crash: add a minimal handler for coredumping signals

CMakeLists.txt

@@ -124,6 +124,7 @@ if (NOT WIN32)
         memory/system.cpp
         memory/system.hpp
         debug_posix.cpp
+        debug/crash_posix.cpp
         io_posix.cpp
         io_posix.hpp
         library_posix.hpp
@@ -145,6 +146,7 @@ if (WIN32)
     list (
         APPEND UTIL_FILES
         debug_win32.cpp
+        debug/crash_win32.cpp
         exe_win32.cpp
         io_win32.cpp
         io_win32.hpp
@@ -303,6 +305,7 @@ list (
     debug/assert.hpp
     debug/compiler.cpp
     debug/compiler.hpp
+    debug/crash.hpp
     debug/debugger.cpp
     debug/debugger.hpp
     debug/memory.cpp

debug/crash.hpp

@@ -0,0 +1,13 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#pragma once
+
+namespace cruft::debug {
+    void init_crash_handler (void);
+}

debug/crash_posix.cpp

@@ -0,0 +1,68 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "crash.hpp"
+
+#include "../backtrace.hpp"
+#include "../posix/except.hpp"
+#include "../map/fixed.hpp"
+
+#include <signal.h>
+#include <cstring>
+
+
+///////////////////////////////////////////////////////////////////////////////
+static constexpr
+int to_handle[] = {
+    SIGBUS,
+    SIGFPE,
+    SIGILL,
+    SIGSEGV,
+    SIGABRT,
+};
+
+
+auto constexpr handled_count = std::size (to_handle);
+
+
+cruft::map::fixed<handled_count, int, struct sigaction> s_old_handlers;
+
+
+//-----------------------------------------------------------------------------
+void dumping_handler (int sig, siginfo_t *info, void *ucontext)
+{
+    std::clog << cruft::backtrace () << '\n';
+
+    // Forward the signal to the previously registered handler
+    auto const next_handler = s_old_handlers.at (sig);
+    if (next_handler.sa_flags & SA_SIGINFO)
+        next_handler.sa_sigaction (sig, info, ucontext);
+    else
+        next_handler.sa_handler (sig);
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+cruft::debug::init_crash_handler ()
+{
+    struct sigaction new_handler {};
+    memset (&new_handler, 0, sizeof (new_handler));
+    new_handler.sa_flags = SA_SIGINFO;
+    new_handler.sa_sigaction = dumping_handler;
+
+    for (auto const sigid: to_handle) {
+        cruft::posix::error::try_code (
+            sigaction (
+                sigid,
+                &new_handler,
+                &s_old_handlers[sigid]
+            )
+        );
+    }
+}

debug/crash_win32.cpp

@@ -0,0 +1,8 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2019, Danny Robson <danny@nerdcruft.net>
+ */
+