From 78d1c731e3181ee77af3dbabcec40b10e473702c Mon Sep 17 00:00:00 2001
From: mckaygerhard <mckaygerhard@gmail.com>
Date: Thu, 5 Jan 2023 16:41:15 -0400
Subject: [PATCH] Fix get_server_status() segfault due to uninitialized m_env

* Fixes [#7857](https://github.com/minetest/minetest/issues/7857)
  minetest.get_server_status() causes a Segmentation fault
  tacken from https://github.com/minetest/minetest/commit/81d55338fa26cf26d43e1e632b9a089a787230dd
* backported commit 13ad926546def65f01b5941ebb21493278189bea
---
 src/server.cpp | 51 ++++++++++++++++++++++++++------------------------
 1 file changed, 27 insertions(+), 24 deletions(-)

diff --git a/src/server.cpp b/src/server.cpp
index e1befcffc..0aaec809a 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -3013,36 +3013,39 @@ PlayerSAO* Server::getPlayerSAO(u16 peer_id)
 std::wstring Server::getStatusString()
 {
 	std::wostringstream os(std::ios_base::binary);
-	os<<L"# Server: ";
+	os << L"# Server: ";
 	// Version
-	os<<L"version="<<narrow_to_wide(g_version_string);
+	os << L"version=" << narrow_to_wide(g_version_string);
 	// Uptime
-	os<<L", uptime="<<m_uptime.get();
+	os < <L", uptime=" << m_uptime.get();
 	// Max lag estimate
-	os<<L", max_lag="<<m_env->getMaxLagEstimate();
+	os << L", max_lag=" << (m_env ? m_env->getMaxLagEstimate() : 0);
 	// Information about clients
 	bool first = true;
-	os<<L", clients={";
-	std::vector<u16> clients = m_clients.getClientIDs();
-	for (std::vector<u16>::iterator i = clients.begin(); i != clients.end(); ++i) {
-		// Get player
-		RemotePlayer *player = m_env->getPlayer(*i);
-		// Get name of player
-		std::wstring name = L"unknown";
-		if (player != NULL)
-			name = narrow_to_wide(player->getName());
-		// Add name to information string
-		if(!first)
-			os << L", ";
-		else
-			first = false;
-		os << name;
-	}
+	os << L", clients={";
+	if (m_env) {
+		std::vector<session_t> clients = m_clients.getClientIDs();
+		for (session_t client_id : clients) {
+			RemotePlayer *player = m_env->getPlayer(client_id);
+
+			// Get name of player
+			std::wstring name = L"unknown";
+			if (player)
+				name = narrow_to_wide(player->getName());
+
+			// Add name to information string
+			if (!first)
+				os << L", ";
+			else
+				first = false;
+
+			os << name;
+		}
 	os << L"}";
-	if(((ServerMap*)(&m_env->getMap()))->isSavingEnabled() == false)
-		os<<std::endl<<L"# Server: "<<" WARNING: Map saving is disabled.";
-	if(g_settings->get("motd") != "")
-		os<<std::endl<<L"# Server: "<<narrow_to_wide(g_settings->get("motd"));
+		if (m_env && !((ServerMap*)(&m_env->getMap()))->isSavingEnabled())
+		os << std::endl << L"# Server: " << " WARNING: Map saving is disabled.";
+	if (!g_settings->get("motd").empty())
+		os << std::endl << L"# Server: " << narrow_to_wide(g_settings->get("motd"));
 	return os.str();
 }