James wrote: > -> If i'm playing round with user's mailboxes, do i need to somehow lock > -> them? > - > -Yes. > - > -When manipulating mail spools, you should generally use both a > -lockfile and fcntl(). > - > -To create a lockfile, create a file in the spool directory, link() it > -to <username>.lock, and unlink() the original. This is the only method > -which is reliable over NFS. > > so what i do is: > > make some file in the spool dir.(using mktemp() or similar?) > link that file to <name_of_mail_spool>.lock > [do various nasty things to the mail spool :) ] > unlink the .lock file > delete the temp file > > this right? You would typically delete the temp file after you've link()ed it to <whatever>.lock, but apart from that, yes. > the lock file doesn't need to contain any data does it? No. > it's just there as a marker for other things to check the existance > of? Yes. > What happens if some other program (sendmail, procmail etc) tries to > fiddle with the locked mail spool, do they just hang around waiting? Yes, although procmail will apparently override the lockfile after a certain amount of time. However, fcntl() locks won't be (can't be) overriden. -- Glynn Clements <[EMAIL PROTECTED]>
