Disengaging imsgev is tricky. First imsgev_clear as we know there isn't anything left to be written. Signal imsgev termination by setting iev->terminate = 1(Mind that we are setting it from with the callback). As imsgev would again callback dispatch with IMSGEV_DONE, we cannot free imsgev yet. So iev_maildrop need to exist beyond lifetime of session until IMSGEV_DONE. Allocating it seperately from session. imsgev_close is avoided as it schedules another EV_WRITE which is not needed in our case. This fixes a crash observed consistently with a little perl script to simulate concurrent sessions. Thanks MALLOC_OPTIONS='SFG<<'

pop3d
=====

POP3 Daemon with POP3S, STARTTLS extensions. Supports maildir, mbox formats.
Presently builds and runs only on OpenBSD.