413 lines
12 KiB
C
413 lines
12 KiB
C
/* ELF linking support for BFD.
|
||
Copyright 1995, 1996, 1997 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);
|
||
|
||
/* This function may be called more than once. */
|
||
if (bfd_get_section_by_name (abfd, ".got") != NULL)
|
||
return true;
|
||
|
||
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, 2))
|
||
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, 2))
|
||
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, (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;
|
||
|
||
elf_hash_table (info)->hgot = h;
|
||
|
||
/* The first three global offset table entries are reserved. */
|
||
s->_raw_size += 3 * 4;
|
||
|
||
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;
|
||
register asection *s;
|
||
struct elf_backend_data *bed = get_elf_backend_data (abfd);
|
||
|
||
/* 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);
|
||
|
||
s = bfd_make_section (abfd, ".plt");
|
||
if (s == NULL
|
||
|| ! bfd_set_section_flags (abfd, s,
|
||
(flags | SEC_CODE
|
||
| (bed->plt_readonly ? SEC_READONLY : 0)))
|
||
|| ! bfd_set_section_alignment (abfd, s, 2))
|
||
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->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, 2))
|
||
return false;
|
||
|
||
if (! _bfd_elf_create_got_section (abfd, info))
|
||
return false;
|
||
|
||
/* 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->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, 2))
|
||
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;
|
||
|
||
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;
|
||
}
|
||
|
||
/* 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;
|
||
}
|