Sendmail 8.13.3 Programmer's Guide

Milter APIs
Data Access APIs
Chapter 2 23
#include <libmilter/mfapi.h>
int smfi_setmlreply(
SMFICTX *ctx,
char *rcode,
char *xcode,
...
);
Following are some points to consider regarding smfi_setmlreply():
• Values passed to smfi_setmlreply() are not checked for standards
compliance.
• The message parameter must contain only printable characters;
other characters can result in a undefined behavior. For example, CR
or LR causes the call to fail, a single % (percentage) character causes
the text to be ignored (if a % is required in a string, use %% similar to
the usage in printf (3)).
• If the reply code (rcode) is 4XX but SMFI-REJECT is used for the
message, the custom reply is not used.
Similarly, if the reply code (rcode)is5XX code but SMFI_TEMPFAIL is
used for the message, the custom reply is not used.
NOTE An error is not returned to the Milter program in neither of the
previous two cases; libmilter silently ignores the reply code.
For details about reply codes and their meanings, see RFC 821 or
2821, and RFC 1893 or RFC 2034.
• If the Milter program returns SMFI_TEMPFAIL and sets the reply code
to 421, the SMTP server terminates the SMTP session with a 421
error code.
Arguments
You must call smfi_setmlreply() with the following argument:
ctx Specifies an opaque context structure.
rcode Specifies the 3-digit SMTP reply code as specified in
RFC 821 (Simple Mail Transfer Protocol) or 2821
(Simple Mail Transfer Protocol). rcode is a
null-terminated string and must be a valid 4XX or 5XX
reply code. You must not set rcode to a NULL value.