Linux守护进程：替代chdir（“ /”）？

Question

I have a program (Crafty chess) that works just fine when started from the console. For my application I have daemonized it. When daemonizing a process, one is supposed to change the working directory to "/" via chdir("/") .

When I follow that advice, the program exits in some use cases because it doesn't have the proper permissions in "/". When I don't chdir , the program works, but just leaving out chdir is a crutch.

Is there a sound alternative to omitting chdir("/") ?

Answer 1

It probably should not write to the current directory. It'd be better to write to some specific directory instead. Instead of cd'ing to /tmp and writing files to the current directory, write files to /tmp/whatever — ie always use absolute paths.

And on a related note, don't hardcode /tmp if you can avoid it. Make it a configuration option, or use the $TMPDIR environment variable, or best of all, use mktemp() .

Answer 2

You can call the daemon(3) function (with a non-zero first nochdir argument) so that it daemonize a process without doing the chdir("/") )

But as John Kugelman suggests, you should not write (nor read) any relative path in a daemonized program (or you should do an explicit chdir to a directory that you can read and write and search).