Add switch --list-clients

--list-clients <id> prints the list of connected clients associated with
<id>. <id> can either be a wifi iface name or pid of a create_ap
instance.

bash_completion

@@ -128,6 +128,10 @@ _create_ap() {
         --list-running)
             # No Options
             ;;
+        --list-clients)
+            local clients_awk_cmd='$1 ~ /^[0-9]+$/'
+            opts=$("$1" --list-running | awk "$clients_awk_cmd")
+            ;;
         --mkconfig)
             _use_filedir && return 0
             ;;

create_ap

@@ -58,6 +58,9 @@ usage() {
     echo "                          you can put the PID of create_ap or the WiFi interface. You can"
     echo "                          get them with --list-running"
     echo "  --list-running          Show the create_ap processes that are already running"
+    echo "  --list-clients <id>     List the clients connected to create_ap instance associated with <id>"
+    echo "                          For an <id> you can put the PID of create_ap or the WiFi interface."
+    echo "                          You can get them with --list-running"
     echo "  --mkconfig <conf_file>  Store configs in conf_file"
     echo "  --config <conf_file>    Load configs from conf_file"
     echo
@@ -593,6 +596,7 @@ CONFIG_OPTS=(CHANNEL GATEWAY WPA_VERSION ETC_HOSTS HIDDEN SHARE_METHOD
 FIX_UNMANAGED=0
 LIST_RUNNING=0
 STOP_ID=
+LIST_CLIENTS_ID=
 
 STORE_CONFIG=
 LOAD_CONFIG=
@@ -780,6 +784,80 @@ list_running() {
     mutex_unlock
 }
 
+list_clients_iface() {
+    local IFACE pid x
+    mutex_lock
+    for x in /tmp/create_ap.*; do
+        if [[ -f $x/pid ]]; then
+            pid=$(cat $x/pid)
+            if [[ -d /proc/$pid && "$LIST_CLIENTS_ID" -eq $pid ]]; then
+                IFACE=${x#*.}
+                IFACE=${IFACE%%.*}
+                echo $IFACE
+                break
+            fi
+        fi
+    done
+    mutex_unlock
+}
+
+list_clients_leaseinfo() {
+    local line lease_flag=0 count="$1" mac="$2"
+    local awk_cmd='{printf "%-20s %-18s %s\n", $2, $3, $4}'
+
+    while read line; do
+        if [[ "$mac" == "$(echo $line | awk '{print $2}')" ]]; then
+            printf "%2s  " "$count"
+            echo $line | awk "$awk_cmd"
+            lease_flag=1
+            break
+        fi
+    done < /var/lib/misc/dnsmasq.leases
+
+    if [[ $lease_flag -eq 0 ]]; then
+        printf "%-20s %-18s %s\n" "$x" "*" "*"
+    fi
+}
+
+list_clients() {
+    # If PID is given, get the associated wifi iface
+    if [[ "$LIST_CLIENTS_ID" =~ ^[1-9][0-9]*$ ]]; then
+        local iface=$(list_clients_iface)
+
+        if [[ -n "$iface" ]]; then
+            LIST_CLIENTS_ID="$iface"
+        else
+            echo "ERROR: '$LIST_CLIENTS_ID' is not the pid of a running $PROGNAME instance" >&2
+            exit 1
+        fi
+    fi
+
+    if ! is_wifi_interface "$LIST_CLIENTS_ID"; then
+        echo "ERROR: '$LIST_CLIENTS_ID' is not a WiFi interface." >&2
+        exit 1
+    fi
+
+    if [[ $USE_IWCONFIG -eq 0 ]]; then
+        local awk_cmd='($1 ~ /Station$/) {print $2}'
+        local client_list=$(iw dev "$LIST_CLIENTS_ID" station dump | awk "$awk_cmd")
+
+        if [[ -z "$client_list" ]]; then
+            echo "No clients connected"
+        else
+            printf "%3s %-20s %-18s %s\n" "" "MAC" "IP" "Hostname"
+        fi
+
+        local mac count=1
+        for mac in $client_list; do
+            list_clients_leaseinfo $count $mac
+            ((count++))
+        done
+    else
+        echo "ERROR: This option is not supported for the current driver" >&2
+        exit 1
+    fi
+}
+
 has_running_instance() {
     local PID x
 
@@ -891,7 +969,7 @@ for ((i=0; i<$#; i++)); do
     fi
 done
 
-GETOPT_ARGS=$(getopt -o hc:w:g:dnm: -l "help","hidden","ieee80211n","ht_capab:","driver:","no-virt","fix-unmanaged","country:","freq-band:","mac:","daemon","stop:","list","list-running","version","psk","no-haveged","mkconfig:","config:" -n "$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","list-running","list-clients:","version","psk","no-haveged","mkconfig:","config:" -n "$PROGNAME" -- "$@")
 [[ $? -ne 0 ]] && exit 1
 eval set -- "$GETOPT_ARGS"
 
@@ -993,6 +1071,11 @@ while :; do
             shift
             LIST_RUNNING=1
             ;;
+        --list-clients)
+            shift
+            LIST_CLIENTS_ID="$1"
+            shift
+            ;;
         --no-haveged)
             shift
             NO_HAVEGED=1
@@ -1032,7 +1115,8 @@ if [[ -n "$LOAD_CONFIG" && $# -eq 0 ]]; then
 fi
 
 # Check if required number of positional args are present
-if [[ $# -lt 1 && $FIX_UNMANAGED -eq 0  && -z "$STOP_ID" && $LIST_RUNNING -eq 0 ]]; then
+if [[ $# -lt 1 && $FIX_UNMANAGED -eq 0  && -z "$STOP_ID" &&
+      $LIST_RUNNING -eq 0 && -z "$LIST_CLIENTS_ID" ]]; then
     usage >&2
     exit 1
 fi
@@ -1058,6 +1142,11 @@ if [[ $LIST_RUNNING -eq 1 ]]; then
     exit 0
 fi
 
+if [[ -n "$LIST_CLIENTS_ID" ]]; then
+    list_clients
+    exit 0
+fi
+
 if [[ $(id -u) -ne 0 ]]; then
     echo "You must run it as root." >&2
     exit 1