1 /* Support for memory-mapped windows into a BFD.
2 Copyright 1995, 1996, 2001, 2002, 2003, 2005, 2007, 2008, 2009
3 Free Software Foundation, Inc.
4 Written by Cygnus Support.
6 This file is part of BFD, the Binary File Descriptor library.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 MA 02110-1301, USA. */
28 /* Currently, if USE_MMAP is undefined, none of the window stuff is
29 used. Enabled by --with-mmap. */
33 #undef HAVE_MPROTECT /* code's not tested yet */
35 #if HAVE_MMAP || HAVE_MPROTECT || HAVE_MADVISE
43 static int debug_windows
;
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
53 .struct _bfd_window_internal {
54 . struct _bfd_window_internal *next;
57 . int refcount : 31; {* should be enough... *}
58 . unsigned mapped : 1; {* 1 = mmap, 0 = malloc *}
63 bfd_init_window (bfd_window
*windowp
)
71 bfd_free_window (bfd_window
*windowp
)
73 bfd_window_internal
*i
= windowp
->i
;
80 fprintf (stderr
, "freeing window @%p<%p,%lx,%p>\n",
81 windowp
, windowp
->data
, (unsigned long) windowp
->size
, windowp
->i
);
88 munmap (i
->data
, i
->size
);
95 mprotect (i
->data
, i
->size
, PROT_READ
| PROT_WRITE
);
102 /* There should be no more references to i at this point. */
106 static int ok_to_map
= 1;
109 bfd_get_file_window (bfd
*abfd
,
113 bfd_boolean writable
)
115 static size_t pagesize
;
116 bfd_window_internal
*i
= windowp
->i
;
117 bfd_size_type size_to_alloc
= size
;
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
);
125 /* Make sure we know the page size, so we can be friendly to mmap. */
127 pagesize
= getpagesize ();
133 i
= bfd_zmalloc (sizeof (bfd_window_internal
));
141 && (i
->data
== 0 || i
->mapped
== 1)
142 && (abfd
->flags
& BFD_IN_MEMORY
) == 0)
144 file_ptr file_offset
, offset2
;
148 /* Find the real file and the real offset into it. */
149 while (abfd
->my_archive
!= NULL
)
151 offset
+= abfd
->origin
;
152 abfd
= abfd
->my_archive
;
155 /* Seek into the file, to ensure it is open if cacheable. */
156 if (abfd
->iostream
== NULL
157 && (abfd
->iovec
== NULL
158 || abfd
->iovec
->bseek (abfd
, offset
, SEEK_SET
) != 0))
160 fd
= fileno ((FILE *) abfd
->iostream
);
162 /* Compute offsets and size for mmap and for the user's data. */
163 offset2
= offset
% pagesize
;
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
;
171 /* If we're re-using a memory region, make sure it's big enough. */
172 if (i
->data
&& i
->size
< size
)
174 munmap (i
->data
, i
->size
);
177 i
->data
= mmap (i
->data
, real_size
,
178 writable
? PROT_WRITE
| PROT_READ
: PROT_READ
,
180 ? MAP_FILE
| MAP_PRIVATE
181 : MAP_FILE
| MAP_SHARED
),
183 if (i
->data
== (void *) -1)
185 /* An error happened. Report it, or try using malloc, or
187 bfd_set_error (bfd_error_system_call
);
191 fprintf (stderr
, "\t\tmmap failed!\n");
195 fprintf (stderr
, "\n\tmapped %ld at %p, offset is %ld\n",
196 (long) real_size
, i
->data
, (long) offset2
);
198 windowp
->data
= (bfd_byte
*) i
->data
+ offset2
;
199 windowp
->size
= size
;
203 else if (debug_windows
)
206 fprintf (stderr
, _("not mapping: data=%lx mapped=%d\n"),
207 (unsigned long) i
->data
, (int) i
->mapped
);
209 fprintf (stderr
, _("not mapping: env var not set\n"));
218 size_to_alloc
+= pagesize
- 1;
219 size_to_alloc
-= size_to_alloc
% pagesize
;
223 fprintf (stderr
, "\n\t%s(%6ld)",
224 i
->data
? "realloc" : " malloc", (long) size_to_alloc
);
225 i
->data
= bfd_realloc_or_free (i
->data
, size_to_alloc
);
227 fprintf (stderr
, "\t-> %p\n", i
->data
);
230 if (size_to_alloc
== 0)
235 if (bfd_seek (abfd
, offset
, SEEK_SET
) != 0)
237 i
->size
= bfd_bread (i
->data
, size
, abfd
);
245 fprintf (stderr
, "\tmprotect (%p, %ld, PROT_READ)\n", i
->data
,
247 mprotect (i
->data
, i
->size
, PROT_READ
);
250 windowp
->data
= i
->data
;
251 windowp
->size
= i
->size
;
255 #endif /* USE_MMAP */