SATS/lib/cyclic-hash/decr

#!/usr/bin/php

<?php
	
	require_once __DIR__.'/../include/const';


	/* [1] Function that generates a random secret
	=========================================================*/
	function generate_secret(){

		/* (1) Generate random set */
		$charlist = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_';

		/* (2) Set useful variables */
		$clen = strlen($charlist);
		$secret = '';

		/* (3) Generate random characters one by one */
		for( $i = 0 ; $i < SECRET_SIZE ; $i++ )
			$secret .= $charlist[rand(0, $clen - 1)];

		/* (4) Return the secret */
		return $secret;
	}


	/* [2] Fetch necessary data
	=========================================================*/
	/* (1) Fetch secret file */
	$secret = @file_get_contents(SECRET_CONF);
	
	/* (2) Check secret file format */
	if( !is_string($secret) || !preg_match("/^(.{250}):(\d+)$/", $secret, $match) ){

		// Generate new secret
		$secret = generate_secret().':1000';

		// Try to override the secret file
		@file_put_contents(SECRET_CONF, $secret) && die(0) || die(127);
	}

	/* (3) Extract data */
	$key   = (string) $match[1];
	$depth = (int)    $match[2];


	/* [3] If can decrement, decrement
	=========================================================*/
	if( $depth > 1 ){

		/* (1) Decrement the depth */
		$depth--;

		/* (2) Try to override the secret file */
		@file_put_contents(SECRET_CONF, "$key:$depth") && die(0) || die(127);


	/* [4] If cannot decrement, generate new password
	=========================================================*/
	}else{
		
		// Generate new secret
		$secret = generate_secret().':1000';

		// Try to override the secret file
		file_put_contents(SECRET_CONF, $secret) && die(0) || die(127);

	}


?>