On Tue, Feb 09, 2021 at 07:21:40PM +0200, Adrian Sevcenco wrote:

Hi! Does anyone have an idea how can i (in a nice way [1]) to ensure ownership/permissions of log directory in /var/log for a unit that drops privileges to a user (with User=/Group=)

[1] The ugly way being with script in StartPre and sudo in Start so i want to use User= I'm aware of LogsDirectory= but is not available on EL7

Running sudo in a systemd service seems like a bad idea and should be avoided. It'll require disabling the RequireTTY feature in the sudo configuration anyway.

Newer versions of systemd support adding a + or ! at the beginning of the ExecStart= command to tell systemd to run with elevated privileges, so you could have:

[Service] Type=oneshot User=testuser ExecStartPre=!mkdir -p /var/log/test ExecStartPre=!chown testuser /var/log/test ExecStart=/bin/sh -c 'date > /var/log/test/test.log'

However, those features aren't introduced into systemd until ~v231 so it isn't in EL7.

I think you will have to do something like:

ExecStartPre=mkdir -p /var/log/test ExecStartPre=chown testuser /var/log/test ExecStart=su testuser -c 'date > /var/log/test/test.log'

Just don't use sudo.

Hi! Does anyone have an idea how can i (in a nice way [1]) to ensure ownership/permissions of log directory in /var/log for a unit that drops privileges to a user (with User=/Group=)

[1] The ugly way being with script in StartPre and sudo in Start so i want to use User= I'm aware of LogsDirectory= but is not available on EL7

Hi Adrian,

I think such a fundamental lack should be addressed by adding it by upstream. Did you try to create a BZ so that this could be fixed? I guess a backport for systemd should help.

Regards, Simon