aoutx.h

早期freebsd实现

/* BFD semi-generic back-end for a.out binaries.
   Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
   Written by Cygnus Support.

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.  */

/*
SECTION
	a.out backends


DESCRIPTION

	BFD supports a number of different flavours of a.out format,
	though the major differences are only the sizes of the
	structures on disk, and the shape of the relocation
	information. 

	The support is split into a basic support file @code{aoutx.h}
	and other files which derive functions from the base. One
	derivation file is @code{aoutf1.h} (for a.out flavour 1), and
	adds to the basic a.out functions support for sun3, sun4, 386
	and 29k a.out files, to create a target jump vector for a
	specific target. 

	This information is further split out into more specific files
	for each machine, including @code{sunos.c} for sun3 and sun4,
	@code{newsos3.c} for the Sony NEWS, and @code{demo64.c} for a
	demonstration of a 64 bit a.out format.

	The base file @code{aoutx.h} defines general mechanisms for
	reading and writing records to and from disk, and various
	other methods which BFD requires. It is included by
	@code{aout32.c} and @code{aout64.c} to form the names
	aout_32_swap_exec_header_in, aout_64_swap_exec_header_in, etc.

	As an example, this is what goes on to make the back end for a
	sun4, from aout32.c 

|	#define ARCH_SIZE 32
|	#include "aoutx.h"

	Which exports names:

|	...
|	aout_32_canonicalize_reloc
|	aout_32_find_nearest_line
|	aout_32_get_lineno
|	aout_32_get_reloc_upper_bound
|	...

	from sunos.c

|	#define ARCH 32
|	#define TARGET_NAME "a.out-sunos-big"
|	#define VECNAME    sunos_big_vec
|	#include "aoutf1.h"

	requires all the names from aout32.c, and produces the jump vector

|	sunos_big_vec

	The file host-aout.c is a special case.  It is for a large set
	of hosts that use ``more or less standard'' a.out files, and
	for which cross-debugging is not interesting.  It uses the
	standard 32-bit a.out support routines, but determines the
	file offsets and addresses of the text, data, and BSS
	sections, the machine architecture and machine type, and the
	entry point address, in a host-dependent manner.  Once these
	values have been determined, generic code is used to handle
	the  object file. 

	When porting it to run on a new system, you must supply:

|        HOST_PAGE_SIZE
|        HOST_SEGMENT_SIZE
|        HOST_MACHINE_ARCH       (optional)
|        HOST_MACHINE_MACHINE    (optional)
|        HOST_TEXT_START_ADDR
|        HOST_STACK_END_ADDR

	in the file <<../include/sys/h-XXX.h>> (for your host).  These
	values, plus the structures and macros defined in <<a.out.h>> on
	your host system, will produce a BFD target that will access
	ordinary a.out files on your host. To configure a new machine
	to use <<host-aout.c>., specify: 

|	TDEFAULTS = -DDEFAULT_VECTOR=host_aout_big_vec
|	TDEPFILES= host-aout.o trad-core.o

	in the <<config/mt-XXX>> file, and modify configure.in to use the
	<<mt-XXX>> file (by setting "<<bfd_target=XXX>>") when your
	configuration is selected.

*/

/* Some assumptions:
   * Any BFD with D_PAGED set is ZMAGIC, and vice versa.
     Doesn't matter what the setting of WP_TEXT is on output, but it'll
     get set on input.
   * Any BFD with D_PAGED clear and WP_TEXT set is NMAGIC.
   * Any BFD with both flags clear is OMAGIC.
   (Just want to make these explicit, so the conditions tested in this
   file make sense if you're more familiar with a.out than with BFD.)  */

#define KEEPIT flags
#define KEEPITTYPE int

#include "bfd.h"
#include <sysdep.h>
#include <ansidecl.h>

struct external_exec;
#include "libaout.h"
#include "libbfd.h"
#include "aout/aout64.h"
#include "aout/stab_gnu.h"
#include "aout/ar.h"

extern void (*bfd_error_trap)();

/*
SUBSECTION
	relocations

DESCRIPTION
	The file @code{aoutx.h} caters for both the @emph{standard}
	and @emph{extended} forms of a.out relocation records.

	The standard records are characterised by containing only an
	address, a symbol index and a type field. The extended records
	(used on 29ks and sparcs) also have a full integer for an
	addend. 

*/
#define CTOR_TABLE_RELOC_IDX 2

#define howto_table_ext NAME(aout,ext_howto_table)
#define howto_table_std NAME(aout,std_howto_table)

reloc_howto_type howto_table_ext[] = 
{
  HOWTO(RELOC_8,      0,  0,  	8,  false, 0, true,  true,0,"8",      false, 0,0x000000ff, false),
  HOWTO(RELOC_16,     0,  1, 	16, false, 0, true,  true,0,"16",      false, 0,0x0000ffff, false),
  HOWTO(RELOC_32,     0,  2, 	32, false, 0, true,  true,0,"32",      false, 0,0xffffffff, false),
  HOWTO(RELOC_DISP8,  0,  0, 	8,  true,  0, false, true,0,"DISP8", 	false, 0,0x000000ff, false),
  HOWTO(RELOC_DISP16, 0,  1, 	16, true,  0, false, true,0,"DISP16", 	false, 0,0x0000ffff, false),
  HOWTO(RELOC_DISP32, 0,  2, 	32, true,  0, false, true,0,"DISP32", 	false, 0,0xffffffff, false),
  HOWTO(RELOC_WDISP30,2,  2, 	30, true,  0, false, true,0,"WDISP30", 	false, 0,0x3fffffff, false),
  HOWTO(RELOC_WDISP22,2,  2, 	22, true,  0, false, true,0,"WDISP22", 	false, 0,0x003fffff, false),
  HOWTO(RELOC_HI22,   10, 2, 	22, false, 0, false, true,0,"HI22",	false, 0,0x003fffff, false),
  HOWTO(RELOC_22,      0, 2, 	22, false, 0, false, true,0,"22",       false, 0,0x003fffff, false),
  HOWTO(RELOC_13, 	0, 2, 	13, false, 0, false, true,0,"13",       false, 0,0x00001fff, false),
  HOWTO(RELOC_LO10, 	0, 2, 	10, false, 0, false, true,0,"LO10",     false, 0,0x000003ff, false),
  HOWTO(RELOC_SFA_BASE,0, 2, 	32, false, 0, false, true,0,"SFA_BASE", false, 0,0xffffffff, false),
  HOWTO(RELOC_SFA_OFF13,0,2, 	32, false, 0, false, true,0,"SFA_OFF13",false, 0,0xffffffff, false),
  HOWTO(RELOC_BASE10, 0,  2, 	16, false, 0, false, true,0,"BASE10",   false, 0,0x0000ffff, false),
  HOWTO(RELOC_BASE13, 0,  2,	13, false, 0, false, true,0,"BASE13",   false, 0,0x00001fff, false),
  HOWTO(RELOC_BASE22, 0,  2,	0,  false, 0, false, true,0,"BASE22",   false, 0,0x00000000, false),
  HOWTO(RELOC_PC10,   0,  2,	10, false, 0, false, true,0,"PC10",	false, 0,0x000003ff, false),
  HOWTO(RELOC_PC22,   0,  2,	22, false, 0, false, true,0,"PC22",	false, 0,0x003fffff, false),
  HOWTO(RELOC_JMP_TBL,0,  2,	32, false, 0, false, true,0,"JMP_TBL",	false, 0,0xffffffff, false),
  HOWTO(RELOC_SEGOFF16,0, 2,	0,  false, 0, false, true,0,"SEGOFF16",	false, 0,0x00000000, false),
  HOWTO(RELOC_GLOB_DAT,0, 2,	0,  false, 0, false, true,0,"GLOB_DAT",	false, 0,0x00000000, false),
  HOWTO(RELOC_JMP_SLOT,0, 2,	0,  false, 0, false, true,0,"JMP_SLOT",	false, 0,0x00000000, false),
  HOWTO(RELOC_RELATIVE,0, 2,	0,  false, 0, false,	true,0,"RELATIVE",	false, 0,0x00000000, false),
};

/* Convert standard reloc records to "arelent" format (incl byte swap).  */

reloc_howto_type howto_table_std[] = {
  /* type           rs   size bsz  pcrel bitpos  abs ovrf sf name    part_inpl   readmask  setmask  pcdone */
HOWTO( 0,	       0,  0,  	8,  false, 0, true,  true,0,"8",	true, 0x000000ff,0x000000ff, false),
HOWTO( 1,	       0,  1, 	16, false, 0, true,  true,0,"16",	true, 0x0000ffff,0x0000ffff, false),
HOWTO( 2,	       0,  2, 	32, false, 0, true,  true,0,"32",	true, 0xffffffff,0xffffffff, false),
HOWTO( 3,	       0,  3, 	64, false, 0, true,  true,0,"64",       true, 0xdeaddead,0xdeaddead, false),
HOWTO( 4,	       0,  0, 	8,  true,  0, false, true,0,"DISP8",    true, 0x000000ff,0x000000ff, false),
HOWTO( 5,	       0,  1, 	16, true,  0, false, true,0,"DISP16",   true, 0x0000ffff,0x0000ffff, false),
HOWTO( 6,	       0,  2, 	32, true,  0, false, true,0,"DISP32",   true, 0xffffffff,0xffffffff, false),
HOWTO( 7,	       0,  3, 	64, true,  0, false, true,0,"DISP64",   true, 0xfeedface,0xfeedface, false),
};

CONST struct reloc_howto_struct *
DEFUN(NAME(aout,reloc_type_lookup),(abfd,code),
      bfd *abfd AND
      bfd_reloc_code_real_type code)
{
#define EXT(i,j)	case i: return &howto_table_ext[j]
#define STD(i,j)	case i: return &howto_table_std[j]
  int ext = obj_reloc_entry_size (abfd) == RELOC_EXT_SIZE;
  if (code == BFD_RELOC_CTOR)
    switch (bfd_get_arch_info (abfd)->bits_per_address)
      {
      case 32:
	code = BFD_RELOC_32;
	break;
      }
  if (ext)
    switch (code)
      {
	EXT (BFD_RELOC_32, 2);
	EXT (BFD_RELOC_HI22, 8);
	EXT (BFD_RELOC_LO10, 11);
	EXT (BFD_RELOC_32_PCREL_S2, 6);
      }
  else
    /* std relocs */
    switch (code)
      {
	STD (BFD_RELOC_16, 1);
	STD (BFD_RELOC_32, 2);
	STD (BFD_RELOC_8_PCREL, 4);
	STD (BFD_RELOC_16_PCREL, 5);
	STD (BFD_RELOC_32_PCREL, 6);
      }
  return 0;
}

extern bfd_error_vector_type bfd_error_vector;

/*
SUBSECTION
	Internal Entry Points

DESCRIPTION
	@code{aoutx.h} exports several routines for accessing the
	contents of an a.out file, which are gathered and exported in
	turn by various format specific files (eg sunos.c).

*/

/*
FUNCTION
	 aout_<size>_swap_exec_header_in

DESCRIPTION
	Swaps the information in an executable header taken from a raw
	byte stream memory image, into the internal exec_header
	structure.

EXAMPLE
	void aout_<size>_swap_exec_header_in,
           (bfd *abfd,
            struct external_exec *raw_bytes,
            struct internal_exec *execp);
*/
	 
void
DEFUN(NAME(aout,swap_exec_header_in),(abfd, raw_bytes, execp),
      bfd *abfd AND
      struct external_exec *raw_bytes AND
      struct internal_exec *execp)
{
  struct external_exec *bytes = (struct external_exec *)raw_bytes;

  /* The internal_exec structure has some fields that are unused in this
     configuration (IE for i960), so ensure that all such uninitialized
     fields are zero'd out.  There are places where two of these structs
     are memcmp'd, and thus the contents do matter. */
  memset (execp, 0, sizeof (struct internal_exec));
  /* Now fill in fields in the execp, from the bytes in the raw data.  */
  execp->a_info   = bfd_h_get_32 (abfd, bytes->e_info);
  execp->a_text   = GET_WORD (abfd, bytes->e_text);
  execp->a_data   = GET_WORD (abfd, bytes->e_data);
  execp->a_bss    = GET_WORD (abfd, bytes->e_bss);
  execp->a_syms   = GET_WORD (abfd, bytes->e_syms);
  execp->a_entry  = GET_WORD (abfd, bytes->e_entry);
  execp->a_trsize = GET_WORD (abfd, bytes->e_trsize);
  execp->a_drsize = GET_WORD (abfd, bytes->e_drsize);
}

/*
FUNCTION
	aout_<size>_swap_exec_header_out

DESCRIPTION
	Swaps the information in an internal exec header structure
	into the supplied buffer ready for writing to disk.

EXAMPLE
	void aout_<size>_swap_exec_header_out
	  (bfd *abfd,
	   struct internal_exec *execp,
	   struct external_exec *raw_bytes);
*/
void
DEFUN(NAME(aout,swap_exec_header_out),(abfd, execp, raw_bytes),
     bfd *abfd AND
     struct internal_exec *execp AND 
     struct external_exec *raw_bytes)
{
  struct external_exec *bytes = (struct external_exec *)raw_bytes;

  /* Now fill in fields in the raw data, from the fields in the exec struct. */
  bfd_h_put_32 (abfd, execp->a_info  , bytes->e_info);
  PUT_WORD (abfd, execp->a_text  , bytes->e_text);
  PUT_WORD (abfd, execp->a_data  , bytes->e_data);
  PUT_WORD (abfd, execp->a_bss   , bytes->e_bss);
  PUT_WORD (abfd, execp->a_syms  , bytes->e_syms);
  PUT_WORD (abfd, execp->a_entry , bytes->e_entry);
  PUT_WORD (abfd, execp->a_trsize, bytes->e_trsize);
  PUT_WORD (abfd, execp->a_drsize, bytes->e_drsize);
}



/*
FUNCTION
	aout_<size>_some_aout_object_p

DESCRIPTION
	Some A.OUT variant thinks that the file whose format we're
	checking is an a.out file.  Do some more checking, and set up
	for access if it really is.  Call back to the calling
	environments "finish up" function just before returning, to
	handle any last-minute setup.  

EXAMPLE
	bfd_target *aout_<size>_some_aout_object_p
	 (bfd *abfd,
	  bfd_target *(*callback_to_real_object_p)());
*/
 
bfd_target *
DEFUN(NAME(aout,some_aout_object_p),(abfd, execp, callback_to_real_object_p),
      bfd *abfd AND
      struct internal_exec *execp AND
      bfd_target *(*callback_to_real_object_p) ())
{
  struct aout_data_struct *rawptr, *oldrawptr;
  bfd_target *result;

  rawptr = (struct aout_data_struct  *) bfd_zalloc (abfd, sizeof (struct aout_data_struct ));
  if (rawptr == NULL) {
    bfd_error = no_memory;
    return 0;
  }

  oldrawptr = abfd->tdata.aout_data;
  abfd->tdata.aout_data = rawptr;
  abfd->tdata.aout_data->a.hdr = &rawptr->e;
  *(abfd->tdata.aout_data->a.hdr) = *execp;	/* Copy in the internal_exec struct */
  execp = abfd->tdata.aout_data->a.hdr;

  /* Set the file flags */
  abfd->flags = NO_FLAGS;
  if (execp->a_drsize || execp->a_trsize)
    abfd->flags |= HAS_RELOC;
  /* Setting of EXEC_P has been deferred to the bottom of this function */
  if (execp->a_syms) 
    abfd->flags |= HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS;

  if (N_MAGIC (*execp) == ZMAGIC)
    {
      abfd->flags |= D_PAGED|WP_TEXT;
      adata(abfd).magic = z_magic;
    }
  else if (N_MAGIC (*execp) == NMAGIC)
    {
      abfd->flags |= WP_TEXT;
      adata(abfd).magic = n_magic;
    }
  else
    adata(abfd).magic = o_magic;

  bfd_get_start_address (abfd) = execp->a_entry;

  obj_aout_symbols (abfd) = (aout_symbol_type *)NULL;
  bfd_get_symcount (abfd) = execp->a_syms / sizeof (struct external_nlist);

  /* The default relocation entry size is that of traditional V7 Unix.  */
  obj_reloc_entry_size (abfd) = RELOC_STD_SIZE;

  /* The default symbol entry size is that of traditional Unix. */
  obj_symbol_entry_size (abfd) = EXTERNAL_NLIST_SIZE;

  /* create the sections.  This is raunchy, but bfd_close wants to reclaim
     them */

  obj_textsec (abfd) = bfd_make_section_old_way (abfd, ".text");
  obj_datasec (abfd) = bfd_make_section_old_way (abfd, ".data");
  obj_bsssec (abfd) = bfd_make_section_old_way (abfd, ".bss");

#if 0
  (void)bfd_make_section (abfd, ".text");
  (void)bfd_make_section (abfd, ".data");
  (void)bfd_make_section (abfd, ".bss");
#endif

  obj_datasec (abfd)->_raw_size = execp->a_data;
  obj_bsssec (abfd)->_raw_size = execp->a_bss;

  obj_textsec (abfd)->flags = (execp->a_trsize != 0 ?
       (SEC_ALLOC | SEC_LOAD | SEC_CODE | SEC_HAS_CONTENTS | SEC_RELOC) :
       (SEC_ALLOC | SEC_LOAD | SEC_CODE | SEC_HAS_CONTENTS));
  obj_datasec (abfd)->flags = (execp->a_drsize != 0 ?
       (SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS | SEC_RELOC) :
       (SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS));
  obj_bsssec (abfd)->flags = SEC_ALLOC;

#ifdef THIS_IS_ONLY_DOCUMENTATION
  /* The common code can't fill in these things because they depend
     on either the start address of the text segment, the rounding
     up of virtual addersses between segments, or the starting file 
     position of the text segment -- all of which varies among different
     versions of a.out.  */

  /* Call back to the format-dependent code to fill in the rest of the 
     fields and do any further cleanup.  Things that should be filled
     in by the callback:  */

  struct exec *execp = exec_hdr (abfd);