aout-encap.c

早期freebsd实现

/* BFD back-end for a.out files encapsulated with COFF headers.
   Copyright (C) 1990-1991 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* THIS MODULE IS NOT FINISHED.  IT PROBABLY DOESN'T EVEN COMPILE.  */

#if 0
#define	PAGE_SIZE	4096
#define	SEGMENT_SIZE	PAGE_SIZE
#define TEXT_START_ADDR 0
#define ARCH 32
#define BYTES_IN_WORD 4
#endif

#include "bfd.h"
#include <sysdep.h>
#include "libbfd.h"
#include <aout/aout64.h>
#include "aout/stab_gnu.h"
#include "aout/ar.h"
#include "libaout.h"           /* BFD a.out internal data structures */

bfd_target *encap_real_callback ();

bfd_target *
DEFUN(encap_object_p,(abfd),
     bfd *abfd)
{
  unsigned char magicbuf[4]; /* Raw bytes of magic number from file */
  unsigned long magic;		/* Swapped magic number */
  short coff_magic;
  struct external_exec exec_bytes;
  struct internal_exec exec;

  bfd_error = system_call_error;

  if (bfd_read ((PTR)magicbuf, 1, sizeof (magicbuf), abfd) !=
      sizeof (magicbuf))
    return 0;
  
  coff_magic = bfd_h_get_16 (abfd, magicbuf);
  if (coff_magic != COFF_MAGIC)
    return 0;			/* Not an encap coff file */

  __header_offset_temp==COFF_MAGIC ? sizeof(struct coffheader) : 0)
  (fseek ((f), HEADER_OFFSET((f)), 1))

  magic = bfd_h_get_32 (abfd, magicbuf);

  if (N_BADMAG (*((struct internal_exec *) &magic))) return 0;

  struct external_exec exec_bytes;
  if (bfd_read ((PTR) &exec_bytes, 1, EXEC_BYTES_SIZE, abfd)
      != EXEC_BYTES_SIZE) {
    bfd_error = wrong_format;
    return 0;
  }
  NAME(aout,swap_exec_header_in)(abfd, &exec_bytes, &exec);

  return aout_32_some_aout_object_p (abfd, &exec, encap_realcallback);
}

/* Finish up the reading of a encapsulated-coff a.out file header */
bfd_target *
DEFUN(encap_real_callback,(abfd),
      bfd *abfd)
{
  struct internal_exec *execp = exec_hdr (abfd);
  
  MY(callback)(abfd, execp);
  
  /* If we have a coff header, it can give us better values for
     text_start and exec_data_start.  This is particularly useful
     for remote debugging of embedded systems.  */
  if (N_FLAGS(exec_aouthdr) & N_FLAGS_COFF_ENCAPSULATE)
  {
	  struct coffheader ch;
	  int val;
	  val = lseek (execchan, -(sizeof (AOUTHDR) + sizeof (ch)), 1);
	  if (val == -1)
		  perror_with_name (filename);
	  val = myread (execchan, &ch, sizeof (ch));
	  if (val < 0)
		  perror_with_name (filename);
	  text_start = ch.text_start;
	  exec_data_start = ch.data_start;
  } else
	 {
	  text_start =
	    IS_OBJECT_FILE (exec_aouthdr) ? 0 : N_TXTADDR (exec_aouthdr);
	  exec_data_start = IS_OBJECT_FILE (exec_aouthdr)
	    ? exec_aouthdr.a_text : N_DATADDR (exec_aouthdr);
  }

  /* Determine the architecture and machine type of the object file.  */
  bfd_default_set_arch_mach(abfd, bfd_arch_m68k, 0); /* FIXME */

  return abfd->xvec;
}

/* Write an object file in Encapsulated COFF format.
   Section contents have already been written.  We write the
   file header, symbols, and relocation.  */

boolean
DEFUN(encap_write_object_contents,(abfd),
      bfd *abfd)
{
  bfd_size_type data_pad = 0;
  struct external_exec exec_bytes;
  struct internal_exec *execp = exec_hdr (abfd);

/****** FIXME:  Fragments from the old GNU LD program for dealing with
        encap coff.  */
struct coffheader coffheader;
int need_coff_header;

  /* Determine whether to count the header as part of
     the text size, and initialize the text size accordingly.
     This depends on the kind of system and on the output format selected.  */

  N_SET_MAGIC (outheader, magic);
#ifdef INITIALIZE_HEADER
  INITIALIZE_HEADER;
#endif

  text_size = sizeof (struct exec);
#ifdef COFF_ENCAPSULATE
  if (relocatable_output == 0 && file_table[0].just_syms_flag == 0)
    {
      need_coff_header = 1;
      /* set this flag now, since it will change the values of N_TXTOFF, etc */
      N_SET_FLAGS (outheader, N_FLAGS_COFF_ENCAPSULATE);
      text_size += sizeof (struct coffheader);
    }
#endif

#ifdef COFF_ENCAPSULATE
  if (need_coff_header)
    {
      /* We are encapsulating BSD format within COFF format.  */
      struct coffscn *tp, *dp, *bp;

      tp = &coffheader.scns[0];
      dp = &coffheader.scns[1];
      bp = &coffheader.scns[2];

      strcpy (tp->s_name, ".text");
      tp->s_paddr = text_start;
      tp->s_vaddr = text_start;
      tp->s_size = text_size;
      tp->s_scnptr = sizeof (struct coffheader) + sizeof (struct exec);
      tp->s_relptr = 0;
      tp->s_lnnoptr = 0;
      tp->s_nreloc = 0;
      tp->s_nlnno = 0;
      tp->s_flags = 0x20;
      strcpy (dp->s_name, ".data");
      dp->s_paddr = data_start;
      dp->s_vaddr = data_start;
      dp->s_size = data_size;
      dp->s_scnptr = tp->s_scnptr + tp->s_size;
      dp->s_relptr = 0;
      dp->s_lnnoptr = 0;
      dp->s_nreloc = 0;
      dp->s_nlnno = 0;
      dp->s_flags = 0x40;
      strcpy (bp->s_name, ".bss");
      bp->s_paddr = dp->s_vaddr + dp->s_size;
      bp->s_vaddr = bp->s_paddr;
      bp->s_size = bss_size;
      bp->s_scnptr = 0;
      bp->s_relptr = 0;
      bp->s_lnnoptr = 0;
      bp->s_nreloc = 0;
      bp->s_nlnno = 0;
      bp->s_flags = 0x80;

      coffheader.f_magic = COFF_MAGIC;
      coffheader.f_nscns = 3;
      /* store an unlikely time so programs can
       * tell that there is a bsd header
       */
      coffheader.f_timdat = 1;
      coffheader.f_symptr = 0;
      coffheader.f_nsyms = 0;
      coffheader.f_opthdr = 28;
      coffheader.f_flags = 0x103;
      /* aouthdr */
      coffheader.magic = ZMAGIC;
      coffheader.vstamp = 0;
      coffheader.tsize = tp->s_size;
      coffheader.dsize = dp->s_size;
      coffheader.bsize = bp->s_size;
      coffheader.entry = outheader.a_entry;
      coffheader.text_start = tp->s_vaddr;
      coffheader.data_start = dp->s_vaddr;
    }
#endif

#ifdef COFF_ENCAPSULATE
  if (need_coff_header)
    mywrite (&coffheader, sizeof coffheader, 1, outdesc);
#endif

#ifndef COFF_ENCAPSULATE
  padfile (N_TXTOFF (outheader) - sizeof outheader, outdesc);
#endif

  text_size -= N_TXTOFF (outheader);
  WRITE_HEADERS(abfd, execp);
  return true;
}

#define MY_write_object_content encap_write_object_contents
#define MY_object_p encap_object_p

#include "aout-target.h"