From e6823edde7c4a5c341bd5b26db24eac615989bbd Mon Sep 17 00:00:00 2001
From: Martin Wimpress <code@flexion.org>
Date: Fri, 3 Dec 2021 11:33:41 +0000
Subject: [PATCH] Make port scans non-blocking

---
 quickemu | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/quickemu b/quickemu
index 7d38cb5..54b1e5e 100755
--- a/quickemu
+++ b/quickemu
@@ -136,8 +136,9 @@ function get_port() {
     local PORT_RANGE=$((PORT_START+$2))
     local PORT
     for ((PORT = PORT_START; PORT <= PORT_RANGE; PORT++)); do
-        (echo -n "" >/dev/tcp/127.0.0.1/"${PORT}") >/dev/null 2>&1
-        if [ ${?} -ne 0 ]; then
+        # Make sure port scans do not block too long.
+        timeout 0.1s bash -c "echo >/dev/tcp/127.0.0.1/${PORT}" >/dev/null 2>&1
+        if [ ${?} -eq 1 ]; then
             echo "${PORT}"
             break
         fi