[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, 2005, 2006, 2007
   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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */

#include "sysdep.h"
#include <limits.h>
#include "bfd.h"
#include "libbfd.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
}

FILE *
real_fopen (const char *filename, const char *modes)
{
#if defined (HAVE_FOPEN64)
  return fopen64 (filename, modes);
#else
  return fopen (filename, modes);
#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 this is an archive element, don't read past the end of
     this element.  */
  if (abfd->arelt_data != NULL)
    {
      size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size;
      if (size > maxbytes)
	size = maxbytes;
    }

  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 (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
	file_ptr 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?".
*/

file_ptr
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
7c192733 AC	3	Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3db64b00	4	1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
9553c638	5	Free Software Foundation, Inc.
7c192733	6
93509525 KD	7	Written by Cygnus Support.
	8
	9	This file is part of BFD, the Binary File Descriptor library.
	10
	11	This program is free software; you can redistribute it and/or modify
	12	it under the terms of the GNU General Public License as published by
	13	the Free Software Foundation; either version 2 of the License, or
	14	(at your option) any later version.
	15
	16	This program is distributed in the hope that it will be useful,
	17	but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	GNU General Public License for more details.
	20
	21	You should have received a copy of the GNU General Public License
	22	along with this program; if not, write to the Free Software
3e110533	23	Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
93509525 KD	24
93509525 KD	25	#include "sysdep.h"
3db64b00	26	#include <limits.h>
93509525 KD	27	#include "bfd.h"
	28	#include "libbfd.h"
	29
93509525 KD	30	#ifndef S_IXUSR
	31	#define S_IXUSR 0100 /* Execute by owner. */
	32	#endif
	33	#ifndef S_IXGRP
	34	#define S_IXGRP 0010 /* Execute by group. */
	35	#endif
	36	#ifndef S_IXOTH
	37	#define S_IXOTH 0001 /* Execute by others. */
	38	#endif
	39
7c192733 AC	40	file_ptr
	41	real_ftell (FILE *file)
	42	{
	43	#if defined (HAVE_FTELLO64)
	44	return ftello64 (file);
	45	#elif defined (HAVE_FTELLO)
	46	return ftello (file);
	47	#else
	48	return ftell (file);
	49	#endif
	50	}
	51
	52	int
	53	real_fseek (FILE *file, file_ptr offset, int whence)
	54	{
	55	#if defined (HAVE_FSEEKO64)
	56	return fseeko64 (file, offset, whence);
	57	#elif defined (HAVE_FSEEKO)
	58	return fseeko (file, offset, whence);
	59	#else
	60	return fseek (file, offset, whence);
	61	#endif
	62	}
	63
2e6f4fae DJ	64	FILE *
	65	real_fopen (const char filename, const char modes)
	66	{
	67	#if defined (HAVE_FOPEN64)
	68	return fopen64 (filename, modes);
	69	#else
	70	return fopen (filename, modes);
	71	#endif
	72	}
	73
40838a72 AC	74	/*
	75	INTERNAL_DEFINITION
	76	struct bfd_iovec
93509525	77
40838a72	78	DESCRIPTION
93509525	79
40838a72 AC	80	The <<struct bfd_iovec>> contains the internal file I/O class.
	81	Each <<BFD>> has an instance of this class and all file I/O is
	82	routed through it (it is assumed that the instance implements
	83	all methods listed below).
	84
	85	.struct bfd_iovec
	86	.{
	87	. {* To avoid problems with macros, a "b" rather than "f"
	88	. prefix is prepended to each method name. *}
	89	. {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
	90	. bytes starting at PTR. Return the number of bytes actually
	91	. transfered (a read past end-of-file returns less than NBYTES),
	92	. or -1 (setting <<bfd_error>>) if an error occurs. *}
	93	. file_ptr (bread) (struct bfd abfd, void *ptr, file_ptr nbytes);
	94	. file_ptr (bwrite) (struct bfd abfd, const void *ptr,
	95	. file_ptr nbytes);
	96	. {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
	97	. if an error occurs. *}
	98	. file_ptr (btell) (struct bfd abfd);
	99	. {* For the following, on successful completion a value of 0 is returned.
	100	. Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *}
	101	. int (bseek) (struct bfd abfd, file_ptr offset, int whence);
	102	. int (bclose) (struct bfd abfd);
	103	. int (bflush) (struct bfd abfd);
	104	. int (bstat) (struct bfd abfd, struct stat *sb);
	105	.};
93509525	106
40838a72	107	*/
93509525	108
93509525 KD	109
	110	/* Return value is amount read. */
	111
	112	bfd_size_type
c58b9523	113	bfd_bread (void ptr, bfd_size_type size, bfd abfd)
93509525 KD	114	{
	115	size_t nread;
	116
1fb41da4 AM	117	/* If this is an archive element, don't read past the end of
	118	this element. */
	119	if (abfd->arelt_data != NULL)
	120	{
	121	size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size;
	122	if (size > maxbytes)
	123	size = maxbytes;
	124	}
	125
93509525 KD	126	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	127	{
	128	struct bfd_in_memory *bim;
	129	bfd_size_type get;
	130
c58b9523	131	bim = abfd->iostream;
93509525 KD	132	get = size;
	133	if (abfd->where + get > bim->size)
	134	{
	135	if (bim->size < (bfd_size_type) abfd->where)
	136	get = 0;
	137	else
	138	get = bim->size - abfd->where;
	139	bfd_set_error (bfd_error_file_truncated);
	140	}
	141	memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
	142	abfd->where += get;
	143	return get;
	144	}
	145
69fd4758 NC	146	if (abfd->iovec)
	147	nread = abfd->iovec->bread (abfd, ptr, size);
	148	else
	149	nread = 0;
93509525 KD	150	if (nread != (size_t) -1)
	151	abfd->where += nread;
	152
93509525 KD	153	return nread;
	154	}
	155
	156	bfd_size_type
c58b9523	157	bfd_bwrite (const void ptr, bfd_size_type size, bfd abfd)
93509525 KD	158	{
	159	size_t nwrote;
	160
	161	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	162	{
c58b9523	163	struct bfd_in_memory *bim = abfd->iostream;
69fd4758	164
93509525 KD	165	size = (size_t) size;
	166	if (abfd->where + size > bim->size)
	167	{
	168	bfd_size_type newsize, oldsize;
	169
	170	oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
	171	bim->size = abfd->where + size;
	172	/* Round up to cut down on memory fragmentation */
	173	newsize = (bim->size + 127) & ~(bfd_size_type) 127;
	174	if (newsize > oldsize)
	175	{
c58b9523	176	bim->buffer = bfd_realloc (bim->buffer, newsize);
93509525 KD	177	if (bim->buffer == 0)
	178	{
	179	bim->size = 0;
	180	return 0;
	181	}
	182	}
	183	}
	184	memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
	185	abfd->where += size;
	186	return size;
	187	}
	188
69fd4758 NC	189	if (abfd->iovec)
	190	nwrote = abfd->iovec->bwrite (abfd, ptr, size);
	191	else
	192	nwrote = 0;
	193
93509525 KD	194	if (nwrote != (size_t) -1)
	195	abfd->where += nwrote;
	196	if (nwrote != size)
	197	{
	198	#ifdef ENOSPC
	199	errno = ENOSPC;
	200	#endif
	201	bfd_set_error (bfd_error_system_call);
	202	}
	203	return nwrote;
	204	}
	205
7c192733	206	file_ptr
c58b9523	207	bfd_tell (bfd *abfd)
93509525 KD	208	{
	209	file_ptr ptr;
	210
	211	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	212	return abfd->where;
	213
69fd4758 NC	214	if (abfd->iovec)
	215	{
	216	ptr = abfd->iovec->btell (abfd);
	217
	218	if (abfd->my_archive)
	219	ptr -= abfd->origin;
	220	}
	221	else
	222	ptr = 0;
93509525	223
93509525 KD	224	abfd->where = ptr;
	225	return ptr;
	226	}
	227
	228	int
c58b9523	229	bfd_flush (bfd *abfd)
93509525 KD	230	{
	231	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	232	return 0;
69fd4758 NC	233
	234	if (abfd->iovec)
	235	return abfd->iovec->bflush (abfd);
	236	return 0;
93509525 KD	237	}
	238
	239	/* Returns 0 for success, negative value for failure (in which case
	240	bfd_get_error can retrieve the error code). */
	241	int
c58b9523	242	bfd_stat (bfd abfd, struct stat statbuf)
93509525	243	{
93509525 KD	244	int result;
	245
	246	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	247	abort ();
	248
69fd4758 NC	249	if (abfd->iovec)
	250	result = abfd->iovec->bstat (abfd, statbuf);
	251	else
	252	result = -1;
	253
93509525 KD	254	if (result < 0)
	255	bfd_set_error (bfd_error_system_call);
	256	return result;
	257	}
	258
	259	/* Returns 0 for success, nonzero for failure (in which case bfd_get_error
	260	can retrieve the error code). */
	261
	262	int
c58b9523	263	bfd_seek (bfd *abfd, file_ptr position, int direction)
93509525 KD	264	{
93509525 KD	265	int result;
7c192733	266	file_ptr file_position;
93509525 KD	267	/* For the time being, a BFD may not seek to it's end. The problem
	268	is that we don't easily have a way to recognize the end of an
	269	element in an archive. */
	270
	271	BFD_ASSERT (direction == SEEK_SET \|\| direction == SEEK_CUR);
	272
	273	if (direction == SEEK_CUR && position == 0)
	274	return 0;
	275
	276	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	277	{
	278	struct bfd_in_memory *bim;
	279
c58b9523	280	bim = abfd->iostream;
93509525 KD	281
	282	if (direction == SEEK_SET)
	283	abfd->where = position;
	284	else
	285	abfd->where += position;
	286
	287	if (abfd->where > bim->size)
	288	{
	289	if ((abfd->direction == write_direction) \|\|
	290	(abfd->direction == both_direction))
	291	{
	292	bfd_size_type newsize, oldsize;
69fd4758	293
93509525 KD	294	oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
	295	bim->size = abfd->where;
	296	/* Round up to cut down on memory fragmentation */
	297	newsize = (bim->size + 127) & ~(bfd_size_type) 127;
	298	if (newsize > oldsize)
	299	{
c58b9523	300	bim->buffer = bfd_realloc (bim->buffer, newsize);
93509525 KD	301	if (bim->buffer == 0)
	302	{
	303	bim->size = 0;
	304	return -1;
	305	}
	306	}
	307	}
	308	else
	309	{
	310	abfd->where = bim->size;
	311	bfd_set_error (bfd_error_file_truncated);
	312	return -1;
	313	}
	314	}
	315	return 0;
	316	}
	317
	318	if (abfd->format != bfd_archive && abfd->my_archive == 0)
	319	{
93509525 KD	320	if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
	321	return 0;
	322	}
	323	else
	324	{
	325	/* We need something smarter to optimize access to archives.
	326	Currently, anything inside an archive is read via the file
	327	handle for the archive. Which means that a bfd_seek on one
	328	component affects the `current position' in the archive, as
	329	well as in any other component.
	330
	331	It might be sufficient to put a spike through the cache
	332	abstraction, and look to the archive for the file position,
	333	but I think we should try for something cleaner.
	334
	335	In the meantime, no optimization for archives. */
	336	}
	337
93509525 KD	338	file_position = position;
	339	if (direction == SEEK_SET && abfd->my_archive != NULL)
	340	file_position += abfd->origin;
	341
69fd4758 NC	342	if (abfd->iovec)
	343	result = abfd->iovec->bseek (abfd, file_position, direction);
	344	else
	345	result = -1;
	346
93509525 KD	347	if (result != 0)
	348	{
	349	int hold_errno = errno;
	350
	351	/* Force redetermination of `where' field. */
	352	bfd_tell (abfd);
	353
	354	/* An EINVAL error probably means that the file offset was
	355	absurd. */
	356	if (hold_errno == EINVAL)
	357	bfd_set_error (bfd_error_file_truncated);
	358	else
	359	{
	360	bfd_set_error (bfd_error_system_call);
	361	errno = hold_errno;
	362	}
	363	}
	364	else
	365	{
	366	/* Adjust `where' field. */
	367	if (direction == SEEK_SET)
	368	abfd->where = position;
	369	else
	370	abfd->where += position;
	371	}
	372	return result;
	373	}
	374
	375	/*
	376	FUNCTION
	377	bfd_get_mtime
	378
	379	SYNOPSIS
c58b9523	380	long bfd_get_mtime (bfd *abfd);
93509525 KD	381
	382	DESCRIPTION
	383	Return the file modification time (as read from the file system, or
	384	from the archive header for archive members).
	385
	386	*/
	387
	388	long
c58b9523	389	bfd_get_mtime (bfd *abfd)
93509525	390	{
93509525 KD	391	struct stat buf;
	392
	393	if (abfd->mtime_set)
	394	return abfd->mtime;
	395
69fd4758 NC	396	if (abfd->iovec == NULL)
	397	return 0;
	398
40838a72	399	if (abfd->iovec->bstat (abfd, &buf) != 0)
93509525 KD	400	return 0;
	401
	402	abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
	403	return buf.st_mtime;
	404	}
	405
	406	/*
	407	FUNCTION
	408	bfd_get_size
	409
	410	SYNOPSIS
74633dd0	411	file_ptr bfd_get_size (bfd *abfd);
93509525 KD	412
	413	DESCRIPTION
	414	Return the file size (as read from file system) for the file
	415	associated with BFD @var{abfd}.
	416
	417	The initial motivation for, and use of, this routine is not
	418	so we can get the exact size of the object the BFD applies to, since
	419	that might not be generally possible (archive members for example).
	420	It would be ideal if someone could eventually modify
	421	it so that such results were guaranteed.
	422
	423	Instead, we want to ask questions like "is this NNN byte sized
	424	object I'm about to try read from file offset YYY reasonable?"
	425	As as example of where we might do this, some object formats
	426	use string tables for which the first <<sizeof (long)>> bytes of the
	427	table contain the size of the table itself, including the size bytes.
	428	If an application tries to read what it thinks is one of these
	429	string tables, without some way to validate the size, and for
	430	some reason the size is wrong (byte swapping error, wrong location
	431	for the string table, etc.), the only clue is likely to be a read
	432	error when it tries to read the table, or a "virtual memory
	433	exhausted" error when it tries to allocate 15 bazillon bytes
	434	of space for the 15 bazillon byte table it is about to read.
5c4491d3	435	This function at least allows us to answer the question, "is the
93509525 KD	436	size reasonable?".
	437	*/
	438
74633dd0	439	file_ptr
c58b9523	440	bfd_get_size (bfd *abfd)
93509525	441	{
93509525 KD	442	struct stat buf;
	443
	444	if ((abfd->flags & BFD_IN_MEMORY) != 0)
	445	return ((struct bfd_in_memory *) abfd->iostream)->size;
	446
69fd4758 NC	447	if (abfd->iovec == NULL)
	448	return 0;
	449
40838a72	450	if (abfd->iovec->bstat (abfd, &buf) != 0)
93509525 KD	451	return 0;
	452
	453	return buf.st_size;
	454	}