requests, default to the previous 60-seconds scheduling method
unless there is any @every_second entries to conserve CPU cycles and
power.
This change also improves scheduling in the default mode by running
as close to the beginning of the minnute as possible by replacing
sleep(3) with nanosleep(2). Previously, the tasks would run anywhere
within the first second of the minute and that offset drifted back
and forth each time cron(8) was engaged.
MFC after: 1 month
only available via the new @every_second shortcut. ENOTIME to
implement crontab(5) format extensions to allow more flexible
scheduling.
In order to address some concerns expressed by Terry Lambert
while discussing the topic few years ago, about per-second cron
possibly causing some bad effects on /etc/crontab by stat()ing
it every second instead of every minute now (i.e. atime update),
only check that database needs to be reloaded on every 60-th
loop run. This should be close enough to the current behaviour.
Add "@every_minute" shortcut while I am here.
MFC after: 1 month
This structure is not part of POSIX. According to POSIX, gettimeofday()
has the following prototype:
int gettimeofday(struct timeval *restrict tp, void *restrict tzp);
Also, POSIX states that gettimeofday() shall return 0 (as long as tzp is
not used). Remove dead error handling code. Also use NULL for a
nul-pointer instead of integer 0.
While there, change all pieces of code that only use tv_sec to use
time(3), as this provides less overhead.
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
"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
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 patch Matthew submitted, but I broke the lines in a more FreeBSD
way and made one small wording change.
PR: 31265
Submitted by: Matthew D. Fuller <fullermd@over-yonder.net>
MFC after: 3 weeks
