binutils-gdb/libbacktrace/mmapio.c
Andrew Burgess 63a4b10683 Copy in libbacktrace from gcc
This copies in libbacktrace from the gcc repository as it was in the
commit 62e420293a293608f383d9b9c7f2debd666e9fc9.  GDB is going to
start using this library soon.

A dependency between GDB and libbacktrace has already been added to
the top level Makefile, so, after this commit, when building GDB,
libbacktrace will be built first.  However, libbacktrace is not yet
linked into GDB, or used by GDB in any way.

It is possible to stop libbacktrace being built by configuring the
tree with --disable-libbacktrace.

This commit does NOT update src-release.sh, that will be done in the
next commit, this commit ONLY imports libbacktrace from gcc.  This
means that if you try to make a release of GDB from exactly this
commit then the release tar file will not include libbacktrace.
However, as libbacktrace is an optional dependency this is fine.
2021-09-28 12:21:21 +01:00

111 lines
3.1 KiB
C

/* mmapio.c -- File views using mmap.
Copyright (C) 2012-2021 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 HAVE_DECL_GETPAGESIZE
extern int getpagesize (void);
#endif
#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, uint64_t size,
backtrace_error_callback error_callback,
void *data, struct backtrace_view *view)
{
size_t pagesize;
unsigned int inpage;
off_t pageoff;
void *map;
if ((uint64_t) (size_t) size != size)
{
error_callback (data, "file size too large", 0);
return 0;
}
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);
}