From d6eaea10e438026bdc72a9b1ead7cc3b0bc58621 Mon Sep 17 00:00:00 2001
From: Nicholas McDaniel <nickmcdaniel00@gmail.com>
Date: Sat, 29 Nov 2025 18:41:45 -0500
Subject: [PATCH 1/2] Ensure the dfhack signal handler doesn't appear in
 crashlogs

---
 library/Crashlog.cpp | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/library/Crashlog.cpp b/library/Crashlog.cpp
index c560666f99..681e4fd4c5 100644
--- a/library/Crashlog.cpp
+++ b/library/Crashlog.cpp
@@ -1,4 +1,5 @@
 #include "DFHackVersion.h"
+
 #include <csignal>
 #include <iomanip>
 #include <filesystem>
@@ -42,7 +43,8 @@ void signal_crashlog_complete() {
 
 std::thread crashlog_thread;
 
-extern "C" void dfhack_crashlog_handle_signal(int sig) {
+// Force this method to be inlined so that it doesn't create a stack frame
+[[gnu::always_inline]] inline void handle_signal_internal(int sig) {
     if (shutdown.load() || crashed.exchange(true) || crashlog_ready.load()) {
         // Ensure the signal handler doesn't try to write a crashlog
         // whilst the crashlog thread is unavailable.
@@ -61,8 +63,12 @@ extern "C" void dfhack_crashlog_handle_signal(int sig) {
     std::quick_exit(1);
 }
 
+extern "C" void dfhack_crashlog_handle_signal(int sig) {
+    handle_signal_internal(sig);
+}
+
 void dfhack_crashlog_handle_terminate() {
-    dfhack_crashlog_handle_signal(0);
+    handle_signal_internal(0);
 }
 
 std::string signal_name(int sig) {
@@ -122,8 +128,9 @@ void dfhack_save_crashlog() {
             crashlog << "Signal " << signal << "\n";
         }
 
-        for (int i = 0; i < crash_info.backtrace_entries; i++) {
-            crashlog << i << "> " << backtrace_strings[i] << "\n";
+        // Skip the first backtrace entry as it will always be dfhack_crashlog_handle_(signal|terminate)
+        for (int i = 1; i < crash_info.backtrace_entries; i++) {
+            crashlog << i - 1 << "> " << backtrace_strings[i] << "\n";
         }
     } catch (...) {}
 

From 5687f5c0f0ee465d31a6a9b82e1920919b911422 Mon Sep 17 00:00:00 2001
From: Nicholas McDaniel <nickmcdaniel00@gmail.com>
Date: Thu, 4 Dec 2025 15:01:47 -0500
Subject: [PATCH 2/2] Make a failure to obtain relevant crash backtrace obvious

---
 library/Crashlog.cpp | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/library/Crashlog.cpp b/library/Crashlog.cpp
index 681e4fd4c5..3860e0106e 100644
--- a/library/Crashlog.cpp
+++ b/library/Crashlog.cpp
@@ -111,10 +111,6 @@ std::filesystem::path get_crashlog_path() {
 
 void dfhack_save_crashlog() {
     char** backtrace_strings = backtrace_symbols(crash_info.backtrace, crash_info.backtrace_entries);
-    if (!backtrace_strings) {
-        // Allocation failed, give up
-        return;
-    }
     try {
         std::filesystem::path crashlog_path = get_crashlog_path();
         std::ofstream crashlog(crashlog_path);
@@ -128,9 +124,14 @@ void dfhack_save_crashlog() {
             crashlog << "Signal " << signal << "\n";
         }
 
-        // Skip the first backtrace entry as it will always be dfhack_crashlog_handle_(signal|terminate)
-        for (int i = 1; i < crash_info.backtrace_entries; i++) {
-            crashlog << i - 1 << "> " << backtrace_strings[i] << "\n";
+        if (crash_info.backtrace_entries >= 2 && backtrace_strings != nullptr) {
+            // Skip the first backtrace entry as it will always be dfhack_crashlog_handle_(signal|terminate)
+            for (int i = 1; i < crash_info.backtrace_entries; i++) {
+                crashlog << i - 1 << "> " << backtrace_strings[i] << "\n";
+            }
+        } else {
+            // Make it clear if no relevant backtrace was able to be obtained
+            crashlog << "Failed to obtain relevant backtrace\n";
         }
     } catch (...) {}