From 0b87fde89cd6030681e984f2cf31177f378d7f90 Mon Sep 17 00:00:00 2001
From: Vladimir Kirillov <proger@wilab.org.ua>
Date: Tue, 12 Apr 2016 18:13:43 +0300
Subject: [PATCH] Try to detect hostapd early to prevent passing zero arguments
 to strings

In case hostapd is not installed, strings got stuck trying to read stdin.
---
 create_ap | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/create_ap b/create_ap
index 2c70285..4ab74b4 100755
--- a/create_ap
+++ b/create_ap
@@ -1292,8 +1292,15 @@ if ! can_be_sta_and_ap ${WIFI_IFACE}; then
     fi
 fi
 
+HOSTAPD=$(which hostapd)
+
+if ! -x "$HOSTAPD"; then
+    echo "ERROR: hostapd not found." >&2
+    exit 1
+fi
+
 if [[ $(get_adapter_kernel_module ${WIFI_IFACE}) =~ ^(8192[cd][ue]|8723a[sue])$ ]]; then
-    if ! strings $(which hostapd) | grep -m1 rtl871xdrv > /dev/null 2>&1; then
+    if ! strings "$HOSTAPD" | grep -m1 rtl871xdrv > /dev/null 2>&1; then
         echo "ERROR: You need to patch your hostapd with rtl871xdrv patches." >&2
         exit 1
     fi
@@ -1773,7 +1780,7 @@ if [[ $NO_HAVEGED -eq 0 ]]; then
 fi
 
 # start hostapd (use stdbuf for no delayed output in programs that redirect stdout)
-stdbuf -oL hostapd $HOSTAPD_DEBUG_ARGS $CONFDIR/hostapd.conf &
+stdbuf -oL $HOSTAPD $HOSTAPD_DEBUG_ARGS $CONFDIR/hostapd.conf &
 HOSTAPD_PID=$!
 echo $HOSTAPD_PID > $CONFDIR/hostapd.pid