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

/* Support for memory-mapped windows into a BFD.
   Copyright 1995, 1996, 2001, 2002 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 "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;
.  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;
}

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;

bfd_boolean
bfd_get_file_window (abfd, offset, size, windowp, writable)
     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_window_internal *)
	   bfd_zmalloc ((bfd_size_type) 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);
      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)
	fprintf (stderr, "\n\tmapped %ld at %p, offset is %ld\n",
		 (long) real_size, i->data, (long) offset2);
      i->size = real_size;
      windowp->data = (PTR) ((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 = (PTR) 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 KD	1	/* Support for memory-mapped windows into a BFD.
	2	Copyright 1995, 1996, 2001, 2002 Free Software Foundation, Inc.
	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
	19	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
	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;
	55	. PTR data;
	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
	63	bfd_init_window (windowp)
	64	bfd_window *windowp;
65	{
66	windowp->data = 0;
67	windowp->i = 0;
68	windowp->size = 0;
69	}
70
71	void
72	bfd_free_window (windowp)
73	bfd_window *windowp;
74	{
75	bfd_window_internal *i = windowp->i;
76	windowp->i = 0;
77	windowp->data = 0;
78	if (i == 0)
79	return;
80	i->refcount--;
81	if (debug_windows)
82	fprintf (stderr, "freeing window @%p<%p,%lx,%p>\n",
83	windowp, windowp->data, windowp->size, windowp->i);
84	if (i->refcount != 0)
85	return;
86
87	if (i->mapped)
88	{
89	#ifdef HAVE_MMAP
90	munmap (i->data, i->size);
91	goto no_free;
92	#else
93	abort ();
94	#endif
95	}
96	#ifdef HAVE_MPROTECT
97	mprotect (i->data, i->size, PROT_READ \| PROT_WRITE);
98	#endif
99	free (i->data);
100	#ifdef HAVE_MMAP
101	no_free:
102	#endif
103	i->data = 0;
104	/* There should be no more references to i at this point. */
105	free (i);
106	}
107
108	static int ok_to_map = 1;
109
b34976b6	110	bfd_boolean
93509525 KD	111	bfd_get_file_window (abfd, offset, size, windowp, writable)
	112	bfd *abfd;
	113	file_ptr offset;
	114	bfd_size_type size;
	115	bfd_window *windowp;
b34976b6	116	bfd_boolean writable;
93509525 KD	117	{
	118	static size_t pagesize;
	119	bfd_window_internal *i = windowp->i;
	120	bfd_size_type size_to_alloc = size;
	121
	122	if (debug_windows)
	123	fprintf (stderr, "bfd_get_file_window (%p, %6ld, %6ld, %p<%p,%lx,%p>, %d)",
	124	abfd, (long) offset, (long) size,
	125	windowp, windowp->data, (unsigned long) windowp->size,
	126	windowp->i, writable);
	127
	128	/* Make sure we know the page size, so we can be friendly to mmap. */
	129	if (pagesize == 0)
	130	pagesize = getpagesize ();
	131	if (pagesize == 0)
	132	abort ();
	133
	134	if (i == 0)
	135	{
	136	i = ((bfd_window_internal *)
	137	bfd_zmalloc ((bfd_size_type) sizeof (bfd_window_internal)));
	138	windowp->i = i;
	139	if (i == 0)
b34976b6	140	return FALSE;
93509525 KD	141	i->data = 0;
	142	}
	143	#ifdef HAVE_MMAP
	144	if (ok_to_map
	145	&& (i->data == 0 \|\| i->mapped == 1)
	146	&& (abfd->flags & BFD_IN_MEMORY) == 0)
	147	{
	148	file_ptr file_offset, offset2;
	149	size_t real_size;
	150	int fd;
	151	FILE *f;
	152
	153	/* Find the real file and the real offset into it. */
	154	while (abfd->my_archive != NULL)
	155	{
	156	offset += abfd->origin;
	157	abfd = abfd->my_archive;
	158	}
	159	f = bfd_cache_lookup (abfd);
	160	fd = fileno (f);
	161
	162	/* Compute offsets and size for mmap and for the user's data. */
	163	offset2 = offset % pagesize;
	164	if (offset2 < 0)
	165	abort ();
	166	file_offset = offset - offset2;
	167	real_size = offset + size - file_offset;
	168	real_size = real_size + pagesize - 1;
	169	real_size -= real_size % pagesize;
	170
	171	/* If we're re-using a memory region, make sure it's big enough. */
	172	if (i->data && i->size < size)
	173	{
	174	munmap (i->data, i->size);
	175	i->data = 0;
	176	}
	177	i->data = mmap (i->data, real_size,
	178	writable ? PROT_WRITE \| PROT_READ : PROT_READ,
	179	(writable
	180	? MAP_FILE \| MAP_PRIVATE
	181	: MAP_FILE \| MAP_SHARED),
	182	fd, file_offset);
	183	if (i->data == (PTR) -1)
	184	{
	185	/* An error happened. Report it, or try using malloc, or
	186	something. */
	187	bfd_set_error (bfd_error_system_call);
	188	i->data = 0;
	189	windowp->data = 0;
	190	if (debug_windows)
	191	fprintf (stderr, "\t\tmmap failed!\n");
b34976b6	192	return FALSE;
93509525 KD	193	}
	194	if (debug_windows)
	195	fprintf (stderr, "\n\tmapped %ld at %p, offset is %ld\n",
	196	(long) real_size, i->data, (long) offset2);
	197	i->size = real_size;
	198	windowp->data = (PTR) ((bfd_byte *) i->data + offset2);
	199	windowp->size = size;
	200	i->mapped = 1;
b34976b6	201	return TRUE;
93509525 KD	202	}
	203	else if (debug_windows)
	204	{
	205	if (ok_to_map)
	206	fprintf (stderr, _("not mapping: data=%lx mapped=%d\n"),
	207	(unsigned long) i->data, (int) i->mapped);
	208	else
	209	fprintf (stderr, _("not mapping: env var not set\n"));
	210	}
	211	#else
	212	ok_to_map = 0;
	213	#endif
	214
	215	#ifdef HAVE_MPROTECT
	216	if (!writable)
	217	{
	218	size_to_alloc += pagesize - 1;
	219	size_to_alloc -= size_to_alloc % pagesize;
	220	}
	221	#endif
	222	if (debug_windows)
	223	fprintf (stderr, "\n\t%s(%6ld)",
	224	i->data ? "realloc" : " malloc", (long) size_to_alloc);
	225	i->data = (PTR) bfd_realloc (i->data, size_to_alloc);
	226	if (debug_windows)
	227	fprintf (stderr, "\t-> %p\n", i->data);
	228	i->refcount = 1;
	229	if (i->data == NULL)
	230	{
	231	if (size_to_alloc == 0)
b34976b6 AM	232	return TRUE;
b34976b6 AM	233	return FALSE;
93509525 KD	234	}
93509525 KD	235	if (bfd_seek (abfd, offset, SEEK_SET) != 0)
b34976b6	236	return FALSE;
93509525 KD	237	i->size = bfd_bread (i->data, size, abfd);
93509525 KD	238	if (i->size != size)
b34976b6	239	return FALSE;
93509525 KD	240	i->mapped = 0;
	241	#ifdef HAVE_MPROTECT
	242	if (!writable)
	243	{
	244	if (debug_windows)
	245	fprintf (stderr, "\tmprotect (%p, %ld, PROT_READ)\n", i->data,
	246	(long) i->size);
	247	mprotect (i->data, i->size, PROT_READ);
	248	}
	249	#endif
	250	windowp->data = i->data;
	251	windowp->size = i->size;
b34976b6	252	return TRUE;
93509525 KD	253	}
	254
	255	#endif /* USE_MMAP */