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9ce0058ca6
darling-gdb/bfd/elf.c
Steve Chamberlain 9ce0058ca6 *** empty log message ***
1991-10-03 14:49:10 +00:00

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/* ELF support for BFD.
Copyright (C) 1991 Free Software Foundation, Inc.
Written by Fred Fish @ Cygnus Support, from information published
in "UNIX System V Release 4, Programmers Guide: ANSI C and
Programming Support Tools".
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., 675 Mass Ave, Cambridge, MA 02139, USA. */
/****************************************
WARNING
This is only a partial ELF implementation,
incorporating only those parts that are
required to get gdb up and running. It is
expected that it will be expanded to a full
ELF implementation at some future date.
Unimplemented stubs call abort() to ensure
that they get proper attention if they are
ever called. The stubs are here since
this version was hacked from the COFF
version, and thus they will probably
go away or get expanded appropriately in a
future version.
fnf@cygnus.com
*****************************************/
/* Problems and other issues to resolve.
(1) BFD expects there to be some fixed number of "sections" in
the object file. I.E. there is a "section_count" variable in the
bfd structure which contains the number of sections. However, ELF
supports multiple "views" of a file. In particular, with current
implementations, executable files typically have two tables, a
program header table and a section header table, both of which
partition the executable.
In ELF-speak, the "linking view" of the file uses the section header
table to access "sections" within the file, and the "execution view"
uses the program header table to access "segments" within the file.
"Segments" typically may contain all the data from one or more
"sections".
Note that the section header table is optional in ELF executables,
but it is this information that is most useful to gdb. If the
section header table is missing, then gdb should probably try
to make do with the program header table. (FIXME)
*/
#include <ansidecl.h>
#include <sysdep.h>
#include "bfd.h"
#include "libbfd.h"
#include "obstack.h"
#include "elf-common.h"
#include "elf-internal.h"
#include "elf-external.h"
/* Forward data declarations */
extern bfd_target elf_little_vec, elf_big_vec;
/* Translate an ELF header in external format into an ELF header in internal
format. */
static void
DEFUN(bfd_swap_ehdr_in,(abfd, src, dst),
bfd *abfd AND
Elf_External_Ehdr *src AND
Elf_Internal_Ehdr *dst)
{
bcopy (src -> e_ident, dst -> e_ident, EI_NIDENT);
dst -> e_type = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_type);
dst -> e_machine = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_machine);
dst -> e_version = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_version);
dst -> e_entry = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_entry);
dst -> e_phoff = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_phoff);
dst -> e_shoff = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_shoff);
dst -> e_flags = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_flags);
dst -> e_ehsize = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_ehsize);
dst -> e_phentsize = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_phentsize);
dst -> e_phnum = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_phnum);
dst -> e_shentsize = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_shentsize);
dst -> e_shnum = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_shnum);
dst -> e_shstrndx = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_shstrndx);
}
/* Translate an ELF section header table entry in external format into an
ELF section header table entry in internal format. */
static void
DEFUN(bfd_swap_shdr_in,(abfd, src, dst),
bfd *abfd AND
Elf_External_Shdr *src AND
Elf_Internal_Shdr *dst)
{
dst -> sh_name = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_name);
dst -> sh_type = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_type);
dst -> sh_flags = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_flags);
dst -> sh_addr = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_addr);
dst -> sh_offset = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_offset);
dst -> sh_size = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_size);
dst -> sh_link = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_link);
dst -> sh_info = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_info);
dst -> sh_addralign = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_addralign);
dst -> sh_entsize = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_entsize);
}
/* Create a new bfd section from an ELF section header. */
static boolean
DEFUN(bfd_section_from_shdr, (abfd, hdr, shstrtab),
bfd *abfd AND
Elf_Internal_Shdr *hdr AND
char *shstrtab)
{
asection *newsect;
char *name;
name = hdr -> sh_name ? shstrtab + hdr -> sh_name : "unnamed";
newsect = bfd_make_section (abfd, name);
newsect -> vma = hdr -> sh_addr;
newsect -> size = hdr -> sh_size;
if (!(hdr -> sh_type == SHT_NOBITS))
{
newsect -> filepos = hdr -> sh_offset;
newsect -> flags |= SEC_HAS_CONTENTS;
}
if (hdr -> sh_flags & SHF_ALLOC)
{
newsect -> flags |= SEC_ALLOC;
if (hdr -> sh_type != SHT_NOBITS)
{
newsect -> flags |= SEC_LOAD;
}
}
if (!(hdr -> sh_flags & SHF_WRITE))
{
newsect -> flags |= SEC_READONLY;
}
if (hdr -> sh_flags & SHF_EXECINSTR)
{
newsect -> flags |= SEC_CODE; /* FIXME: may only contain SOME code */
}
if (hdr -> sh_type == SHT_SYMTAB)
{
abfd -> flags |= HAS_SYMS;
}
return (true);
}
/* Begin processing a given object.
First we validate the file by reading in the ELF header and checking
the magic number.
*/
static bfd_target *
DEFUN (elf_object_p, (abfd), bfd *abfd)
{
Elf_External_Ehdr x_ehdr; /* Elf file header, external form */
Elf_Internal_Ehdr i_ehdr; /* Elf file header, internal form */
Elf_External_Shdr *x_shdr; /* Section header table, external form */
Elf_Internal_Shdr *i_shdr; /* Section header table, internal form */
int shindex;
char *shstrtab; /* Internal copy of section header stringtab */
int shstrtabsize; /* Size of section header string table */
/* Read in the ELF header in external format. */
if (bfd_read ((PTR) &x_ehdr, sizeof (x_ehdr), 1, abfd) != sizeof (x_ehdr))
{
bfd_error = system_call_error;
return (NULL);
}
/* Now check to see if we have a valid ELF file, and one that BFD can
make use of. The magic number must match, the address size ('class')
and byte-swapping must match our XVEC entry, and it must have a
section header table (FIXME: See comments re sections at top of this
file). */
if (x_ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
x_ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
x_ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
x_ehdr.e_ident[EI_MAG3] != ELFMAG3)
{
wrong:
bfd_error = wrong_format;
return (NULL);
}
/* FIXME, Check EI_VERSION here ! */
switch (x_ehdr.e_ident[EI_CLASS]) {
case ELFCLASSNONE: /* address size not specified */
goto wrong; /* No support if can't tell address size */
case ELFCLASS32: /* 32-bit addresses */
break;
case ELFCLASS64: /* 64-bit addresses */
goto wrong; /* FIXME: 64 bits not yet supported */
default:
goto wrong; /* No support if unknown address class */
}
/* Switch xvec to match the specified byte order. */
switch (x_ehdr.e_ident[EI_DATA]) {
case ELFDATA2MSB: /* Big-endian */
abfd->xvec = &elf_big_vec;
break;
case ELFDATA2LSB: /* Little-endian */
abfd->xvec = &elf_little_vec;
case ELFDATANONE: /* No data encoding specified */
default: /* Unknown data encoding specified */
goto wrong;
}
/* Now that we know the byte order, swap in the rest of the header */
bfd_swap_ehdr_in (abfd, &x_ehdr, &i_ehdr);
if (x_ehdr.e_shoff == 0)
goto wrong;
if (i_ehdr.e_type == ET_EXEC || i_ehdr.e_type == ET_DYN)
{
abfd -> flags |= EXEC_P;
}
/* Allocate space for copies of the section header table in external
and internal form, seek to the section header table in the file,
read it in, and convert it to internal form. As a simple sanity
check, verify that the what BFD thinks is the size of each section
header table entry actually matches the size recorded in the file. */
if (i_ehdr.e_shentsize != sizeof (*x_shdr))
goto wrong;
if ((x_shdr = (Elf_External_Shdr *)
bfd_alloc (abfd, sizeof (*x_shdr) * i_ehdr.e_shnum)) == NULL)
{
bfd_error = no_memory;
return (NULL);
}
if ((i_shdr = (Elf_Internal_Shdr *)
bfd_alloc (abfd, sizeof (*i_shdr) * i_ehdr.e_shnum)) == NULL)
{
bfd_error = no_memory;
return (NULL);
}
if (bfd_seek (abfd, i_ehdr.e_shoff, SEEK_SET) == -1)
{
bfd_error = system_call_error;
return (NULL);
}
for (shindex = 0; shindex < i_ehdr.e_shnum; shindex++)
{
if (bfd_read ((PTR) (x_shdr + shindex), sizeof (*x_shdr), 1, abfd)
!= sizeof (*x_shdr))
{
bfd_error = system_call_error;
return (NULL);
}
bfd_swap_shdr_in (abfd, x_shdr + shindex, i_shdr + shindex);
}
/* Read in the string table containing the names of the sections. We
will need the base pointer to this table later. */
shstrtabsize = i_shdr[i_ehdr.e_shstrndx].sh_size;
if ((shstrtab = bfd_alloc (abfd, shstrtabsize)) == NULL)
{
bfd_error = no_memory;
return (NULL);
}
if (bfd_seek (abfd, i_shdr[i_ehdr.e_shstrndx].sh_offset, SEEK_SET) == -1)
{
bfd_error = system_call_error;
return (NULL);
}
if (bfd_read ((PTR) shstrtab, shstrtabsize, 1, abfd) != shstrtabsize)
{
bfd_error = system_call_error;
return (NULL);
}
/* Once all of the section headers have been read and converted, we
can start processing them. */
for (shindex = 0; shindex < i_ehdr.e_shnum; shindex++)
{
bfd_section_from_shdr (abfd, i_shdr + shindex, shstrtab);
}
return (abfd->xvec);
}
static boolean
DEFUN (elf_mkobject, (abfd), bfd *abfd)
{
fprintf (stderr, "elf_mkobject unimplemented\n");
fflush (stderr);
abort ();
return (false);
}
static boolean
DEFUN (elf_write_object_contents, (abfd), bfd *abfd)
{
fprintf (stderr, "elf_write_object_contents unimplemented\n");
fflush (stderr);
abort ();
return (false);
}
static boolean
DEFUN (elf_set_section_contents, (abfd, section, location, offset, count),
bfd *abfd AND
sec_ptr section AND
PTR location AND
file_ptr offset AND
bfd_size_type count)
{
fprintf (stderr, "elf_set_section_contents unimplemented\n");
fflush (stderr);
abort ();
return (false);
}
#define elf_new_section_hook _bfd_dummy_new_section_hook
#define elf_core_file_failing_command _bfd_dummy_core_file_failing_command
#define elf_core_file_failing_signal _bfd_dummy_core_file_failing_signal
#define elf_core_file_matches_executable_p _bfd_dummy_core_file_matches_executable_p
#define elf_slurp_armap bfd_false
#define elf_slurp_extended_name_table _bfd_slurp_extended_name_table
#define elf_truncate_arname bfd_dont_truncate_arname
#define elf_openr_next_archived_file bfd_generic_openr_next_archived_file
#define elf_generic_stat_arch_elt bfd_generic_stat_arch_elt
#define elf_get_section_contents bfd_generic_get_section_contents
#define elf_close_and_cleanup bfd_generic_close_and_cleanup
#define elf_bfd_debug_info_start bfd_void
#define elf_bfd_debug_info_end bfd_void
#define elf_bfd_debug_info_accumulate (PROTO(void,(*),(bfd*, struct sec *))) bfd_void
#define elf_write_armap bfd_false
static unsigned int
elf_get_symtab_upper_bound(abfd)
bfd *abfd;
{
fprintf (stderr, "elf_get_symtab_upper_bound unimplemented\n");
fflush (stderr);
abort ();
return (0);
}
static unsigned int
elf_get_reloc_upper_bound (abfd, asect)
bfd *abfd;
sec_ptr asect;
{
fprintf (stderr, "elf_get_reloc_upper_bound unimplemented\n");
fflush (stderr);
abort ();
return (0);
}
static unsigned int
elf_canonicalize_reloc (abfd, section, relptr, symbols)
bfd *abfd;
sec_ptr section;
arelent **relptr;
asymbol **symbols;
{
fprintf (stderr, "elf_canonicalize_reloc unimplemented\n");
fflush (stderr);
abort ();
return (0);
}
static unsigned int
elf_get_symtab (abfd, alocation)
bfd *abfd;
asymbol **alocation;
{
fprintf (stderr, "elf_get_symtab unimplemented\n");
fflush (stderr);
abort ();
return (0);
}
static asymbol *
elf_make_empty_symbol(abfd)
bfd *abfd;
{
fprintf (stderr, "elf_make_empty_symbol unimplemented\n");
fflush (stderr);
abort ();
return (NULL);
}
static void
DEFUN (elf_print_symbol,(ignore_abfd, filep, symbol, how),
bfd *ignore_abfd AND
PTR filep AND
asymbol *symbol AND
bfd_print_symbol_enum_type how)
{
fprintf (stderr, "elf_print_symbol unimplemented\n");
fflush (stderr);
abort ();
}
static alent *
DEFUN (elf_get_lineno,(ignore_abfd, symbol),
bfd *ignore_abfd AND
asymbol *symbol)
{
fprintf (stderr, "elf_get_lineno unimplemented\n");
fflush (stderr);
abort ();
return (NULL);
}
static boolean
DEFUN (elf_set_arch_mach,(abfd, arch, machine),
bfd *abfd AND
enum bfd_architecture arch AND
unsigned long machine)
{
fprintf (stderr, "elf_set_arch_mach unimplemented\n");
fflush (stderr);
/* Allow any architecture to be supported by the elf backend */
return bfd_default_set_arch_mach(abfd, arch, machine);
}
static boolean
DEFUN (elf_find_nearest_line,(abfd,
section,
symbols,
offset,
filename_ptr,
functionname_ptr,
line_ptr),
bfd *abfd AND
asection *section AND
asymbol **symbols AND
bfd_vma offset AND
CONST char **filename_ptr AND
CONST char **functionname_ptr AND
unsigned int *line_ptr)
{
fprintf (stderr, "elf_find_nearest_line unimplemented\n");
fflush (stderr);
abort ();
return (false);
}
static int
DEFUN (elf_sizeof_headers, (abfd, reloc),
bfd *abfd AND
boolean reloc)
{
fprintf (stderr, "elf_sizeof_headers unimplemented\n");
fflush (stderr);
abort ();
return (0);
}
/* This structure contains everything that BFD knows about a target.
It includes things like its byte order, name, what routines to call
to do various operations, etc. Every BFD points to a target structure
with its "xvec" member.
There are two such structures here: one for big-endian machines and
one for little-endian machines. */
bfd_target elf_big_vec =
{
/* name: identify kind of target */
"elf-big",
/* flavour: general indication about file */
bfd_target_elf_flavour_enum,
/* byteorder_big_p: data is big endian */
true,
/* header_byteorder_big_p: header is also big endian */
true,
/* object_flags: mask of all file flags */
(HAS_RELOC | EXEC_P | HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS |
DYNAMIC | WP_TEXT),
/* section_flags: mask of all section flags */
(SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY |
SEC_DATA),
/* ar_pad_char: pad character for filenames within an archive header
FIXME: this really has nothing to do with ELF, this is a characteristic
of the archiver and/or os and should be independently tunable */
'/',
/* ar_max_namelen: maximum number of characters in an archive header
FIXME: this really has nothing to do with ELF, this is a characteristic
of the archiver and should be independently tunable. This value is
a WAG (wild a** guess) */
15,
/* align_power_min: minimum alignment restriction for any section
FIXME: this value may be target machine dependent */
3,
/* Routines to byte-swap various sized integers from the data sections */
_do_getb64, _do_putb64, _do_getb32, _do_putb32, _do_getb16, _do_putb16,
/* Routines to byte-swap various sized integers from the file headers */
_do_getb64, _do_putb64, _do_getb32, _do_putb32, _do_getb16, _do_putb16,
/* bfd_check_format: check the format of a file being read */
{ _bfd_dummy_target,
elf_object_p,
bfd_generic_archive_p,
_bfd_dummy_target
},
/* bfd_set_format: set the format of a file being written */
{ bfd_false,
elf_mkobject,
_bfd_generic_mkarchive,
bfd_false
},
/* bfd_write_contents: write cached information into a file being written */
{ bfd_false,
elf_write_object_contents,
_bfd_write_archive_contents,
bfd_false
},
/* Initialize a jump table with the standard macro. All names start
with "elf" */
JUMP_TABLE(elf),
/* SWAP_TABLE */
NULL, NULL, NULL
};
bfd_target elf_little_vec =
{
/* name: identify kind of target */
"elf-little",
/* flavour: general indication about file */
bfd_target_elf_flavour_enum,
/* byteorder_big_p: data is big endian */
false, /* Nope -- this one's little endian */
/* header_byteorder_big_p: header is also big endian */
false, /* Nope -- this one's little endian */
/* object_flags: mask of all file flags */
(HAS_RELOC | EXEC_P | HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS |
DYNAMIC | WP_TEXT),
/* section_flags: mask of all section flags */
(SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY |
SEC_DATA),
/* ar_pad_char: pad character for filenames within an archive header
FIXME: this really has nothing to do with ELF, this is a characteristic
of the archiver and/or os and should be independently tunable */
'/',
/* ar_max_namelen: maximum number of characters in an archive header
FIXME: this really has nothing to do with ELF, this is a characteristic
of the archiver and should be independently tunable. This value is
a WAG (wild a** guess) */
15,
/* align_power_min: minimum alignment restriction for any section
FIXME: this value may be target machine dependent */
3,
/* Routines to byte-swap various sized integers from the data sections */
_do_getl64, _do_putl64, _do_getl32, _do_putl32, _do_getl16, _do_putl16,
/* Routines to byte-swap various sized integers from the file headers */
_do_getl64, _do_putl64, _do_getl32, _do_putl32, _do_getl16, _do_putl16,
/* bfd_check_format: check the format of a file being read */
{ _bfd_dummy_target,
elf_object_p,
bfd_generic_archive_p,
_bfd_dummy_target
},
/* bfd_set_format: set the format of a file being written */
{ bfd_false,
elf_mkobject,
_bfd_generic_mkarchive,
bfd_false
},
/* bfd_write_contents: write cached information into a file being written */
{ bfd_false,
elf_write_object_contents,
_bfd_write_archive_contents,
bfd_false
},
/* Initialize a jump table with the standard macro. All names start
with "elf" */
JUMP_TABLE(elf),
/* SWAP_TABLE */
NULL, NULL, NULL
};
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