From 323dae6c7fd982f444e1736410888037239e662c Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Sat, 2 Sep 2017 13:41:26 -0600
Subject: Install a crash handler

..that prints a backtrace on crash.
---
 applications/kube/CMakeLists.txt |   1 +
 applications/kube/main.cpp       | 106 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 107 insertions(+)

diff --git a/applications/kube/CMakeLists.txt b/applications/kube/CMakeLists.txt
index 2d0df2ad..2d4c9da7 100644
--- a/applications/kube/CMakeLists.txt
+++ b/applications/kube/CMakeLists.txt
@@ -21,6 +21,7 @@ target_link_libraries(${PROJECT_NAME}
     Qt5::Widgets
     Qt5::WebEngine
     KF5::Package
+    ${CMAKE_DL_LIBS}
 )
 
 install(TARGETS ${PROJECT_NAME} DESTINATION ${KDE_INSTALL_TARGETS_DEFAULT_ARGS})
diff --git a/applications/kube/main.cpp b/applications/kube/main.cpp
index 44897b2e..a6b51c38 100644
--- a/applications/kube/main.cpp
+++ b/applications/kube/main.cpp
@@ -17,6 +17,19 @@
     02110-1301, USA.
 */
 
+#include <signal.h>
+#include <execinfo.h>
+#include <csignal>
+#include <iostream>
+#include <cstdlib>
+#include <cxxabi.h>
+#include <dlfcn.h>
+#include <ostream>
+#include <sstream>
+#include <thread>
+#include <chrono>
+#include <unistd.h>
+
 #include <QApplication>
 #include <QQmlApplicationEngine>
 
@@ -28,6 +41,94 @@
 
 #include <QDebug>
 
+//Print a demangled stacktrace
+void printStacktrace()
+{
+    int skip = 1;
+    void *callstack[128];
+    const int nMaxFrames = sizeof(callstack) / sizeof(callstack[0]);
+    char buf[1024];
+    int nFrames = backtrace(callstack, nMaxFrames);
+    char **symbols = backtrace_symbols(callstack, nFrames);
+
+    std::ostringstream trace_buf;
+    for (int i = skip; i < nFrames; i++) {
+        // printf("%s\n", symbols[i]);
+        Dl_info info;
+        if (dladdr(callstack[i], &info) && info.dli_sname) {
+            char *demangled = NULL;
+            int status = -1;
+            if (info.dli_sname[0] == '_') {
+                demangled = abi::__cxa_demangle(info.dli_sname, NULL, 0, &status);
+            }
+            snprintf(buf, sizeof(buf), "%-3d %*p %s + %zd\n",
+                    i, int(2 + sizeof(void*) * 2), callstack[i],
+                    status == 0 ? demangled :
+                    info.dli_sname == 0 ? symbols[i] : info.dli_sname,
+                    (char *)callstack[i] - (char *)info.dli_saddr);
+            free(demangled);
+        } else {
+            snprintf(buf, sizeof(buf), "%-3d %*p %s\n",
+                    i, int(2 + sizeof(void*) * 2), callstack[i], symbols[i]);
+        }
+        trace_buf << buf;
+    }
+    free(symbols);
+    if (nFrames == nMaxFrames) {
+        trace_buf << "[truncated]\n";
+    }
+    std::cerr << trace_buf.str();
+}
+
+static int sCounter = 0;
+
+void crashHandler(int signal)
+{
+    //Guard against crashing in here
+    if (sCounter > 1) {
+        std::_Exit(EXIT_FAILURE);
+    }
+    sCounter++;
+
+    if (signal == SIGABRT) {
+        std::cerr << "SIGABRT received\n";
+    } else if (signal == SIGSEGV) {
+        std::cerr << "SIGSEV received\n";
+    } else {
+        std::cerr << "Unexpected signal " << signal << " received\n";
+    }
+
+    printStacktrace();
+
+    std::fprintf(stdout, "Sleeping for 10s to attach a debugger: gdb attach %i\n", getpid());
+    std::this_thread::sleep_for(std::chrono::seconds(10));
+
+    // std::system("exec gdb -p \"$PPID\" -ex \"thread apply all bt\"");
+    // This only works if we actually have xterm and X11 available
+    // std::system("exec xterm -e gdb -p \"$PPID\"");
+
+    std::_Exit(EXIT_FAILURE);
+}
+
+void terminateHandler()
+{
+    // std::exception_ptr exptr = std::current_exception();
+    // if (exptr != 0)
+    // {
+    //     // the only useful feature of std::exception_ptr is that it can be rethrown...
+    //     try {
+    //         std::rethrow_exception(exptr);
+    //     } catch (std::exception &ex) {
+    //         std::fprintf(stderr, "Terminated due to exception: %s\n", ex.what());
+    //     } catch (...) {
+    //         std::fprintf(stderr, "Terminated due to unknown exception\n");
+    //     }
+    // } else {
+        std::fprintf(stderr, "Terminated due to unknown reason.\n");
+    // }
+    std::abort();
+}
+
 class KubeImageProvider : public QQuickImageProvider
 {
 public:
@@ -68,6 +169,11 @@ public:
 
 int main(int argc, char *argv[])
 {
+
+    std::signal(SIGSEGV, crashHandler);
+    std::signal(SIGABRT, crashHandler);
+    std::set_terminate(terminateHandler);
+
     QApplication app(argc, argv);
     app.setFont(QFont{"Noto Sans", app.font().pointSize(), QFont::Normal});
 
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