| /* mmapio.c -- File views using mmap. |
| Copyright (C) 2012-2018 Free Software Foundation, Inc. |
| Written by Ian Lance Taylor, Google. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| |
| (1) Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| |
| (2) Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in |
| the documentation and/or other materials provided with the |
| distribution. |
| |
| (3) The name of the author may not be used to |
| endorse or promote products derived from this software without |
| specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, |
| INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| POSSIBILITY OF SUCH DAMAGE. */ |
| |
| #include "config.h" |
| |
| #include <errno.h> |
| #include <sys/types.h> |
| #include <sys/mman.h> |
| #include <unistd.h> |
| |
| #include "backtrace.h" |
| #include "internal.h" |
| |
| #ifndef MAP_FAILED |
| #define MAP_FAILED ((void *)-1) |
| #endif |
| |
| /* This file implements file views and memory allocation when mmap is |
| available. */ |
| |
| /* Create a view of SIZE bytes from DESCRIPTOR at OFFSET. */ |
| |
| int |
| backtrace_get_view (struct backtrace_state *state ATTRIBUTE_UNUSED, |
| int descriptor, off_t offset, size_t size, |
| backtrace_error_callback error_callback, |
| void *data, struct backtrace_view *view) |
| { |
| size_t pagesize; |
| unsigned int inpage; |
| off_t pageoff; |
| void *map; |
| |
| pagesize = getpagesize (); |
| inpage = offset % pagesize; |
| pageoff = offset - inpage; |
| |
| size += inpage; |
| size = (size + (pagesize - 1)) & ~ (pagesize - 1); |
| |
| map = mmap (NULL, size, PROT_READ, MAP_PRIVATE, descriptor, pageoff); |
| if (map == MAP_FAILED) |
| { |
| error_callback (data, "mmap", errno); |
| return 0; |
| } |
| |
| view->data = (char *) map + inpage; |
| view->base = map; |
| view->len = size; |
| |
| return 1; |
| } |
| |
| /* Release a view read by backtrace_get_view. */ |
| |
| void |
| backtrace_release_view (struct backtrace_state *state ATTRIBUTE_UNUSED, |
| struct backtrace_view *view, |
| backtrace_error_callback error_callback, |
| void *data) |
| { |
| union { |
| const void *cv; |
| void *v; |
| } const_cast; |
| |
| const_cast.cv = view->base; |
| if (munmap (const_cast.v, view->len) < 0) |
| error_callback (data, "munmap", errno); |
| } |