Do I properly understand that it is not possible to run /etc/cron.daily/my from arbitrary user, it will be run only from root according to /etc/crontab?
Can I drop root privilege to specific user in my cron scrip instead?
It is better to place cron job into /etc/cron.d? Like:
$ cat /etc/cron.d/my
5 0 * * * user test -x /usr/bin/my && /usr/bin/my -cfg /etc/my.cfg
You are right, the jobs in /etc/cron.daily (and weekly/monthly, etc.) are always
executed as user root but you can simply swith the user from within the script
and call that very script again as that other user, including all supplied
arguments (although there won't be any in a cron.daily job):
File /etc/cron.daily/my:
#!/bin/sh
# If started as root, then re-start as user "gavenkoa":
if [ "$(id -u)" -eq 0 ]; then
exec sudo -H -u gavenkoa $0 "$@"
echo "This is never reached.";
fi
echo "This runs as user $(id -un)";
# prints "gavenkoa"
exit 0;
When the script is started as user root it will detect so and
re-execute itself via sudo -H -u gavenkoa, that is: as
user gavenkoa. This requires no special entries in /etc/sudoers
because root is always allowed to switch to any user.
The exec replaces the current process with the new sudo … call
and never returns. That's why you don't need an else clause.
sudoisn't POSIX utils. Issuavailable in all UNIXes? – gavenkoa Dec 30 '18 at 13:32sudois always installed. But if you prefersuinstead, you can of course replace thesudocall withsubut be aware that it's more complicated to pass the arguments"$@"tosu, see Pass arguments to a command run by another user over on U&L. – PerlDuck Dec 30 '18 at 14:02