From: Martijn van Duren <openbsd+tech@list.imperialat.at>
Subject: Re: smtpd: Give filters their own syslog tag
To: tech@openbsd.org
Date: Fri, 20 Feb 2026 12:44:16 +0100

On 2/20/26 10:18, Martijn van Duren wrote:
> EHLO,
> 
> A few months ago Leo Unglaub send me an e-mail asking about the position
> of the mail ID inside the syslog line, more specifically that we
> currently prepend the filter-name before it; Making it hard to find the
> ID with automated tools.
> 
> While I'm not a fan of automated parsing of log-files, there is
> something to say for having consistency in the placement, and not
> forcing in the filtername.
> 
> I would like to propose the following diff, making use of syslog_r to
> give every filter their own tag. Since tags can only have alpha-
> and up to 32 characters (RFC3164 section 4.1.3) I made it the default
> to use the first 32 alpha-characters from the filter-name, and if that
> result is too ugly an admin can use the new tag keyword to create their
> own one.
> 
> syslog_r isn't a portable function, but I've already discussed a couple
> of potential solutions with op@, so there shouldn't be any problems in
> that area.
> 
> OK?
> 
> martijn@
As a followup I would like to add the option to let filters specify the
loglevel per message. There's no value in specifying the global loglevel
on a per-filter basis via cli flags, and to let smtpd log them all as
LOG_WARNING.
It might be worthwhile to also send a config update when smtpctl
changes the loglevel to reduce the logmsg overhead for filters that
would support this, but that wouldn't make a functional difference and
outside the scope of this diff.

martijn@

diff d28c12b27e3c9e7a32cd929c1010839a90f63a6a 7e4994f30824f376c9581b937512172f7f3c1b9d
commit - d28c12b27e3c9e7a32cd929c1010839a90f63a6a
commit + 7e4994f30824f376c9581b937512172f7f3c1b9d
blob - f10652c2a482e0f9fbbf3d842e7389939eb8471a
blob + dae25dd933fae3a133a7efc9736907a5c296c446
--- usr.sbin/smtpd/lka_filter.c
+++ usr.sbin/smtpd/lka_filter.c
@@ -25,7 +25,7 @@
 #include "smtpd.h"
 #include "log.h"
 
-#define	PROTOCOL_VERSION	"0.7"
+#define	PROTOCOL_VERSION	"0.8"
 
 struct filter;
 struct filter_session;
@@ -323,7 +323,28 @@ processor_errfd(struct io *io, int evt, void *arg)
 	switch (evt) {
 	case IO_DATAIN:
 		while ((line = io_getline(io, &len)) != NULL) {
-			log_warnx_r(&processor->sd, "%s", line);
+			if (!strncasecmp(
+			    line, "DEBUG|", sizeof("DEBUG|") - 1))
+				log_debug_r(&processor->sd, "%s",
+				    line + sizeof("DEBUG|") - 1);
+			else if (!strncasecmp(
+			    line, "INFO|", sizeof("INFO|") - 1))
+				log_info_r(&processor->sd, "%s",
+				    line + sizeof("INFO|") - 1);
+			else if (!strncasecmp(
+			    line, "WARNING|", sizeof("WARNING|") - 1))
+				log_warnx_r(&processor->sd, "%s",
+				    line + sizeof("WARNING|") - 1);
+			else if (!strncasecmp(
+			    line, "WARN|", sizeof("WARN|") - 1))
+				log_warnx_r(&processor->sd, "%s",
+				    line + sizeof("WARN|") - 1);
+			else if (!strncasecmp(
+			    line, "FATAL|", sizeof("FATAL|") - 1))
+				logit_r(&processor->sd, LOG_CRIT, "%s",
+				    line + sizeof("FATAL|") - 1);
+			else
+				log_warnx_r(&processor->sd, "%s", line);
 		}
 	}
 }
blob - e9ca3ae6ff21edda39ae9dddb77d074f0b32b158
blob + 65516d91b5cbf4b9202f89c2bcf4bac7d9277635
--- usr.sbin/smtpd/log.c
+++ usr.sbin/smtpd/log.c
@@ -75,6 +75,16 @@ logit(int pri, const char *fmt, ...)
 }
 
 void
+logit_r(struct syslog_data *data, int pri, const char *fmt, ...)
+{
+	va_list	ap;
+
+	va_start(ap, fmt);
+	vlog_r(data, pri, fmt, ap);
+	va_end(ap);
+}
+
+void
 vlog(int pri, const char *fmt, va_list ap)
 {
 	vlog_r(NULL, pri, fmt, ap);
@@ -160,6 +170,16 @@ log_info(const char *emsg, ...)
 }
 
 void
+log_info_r(struct syslog_data *data, const char *emsg, ...)
+{
+	va_list	 ap;
+
+	va_start(ap, emsg);
+	vlog_r(data, LOG_INFO, emsg, ap);
+	va_end(ap);
+}
+
+void
 log_debug(const char *emsg, ...)
 {
 	va_list	 ap;
@@ -171,6 +191,18 @@ log_debug(const char *emsg, ...)
 	}
 }
 
+void
+log_debug_r(struct syslog_data *data, const char *emsg, ...)
+{
+	va_list	 ap;
+
+	if (verbose > 1) {
+		va_start(ap, emsg);
+		vlog_r(data, LOG_DEBUG, emsg, ap);
+		va_end(ap);
+	}
+}
+
 static void
 vfatalc(int code, const char *emsg, va_list ap)
 {
blob - c8da7731c0b6f4d510f3976a97291cecf8d39560
blob + da07847993c675bdbdae2d198412264df0ef05d8
--- usr.sbin/smtpd/log.h
+++ usr.sbin/smtpd/log.h
@@ -35,10 +35,16 @@ void	log_warnx_r(struct syslog_data *, const char *, .
 	    __attribute__((__format__ (printf, 2, 3)));
 void	log_info(const char *, ...)
 	    __attribute__((__format__ (printf, 1, 2)));
+void	log_info_r(struct syslog_data *, const char *, ...)
+	    __attribute__((__format__ (printf, 2, 3)));
 void	log_debug(const char *, ...)
 	    __attribute__((__format__ (printf, 1, 2)));
+void	log_debug_r(struct syslog_data *, const char *, ...)
+	    __attribute__((__format__ (printf, 2, 3)));
 void	logit(int, const char *, ...)
 	    __attribute__((__format__ (printf, 2, 3)));
+void	logit_r(struct syslog_data *, int, const char *, ...)
+	    __attribute__((__format__ (printf, 3, 4)));
 void	vlog(int, const char *, va_list)
 	    __attribute__((__format__ (printf, 2, 0)));
 void	vlog_r(struct syslog_data *, int, const char *, va_list)