以用户身份存储守护程序的pid文件

Question

Is there a preferred place to store a pid file for a daemon that's run as a user? /var/run is the standard place, but this is for a user daemon so it doesn't have write privileges there. Presumably my daemon will be started from .profile or .bashrc or something. Is just saving it to /tmp a bad idea?

Answer 1

If it's being run for a user, let's see, what sort of storage exists that is user-specific.

Hmmm.

That's it! The home directory. I knew it would come to me eventually :-)

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Sorry for the light jab. Seriously, I would just stash the PID into $HOME/.daemon.pid or ~/.daemon.pid (how you name the file is up to you of course).

This is, of course, assuming you will only have one daemon running for a user. If not, you'll need to be a bit trickier.

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And hopefully allaying your fears that a user will inadvertently delete unknown files in their home directory, that's why you make it "hidden" by starting it with a . character.

Most non-experienced users should never even see these and experienced users should know better than to muck about with them.

Answer 2

The XDG Basedir specification defines where you should store these.
The variable $XDG_RUNTIME_DIR defines it's location, although it has no default.
The most common fallback (if the variable is unset) is /tmp/service-$USER.id .

This helps keep uncluttered homedirs, while keeping all runtime data in

Answer 3

I suggest you go for a subdirectory within the user's home directory.

~/.programname/.pid

If there is any other user configuration data, you can store that in here too, in order to avoid cluttering up the home directory.