libs/sys: extend luci.sys.hostname() to allow setting a new name

modules/admin-{full,mini}: update the hostname at runtime

libs/sys/luasrc/sys.lua

@@ -129,10 +129,16 @@ end
 -- @return		Table containing all variables if no variable name is given
 getenv = posix.getenv
 
---- Determine the current hostname.
+--- Get or set the current hostname.
+-- @param		String containing a new hostname to set (optional)
 -- @return		String containing the system hostname
-function hostname()
+function hostname(newname)
-	return posix.uname("%n")
+	if type(newname) == "string" and #newname > 0 then
+		luci.fs.writefile( "/proc/sys/kernel/hostname", newname .. "\n" )
+		return newname
+	else
+		return posix.uname("%n")
+	end
 end
 
 --- Returns the contents of a documented referred by an URL.

modules/admin-full/luasrc/model/cbi/admin_system/system.lua

@@ -47,7 +47,13 @@ s:option(DummyValue, "_systime", translate("m_i_systemtime")).value =
 s:option(DummyValue, "_uptime", translate("m_i_uptime")).value =
  luci.tools.webadmin.date_format(tonumber(uptime))
 
-s:option(Value, "hostname", translate("hostname"))
+hn = s:option(Value, "hostname", translate("hostname"))
+
+function hn.write(self, section, value)
+	Value.write(self, section, value)
+	luci.sys.hostname(value)
+end
+
 
 tz = s:option(ListValue, "zonename", translate("timezone"))
 tz:value("UTC")

modules/admin-mini/luasrc/model/cbi/mini/system.lua

@@ -50,7 +50,13 @@ s:option(DummyValue, "_systime", translate("m_i_systemtime")).value =
 s:option(DummyValue, "_uptime", translate("m_i_uptime")).value =
  luci.tools.webadmin.date_format(tonumber(uptime))
 
-s:option(Value, "hostname", translate("hostname"))
+hn = s:option(Value, "hostname", translate("hostname"))
+
+function hn.write(self, section, value)
+	Value.write(self, section, value)
+	luci.sys.hostname(value)
+end
+
 
 tz = s:option(ListValue, "zonename", translate("timezone"))
 tz:value("UTC")