895a7e604d
If Unwind_Backtrace is broken, ctx.n will still contain ~0, and we will
return that which poor behavior for the user, so return 0 instead.
We could document ~0 to be an error, but that would deviate from the
Linux behavior which is not desirable. Noted by Poul-Henning Kamp
PR: 209842
77 lines
2.3 KiB
C
77 lines
2.3 KiB
C
/* $NetBSD: unwind.c,v 1.3 2019/01/30 22:46:49 mrg Exp $ */
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/*-
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* Copyright (c) 2012 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Christos Zoulas.
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*
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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
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* are 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 the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING 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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*/
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#include <stdio.h>
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#include "unwind.h"
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#include "execinfo.h"
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struct tracer_context {
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void **arr;
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size_t len;
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size_t n;
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};
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static _Unwind_Reason_Code
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tracer(struct _Unwind_Context *ctx, void *arg)
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{
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struct tracer_context *t = arg;
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if (t->n == (size_t)~0) {
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/* Skip backtrace frame */
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t->n = 0;
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return 0;
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}
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if (t->n < t->len)
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t->arr[t->n++] = (void *)_Unwind_GetIP(ctx);
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else
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return _URC_END_OF_STACK;
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return _URC_NO_REASON;
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}
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size_t
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backtrace(void **arr, size_t len)
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{
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struct tracer_context ctx;
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ctx.arr = arr;
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ctx.len = len;
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ctx.n = (size_t)~0;
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_Unwind_Backtrace(tracer, &ctx);
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if (ctx.n == (size_t)~0)
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ctx.n = 0;
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else if (ctx.n > 0)
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ctx.arr[--ctx.n] = NULL; /* Skip frame below __start */
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return ctx.n;
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}
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