499fe48de8
Drop portions that are unlit or redundant with llvm-libunwind: builtin.c, unwind.h, and unwind_arm_ehabi_stub.c. This code should now work with -fPIE binaries, should we choose to build any that way. When backtrace() array is full, signal an error so the underlying Itanium-style C++ exception handling library (llvm-libunwind) knows to stop tracing instead of continuing. (It should stop on its own when it finishes unwinding, so this is mostly an extra seatbelt against an infinite loop bug in the unwinder.)
75 lines
2.3 KiB
C
75 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 && 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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