libbfd.c

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/* Assorted BFD support routines, only used internally.
   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001
   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 "bfd.h"
#include "sysdep.h"
#include "libbfd.h"

#ifndef HAVE_GETPAGESIZE
#define getpagesize() 2048
#endif

static int real_read PARAMS ((PTR, size_t, size_t, FILE *));

/*
SECTION
	Internal functions

DESCRIPTION
	These routines are used within BFD.
	They are not intended for export, but are documented here for
	completeness.
*/

/* A routine which is used in target vectors for unsupported
   operations.  */

boolean
bfd_false (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_invalid_operation);
  return false;
}

/* A routine which is used in target vectors for supported operations
   which do not actually do anything.  */

boolean
bfd_true (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
  return true;
}

/* A routine which is used in target vectors for unsupported
   operations which return a pointer value.  */

PTR
bfd_nullvoidptr (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_invalid_operation);
  return NULL;
}

int
bfd_0 (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
  return 0;
}

unsigned int
bfd_0u (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
   return 0;
}

long
bfd_0l (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
  return 0;
}

/* A routine which is used in target vectors for unsupported
   operations which return -1 on error.  */

long
_bfd_n1 (ignore_abfd)
     bfd *ignore_abfd ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_invalid_operation);
  return -1;
}

void
bfd_void (ignore)
     bfd *ignore ATTRIBUTE_UNUSED;
{
}

boolean
_bfd_nocore_core_file_matches_executable_p (ignore_core_bfd, ignore_exec_bfd)
     bfd *ignore_core_bfd ATTRIBUTE_UNUSED;
     bfd *ignore_exec_bfd ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_invalid_operation);
  return false;
}

/* Routine to handle core_file_failing_command entry point for targets
   without core file support.  */

char *
_bfd_nocore_core_file_failing_command (ignore_abfd)
     bfd *ignore_abfd ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_invalid_operation);
  return (char *)NULL;
}

/* Routine to handle core_file_failing_signal entry point for targets
   without core file support.  */

int
_bfd_nocore_core_file_failing_signal (ignore_abfd)
     bfd *ignore_abfd ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_invalid_operation);
  return 0;
}

const bfd_target *
_bfd_dummy_target (ignore_abfd)
     bfd *ignore_abfd ATTRIBUTE_UNUSED;
{
  bfd_set_error (bfd_error_wrong_format);
  return 0;
}

/* Allocate memory using malloc.  */

PTR
bfd_malloc (size)
     size_t size;
{
  PTR ptr;

  ptr = (PTR) malloc (size);
  if (ptr == NULL && size != 0)
    bfd_set_error (bfd_error_no_memory);
  return ptr;
}

/* Reallocate memory using realloc.  */

PTR
bfd_realloc (ptr, size)
     PTR ptr;
     size_t size;
{
  PTR ret;

  if (ptr == NULL)
    ret = malloc (size);
  else
    ret = realloc (ptr, size);

  if (ret == NULL)
    bfd_set_error (bfd_error_no_memory);

  return ret;
}

/* Allocate memory using malloc and clear it.  */

PTR
bfd_zmalloc (size)
     size_t size;
{
  PTR ptr;

  ptr = (PTR) malloc (size);

  if (size != 0)
    {
      if (ptr == NULL)
	bfd_set_error (bfd_error_no_memory);
      else
	memset (ptr, 0, size);
    }

  return ptr;
}

/* Some IO code */

/* 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.  */

static int
real_read (where, a,b, file)
     PTR where;
     size_t a;
     size_t b;
     FILE *file;
{
  /* FIXME - this looks like an optimization, but it's really to cover
     up for a feature of some OSs (not solaris - sigh) that
     ld/pe-dll.c takes advantage of (apparently) when it creates BFDs
     internally and tries to link against them.  BFD seems to be smart
     enough to realize there are no symbol records in the "file" that
     doesn't exist but attempts to read them anyway.  On Solaris,
     attempting to read zero bytes from a NULL file results in a core
     dump, but on other platforms it just returns zero bytes read.
     This makes it to something reasonable. - DJ */
  if (a == 0 || b == 0)
    return 0;


#if defined (__VAX) && defined (VMS)
  /* Apparently fread on Vax VMS does not keep the record length
     information.  */
  return read (fileno (file), where, a * b);
#else
  return fread (where, a, b, file);
#endif
}

/* 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_read (ptr, size, nitems, abfd)
     PTR ptr;
     bfd_size_type size;
     bfd_size_type nitems;
     bfd *abfd;
{
  int nread;

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

      bim = (struct bfd_in_memory *) abfd->iostream;
      get = size * nitems;
      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, get);
      abfd->where += get;
      return get;
    }

  nread = real_read (ptr, 1, (size_t) (size*nitems), 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 * nitems))
    {
      if (ferror (bfd_cache_lookup (abfd)))
	bfd_set_error (bfd_error_system_call);
      else
	bfd_set_error (bfd_error_file_truncated);
    }

  return nread;
}

/* The window support stuff should probably be broken out into
   another file....  */
/* The idea behind the next and refcount fields is that one mapped
   region can suffice for multiple read-only windows or multiple
   non-overlapping read-write windows.  It's not implemented yet
   though.  */
struct _bfd_window_internal {
  struct _bfd_window_internal *next;
  PTR data;
  bfd_size_type size;
  int refcount : 31;		/* should be enough...  */
  unsigned mapped : 1;		/* 1 = mmap, 0 = malloc */
};

void
bfd_init_window (windowp)
     bfd_window *windowp;
{
  windowp->data = 0;
  windowp->i = 0;
  windowp->size = 0;
}

/* Currently, if USE_MMAP is undefined, none if the window stuff is
   used.  Okay, so it's mis-named.  At least the command-line option
   "--without-mmap" is more obvious than "--without-windows" or some
   such.  */
#ifdef USE_MMAP

#undef HAVE_MPROTECT /* code's not tested yet */

#if HAVE_MMAP || HAVE_MPROTECT || HAVE_MADVISE
#include <sys/mman.h>
#endif

#ifndef MAP_FILE
#define MAP_FILE 0
#endif

static int debug_windows;

void
bfd_free_window (windowp)
     bfd_window *windowp;
{
  bfd_window_internal *i = windowp->i;
  windowp->i = 0;
  windowp->data = 0;
  if (i == 0)
    return;
  i->refcount--;
  if (debug_windows)
    fprintf (stderr, "freeing window @%p<%p,%lx,%p>\n",
	     windowp, windowp->data, windowp->size, windowp->i);
  if (i->refcount != 0)
    return;

  if (i->mapped)
    {
#ifdef HAVE_MMAP
      munmap (i->data, i->size);
      goto no_free;
#else
      abort ();
#endif
    }
#ifdef HAVE_MPROTECT
  mprotect (i->data, i->size, PROT_READ | PROT_WRITE);
#endif
  free (i->data);
#ifdef HAVE_MMAP
 no_free:
#endif
  i->data = 0;
  /* There should be no more references to i at this point.  */
  free (i);
}

static int ok_to_map = 1;

boolean
bfd_get_file_window (abfd, offset, size, windowp, writable)
     bfd *abfd;
     file_ptr offset;
     bfd_size_type size;
     bfd_window *windowp;
     boolean writable;
{
  static size_t pagesize;
  bfd_window_internal *i = windowp->i;
  size_t size_to_alloc = size;

  if (debug_windows)
    fprintf (stderr, "bfd_get_file_window (%p, %6ld, %6ld, %p<%p,%lx,%p>, %d)",
	     abfd, (long) offset, (long) size,
	     windowp, windowp->data, (unsigned long) windowp->size,
	     windowp->i, writable);

  /* Make sure we know the page size, so we can be friendly to mmap.  */
  if (pagesize == 0)
    pagesize = getpagesize ();
  if (pagesize == 0)
    abort ();

  if (i == 0)
    {
      windowp->i = i = (bfd_window_internal *) bfd_zmalloc (sizeof (bfd_window_internal));
      if (i == 0)
	return false;
      i->data = 0;
    }
#ifdef HAVE_MMAP
  if (ok_to_map
      && (i->data == 0 || i->mapped == 1)
      && (abfd->flags & BFD_IN_MEMORY) == 0)
    {
      file_ptr file_offset, offset2;
      size_t real_size;
      int fd;
      FILE *f;

      /* Find the real file and the real offset into it.  */
      while (abfd->my_archive != NULL)
	{
	  offset += abfd->origin;
	  abfd = abfd->my_archive;
	}
      f = bfd_cache_lookup (abfd);
      fd = fileno (f);

      /* Compute offsets and size for mmap and for the user's data.  */
      offset2 = offset % pagesize;
      if (offset2 < 0)
	abort ();
      file_offset = offset - offset2;
      real_size = offset + size - file_offset;
      real_size = real_size + pagesize - 1;
      real_size -= real_size % pagesize;

      /* If we're re-using a memory region, make sure it's big enough.  */
      if (i->data && i->size < size)
	{
	  munmap (i->data, i->size);
	  i->data = 0;
	}
      i->data = mmap (i->data, real_size,
		      writable ? PROT_WRITE | PROT_READ : PROT_READ,
		      (writable
		       ? MAP_FILE | MAP_PRIVATE
		       : MAP_FILE | MAP_SHARED),
		      fd, file_offset);
      if (i->data == (PTR) -1)
	{
	  /* An error happened.  Report it, or try using malloc, or
	     something.  */
	  bfd_set_error (bfd_error_system_call);
	  i->data = 0;
	  windowp->data = 0;
	  if (debug_windows)
	    fprintf (stderr, "\t\tmmap failed!\n");
	  return false;
	}
      if (debug_windows)