44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
/*
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* SignalSafeUnwind.h
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef FLOW_SIGNAL_SAFE_UNWIND
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#define FLOW_SIGNAL_SAFE_UNWIND
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#pragma once
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#include "flow/Platform.h"
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// backtrace() and exception unwinding in glibc both call dl_iterate_phdr(),
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// which takes the loader lock and so is not async signal safe. Profiling or slow task
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// profiling can deadlock when they interrupt the unwinding of an exception.
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// This library overrides the implementation of dl_iterate_phdr() so that it
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// can be async signal safe in this context, at the cost of other restrictions
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// Call this function after all dynamic libraries are loaded
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// (no further calls to dlopen() or dlclose() are permitted).
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// After calling it, dl_iterate_phdr() will be async-signal-safe.
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// At this time, it is a no-op on all platforms except Linux
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void initSignalSafeUnwind();
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// This can be used by tests to measure the number of calls to dl_iterate_phdr intercepted
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extern int64_t dl_iterate_phdr_calls;
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#endif |