On Sunday, 22 August 1999 at 17:31:44 -0700, Matthew Dillon wrote: > >> Questions: >> >> 1. Do we have some form of mandatory locking? If so, what is it? > > No we don't, unless you count the ad-hoc lockout in the master/slave pty > interface :-). > >> 2. Would it make sense to implement System V's fcntl semantics? >> They're rather tacky: you set the setgid bit and reset the group >> exec bit of the file permissions. > > Ugh. Yuch. No, nothing to do with permission bits, not for something > this convoluted!
I don't like it either, but for compatibility reasons it would make sense. That's why I suggested a sysctl knob. >> 3. Alternatively (or additionally), would it make sense to have an >> additional fcntl function which performs mandatory locking? >> >> I think that it's probably a good idea to implement (3), and also to >> do (2), possibly subject to a sysctl knob. > > Well, #3 can't be mandatory if you have to make a fcntl call! Somehow you need to get a lock. > You mean have one program make a fcntl call that causes other > programs to return an error or block if they try to open that > file while the first program holds an open descriptor? Correct. I suppose it's worth discussing what the default should be. Should they get EAGAIN or block? Obviously you'd want a way of specifying which, but there would have to be a default for non-lock-aware programs. I think I'd go for blocking; it's less error prone. Greg -- See complete headers for address, home page and phone numbers finger g...@lemis.com for PGP public key To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
