From 7abcbe80e51a1d1fd70e2788ea7e4011a872abad Mon Sep 17 00:00:00 2001
From: Ed Ralston <ed@groknull.com>
Date: Thu, 19 May 2022 20:01:57 -0400
Subject: [PATCH] Prevent segfault in getCpuFrequency

When parseCpuFrequencies returns an empty vector, getCpuFrequency
would attempt to dereference an invalid iterator.

Return early from getCpuFrequency when parseCpuFrequencies returns an
empty vector.

Resolves a segfault when waybar is run within a VM on apple silicon.
---
 src/modules/cpu/common.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/modules/cpu/common.cpp b/src/modules/cpu/common.cpp
index 9fc58211..e46b74af 100644
--- a/src/modules/cpu/common.cpp
+++ b/src/modules/cpu/common.cpp
@@ -94,6 +94,10 @@ std::tuple<std::vector<uint16_t>, std::string> waybar::modules::Cpu::getCpuUsage
 
 std::tuple<float, float, float> waybar::modules::Cpu::getCpuFrequency() {
   std::vector<float> frequencies = parseCpuFrequencies();
+  if (frequencies.empty())
+  {
+    return {0.f, 0.f, 0.f};
+  }
   auto [min, max] = std::minmax_element(std::begin(frequencies), std::end(frequencies));
   float avg_frequency =
       std::accumulate(std::begin(frequencies), std::end(frequencies), 0.0) / frequencies.size();