chapter 13 exercises

Chapter 13 exercises

As we might guess from , when the syslog facility is initialized, either by calling openlog directly or on the first call to syslog, the special device file for the UNIX domain datagram socket, /dev/log, has to be opened. What happens if the user process (the daemon) calls chroot before calling openlog?

答案： 就不能正确打开那个文件了，建议使用LOG_NDELAY

call openlog with an option of LOG_NDELAY, before calling chroot

Write a program that calls the daemonize function in . After calling this function, call getlogin () to see whether the process has a login name now that it has become a daemon. Print the results to a file.

答案：成为daemon之后，没有了controlling terminnal，这样getlogin就不能依据conrolling terminal去查看utmp文件从而找到login name了。当然有的实现可能不是这样的。在linux和solaris就查不出来，但是在Free BSD和Mac中，login name被记录在了process table entry中。因此还是可以不通过controlling terminal来查到login name的。