or recommended for pro- duction use. Some features are missing on Windows (including multi-process mode) and scalability is limited (Even though Tornado is built on asyncio, which supports Windows, Tornado all other exceptions return a 500 status. The default error page includes a stack trace in debug mode and a one-line description of the error (e.g. “500: Internal Server Error”) otherwise. To produce ($query_string) { expires max; } } Debug mode and automatic reloading If you pass debug=True to the Application constructor, the app will be run in debug/development mode. In this mode, several features intended for

supported or recommended for production use. Some features are missing on Windows (including multi-process mode) and scalability is limited (Even though Tornado is built on asyncio, which supports Windows, Tornado Processes and ports Running behind a load balancerStatic files and aggressive file caching Debug mode and automatic reloadingIntroduction Tornado [http://www.tornadoweb.org] is a Python web framework all other exceptions return a 500 status. The default error page includes a stack trace in debug mode and a one-line description of the error (e.g. “500: Internal Server Error”) otherwise. To produce

问题3：文件系统访问控制是在哪一层实现的？ 二、文件系统权限管理 文件类型 文件权限 特殊权限(SUID, SGID, STICKY) 文件默认权限umask 用户&用户组 文件系统用户权限管理 对mode的管理 对ACL（Access Control Lists）的管理 ACL Access Entry保存在哪？ ACL的表示 内存中的ACL 是如何与具体的 Inode 相关联 如何存储和获取ACL信息 conf /tmp/fsmount 问题1：root用户无法访问挂载目录 测试发现client mount进程是哪个用户启动的就只有该用户(filesystem owner)可以访问该目录，即使挂载点mode是777。 # filesystem owner wanghai01@pubbeta1-nostest2:/tmp$ ls -l | grep fsmount drwxrwxrwx 0 root "allow_other,fd=9,rootmode=40000,"...) = 0 问题3：文件系统访问控制是在哪一层实现的？ 测试curvefs，发现文件系统链路默认是没有做权限控制。（挂载点mode 777） # mountpoint wanghai01@pubbeta1-nostest2:/tmp$ ls -l | grep fsmount drwxrwxrwx 0 root

int flags, mode_t mode); int creat(const char *pathname, mode_t mode); int openat(int dirfd, const char *pathname, int flags); int openat(int dirfd, const char *pathname, int flags, mode_t mode); int openat2(int 020000000|O_DIRECTORY #define O_NDELAY O_NONBLOCK(O_NDELAY是在System V的早期版本引入的，后改进为O_NONBLOCK) flags中必须access mode：O_RDONLY, O_WRONLY, O_RDWR其中之一；© XXX Page 4 of 23 文件创建标志只影响打开操作, 文件状态标志影响后面的读写操作 file creation flags: 为进程uid，gid为进程gid或父目录gid（取决于SGID是否置位）；当flags中出现O_CREAT 或 O_TMPFILE时，mode参数必须提供，否则会使用栈中随机字节填充；通常在没有ACL的情况下，有效的mode是经过与进程mask作用后的结果（mode & ~mask)。 # symbolic constants S_IRWXU 00700 S_IRUSR 00400 S_IWUSR

arguments inside scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 40.2 Parallel mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 40.3 Startup file CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it

arguments inside scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 40.2 Parallel mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 40.3 Startup file CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it

main entry point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529 41.3 Parallel mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530 41.4 Startup file CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it

main entry point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529 41.3 Parallel mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530 41.4 Startup file CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it

main entry point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529 41.3 Parallel mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530 41.4 Startup file CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it

main entry point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 41.3 Parallel mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541 41.4 Startup file CTRL-D (press the Control/^ key together with the d key), or type exit(). When run in interactive mode, julia displays a banner and prompts the user for input. Once the user has entered a complete expression learning resource by switching into the help mode. Switch to help mode by pressing ? at an empty julia> prompt, before typing anything else. Typing a keyword in help mode will fetch the documentation for it