Schedule local deliveries
qmail-lspawn defaultdelivery
qmail-lspawn reads a series of local delivery commands from descriptor 0, invokes qmail-local to perform the deliveries, and prints the results to descriptor 1. It passes defaultdelivery to qmail-local as the default delivery instruction.
qmail-lspawn invokes qmail-local asynchronously, so the results may not be in the same order as the commands.
For each recipient address, qmail-lspawn finds out which local user controls that address. It first checks the qmail-users mechanism; if the address is not listed there, it invokes qmail-getpw. qmail-lspawn then runs qmail-local under the user's uid and gid. It does not set up any supplementary groups.
qmail-lspawn treats an empty mailbox name as a trash address.