luci-base: add a strict flag to the hostname validator

Some applications, e.g. dnsmasq, do not allow hostnames starting with an
underscore, therefor extend the existing hostname datatype validator with
a `strict` which disallows a leading underscore.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

2 files changed, 6 insertions, 5 deletions

diff --git a/modules/luci-base/htdocs/luci-static/resources/cbi.js b/modules/luci-base/htdocs/luci-static/resources/cbi.js
index d40ec34bc..6c35372cd 100644
--- a/modules/luci-base/htdocs/luci-static/resources/cbi.js
+++ b/modules/luci-base/htdocs/luci-static/resources/cbi.js
@@ -218,12 +218,13 @@ var cbi_validators = {
 			((ipv4only == 1) && cbi_validators.ip4addr.apply(this));
 	},
 
-	'hostname': function()
+	'hostname': function(strict)
 	{
 		if (this.length <= 253)
-			return (this.match(/^[a-zA-Z0-9]+$/) != null ||
+			return (this.match(/^[a-zA-Z0-9_]+$/) != null ||
 			        (this.match(/^[a-zA-Z0-9_][a-zA-Z0-9_\-.]*[a-zA-Z0-9]$/) &&
-			         this.match(/[^0-9.]/)));
+			         this.match(/[^0-9.]/))) &&
+			       (!strict || !this.match(/^_/));
 
 		return false;
 	},
diff --git a/modules/luci-base/luasrc/cbi/datatypes.lua b/modules/luci-base/luasrc/cbi/datatypes.lua
index 55cdf8a74..99113e0b7 100644
--- a/modules/luci-base/luasrc/cbi/datatypes.lua
+++ b/modules/luci-base/luasrc/cbi/datatypes.lua
@@ -199,13 +199,13 @@ function macaddr(val)
 	return ip.checkmac(val) and true or false
 end
 
-function hostname(val)
+function hostname(val, strict)
 	if val and (#val < 254) and (
 	   val:match("^[a-zA-Z_]+$") or
 	   (val:match("^[a-zA-Z0-9_][a-zA-Z0-9_%-%.]*[a-zA-Z0-9]$") and
 	    val:match("[^0-9%.]"))
 	) then
-		return true
+		return (not strict or not val:match("^_"))
 	end
 	return false
 end