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/* ELF linking support for BFD.

   Copyright 1995, 96, 97, 98, 99, 2000 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"

boolean

_bfd_elf_create_got_section (abfd, info)

     bfd *abfd;

     struct bfd_link_info *info;

{

  flagword flags;

  register asection *s;

  struct elf_link_hash_entry *h;

  struct elf_backend_data *bed = get_elf_backend_data (abfd);

  int ptralign;

  /* This function may be called more than once.  */

  if (bfd_get_section_by_name (abfd, ".got") != NULL)

    return true;

  switch (bed->s->arch_size)

    {

    case 32: ptralign = 2; break;

    case 64: ptralign = 3; break;

    default: abort();

    }

  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;

    }

  /* 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.  */

  h = 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, (struct bfd_link_hash_entry **) &h)))

    return false;

  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.  */

boolean

_bfd_elf_create_dynamic_sections (abfd, info)

     bfd *abfd;

     struct bfd_link_info *info;

{

  flagword flags, pltflags;

  register asection *s;

  struct elf_backend_data *bed = get_elf_backend_data (abfd);

  int ptralign = 0;

  switch (bed->s->arch_size)

    {

    case 32: ptralign = 2; break;

    case 64: ptralign = 3; break;

    default: abort();

    }

  /* 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_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 = 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,

              (struct bfd_link_hash_entry **) &h)))

        return false;

      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.  */

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 bfd_strtab_hash *dynstr;

      char *p, *alc;

      const char *name;

      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:

          /* This symbol must be defined in the shared object or

             executable.  */

          if (h->root.type == bfd_link_hash_undefined)

            {

              bfd * abfd = h->root.u.undef.abfd;

              const char * name = h->root.root.string;

              (*info->callbacks->undefined_symbol)

                (info, name, abfd, bfd_und_section_ptr, 0, true);

            }

          h->elf_link_hash_flags |= ELF_LINK_FORCED_LOCAL;

          break;

        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_stringtab_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

        {

          alc = bfd_malloc (p - name + 1);

          if (alc == NULL)

            return false;

          strncpy (alc, name, p - name);

          alc[p - name] = '\0';

          name = alc;

          copy = true;

        }

      indx = _bfd_stringtab_add (dynstr, name, true, copy);

      if (alc != NULL)

        free (alc);

      if (indx == (bfd_size_type) -1)

        return false;

      h->dynstr_index = indx;

    }

  return true;

}

/* 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 boolean elf_link_renumber_hash_table_dynsyms

  PARAMS ((struct elf_link_hash_entry *, PTR));

static 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->dynindx != -1)

    h->dynindx = ++(*count);

  return true;

}

/* Assign dynsym indicies.  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)

        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;

      lsect = (elf_linker_section_t *)

        bfd_alloc (dynobj, sizeof (elf_linker_section_t));

      *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 already to large to put hole of %ld bytes in"),

                                     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 = NULL;

#ifdef DEBUG

          fprintf (stderr, "Adding %s to section %s\n",

                   lsect->sym_name,

                   lsect->name);

#endif

          h = (struct elf_link_hash_entry *)

            bfd_link_hash_lookup (info->hash, lsect->sym_name, false, false, false);

          if ((h == NULL || h->root.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,

                                                     (struct bfd_link_hash_entry **) &h)))

            return (elf_linker_section_t *)0;

          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_signed_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.  */

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;

}