Merge pull request #12713 from NixOS/mergify/bp/2.27-maintenance/pr-12636

port crash-handler from lix to nix (backport #12636)

src/nix/crash-handler.cc

@@ -0,0 +1,67 @@
+#include "crash-handler.hh"
+#include "fmt.hh"
+#include "logging.hh"
+
+#include <boost/core/demangle.hpp>
+#include <exception>
+#include <sstream>
+
+// Darwin and FreeBSD stdenv do not define _GNU_SOURCE but do have _Unwind_Backtrace.
+#if __APPLE__ || __FreeBSD__
+#  define BOOST_STACKTRACE_GNU_SOURCE_NOT_REQUIRED
+#endif
+
+#include <boost/stacktrace/stacktrace.hpp>
+
+#ifndef _WIN32
+#  include <syslog.h>
+#endif
+
+namespace nix {
+
+namespace {
+
+void logFatal(std::string const & s)
+{
+    writeToStderr(s + "\n");
+    // std::string for guaranteed null termination
+#ifndef _WIN32
+    syslog(LOG_CRIT, "%s", s.c_str());
+#endif
+}
+
+void onTerminate()
+{
+    logFatal(
+        "Nix crashed. This is a bug. Please report this at https://github.com/NixOS/nix/issues with the following information included:\n");
+    try {
+        std::exception_ptr eptr = std::current_exception();
+        if (eptr) {
+            std::rethrow_exception(eptr);
+        } else {
+            logFatal("std::terminate() called without exception");
+        }
+    } catch (const std::exception & ex) {
+        logFatal(fmt("Exception: %s: %s", boost::core::demangle(typeid(ex).name()), ex.what()));
+    } catch (...) {
+        logFatal("Unknown exception!");
+    }
+
+    logFatal("Stack trace:");
+    std::stringstream ss;
+    ss << boost::stacktrace::stacktrace();
+    logFatal(ss.str());
+
+    std::abort();
+}
+}
+
+void registerCrashHandler()
+{
+    // DO NOT use this for signals. Boost stacktrace is very much not
+    // async-signal-safe, and in a world with ASLR, addr2line is pointless.
+    //
+    // If you want signals, set up a minidump system and do it out-of-process.
+    std::set_terminate(onTerminate);
+}
+}

src/nix/crash-handler.hh

@@ -0,0 +1,11 @@
+#pragma once
+/// @file Crash handler for Nix that prints back traces (hopefully in instances where it is not just going to crash the
+/// process itself).
+
+namespace nix {
+
+/** Registers the Nix crash handler for std::terminate (currently; will support more crashes later). See also
+ * detectStackOverflow().  */
+void registerCrashHandler();
+
+}

src/nix/main.cc

@@ -20,6 +20,7 @@
 #include "flake/flake.hh"
 #include "self-exe.hh"
 #include "json-utils.hh"
+#include "crash-handler.hh"
 
 #include <sys/types.h>
 #include <regex>
@@ -354,6 +355,8 @@ void mainWrapped(int argc, char * * argv)
 {
     savedArgv = argv;
 
+    registerCrashHandler();
+
     /* The chroot helper needs to be run before any threads have been
        started. */
 #ifndef _WIN32

src/nix/meson.build

@@ -77,6 +77,7 @@ nix_sources = [config_h] + files(
   'config-check.cc',
   'config.cc',
   'copy.cc',
+  'crash-handler.cc',
   'derivation-add.cc',
   'derivation-show.cc',
   'derivation.cc',