From 8722daa6e790241f1f7adab316a5ae908f28ce93 Mon Sep 17 00:00:00 2001
From: Sadie Powell <sadie@witchery.services>
Date: Fri, 16 May 2025 15:15:30 +0100
Subject: [PATCH] Only allow one instance of Anope at once.

---
 src/init.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/init.cpp b/src/init.cpp
index 75e6a2419..89a946a98 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -235,6 +235,18 @@ static void write_pidfile()
 	if (Anope::NoPID || pidfile.empty())
 		return;
 
+#ifndef _WIN32
+	std::ifstream oldstream(pidfile.str());
+	if (oldstream.is_open())
+	{
+		pid_t oldpid = 0;
+		oldstream >> oldpid;
+		if (oldpid && kill(oldpid, 0) == 0)
+			throw CoreException("Anope is already running with process id " + Anope::ToString(oldpid));
+	}
+	oldstream.close();
+#endif
+
 	std::ofstream stream(pidfile.str());
 	if (!stream.is_open())
 		throw CoreException("Can not write to PID file " + pidfile);