117 lines
5.3 KiB
C++
117 lines
5.3 KiB
C++
// Copyright 2018 The Abseil 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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// https://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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// -----------------------------------------------------------------------------
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// File: failure_signal_handler.h
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// -----------------------------------------------------------------------------
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//
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// This file configures the Abseil *failure signal handler* to capture and dump
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// useful debugging information (such as a stacktrace) upon program failure.
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//
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// To use the failure signal handler, call `absl::InstallFailureSignalHandler()`
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// very early in your program, usually in the first few lines of main():
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//
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// int main(int argc, char** argv) {
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// // Initialize the symbolizer to get a human-readable stack trace
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// absl::InitializeSymbolizer(argv[0]);
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//
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// absl::FailureSignalHandlerOptions options;
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// absl::InstallFailureSignalHandler(options);
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// DoSomethingInteresting();
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// return 0;
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// }
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//
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// Any program that raises a fatal signal (such as `SIGSEGV`, `SIGILL`,
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// `SIGFPE`, `SIGABRT`, `SIGTERM`, `SIGBUG`, and `SIGTRAP`) will call the
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// installed failure signal handler and provide debugging information to stderr.
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//
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// Note that you should *not* install the Abseil failure signal handler more
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// than once. You may, of course, have another (non-Abseil) failure signal
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// handler installed (which would be triggered if Abseil's failure signal
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// handler sets `call_previous_handler` to `true`).
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#ifndef ABSL_DEBUGGING_FAILURE_SIGNAL_HANDLER_H_
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#define ABSL_DEBUGGING_FAILURE_SIGNAL_HANDLER_H_
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namespace absl {
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// FailureSignalHandlerOptions
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//
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// Struct for holding `absl::InstallFailureSignalHandler()` configuration
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// options.
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struct FailureSignalHandlerOptions {
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// If true, try to symbolize the stacktrace emitted on failure, provided that
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// you have initialized a symbolizer for that purpose. (See symbolize.h for
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// more information.)
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bool symbolize_stacktrace = true;
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// If true, try to run signal handlers on an alternate stack (if supported on
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// the given platform). An alternate stack is useful for program crashes due
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// to a stack overflow; by running on a alternate stack, the signal handler
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// may run even when normal stack space has been exausted. The downside of
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// using an alternate stack is that extra memory for the alternate stack needs
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// to be pre-allocated.
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bool use_alternate_stack = true;
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// If positive, indicates the number of seconds after which the failure signal
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// handler is invoked to abort the program. Setting such an alarm is useful in
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// cases where the failure signal handler itself may become hung or
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// deadlocked.
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int alarm_on_failure_secs = 3;
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// If true, call the previously registered signal handler for the signal that
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// was received (if one was registered) after the existing signal handler
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// runs. This mechanism can be used to chain signal handlers together.
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//
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// If false, the signal is raised to the default handler for that signal
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// (which normally terminates the program).
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//
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// IMPORTANT: If true, the chained fatal signal handlers must not try to
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// recover from the fatal signal. Instead, they should terminate the program
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// via some mechanism, like raising the default handler for the signal, or by
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// calling `_exit()`. Note that the failure signal handler may put parts of
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// the Abseil library into a state from which they cannot recover.
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bool call_previous_handler = false;
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// If non-null, indicates a pointer to a callback function that will be called
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// upon failure, with a std::string argument containing failure data. This function
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// may be used as a hook to write failure data to a secondary location, such
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// as a log file. This function may also be called with null data, as a hint
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// to flush any buffered data before the program may be terminated. Consider
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// flushing any buffered data in all calls to this function.
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//
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// Since this function runs within a signal handler, it should be
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// async-signal-safe if possible.
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// See http://man7.org/linux/man-pages/man7/signal-safety.7.html
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void (*writerfn)(const char*) = nullptr;
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};
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// InstallFailureSignalHandler()
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//
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// Installs a signal handler for the common failure signals `SIGSEGV`, `SIGILL`,
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// `SIGFPE`, `SIGABRT`, `SIGTERM`, `SIGBUG`, and `SIGTRAP` (provided they exist
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// on the given platform). The failure signal handler dumps program failure data
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// useful for debugging in an unspecified format to stderr. This data may
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// include the program counter, a stacktrace, and register information on some
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// systems; do not rely on an exact format for the output, as it is subject to
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// change.
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void InstallFailureSignalHandler(const FailureSignalHandlerOptions& options);
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namespace debugging_internal {
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const char* FailureSignalToString(int signo);
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} // namespace debugging_internal
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} // namespace absl
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#endif // ABSL_DEBUGGING_FAILURE_SIGNAL_HANDLER_H_
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