From a63fadd5034a8300ecd0573f4e1fe4c07c383064 Mon Sep 17 00:00:00 2001
From: Peter Knut <peter@pematon.com>
Date: Mon, 7 Oct 2024 22:20:32 +0200
Subject: [PATCH] Refactor working with a locked file

---
 adminer/include/auth.inc.php      |  8 ++---
 adminer/include/bootstrap.inc.php |  6 ++--
 adminer/include/functions.inc.php | 57 ++++++++++++++++++-------------
 3 files changed, 40 insertions(+), 31 deletions(-)

diff --git a/adminer/include/auth.inc.php b/adminer/include/auth.inc.php
index 099843bc..603bd470 100644
--- a/adminer/include/auth.inc.php
+++ b/adminer/include/auth.inc.php
@@ -82,11 +82,11 @@ function build_http_url($server, $username, $password, $defaultServer, $defaultP
 
 function add_invalid_login() {
 	global $adminer;
-	$fp = file_open_lock(get_temp_dir() . "/adminer.invalid");
-	if (!$fp) {
+	$file = open_file_with_lock(get_temp_dir() . "/adminer.invalid");
+	if (!$file) {
 		return;
 	}
-	$invalids = unserialize(stream_get_contents($fp));
+	$invalids = unserialize(stream_get_contents($file));
 	$time = time();
 	if ($invalids) {
 		foreach ($invalids as $ip => $val) {
@@ -100,7 +100,7 @@ function add_invalid_login() {
 		$invalid = array($time + 30*60, 0); // active for 30 minutes
 	}
 	$invalid[1]++;
-	file_write_unlock($fp, serialize($invalids));
+	write_and_unlock_file($file, serialize($invalids));
 }
 
 function check_invalid_login() {
diff --git a/adminer/include/bootstrap.inc.php b/adminer/include/bootstrap.inc.php
index 6951da57..b884ee33 100644
--- a/adminer/include/bootstrap.inc.php
+++ b/adminer/include/bootstrap.inc.php
@@ -32,9 +32,9 @@ if (isset($_GET["file"])) {
 }
 
 if ($_GET["script"] == "version") {
-	$fp = file_open_lock(get_temp_dir() . "/adminer.version");
-	if ($fp) {
-		file_write_unlock($fp, serialize(array("signature" => $_POST["signature"], "version" => $_POST["version"])));
+	$file = open_file_with_lock(get_temp_dir() . "/adminer.version");
+	if ($file) {
+		write_and_unlock_file($file, serialize(["signature" => $_POST["signature"], "version" => $_POST["version"]]));
 	}
 	exit;
 }
diff --git a/adminer/include/functions.inc.php b/adminer/include/functions.inc.php
index be585333..67e5e583 100644
--- a/adminer/include/functions.inc.php
+++ b/adminer/include/functions.inc.php
@@ -1215,33 +1215,42 @@ function get_temp_dir() {
 	return $return;
 }
 
-/** Open and exclusively lock a file
-* @param string
-* @return resource or null for error
-*/
-function file_open_lock($filename) {
-	$fp = @fopen($filename, "r+"); // @ - may not exist
-	if (!$fp) { // c+ is available since PHP 5.2.6
-		$fp = @fopen($filename, "w"); // @ - may not be writable
-		if (!$fp) {
-			return;
-		}
-		chmod($filename, 0660);
+/**
+ * Opens and exclusively lock a file.
+ *
+ * @param string $filename
+ * @return resource|null
+ */
+function open_file_with_lock($filename)
+{
+	$file = fopen($filename, "c+");
+	if (!$file) {
+		return null;
 	}
-	flock($fp, LOCK_EX);
-	return $fp;
+
+	chmod($filename, 0660);
+
+	if (!flock($file, LOCK_EX)) {
+		fclose($file);
+		return null;
+	}
+
+	return $file;
 }
 
-/** Write and unlock a file
-* @param resource
-* @param string
-*/
-function file_write_unlock($fp, $data) {
-	rewind($fp);
-	fwrite($fp, $data);
-	ftruncate($fp, strlen($data));
-	flock($fp, LOCK_UN);
-	fclose($fp);
+/**
+ * Writes and unlocks a file.
+ *
+ * @param resource $file
+ * @param string $data
+ */
+function write_and_unlock_file($file, $data)
+{
+	rewind($file);
+	fwrite($file, $data);
+	ftruncate($file, strlen($data));
+	flock($file, LOCK_UN);
+	fclose($file);
 }
 
 /**