我是Firebase Hosting的新手，正在尝试为本地现有的项目提供服务，但出现以下错误：
[debug] [2018-10-11T13:26:23.359Z] Error: EACCES: permission denied, mkdir '/usr/local/lib/node_modules/firebase-tools/node_modules/@google-cloud/functions-emulator/logs'
at Object.fs.mkdirSync (fs.js:885:18)
at Object.assertLogsPath (/usr/local/lib/node_modules/firebase-tools/node_modules/@google-cloud/functions-emulator/src/emulator/logs.js:65:10)
at new Controller (/usr/local/lib/node_modules/firebase-tools/node_modules/@google-cloud/functions-emulator/src/cli/controller.js:77:32)
at FunctionsEmulator.start (/usr/local/lib/node_modules/firebase-tools/lib/functionsEmulator.js:113:21)
at Object.start (/usr/local/lib/node_modules/firebase-tools/lib/serve/functions.js:9:29)
at /usr/local/lib/node_modules/firebase-tools/lib/serve/index.js:17:21
at arrayMap (/usr/local/lib/node_modules/firebase-tools/node_modules/lodash/lodash.js:639:23)
at Function.map (/usr/local/lib/node_modules/firebase-tools/node_modules/lodash/lodash.js:9556:14)
at _serve (/usr/local/lib/node_modules/firebase-tools/lib/serve/index.js:15:7)
at Command._action (/usr/local/lib/node_modules/firebase-tools/commands/serve.js:47:12)
[error]
[error] Error: An unexpected error has occurred.
有人能说明我做错了什么吗？