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

/* Low-level I/O routines for BFDs.

   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   1999, 2000, 2001, 2002, 2003, 2004 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.  */

#include "sysdep.h"

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

#include <limits.h>

#ifndef S_IXUSR
#define S_IXUSR 0100    /* Execute by owner.  */
#endif
#ifndef S_IXGRP
#define S_IXGRP 0010    /* Execute by group.  */
#endif
#ifndef S_IXOTH
#define S_IXOTH 0001    /* Execute by others.  */
#endif

file_ptr
real_ftell (FILE *file)
{
#if defined (HAVE_FTELLO64)
  return ftello64 (file);
#elif defined (HAVE_FTELLO)
  return ftello (file);
#else
  return ftell (file);
#endif
}

int
real_fseek (FILE *file, file_ptr offset, int whence)
{
#if defined (HAVE_FSEEKO64)
  return fseeko64 (file, offset, whence);
#elif defined (HAVE_FSEEKO)
  return fseeko (file, offset, whence);
#else
  return fseek (file, offset, whence);
#endif
}

/*
INTERNAL_DEFINITION
	struct bfd_iovec

DESCRIPTION

	The <<struct bfd_iovec>> contains the internal file I/O class.
	Each <<BFD>> has an instance of this class and all file I/O is
	routed through it (it is assumed that the instance implements
	all methods listed below).

.struct bfd_iovec
.{
.  {* To avoid problems with macros, a "b" rather than "f"
.     prefix is prepended to each method name.  *}
.  {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
.     bytes starting at PTR.  Return the number of bytes actually
.     transfered (a read past end-of-file returns less than NBYTES),
.     or -1 (setting <<bfd_error>>) if an error occurs.  *}
.  file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
.  file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
.                      file_ptr nbytes);
.  {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
.     if an error occurs.  *}
.  file_ptr (*btell) (struct bfd *abfd);
.  {* For the following, on successful completion a value of 0 is returned.
.     Otherwise, a value of -1 is returned (and  <<bfd_error>> is set).  *}
.  int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
.  int (*bclose) (struct bfd *abfd);
.  int (*bflush) (struct bfd *abfd);
.  int (*bstat) (struct bfd *abfd, struct stat *sb);
.};

*/


/* Return value is amount read.  */

bfd_size_type
bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
{
  size_t nread;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    {
      struct bfd_in_memory *bim;
      bfd_size_type get;

      bim = abfd->iostream;
      get = size;
      if (abfd->where + get > bim->size)
	{
	  if (bim->size < (bfd_size_type) abfd->where)
	    get = 0;
	  else
	    get = bim->size - abfd->where;
	  bfd_set_error (bfd_error_file_truncated);
	}
      memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
      abfd->where += get;
      return get;
    }

  if (abfd->iovec)
    nread = abfd->iovec->bread (abfd, ptr, size);
  else
    nread = 0;
  if (nread != (size_t) -1)
    abfd->where += nread;

  return nread;
}

bfd_size_type
bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
{
  size_t nwrote;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    {
      struct bfd_in_memory *bim = abfd->iostream;

      size = (size_t) size;
      if (abfd->where + size > bim->size)
	{
	  bfd_size_type newsize, oldsize;

	  oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
	  bim->size = abfd->where + size;
	  /* Round up to cut down on memory fragmentation */
	  newsize = (bim->size + 127) & ~(bfd_size_type) 127;
	  if (newsize > oldsize)
	    {
	      bim->buffer = bfd_realloc (bim->buffer, newsize);
	      if (bim->buffer == 0)
		{
		  bim->size = 0;
		  return 0;
		}
	    }
	}
      memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
      abfd->where += size;
      return size;
    }

  if (abfd->iovec)
    nwrote = abfd->iovec->bwrite (abfd, ptr, size);
  else
    nwrote = 0;

  if (nwrote != (size_t) -1)
    abfd->where += nwrote;
  if (nwrote != size)
    {
#ifdef ENOSPC
      errno = ENOSPC;
#endif
      bfd_set_error (bfd_error_system_call);
    }
  return nwrote;
}

file_ptr
bfd_tell (bfd *abfd)
{
  file_ptr ptr;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    return abfd->where;

  if (abfd->iovec)
    {
      ptr = abfd->iovec->btell (abfd);

      if (abfd->my_archive)
	ptr -= abfd->origin;
    }
  else
    ptr = 0;

  abfd->where = ptr;
  return ptr;
}

int
bfd_flush (bfd *abfd)
{
  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    return 0;

  if (abfd->iovec)
    return abfd->iovec->bflush (abfd);
  return 0;
}

/* Returns 0 for success, negative value for failure (in which case
   bfd_get_error can retrieve the error code).  */
int
bfd_stat (bfd *abfd, struct stat *statbuf)
{
  int result;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    abort ();

  if (abfd->iovec)
    result = abfd->iovec->bstat (abfd, statbuf);
  else
    result = -1;

  if (result < 0)
    bfd_set_error (bfd_error_system_call);
  return result;
}

/* Returns 0 for success, nonzero for failure (in which case bfd_get_error
   can retrieve the error code).  */

int
bfd_seek (bfd *abfd, file_ptr position, int direction)
{
  int result;
  file_ptr file_position;
  /* For the time being, a BFD may not seek to it's end.  The problem
     is that we don't easily have a way to recognize the end of an
     element in an archive.  */

  BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);

  if (direction == SEEK_CUR && position == 0)
    return 0;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    {
      struct bfd_in_memory *bim;

      bim = abfd->iostream;

      if (direction == SEEK_SET)
	abfd->where = position;
      else
	abfd->where += position;

      if (abfd->where > bim->size)
	{
	  if ((abfd->direction == write_direction) ||
	      (abfd->direction == both_direction))
	    {
	      bfd_size_type newsize, oldsize;

	      oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
	      bim->size = abfd->where;
	      /* Round up to cut down on memory fragmentation */
	      newsize = (bim->size + 127) & ~(bfd_size_type) 127;
	      if (newsize > oldsize)
	        {
		  bim->buffer = bfd_realloc (bim->buffer, newsize);
		  if (bim->buffer == 0)
		    {
		      bim->size = 0;
		      return -1;
		    }
	        }
	    }
	  else
	    {
	      abfd->where = bim->size;
	      bfd_set_error (bfd_error_file_truncated);
	      return -1;
	    }
	}
      return 0;
    }

  if (abfd->format != bfd_archive && abfd->my_archive == 0)
    {
#if 0
      /* Explanation for this code: I'm only about 95+% sure that the above
	 conditions are sufficient and that all i/o calls are properly
	 adjusting the `where' field.  So this is sort of an `assert'
	 that the `where' field is correct.  If we can go a while without
	 tripping the abort, we can probably safely disable this code,
	 so that the real optimizations happen.  */
      file_ptr where_am_i_now;
      where_am_i_now = real_ftell (bfd_cache_lookup (abfd));
      if (abfd->my_archive)
	where_am_i_now -= abfd->origin;
      if (where_am_i_now != abfd->where)
	abort ();
#endif
      if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
	return 0;
    }
  else
    {
      /* We need something smarter to optimize access to archives.
	 Currently, anything inside an archive is read via the file
	 handle for the archive.  Which means that a bfd_seek on one
	 component affects the `current position' in the archive, as
	 well as in any other component.

	 It might be sufficient to put a spike through the cache
	 abstraction, and look to the archive for the file position,
	 but I think we should try for something cleaner.

	 In the meantime, no optimization for archives.  */
    }

  file_position = position;
  if (direction == SEEK_SET && abfd->my_archive != NULL)
    file_position += abfd->origin;

  if (abfd->iovec)
    result = abfd->iovec->bseek (abfd, file_position, direction);
  else
    result = -1;

  if (result != 0)
    {
      int hold_errno = errno;

      /* Force redetermination of `where' field.  */
      bfd_tell (abfd);

      /* An EINVAL error probably means that the file offset was
         absurd.  */
      if (hold_errno == EINVAL)
	bfd_set_error (bfd_error_file_truncated);
      else
	{
	  bfd_set_error (bfd_error_system_call);
	  errno = hold_errno;
	}
    }
  else
    {
      /* Adjust `where' field.  */
      if (direction == SEEK_SET)
	abfd->where = position;
      else
	abfd->where += position;
    }
  return result;
}

/*
FUNCTION
	bfd_get_mtime

SYNOPSIS
	long bfd_get_mtime (bfd *abfd);

DESCRIPTION
	Return the file modification time (as read from the file system, or
	from the archive header for archive members).

*/

long
bfd_get_mtime (bfd *abfd)
{
  struct stat buf;

  if (abfd->mtime_set)
    return abfd->mtime;

  if (abfd->iovec == NULL)
    return 0;

  if (abfd->iovec->bstat (abfd, &buf) != 0)
    return 0;

  abfd->mtime = buf.st_mtime;		/* Save value in case anyone wants it */
  return buf.st_mtime;
}

/*
FUNCTION
	bfd_get_size

SYNOPSIS
	long bfd_get_size (bfd *abfd);

DESCRIPTION
	Return the file size (as read from file system) for the file
	associated with BFD @var{abfd}.

	The initial motivation for, and use of, this routine is not
	so we can get the exact size of the object the BFD applies to, since
	that might not be generally possible (archive members for example).
	It would be ideal if someone could eventually modify
	it so that such results were guaranteed.

	Instead, we want to ask questions like "is this NNN byte sized
	object I'm about to try read from file offset YYY reasonable?"
	As as example of where we might do this, some object formats
	use string tables for which the first <<sizeof (long)>> bytes of the
	table contain the size of the table itself, including the size bytes.
	If an application tries to read what it thinks is one of these
	string tables, without some way to validate the size, and for
	some reason the size is wrong (byte swapping error, wrong location
	for the string table, etc.), the only clue is likely to be a read
	error when it tries to read the table, or a "virtual memory
	exhausted" error when it tries to allocate 15 bazillon bytes
	of space for the 15 bazillon byte table it is about to read.
	This function at least allows us to answer the question, "is the
	size reasonable?".
*/

long
bfd_get_size (bfd *abfd)
{
  struct stat buf;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    return ((struct bfd_in_memory *) abfd->iostream)->size;

  if (abfd->iovec == NULL)
    return 0;

  if (abfd->iovec->bstat (abfd, &buf) != 0)
    return 0;

  return buf.st_size;
}
Commit	Line	Data
93509525	1	/* Low-level I/O routines for BFDs.
7c192733 AC	2
	3	Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
	4	1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
	5
93509525 KD	6	Written by Cygnus Support.
	7
	8	This file is part of BFD, the Binary File Descriptor library.
	9
	10	This program is free software; you can redistribute it and/or modify
	11	it under the terms of the GNU General Public License as published by
	12	the Free Software Foundation; either version 2 of the License, or
	13	(at your option) any later version.
	14
	15	This program is distributed in the hope that it will be useful,
	16	but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	GNU General Public License for more details.
	19
	20	You should have received a copy of the GNU General Public License
	21	along with this program; if not, write to the Free Software
	22	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
	23
	24	#include "sysdep.h"
	25
	26	#include "bfd.h"
	27	#include "libbfd.h"
	28
	29	#include <limits.h>
	30
	31	#ifndef S_IXUSR
	32	#define S_IXUSR 0100 /* Execute by owner. */
	33	#endif
	34	#ifndef S_IXGRP
	35	#define S_IXGRP 0010 /* Execute by group. */
	36	#endif
	37	#ifndef S_IXOTH
	38	#define S_IXOTH 0001 /* Execute by others. */
	39	#endif
	40
7c192733 AC	41	file_ptr
	42	real_ftell (FILE *file)
	43	{
	44	#if defined (HAVE_FTELLO64)
	45	return ftello64 (file);
	46	#elif defined (HAVE_FTELLO)
	47	return ftello (file);
	48	#else
	49	return ftell (file);
	50	#endif
	51	}
	52
	53	int
	54	real_fseek (FILE *file, file_ptr offset, int whence)
	55	{
	56	#if defined (HAVE_FSEEKO64)
	57	return fseeko64 (file, offset, whence);
	58	#elif defined (HAVE_FSEEKO)
	59	return fseeko (file, offset, whence);
	60	#else
	61	return fseek (file, offset, whence);
	62	#endif
	63	}
	64
40838a72 AC	65	/*
	66	INTERNAL_DEFINITION
	67	struct bfd_iovec
93509525	68
40838a72	69	DESCRIPTION
93509525	70
40838a72 AC	71	The <<struct bfd_iovec>> contains the internal file I/O class.
	72	Each <<BFD>> has an instance of this class and all file I/O is
	73	routed through it (it is assumed that the instance implements
	74	all methods listed below).
	75
	76	.struct bfd_iovec
	77	.{
	78	. {* To avoid problems with macros, a "b" rather than "f"
	79	. prefix is prepended to each method name. *}
	80	. {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
	81	. bytes starting at PTR. Return the number of bytes actually
	82	. transfered (a read past end-of-file returns less than NBYTES),
	83	. or -1 (setting <<bfd_error>>) if an error occurs. *}
	84	. file_ptr (bread) (struct bfd abfd, void *ptr, file_ptr nbytes);
	85	. file_ptr (bwrite) (struct bfd abfd, const void *ptr,
	86	. file_ptr nbytes);
	87	. {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
	88	. if an error occurs. *}
	89	. file_ptr (btell) (struct bfd abfd);
	90	. {* For the following, on successful completion a value of 0 is returned.
	91	. Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *}
	92	. int (bseek) (struct bfd abfd, file_ptr offset, int whence);
	93	. int (bclose) (struct bfd abfd);
	94	. int (bflush) (struct bfd abfd);
	95	. int (bstat) (struct bfd abfd, struct stat *sb);
	96	.};
93509525	97
40838a72	98	*/
93509525	99
93509525 KD	100
	101	/* Return value is amount read. */
	102
	103	bfd_size_type
c58b9523	104	bfd_bread (void ptr, bfd_size_type size, bfd abfd)
93509525 KD	105	{
	106	size_t nread;
	107
	108	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	109	{
	110	struct bfd_in_memory *bim;
	111	bfd_size_type get;
	112
c58b9523	113	bim = abfd->iostream;
93509525 KD	114	get = size;
	115	if (abfd->where + get > bim->size)
	116	{
	117	if (bim->size < (bfd_size_type) abfd->where)
	118	get = 0;
	119	else
	120	get = bim->size - abfd->where;
	121	bfd_set_error (bfd_error_file_truncated);
	122	}
	123	memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
	124	abfd->where += get;
	125	return get;
	126	}
	127
69fd4758 NC	128	if (abfd->iovec)
	129	nread = abfd->iovec->bread (abfd, ptr, size);
	130	else
	131	nread = 0;
93509525 KD	132	if (nread != (size_t) -1)
	133	abfd->where += nread;
	134
93509525 KD	135	return nread;
	136	}
	137
	138	bfd_size_type
c58b9523	139	bfd_bwrite (const void ptr, bfd_size_type size, bfd abfd)
93509525 KD	140	{
	141	size_t nwrote;
	142
	143	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	144	{
c58b9523	145	struct bfd_in_memory *bim = abfd->iostream;
69fd4758	146
93509525 KD	147	size = (size_t) size;
	148	if (abfd->where + size > bim->size)
	149	{
	150	bfd_size_type newsize, oldsize;
	151
	152	oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
	153	bim->size = abfd->where + size;
	154	/* Round up to cut down on memory fragmentation */
	155	newsize = (bim->size + 127) & ~(bfd_size_type) 127;
	156	if (newsize > oldsize)
	157	{
c58b9523	158	bim->buffer = bfd_realloc (bim->buffer, newsize);
93509525 KD	159	if (bim->buffer == 0)
	160	{
	161	bim->size = 0;
	162	return 0;
	163	}
	164	}
	165	}
	166	memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
	167	abfd->where += size;
	168	return size;
	169	}
	170
69fd4758 NC	171	if (abfd->iovec)
	172	nwrote = abfd->iovec->bwrite (abfd, ptr, size);
	173	else
	174	nwrote = 0;
	175
93509525 KD	176	if (nwrote != (size_t) -1)
	177	abfd->where += nwrote;
	178	if (nwrote != size)
	179	{
	180	#ifdef ENOSPC
	181	errno = ENOSPC;
	182	#endif
	183	bfd_set_error (bfd_error_system_call);
	184	}
	185	return nwrote;
	186	}
	187
7c192733	188	file_ptr
c58b9523	189	bfd_tell (bfd *abfd)
93509525 KD	190	{
	191	file_ptr ptr;
	192
	193	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	194	return abfd->where;
	195
69fd4758 NC	196	if (abfd->iovec)
	197	{
	198	ptr = abfd->iovec->btell (abfd);
	199
	200	if (abfd->my_archive)
	201	ptr -= abfd->origin;
	202	}
	203	else
	204	ptr = 0;
93509525	205
93509525 KD	206	abfd->where = ptr;
	207	return ptr;
	208	}
	209
	210	int
c58b9523	211	bfd_flush (bfd *abfd)
93509525 KD	212	{
	213	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	214	return 0;
69fd4758 NC	215
	216	if (abfd->iovec)
	217	return abfd->iovec->bflush (abfd);
	218	return 0;
93509525 KD	219	}
	220
	221	/* Returns 0 for success, negative value for failure (in which case
	222	bfd_get_error can retrieve the error code). */
	223	int
c58b9523	224	bfd_stat (bfd abfd, struct stat statbuf)
93509525	225	{
93509525 KD	226	int result;
	227
	228	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	229	abort ();
	230
69fd4758 NC	231	if (abfd->iovec)
	232	result = abfd->iovec->bstat (abfd, statbuf);
	233	else
	234	result = -1;
	235
93509525 KD	236	if (result < 0)
	237	bfd_set_error (bfd_error_system_call);
	238	return result;
	239	}
	240
	241	/* Returns 0 for success, nonzero for failure (in which case bfd_get_error
	242	can retrieve the error code). */
	243
	244	int
c58b9523	245	bfd_seek (bfd *abfd, file_ptr position, int direction)
93509525 KD	246	{
93509525 KD	247	int result;
7c192733	248	file_ptr file_position;
93509525 KD	249	/* For the time being, a BFD may not seek to it's end. The problem
	250	is that we don't easily have a way to recognize the end of an
	251	element in an archive. */
	252
	253	BFD_ASSERT (direction == SEEK_SET \|\| direction == SEEK_CUR);
	254
	255	if (direction == SEEK_CUR && position == 0)
	256	return 0;
	257
	258	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	259	{
	260	struct bfd_in_memory *bim;
	261
c58b9523	262	bim = abfd->iostream;
93509525 KD	263
	264	if (direction == SEEK_SET)
	265	abfd->where = position;
	266	else
	267	abfd->where += position;
	268
	269	if (abfd->where > bim->size)
	270	{
	271	if ((abfd->direction == write_direction) \|\|
	272	(abfd->direction == both_direction))
	273	{
	274	bfd_size_type newsize, oldsize;
69fd4758	275
93509525 KD	276	oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
	277	bim->size = abfd->where;
	278	/* Round up to cut down on memory fragmentation */
	279	newsize = (bim->size + 127) & ~(bfd_size_type) 127;
	280	if (newsize > oldsize)
	281	{
c58b9523	282	bim->buffer = bfd_realloc (bim->buffer, newsize);
93509525 KD	283	if (bim->buffer == 0)
	284	{
	285	bim->size = 0;
	286	return -1;
	287	}
	288	}
	289	}
	290	else
	291	{
	292	abfd->where = bim->size;
	293	bfd_set_error (bfd_error_file_truncated);
	294	return -1;
	295	}
	296	}
	297	return 0;
	298	}
	299
	300	if (abfd->format != bfd_archive && abfd->my_archive == 0)
	301	{
	302	#if 0
	303	/* Explanation for this code: I'm only about 95+% sure that the above
	304	conditions are sufficient and that all i/o calls are properly
	305	adjusting the `where' field. So this is sort of an `assert'
	306	that the `where' field is correct. If we can go a while without
	307	tripping the abort, we can probably safely disable this code,
	308	so that the real optimizations happen. */
	309	file_ptr where_am_i_now;
7c192733	310	where_am_i_now = real_ftell (bfd_cache_lookup (abfd));
93509525 KD	311	if (abfd->my_archive)
	312	where_am_i_now -= abfd->origin;
	313	if (where_am_i_now != abfd->where)
	314	abort ();
	315	#endif
	316	if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
	317	return 0;
	318	}
	319	else
	320	{
	321	/* We need something smarter to optimize access to archives.
	322	Currently, anything inside an archive is read via the file
	323	handle for the archive. Which means that a bfd_seek on one
	324	component affects the `current position' in the archive, as
	325	well as in any other component.
	326
	327	It might be sufficient to put a spike through the cache
	328	abstraction, and look to the archive for the file position,
	329	but I think we should try for something cleaner.
	330
	331	In the meantime, no optimization for archives. */
	332	}
	333
93509525 KD	334	file_position = position;
	335	if (direction == SEEK_SET && abfd->my_archive != NULL)
	336	file_position += abfd->origin;
	337
69fd4758 NC	338	if (abfd->iovec)
	339	result = abfd->iovec->bseek (abfd, file_position, direction);
	340	else
	341	result = -1;
	342
93509525 KD	343	if (result != 0)
	344	{
	345	int hold_errno = errno;
	346
	347	/* Force redetermination of `where' field. */
	348	bfd_tell (abfd);
	349
	350	/* An EINVAL error probably means that the file offset was
	351	absurd. */
	352	if (hold_errno == EINVAL)
	353	bfd_set_error (bfd_error_file_truncated);
	354	else
	355	{
	356	bfd_set_error (bfd_error_system_call);
	357	errno = hold_errno;
	358	}
	359	}
	360	else
	361	{
	362	/* Adjust `where' field. */
	363	if (direction == SEEK_SET)
	364	abfd->where = position;
	365	else
	366	abfd->where += position;
	367	}
	368	return result;
	369	}
	370
	371	/*
	372	FUNCTION
	373	bfd_get_mtime
	374
	375	SYNOPSIS
c58b9523	376	long bfd_get_mtime (bfd *abfd);
93509525 KD	377
	378	DESCRIPTION
	379	Return the file modification time (as read from the file system, or
	380	from the archive header for archive members).
	381
	382	*/
	383
	384	long
c58b9523	385	bfd_get_mtime (bfd *abfd)
93509525	386	{
93509525 KD	387	struct stat buf;
	388
	389	if (abfd->mtime_set)
	390	return abfd->mtime;
	391
69fd4758 NC	392	if (abfd->iovec == NULL)
	393	return 0;
	394
40838a72	395	if (abfd->iovec->bstat (abfd, &buf) != 0)
93509525 KD	396	return 0;
	397
	398	abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
	399	return buf.st_mtime;
	400	}
	401
	402	/*
	403	FUNCTION
	404	bfd_get_size
	405
	406	SYNOPSIS
c58b9523	407	long bfd_get_size (bfd *abfd);
93509525 KD	408
	409	DESCRIPTION
	410	Return the file size (as read from file system) for the file
	411	associated with BFD @var{abfd}.
	412
	413	The initial motivation for, and use of, this routine is not
	414	so we can get the exact size of the object the BFD applies to, since
	415	that might not be generally possible (archive members for example).
	416	It would be ideal if someone could eventually modify
	417	it so that such results were guaranteed.
	418
	419	Instead, we want to ask questions like "is this NNN byte sized
	420	object I'm about to try read from file offset YYY reasonable?"
	421	As as example of where we might do this, some object formats
	422	use string tables for which the first <<sizeof (long)>> bytes of the
	423	table contain the size of the table itself, including the size bytes.
	424	If an application tries to read what it thinks is one of these
	425	string tables, without some way to validate the size, and for
	426	some reason the size is wrong (byte swapping error, wrong location
	427	for the string table, etc.), the only clue is likely to be a read
	428	error when it tries to read the table, or a "virtual memory
	429	exhausted" error when it tries to allocate 15 bazillon bytes
	430	of space for the 15 bazillon byte table it is about to read.
5c4491d3	431	This function at least allows us to answer the question, "is the
93509525 KD	432	size reasonable?".
	433	*/
	434
	435	long
c58b9523	436	bfd_get_size (bfd *abfd)
93509525	437	{
93509525 KD	438	struct stat buf;
	439
	440	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	441	return ((struct bfd_in_memory *) abfd->iostream)->size;
	442
69fd4758 NC	443	if (abfd->iovec == NULL)
	444	return 0;
	445
40838a72	446	if (abfd->iovec->bstat (abfd, &buf) != 0)
93509525 KD	447	return 0;
	448
	449	return buf.st_size;
	450	}