[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
	26	formats supported by BFD are:
	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
	40
	41	*/
	42
	43	#include "bfd.h"
	44	#include "sysdep.h"
	45	#include "libbfd.h"
	46
	47	/* IMPORT from targets.c. */
	48	extern const size_t _bfd_target_vector_entries;
	49
	50	/*
	51	FUNCTION
	52	bfd_check_format
	53
	54	SYNOPSIS
	55	boolean bfd_check_format(bfd *abfd, bfd_format format);
	56
	57	DESCRIPTION
	58	Verify if the file attached to the BFD @var{abfd} is compatible
	59	with the format @var{format} (i.e., one of <<bfd_object>>,
	60	<<bfd_archive>> or <<bfd_core>>).
	61
	62	If the BFD has been set to a specific target before the
	63	call, only the named target and format combination is
	64	checked. If the target has not been set, or has been set to
65	<<default>>, then all the known target backends is
66	interrogated to determine a match. If the default target
67	matches, it is used. If not, exactly one target must recognize
68	the file, or an error results.
69
70	The function returns <<true>> on success, otherwise <<false>>
71	with one of the following error codes:
72
73	o <<bfd_error_invalid_operation>> -
74	if <<format>> is not one of <<bfd_object>>, <<bfd_archive>> or
75	<<bfd_core>>.
76
77	o <<bfd_error_system_call>> -
78	if an error occured during a read - even some file mismatches
79	can cause bfd_error_system_calls.
80
81	o <<file_not_recognised>> -
82	none of the backends recognised the file format.
83
84	o <<bfd_error_file_ambiguously_recognized>> -
85	more than one backend recognised the file format.
86	*/
87
88	boolean
89	bfd_check_format (abfd, format)
90	bfd *abfd;
91	bfd_format format;
92	{
93	return bfd_check_format_matches (abfd, format, NULL);
94	}
95
96	/*
97	FUNCTION
98	bfd_check_format_matches
99
100	SYNOPSIS
101	boolean bfd_check_format_matches(bfd abfd, bfd_format format, char **matching);
102
103	DESCRIPTION
104	Like <<bfd_check_format>>, except when it returns false with
105	<<bfd_errno>> set to <<bfd_error_file_ambiguously_recognized>>. In that
106	case, if @var{matching} is not NULL, it will be filled in with
107	a NULL-terminated list of the names of the formats that matched,
108	allocated with <<malloc>>.
109	Then the user may choose a format and try again.
110
111	When done with the list that @var{matching} points to, the caller
112	should free it.
113	*/
114
115	boolean
116	bfd_check_format_matches (abfd, format, matching)
117	bfd *abfd;
118	bfd_format format;
119	char ***matching;
120	{
121	extern const bfd_target binary_vec;
122	const bfd_target * const target, save_targ, *right_targ;
123	char **matching_vector = NULL;
124	int match_count;
125
126	if (!bfd_read_p (abfd) \|\|
127	((int)(abfd->format) < (int)bfd_unknown) \|\|
1d713d9e NC	128	((int)(abfd->format) >= (int)bfd_type_end))
	129	{
	130	bfd_set_error (bfd_error_invalid_operation);
	131	return false;
	132	}
252b5132 RH	133
	134	if (abfd->format != bfd_unknown)
	135	return (abfd->format == format)? true: false;
	136
252b5132 RH	137	/* Since the target type was defaulted, check them
252b5132 RH	138	all in the hope that one will be uniquely recognized. */
252b5132 RH	139	save_targ = abfd->xvec;
252b5132 RH	140	match_count = 0;
1d713d9e	141
252b5132 RH	142	if (matching)
	143	{
	144	matching_vector =
	145	(char *) bfd_malloc (sizeof (char ) *
	146	(_bfd_target_vector_entries + 1));
	147	if (!matching_vector)
	148	return false;
	149	matching_vector[0] = NULL;
	150	*matching = matching_vector;
	151	}
1d713d9e	152
252b5132 RH	153	right_targ = 0;
252b5132 RH	154
1d713d9e	155	/* Presume the answer is yes. */
252b5132 RH	156	abfd->format = format;
	157
	158	/* If the target type was explicitly specified, just check that target. */
1d713d9e NC	159	if (!abfd->target_defaulted)
	160	{
	161	if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0) /* rewind! */
252b5132	162	return false;
1d713d9e NC	163
	164	right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
	165
	166	if (right_targ)
252b5132	167	{
1d713d9e NC	168	abfd->xvec = right_targ; /* Set the target as returned. */
	169
	170	if (matching)
	171	free (matching_vector);
	172
	173	return true; /* File position has moved, BTW. */
252b5132	174	}
1d713d9e NC	175
	176	/* For a long time the code has dropped through to check all
	177	targets if the specified target was wrong. I don't know why,
	178	and I'm reluctant to change it. However, in the case of an
	179	archive, it can cause problems. If the specified target does
	180	not permit archives (e.g., the binary target), then we should
	181	not allow some other target to recognize it as an archive, but
	182	should instead allow the specified target to recognize it as an
	183	object. When I first made this change, it broke the PE target,
	184	because the specified pei-i386 target did not recognize the
	185	actual pe-i386 archive. Since there may be other problems of
	186	this sort, I changed this test to check only for the binary
	187	target. */
	188	if (format == bfd_archive && save_targ == &binary_vec)
252b5132	189	{
1d713d9e NC	190	abfd->xvec = save_targ;
	191	abfd->format = bfd_unknown;
	192
	193	if (matching)
	194	free (matching_vector);
	195
	196	bfd_set_error (bfd_error_file_not_recognized);
	197
	198	return false;
	199	}
	200	}
	201
	202	for (target = bfd_target_vector; *target != NULL; target++)
	203	{
	204	const bfd_target *temp;
	205
	206	if (*target == &binary_vec)
	207	continue;
	208
	209	abfd->xvec = target; / Change BFD's target temporarily */
	210
	211	if (bfd_seek (abfd, (file_ptr)0, SEEK_SET) != 0)
	212	return false;
	213
	214	/* If _bfd_check_format neglects to set bfd_error, assume
	215	bfd_error_wrong_format. We didn't used to even pay any
	216	attention to bfd_error, so I suspect that some
	217	_bfd_check_format might have this problem. */
	218	bfd_set_error (bfd_error_wrong_format);
	219
	220	temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
	221
	222	if (temp)
	223	{ /* This format checks out as ok! */
	224	right_targ = temp;
	225
252b5132 RH	226	if (matching)
252b5132 RH	227	{
1d713d9e NC	228	matching_vector[match_count] = temp->name;
	229	matching_vector[match_count + 1] = NULL;
	230	}
	231
	232	match_count++;
	233
	234	/* If this is the default target, accept it, even if other
	235	targets might match. People who want those other targets
	236	have to set the GNUTARGET variable. */
	237	if (temp == bfd_default_vector[0])
	238	{
	239	if (matching)
	240	{
	241	matching_vector[0] = temp->name;
	242	matching_vector[1] = NULL;
	243	}
	244	match_count = 1;
	245	break;
252b5132	246	}
252b5132	247	#ifdef GNU960
1d713d9e NC	248	/* Big- and little-endian b.out archives look the same, but it
	249	doesn't matter: there is no difference in their headers, and
	250	member file byte orders will (I hope) be handled appropriately
	251	by bfd. Ditto for big and little coff archives. And the 4
	252	coff/b.out object formats are unambiguous. So accept the
	253	first match we find. */
	254	break;
252b5132	255	#endif
1d713d9e NC	256	}
	257	else if (bfd_get_error () != bfd_error_wrong_format)
	258	{
	259	abfd->xvec = save_targ;
	260	abfd->format = bfd_unknown;
	261
	262	if (matching && bfd_get_error ()
	263	!= bfd_error_file_ambiguously_recognized)
	264	free (matching_vector);
	265
	266	return false;
	267	}
	268	}
	269
	270	if (match_count == 1)
	271	{
	272	abfd->xvec = right_targ; /* Change BFD's target permanently. */
	273
	274	if (matching)
252b5132	275	free (matching_vector);
1d713d9e NC	276
1d713d9e NC	277	return true; /* File position has moved, BTW. */
252b5132	278	}
252b5132	279
1d713d9e NC	280	abfd->xvec = save_targ; /* Restore original target type. */
	281	abfd->format = bfd_unknown; /* Restore original format. */
	282
252b5132 RH	283	if (match_count == 0)
	284	{
	285	bfd_set_error (bfd_error_file_not_recognized);
1d713d9e	286
252b5132 RH	287	if (matching)
	288	free (matching_vector);
	289	}
	290	else
	291	bfd_set_error (bfd_error_file_ambiguously_recognized);
1d713d9e	292
252b5132 RH	293	return false;
	294	}
	295
	296	/*
	297	FUNCTION
	298	bfd_set_format
	299
	300	SYNOPSIS
	301	boolean bfd_set_format(bfd *abfd, bfd_format format);
	302
	303	DESCRIPTION
	304	This function sets the file format of the BFD @var{abfd} to the
	305	format @var{format}. If the target set in the BFD does not
	306	support the format requested, the format is invalid, or the BFD
	307	is not open for writing, then an error occurs.
252b5132 RH	308	*/
	309
	310	boolean
	311	bfd_set_format (abfd, format)
	312	bfd *abfd;
	313	bfd_format format;
	314	{
252b5132 RH	315	if (bfd_read_p (abfd) \|\|
252b5132 RH	316	((int)abfd->format < (int)bfd_unknown) \|\|
1d713d9e NC	317	((int)abfd->format >= (int)bfd_type_end))
	318	{
	319	bfd_set_error (bfd_error_invalid_operation);
	320	return false;
	321	}
252b5132 RH	322
252b5132 RH	323	if (abfd->format != bfd_unknown)
1d713d9e	324	return (abfd->format == format) ? true : false;
252b5132	325
1d713d9e	326	/* Presume the answer is yes. */
252b5132 RH	327	abfd->format = format;
252b5132 RH	328
1d713d9e NC	329	if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd)))
	330	{
	331	abfd->format = bfd_unknown;
	332	return false;
	333	}
252b5132 RH	334
	335	return true;
	336	}
	337
	338
	339	/*
	340	FUNCTION
	341	bfd_format_string
	342
	343	SYNOPSIS
	344	CONST char *bfd_format_string(bfd_format format);
	345
	346	DESCRIPTION
	347	Return a pointer to a const string
	348	<<invalid>>, <<object>>, <<archive>>, <<core>>, or <<unknown>>,
	349	depending upon the value of @var{format}.
	350	*/
	351
	352	CONST char *
	353	bfd_format_string (format)
	354	bfd_format format;
	355	{
	356	if (((int)format <(int) bfd_unknown)
	357	\|\| ((int)format >=(int) bfd_type_end))
	358	return "invalid";
	359
1d713d9e NC	360	switch (format)
	361	{
	362	case bfd_object:
	363	return "object"; /* Linker/assember/compiler output. */
	364	case bfd_archive:
	365	return "archive"; /* Object archive file. */
	366	case bfd_core:
	367	return "core"; /* Core dump. */
	368	default:
	369	return "unknown";
	370	}
252b5132	371	}