- 81cdce434ff1bd8fa54c832a11dda59af46e79cc Adds a failure signal handler to Abseil. by Derek Mauro <dmauro@google.com>

  - 40a973dd1b159e7455dd5fc06ac2d3f494d72c3e Remove test fixture requirement for ExceptionSafetyTester... by Abseil Team <absl-team@google.com>

GitOrigin-RevId: 81cdce434ff1bd8fa54c832a11dda59af46e79cc
Change-Id: Ia9fca98e38f229b68f7ec45600dee1bbd5dcff33

1 files changed, 103 insertions, 0 deletions

diff --git a/absl/debugging/failure_signal_handler.h b/absl/debugging/failure_signal_handler.h
new file mode 100644
index 000000000000..17522f00b13f
--- /dev/null
+++ b/absl/debugging/failure_signal_handler.h
@@ -0,0 +1,103 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+// This module allows the programmer to install a signal handler that
+// dumps useful debugging information (like a stacktrace) on program
+// failure. To use this functionality, call
+// absl::InstallFailureSignalHandler() very early in your program,
+// usually in the first few lines of main():
+//
+// int main(int argc, char** argv) {
+//   absl::InitializeSymbolizer(argv[0]);
+//   absl::FailureSignalHandlerOptions options;
+//   absl::InstallFailureSignalHandler(options);
+//   DoSomethingInteresting();
+//   return 0;
+// }
+
+#ifndef ABSL_DEBUGGING_FAILURE_SIGNAL_HANDLER_H_
+#define ABSL_DEBUGGING_FAILURE_SIGNAL_HANDLER_H_
+
+namespace absl {
+
+// Options struct for absl::InstallFailureSignalHandler().
+struct FailureSignalHandlerOptions {
+  // If true, try to symbolize the stacktrace emitted on failure.
+  bool symbolize_stacktrace = true;
+
+  // If true, try to run signal handlers on an alternate stack (if
+  // supported on the given platform). This is useful in the case
+  // where the program crashes due to a stack overflow. By running on
+  // a alternate stack, the signal handler might be able to run even
+  // when the normal stack space has been exausted. The downside of
+  // using an alternate stack is that extra memory for the alternate
+  // stack needs to be pre-allocated.
+  bool use_alternate_stack = true;
+
+  // If positive, FailureSignalHandler() sets an alarm to be delivered
+  // to the program after this many seconds, which will immediately
+  // abort the program. This is useful in the potential case where
+  // FailureSignalHandler() itself is hung or deadlocked.
+  int alarm_on_failure_secs = 3;
+
+  // If false, after absl::FailureSignalHandler() runs, the signal is
+  // raised to the default handler for that signal (which normally
+  // terminates the program).
+  //
+  // If true, after absl::FailureSignalHandler() runs, it will call
+  // the previously registered signal handler for the signal that was
+  // received (if one was registered). This can be used to chain
+  // signal handlers.
+  //
+  // IMPORTANT: If true, the chained fatal signal handlers must not
+  // try to recover from the fatal signal. Instead, they should
+  // terminate the program via some mechanism, like raising the
+  // default handler for the signal, or by calling _exit().
+  // absl::FailureSignalHandler() may put parts of the Abseil
+  // library into a state that cannot be recovered from.
+  bool call_previous_handler = false;
+
+  // If not null, this function may be called with a std::string argument
+  // containing failure data. This function is used as a hook to write
+  // the failure data to a secondary location, for instance, to a log
+  // file. This function may also be called with a null data
+  // argument. This is a hint that this is a good time to flush any
+  // buffered data before the program may be terminated. Consider
+  // flushing any buffered data in all calls to this function.
+  //
+  // Since this function runs in a signal handler, it should be
+  // async-signal-safe if possible.
+  // See http://man7.org/linux/man-pages/man7/signal-safety.7.html
+  void (*writerfn)(const char*) = nullptr;
+};
+
+// Installs a signal handler for the common failure signals SIGSEGV,
+// SIGILL, SIGFPE, SIGABRT, SIGTERM, SIGBUG, and SIGTRAP (if they
+// exist on the given platform). The signal handler dumps program
+// failure data in a unspecified format to stderr. The data dumped by
+// the signal handler includes information that may be useful in
+// debugging the failure. This may include the program counter, a
+// stacktrace, and register information on some systems.  Do not rely
+// on the exact format of the output; it is subject to change.
+void InstallFailureSignalHandler(const FailureSignalHandlerOptions& options);
+
+namespace debugging_internal {
+const char* FailureSignalToString(int signo);
+}  // namespace debugging_internal
+
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_FAILURE_SIGNAL_HANDLER_H_