SMGR/Crontab Problem on 3B1 kills newsrun
Rob Stampfli
res at colnet.uucp
Thu Feb 7 16:51:42 AEST 1991
I have just been experimenting with a problem I had with cnews running on
an AT&T Unix-PC (3B1) (3.51m OS). Occasionally, newsrun would terminate
prematurely, leaving partially uncompressed files. No news was lost -- the
problem was self correcting on the next invocation of newsrun. It did leave
partially uncompressed news files in the incoming news directory, though.
I traced this problem to the use of the <MSG> key on the console -- apparently
all processes attached to w5 (SMGR) get the SIGINT signal (Signal 2) each time
the <MSG> key on the console is depressed! The scenerio goes like this:
Newsrun comes across a control message and sends the news administrator (me)
mail. I am on the console and press <MSG> to see what the mail is. Newsrun
gets SIGINT, and terminates.
I have changed newsrun to ignore signal 2. Since newsrun is a shell script,
this was fairly easy to do.
Obviously, this is not a cnews problem. Cnews merely makes the SMGR bug more
visible due to the long-running nature of its crontab scripts. I post this
to the the news.software.b group only to warn 3B1 users of cnews who might
not otherwise see this.
For us 3B1 owners, I think we need to investigate what the full implications
of this phenomenon are. Obviously, the use of the <MSG> key can interfere
with the execution of crontab processes if they are not explicitly protected.
Anyone have any ideas?
--
Rob Stampfli, 614-864-9377, res at kd8wk.uucp (osu-cis!kd8wk!res), kd8wk at n8jyv.oh
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