { |
| asection *p; |
| for (p = output_bfd->sections; p ; p = p->next) |
| if ((p->flags & SEC_EXCLUDE) == 0) |
| elf_section_data (p)->dynindx = ++dynsymcount; |
| } |
| |
| if (elf_hash_table (info)->dynlocal) |
| { |
| struct elf_link_local_dynamic_entry *p; |
| for (p = elf_hash_table (info)->dynlocal; p ; p = p->next) |
| p->dynindx = ++dynsymcount; |
| } |
| |
| elf_link_hash_traverse (elf_hash_table (info), |
| elf_link_renumber_hash_table_dynsyms, |
| &dynsymcount); |
| |
| /* There is an unused NULL entry at the head of the table which |
| we must account for in our count. Unless there weren't any |
| symbols, which means we'll have no table at all. */ |
| if (dynsymcount != 0) |
| ++dynsymcount; |
| |
| return elf_hash_table (info)->dynsymcount = dynsymcount; |
| } |
| |
| /* Create a special linker section, or return a pointer to a linker |
| section already created */ |
| |
| elf_linker_section_t * |
| _bfd_elf_create_linker_section (abfd, info, which, defaults) |
| bfd *abfd; |
| struct bfd_link_info *info; |
| enum elf_linker_section_enum which; |
| elf_linker_section_t *defaults; |
| { |
| bfd *dynobj = elf_hash_table (info)->dynobj; |
| elf_linker_section_t *lsect; |
| |
| /* Record the first bfd section that needs the special section */ |
| if (!dynobj) |
| dynobj = elf_hash_table (info)->dynobj = abfd; |
| |
| /* If this is the first time, create the section */ |
| lsect = elf_linker_section (dynobj, which); |
| if (!lsect) |
| { |
| asection *s; |
| bfd_size_type amt = sizeof (elf_linker_section_t); |
| |
| lsect = (elf_linker_section_t *) bfd_alloc (dynobj, amt); |
| |
| *lsect = *defaults; |
| elf_linker_section (dynobj, which) = lsect; |
| lsect->which = which; |
| lsect->hole_written_p = FALSE; |
| |
| /* See if the sections already exist */ |
| lsect->section = s = bfd_get_section_by_name (dynobj, lsect->name); |
| if (!s || (s->flags & defaults->flags) != defaults->flags) |
| { |
| lsect->section = s = bfd_make_section_anyway (dynobj, lsect->name); |
| |
| if (s == NULL) |
| return (elf_linker_section_t *)0; |
| |
| bfd_set_section_flags (dynobj, s, defaults->flags); |
| bfd_set_section_alignment (dynobj, s, lsect->alignment); |
| } |
| else if (bfd_get_section_alignment (dynobj, s) < lsect->alignment) |
| bfd_set_section_alignment (dynobj, s, lsect->alignment); |
| |
| s->_raw_size = align_power (s->_raw_size, lsect->alignment); |
| |
| /* Is there a hole we have to provide? If so check whether the |
| segment is too big already */ |
| if (lsect->hole_size) |
| { |
| lsect->hole_offset = s->_raw_size; |
| s->_raw_size += lsect->hole_size; |
| if (lsect->hole_offset > lsect->max_hole_offset) |
| { |
| (*_bfd_error_handler) |
| (_("%s: Section %s is too large to add hole of %ld bytes"), |
| bfd_get_filename (abfd), |
| lsect->name, |
| (long) lsect->hole_size); |
| |
| bfd_set_error (bfd_error_bad_value); |
| return (elf_linker_section_t *)0; |
| } |
| } |
| |
| #ifdef DEBUG |
| fprintf (stderr, "Creating section %s, current size = %ld\n", |
| lsect->name, (long)s->_raw_size); |
| #endif |
| |
| if (lsect->sym_name) |
| { |
| struct elf_link_hash_entry *h; |
| struct bfd_link_hash_entry *bh; |
| |
| #ifdef DEBUG |
| fprintf (stderr, "Adding %s to section %s\n", |
| lsect->sym_name, |
| lsect->name); |
| #endif |
| bh = bfd_link_hash_lookup (info->hash, lsect->sym_name, |
| FALSE, FALSE, FALSE); |
| |
| if ((bh == NULL || bh->type == bfd_link_hash_undefined) |
| && !(_bfd_generic_link_add_one_symbol |
| (info, abfd, lsect->sym_name, BSF_GLOBAL, s, |
| (lsect->hole_size |
| ? s->_raw_size - lsect->hole_size + lsect->sym_offset |
| : lsect->sym_offset), |
| (const char *) NULL, FALSE, |
| get_elf_backend_data (abfd)->collect, &bh))) |
| return (elf_linker_section_t *) 0; |
| h = (struct elf_link_hash_entry *) bh; |
| |
| if ((defaults->which != LINKER_SECTION_SDATA) |
| && (defaults->which != LINKER_SECTION_SDATA2)) |
| h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_DYNAMIC; |
| |
| h->type = STT_OBJECT; |
| lsect->sym_hash = h; |
| |
| if (info->shared |
| && ! _bfd_elf_link_record_dynamic_symbol (info, h)) |
| return (elf_linker_section_t *) 0; |
| } |
| } |
| |
| #if 0 |
| /* This does not make sense. The sections which may exist in the |
| object file have nothing to do with the sections we want to |
| create. */ |
| |
| /* Find the related sections if they have been created */ |
| if (lsect->bss_name && !lsect->bss_section) |
| lsect->bss_section = bfd_get_section_by_name (dynobj, lsect->bss_name); |
| |
| if (lsect->rel_name && !lsect->rel_section) |
| lsect->rel_section = bfd_get_section_by_name (dynobj, lsect->rel_name); |
| #endif |
| |
| return lsect; |
| } |
| |
| /* Find a linker generated pointer with a given addend and type. */ |
| |
| elf_linker_section_pointers_t * |
| _bfd_elf_find_pointer_linker_section (linker_pointers, addend, which) |
| elf_linker_section_pointers_t *linker_pointers; |
| bfd_vma addend; |
| elf_linker_section_enum_t which; |
| { |
| for ( ; linker_pointers != NULL; linker_pointers = linker_pointers->next) |
| { |
| if (which == linker_pointers->which && addend == linker_pointers->addend) |
| return linker_pointers; |
| } |
| |
| return (elf_linker_section_pointers_t *)0; |
| } |
| |
| /* Make the .rela section corresponding to the generated linker section. */ |
| |
| bfd_boolean |
| _bfd_elf_make_linker_section_rela (dynobj, lsect, alignment) |
| bfd *dynobj; |
| elf_linker_section_t *lsect; |
| int alignment; |
| { |
| if (lsect->rel_section) |
| return TRUE; |
| |
| lsect->rel_section = bfd_get_section_by_name (dynobj, lsect->rel_name); |
| if (lsect->rel_section == NULL) |
| { |
| lsect->rel_section = bfd_make_section (dynobj, lsect->rel_name); |
| if (lsect->rel_section == NULL |
| || ! bfd_set_section_flags (dynobj, |
| lsect->rel_section, |
| (SEC_ALLOC |
| | SEC_LOAD |
| | SEC_HAS_CONTENTS |
| | SEC_IN_MEMORY |
| | SEC_LINKER_CREATED |
| | SEC_READONLY)) |
| || ! bfd_set_section_alignment (dynobj, lsect->rel_section, alignment)) |
| return FALSE; |
| } |
| |
| return TRUE; |
| } |