そこで、最初に PHP.net で Ron Korving の投稿を見つけ、それを修正して (無限ループ、無効な文字、書き込み不可の親ディレクトリから) 少し安全にし、もう少しエントロピーを使用するようにしました。
<?php
/**
* Creates a random unique temporary directory, with specified parameters,
* that does not already exist (like tempnam(), but for dirs).
*
* Created dir will begin with the specified prefix, followed by random
* numbers.
*
* @link https://php.net/manual/en/function.tempnam.php
*
* @param string|null $dir Base directory under which to create temp dir.
* If null, the default system temp dir (sys_get_temp_dir()) will be
* used.
* @param string $prefix String with which to prefix created dirs.
* @param int $mode Octal file permission mask for the newly-created dir.
* Should begin with a 0.
* @param int $maxAttempts Maximum attempts before giving up (to prevent
* endless loops).
* @return string|bool Full path to newly-created dir, or false on failure.
*/
function tempdir($dir = null, $prefix = 'tmp_', $mode = 0700, $maxAttempts = 1000)
{
/* Use the system temp dir by default. */
if (is_null($dir))
{
$dir = sys_get_temp_dir();
}
/* Trim trailing slashes from $dir. */
$dir = rtrim($dir, DIRECTORY_SEPARATOR);
/* If we don't have permission to create a directory, fail, otherwise we will
* be stuck in an endless loop.
*/
if (!is_dir($dir) || !is_writable($dir))
{
return false;
}
/* Make sure characters in prefix are safe. */
if (strpbrk($prefix, '\\/:*?"<>|') !== false)
{
return false;
}
/* Attempt to create a random directory until it works. Abort if we reach
* $maxAttempts. Something screwy could be happening with the filesystem
* and our loop could otherwise become endless.
*/
$attempts = 0;
do
{
$path = sprintf('%s%s%s%s', $dir, DIRECTORY_SEPARATOR, $prefix, mt_rand(100000, mt_getrandmax()));
} while (
!mkdir($path, $mode) &&
$attempts++ < $maxAttempts
);
return $path;
}
?>
それでは、試してみましょう:
<?php
echo "\n";
$dir1 = tempdir();
echo $dir1, "\n";
var_dump(is_dir($dir1), is_writable($dir1));
var_dump(rmdir($dir1));
echo "\n";
$dir2 = tempdir('/tmp', 'stack_');
echo $dir2, "\n";
var_dump(is_dir($dir2), is_writable($dir2));
var_dump(rmdir($dir2));
echo "\n";
$dir3 = tempdir(null, 'stack_');
echo $dir3, "\n";
var_dump(is_dir($dir3), is_writable($dir3));
var_dump(rmdir($dir3));
?>
結果:
/var/folders/v4/647wm24x2ysdjwx6z_f07_kw0000gp/T/tmp_900342820
bool(true)
bool(true)
bool(true)
/tmp/stack_1102047767
bool(true)
bool(true)
bool(true)
/var/folders/v4/647wm24x2ysdjwx6z_f07_kw0000gp/T/stack_638989419
bool(true)
bool(true)
bool(true)