bfdio.c   [plain text]

/* Assorted BFD support routines, only used internally.
   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001
   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

/* Note that archive entries don't have streams; they share their parent's.
   This allows someone to play with the iostream behind BFD's back.

   Also, note that the origin pointer points to the beginning of a file's
   contents (0 for non-archive elements).  For archive entries this is the
   first octet in the file, NOT the beginning of the archive header. */

/* Return value is amount read (FIXME: how are errors and end of file dealt
   with?  We never call bfd_set_error, which is probably a mistake).  */

bfd_size_type
bfd_bread (ptr, size, abfd)
     PTR ptr;
     bfd_size_type size;
     bfd *abfd;
{
  while (abfd->my_archive != NULL)
    abfd = abfd->my_archive;

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

      bim = (struct bfd_in_memory *) abfd->iostream;
      if (abfd->where + size > bim->size)
	{
	  if (abfd->where > bim->size) {
	    size = 0;
	  } else {
	    size = bim->size - abfd->where;
	  }
	  bfd_set_error (bfd_error_file_truncated);
	}
      memcpy (ptr, bim->buffer + abfd->where, size);
      abfd->where += size;
      return size;
    }
  else if ((abfd->flags & BFD_IO_FUNCS) != 0)
    {
      struct bfd_io_functions *bif;

      bif = (struct bfd_io_functions *) abfd->iostream;
      return (*bif->read_func) (bif->iodata, ptr, 1, size, abfd, abfd->where);
    } 
  else
    {
      int nread;

      nread = fread (ptr, 1, (size_t) (size), bfd_cache_lookup(abfd));
  
      if (nread > 0)
	abfd->where += nread;
  
      /* Set bfd_error if we did not read as much data as we expected.

	 If the read failed due to an error set the bfd_error_system_call,
	 else set bfd_error_file_truncated.

	 A BFD backend may wish to override bfd_error_file_truncated to
	 provide something more useful (eg. no_symbols or wrong_format).  */

      if (nread < (int) (size))
	{
	  if (ferror (bfd_cache_lookup (abfd)))
	    bfd_set_error (bfd_error_system_call);
	  else
	    bfd_set_error (bfd_error_file_truncated);
	}

      return nread;
    }
}

bfd_size_type
bfd_bwrite (ptr, size, abfd)
     CONST PTR ptr;
     bfd_size_type size;
     bfd *abfd;
{
  while (abfd->my_archive != NULL)
    abfd = abfd->my_archive;

  if (abfd->flags & BFD_IN_MEMORY)
    {
      struct bfd_in_memory *bim = (struct bfd_in_memory *) (abfd->iostream);
      if (abfd->where + size > bim->size)
	{
	  long newsize, oldsize = (bim->size + 127) & ~127;
	  bim->size = abfd->where + size;
	  /* Round up to cut down on memory fragmentation */
	  newsize = (bim->size + 127) & ~127;
	  if (newsize > oldsize)
	    {
	      bim->buffer = bfd_realloc (bim->buffer, newsize);
	      if (bim->buffer == 0)
		{
		  bim->size = 0;
		  return 0;
		}
	    }
	}
    }
  else if ((abfd->flags & BFD_IO_FUNCS) != 0)
    {
      struct bfd_io_functions *bif;

      bif = (struct bfd_io_functions *) abfd->iostream;
      return (*bif->write_func) (bif->iodata, ptr, 1, size, abfd, abfd->where);
    } 
  else 
    {
      long nwrote;
    
      nwrote = fwrite (ptr, 1, (size_t) (size),
		       bfd_cache_lookup (abfd));
      if (nwrote > 0)
	abfd->where += nwrote;
      if ((bfd_size_type) nwrote != size)
	{
#ifdef ENOSPC
	  if (nwrote >= 0)
	    errno = ENOSPC;
#endif
	  bfd_set_error (bfd_error_system_call);
	}
      return nwrote;
    }
}

bfd_size_type
bfd_tell (abfd)
     bfd *abfd;
{
  file_ptr ptr = 0;
  bfd *cur = abfd;

  while (cur->my_archive) {
    ptr -= cur->origin;
    cur = cur->my_archive;
  }

  if ((cur->flags & BFD_IN_MEMORY) != 0)
    {
      ptr += cur->where;
    }
  else if ((abfd->flags & BFD_IO_FUNCS) != 0)
    {
      ptr += cur->where;
    } 
  else
    {
      cur->where = ftell (bfd_cache_lookup (cur));
      ptr += cur->where;
    }

  return ptr;
}

int
bfd_flush (abfd)
     bfd *abfd;
{
  while (abfd->my_archive)
    abfd = abfd->my_archive;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    {
      return 0;
    } 
  else if ((abfd->flags & BFD_IO_FUNCS) != 0)
    {
      struct bfd_io_functions *bif;

      bif = (struct bfd_io_functions *) abfd->iostream;
      return (*bif->flush_func) (bif->iodata, abfd);
    } 
  else 
    {
      return fflush (bfd_cache_lookup (abfd));
    }
}

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

  while (abfd->my_archive)
    abfd = abfd->my_archive;

  if ((abfd->flags & BFD_IN_MEMORY) != 0)
    {
      BFD_ASSERT ((abfd->flags & BFD_IN_MEMORY) == 0);
      return -1;
    } 
  else if ((abfd->flags & BFD_IO_FUNCS) != 0)
    {
      BFD_ASSERT ((abfd->flags & BFD_IO_FUNCS) == 0);
      return -1;
    } 
  else 
    {
      f = bfd_cache_lookup (abfd);
      if (f == NULL)
	{
	  bfd_set_error (bfd_error_system_call);
	  return -1;
	}
      result = fstat (fileno (f), statbuf);
      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 (abfd, position, direction)
     bfd *abfd;
     file_ptr position;
     int direction;
{
  /* 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;

  while (abfd->my_archive != NULL)
    {
      if (direction == SEEK_SET)
	position += abfd->origin;
      abfd = abfd->my_archive;
    }

  if (direction == SEEK_SET && position == abfd->where)
    return 0;

  if ((position < 0) && (direction != SEEK_CUR)) {
    bfd_set_error (bfd_error_system_call);
    return -1;
  }

  if (((abfd->flags & BFD_IN_MEMORY) != 0)
      || (abfd->flags & BFD_IO_FUNCS) != 0)
    {
      if (direction == SEEK_SET) {
	abfd->where = position;
      } else {
	abfd->where += position;
      }
      return 0;
    }
  else 
    {  
      int result;

      BFD_ASSERT (ftell (bfd_cache_lookup (abfd)) == abfd->where);

      result = fseek (bfd_cache_lookup (abfd), position, direction);
      if (result != 0)
	{
	  /* Force redetermination of `where' field.  */
	  bfd_tell (abfd);
	  bfd_set_error (bfd_error_system_call);
	}
      else
	{
	  /* Adjust `where' field.  */
	  if (direction == SEEK_SET)
	    abfd->where = position;
	  else
	    abfd->where += position;
	}

      return result;
    }
}

boolean
bfd_io_close (abfd)
     bfd *abfd;
{
  if (abfd->flags & BFD_IN_MEMORY)
    {
      int ret = 0;
      
      struct bfd_in_memory *b = (struct bfd_in_memory *) abfd->iostream;
      BFD_ASSERT (b != NULL);

#if 0
      ret = munmap (b->buffer, b->size);
#endif

      abfd->iostream = NULL;
      BFD_ASSERT (ret == 0);
      
      return true;
    } 
  else if (abfd->flags & BFD_IO_FUNCS)
    {
      struct bfd_io_functions *bif;
      
      bif = (struct bfd_io_functions *) abfd->iostream;
      return (*bif->close_func) (bif->iodata, abfd);
    }
  else
    {
      boolean ret = true;

      ret = bfd_cache_close (abfd);

      /* If the file was open for writing and is now executable,
	 make it so */
      if (ret
	  && abfd->direction == write_direction
	  && abfd->flags & EXEC_P)
	{
	  struct stat buf;

	  if (stat (abfd->filename, &buf) == 0)
	    {
	      int mask = umask (0);
	      umask (mask);
	      chmod (abfd->filename,
		     (0x777
		      & (buf.st_mode | ((S_IXUSR | S_IXGRP | S_IXOTH) &~ mask))));
	    }
	}
    }
}

/*
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 (abfd)
     bfd *abfd;
{
  while (abfd->my_archive)
    abfd = abfd->my_archive;

  if (abfd->flags & BFD_IO_FUNCS)
    {
      return 0;
    }
  else 
    {
      FILE *fp;
      struct stat buf;

      fp = bfd_cache_lookup_null (abfd);
      if (fp == NULL)
	return 0;
      if (0 != fstat (fileno (fp), &buf))
	return 0;
    
      abfd->mtime = buf.st_mtime;		/* Save value in case anyone wants it */
    
      return abfd->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 quesion, "is the
	size reasonable?".
*/

long
bfd_get_size (abfd)
     bfd *abfd;
{
  while (abfd->my_archive)
    abfd = abfd->my_archive;

  if (abfd->flags & BFD_IN_MEMORY)
    {
      return ((struct bfd_in_memory *) abfd->iostream)->size;
    } 
  else if (abfd->flags & BFD_IO_FUNCS)
    {
      return LONG_MAX;
    }
  else 
    {
      FILE *fp;
      struct stat buf;

      fp = bfd_cache_lookup (abfd);
      if (0 != fstat (fileno (fp), &buf))
	return 0;

      return buf.st_size;
    }
}