aoutx.h

早期freebsd实现

  obj_textsec (abfd)->size = N_TXTSIZE(*execp);
  obj_textsec (abfd)->raw_size = N_TXTSIZE(*execp);
  /* data and bss are already filled in since they're so standard */

  /* The virtual memory addresses of the sections */
  obj_textsec (abfd)->vma = N_TXTADDR(*execp);
  obj_datasec (abfd)->vma = N_DATADDR(*execp);
  obj_bsssec  (abfd)->vma = N_BSSADDR(*execp);

  /* The file offsets of the sections */
  obj_textsec (abfd)->filepos = N_TXTOFF(*execp);
  obj_datasec (abfd)->filepos = N_DATOFF(*execp);

  /* The file offsets of the relocation info */
  obj_textsec (abfd)->rel_filepos = N_TRELOFF(*execp);
  obj_datasec (abfd)->rel_filepos = N_DRELOFF(*execp);

  /* The file offsets of the string table and symbol table.  */
  obj_str_filepos (abfd) = N_STROFF (*execp);
  obj_sym_filepos (abfd) = N_SYMOFF (*execp);

  /* Determine the architecture and machine type of the object file.  */
  switch (N_MACHTYPE (*exec_hdr (abfd))) {
  default:
    abfd->obj_arch = bfd_arch_obscure;
    break;
  }

  adata(abfd)->page_size = PAGE_SIZE;
  adata(abfd)->segment_size = SEGMENT_SIZE;
  adata(abfd)->exec_bytes_size = EXEC_BYTES_SIZE;

  return abfd->xvec;

  /* The architecture is encoded in various ways in various a.out variants,
     or is not encoded at all in some of them.  The relocation size depends
     on the architecture and the a.out variant.  Finally, the return value
     is the bfd_target vector in use.  If an error occurs, return zero and
     set bfd_error to the appropriate error code.
     
     Formats such as b.out, which have additional fields in the a.out
     header, should cope with them in this callback as well.  */
#endif				/* DOCUMENTATION */

  result = (*callback_to_real_object_p)(abfd);

  /* Now that the segment addresses have been worked out, take a better
     guess at whether the file is executable.  If the entry point
     is within the text segment, assume it is.  (This makes files
     executable even if their entry point address is 0, as long as
     their text starts at zero.)  

     At some point we should probably break down and stat the file and
     declare it executable if (one of) its 'x' bits are on...  */
  if ((execp->a_entry >= obj_textsec(abfd)->vma) &&
      (execp->a_entry < obj_textsec(abfd)->vma + obj_textsec(abfd)->_raw_size))
    abfd->flags |= EXEC_P;
  if (result)
    {
      abfd->sections = obj_textsec (abfd);
      obj_textsec (abfd)->next = obj_datasec (abfd);
      obj_datasec (abfd)->next = obj_bsssec (abfd);
    }
  else
    {
      free (rawptr);
      abfd->tdata.aout_data = oldrawptr;
    }
  return result;
}

/*
FUNCTION
	aout_<size>_mkobject

DESCRIPTION
	This routine initializes a BFD for use with a.out files.

EXAMPLE
	boolean aout_<size>_mkobject, (bfd *);
*/

boolean
DEFUN(NAME(aout,mkobject),(abfd),
     bfd *abfd)
{
  struct aout_data_struct  *rawptr;

  bfd_error = system_call_error;

  /* Use an intermediate variable for clarity */
  rawptr = (struct aout_data_struct  *)bfd_zalloc (abfd, sizeof (struct aout_data_struct ));
  
  if (rawptr == NULL) {
    bfd_error = no_memory;
    return false;
  }
  
  abfd->tdata.aout_data = rawptr;
  exec_hdr (abfd) = &(rawptr->e);
  
  /* For simplicity's sake we just make all the sections right here. */
  
  obj_textsec (abfd) = (asection *)NULL;
  obj_datasec (abfd) = (asection *)NULL;
  obj_bsssec (abfd) = (asection *)NULL;
  bfd_make_section (abfd, ".text");
  bfd_make_section (abfd, ".data");
  bfd_make_section (abfd, ".bss");
  bfd_make_section (abfd, BFD_ABS_SECTION_NAME);
  bfd_make_section (abfd, BFD_UND_SECTION_NAME);
  bfd_make_section (abfd, BFD_COM_SECTION_NAME);
  
  return true;
}


/*
FUNCTION
	aout_<size>_machine_type

DESCRIPTION
	Keep track of machine architecture and machine type for
	a.out's. Return the machine_type for a particular
	arch&machine, or M_UNKNOWN if that exact arch&machine can't be
	represented in a.out format. 

	If the architecture is understood, machine type 0 (default)
	should always be understood.  

EXAMPLE
	enum machine_type  aout_<size>_machine_type
	 (enum bfd_architecture arch,
	  unsigned long machine));
*/

enum machine_type
DEFUN(NAME(aout,machine_type),(arch, machine),
      enum bfd_architecture arch AND
      unsigned long machine)
{
  enum machine_type arch_flags;
    
  arch_flags = M_UNKNOWN;
    
  switch (arch) {
  case bfd_arch_sparc:
    if (machine == 0)	arch_flags = M_SPARC;
    break;
      
  case bfd_arch_m68k:
    switch (machine) {
    case 0:		arch_flags = M_68010; break;
    case 68000:		arch_flags = M_UNKNOWN;	break;
    case 68010:		arch_flags = M_68010; break;
    case 68020:		arch_flags = M_68020; break;
    default:		arch_flags = M_UNKNOWN; break;
    }
    break;
      
  case bfd_arch_i386:
    if (machine == 0)	arch_flags = M_386;
    break;
      
  case bfd_arch_a29k:
    if (machine == 0)	arch_flags = M_29K;
    break;
      
  default:
    arch_flags = M_UNKNOWN;
    break;
  }
  return arch_flags;
}


/*
FUNCTION
	aout_<size>_set_arch_mach

DESCRIPTION
	Sets the architecture and the machine of the BFD to those
	values supplied. Verifies that the format can support the
	architecture required.

EXAMPLE
	boolean aout_<size>_set_arch_mach,
	 (bfd *,
	  enum bfd_architecture,
	  unsigned long machine));
*/

boolean
DEFUN(NAME(aout,set_arch_mach),(abfd, arch, machine),
      bfd *abfd AND
      enum bfd_architecture arch AND
      unsigned long machine)
{
  bfd_default_set_arch_mach(abfd, arch, machine);
  if (arch != bfd_arch_unknown &&
      NAME(aout,machine_type) (arch, machine) == M_UNKNOWN)
    return false;		/* We can't represent this type */

  /* Determine the size of a relocation entry */
  switch (arch) {
  case bfd_arch_sparc:
  case bfd_arch_a29k:
    obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
    break;
  default:
    obj_reloc_entry_size (abfd) = RELOC_STD_SIZE;
    break;
  }

  return (*aout_backend_info(abfd)->set_sizes) (abfd);
}

boolean
DEFUN (NAME (aout,adjust_sizes_and_vmas), (abfd, text_size, text_end),
       bfd *abfd AND bfd_size_type *text_size AND file_ptr *text_end)
{
  struct internal_exec *execp = exec_hdr (abfd);
  if ((obj_textsec (abfd) == NULL) || (obj_datasec (abfd) == NULL)) 
    {
      bfd_error = invalid_operation;
      return false;
    }
  if (adata(abfd).magic != undecided_magic) return true;
  obj_textsec(abfd)->_raw_size = 	      
    align_power(obj_textsec(abfd)->_raw_size,
		obj_textsec(abfd)->alignment_power);

  *text_size = obj_textsec (abfd)->_raw_size;
  /* Rule (heuristic) for when to pad to a new page.  Note that there
   * are (at least) two ways demand-paged (ZMAGIC) files have been
   * handled.  Most Berkeley-based systems start the text segment at
   * (PAGE_SIZE).  However, newer versions of SUNOS start the text
   * segment right after the exec header; the latter is counted in the
   * text segment size, and is paged in by the kernel with the rest of
   * the text. */

  /* This perhaps isn't the right way to do this, but made it simpler for me
     to understand enough to implement it.  Better would probably be to go
     right from BFD flags to alignment/positioning characteristics.  But the
     old code was sloppy enough about handling the flags, and had enough
     other magic, that it was a little hard for me to understand.  I think
     I understand it better now, but I haven't time to do the cleanup this
     minute.  */
  if (adata(abfd).magic == undecided_magic)
    {
      if (abfd->flags & D_PAGED)
	/* whether or not WP_TEXT is set */
	adata(abfd).magic = z_magic;
      else if (abfd->flags & WP_TEXT)
	adata(abfd).magic = n_magic;
      else
	adata(abfd).magic = o_magic;
    }

#ifdef BFD_AOUT_DEBUG /* requires gcc2 */
#if __GNUC__ >= 2
  fprintf (stderr, "%s text=<%x,%x,%x> data=<%x,%x,%x> bss=<%x,%x,%x>\n",
	   ({ char *str;
	      switch (adata(abfd).magic) {
	      case n_magic: str = "NMAGIC"; break;
	      case o_magic: str = "OMAGIC"; break;
	      case z_magic: str = "ZMAGIC"; break;
	      default: abort ();
	      }
	      str;
	    }),
	   obj_textsec(abfd)->vma, obj_textsec(abfd)->_raw_size, obj_textsec(abfd)->alignment_power,
	   obj_datasec(abfd)->vma, obj_datasec(abfd)->_raw_size, obj_datasec(abfd)->alignment_power,
	   obj_bsssec(abfd)->vma, obj_bsssec(abfd)->_raw_size, obj_bsssec(abfd)->alignment_power);
#endif
#endif

  switch (adata(abfd).magic)
    {
    case o_magic:
      {
	file_ptr pos = adata (abfd).exec_bytes_size;
	bfd_vma vma = 0;
	int pad = 0;

	obj_textsec(abfd)->filepos = pos;
	pos += obj_textsec(abfd)->_raw_size;
	vma += obj_textsec(abfd)->_raw_size;
	if (!obj_datasec(abfd)->user_set_vma)
	  {
#if 0	    /* ?? Does alignment in the file image really matter? */
	    pad = align_power (vma, obj_datasec(abfd)->alignment_power) - vma;
#endif
	    obj_textsec(abfd)->_raw_size += pad;
	    pos += pad;
	    vma += pad;
	    obj_datasec(abfd)->vma = vma;
	  }
	obj_datasec(abfd)->filepos = pos;
	pos += obj_datasec(abfd)->_raw_size;
	vma += obj_datasec(abfd)->_raw_size;
	if (!obj_bsssec(abfd)->user_set_vma)
	  {
#if 0
	    pad = align_power (vma, obj_bsssec(abfd)->alignment_power) - vma;
#endif
	    obj_datasec(abfd)->_raw_size += pad;
	    pos += pad;
	    vma += pad;
	    obj_bsssec(abfd)->vma = vma;
	  }
	obj_bsssec(abfd)->filepos = pos;
	execp->a_text = obj_textsec(abfd)->_raw_size;
	execp->a_data = obj_datasec(abfd)->_raw_size;
	execp->a_bss = obj_bsssec(abfd)->_raw_size;
	N_SET_MAGIC (*execp, OMAGIC);
      }
      break;
    case z_magic:
      {
	bfd_size_type data_pad, text_pad;
	file_ptr text_end;
	CONST struct aout_backend_data *abdp;
	int ztih;
	bfd_vma data_vma;

	abdp = aout_backend_info (abfd);
	ztih = abdp && abdp->text_includes_header;
	obj_textsec(abfd)->filepos = (ztih
				      ? adata(abfd).exec_bytes_size
				      : adata(abfd).page_size);
	if (! obj_textsec(abfd)->user_set_vma)
	  /* ?? Do we really need to check for relocs here?  */
	  obj_textsec(abfd)->vma = ((abfd->flags & HAS_RELOC)
				    ? 0
				    : (ztih
				       ? (abdp->default_text_vma
					  + adata(abfd).exec_bytes_size)
				       : abdp->default_text_vma));
	/* Could take strange alignment of text section into account here?  */

	/* Find start of data.  */
	text_end = obj_textsec(abfd)->filepos + obj_textsec(abfd)->_raw_size;
	text_pad = BFD_ALIGN (text_end, adata(abfd).page_size) - text_end;
	obj_textsec(abfd)->_raw_size += text_pad;
	text_end += text_pad;

	if (!obj_datasec(abfd)->user_set_vma)
	  {
	    bfd_vma vma;
	    vma = obj_textsec(abfd)->vma + obj_textsec(abfd)->_raw_size;
	    obj_datasec(abfd)->vma = BFD_ALIGN (vma, adata(abfd).segment_size);
	  }
	data_vma = obj_datasec(abfd)->vma;
	if (abdp && abdp->zmagic_mapped_contiguous)
	  {
	    text_pad = (obj_datasec(abfd)->vma
			- obj_textsec(abfd)->vma
			- obj_textsec(abfd)->_raw_size);
	    obj_textsec(abfd)->_raw_size += text_pad;
	  }
	obj_datasec(abfd)->filepos = (obj_textsec(abfd)->filepos
				      + obj_textsec(abfd)->_raw_size);

	/* Fix up exec header while we're at it.  */
	execp->a_text = obj_textsec(abfd)->_raw_size;
	if (ztih && (!abdp || (abdp && !abdp->exec_header_not_counted)))
	  execp->a_text += adata(abfd).exec_bytes_size;
	N_SET_MAGIC (*execp, ZMAGIC);
	/* Spec says data section should be rounded up to page boundary.  */
	/* If extra space in page is left after data section, fudge data
	   in the header so that the bss section looks smaller by that
	   amount.  We'll start the bss section there, and lie to the OS.  */
	obj_datasec(abfd)->_raw_size
	  = align_power (obj_datasec(abfd)->_raw_size,
			 obj_bsssec(abfd)->alignment_power);
	execp->a_data = BFD_ALIGN (obj_datasec(abfd)->_raw_size,
				   adata(abfd).page_size);
	data_pad = execp->a_data - obj_datasec(abfd)->_raw_size;
	/* This code is almost surely botched.  It'll only get tested
	   for the case where the application does explicitly set the VMA
	   of the BSS section.  */
	if (obj_bsssec(abfd)->user_set_vma
	    && (obj_bsssec(abfd)->vma
		> BFD_ALIGN (obj_datasec(abfd)->vma
			     + obj_datasec(abfd)->_raw_size,
			     adata(abfd).page_size)))
	  {
	    /* Can't play with squeezing into data pages; fix this code.  */
	    abort ();
	  }
	if (!obj_bsssec(abfd)->user_set_vma)
	  obj_bsssec(abfd)->vma = (obj_datasec(abfd)->vma
				   + obj_datasec(abfd)->_raw_size);
	if (data_pad > obj_bsssec(abfd)->_raw_size)
	  execp->a_bss = 0;
	else
	  execp->a_bss = obj_bsssec(abfd)->_raw_size - data_pad;
      }
      break;
    case n_magic:
      {
	file_ptr pos = adata(abfd).exec_bytes_size;
	bfd_vma vma = 0;
	int pad;

	obj_textsec(abfd)->filepos = pos;
	if (!obj_textsec(abfd)->user_set_vma)
	  obj_textsec(abfd)->vma = vma;
	else
	  vma = obj_textsec(abfd)->vma;
	pos += obj_textsec(abfd)->_raw_size;
	vma += obj_textsec(abfd)->_raw_size;
	obj_datasec(abfd)->filepos = pos;
	if (!obj_datasec(abfd)->user_set_vma)
	  obj_datasec(abfd)->vma = BFD_ALIGN (vma, adata(abfd).segment_size);
	vma = obj_datasec(abfd)->vma;

	/* Since BSS follows data immediately, see if it needs alignment.  */
	vma += obj_datasec(abfd)->_raw_size;
	pad = align_power (vma, obj_bsssec(abfd)->alignment_power) - vma;
	obj_datasec(abfd)->_raw_size += pad;
	pos += obj_datasec(abfd)->_raw_size;

	if (!obj_bsssec(abfd)->user_set_vma)