Support --mkconfig option

When invoked with --mkconfig <conf_file>, the options are stored in
conf_file and create_ap exits.

bash_completion

@@ -2,6 +2,14 @@
 # Bash Completion routine for create_ap
 #
 
+_use_filedir() {
+    if [[ $(type -t _filedir) == "function" ]]; then
+        _filedir
+        return 0
+    fi
+    return 1
+}
+
 _create_ap() {
     local awk_cmd='
         ($1 ~ /^-/) {
@@ -117,6 +125,9 @@ _create_ap() {
         --list)
             # No Options
             ;;
+        --mkconfig)
+            _use_filedir && return 0
+            ;;
         -g)
             # Not going to implement
             ;;

create_ap

@@ -57,6 +57,7 @@ usage() {
     echo "                          you can put the PID of create_ap or the WiFi interface. You can"
     echo "                          get them with --list"
     echo "  --list                  Show the create_ap processes that are already running"
+    echo "  --mkconfig <conf_file>  Store configs in conf_file"
     echo
     echo "Non-Bridging Options:"
     echo "  -g <gateway>            IPv4 Gateway for the Access Point (default: 192.168.12.1)"
@@ -574,14 +575,21 @@ IEEE80211N=0
 HT_CAPAB='[HT40+]'
 DRIVER=nl80211
 NO_VIRT=0
-FIX_UNMANAGED=0
 COUNTRY=
 FREQ_BAND=2.4
 NEW_MACADDR=
 DAEMONIZE=0
+NO_HAVEGED=0
+
+CONFIG_OPTS=(CHANNEL GATEWAY WPA_VERSION ETC_HOST HIDDEN SHARE_METHOD
+             IEEE80211N HT_CAPAB DRIVER NO_VIRT COUNTRY FREQ_BAND
+             NEW_MACADDR DAEMONIZE NO_HAVEGED)
+
+FIX_UNMANAGED=0
 LIST_RUNNING=0
 STOP_ID=
-NO_HAVEGED=0
+
+STORE_CONFIG=
 
 CONFDIR=
 WIFI_IFACE=
@@ -806,8 +814,31 @@ send_stop() {
     mutex_unlock
 }
 
+# Storing configs
+write_config() {
+    local i=1
+
+    if ! eval 'echo -n > "$STORE_CONFIG"' > /dev/null 2>&1; then
+        echo "ERROR: Unable to create config file $STORE_CONFIG" >&2
+        exit 1
+    fi
+
+    for config_opt in "${CONFIG_OPTS[@]}"; do
+        eval echo $config_opt=\$$config_opt
+    done >> "$STORE_CONFIG"
+
+    while [[ $# -ne 0 ]]; do
+        echo "ARG$i=$1"
+        shift
+        ((i++))
+    done >> "$STORE_CONFIG"
+
+    echo -e "\nConfigs written to $STORE_CONFIG"
+    exit 0
+}
+
 ARGS=( "$@" )
-GETOPT_ARGS=$(getopt -o hc:w:g:dnm: -l "help","hidden","ieee80211n","ht_capab:","driver:","no-virt","fix-unmanaged","country:","freq-band:","mac:","daemon","stop:","list","version","no-haveged" -n "$PROGNAME" -- "$@")
+GETOPT_ARGS=$(getopt -o hc:w:g:dnm: -l "help","hidden","ieee80211n","ht_capab:","driver:","no-virt","fix-unmanaged","country:","freq-band:","mac:","daemon","stop:","list","version","no-haveged","mkconfig:" -n "$PROGNAME" -- "$@")
 [[ $? -ne 0 ]] && exit 1
 eval set -- "$GETOPT_ARGS"
 
@@ -908,6 +939,11 @@ while :; do
             shift
             NO_HAVEGED=1
             ;;
+        --mkconfig)
+            shift
+            STORE_CONFIG="$1"
+            shift
+            ;;
         --)
             shift
             break
@@ -934,6 +970,8 @@ trap "clean_exit" SIGINT SIGUSR1
 # if we get USR2 signal then run die().
 trap "die" SIGUSR2
 
+[[ -n "$STORE_CONFIG" ]] && write_config "$@"
+
 if [[ $LIST_RUNNING -eq 1 ]]; then
     echo -e "List of running $PROGNAME instances:\n"
     list_running