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/* 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, 2008

   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 3 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_or_free (bim->buffer, newsize);

              if (bim->buffer == NULL)

                {

                  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_or_free (bim->buffer, newsize);

                  if (bim->buffer == NULL)

                    {

                      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;

}