| /* Support for memory-mapped windows into a BFD. |
| Copyright (C) 1995-2016 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 3 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., 51 Franklin Street - Fifth Floor, Boston, |
| MA 02110-1301, USA. */ |
| |
| #include "sysdep.h" |
| |
| #include "bfd.h" |
| #include "libbfd.h" |
| |
| /* Currently, if USE_MMAP is undefined, none of the window stuff is |
| used. Enabled by --with-mmap. */ |
| |
| #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, (unsigned long) 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 == NULL) |
| { |
| i = bfd_zmalloc (sizeof (bfd_window_internal)); |
| if (i == NULL) |
| return FALSE; |
| i->data = NULL; |
| } |
| #ifdef HAVE_MMAP |
| if (ok_to_map |
| && (i->data == NULL || i->mapped == 1) |
| && (abfd->flags & BFD_IN_MEMORY) == 0) |
| { |
| file_ptr file_offset, offset2; |
| size_t real_size; |
| int fd; |
| |
| /* Find the real file and the real offset into it. */ |
| while (abfd->my_archive != NULL |
| && !bfd_is_thin_archive (abfd->my_archive)) |
| { |
| offset += abfd->origin; |
| abfd = abfd->my_archive; |
| } |
| |
| /* Seek into the file, to ensure it is open if cacheable. */ |
| if (abfd->iostream == NULL |
| && (abfd->iovec == NULL |
| || abfd->iovec->bseek (abfd, offset, SEEK_SET) != 0)) |
| goto free_and_fail; |
| |
| fd = fileno ((FILE *) abfd->iostream); |
| /* 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 != NULL && i->size < size) |
| { |
| munmap (i->data, i->size); |
| i->data = NULL; |
| } |
| 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); |
| windowp->data = 0; |
| if (debug_windows) |
| fprintf (stderr, "\t\tmmap failed!\n"); |
| goto free_and_fail; |
| } |
| 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; |
| i->refcount = 1; |
| windowp->i = i; |
| 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_or_free (i->data, size_to_alloc); |
| if (debug_windows) |
| fprintf (stderr, "\t-> %p\n", i->data); |
| if (i->data == NULL) |
| { |
| if (size_to_alloc == 0) |
| { |
| windowp->i = i; |
| return TRUE; |
| } |
| goto free_and_fail; |
| } |
| i->refcount = 1; |
| if (bfd_seek (abfd, offset, SEEK_SET) != 0) |
| goto free_and_fail; |
| i->size = bfd_bread (i->data, size, abfd); |
| if (i->size != size) |
| goto free_and_fail; |
| 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; |
| windowp->i = i; |
| return TRUE; |
| |
| free_and_fail: |
| /* We have a bfd_window_internal, but an error occurred. Free it. */ |
| free (i); |
| return FALSE; |
| } |
| |
| #endif /* USE_MMAP */ |