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

/* Support for memory-mapped windows into a BFD.
   Copyright 1995, 1996, 2001, 2002, 2003 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 "bfd.h"
#include "libbfd.h"

/* 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;

/* 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.  */

/*
INTERNAL_DEFINITION

.struct _bfd_window_internal {
.  struct _bfd_window_internal *next;
.  void *data;
.  bfd_size_type size;
.  int refcount : 31;		{* should be enough...  *}
.  unsigned mapped : 1;		{* 1 = mmap, 0 = malloc *}
.};
*/

void
bfd_init_window (bfd_window *windowp)
{
  windowp->data = 0;
  windowp->i = 0;
  windowp->size = 0;
}

void
bfd_free_window (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;

bfd_boolean
bfd_get_file_window (bfd *abfd,
		     file_ptr offset,
		     bfd_size_type size,
		     bfd_window *windowp,
		     bfd_boolean writable)
{
  static size_t pagesize;
  bfd_window_internal *i = windowp->i;
  bfd_size_type 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)
    {
      i = bfd_zmalloc (sizeof (bfd_window_internal));
      windowp->i = i;
      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);
      if (f == NULL)
	return FALSE;
      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 == (void *) -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)
	fprintf (stderr, "\n\tmapped %ld at %p, offset is %ld\n",
		 (long) real_size, i->data, (long) offset2);
      i->size = real_size;
      windowp->data = (bfd_byte *) i->data + offset2;
      windowp->size = size;
      i->mapped = 1;
      return TRUE;
    }
  else if (debug_windows)
    {
      if (ok_to_map)
	fprintf (stderr, _("not mapping: data=%lx mapped=%d\n"),
		 (unsigned long) i->data, (int) i->mapped);
      else
	fprintf (stderr, _("not mapping: env var not set\n"));
    }
#else
  ok_to_map = 0;
#endif

#ifdef HAVE_MPROTECT
  if (!writable)
    {
      size_to_alloc += pagesize - 1;
      size_to_alloc -= size_to_alloc % pagesize;
    }
#endif
  if (debug_windows)
    fprintf (stderr, "\n\t%s(%6ld)",
	     i->data ? "realloc" : " malloc", (long) size_to_alloc);
  i->data = bfd_realloc (i->data, size_to_alloc);
  if (debug_windows)
    fprintf (stderr, "\t-> %p\n", i->data);
  i->refcount = 1;
  if (i->data == NULL)
    {
      if (size_to_alloc == 0)
	return TRUE;
      return FALSE;
    }
  if (bfd_seek (abfd, offset, SEEK_SET) != 0)
    return FALSE;
  i->size = bfd_bread (i->data, size, abfd);
  if (i->size != size)
    return FALSE;
  i->mapped = 0;
#ifdef HAVE_MPROTECT
  if (!writable)
    {
      if (debug_windows)
	fprintf (stderr, "\tmprotect (%p, %ld, PROT_READ)\n", i->data,
		 (long) i->size);
      mprotect (i->data, i->size, PROT_READ);
    }
#endif
  windowp->data = i->data;
  windowp->size = i->size;
  return TRUE;
}

#endif /* USE_MMAP */
Commit	Line	Data
93509525	1	/* Support for memory-mapped windows into a BFD.
eac93a98	2	Copyright 1995, 1996, 2001, 2002, 2003 Free Software Foundation, Inc.
93509525 KD	3	Written by Cygnus Support.
	4
	5	This file is part of BFD, the Binary File Descriptor library.
	6
	7	This program is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 2 of the License, or
	10	(at your option) any later version.
	11
	12	This program is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with this program; if not, write to the Free Software
3e110533	19	Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
93509525 KD	20
	21	#include "sysdep.h"
	22
	23	#include "bfd.h"
	24	#include "libbfd.h"
	25
	26	/* Currently, if USE_MMAP is undefined, none if the window stuff is
	27	used. Okay, so it's mis-named. At least the command-line option
	28	"--without-mmap" is more obvious than "--without-windows" or some
	29	such. */
	30
	31	#ifdef USE_MMAP
	32
	33	#undef HAVE_MPROTECT /* code's not tested yet */
	34
	35	#if HAVE_MMAP \|\| HAVE_MPROTECT \|\| HAVE_MADVISE
	36	#include <sys/mman.h>
	37	#endif
	38
	39	#ifndef MAP_FILE
	40	#define MAP_FILE 0
	41	#endif
	42
	43	static int debug_windows;
	44
	45	/* The idea behind the next and refcount fields is that one mapped
	46	region can suffice for multiple read-only windows or multiple
	47	non-overlapping read-write windows. It's not implemented yet
	48	though. */
	49
	50	/*
	51	INTERNAL_DEFINITION
	52
	53	.struct _bfd_window_internal {
	54	. struct _bfd_window_internal *next;
c58b9523	55	. void *data;
93509525 KD	56	. bfd_size_type size;
	57	. int refcount : 31; {* should be enough... *}
	58	. unsigned mapped : 1; {* 1 = mmap, 0 = malloc *}
	59	.};
	60	*/
	61
	62	void
c58b9523	63	bfd_init_window (bfd_window *windowp)
93509525 KD	64	{
	65	windowp->data = 0;
	66	windowp->i = 0;
	67	windowp->size = 0;
	68	}
	69
	70	void
c58b9523	71	bfd_free_window (bfd_window *windowp)
93509525 KD	72	{
	73	bfd_window_internal *i = windowp->i;
	74	windowp->i = 0;
	75	windowp->data = 0;
	76	if (i == 0)
	77	return;
	78	i->refcount--;
	79	if (debug_windows)
	80	fprintf (stderr, "freeing window @%p<%p,%lx,%p>\n",
	81	windowp, windowp->data, windowp->size, windowp->i);
	82	if (i->refcount != 0)
	83	return;
	84
	85	if (i->mapped)
	86	{
	87	#ifdef HAVE_MMAP
	88	munmap (i->data, i->size);
	89	goto no_free;
	90	#else
	91	abort ();
	92	#endif
	93	}
	94	#ifdef HAVE_MPROTECT
	95	mprotect (i->data, i->size, PROT_READ \| PROT_WRITE);
	96	#endif
	97	free (i->data);
	98	#ifdef HAVE_MMAP
	99	no_free:
	100	#endif
	101	i->data = 0;
	102	/* There should be no more references to i at this point. */
	103	free (i);
	104	}
	105
	106	static int ok_to_map = 1;
	107
b34976b6	108	bfd_boolean
c58b9523 AM	109	bfd_get_file_window (bfd *abfd,
	110	file_ptr offset,
	111	bfd_size_type size,
	112	bfd_window *windowp,
	113	bfd_boolean writable)
93509525 KD	114	{
	115	static size_t pagesize;
	116	bfd_window_internal *i = windowp->i;
	117	bfd_size_type size_to_alloc = size;
	118
	119	if (debug_windows)
	120	fprintf (stderr, "bfd_get_file_window (%p, %6ld, %6ld, %p<%p,%lx,%p>, %d)",
	121	abfd, (long) offset, (long) size,
	122	windowp, windowp->data, (unsigned long) windowp->size,
	123	windowp->i, writable);
	124
	125	/* Make sure we know the page size, so we can be friendly to mmap. */
	126	if (pagesize == 0)
	127	pagesize = getpagesize ();
	128	if (pagesize == 0)
	129	abort ();
	130
	131	if (i == 0)
	132	{
c58b9523	133	i = bfd_zmalloc (sizeof (bfd_window_internal));
93509525 KD	134	windowp->i = i;
93509525 KD	135	if (i == 0)
b34976b6	136	return FALSE;
93509525 KD	137	i->data = 0;
	138	}
	139	#ifdef HAVE_MMAP
	140	if (ok_to_map
	141	&& (i->data == 0 \|\| i->mapped == 1)
	142	&& (abfd->flags & BFD_IN_MEMORY) == 0)
	143	{
	144	file_ptr file_offset, offset2;
	145	size_t real_size;
	146	int fd;
	147	FILE *f;
	148
	149	/* Find the real file and the real offset into it. */
	150	while (abfd->my_archive != NULL)
	151	{
	152	offset += abfd->origin;
	153	abfd = abfd->my_archive;
	154	}
	155	f = bfd_cache_lookup (abfd);
3dff57e8 AM	156	if (f == NULL)
3dff57e8 AM	157	return FALSE;
93509525 KD	158	fd = fileno (f);
	159
	160	/* Compute offsets and size for mmap and for the user's data. */
	161	offset2 = offset % pagesize;
	162	if (offset2 < 0)
	163	abort ();
	164	file_offset = offset - offset2;
	165	real_size = offset + size - file_offset;
	166	real_size = real_size + pagesize - 1;
	167	real_size -= real_size % pagesize;
	168
	169	/* If we're re-using a memory region, make sure it's big enough. */
	170	if (i->data && i->size < size)
	171	{
	172	munmap (i->data, i->size);
	173	i->data = 0;
	174	}
	175	i->data = mmap (i->data, real_size,
	176	writable ? PROT_WRITE \| PROT_READ : PROT_READ,
	177	(writable
	178	? MAP_FILE \| MAP_PRIVATE
	179	: MAP_FILE \| MAP_SHARED),
	180	fd, file_offset);
c58b9523	181	if (i->data == (void *) -1)
93509525 KD	182	{
	183	/* An error happened. Report it, or try using malloc, or
	184	something. */
	185	bfd_set_error (bfd_error_system_call);
	186	i->data = 0;
	187	windowp->data = 0;
	188	if (debug_windows)
	189	fprintf (stderr, "\t\tmmap failed!\n");
b34976b6	190	return FALSE;
93509525 KD	191	}
	192	if (debug_windows)
	193	fprintf (stderr, "\n\tmapped %ld at %p, offset is %ld\n",
	194	(long) real_size, i->data, (long) offset2);
	195	i->size = real_size;
c58b9523	196	windowp->data = (bfd_byte *) i->data + offset2;
93509525 KD	197	windowp->size = size;
93509525 KD	198	i->mapped = 1;
b34976b6	199	return TRUE;
93509525 KD	200	}
	201	else if (debug_windows)
	202	{
	203	if (ok_to_map)
	204	fprintf (stderr, _("not mapping: data=%lx mapped=%d\n"),
	205	(unsigned long) i->data, (int) i->mapped);
	206	else
	207	fprintf (stderr, _("not mapping: env var not set\n"));
	208	}
	209	#else
	210	ok_to_map = 0;
	211	#endif
	212
	213	#ifdef HAVE_MPROTECT
	214	if (!writable)
	215	{
	216	size_to_alloc += pagesize - 1;
	217	size_to_alloc -= size_to_alloc % pagesize;
	218	}
	219	#endif
	220	if (debug_windows)
	221	fprintf (stderr, "\n\t%s(%6ld)",
	222	i->data ? "realloc" : " malloc", (long) size_to_alloc);
c58b9523	223	i->data = bfd_realloc (i->data, size_to_alloc);
93509525 KD	224	if (debug_windows)
	225	fprintf (stderr, "\t-> %p\n", i->data);
	226	i->refcount = 1;
	227	if (i->data == NULL)
	228	{
	229	if (size_to_alloc == 0)
b34976b6 AM	230	return TRUE;
b34976b6 AM	231	return FALSE;
93509525 KD	232	}
93509525 KD	233	if (bfd_seek (abfd, offset, SEEK_SET) != 0)
b34976b6	234	return FALSE;
93509525 KD	235	i->size = bfd_bread (i->data, size, abfd);
93509525 KD	236	if (i->size != size)
b34976b6	237	return FALSE;
93509525 KD	238	i->mapped = 0;
	239	#ifdef HAVE_MPROTECT
	240	if (!writable)
	241	{
	242	if (debug_windows)
	243	fprintf (stderr, "\tmprotect (%p, %ld, PROT_READ)\n", i->data,
	244	(long) i->size);
	245	mprotect (i->data, i->size, PROT_READ);
	246	}
	247	#endif
	248	windowp->data = i->data;
	249	windowp->size = i->size;
b34976b6	250	return TRUE;
93509525 KD	251	}
	252
	253	#endif /* USE_MMAP */