--- usr.sbin/syslogd/syslogd.c.orig	2019-11-23 01:36:17.347873000 +0100
+++ usr.sbin/syslogd/syslogd.c	2020-02-24 13:59:47.102903000 +0100
@@ -133,6 +133,7 @@
 #include <fnmatch.h>
 #include <libutil.h>
 #include <limits.h>
+#include <locale.h>
 #include <netdb.h>
 #include <paths.h>
 #include <signal.h>
@@ -141,8 +142,11 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sysexits.h>
+#include <uchar.h>
 #include <unistd.h>
 #include <utmpx.h>
+#include <vis.h>
+#include <wctype.h>
 
 #include "pathnames.h"
 #include "ttymsg.h"
@@ -734,6 +738,9 @@
 	/* tuck my process id away */
 	pidfile_write(pfh);
 
+	/* set the character set locale */
+	setlocale(LC_CTYPE, getenv("LC_CTYPE"));
+
 	dprintf("off & running....\n");
 
 	tvp = &tv;
@@ -911,28 +918,38 @@
 static void
 parsemsg_remove_unsafe_characters(const char *in, char *out, size_t outlen)
 {
-	char *q;
+	const char *p;
+	char *q, *end_q;
 	int c;
+	size_t n;
 
+	p = in;
 	q = out;
-	while ((c = (unsigned char)*in++) != '\0' && q < out + outlen - 4) {
-		if (mask_C1 && (c & 0x80) && c < 0xA0) {
-			c &= 0x7F;
-			*q++ = 'M';
-			*q++ = '-';
+	end_q = out + outlen - 1;
+	while (*p != '\0' && q < end_q) {
+		n = mbrtoc32(&c, p, (size_t)MB_LEN_MAX, NULL);
+		if (n == 0)
+			break;
+		if (n < 0 || n > (size_t)MB_LEN_MAX) {
+			/* Invalid char sequence for this charset. */
+			c = *p;
+			n = (size_t)1;
 		}
-		if (isascii(c) && iscntrl(c)) {
-			if (c == '\n') {
-				*q++ = ' ';
-			} else if (c == '\t') {
-				*q++ = '\t';
-			} else {
-				*q++ = '^';
-				*q++ = c ^ 0100;
-			}
+		if (c == '\n') {
+			*q++ = ' ';
+		} else if (c == '\t') {
+			*q++ = '\t';
+		} else if (iswprint(c)) {
+			if (q > end_q - n)
+				break;
+			strncpy(q, p, n);
+			q += n;
 		} else {
-			*q++ = c;
+			if (q > end_q - 4)
+				break;
+			q = vis(q, c, 0, 0);
 		}
+		p += n;
 	}
 	*q = '\0';
 }