Replace basic auth with PHP session login

auth.php

@@ -0,0 +1,62 @@
+<?php
+const MVLOG_AUTH_CONFIG = '/etc/mvlog/auth.php';
+
+function mvlog_session_start(): void {
+    if (session_status() === PHP_SESSION_ACTIVE) return;
+    $secure = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off');
+    session_name('MVLOGSESSID');
+    session_set_cookie_params([
+        'lifetime' => 0,
+        'path' => '/mvlog',
+        'secure' => $secure,
+        'httponly' => true,
+        'samesite' => 'Lax',
+    ]);
+    session_start();
+}
+
+function mvlog_auth_config(): array {
+    if (!is_file(MVLOG_AUTH_CONFIG)) return ['users' => []];
+    $config = require MVLOG_AUTH_CONFIG;
+    return is_array($config) ? $config : ['users' => []];
+}
+
+function mvlog_login(string $user, string $password): bool {
+    mvlog_session_start();
+    $users = mvlog_auth_config()['users'] ?? [];
+    $hash = is_array($users) ? ($users[$user] ?? null) : null;
+    if (!is_string($hash) || !password_verify($password, $hash)) return false;
+    session_regenerate_id(true);
+    $_SESSION['mvlog_user'] = $user;
+    $_SESSION['mvlog_login_at'] = time();
+    return true;
+}
+
+function mvlog_current_user(): ?string {
+    mvlog_session_start();
+    return isset($_SESSION['mvlog_user']) && is_string($_SESSION['mvlog_user']) ? $_SESSION['mvlog_user'] : null;
+}
+
+function mvlog_require_login(): void {
+    if (mvlog_current_user() !== null) return;
+    $next = $_SERVER['REQUEST_URI'] ?? '/mvlog/new.php';
+    header('Location: login.php?next=' . rawurlencode($next));
+    exit;
+}
+
+function mvlog_logout(): void {
+    mvlog_session_start();
+    $_SESSION = [];
+    if (ini_get('session.use_cookies')) {
+        $params = session_get_cookie_params();
+        setcookie(session_name(), '', time() - 42000, $params['path'], $params['domain'] ?? '', $params['secure'], $params['httponly']);
+    }
+    session_destroy();
+}
+
+function mvlog_safe_next(string $next): string {
+    if ($next === '' || str_contains($next, "\n") || str_contains($next, "\r")) return 'new.php';
+    $parts = parse_url($next);
+    if ($parts === false || isset($parts['scheme']) || isset($parts['host'])) return 'new.php';
+    return $next;
+}