1 /* $MirOS: src/gnu/usr.bin/binutils/bfd/bfdwin.c,v 1.3 2005/06/05 21:23:53 tg Exp $ */
2 
3 /* Support for memory-mapped windows into a BFD.
4    Copyright 1995, 1996, 2001, 2002, 2003 Free Software Foundation, Inc.
5    Written by Cygnus Support.
6 
7 This file is part of BFD, the Binary File Descriptor library.
8 
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
13 
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 GNU General Public License for more details.
18 
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
22 
23 #include "sysdep.h"
24 
25 #include "bfd.h"
26 #include "libbfd.h"
27 
28 __RCSID("$MirOS: src/gnu/usr.bin/binutils/bfd/bfdwin.c,v 1.3 2005/06/05 21:23:53 tg Exp $");
29 
30 /* Currently, if USE_MMAP is undefined, none if the window stuff is
31    used.  Okay, so it's mis-named.  At least the command-line option
32    "--without-mmap" is more obvious than "--without-windows" or some
33    such.  */
34 
35 #ifdef USE_MMAP
36 
37 #undef HAVE_MPROTECT /* code's not tested yet */
38 
39 #if HAVE_MMAP || HAVE_MPROTECT || HAVE_MADVISE
40 #include <sys/mman.h>
41 #endif
42 
43 #ifndef MAP_FILE
44 #define MAP_FILE 0
45 #endif
46 
47 static int debug_windows;
48 
49 /* The idea behind the next and refcount fields is that one mapped
50    region can suffice for multiple read-only windows or multiple
51    non-overlapping read-write windows.  It's not implemented yet
52    though.  */
53 
54 /*
55 INTERNAL_DEFINITION
56 
57 .struct _bfd_window_internal {
58 .  struct _bfd_window_internal *next;
59 .  void *data;
60 .  bfd_size_type size;
61 .  int refcount : 31;		{* should be enough...  *}
62 .  unsigned mapped : 1;		{* 1 = mmap, 0 = malloc *}
63 .};
64 */
65 
66 void
bfd_init_window(bfd_window * windowp)67 bfd_init_window (bfd_window *windowp)
68 {
69   windowp->data = 0;
70   windowp->i = 0;
71   windowp->size = 0;
72 }
73 
74 void
bfd_free_window(bfd_window * windowp)75 bfd_free_window (bfd_window *windowp)
76 {
77   bfd_window_internal *i = windowp->i;
78   windowp->i = 0;
79   windowp->data = 0;
80   if (i == 0)
81     return;
82   i->refcount--;
83   if (debug_windows)
84     fprintf (stderr, "freeing window @%p<%p,%lx,%p>\n",
85 	     windowp, windowp->data, (unsigned long)windowp->size, windowp->i);
86   if (i->refcount != 0)
87     return;
88 
89   if (i->mapped)
90     {
91 #ifdef HAVE_MMAP
92       munmap (i->data, i->size);
93       goto no_free;
94 #else
95       abort ();
96 #endif
97     }
98 #ifdef HAVE_MPROTECT
99   mprotect (i->data, i->size, PROT_READ | PROT_WRITE);
100 #endif
101   free (i->data);
102 #ifdef HAVE_MMAP
103  no_free:
104 #endif
105   i->data = 0;
106   /* There should be no more references to i at this point.  */
107   free (i);
108 }
109 
110 static int ok_to_map = 1;
111 
112 bfd_boolean
bfd_get_file_window(bfd * abfd,file_ptr offset,bfd_size_type size,bfd_window * windowp,bfd_boolean writable)113 bfd_get_file_window (bfd *abfd,
114 		     file_ptr offset,
115 		     bfd_size_type size,
116 		     bfd_window *windowp,
117 		     bfd_boolean writable)
118 {
119   static size_t pagesize;
120   bfd_window_internal *i = windowp->i;
121   bfd_size_type size_to_alloc = size;
122 
123   if (debug_windows)
124     fprintf (stderr, "bfd_get_file_window (%p, %6ld, %6ld, %p<%p,%lx,%p>, %d)",
125 	     abfd, (long) offset, (long) size,
126 	     windowp, windowp->data, (unsigned long) windowp->size,
127 	     windowp->i, writable);
128 
129   /* Make sure we know the page size, so we can be friendly to mmap.  */
130   if (pagesize == 0)
131     pagesize = getpagesize ();
132   if (pagesize == 0)
133     abort ();
134 
135   if (i == 0)
136     {
137       i = bfd_zmalloc (sizeof (bfd_window_internal));
138       windowp->i = i;
139       if (i == 0)
140 	return FALSE;
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 == (void *) -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");
192 	  return FALSE;
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 = (bfd_byte *) i->data + offset2;
199       windowp->size = size;
200       i->mapped = 1;
201       return TRUE;
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 = 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)
232 	return TRUE;
233       return FALSE;
234     }
235   if (bfd_seek (abfd, offset, SEEK_SET) != 0)
236     return FALSE;
237   i->size = bfd_bread (i->data, size, abfd);
238   if (i->size != size)
239     return FALSE;
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;
252   return TRUE;
253 }
254 
255 #endif /* USE_MMAP */
256