There is no global signal mask (like umask) for specific signals. In a script, you can choose to how to handle a signal such as SIGHUP, SIGQUIT, or SIGTERM by using the trap statement. The action specified by trap will be taken upon detection of the named signals, something like this:
trap "echo trap 2 or 3 seen" 2 3
So every time signals 1 2 or 3 (also known as kill signals) are sent to this script, it will just echo the message and continue on. Here's a sample script:
#!/usr/bin/sh
trap "echo Trap 2 3 or 15 seen" 2 3 15
while :
do
sleep 1
done
Run the script and from another session, issue kill commands -2 -3 or -15 and you'll see the program detect them. Use kill -1 to terminal the script (CTRL-C won't work as it is kill -15)
As for Oracle ignoring the signal(s), IF the signal was sent to an Oracle process, then the process is ignoring the signal and would have to be rewritten and recompiled to fix the problem. If the signal is being sent to a parent process, same requirement.
If the parent process is a shell script, make sure the script is using trap correctly. If no traps are in the script, does the script get started as an su login? Aha! Is the logfile full of login junk like the copyright message? This means that /etc/profile and .profile need some work.
Start by looking at /etc/profile: is there a trap command? If yes, is there a second? HP standard /etc/profile has two and they MUST exist in a pair:
trap "" 1 2 3
trap 1 2 3
If the second trap is missing (some sysadmins remove because it looks redundant) then subsequent activities spawned by the login shell will no longer respond to traps 1 2 or 3. The first statement: trap "" 1 2 3 means: do nothing if these traps are seen. The second statement: trap 1 2 3 will reanable standard behavior.
So make sure that all traps starting at the highest level are set and reset as required.
BTW: To fix all that extra login junk (including "not a typewriter' error messages, any command in a script that is interactive or terminal-based must be skipped when there is no terminal (such as cron jobs or start/stop scripts). The usual suspects are: tabs ttytype tput and of course: cat /etc/copyright.
In /etc/profile (and .profile if needed), test for interactive with:
if [ -o interactive ]
then
...do things like tput or tabs or cat /etc/copyright
fi
Now the interactive commands will only be run when there is a true interactive terminal in control of the session.
Bill Hassell, sysadmin
