/* 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; . 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); 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 */