posix_getpwuid - PHP code example

How to Use the PHP Function posix_getpwuid()

Using the PHP POSIX library, developers can access a number of powerful functions for controlling the behavior of processes and for handling signals. One such function is posix_getpwuid(), which provides information about the user ID associated with the process. This article will discuss how to use this function as well as other functions that retrieve the user and group IDs of a process.

The posix_getpwuid() function retrieves the user ID of the current process using the lookup method. Like posix_geteuid(), it does not take any parameters and returns an integer value. The associative array returned by the function contains various elements of information related to the user ID, including the username (which is a short handle less than 16 characters), the password (provided it's not a shadow password) and more.

This is a useful function for determining whether a process is running as the system user, which can be particularly helpful when attempting to determine whether or not a web application has been compromised by an attacker. Using this function and other POSIX functions, developers can retrieve the effective and real user and group IDs of the current process and change them as needed.

RunCloud takes security seriously and disables a number of native PHP functions by default for our customers. This includes the posix_getpwuid function, as well as a variety of other functions such as getmyuid, fileowner, stat and parse_ini_file. To enable these functions, navigate to your Site Settings and change the disable_functions value to no.

posix_getpwuid example

public function owner( $file ) {
        $owneruid = @fileowner( $file );

        if ( ! $owneruid ) {
            return false;
        }

        if ( ! function_exists( 'posix_getpwuid' ) ) {
            return $owneruid;
        }

        $ownerarray = posix_getpwuid( $owneruid );

        if ( ! $ownerarray ) {
            return false;
        }

        return $ownerarray['name'];
    }

    /** * Gets the permissions of the specified file or filepath in their octal format. * * FIXME does not handle errors in fileperms() * * @since 2.5.0 * * @param string $file Path to the file. * @return string Mode of the file (the last 3 digits). */

public function owner( $file ) {
        $owneruid = @fileowner( $this->sftp_path( $file ) );

        if ( ! $owneruid ) {
            return false;
        }

        if ( ! function_exists( 'posix_getpwuid' ) ) {
            return $owneruid;
        }

        $ownerarray = posix_getpwuid( $owneruid );

        if ( ! $ownerarray ) {
            return false;
        }

        return $ownerarray['name'];
    }

    /** * Gets the permissions of the specified file or filepath in their octal format. * * @since 2.7.0 * * @param string $file Path to the file. * @return string Mode of the file (the last 3 digits). */

$v_typeflag = '0';
            clearstatcache();
            $v_size = sprintf("%011s", DecOct($v_info['size']));
        }

        $v_magic = 'ustar ';
        $v_version = ' ';
        $v_uname = '';
        $v_gname = '';

        if (function_exists('posix_getpwuid')) {
            $userinfo = posix_getpwuid($v_info[4]);
            $groupinfo = posix_getgrgid($v_info[5]);

            if (isset($userinfo['name'])) {
                $v_uname = $userinfo['name'];
            }

            if (isset($groupinfo['name'])) {
                $v_gname = $groupinfo['name'];
            }
        }

$this->markAsSkippedIfPosixIsMissing();

        $infos = stat($filepath);

        return $infos['uid'];
    }

    protected function getFileOwner($filepath)
    {
        $this->markAsSkippedIfPosixIsMissing();

        return ($datas = posix_getpwuid($this->getFileOwnerId($filepath))) ? $datas['name'] : null;
    }

    protected function getFileGroupId($filepath)
    {
        $this->markAsSkippedIfPosixIsMissing();

        $infos = stat($filepath);

        return $infos['gid'];
    }