another process already has /dev/snp0 open, the snp(4) will return
EBUSY, in which case watch will try to open /dev/snp1..9. Currently
watch does not check errno to see if the failure was a result of EBUSY.
This results in watch making futile attempts to open snp0..snp9 even
though devices may not exist or the caller does not have permissions
to access the device.
In addition to this, it attempts to setup the screen for snooping even
though it may not ever get an snp device.
So this patch does two things
1) Checks errno for EBUSY, if open(2) fails for another reason
print that reason and exit.
2) setup the terminal for snooping after the snp descriptor has
been obtained.
Approved by: bmilekic (mentor)
_PATH_DEV will never change. In the un-likely event that _PATH_DEV
should ever change, watch(8) would have broke because of a
mis-generated device name.
Approved by: bmilekic (mentor)
Pointed out by: Yvan Boily
return for getopt() and comparing to -1, ditto with fgetc() and EOF,
and using the kg_nice value from <sys/user.h>
Submitted by: Stefan Farfeleder <stefan@fafoe.narf.at>
Reviewed by: obrien, bde (a while back)
Tested lightly on: ppc, i386, make universe
Previously, watch would always use the first device it could
successfully open, but this isn't always desired. Specifically, it
may not be desired during debugging (of snp), or if a particular snp
device has different permissions (which makes since after snp.c 1.64).
change terminals being watched. This change makes watch pass the
<control-X> through to the terminal if it's not being intercepted--
previously, the keypress would simply be dropped.
2. fix a potential buffer oflow,
3. makes watch(8) conform to sysexits(3).
Not a strong 2.2 candidate even if it would be nice.
Reviewed by: joerg, imp
disables the ability to interactively select a new tty. I have also
removed a check for uid == 0 because it gets in the way of using suid
mode based access control. Watch (8)is only runnable by root, so this
does not really change things much.
Closes PR#2131
Submitted-By: adrian@virginia.edu
guys to a watched process. Useful if you're monitoring someone who's
started doing something you'd really like them to stop immediately. :)
Suggested by: Phillip White <philw@megasoft.tic.ab.ca>
