From a2d75a7a992ac14a970fc9dc14ee21a71ee95b45 Mon Sep 17 00:00:00 2001
From: Ahurac <ahurac@mailbox.org>
Date: Wed, 27 Mar 2024 10:41:22 +0100
Subject: [PATCH] =?UTF-8?q?first-free-port=20:=20r=C3=A9=C3=A9criture=20en?=
 =?UTF-8?q?=20shell?=
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---
 qemu/bin/first-free-port | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100755 qemu/bin/first-free-port

diff --git a/qemu/bin/first-free-port b/qemu/bin/first-free-port
new file mode 100755
index 0000000..886a367
--- /dev/null
+++ b/qemu/bin/first-free-port
@@ -0,0 +1,34 @@
+#!/usr/bin/env sh
+#set -x
+
+name=$(basename "$0")
+used_tcp_ports=$(sed 1d /proc/net/tcp \
+    | awk '($4 == "0A") { print $2 }' \
+    | awk -F : '($1 == "00000000" || $1 == "0100007F") { print $2 }' \
+    | perl -e 'foreach my $line (<>) { print hex($line) . "\n"; }'
+)
+
+perror() {
+  >&2 printf "%s: %s\n" "$name" "$*"
+}
+
+port_is_free() {
+  for used_port in $used_tcp_ports; do
+    [ "$port" = "$used_port" ] && return 1
+  done
+
+  :
+}
+
+port=$1
+
+if ! { [ "$port" -gt 0 ] && [ "$port" -lt 65536 ]; } 2> /dev/null; then
+  perror "you must specify a valid TCP port"
+  exit 1
+fi
+
+while ! port_is_free; do
+  port=$((port + 1))
+done
+
+printf %s\\n "$port"