[deliverable/binutils-gdb.git] / bfd / format.c

/* Generic BFD support for file formats.
   Copyright (C) 1990, 91, 92, 93, 94, 95, 1999 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/*
SECTION
	File formats

	A format is a BFD concept of high level file contents type. The
	formats supported by BFD are:

	o <<bfd_object>>

	The BFD may contain data, symbols, relocations and debug info.

	o <<bfd_archive>>

	The BFD contains other BFDs and an optional index.

	o <<bfd_core>>

	The BFD contains the result of an executable core dump.

*/

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"

/* IMPORT from targets.c.  */
extern const size_t _bfd_target_vector_entries;

/*
FUNCTION
	bfd_check_format

SYNOPSIS
	boolean bfd_check_format(bfd *abfd, bfd_format format);

DESCRIPTION
	Verify if the file attached to the BFD @var{abfd} is compatible
	with the format @var{format} (i.e., one of <<bfd_object>>,
	<<bfd_archive>> or <<bfd_core>>).

	If the BFD has been set to a specific target before the
	call, only the named target and format combination is
	checked. If the target has not been set, or has been set to
	<<default>>, then all the known target backends is
	interrogated to determine a match.  If the default target
	matches, it is used.  If not, exactly one target must recognize
	the file, or an error results.

	The function returns <<true>> on success, otherwise <<false>>
	with one of the following error codes:

	o <<bfd_error_invalid_operation>> -
	if <<format>> is not one of <<bfd_object>>, <<bfd_archive>> or
	<<bfd_core>>.

	o <<bfd_error_system_call>> -
	if an error occured during a read - even some file mismatches
	can cause bfd_error_system_calls.

	o <<file_not_recognised>> -
	none of the backends recognised the file format.

	o <<bfd_error_file_ambiguously_recognized>> -
	more than one backend recognised the file format.
*/

boolean
bfd_check_format (abfd, format)
     bfd *abfd;
     bfd_format format;
{
  return bfd_check_format_matches (abfd, format, NULL);
}

/*
FUNCTION
	bfd_check_format_matches

SYNOPSIS
	boolean bfd_check_format_matches(bfd *abfd, bfd_format format, char ***matching);

DESCRIPTION
	Like <<bfd_check_format>>, except when it returns false with
	<<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>.  In that
	case, if @var{matching} is not NULL, it will be filled in with
	a NULL-terminated list of the names of the formats that matched,
	allocated with <<malloc>>.
	Then the user may choose a format and try again.

	When done with the list that @var{matching} points to, the caller
	should free it.
*/

boolean
bfd_check_format_matches (abfd, format, matching)
     bfd *abfd;
     bfd_format format;
     char ***matching;
{
  extern const bfd_target binary_vec;
  const bfd_target * const *target, *save_targ, *right_targ;
  char **matching_vector = NULL;
  int match_count;

  if (!bfd_read_p (abfd) ||
      ((int)(abfd->format) < (int)bfd_unknown) ||
      ((int)(abfd->format) >= (int)bfd_type_end))
    {
      bfd_set_error (bfd_error_invalid_operation);
      return false;
    }

  if (abfd->format != bfd_unknown)
    return (abfd->format == format)? true: false;

  /* Since the target type was defaulted, check them
     all in the hope that one will be uniquely recognized.  */
  save_targ = abfd->xvec;
  match_count = 0;

  if (matching)
    {
      matching_vector =
	(char **) bfd_malloc (sizeof (char *) *
			      (_bfd_target_vector_entries + 1));
      if (!matching_vector)
	return false;
      matching_vector[0] = NULL;
      *matching = matching_vector;
    }

  right_targ = 0;

  /* Presume the answer is yes.  */
  abfd->format = format;

  /* If the target type was explicitly specified, just check that target.  */
  if (!abfd->target_defaulted)
    {
      if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0)	/* rewind! */
	return false;

      right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));

      if (right_targ)
	{
	  abfd->xvec = right_targ;	/* Set the target as returned.  */

	  if (matching)
	    free (matching_vector);

	  return true;			/* File position has moved, BTW.  */
	}

      /* For a long time the code has dropped through to check all
	 targets if the specified target was wrong.  I don't know why,
	 and I'm reluctant to change it.  However, in the case of an
	 archive, it can cause problems.  If the specified target does
	 not permit archives (e.g., the binary target), then we should
	 not allow some other target to recognize it as an archive, but
	 should instead allow the specified target to recognize it as an
	 object.  When I first made this change, it broke the PE target,
	 because the specified pei-i386 target did not recognize the
	 actual pe-i386 archive.  Since there may be other problems of
	 this sort, I changed this test to check only for the binary
	 target.  */
      if (format == bfd_archive && save_targ == &binary_vec)
	{
	  abfd->xvec = save_targ;
	  abfd->format = bfd_unknown;

	  if (matching)
	    free (matching_vector);

	  bfd_set_error (bfd_error_file_not_recognized);

	  return false;
	}
    }

  for (target = bfd_target_vector; *target != NULL; target++)
    {
      const bfd_target *temp;

      if (*target == &binary_vec)
	continue;

      abfd->xvec = *target;	/* Change BFD's target temporarily */

      if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0)
	return false;

      /* If _bfd_check_format neglects to set bfd_error, assume
	 bfd_error_wrong_format.  We didn't used to even pay any
	 attention to bfd_error, so I suspect that some
	 _bfd_check_format might have this problem.  */
      bfd_set_error (bfd_error_wrong_format);

      temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));

      if (temp)
	{		/* This format checks out as ok!  */
	  right_targ = temp;

	  if (matching)
	    {
	      matching_vector[match_count] = temp->name;
	      matching_vector[match_count + 1] = NULL;
	    }

	  match_count++;

	  /* If this is the default target, accept it, even if other
	     targets might match.  People who want those other targets
	     have to set the GNUTARGET variable.  */
	  if (temp == bfd_default_vector[0])
	    {
	      if (matching)
		{
		  matching_vector[0] = temp->name;
		  matching_vector[1] = NULL;
		}
	      match_count = 1;
	      break;
	    }
#ifdef GNU960
	  /* Big- and little-endian b.out archives look the same, but it
	     doesn't matter: there is no difference in their headers, and
	     member file byte orders will (I hope) be handled appropriately
	     by bfd.  Ditto for big and little coff archives.  And the 4
	     coff/b.out object formats are unambiguous.  So accept the
	     first match we find.  */
	  break;
#endif
	}
      else if (bfd_get_error () != bfd_error_wrong_format)
	{
	  abfd->xvec = save_targ;
	  abfd->format = bfd_unknown;

	  if (matching && bfd_get_error ()
	      != bfd_error_file_ambiguously_recognized)
	    free (matching_vector);

	  return false;
	}
    }

  if (match_count == 1)
    {
      abfd->xvec = right_targ;		/* Change BFD's target permanently.  */

      if (matching)
	free (matching_vector);

      return true;			/* File position has moved, BTW.  */
    }

  abfd->xvec = save_targ;		/* Restore original target type.  */
  abfd->format = bfd_unknown;		/* Restore original format.  */

  if (match_count == 0)
    {
      bfd_set_error (bfd_error_file_not_recognized);

      if (matching)
	free (matching_vector);
    }
  else
    bfd_set_error (bfd_error_file_ambiguously_recognized);

  return false;
}

/*
FUNCTION
	bfd_set_format

SYNOPSIS
	boolean bfd_set_format(bfd *abfd, bfd_format format);

DESCRIPTION
	This function sets the file format of the BFD @var{abfd} to the
	format @var{format}. If the target set in the BFD does not
	support the format requested, the format is invalid, or the BFD
	is not open for writing, then an error occurs.
*/

boolean
bfd_set_format (abfd, format)
     bfd *abfd;
     bfd_format format;
{
  if (bfd_read_p (abfd) ||
      ((int)abfd->format < (int)bfd_unknown) ||
      ((int)abfd->format >= (int)bfd_type_end))
    {
      bfd_set_error (bfd_error_invalid_operation);
      return false;
    }

  if (abfd->format != bfd_unknown)
    return (abfd->format == format) ? true : false;

  /* Presume the answer is yes.  */
  abfd->format = format;

  if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd)))
    {
      abfd->format = bfd_unknown;
      return false;
    }

  return true;
}

/*
FUNCTION
	bfd_format_string

SYNOPSIS
	CONST char *bfd_format_string(bfd_format format);

DESCRIPTION
	Return a pointer to a const string
	<<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
	depending upon the value of @var{format}.
*/

CONST char *
bfd_format_string (format)
     bfd_format format;
{
  if (((int)format <(int) bfd_unknown)
      || ((int)format >=(int) bfd_type_end))
    return "invalid";

  switch (format)
    {
    case bfd_object:
      return "object";		/* Linker/assember/compiler output.  */
    case bfd_archive:
      return "archive";		/* Object archive file.  */
    case bfd_core:
      return "core";		/* Core dump.  */
    default:
      return "unknown";
    }
}
Commit	Line	Data
252b5132 RH	1	/* Generic BFD support for file formats.
	2	Copyright (C) 1990, 91, 92, 93, 94, 95, 1999 Free Software Foundation, Inc.
	3	Written by Cygnus Support.
	4
	5	This file is part of BFD, the Binary File Descriptor library.
	6
	7	This program is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 2 of the License, or
	10	(at your option) any later version.
	11
	12	This program is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with this program; if not, write to the Free Software
	19	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
	20
	21	/*
	22	SECTION
	23	File formats
	24
	25	A format is a BFD concept of high level file contents type. The
3fde5a36	26	formats supported by BFD are:
252b5132 RH	27
	28	o <<bfd_object>>
	29
	30	The BFD may contain data, symbols, relocations and debug info.
	31
	32	o <<bfd_archive>>
	33
	34	The BFD contains other BFDs and an optional index.
	35
	36	o <<bfd_core>>
	37
	38	The BFD contains the result of an executable core dump.
	39
252b5132 RH	40	*/
	41
	42	#include "bfd.h"
	43	#include "sysdep.h"
	44	#include "libbfd.h"
	45
	46	/* IMPORT from targets.c. */
	47	extern const size_t _bfd_target_vector_entries;
	48
	49	/*
	50	FUNCTION
	51	bfd_check_format
	52
	53	SYNOPSIS
	54	boolean bfd_check_format(bfd *abfd, bfd_format format);
	55
	56	DESCRIPTION
	57	Verify if the file attached to the BFD @var{abfd} is compatible
	58	with the format @var{format} (i.e., one of <<bfd_object>>,
	59	<<bfd_archive>> or <<bfd_core>>).
	60
	61	If the BFD has been set to a specific target before the
	62	call, only the named target and format combination is
	63	checked. If the target has not been set, or has been set to
	64	<<default>>, then all the known target backends is
	65	interrogated to determine a match. If the default target
	66	matches, it is used. If not, exactly one target must recognize
	67	the file, or an error results.
	68
	69	The function returns <<true>> on success, otherwise <<false>>
3fde5a36	70	with one of the following error codes:
252b5132 RH	71
	72	o <<bfd_error_invalid_operation>> -
	73	if <<format>> is not one of <<bfd_object>>, <<bfd_archive>> or
	74	<<bfd_core>>.
	75
	76	o <<bfd_error_system_call>> -
	77	if an error occured during a read - even some file mismatches
	78	can cause bfd_error_system_calls.
	79
	80	o <<file_not_recognised>> -
	81	none of the backends recognised the file format.
	82
	83	o <<bfd_error_file_ambiguously_recognized>> -
	84	more than one backend recognised the file format.
	85	*/
	86
	87	boolean
	88	bfd_check_format (abfd, format)
	89	bfd *abfd;
	90	bfd_format format;
	91	{
	92	return bfd_check_format_matches (abfd, format, NULL);
	93	}
	94
	95	/*
	96	FUNCTION
	97	bfd_check_format_matches
	98
	99	SYNOPSIS
	100	boolean bfd_check_format_matches(bfd abfd, bfd_format format, char **matching);
	101
	102	DESCRIPTION
	103	Like <<bfd_check_format>>, except when it returns false with
	104	<<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>. In that
	105	case, if @var{matching} is not NULL, it will be filled in with
	106	a NULL-terminated list of the names of the formats that matched,
	107	allocated with <<malloc>>.
	108	Then the user may choose a format and try again.
	109
	110	When done with the list that @var{matching} points to, the caller
3fde5a36	111	should free it.
252b5132 RH	112	*/
	113
	114	boolean
	115	bfd_check_format_matches (abfd, format, matching)
	116	bfd *abfd;
	117	bfd_format format;
	118	char ***matching;
	119	{
	120	extern const bfd_target binary_vec;
	121	const bfd_target * const target, save_targ, *right_targ;
	122	char **matching_vector = NULL;
	123	int match_count;
	124
	125	if (!bfd_read_p (abfd) \|\|
	126	((int)(abfd->format) < (int)bfd_unknown) \|\|
1d713d9e NC	127	((int)(abfd->format) >= (int)bfd_type_end))
	128	{
	129	bfd_set_error (bfd_error_invalid_operation);
	130	return false;
	131	}
252b5132 RH	132
	133	if (abfd->format != bfd_unknown)
	134	return (abfd->format == format)? true: false;
	135
3fde5a36	136	/* Since the target type was defaulted, check them
252b5132	137	all in the hope that one will be uniquely recognized. */
252b5132 RH	138	save_targ = abfd->xvec;
252b5132 RH	139	match_count = 0;
3fde5a36	140
252b5132 RH	141	if (matching)
	142	{
	143	matching_vector =
	144	(char *) bfd_malloc (sizeof (char ) *
	145	(_bfd_target_vector_entries + 1));
	146	if (!matching_vector)
	147	return false;
	148	matching_vector[0] = NULL;
	149	*matching = matching_vector;
	150	}
3fde5a36	151
252b5132 RH	152	right_targ = 0;
252b5132 RH	153
1d713d9e	154	/* Presume the answer is yes. */
252b5132 RH	155	abfd->format = format;
	156
	157	/* If the target type was explicitly specified, just check that target. */
1d713d9e NC	158	if (!abfd->target_defaulted)
	159	{
	160	if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0) /* rewind! */
252b5132	161	return false;
3fde5a36	162
1d713d9e	163	right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
3fde5a36	164
1d713d9e	165	if (right_targ)
252b5132	166	{
1d713d9e	167	abfd->xvec = right_targ; /* Set the target as returned. */
3fde5a36	168
1d713d9e NC	169	if (matching)
1d713d9e NC	170	free (matching_vector);
3fde5a36	171
1d713d9e	172	return true; /* File position has moved, BTW. */
252b5132	173	}
1d713d9e NC	174
	175	/* For a long time the code has dropped through to check all
	176	targets if the specified target was wrong. I don't know why,
	177	and I'm reluctant to change it. However, in the case of an
	178	archive, it can cause problems. If the specified target does
	179	not permit archives (e.g., the binary target), then we should
	180	not allow some other target to recognize it as an archive, but
	181	should instead allow the specified target to recognize it as an
	182	object. When I first made this change, it broke the PE target,
	183	because the specified pei-i386 target did not recognize the
	184	actual pe-i386 archive. Since there may be other problems of
	185	this sort, I changed this test to check only for the binary
	186	target. */
	187	if (format == bfd_archive && save_targ == &binary_vec)
252b5132	188	{
1d713d9e NC	189	abfd->xvec = save_targ;
1d713d9e NC	190	abfd->format = bfd_unknown;
3fde5a36	191
1d713d9e NC	192	if (matching)
1d713d9e NC	193	free (matching_vector);
3fde5a36	194
1d713d9e	195	bfd_set_error (bfd_error_file_not_recognized);
3fde5a36	196
1d713d9e NC	197	return false;
	198	}
	199	}
	200
	201	for (target = bfd_target_vector; *target != NULL; target++)
	202	{
	203	const bfd_target *temp;
3fde5a36	204
1d713d9e NC	205	if (*target == &binary_vec)
1d713d9e NC	206	continue;
3fde5a36	207
1d713d9e	208	abfd->xvec = target; / Change BFD's target temporarily */
3fde5a36	209
1d713d9e NC	210	if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0)
1d713d9e NC	211	return false;
3fde5a36	212
1d713d9e NC	213	/* If _bfd_check_format neglects to set bfd_error, assume
	214	bfd_error_wrong_format. We didn't used to even pay any
	215	attention to bfd_error, so I suspect that some
	216	_bfd_check_format might have this problem. */
	217	bfd_set_error (bfd_error_wrong_format);
	218
	219	temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
3fde5a36	220
1d713d9e NC	221	if (temp)
	222	{ /* This format checks out as ok! */
	223	right_targ = temp;
3fde5a36	224
252b5132 RH	225	if (matching)
252b5132 RH	226	{
1d713d9e NC	227	matching_vector[match_count] = temp->name;
	228	matching_vector[match_count + 1] = NULL;
	229	}
3fde5a36	230
1d713d9e	231	match_count++;
3fde5a36	232
1d713d9e NC	233	/* If this is the default target, accept it, even if other
	234	targets might match. People who want those other targets
	235	have to set the GNUTARGET variable. */
	236	if (temp == bfd_default_vector[0])
	237	{
	238	if (matching)
	239	{
	240	matching_vector[0] = temp->name;
	241	matching_vector[1] = NULL;
	242	}
	243	match_count = 1;
	244	break;
252b5132	245	}
252b5132	246	#ifdef GNU960
1d713d9e NC	247	/* Big- and little-endian b.out archives look the same, but it
	248	doesn't matter: there is no difference in their headers, and
	249	member file byte orders will (I hope) be handled appropriately
	250	by bfd. Ditto for big and little coff archives. And the 4
	251	coff/b.out object formats are unambiguous. So accept the
	252	first match we find. */
	253	break;
252b5132	254	#endif
1d713d9e NC	255	}
	256	else if (bfd_get_error () != bfd_error_wrong_format)
	257	{
	258	abfd->xvec = save_targ;
	259	abfd->format = bfd_unknown;
3fde5a36	260
1d713d9e NC	261	if (matching && bfd_get_error ()
	262	!= bfd_error_file_ambiguously_recognized)
	263	free (matching_vector);
3fde5a36	264
1d713d9e NC	265	return false;
	266	}
	267	}
3fde5a36	268
1d713d9e NC	269	if (match_count == 1)
	270	{
	271	abfd->xvec = right_targ; /* Change BFD's target permanently. */
3fde5a36	272
1d713d9e	273	if (matching)
252b5132	274	free (matching_vector);
3fde5a36	275
1d713d9e	276	return true; /* File position has moved, BTW. */
252b5132	277	}
252b5132	278
1d713d9e NC	279	abfd->xvec = save_targ; /* Restore original target type. */
1d713d9e NC	280	abfd->format = bfd_unknown; /* Restore original format. */
3fde5a36	281
252b5132 RH	282	if (match_count == 0)
	283	{
	284	bfd_set_error (bfd_error_file_not_recognized);
3fde5a36	285
252b5132 RH	286	if (matching)
	287	free (matching_vector);
	288	}
	289	else
	290	bfd_set_error (bfd_error_file_ambiguously_recognized);
3fde5a36	291
252b5132 RH	292	return false;
	293	}
	294
	295	/*
	296	FUNCTION
	297	bfd_set_format
	298
	299	SYNOPSIS
	300	boolean bfd_set_format(bfd *abfd, bfd_format format);
	301
	302	DESCRIPTION
	303	This function sets the file format of the BFD @var{abfd} to the
	304	format @var{format}. If the target set in the BFD does not
	305	support the format requested, the format is invalid, or the BFD
	306	is not open for writing, then an error occurs.
252b5132 RH	307	*/
	308
	309	boolean
	310	bfd_set_format (abfd, format)
	311	bfd *abfd;
	312	bfd_format format;
	313	{
252b5132 RH	314	if (bfd_read_p (abfd) \|\|
252b5132 RH	315	((int)abfd->format < (int)bfd_unknown) \|\|
1d713d9e NC	316	((int)abfd->format >= (int)bfd_type_end))
	317	{
	318	bfd_set_error (bfd_error_invalid_operation);
	319	return false;
	320	}
252b5132 RH	321
252b5132 RH	322	if (abfd->format != bfd_unknown)
1d713d9e	323	return (abfd->format == format) ? true : false;
252b5132	324
1d713d9e	325	/* Presume the answer is yes. */
252b5132 RH	326	abfd->format = format;
252b5132 RH	327
1d713d9e NC	328	if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd)))
	329	{
	330	abfd->format = bfd_unknown;
	331	return false;
	332	}
252b5132 RH	333
	334	return true;
	335	}
	336
252b5132 RH	337	/*
	338	FUNCTION
	339	bfd_format_string
	340
	341	SYNOPSIS
	342	CONST char *bfd_format_string(bfd_format format);
	343
	344	DESCRIPTION
	345	Return a pointer to a const string
	346	<<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
	347	depending upon the value of @var{format}.
	348	*/
	349
	350	CONST char *
	351	bfd_format_string (format)
	352	bfd_format format;
	353	{
3fde5a36 KH	354	if (((int)format <(int) bfd_unknown)
3fde5a36 KH	355	\|\| ((int)format >=(int) bfd_type_end))
252b5132	356	return "invalid";
3fde5a36	357
1d713d9e NC	358	switch (format)
	359	{
	360	case bfd_object:
	361	return "object"; /* Linker/assember/compiler output. */
3fde5a36	362	case bfd_archive:
1d713d9e	363	return "archive"; /* Object archive file. */
3fde5a36	364	case bfd_core:
1d713d9e	365	return "core"; /* Core dump. */
3fde5a36	366	default:
1d713d9e NC	367	return "unknown";
1d713d9e NC	368	}
252b5132	369	}