From 2fd6d209995e2466433db1a2e7f0b94ea35b3888 Mon Sep 17 00:00:00 2001
From: patrick96 <p.ziegler96@gmail.com>
Date: Wed, 3 Mar 2021 21:55:43 +0100
Subject: [PATCH] fix(xworkspaces): Segfault for wrong _NET_CURRENT_DESKTOP

While it shouldn't happen with compliant WMs, it was possibe to crash
polybar with _NET_CURRENT_DESKTOP >= _NET_NUMBER_OF_DESKTOPS and this
should not be possible.

Includes polybar/xpp#31
Fixes #2398
---
 include/modules/xworkspaces.hpp |  1 +
 lib/xpp                         |  2 +-
 src/modules/xworkspaces.cpp     | 15 +++++++++++----
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/include/modules/xworkspaces.hpp b/include/modules/xworkspaces.hpp
index f98d6465..17578502 100644
--- a/include/modules/xworkspaces.hpp
+++ b/include/modules/xworkspaces.hpp
@@ -71,6 +71,7 @@ namespace modules {
     void rebuild_urgent_hints();
     void rebuild_desktops();
     void rebuild_desktop_states();
+    void update_current_desktop();
 
     void action_focus(const string& data);
     void action_next();
diff --git a/lib/xpp b/lib/xpp
index 4d67025c..7a9960bb 160000
--- a/lib/xpp
+++ b/lib/xpp
@@ -1 +1 @@
-Subproject commit 4d67025cdbcc7f3c65d1a620c97a8443e0a08129
+Subproject commit 7a9960bbb912f0ed66929c978aaeb1c30acf4bfd
diff --git a/src/modules/xworkspaces.cpp b/src/modules/xworkspaces.cpp
index 2e78b371..e6c3cee4 100644
--- a/src/modules/xworkspaces.cpp
+++ b/src/modules/xworkspaces.cpp
@@ -95,8 +95,7 @@ namespace modules {
 
     // Get desktop details
     m_desktop_names = get_desktop_names();
-    m_current_desktop = ewmh_util::get_current_desktop();
-    m_current_desktop_name = m_desktop_names[m_current_desktop];
+    update_current_desktop();
 
     rebuild_desktops();
 
@@ -105,6 +104,15 @@ namespace modules {
     rebuild_desktop_states();
   }
 
+  void xworkspaces_module::update_current_desktop() {
+    m_current_desktop = ewmh_util::get_current_desktop();
+    if (m_current_desktop < m_desktop_names.size()) {
+      m_current_desktop_name = m_desktop_names[m_current_desktop];
+    } else {
+      throw module_error("The current desktop is outside of the number of desktops reported by the WM");
+    }
+  }
+
   /**
    * Handler for XCB_PROPERTY_NOTIFY events
    */
@@ -120,8 +128,7 @@ namespace modules {
       rebuild_clientlist();
       rebuild_desktop_states();
     } else if (evt->atom == m_ewmh->_NET_CURRENT_DESKTOP) {
-      m_current_desktop = ewmh_util::get_current_desktop();
-      m_current_desktop_name = m_desktop_names[m_current_desktop];
+      update_current_desktop();
       rebuild_desktop_states();
     } else if (evt->atom == WM_HINTS) {
       rebuild_urgent_hints();