Make port scans non-blocking

3 years ago · e6823edde7
parent 4f0bbfc667
commit e6823edde7
1 changed files with 3 additions and 2 deletions
--- a/5
+++ b/5
@ -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