bzs@bu-cs.arpa (Barry Shein) (10/27/86)
This one has never bit me before, perhaps it's been beaten to death (this all applies under both 4.2 and SYS/V I believe.) Your news software (for example) is all nicely set up so everything is setuid'd to pseudo-user news (eg. inews.) A user, trying to be a good citizen, puts a file size limit of, oh, 2M into his/her/its .login/.profile. An attempt to post news fails with a Filesize Limit Exceeded because of the inherited file size limit. I haven't tried to trace this down so perhaps it's something else, but that's the basic symptoms and my (outside) diagnosis. Makes sense to me, but seems like a real design problem, no? Surely if this is the case a) it's a bad reason to make all the news [or whatever] software setuid root and b) it's a bad reason for the user to remove his/her/its file size limit. The only fix I can think of off hand is to wrap the news commands in a setuid root 'shell' which then su to news after fixing the various limits, but it sure seems to be a lurking nuisance (that is, what else needs to be fixed like this so as not to bite hard on nice users?) Just thought you'd appreciate something else to worry about. -Barry Shein, Boston University P.S. The actual problem was exhibited on a SUN Release 3.0 but I am pretty sure it's generic to all 4.2/SYSV.
richl@penguin.UUCP (10/28/86)
The problems of SIGXFSZ and SIGXCPU are similar. Like SIGTSTP and SIGTTOU when they first appeared, many programs aren't prepared to handle them. Basically any program which opens a log file may succumb to this problem. If the log file gets too big ... poof. We've run into this in the past with both news and mail. Simple fix, of course, is to ignore both signals. This does not require root priviledges, but solves the problem nicely. (Unless you aren't a source site, of course!) Rick Lindsley