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elf.c
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elf.c
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/* ELF executable support for BFD.
Copyright (C) 1993-2024 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 3 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., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
/*
SECTION
ELF backends
BFD support for ELF formats is being worked on.
Currently, the best supported back ends are for sparc and i386
(running svr4 or Solaris 2).
Documentation of the internals of the support code still needs
to be written. The code is changing quickly enough that we
haven't bothered yet. */
/* For sparc64-cross-sparc32. */
#define _SYSCALL32
#include "sysdep.h"
#include <limits.h>
#include "bfd.h"
#include "bfdlink.h"
#include "libbfd.h"
#define ARCH_SIZE 0
#include "elf-bfd.h"
#include "libiberty.h"
#include "safe-ctype.h"
#include "elf-linux-core.h"
#ifdef CORE_HEADER
#include CORE_HEADER
#endif
static int elf_sort_sections (const void *, const void *);
static bool assign_file_positions_except_relocs (bfd *, struct bfd_link_info *);
static bool swap_out_syms (bfd *, struct elf_strtab_hash **, int,
struct bfd_link_info *);
static bool elf_parse_notes (bfd *abfd, char *buf, size_t size,
file_ptr offset, size_t align);
/* Swap version information in and out. The version information is
currently size independent. If that ever changes, this code will
need to move into elfcode.h. */
/* Swap in a Verdef structure. */
void
_bfd_elf_swap_verdef_in (bfd *abfd,
const Elf_External_Verdef *src,
Elf_Internal_Verdef *dst)
{
dst->vd_version = H_GET_16 (abfd, src->vd_version);
dst->vd_flags = H_GET_16 (abfd, src->vd_flags);
dst->vd_ndx = H_GET_16 (abfd, src->vd_ndx);
dst->vd_cnt = H_GET_16 (abfd, src->vd_cnt);
dst->vd_hash = H_GET_32 (abfd, src->vd_hash);
dst->vd_aux = H_GET_32 (abfd, src->vd_aux);
dst->vd_next = H_GET_32 (abfd, src->vd_next);
}
/* Swap out a Verdef structure. */
void
_bfd_elf_swap_verdef_out (bfd *abfd,
const Elf_Internal_Verdef *src,
Elf_External_Verdef *dst)
{
H_PUT_16 (abfd, src->vd_version, dst->vd_version);
H_PUT_16 (abfd, src->vd_flags, dst->vd_flags);
H_PUT_16 (abfd, src->vd_ndx, dst->vd_ndx);
H_PUT_16 (abfd, src->vd_cnt, dst->vd_cnt);
H_PUT_32 (abfd, src->vd_hash, dst->vd_hash);
H_PUT_32 (abfd, src->vd_aux, dst->vd_aux);
H_PUT_32 (abfd, src->vd_next, dst->vd_next);
}
/* Swap in a Verdaux structure. */
void
_bfd_elf_swap_verdaux_in (bfd *abfd,
const Elf_External_Verdaux *src,
Elf_Internal_Verdaux *dst)
{
dst->vda_name = H_GET_32 (abfd, src->vda_name);
dst->vda_next = H_GET_32 (abfd, src->vda_next);
}
/* Swap out a Verdaux structure. */
void
_bfd_elf_swap_verdaux_out (bfd *abfd,
const Elf_Internal_Verdaux *src,
Elf_External_Verdaux *dst)
{
H_PUT_32 (abfd, src->vda_name, dst->vda_name);
H_PUT_32 (abfd, src->vda_next, dst->vda_next);
}
/* Swap in a Verneed structure. */
void
_bfd_elf_swap_verneed_in (bfd *abfd,
const Elf_External_Verneed *src,
Elf_Internal_Verneed *dst)
{
dst->vn_version = H_GET_16 (abfd, src->vn_version);
dst->vn_cnt = H_GET_16 (abfd, src->vn_cnt);
dst->vn_file = H_GET_32 (abfd, src->vn_file);
dst->vn_aux = H_GET_32 (abfd, src->vn_aux);
dst->vn_next = H_GET_32 (abfd, src->vn_next);
}
/* Swap out a Verneed structure. */
void
_bfd_elf_swap_verneed_out (bfd *abfd,
const Elf_Internal_Verneed *src,
Elf_External_Verneed *dst)
{
H_PUT_16 (abfd, src->vn_version, dst->vn_version);
H_PUT_16 (abfd, src->vn_cnt, dst->vn_cnt);
H_PUT_32 (abfd, src->vn_file, dst->vn_file);
H_PUT_32 (abfd, src->vn_aux, dst->vn_aux);
H_PUT_32 (abfd, src->vn_next, dst->vn_next);
}
/* Swap in a Vernaux structure. */
void
_bfd_elf_swap_vernaux_in (bfd *abfd,
const Elf_External_Vernaux *src,
Elf_Internal_Vernaux *dst)
{
dst->vna_hash = H_GET_32 (abfd, src->vna_hash);
dst->vna_flags = H_GET_16 (abfd, src->vna_flags);
dst->vna_other = H_GET_16 (abfd, src->vna_other);
dst->vna_name = H_GET_32 (abfd, src->vna_name);
dst->vna_next = H_GET_32 (abfd, src->vna_next);
}
/* Swap out a Vernaux structure. */
void
_bfd_elf_swap_vernaux_out (bfd *abfd,
const Elf_Internal_Vernaux *src,
Elf_External_Vernaux *dst)
{
H_PUT_32 (abfd, src->vna_hash, dst->vna_hash);
H_PUT_16 (abfd, src->vna_flags, dst->vna_flags);
H_PUT_16 (abfd, src->vna_other, dst->vna_other);
H_PUT_32 (abfd, src->vna_name, dst->vna_name);
H_PUT_32 (abfd, src->vna_next, dst->vna_next);
}
/* Swap in a Versym structure. */
void
_bfd_elf_swap_versym_in (bfd *abfd,
const Elf_External_Versym *src,
Elf_Internal_Versym *dst)
{
dst->vs_vers = H_GET_16 (abfd, src->vs_vers);
}
/* Swap out a Versym structure. */
void
_bfd_elf_swap_versym_out (bfd *abfd,
const Elf_Internal_Versym *src,
Elf_External_Versym *dst)
{
H_PUT_16 (abfd, src->vs_vers, dst->vs_vers);
}
/* Standard ELF hash function. Do not change this function; you will
cause invalid hash tables to be generated. */
unsigned long
bfd_elf_hash (const char *namearg)
{
uint32_t h = 0;
for (const unsigned char *name = (const unsigned char *) namearg;
*name; name++)
{
h = (h << 4) + *name;
h ^= (h >> 24) & 0xf0;
}
return h & 0x0fffffff;
}
/* DT_GNU_HASH hash function. Do not change this function; you will
cause invalid hash tables to be generated. */
unsigned long
bfd_elf_gnu_hash (const char *namearg)
{
uint32_t h = 5381;
for (const unsigned char *name = (const unsigned char *) namearg;
*name; name++)
h = (h << 5) + h + *name;
return h;
}
/* Create a tdata field OBJECT_SIZE bytes in length, zeroed out and with
the object_id field of an elf_obj_tdata field set to OBJECT_ID. */
bool
bfd_elf_allocate_object (bfd *abfd,
size_t object_size,
enum elf_target_id object_id)
{
BFD_ASSERT (object_size >= sizeof (struct elf_obj_tdata));
abfd->tdata.any = bfd_zalloc (abfd, object_size);
if (abfd->tdata.any == NULL)
return false;
elf_object_id (abfd) = object_id;
if (abfd->direction != read_direction)
{
struct output_elf_obj_tdata *o = bfd_zalloc (abfd, sizeof *o);
if (o == NULL)
return false;
elf_tdata (abfd)->o = o;
elf_program_header_size (abfd) = (bfd_size_type) -1;
}
return true;
}
bool
bfd_elf_make_object (bfd *abfd)
{
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
return bfd_elf_allocate_object (abfd, sizeof (struct elf_obj_tdata),
bed->target_id);
}
bool
bfd_elf_mkcorefile (bfd *abfd)
{
/* I think this can be done just like an object file. */
if (!abfd->xvec->_bfd_set_format[(int) bfd_object] (abfd))
return false;
elf_tdata (abfd)->core = bfd_zalloc (abfd, sizeof (*elf_tdata (abfd)->core));
return elf_tdata (abfd)->core != NULL;
}
char *
bfd_elf_get_str_section (bfd *abfd, unsigned int shindex)
{
Elf_Internal_Shdr **i_shdrp;
bfd_byte *shstrtab = NULL;
file_ptr offset;
bfd_size_type shstrtabsize;
i_shdrp = elf_elfsections (abfd);
if (i_shdrp == 0
|| shindex >= elf_numsections (abfd)
|| i_shdrp[shindex] == 0)
return NULL;
shstrtab = i_shdrp[shindex]->contents;
if (shstrtab == NULL)
{
/* No cached one, attempt to read, and cache what we read. */
offset = i_shdrp[shindex]->sh_offset;
shstrtabsize = i_shdrp[shindex]->sh_size;
if (shstrtabsize == 0
|| bfd_seek (abfd, offset, SEEK_SET) != 0
|| (shstrtab = _bfd_mmap_persistent (abfd, shstrtabsize)) == NULL)
{
/* Once we've failed to read it, make sure we don't keep
trying. Otherwise, we'll keep allocating space for
the string table over and over. */
i_shdrp[shindex]->sh_size = 0;
}
else if (shstrtab[shstrtabsize - 1] != 0)
{
/* It is an error if a string table isn't terminated. */
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: string table [%u] is corrupt"), abfd, shindex);
shstrtab[shstrtabsize - 1] = 0;
}
i_shdrp[shindex]->contents = shstrtab;
}
return (char *) shstrtab;
}
char *
bfd_elf_string_from_elf_section (bfd *abfd,
unsigned int shindex,
unsigned int strindex)
{
Elf_Internal_Shdr *hdr;
if (strindex == 0)
return "";
if (elf_elfsections (abfd) == NULL || shindex >= elf_numsections (abfd))
return NULL;
hdr = elf_elfsections (abfd)[shindex];
if (hdr->contents == NULL)
{
if (hdr->sh_type != SHT_STRTAB && hdr->sh_type < SHT_LOOS)
{
/* PR 17512: file: f057ec89. */
/* xgettext:c-format */
_bfd_error_handler (_("%pB: attempt to load strings from"
" a non-string section (number %d)"),
abfd, shindex);
return NULL;
}
if (bfd_elf_get_str_section (abfd, shindex) == NULL)
return NULL;
}
else
{
/* PR 24273: The string section's contents may have already
been loaded elsewhere, eg because a corrupt file has the
string section index in the ELF header pointing at a group
section. So be paranoid, and test that the last byte of
the section is zero. */
if (hdr->sh_size == 0 || hdr->contents[hdr->sh_size - 1] != 0)
return NULL;
}
if (strindex >= hdr->sh_size)
{
unsigned int shstrndx = elf_elfheader(abfd)->e_shstrndx;
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: invalid string offset %u >= %" PRIu64 " for section `%s'"),
abfd, strindex, (uint64_t) hdr->sh_size,
(shindex == shstrndx && strindex == hdr->sh_name
? ".shstrtab"
: bfd_elf_string_from_elf_section (abfd, shstrndx, hdr->sh_name)));
return NULL;
}
return ((char *) hdr->contents) + strindex;
}
/* Read and convert symbols to internal format.
SYMCOUNT specifies the number of symbols to read, starting from
symbol SYMOFFSET. If any of INTSYM_BUF, EXTSYM_BUF or EXTSHNDX_BUF
are non-NULL, they are used to store the internal symbols, external
symbols, and symbol section index extensions, respectively.
Returns a pointer to the internal symbol buffer (malloced if necessary)
or NULL if there were no symbols or some kind of problem. */
Elf_Internal_Sym *
bfd_elf_get_elf_syms (bfd *ibfd,
Elf_Internal_Shdr *symtab_hdr,
size_t symcount,
size_t symoffset,
Elf_Internal_Sym *intsym_buf,
void *extsym_buf,
Elf_External_Sym_Shndx *extshndx_buf)
{
Elf_Internal_Shdr *shndx_hdr;
void *alloc_ext;
const bfd_byte *esym;
Elf_External_Sym_Shndx *alloc_extshndx;
Elf_External_Sym_Shndx *shndx;
Elf_Internal_Sym *alloc_intsym;
Elf_Internal_Sym *isym;
Elf_Internal_Sym *isymend;
const struct elf_backend_data *bed;
size_t extsym_size;
size_t amt;
file_ptr pos;
if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour)
abort ();
if (symcount == 0)
return intsym_buf;
if (elf_use_dt_symtab_p (ibfd))
{
/* Use dynamic symbol table. */
if (elf_tdata (ibfd)->dt_symtab_count != symcount + symoffset)
{
bfd_set_error (bfd_error_invalid_operation);
return NULL;
}
return elf_tdata (ibfd)->dt_symtab + symoffset;
}
/* Normal syms might have section extension entries. */
shndx_hdr = NULL;
if (elf_symtab_shndx_list (ibfd) != NULL)
{
elf_section_list * entry;
Elf_Internal_Shdr **sections = elf_elfsections (ibfd);
/* Find an index section that is linked to this symtab section. */
for (entry = elf_symtab_shndx_list (ibfd); entry != NULL; entry = entry->next)
{
/* PR 20063. */
if (entry->hdr.sh_link >= elf_numsections (ibfd))
continue;
if (sections[entry->hdr.sh_link] == symtab_hdr)
{
shndx_hdr = & entry->hdr;
break;
};
}
if (shndx_hdr == NULL)
{
if (symtab_hdr == &elf_symtab_hdr (ibfd))
/* Not really accurate, but this was how the old code used
to work. */
shndx_hdr = &elf_symtab_shndx_list (ibfd)->hdr;
/* Otherwise we do nothing. The assumption is that
the index table will not be needed. */
}
}
/* Read the symbols. */
alloc_ext = NULL;
alloc_extshndx = NULL;
alloc_intsym = NULL;
bed = get_elf_backend_data (ibfd);
extsym_size = bed->s->sizeof_sym;
if (_bfd_mul_overflow (symcount, extsym_size, &amt))
{
bfd_set_error (bfd_error_file_too_big);
return NULL;
}
pos = symtab_hdr->sh_offset + symoffset * extsym_size;
size_t alloc_ext_size = amt;
if (bfd_seek (ibfd, pos, SEEK_SET) != 0
|| !_bfd_mmap_read_temporary (&extsym_buf, &alloc_ext_size,
&alloc_ext, ibfd, false))
{
intsym_buf = NULL;
goto out2;
}
size_t alloc_extshndx_size = 0;
if (shndx_hdr == NULL || shndx_hdr->sh_size == 0)
extshndx_buf = NULL;
else
{
if (_bfd_mul_overflow (symcount, sizeof (Elf_External_Sym_Shndx), &amt))
{
bfd_set_error (bfd_error_file_too_big);
intsym_buf = NULL;
goto out1;
}
alloc_extshndx_size = amt;
pos = shndx_hdr->sh_offset + symoffset * sizeof (Elf_External_Sym_Shndx);
if (bfd_seek (ibfd, pos, SEEK_SET) != 0
|| !_bfd_mmap_read_temporary ((void **) &extshndx_buf,
&alloc_extshndx_size,
(void **) &alloc_extshndx,
ibfd, false))
{
intsym_buf = NULL;
goto out1;
}
}
if (intsym_buf == NULL)
{
if (_bfd_mul_overflow (symcount, sizeof (Elf_Internal_Sym), &amt))
{
bfd_set_error (bfd_error_file_too_big);
goto out1;
}
alloc_intsym = (Elf_Internal_Sym *) bfd_malloc (amt);
intsym_buf = alloc_intsym;
if (intsym_buf == NULL)
goto out1;
}
/* Convert the symbols to internal form. */
isymend = intsym_buf + symcount;
for (esym = (const bfd_byte *) extsym_buf, isym = intsym_buf,
shndx = extshndx_buf;
isym < isymend;
esym += extsym_size, isym++, shndx = shndx != NULL ? shndx + 1 : NULL)
if (!(*bed->s->swap_symbol_in) (ibfd, esym, shndx, isym))
{
symoffset += (esym - (bfd_byte *) extsym_buf) / extsym_size;
/* xgettext:c-format */
_bfd_error_handler (_("%pB symbol number %lu references"
" nonexistent SHT_SYMTAB_SHNDX section"),
ibfd, (unsigned long) symoffset);
free (alloc_intsym);
intsym_buf = NULL;
goto out1;
}
out1:
_bfd_munmap_temporary (alloc_extshndx, alloc_extshndx_size);
out2:
_bfd_munmap_temporary (alloc_ext, alloc_ext_size);
return intsym_buf;
}
/* Look up a symbol name. */
static const char *
bfd_elf_sym_name_raw (bfd *abfd,
Elf_Internal_Shdr *symtab_hdr,
Elf_Internal_Sym *isym)
{
unsigned int iname = isym->st_name;
unsigned int shindex = symtab_hdr->sh_link;
if (iname == 0 && ELF_ST_TYPE (isym->st_info) == STT_SECTION
/* Check for a bogus st_shndx to avoid crashing. */
&& isym->st_shndx < elf_numsections (abfd))
{
iname = elf_elfsections (abfd)[isym->st_shndx]->sh_name;
shindex = elf_elfheader (abfd)->e_shstrndx;
}
return bfd_elf_string_from_elf_section (abfd, shindex, iname);
}
const char *
bfd_elf_sym_name (bfd *abfd,
Elf_Internal_Shdr *symtab_hdr,
Elf_Internal_Sym *isym,
asection *sym_sec)
{
const char *name = bfd_elf_sym_name_raw (abfd, symtab_hdr, isym);
if (name == NULL)
name = bfd_symbol_error_name;
else if (sym_sec && *name == '\0')
name = bfd_section_name (sym_sec);
return name;
}
/* Return the name of the group signature symbol. Why isn't the
signature just a string? */
static const char *
group_signature (bfd *abfd, Elf_Internal_Shdr *ghdr)
{
Elf_Internal_Shdr *hdr;
unsigned char esym[sizeof (Elf64_External_Sym)];
Elf_External_Sym_Shndx eshndx;
Elf_Internal_Sym isym;
/* First we need to ensure the symbol table is available. Make sure
that it is a symbol table section. */
if (ghdr->sh_link >= elf_numsections (abfd))
return NULL;
hdr = elf_elfsections (abfd) [ghdr->sh_link];
if (hdr->sh_type != SHT_SYMTAB
|| ! bfd_section_from_shdr (abfd, ghdr->sh_link))
return NULL;
/* Go read the symbol. */
hdr = &elf_tdata (abfd)->symtab_hdr;
if (bfd_elf_get_elf_syms (abfd, hdr, 1, ghdr->sh_info,
&isym, esym, &eshndx) == NULL)
return NULL;
return bfd_elf_sym_name_raw (abfd, hdr, &isym);
}
static bool
is_valid_group_section_header (Elf_Internal_Shdr *shdr, size_t minsize)
{
return (shdr->sh_size >= minsize
&& shdr->sh_entsize == GRP_ENTRY_SIZE
&& shdr->sh_size % GRP_ENTRY_SIZE == 0
&& shdr->bfd_section != NULL);
}
/* Set next_in_group, sec_group list pointers, and group names. */
static bool
process_sht_group_entries (bfd *abfd,
Elf_Internal_Shdr *ghdr, unsigned int gidx)
{
unsigned char *contents;
/* Read the raw contents. */
if (!bfd_malloc_and_get_section (abfd, ghdr->bfd_section, &contents))
{
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: could not read contents of group [%u]"), abfd, gidx);
return false;
}
asection *last_elt = NULL;
const char *gname = NULL;
unsigned char *p = contents + ghdr->sh_size;
while (1)
{
unsigned int idx;
Elf_Internal_Shdr *shdr;
asection *elt;
p -= 4;
idx = H_GET_32 (abfd, p);
if (p == contents)
{
if ((idx & GRP_COMDAT) != 0)
ghdr->bfd_section->flags
|= SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD;
break;
}
if (idx == 0
|| idx >= elf_numsections (abfd)
|| (shdr = elf_elfsections (abfd)[idx])->sh_type == SHT_GROUP
|| ((elt = shdr->bfd_section) != NULL
&& elf_sec_group (elt) != NULL
&& elf_sec_group (elt) != ghdr->bfd_section))
{
_bfd_error_handler
(_("%pB: invalid entry (%#x) in group [%u]"),
abfd, idx, gidx);
continue;
}
/* PR binutils/23199: According to the ELF gABI all sections in
a group must be marked with SHF_GROUP, but some tools
generate broken objects. Fix them up here. */
shdr->sh_flags |= SHF_GROUP;
if (elt == NULL)
{
if (shdr->sh_type != SHT_RELA && shdr->sh_type != SHT_REL)
{
const char *name = bfd_elf_string_from_elf_section
(abfd, elf_elfheader (abfd)->e_shstrndx, shdr->sh_name);
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: unexpected type (%#x) section `%s' in group [%u]"),
abfd, shdr->sh_type, name, gidx);
}
continue;
}
/* Don't try to add a section to elf_next_in_group list twice. */
if (elf_sec_group (elt) != NULL)
continue;
if (last_elt == NULL)
{
/* Start a circular list with one element.
It will be in reverse order to match what gas does. */
elf_next_in_group (elt) = elt;
/* Point the group section to it. */
elf_next_in_group (ghdr->bfd_section) = elt;
gname = group_signature (abfd, ghdr);
if (gname == NULL)
{
free (contents);
return false;
}
}
else
{
elf_next_in_group (elt) = elf_next_in_group (last_elt);
elf_next_in_group (last_elt) = elt;
}
last_elt = elt;
elf_group_name (elt) = gname;
elf_sec_group (elt) = ghdr->bfd_section;
}
free (contents);
return true;
}
bool
_bfd_elf_setup_sections (bfd *abfd)
{
bool result = true;
/* Process SHF_LINK_ORDER. */
for (asection *s = abfd->sections; s != NULL; s = s->next)
{
Elf_Internal_Shdr *this_hdr = &elf_section_data (s)->this_hdr;
if ((this_hdr->sh_flags & SHF_LINK_ORDER) != 0)
{
unsigned int elfsec = this_hdr->sh_link;
/* An sh_link value of 0 is now allowed. It indicates that linked
to section has already been discarded, but that the current
section has been retained for some other reason. This linking
section is still a candidate for later garbage collection
however. */
if (elfsec == 0)
{
elf_linked_to_section (s) = NULL;
}
else
{
asection *linksec = NULL;
if (elfsec < elf_numsections (abfd))
{
this_hdr = elf_elfsections (abfd)[elfsec];
linksec = this_hdr->bfd_section;
}
/* PR 1991, 2008:
Some strip/objcopy may leave an incorrect value in
sh_link. We don't want to proceed. */
if (linksec == NULL)
{
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: sh_link [%d] in section `%pA' is incorrect"),
s->owner, elfsec, s);
result = false;
}
elf_linked_to_section (s) = linksec;
}
}
}
/* Process section groups. */
for (unsigned int i = 1; i < elf_numsections (abfd); i++)
{
Elf_Internal_Shdr *shdr = elf_elfsections (abfd)[i];
if (shdr && shdr->sh_type == SHT_GROUP)
{
if (is_valid_group_section_header (shdr, GRP_ENTRY_SIZE))
{
if (shdr->sh_size >= 2 * GRP_ENTRY_SIZE
&& !process_sht_group_entries (abfd, shdr, i))
result = false;
}
else
{
/* PR binutils/18758: Beware of corrupt binaries with
invalid group data. */
_bfd_error_handler
/* xgettext:c-format */
(_("%pB: section group entry number %u is corrupt"), abfd, i);
result = false;
}
}
}
return result;
}
bool
bfd_elf_is_group_section (bfd *abfd ATTRIBUTE_UNUSED, const asection *sec)
{
return elf_next_in_group (sec) != NULL;
}
const char *
bfd_elf_group_name (bfd *abfd ATTRIBUTE_UNUSED, const asection *sec)
{
if (elf_sec_group (sec) != NULL)
return elf_group_name (sec);
return NULL;
}
/* Make a BFD section from an ELF section. We store a pointer to the
BFD section in the bfd_section field of the header. */
bool
_bfd_elf_make_section_from_shdr (bfd *abfd,
Elf_Internal_Shdr *hdr,
const char *name,
int shindex)
{
asection *newsect;
flagword flags;
const struct elf_backend_data *bed;
unsigned int opb = bfd_octets_per_byte (abfd, NULL);
if (hdr->bfd_section != NULL)
return true;
newsect = bfd_make_section_anyway (abfd, name);
if (newsect == NULL)
return false;
hdr->bfd_section = newsect;
elf_section_data (newsect)->this_hdr = *hdr;
elf_section_data (newsect)->this_idx = shindex;
/* Always use the real type/flags. */
elf_section_type (newsect) = hdr->sh_type;
elf_section_flags (newsect) = hdr->sh_flags;
newsect->filepos = hdr->sh_offset;
flags = SEC_NO_FLAGS;
if (hdr->sh_type != SHT_NOBITS)
flags |= SEC_HAS_CONTENTS;
if (hdr->sh_type == SHT_GROUP)
flags |= SEC_GROUP;
if ((hdr->sh_flags & SHF_ALLOC) != 0)
{
flags |= SEC_ALLOC;
if (hdr->sh_type != SHT_NOBITS)
flags |= SEC_LOAD;
}
if ((hdr->sh_flags & SHF_WRITE) == 0)
flags |= SEC_READONLY;
if ((hdr->sh_flags & SHF_EXECINSTR) != 0)
flags |= SEC_CODE;
else if ((flags & SEC_LOAD) != 0)
flags |= SEC_DATA;
if ((hdr->sh_flags & SHF_MERGE) != 0)
{
flags |= SEC_MERGE;
newsect->entsize = hdr->sh_entsize;
}
if ((hdr->sh_flags & SHF_STRINGS) != 0)
flags |= SEC_STRINGS;
if ((hdr->sh_flags & SHF_TLS) != 0)
flags |= SEC_THREAD_LOCAL;
if ((hdr->sh_flags & SHF_EXCLUDE) != 0)
flags |= SEC_EXCLUDE;
switch (elf_elfheader (abfd)->e_ident[EI_OSABI])
{
/* FIXME: We should not recognize SHF_GNU_MBIND for ELFOSABI_NONE,
but binutils as of 2019-07-23 did not set the EI_OSABI header
byte. */
case ELFOSABI_GNU:
case ELFOSABI_FREEBSD:
if ((hdr->sh_flags & SHF_GNU_RETAIN) != 0)
elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_retain;
/* Fall through */
case ELFOSABI_NONE:
if ((hdr->sh_flags & SHF_GNU_MBIND) != 0)
elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_mbind;
break;
}
if ((flags & SEC_ALLOC) == 0)
{
/* The debugging sections appear to be recognized only by name,
not any sort of flag. Their SEC_ALLOC bits are cleared. */
if (name [0] == '.')
{
if (startswith (name, ".debug")
|| startswith (name, ".gnu.debuglto_.debug_")
|| startswith (name, ".gnu.linkonce.wi.")
|| startswith (name, ".zdebug"))
flags |= SEC_DEBUGGING | SEC_ELF_OCTETS;
else if (startswith (name, GNU_BUILD_ATTRS_SECTION_NAME)
|| startswith (name, ".note.gnu"))
{
flags |= SEC_ELF_OCTETS;
opb = 1;
}
else if (startswith (name, ".line")
|| startswith (name, ".stab")
|| strcmp (name, ".gdb_index") == 0)
flags |= SEC_DEBUGGING;
}
}
if (!bfd_set_section_vma (newsect, hdr->sh_addr / opb)
|| !bfd_set_section_size (newsect, hdr->sh_size)
|| !bfd_set_section_alignment (newsect, bfd_log2 (hdr->sh_addralign
& -hdr->sh_addralign)))
return false;
/* As a GNU extension, if the name begins with .gnu.linkonce, we
only link a single copy of the section. This is used to support
g++. g++ will emit each template expansion in its own section.
The symbols will be defined as weak, so that multiple definitions
are permitted. The GNU linker extension is to actually discard
all but one of the sections. */
if (startswith (name, ".gnu.linkonce")
&& elf_next_in_group (newsect) == NULL)
flags |= SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD;
if (!bfd_set_section_flags (newsect, flags))
return false;
bed = get_elf_backend_data (abfd);
if (bed->elf_backend_section_flags)
if (!bed->elf_backend_section_flags (hdr))
return false;
/* We do not parse the PT_NOTE segments as we are interested even in the
separate debug info files which may have the segments offsets corrupted.
PT_NOTEs from the core files are currently not parsed using BFD. */
if (hdr->sh_type == SHT_NOTE && hdr->sh_size != 0)
{
bfd_byte *contents;
if (!_bfd_elf_mmap_section_contents (abfd, newsect, &contents))
return false;
elf_parse_notes (abfd, (char *) contents, hdr->sh_size,
hdr->sh_offset, hdr->sh_addralign);
_bfd_elf_munmap_section_contents (newsect, contents);
}
if ((newsect->flags & SEC_ALLOC) != 0)
{
Elf_Internal_Phdr *phdr;
unsigned int i, nload;
/* Some ELF linkers produce binaries with all the program header
p_paddr fields zero. If we have such a binary with more than
one PT_LOAD header, then leave the section lma equal to vma
so that we don't create sections with overlapping lma. */
phdr = elf_tdata (abfd)->phdr;
for (nload = 0, i = 0; i < elf_elfheader (abfd)->e_phnum; i++, phdr++)
if (phdr->p_paddr != 0)
break;
else if (phdr->p_type == PT_LOAD && phdr->p_memsz != 0)
++nload;
if (i >= elf_elfheader (abfd)->e_phnum && nload > 1)
return true;
phdr = elf_tdata (abfd)->phdr;
for (i = 0; i < elf_elfheader (abfd)->e_phnum; i++, phdr++)
{
if (((phdr->p_type == PT_LOAD
&& (hdr->sh_flags & SHF_TLS) == 0)
|| phdr->p_type == PT_TLS)
&& ELF_SECTION_IN_SEGMENT (hdr, phdr))
{
if ((newsect->flags & SEC_LOAD) == 0)
newsect->lma = (phdr->p_paddr
+ hdr->sh_addr - phdr->p_vaddr) / opb;
else
/* We used to use the same adjustment for SEC_LOAD
sections, but that doesn't work if the segment
is packed with code from multiple VMAs.
Instead we calculate the section LMA based on
the segment LMA. It is assumed that the
segment will contain sections with contiguous
LMAs, even if the VMAs are not. */
newsect->lma = (phdr->p_paddr
+ hdr->sh_offset - phdr->p_offset) / opb;
/* With contiguous segments, we can't tell from file
offsets whether a section with zero size should
be placed at the end of one segment or the
beginning of the next. Decide based on vaddr. */
if (hdr->sh_addr >= phdr->p_vaddr
&& (hdr->sh_addr + hdr->sh_size
<= phdr->p_vaddr + phdr->p_memsz))
break;
}
}
}
/* Compress/decompress DWARF debug sections with names: .debug_*,
.zdebug_*, .gnu.debuglto_.debug_, after the section flags is set. */
if ((newsect->flags & SEC_DEBUGGING) != 0
&& (newsect->flags & SEC_HAS_CONTENTS) != 0
&& (newsect->flags & SEC_ELF_OCTETS) != 0)
{
enum { nothing, compress, decompress } action = nothing;
int compression_header_size;
bfd_size_type uncompressed_size;
unsigned int uncompressed_align_power;
enum compression_type ch_type = ch_none;
bool compressed
= bfd_is_section_compressed_info (abfd, newsect,
&compression_header_size,
&uncompressed_size,