luci-base: luci.js: introduce hasSystemFeature() api

The new function allows querying the presence of certain system features
such as dnsmasq or firewall availability or the compile time features
of hostapd and wpa_supplicant.

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

modules/luci-base/htdocs/luci-static/resources/luci.js

@@ -559,6 +559,7 @@
 	    domParser = null,
 	    originalCBIInit = null,
 	    rpcBaseURL = null,
+	    sysFeatures = null,
 	    classes = {};
 
 	var LuCI = Class.extend({
@@ -797,6 +798,43 @@
 			return Promise.resolve(rpcBaseURL);
 		},
 
+		probeSystemFeatures: function() {
+			if (sysFeatures == null) {
+				try {
+					sysFeatures = JSON.parse(window.sessionStorage.getItem('sysFeatures'));
+				}
+				catch (e) {}
+			}
+
+			if (!this.isObject(sysFeatures)) {
+				sysFeatures = classes.rpc.declare({
+					object: 'luci',
+					method: 'getFeatures',
+					expect: { '': {} }
+				})().then(function(features) {
+					try {
+						window.sessionStorage.setItem('sysFeatures', JSON.stringify(features));
+					}
+					catch (e) {}
+
+					sysFeatures = features;
+
+					return features;
+				});
+			}
+
+			return Promise.resolve(sysFeatures);
+		},
+
+		hasSystemFeature: function() {
+			var ft = sysFeatures[arguments[0]];
+
+			if (arguments.length == 2)
+				return this.isObject(ft) ? ft[arguments[1]] : null;
+
+			return (ft != null && ft != false);
+		},
+
 		setupDOM: function(res) {
 			var domEv = res[0],
 			    uiClass = res[1],
@@ -828,10 +866,12 @@
 				throw 'Session expired';
 			});
 
+			return this.probeSystemFeatures().finally(this.initDOM);
+		},
+
+		initDOM: function() {
 			originalCBIInit();
-
 			Poll.start();
-
 			document.dispatchEvent(new CustomEvent('luci-loaded'));
 		},
 

modules/luci-base/root/usr/libexec/rpcd/luci

@@ -320,6 +320,92 @@ local methods = {
 
 			return { helpers = rv }
 		end
+	},
+
+	getFeatures = {
+		call = function()
+			local fs = require "nixio.fs"
+			local rv = {}
+			local ok, fd
+
+			rv.firewall      = fs.access("/sbin/fw3")
+			rv.opkg          = fs.access("/bin/opkg")
+			rv.offloading    = fs.access("/sys/module/xt_FLOWOFFLOAD/refcnt")
+			rv.br2684ctl     = fs.access("/usr/sbin/br2684ctl")
+			rv.swconfig      = fs.access("/sbin/swconfig")
+			rv.odhcpd        = fs.access("/usr/sbin/odhcpd")
+
+			local wifi_features = { "eap", "11n", "11ac", "11r", "11w", "acs", "sae", "owe", "suiteb192" }
+
+			if fs.access("/usr/sbin/hostapd") then
+				rv.hostapd = {}
+
+				local _, feature
+				for _, feature in ipairs(wifi_features) do
+					rv.hostapd[feature] =
+						(os.execute(string.format("/usr/sbin/hostapd -v%s >/dev/null 2>/dev/null", feature)) == 0)
+				end
+			end
+
+			if fs.access("/usr/sbin/wpa_supplicant") then
+				rv.wpasupplicant = {}
+
+				local _, feature
+				for _, feature in ipairs(wifi_features) do
+					rv.wpasupplicant[feature] =
+						(os.execute(string.format("/usr/sbin/wpa_supplicant -v%s >/dev/null 2>/dev/null", feature)) == 0)
+				end
+			end
+
+			ok, fd = pcall(io.popen, "dnsmasq --version 2>/dev/null")
+			if ok then
+				rv.dnsmasq = {}
+
+				while true do
+					local line = fd:read("*l")
+					if not line then
+						break
+					end
+
+					local opts = line:match("^Compile time options: (.+)$")
+					if opts then
+						local opt
+						for opt in opts:gmatch("%S+") do
+							local no = opt:match("^no%-(%S+)$")
+							rv.dnsmasq[string.lower(no or opt)] = not no
+						end
+						break
+					end
+				end
+
+				fd:close()
+			end
+
+			ok, fd = pcall(io.popen, "ipset --help 2>/dev/null")
+			if ok then
+				rv.ipset = {}
+
+				local sets = false
+
+				while true do
+					local line = fd:read("*l")
+					if not line then
+						break
+					elseif line:match("^Supported set types:") then
+						sets = true
+					elseif sets then
+						local set, ver = line:match("^%s+(%S+)%s+(%d+)")
+						if set and not rv.ipset[set] then
+							rv.ipset[set] = tonumber(ver)
+						end
+					end
+				end
+
+				fd:close()
+			end
+
+			return rv
+		end
 	}
 }
 

modules/luci-base/root/usr/share/rpcd/acl.d/luci-base.json

@@ -1,4 +1,13 @@
 {
+	"unauthenticated": {
+		"description": "Allow system feature probing",
+		"read": {
+			"ubus": {
+				"luci": [ "getFeatures" ]
+			}
+		}
+	},
+
 	"uci-access": {
 		"description": "Grant uci write access to all configurations",
 		"read": {