1/* Support for memory-mapped windows into a BFD. 2 Copyright 1995, 1996, 2001, 2002, 2003, 2005 3 Free Software Foundation, Inc. 4 Written by Cygnus Support. 5 6This file is part of BFD, the Binary File Descriptor library. 7 8This program is free software; you can redistribute it and/or modify 9it under the terms of the GNU General Public License as published by 10the Free Software Foundation; either version 2 of the License, or 11(at your option) any later version. 12 13This program is distributed in the hope that it will be useful, 14but WITHOUT ANY WARRANTY; without even the implied warranty of 15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16GNU General Public License for more details. 17 18You should have received a copy of the GNU General Public License 19along with this program; if not, write to the Free Software 20Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ 21 22#include "sysdep.h" 23 24#include "bfd.h" 25#include "libbfd.h" 26 27/* Currently, if USE_MMAP is undefined, none if the window stuff is 28 used. Okay, so it's mis-named. At least the command-line option 29 "--without-mmap" is more obvious than "--without-windows" or some 30 such. */ 31 32#ifdef USE_MMAP 33 34#undef HAVE_MPROTECT /* code's not tested yet */ 35 36#if HAVE_MMAP || HAVE_MPROTECT || HAVE_MADVISE 37#include <sys/mman.h> 38#endif 39 40#ifndef MAP_FILE 41#define MAP_FILE 0 42#endif 43 44static int debug_windows; 45 46/* The idea behind the next and refcount fields is that one mapped 47 region can suffice for multiple read-only windows or multiple 48 non-overlapping read-write windows. It's not implemented yet 49 though. */ 50 51/* 52INTERNAL_DEFINITION 53 54.struct _bfd_window_internal { 55. struct _bfd_window_internal *next; 56. void *data; 57. bfd_size_type size; 58. int refcount : 31; {* should be enough... *} 59. unsigned mapped : 1; {* 1 = mmap, 0 = malloc *} 60.}; 61*/ 62 63void 64bfd_init_window (bfd_window *windowp) 65{ 66 windowp->data = 0; 67 windowp->i = 0; 68 windowp->size = 0; 69} 70 71void 72bfd_free_window (bfd_window *windowp) 73{ 74 bfd_window_internal *i = windowp->i; 75 windowp->i = 0; 76 windowp->data = 0; 77 if (i == 0) 78 return; 79 i->refcount--; 80 if (debug_windows) 81 fprintf (stderr, "freeing window @%p<%p,%lx,%p>\n", 82 windowp, windowp->data, windowp->size, windowp->i); 83 if (i->refcount != 0) 84 return; 85 86 if (i->mapped) 87 { 88#ifdef HAVE_MMAP 89 munmap (i->data, i->size); 90 goto no_free; 91#else 92 abort (); 93#endif 94 } 95#ifdef HAVE_MPROTECT 96 mprotect (i->data, i->size, PROT_READ | PROT_WRITE); 97#endif 98 free (i->data); 99#ifdef HAVE_MMAP 100 no_free: 101#endif 102 i->data = 0; 103 /* There should be no more references to i at this point. */ 104 free (i); 105} 106 107static int ok_to_map = 1; 108 109bfd_boolean 110bfd_get_file_window (bfd *abfd, 111 file_ptr offset, 112 bfd_size_type size, 113 bfd_window *windowp, 114 bfd_boolean writable) 115{ 116 static size_t pagesize; 117 bfd_window_internal *i = windowp->i; 118 bfd_size_type size_to_alloc = size; 119 120 if (debug_windows) 121 fprintf (stderr, "bfd_get_file_window (%p, %6ld, %6ld, %p<%p,%lx,%p>, %d)", 122 abfd, (long) offset, (long) size, 123 windowp, windowp->data, (unsigned long) windowp->size, 124 windowp->i, writable); 125 126 /* Make sure we know the page size, so we can be friendly to mmap. */ 127 if (pagesize == 0) 128 pagesize = getpagesize (); 129 if (pagesize == 0) 130 abort (); 131 132 if (i == 0) 133 { 134 i = bfd_zmalloc (sizeof (bfd_window_internal)); 135 windowp->i = i; 136 if (i == 0) 137 return FALSE; 138 i->data = 0; 139 } 140#ifdef HAVE_MMAP 141 if (ok_to_map 142 && (i->data == 0 || i->mapped == 1) 143 && (abfd->flags & BFD_IN_MEMORY) == 0) 144 { 145 file_ptr file_offset, offset2; 146 size_t real_size; 147 int fd; 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 } 155 156 /* Seek into the file, to ensure it is open if cacheable. */ 157 if (abfd->iostream == NULL 158 && (abfd->iovec == NULL 159 || abfd->iovec->bseek (abfd, offset, SEEK_SET) != 0)) 160 return FALSE; 161 fd = fileno ((FILE *) abfd->iostream); 162 163 /* Compute offsets and size for mmap and for the user's data. */ 164 offset2 = offset % pagesize; 165 if (offset2 < 0) 166 abort (); 167 file_offset = offset - offset2; 168 real_size = offset + size - file_offset; 169 real_size = real_size + pagesize - 1; 170 real_size -= real_size % pagesize; 171 172 /* If we're re-using a memory region, make sure it's big enough. */ 173 if (i->data && i->size < size) 174 { 175 munmap (i->data, i->size); 176 i->data = 0; 177 } 178 i->data = mmap (i->data, real_size, 179 writable ? PROT_WRITE | PROT_READ : PROT_READ, 180 (writable 181 ? MAP_FILE | MAP_PRIVATE 182 : MAP_FILE | MAP_SHARED), 183 fd, file_offset); 184 if (i->data == (void *) -1) 185 { 186 /* An error happened. Report it, or try using malloc, or 187 something. */ 188 bfd_set_error (bfd_error_system_call); 189 i->data = 0; 190 windowp->data = 0; 191 if (debug_windows) 192 fprintf (stderr, "\t\tmmap failed!\n"); 193 return FALSE; 194 } 195 if (debug_windows) 196 fprintf (stderr, "\n\tmapped %ld at %p, offset is %ld\n", 197 (long) real_size, i->data, (long) offset2); 198 i->size = real_size; 199 windowp->data = (bfd_byte *) i->data + offset2; 200 windowp->size = size; 201 i->mapped = 1; 202 return TRUE; 203 } 204 else if (debug_windows) 205 { 206 if (ok_to_map) 207 fprintf (stderr, _("not mapping: data=%lx mapped=%d\n"), 208 (unsigned long) i->data, (int) i->mapped); 209 else 210 fprintf (stderr, _("not mapping: env var not set\n")); 211 } 212#else 213 ok_to_map = 0; 214#endif 215 216#ifdef HAVE_MPROTECT 217 if (!writable) 218 { 219 size_to_alloc += pagesize - 1; 220 size_to_alloc -= size_to_alloc % pagesize; 221 } 222#endif 223 if (debug_windows) 224 fprintf (stderr, "\n\t%s(%6ld)", 225 i->data ? "realloc" : " malloc", (long) size_to_alloc); 226 i->data = bfd_realloc (i->data, size_to_alloc); 227 if (debug_windows) 228 fprintf (stderr, "\t-> %p\n", i->data); 229 i->refcount = 1; 230 if (i->data == NULL) 231 { 232 if (size_to_alloc == 0) 233 return TRUE; 234 return FALSE; 235 } 236 if (bfd_seek (abfd, offset, SEEK_SET) != 0) 237 return FALSE; 238 i->size = bfd_bread (i->data, size, abfd); 239 if (i->size != size) 240 return FALSE; 241 i->mapped = 0; 242#ifdef HAVE_MPROTECT 243 if (!writable) 244 { 245 if (debug_windows) 246 fprintf (stderr, "\tmprotect (%p, %ld, PROT_READ)\n", i->data, 247 (long) i->size); 248 mprotect (i->data, i->size, PROT_READ); 249 } 250#endif 251 windowp->data = i->data; 252 windowp->size = i->size; 253 return TRUE; 254} 255 256#endif /* USE_MMAP */ 257