sendmail, 4th Edition

Milter smfi_quarantine()

Quarantine a message V8.13 and later

V8.13 sendmail added a routine called smfi_quarantine() to the Milter library. It is used to quarantine (rather than to simply accept or reject) a message. Quarantining is described in Queue Quarantining on page 438.

This new routine may only be called from the xxfi_eom() (Milter xxfi_eom() on page 1215) end-of-message handling routine. But before you can use this smfi_quarantine() routine, you must declare your intention to do so by first adding the SMFIF_QUARANTINE flag to the flags part of the smfiDesc declaration:

struct smfiDesc smfilter =
{
    ...
    SMFIF_ADDHDRS|SMFIF_QUARANTINE,    /* flags */   ← add here

Note that the flags are bitwise-ORed together (the “|” character). Once this is done, you can use this new smfi_quarantine() routine inside your xxfi_eom() routine, like this:

ret = smfi_quarantine(ctx, reason);

The smfi_quarantine() routine’s first argument is a common context pointer, ctx. The next argument is reason, a string that will be recorded in the queue as the reason this message was quarantined. The string must be non-NULL and not empty.

For example, suppose your Milter screens for viruses and one was found:

ret = smfi_quarantine(ctx, "Possible virus found in message body");

The return value (the ret) will be MI_SUCCESS on success; otherwise it will be MI_FAILURE. This smfi_quarantine() routine can fail if reason is NULL or empty, or if there was a network error, or if SMFIF_QUARANTINE was not set in your smfiDesc