Check every 2 seconds if haveged is needed

README.md

@@ -13,6 +13,7 @@
 ### General
 * bash (to run this script)
 * util-linux (for getopt)
+* procps or procps-ng
 * hostapd
 * iproute2
 * iw

create_ap

@@ -3,6 +3,7 @@
 # general dependencies:
 #    bash (to run this script)
 #    util-linux (for getopt)
+#    procps or procps-ng
 #    hostapd
 #    iproute2
 #    iw
@@ -40,6 +41,7 @@ usage() {
     echo "  --freq-band <GHz>   Set frequency band. Valid inputs: 2.4, 5 (default: 2.4)"
     echo "  --driver            Choose your WiFi adapter driver (default: nl80211)"
     echo "  --no-virt           Do not create virtual interface"
+    echo "  --no-haveged        Do not run \`haveged' automatically when needed"
     echo "  --fix-unmanaged     If NetworkManager shows your interface as unmanaged after you"
     echo "                      close create_ap, then use this option to switch your interface"
     echo "                      back to managed"
@@ -267,6 +269,29 @@ get_new_macaddr() {
     echo $NEWMAC
 }
 
+# start haveged when needed
+haveged_watchdog() {
+    local show_warn=0
+    while :; do
+        if [[ $(cat /proc/sys/kernel/random/entropy_avail) -lt 1000 ]]; then
+            if ! which haveged > /dev/null 2>&1; then
+                if [[ $show_warn -eq 0 ]]; then
+                    echo "WARN: Low entropy detected. We recommend you to install \`haveged'"
+                    show_warn=1
+                fi
+            elif ! pidof haveged > /dev/null 2>&1; then
+                echo "Low entropy detected, starting haveged"
+                # boost low-entropy
+                haveged -w 1024 -F > /dev/null 2>&1 &
+                local haveged_pid=$!
+                echo $haveged_pid > $CONFDIR/haveged.pid
+                wait $haveged_pid
+            fi
+        fi
+        sleep 2
+    done
+}
+
 NETWORKMANAGER_CONF=/etc/NetworkManager/NetworkManager.conf
 NM_OLDER_VERSION=1
 
@@ -422,6 +447,7 @@ NEW_MACADDR=
 DAEMONIZE=0
 LIST_RUNNING=0
 STOP_ID=
+NO_HAVEGED=0
 
 CONFDIR=
 WIFI_IFACE=
@@ -434,10 +460,15 @@ OLD_MACADDR=
 IP_ADDRS=
 ROUTE_ADDRS=
 
+HAVEGED_WATCHDOG_PID=
+
 _cleanup() {
     trap "" SIGINT
     trap "" SIGUSR1
 
+    # kill haveged_watchdog
+    [[ -n "$HAVEGED_WATCHDOG_PID" ]] && kill $HAVEGED_WATCHDOG_PID
+
     # exiting
     for x in $CONFDIR/*.pid; do
         # even if the $CONFDIR is empty, the for loop will assign
@@ -574,7 +605,7 @@ trap "clean_exit" SIGINT
 trap "clean_exit" SIGUSR1
 
 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" -n $(basename $0) -- "$@")
+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 $(basename $0) -- "$@")
 [[ $? -ne 0 ]] && exit 1
 eval set -- "$GETOPT_ARGS"
 
@@ -671,6 +702,10 @@ while :; do
             shift
             LIST_RUNNING=1
             ;;
+        --no-haveged)
+            shift
+            NO_HAVEGED=1
+            ;;
         --)
             shift
             break
@@ -1122,13 +1157,6 @@ else
     echo "No Internet sharing"
 fi
 
-# boost low-entropy
-if [[ $(cat /proc/sys/kernel/random/entropy_avail) -lt 1000 ]]; then
-    which haveged > /dev/null 2>&1 && {
-        haveged -w 1024 -p $CONFDIR/haveged.pid
-    }
-fi
-
 # start dns + dhcp server
 if [[ "$SHARE_METHOD" != "bridge" ]]; then
     iptables -I INPUT -p tcp -m tcp --dport 53 -j ACCEPT || die
@@ -1144,6 +1172,12 @@ echo "hostapd command-line interface: hostapd_cli -p $CONFDIR/hostapd_ctrl"
 trap "clean_exit" SIGINT
 trap "clean_exit" SIGUSR1
 
+if [[ $NO_HAVEGED -eq 0 ]]; then
+    haveged_watchdog &
+    HAVEGED_WATCHDOG_PID=$!
+fi
+
+# start hostapd
 hostapd $CONFDIR/hostapd.conf &
 HOSTAPD_PID=$!
 echo $HOSTAPD_PID > $CONFDIR/hostapd.pid