occurs in the same second as the earlier operations to create the temporary
file and the cron(8) daemon is rescans the spool directory during that
second, then the daemon may miss a cron edit and not properly update its
internal database.
MFC after: 1 month
DST should not need to worry about scheduling jobs when the DST time
changes.
Rather than removing the BUGS section in crontab(5) regarding this,
note that disabling '-s' may still cause jobs to be executed twice or
not at all.
PR: 166318
Submitted by: Florian k Unglaub (f.unglaub%googlemail!com)
MFC After: 1 week
environments.
Please note that this can't be done while such processes run in jails.
Note: in future it would be interesting to find a way to do that
selectively for any desired proccess (choosen by user himself), probabilly
via a ptrace interface or whatever.
Obtained from: Sandvine Incorporated
Reviewed by: emaste, arch@
Sponsored by: Sandvine Incorporated
MFC: 1 month
unless explicitly provided by MAILTO= line in crontab. This feature can be
useful in massive hosting environment, where most users do not care about
autogenerated mails.
Setting recipient to null string disables default mails at all.
Approved by: yar
MFC after: 4 weeks
by unavailable accounts, e.g., those locked, expired, not allowed in at
the moment by nologin(5), or whatever, depending on cron's pam.conf(5).
This applies to personal crontabs only, /etc/crontab is unaffected.
In other words, now the account management policy will apply to
commands scheduled by users via crontab(1) so that a user can no
longer use cron(8) to set up a delayed backdoor and run commands
during periods when the admin doesn't want him to.
The PAM check is done just before running a command, not when loading
a crontab, because accounts can get locked, expired, and re-enabled
any time with no changes to their crontabs. E.g., imagine that you
provide a system with payed access, or better a cluster of such
systems with centralized account management via PAM. When a user
pays for some days of access, you set his expire field respectively.
If the account expires before its owner pays more, its crontab
commands won't run until the next payment is made. Then it'll be
enough to set the expire field in future for the commands to run
again. And so on.
Document this change in the cron(8) manpage, which includes adding
a FILES section and touching the document date.
X-Security: should benefit as users have access to cron(8) by default
as crontab(5) states it can be. This is supported by all vixie-cron derived
implementations; not sure why FreeBSD was any different.
PR: bin/106442
MFC after: 2 weeks
setgid(2), setlogin(2) and initgroups(3). In theory they could
fail for root with some third party mac(4) policies.
Submitted by: Kostik Belousov
MFC after: 1 month
"crontab /etc/crontab", but not the same format due to the who field.
Add some limited anti-foot-shooting support and refuse to load
/etc/crontab as someone's crontab. Users wishing shoot their foot in
this manner may copy /etc/crontab elsewhere. :)
MFC After: 1 week
Note, that when cron(8) cannot create pidfile, it'll exit. I didn't
changed this behaviour, but its better to ignore errors other than
EEXIST, so daemon can be started on systems where /var/ file system
doesn't support locking (like NFS without rpc.lockd(8)).
entry having stepping value of zero can cause crontab to hang there,
and if the main crontab is being changed in this way, then cron(8)
will keep spining.
Obtained from: OpenBSD [src/usr.sbin/cron/entry.c,v 1.17]
PR: 68683 (my own, but forgot to commit it...)
MFC After: 1 week
to PRECIOUSLIB from bsd.lib.mk. The side effect of this
is making installing the world under jail(8) possible by
using another knob, NOFSCHG.
Reviewed by: oliver
$ crontab -e
[Add an entry with an error in the crontab file.]
crontab: errors in crontab file, can't install
Do you want to retry the same edit? yes
[Exit the editor without any changes.]
crontab: no changes made to crontab
[Entry is lost.]
Now crontab will loop until the error is fixed, or the
user answers no.
the maximum amount of time jitter for root and other users, respectively.
Before starting a job, cron(8) will sleep a random number of seconds,
from 0 to the amount specified. This can help to smooth down load spikes
when a lot of jobs are to start at the beginning of a particular minute
(e.g., the first minute of an hour.)
PR: bin/66474
Submitted by: Dmitry Morozovsky <marck <@> rinet.ru>
