Index: usr.sbin/jls/jls.8
===================================================================
--- usr.sbin/jls/jls.8
+++ usr.sbin/jls/jls.8
@@ -104,7 +104,11 @@
 containing the following parameters:
 jail identifier (jid), hostname (host.hostname), path (path),
 jail name (name), jail state (dying), cpuset ID (cpuset),
-IP address(es) (ip4.addr and ip6.addr).
+IP address(es) (ip4.addr and ip6.addr, one address per line).
+.Pp
+For encoding-styled
+.Sy --libxo
+output, IPv4 and IPv6 addresses emitted as separate lists.
 .It Fl j Ar jail
 The jid or name of the
 .Ar jail
Index: usr.sbin/jls/jls.c
===================================================================
--- usr.sbin/jls/jls.c
+++ usr.sbin/jls/jls.c
@@ -51,7 +51,7 @@
 #define	JP_USER		0x01000000
 #define	JP_OPT		0x02000000
 
-#define JLS_XO_VERSION	"1"
+#define JLS_XO_VERSION	"2"
 
 #define	PRINT_DEFAULT	0x01
 #define	PRINT_HEADER	0x02
@@ -77,7 +77,9 @@
 static char *noname(const char *name);
 static char *nononame(const char *name);
 static int print_jail(int pflags, int jflags);
+static int special_print(int pflags, struct jailparam *param);
 static void quoted_print(int pflags, char *name, char *value);
+static void emit_ip_addr(int af_family, struct jailparam *param);
 
 int
 main(int argc, char **argv)
@@ -379,8 +381,7 @@
 {
 	char *nname, *xo_nname;
 	char **param_values;
-	int i, ai, jid, count, n, spc;
-	char ipbuf[INET6_ADDRSTRLEN];
+	int i, jid, n, spc;
 
 	jid = jailparam_get(params, nparams, jflags);
 	if (jid < 0)
@@ -401,29 +402,17 @@
 		n = 6;
 #ifdef INET
 		if (ip4_ok && !strcmp(params[n].jp_name, "ip4.addr")) {
-			count = params[n].jp_valuelen / sizeof(struct in_addr);
-			for (ai = 0; ai < count; ai++)
-				if (inet_ntop(AF_INET,
-				    &((struct in_addr *)params[n].jp_value)[ai],
-				    ipbuf, sizeof(ipbuf)) == NULL)
-					xo_err(1, "inet_ntop");
-				else {
-					xo_emit("{P:        }{l:ipv4_addrs}{P:\n}", ipbuf);
-				}
+			xo_open_list("ipv4_addrs");
+			emit_ip_addr(AF_INET, params + n);
+			xo_close_list("ipv4_addrs");
 			n++;
 		}
 #endif
 #ifdef INET6
 		if (ip6_ok && !strcmp(params[n].jp_name, "ip6.addr")) {
-			count = params[n].jp_valuelen / sizeof(struct in6_addr);
-			for (ai = 0; ai < count; ai++)
-				if (inet_ntop(AF_INET6,
-				    &((struct in6_addr *)
-					params[n].jp_value)[ai],
-				    ipbuf, sizeof(ipbuf)) == NULL)
-					xo_err(1, "inet_ntop");
-				else
-					xo_emit("{P:        }{l:ipv6_addrs}{P:\n}", ipbuf);
+			xo_open_list("ipv6_addrs");
+			emit_ip_addr(AF_INET6, params + n);
+			xo_close_list("ipv6_addrs");
 			n++;
 		}
 #endif
@@ -450,6 +439,7 @@
 			if (!(params[i].jp_flags & JP_USER))
 				continue;
 			param_values[i] = jailparam_export(params + i);
+			param_values[i] = jailparam_export(params + i);
 			if (param_values[i] == NULL)
 				xo_errx(1, "%s", jail_errmsg);
 		}
@@ -499,14 +489,10 @@
 				}
 				xo_emit("{d:%s}=", params[i].jp_name);
 			}
-			if (params[i].jp_valuelen == 0) {
-				if (pflags & PRINT_QUOTED)
-					xo_emit("{P:\"\"}");
-				else if (!(pflags & PRINT_NAMEVAL))
-					xo_emit("{P:-}");
-			} else {
+
+			if (!special_print(pflags, params + i))
 				quoted_print(pflags, params[i].jp_name, param_values[i]);
-			}
+
 		}
 		xo_emit("{P:\n}");
 		for (i = 0; i < nparams; i++)
@@ -553,3 +539,72 @@
 	if (qc && pflags & PRINT_QUOTED)
 		xo_emit("{P:/%c}", qc);
 }
+
+static int
+special_print(int pflags, struct jailparam *param) {
+
+	int ip_as_list;
+
+	switch (xo_get_style(NULL)) {
+		case XO_STYLE_JSON:
+		case XO_STYLE_XML:
+			ip_as_list = 1;
+			break;
+		default:
+			ip_as_list = 0;
+	}
+
+	if (!ip_as_list && param->jp_valuelen == 0) {
+		if (pflags & PRINT_QUOTED)
+			xo_emit("{P:\"\"}");
+		else if (!(pflags & PRINT_NAMEVAL))
+			xo_emit("{P:-}");
+	} else if (ip_as_list && !strcmp(param->jp_name, "ip4.addr")) {
+		xo_open_list("ip4.addr");
+		emit_ip_addr(AF_INET, param);
+		xo_close_list("ip4.addr");
+	} else if (ip_as_list && !strcmp(param->jp_name, "ip6.addr")) {
+		xo_open_list("ip6.addr");
+		emit_ip_addr(AF_INET6, param);
+		xo_close_list("ip6.addr");
+	}  else {
+		return 0;
+	}
+
+	return 1;
+}
+
+static void
+emit_ip_addr(int af_family, struct jailparam *param) {
+	char ipbuf[INET6_ADDRSTRLEN];
+	size_t addr_len;
+	const char *emit_str;
+	int count, ai;
+
+	switch (af_family) {
+		case AF_INET:
+			addr_len = sizeof(struct in_addr);
+			emit_str = "{P:        }{ql:ipv4_addr}{P:\n}";
+			break;
+		case AF_INET6:
+			addr_len = sizeof(struct in6_addr);
+			emit_str = "{P:        }{ql:ipv6_addr}{P:\n}";
+			break;
+		default:
+			xo_err(1, "unsupported af_family");
+			return;
+	}
+
+	count = param->jp_valuelen / addr_len;
+
+	for (ai = 0; ai < count; ai++) {
+		if (inet_ntop(af_family,
+			      ((uint8_t*)param->jp_value) + addr_len*ai,
+			      ipbuf, sizeof(ipbuf)) == NULL) {
+			xo_err(1, "inet_ntop");
+		} else {
+			xo_emit(emit_str, ipbuf);
+		}
+	}
+
+}