Bug #78038 [Fbk]: Socket_Select fails when resource array contains non-sequential keys

Edit report at https://bugs.php.net/bug.php?id=78038&edit=1 ID: 78038 Updated by: nikic@php.net Reported by: ogdg at protonmail dot com Summary: Socket_Select fails when resource array contains non-sequential keys Status: Feedback Type: Bug Package: Sockets related Operating System: Fedora 30 PHP Version: 7.3.5 Block user comment: N Private report: N New Comment: One recent change comes to mind here: https://github.com/php/php-src/commit/bdac9ef10d90997f9576564dde693cbef6594142#diff-9df410db21c230cd2ec04a4c95ccd20f However, it is in stream_select(), not socket_select(). When you say "previous versions" do you mean 7.3.4 or some older version? Previous Comments: ------------------------------------------------------------------------ [2019-05-20 10:00:10] daverandom@php.net Thank you for this bug report. To properly diagnose the problem, we need a short but complete example script to be able to reproduce this bug ourselves. A proper reproducing script starts with <?php and ends with ?>, is max. 10-20 lines long and does not require any external resources such as databases, etc. If the script requires a database to demonstrate the issue, please make sure it creates all necessary tables, stored procedures etc. Please avoid embedding huge scripts into the report. I cannot reproduce this in 7.3.5 or any other version. Additionally, none of the relevant code in php-src has been changed for several years in 7.3[1] or master[2]. Please recheck your code, var_dump($r) and verify that it contains at least one valid socket resource, and if so please provide a complete reproducing script. There is a lot of code in the wild which utilises a pattern roughly like below - it's likely that if it were broken then a lot of people would be shouting about it :-) $socket = socket_create(/* stuff */); // ...set up the socket $sockets[(int)$socket] = $socket; // Add socket to array indexed by resource ID $w = $e = NULL; $r = $sockets; $check = socket_select($r, $w, $e, 0); [1] https://github.com/php/php-src/blame/PHP-7.3/ext/sockets/sockets.c#L915-L977 [2] https://github.com/php/php-src/blame/master/ext/sockets/sockets.c#L921-L983 ------------------------------------------------------------------------ [2019-05-20 09:27:50] ogdg at protonmail dot com Description: ------------ This bug occurs in PHP CLI 7.3.5! When socket connection resources are indexed in an array by non-sequential numeric keys, socket_select throws a warning and does not actually accept the array even though it contains valid socket resources. By manually re-indexing the array to contain sequentially numbered keys, the problem disappears. This could a problem with large key values, or non sequential keys, or both. The problem did not exist in previous versions of PHP, and it is not valid for socket_select to require arrays that are sequentially numbered, as there are reasons to index connection arrays by process ID or some other meaningful number. Test script: --------------- # Assume each $connN variable is a valid socket resource # Note that array keys are INT and not string type $connections = array(1235 => $conn1, 2084 => $conn2, 3509 => $conn3); $w = $e = NULL; $r = $connections; $check = socket_select($r, $w, $e, 0); # The ABOVE code fails with bogus warnings in PHP 7.3.5 # The BELOW code works $w = $e = NULL; foreach($connections as $v) $r[] = $v; $check = socket_select($r, $w, $e, 0); Expected result: ---------------- Expect socket_select to work as intended and return a value for $check and a modified connection resource array if appropriate. Actual result: -------------- Result is two warnings: socket_select(): supplied argument is not a valid Socket resource socket_select(): no resource arrays were passed to select Previous versions of PHP, including PHP 7 did not have this problem. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=78038&edit=1