Single quotes, double quotes and passwords containing $ in Windows and Unix - windows

Question

I'm writing a PHP script to automate a mysqldump command. The method I've selected is using exec( $exec_string . ' 2>&1' ). This script must work on Windows and *nix platforms.
Sadly, some passwords contain the dreaded $ symbol, and so the `-p'passwordcontaining$' must be quoted.
Here are the challenges I've noted so far:
On *nix, you must use the single quote, otherwise it will expand the
$ as a variable.
On Windows, you must use the double quote, because single quotes are treated literally
Escaping the $ is not an option, because on Windows the backslash is only interpreted as the escape character when preceding the double quote (\"), so \$ would be interpreted literally
I don't know how to reliably detect OS to be able to "interactively" switch between single and double quotes.
Is there a trick I am missing that will work cross-platform?

Answer 1

You can dump from within a pdo PHP script :
<?php
$dumpSettings = array(
'include-tables' => array('table1', 'table2'),
'exclude-tables' => array('table3', 'table4'),
'compress' => CompressMethod::GZIP, /* CompressMethod::[GZIP, BZIP2, NONE] */
'no-data' => false, /* http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_no-data */
'add-drop-table' => false, /* http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_add-drop-table */
'single-transaction' => true, /* http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_single-transaction */
'lock-tables' => false, /* http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_lock-tables */
'add-locks' => true, /* http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_add-locks */
'extended-insert' => true /* http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_extended-insert */
);
$dump = new MySQLDump('database','database_user','database_pass','localhost', $dumpSettings);
$dump->start('forum_dump.sql.gz');
See https://github.com/clouddueling/mysqldump-php

Answer 2

Not crazy about the approach I ended up adopting (MySQLDump class seems to be a more robust approach than exec() ), but here it is in case it helps anyone.
Even though I didn't want to do OS detection, at first blush it doesn't seem that I can resolve the issues in quote interpretation. Happily, OS detection is relatively easy, if you're prepared to make some assumptions, such as "if it ain't running on Windows, then it's on some kind of *nix server".
Here's my basic approach, which I'm sure will get flamed.
// Inside class
protected $os_quote_char = "'"; // Unix default quote character
// Inside constructor
// Detect OS and set quote character appropriately
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN')
$this->os_quote_char = '"';
// Method for adding quotes
/**
* Adds the OS non-interpreted quote character to the string(s), provided each string doesn't already start with said quote character.
*
* The quote character is set in the constructor, based on detecting Windows OSes vs. any other (assumed to be *nix).
* You can pass in an array, in which case you will get an array of quoted strings in return.
*
* #param string|array $string_or_array
* #return string|array
*/
protected function os_quote( $string_or_array ){
$quoted_strings = array();
$string_array = (array) $string_or_array;
foreach ( $string_array as $string_to_quote ){
// don't quote already quoted strings
if ( substr( $string_to_quote, 0, 1 ) == $this->os_quote_char )
$quoted_strings[] = $string_to_quote;
else
$quoted_strings[] = $this->os_quote_char . $string_to_quote . $this->os_quote_char;
}
if ( is_array( $string_or_array ) )
return $quoted_strings;
else
return $quoted_strings[0];
}
// Actual usage example:
if ( function_exists( 'exec' ) ){
list( $user, $pwd, $host, $db, $file ) = $this->os_quote( array( DB_USER, DB_PASSWORD, DB_HOST, DB_NAME, $backup_file.'.sql' ) );
$exec = $this->get_executable_path() . 'mysqldump -u' . $user . ' -p' . $pwd . ' -h' . $host . ' --result-file=' . $file . ' ' . $db . ' 2>&1';
exec ( $exec, $output, $return );
}

Answer 3

It's hard to guess, what limitations you are talking about, but I suspect some of them are false
passthru('mysqldump -uddd -p"pass\'word$" ddd');
Worked for me under Windows and FreeBSD, as well as the command itself in the respective shells