101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/* mmapio.c -- File views using mmap.
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Copyright (C) 2012-2017 Free Software Foundation, Inc.
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Written by Ian Lance Taylor, Google.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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(1) Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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(2) Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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(3) The name of the author may not be used to
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endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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#include "config.h"
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include "backtrace.h"
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#include "internal.h"
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#ifndef MAP_FAILED
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#define MAP_FAILED ((void *)-1)
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#endif
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/* This file implements file views and memory allocation when mmap is
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available. */
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/* Create a view of SIZE bytes from DESCRIPTOR at OFFSET. */
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int
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backtrace_get_view (struct backtrace_state *state ATTRIBUTE_UNUSED,
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int descriptor, off_t offset, size_t size,
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backtrace_error_callback error_callback,
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void *data, struct backtrace_view *view)
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{
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size_t pagesize;
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unsigned int inpage;
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off_t pageoff;
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void *map;
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pagesize = getpagesize ();
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inpage = offset % pagesize;
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pageoff = offset - inpage;
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size += inpage;
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size = (size + (pagesize - 1)) & ~ (pagesize - 1);
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map = mmap (NULL, size, PROT_READ, MAP_PRIVATE, descriptor, pageoff);
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if (map == MAP_FAILED)
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{
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error_callback (data, "mmap", errno);
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return 0;
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}
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view->data = (char *) map + inpage;
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view->base = map;
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view->len = size;
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return 1;
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}
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/* Release a view read by backtrace_get_view. */
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void
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backtrace_release_view (struct backtrace_state *state ATTRIBUTE_UNUSED,
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struct backtrace_view *view,
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backtrace_error_callback error_callback,
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void *data)
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{
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union {
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const void *cv;
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void *v;
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} const_cast;
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const_cast.cv = view->base;
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if (munmap (const_cast.v, view->len) < 0)
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error_callback (data, "munmap", errno);
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}
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