--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/crashcatcher.cpp Fri Oct 18 21:52:09 2013 +0300
@@ -0,0 +1,113 @@
+#ifdef __unix__
+
+#include <QString>
+#include <QProcess>
+#include <QTemporaryFile>
+#include <QMessageBox>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include "crashcatcher.h"
+#include "types.h"
+#include "dialogs.h"
+
+// Is the crash catcher active now?
+static bool g_crashCatcherActive = false;
+
+// If an assertion failed, what was it?
+static str g_assertionFailure;
+
+// List of signals to catch and crash on
+static QList<int> g_signalsToCatch ({
+ SIGSEGV, // segmentation fault
+ SIGABRT, // abort() calls
+ SIGFPE, // floating point exceptions (e.g. division by zero)
+ SIGILL, // illegal instructions
+});
+
+// =============================================================================
+// -----------------------------------------------------------------------------
+static void handleSignal (int sig)
+{ printf ("caught signal %d\n", sig);
+
+ if (g_crashCatcherActive)
+ { printf ("caught signal while crash catcher is active!\n");
+ return;
+ }
+
+ if (g_signalsToCatch.indexOf (sig) != -1)
+ { const pid_t pid = getpid();
+ QProcess proc;
+ QTemporaryFile commandsFile;
+
+ g_crashCatcherActive = true;
+ printf ("%s: crashed with signal %d, launching gdb\n", __func__, sig);
+
+ if (commandsFile.open())
+ { commandsFile.write (fmt ("attach %1\n", pid).toLocal8Bit());
+ commandsFile.write (str ("backtrace full\n").toLocal8Bit());
+ commandsFile.write (str ("detach\n").toLocal8Bit());
+ commandsFile.write (str ("quit").toLocal8Bit());
+ commandsFile.flush();
+ commandsFile.close();
+ }
+
+ QStringList args ({"-x", commandsFile.fileName()});
+
+ proc.start ("gdb", args);
+
+ // Linux doesn't allow ptrace to be used on anything but direct child processes
+ // so we need to use prctl to register an exception to this to allow GDB attach to us.
+ // We need to do this now and no earlier because only now we actually know GDB's PID.
+ prctl (PR_SET_PTRACER, proc.pid(), 0, 0, 0);
+
+ proc.waitForFinished (5000);
+ str output = QString (proc.readAllStandardOutput());
+ str err = QString (proc.readAllStandardError());
+
+ bombBox (fmt ("<h3>Program crashed with signal %1</h3>\n\n"
+ "%2"
+ "<p><b>GDB <tt>stdout</tt>:</b></p><pre>%3</pre>\n"
+ "<p><b>GDB <tt>stderr</tt>:</b></p><pre>%4</pre>",
+ sig, (!g_assertionFailure.isEmpty()) ? g_assertionFailure : "", output, err));
+ exit (137);
+ }
+}
+
+// =============================================================================
+// -----------------------------------------------------------------------------
+void initCrashCatcher()
+{ struct sigaction sighandler;
+ sighandler.sa_handler = &handleSignal;
+ sighandler.sa_flags = 0;
+ sigemptyset (&sighandler.sa_mask);
+
+ for (int sig : g_signalsToCatch)
+ sigaction (sig, &sighandler, null);
+
+ log ("%1: crash catcher hooked to signals: %2\n", __func__, g_signalsToCatch);
+}
+#endif // #ifdef __unix__
+
+// =============================================================================
+// This function must be readily available in both Windows and Linux. We display
+// the bomb box straight in Windows while in Linux we let abort() trigger the
+// signal handler, which will cause the usual bomb box with GDB diagnostics.
+// Said prompt will embed the assertion failure information.
+// -----------------------------------------------------------------------------
+void assertionFailure (const char* file, int line, const char* funcname, const char* expr)
+{ str errmsg = fmt (
+ "<p><b>File</b>: <tt>%1</tt><br />"
+ "<b>Line</b>: <tt>%2</tt><br />"
+ "<b>Function:</b> <tt>%3</tt></p>"
+ "<p>Assertion <b><tt>`%4'</tt></b> failed.</p>",
+ file, line, funcname, expr);
+
+ g_assertionFailure = errmsg;
+
+#ifndef __unix__
+ bombBox (errmsg);
+#endif
+
+ abort();
+}
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