ensure that regcomp() errors get logged by having regerror()
syslog them, and by having smtpd capture send's stderr
and logging it even if send's exit status is good.

i also changed "smtpd" to "smtpd.db" for the log file for -d output;
feel free to keep or discard that change.

Reference: /n/sources/patch/applied/smtpd-log-recomp-errs
Date: Wed Nov 16 03:31:40 CET 2005

--- /sys/src/cmd/upas/smtp/smtpd.c	Wed Nov 16 03:31:13 2005
+++ /sys/src/cmd/upas/smtp/smtpd.c	Wed Nov 16 03:31:07 2005
@@ -157,7 +157,7 @@
 
 	if(debug){
 		close(2);
-		snprint(buf, sizeof(buf), "%s/smtpd", UPASLOG);
+		snprint(buf, sizeof(buf), "%s/smtpd.db", UPASLOG);
 		if (open(buf, OWRITE) >= 0) {
 			seek(2, 0, 2);
 			fprint(2, "%d smtpd %s\n", getpid(), thedate());
@@ -1221,6 +1221,16 @@
 		}
 		reply("%d mail process terminated abnormally\r\n", code);
 	} else {
+		/*
+		 * if a message appeared on stderr, despite good status,
+		 * log it.  this can happen if rewrite.in contains a bad
+		 * r.e., for example.
+		 */
+		if(*s_to_c(err))
+			syslog(0, "smtpd",
+				"%s returned good status, but said: %s",
+				s_to_c(mailer), s_to_c(err));
+
 		if(filterstate == BLOCKED)
 			reply("554 we believe this is spam.  we don't accept it.\r\n");
 		else
--- /sys/src/cmd/upas/send/rewrite.c	Wed Nov 16 03:31:24 2005
+++ /sys/src/cmd/upas/send/rewrite.c	Wed Nov 16 03:31:22 2005
@@ -282,6 +282,8 @@
 regerror(char* s)
 {
 	fprint(2, "rewrite: %s\n", s);
+	/* make sure the message is seen locally */
+	syslog(0, "mail", "error in rewrite: %s", s);
 }
 
 extern void