$re = '/<([^>]*)>([^<]*)<\/\1>/m';
$str = 'Apr 22 19:54:29 138.126.78.80 <STONEGATE_LOG><TIMESTAMP>2019-04-22 15:54:28</TIMESTAMP><LOGID>9999999</LOGID><NODEID>1.2.3.4</NODEID><FACILITY>Packet Filtering</FACILITY><TYPE>Notification</TYPE><EVENT>New connection</EVENT><ACTION>Allow</ACTION><SRC>4.5.6.7</SRC><DST>X.X.X.X</DST><SERVICE>HTTP</SERVICE><PROTOCOL>2</PROTOCOL><SPORT>12345</SPORT><DPORT>99</DPORT><RULEID>60732.1</RULEID><SRCIF>5</SRCIF><COMPID>some text here</COMPID><RECEPTIONTIME>2019-04-22 15:54:29</RECEPTIONTIME><SENDERTYPE>Firewall</SENDERTYPE><SITUATION>Connection_Allowed</SITUATION><EVENTID>99999999999</EVENTID></STONEGATE_LOG>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php