Replaced Windows registry lookup with WMIC process invocation. (#115)

composer.json

@@ -36,11 +36,12 @@
     "require": {
         "php": ">=8.1",
         "ext-filter": "*",
+        "ext-json": "*",
         "amphp/amp": "^3",
         "amphp/byte-stream": "^2",
         "amphp/cache": "^2",
         "amphp/parser": "^1",
-        "amphp/windows-registry": "^1.0.1",
+        "amphp/process": "^2",
         "daverandom/libdns": "^2.0.2",
         "revolt/event-loop": "^1 || ^0.2"
     },

src/WindowsDnsConfigLoader.php

@@ -4,89 +4,67 @@
 
 use Amp\ForbidCloning;
 use Amp\ForbidSerialization;
-use Amp\WindowsRegistry\KeyNotFoundException;
-use Amp\WindowsRegistry\WindowsRegistry;
+use Amp\Process\Process;
+use function Amp\ByteStream\buffer;
 
 final class WindowsDnsConfigLoader implements DnsConfigLoader
 {
     use ForbidCloning;
     use ForbidSerialization;
 
-    private const NETWORK_CARDS_KEY =
-        'HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\NetworkCards';
-    private const TCPIP_PARAMETERS_KEY =
-        'HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces';
-
     public function __construct(
         private readonly HostLoader $hostLoader = new HostLoader(),
     ) {
     }
 
     public function loadConfig(): DnsConfig
     {
-        $keys = [
-            "HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\NameServer",
-            "HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\DhcpNameServer",
-        ];
-
-        $nameserver = "";
-
-        while ($nameserver === "" && ($key = \array_shift($keys))) {
-            try {
-                $nameserver = WindowsRegistry::read($key);
-            } catch (KeyNotFoundException) {
-                // retry other possible locations
-            }
-        }
-
-        if ($nameserver === "") {
-            foreach (self::findNetworkCardGuids() as $guid) {
-                foreach (["NameServer", "DhcpNameServer"] as $property) {
-                    try {
-                        $nameserver = WindowsRegistry::read(self::TCPIP_PARAMETERS_KEY . "\\$guid\\$property");
-
-                        if ($nameserver !== "") {
-                            break 2;
-                        }
-                    } catch (KeyNotFoundException) {
-                        // retry other possible locations
-                    }
-                }
-            }
-        }
+        $wmic = Process::start(['wmic', 'NICCONFIG', 'GET', 'DNSServerSearchOrder']);
 
-        if ($nameserver === "") {
-            throw new DnsConfigException("Could not find a nameserver in the Windows Registry");
+        if ($wmic->join() !== 0) {
+            throw new DnsConfigException("Could not fetch DNS servers from WMI: " . buffer($wmic->getStderr()));
         }
 
-        $nameservers = [];
+        $ips = self::parseWmicOutput(buffer($wmic->getStdout()));
 
-        // Comma is the delimiter for the NameServer key, but space is used for the DhcpNameServer key.
-        foreach (\explode(" ", \strtr($nameserver, ",", " ")) as $nameserver) {
-            $nameserver = \trim($nameserver);
-            $ip = \inet_pton($nameserver);
-
-            if ($ip === false) {
-                continue;
-            }
+        $nameservers = \array_reduce($ips, static function (array $nameservers, string $address): array {
+            $ip = \inet_pton($address);
 
             if (isset($ip[15])) { // IPv6
-                $nameservers[] = "[" . $nameserver . "]:53";
-            } else { // IPv4
-                $nameservers[] = $nameserver . ":53";
+                $nameservers[] = "[$address]:53";
+            } elseif (isset($ip[3])) { // IPv4
+                $nameservers[] = "$address:53";
             }
-        }
+
+            return $nameservers;
+        }, []);
 
         $hosts = $this->hostLoader->loadHosts();
 
         return new DnsConfig($nameservers, $hosts);
     }
 
-    private static function findNetworkCardGuids(): array
+    private static function parseWmicOutput(string $output): array
     {
-        return \array_map(
-            static fn (string $key): string => WindowsRegistry::read("$key\\ServiceName"),
-            WindowsRegistry::listKeys(self::NETWORK_CARDS_KEY),
+        // Massage WMIC output into JSON format.
+        $json = \preg_replace(
+            [
+                // Convert header line into opening bracket.
+                '[^\V*\v+]',
+                // Convert closing braces into commas.
+                '[}]',
+                // Remove final comma.
+                '[,(?=[^,]*+$)]',
+                // Removing opening braces.
+                '[{]',
+            ],
+            [
+                '[',
+                ',',
+            ],
+            $output,
         );
+
+        return \json_decode("$json]", true, flags: \JSON_THROW_ON_ERROR);
     }
 }