Enhance Linux startup script.

sample-config/shadowsocks

@@ -21,64 +21,92 @@ CONFIG_FILE=/etc/shadowsocks/config.json
 LOG_FILE=/var/log/shadowsocks
 USER=nobody
 GROUP=nobody
-PID_DIR=/var/run/
+PID_DIR=/var/run
 PID_FILE=$PID_DIR/shadowsocks.pid
 RET_VAL=0
 
+check_running() {
+  if [[ -r $PID_FILE ]]; then
+    read PID <$PID_FILE
+    if [[ -d "/proc/$PID" ]]; then
+      return 0
+    else
+      rm -f $PID_FILE
+      return 1
+    fi
+  else
+    return 2
+  fi
+}
+
+do_status() {
+  check_running
+  case $? in
+    0)
+      echo "shadowsocks running with PID $PID"
+      ;;
+    1)
+      echo "shadowsocks not running, remove PID file $PID_FILE"
+      ;;
+    2)
+      echo "Could not find PID file $PID_FILE, shadowsocks does not appear to be running"
+      ;;
+  esac
+  return 0
+}
+
+do_start() {
+  if [[ ! -d $PID_DIR ]]; then
+    echo "creating PID dir"
+    mkdir $PID_DIR || echo "failed creating PID directory $PID_DIR"; exit 1
+    chown $USER:$GROUP $PID_DIR || echo "failed creating PID directory $PID_DIR"; exit 1
+    chmod 0770 $PID_DIR
+  fi
+  if check_running; then
+    echo "shadowsocks already running with PID $PID"
+    return 0
+  fi
+  if [[ ! -r $CONFIG_FILE ]]; then
+    echo "config file $CONFIG_FILE not found"
+    return 1
+  fi
+  echo "starting shadowsocks"
+  # sudo will set the group to the primary group of $USER
+  sudo -u $USER $BIN -c $CONFIG_FILE >>$LOG_FILE &
+  PID=$!
+  echo $PID > $PID_FILE
+  sleep 0.3
+  if ! check_running; then
+    echo "start failed, log file $LOG_FILE may provide some help"
+    return 1
+  fi
+  echo "shadowsocks running with PID $PID"
+  return 0
+}
+
+do_stop() {
+  if check_running; then
+    echo "stopping shadowsocks with PID $PID"
+    kill $PID
+    rm -f $PID_FILE
+  else
+    echo "Could not find PID file $PID_FILE"
+  fi
+}
+
+do_restart() {
+  do_stop
+  do_start
+}
+
 case "$1" in
-    start)
-      if [[ ! -d $PID_DIR ]]
-      then
-        mkdir $PID_DIR
-        chown $USER:$GROUP $PID_DIR
-        chmod 0770 $PID_DIR
-      fi
-      if [[ -r $PID_FILE ]]
-      then
-        echo "shadowsocks already running with PID `cat $PID_FILE`"
-        RET_VAL=1
-      else
-        # sudo will set the group to the primary group of $USER
-        sudo -u $USER $BIN -c $CONFIG_FILE >$LOG_FILE &
-        echo $! > $PID_FILE
-        RET_VAL=$?
-      fi
-  ;;
-    stop)
-      if [[ -r $PID_FILE ]]
-      then
-        kill `cat $PID_FILE`
-        rm $PID_FILE
-        RET_VAL=$?
-      else
-        echo "Could not find PID file $PID_FILE"
-        RET_VAL=1
-      fi
-  ;;
-    restart)
-      if [[ -r $PID_FILE ]]
-      then
-        kill `cat $PID_FILE`
-        rm $PID_FILE
-        RET_VAL=$?
-      else
-        echo "Could not find PID file $PID_FILE"
-      fi
-      start
-      RET_VAL=$?
-  ;;
-    status)
-      if [[ -r $PID_FILE ]]
-      then
-        echo "shadowsocks running with PID `cat $PID_FILE`"
-        RET_VAL=$?
-      else
-        echo "Could not find PID file $PID_FILE, shadowsocks does not appear to be running"
-      fi
-  ;;
-    *)
-      echo "Usage: shadowsocks {start|stop|restart|status}"
-      RET_VAL=1
-  ;;
+  start|stop|restart|status)
+    do_$1
+    ;;
+  *)
+    echo "Usage: shadowsocks {start|stop|restart|status}"
+    RET_VAL=1
+    ;;
 esac
+
 exit $RET_VAL