From: polone at townnews dot com Operating system: Any PHP version: 4.3.3 PHP Bug Type: *PDF functions Bug description: _php_stream_write() gets stuck in infinite loop on any error to send()
Description: ------------ (Please note, this looks like a similiar bug as #22753, but it is not - it's in a function layer much more abstract than the main/network.c bug, this one is in main/streams.c) A problem that occurs quite often with PHP scripts when remote hosts disconnect applications in PHP using the streams API is infinite looping with SIGPIPE. It appears an early attempt to remedy the situation was to ignore SIGPIPE, but this is not where the problem is. After reviewing the _php_stream_write() code and testing the loop in an error condition of -1, it became obvious why the looping occurs. The while() loop will never exit if an error occurs in the underlying send() call. This is because it returns a negative value (-1), but the type assigned in _php_stream_write() is size_t for the variable justwrote. For reference, "size_t" IS AN UNSIGNED INT, which means the condition: if (justwrote > 0) { // Buffering code } else { break; } will never execute the "else" condition. To fix this, change the following: size_t didwrite = 0, towrite; int justwrote; This bug has been present (as far as I can tell) since PHP 4.3.0. In addition, another change I've made is too main/network.c, in the php_sockop_write() function. Instead of ignoring SIGPIPE as the default handler, it would be better to set: didwrite = send(sock->socket, buf, count, MSG_NOSIGNAL); This will still work correctly when SIGPIPE would have been issued as EPIPE is still returned. Reproduce code: --------------- <?php $fp = fsockopen ("localhost", 80); while(fwrite($fp, "GET /doesntmatter HTTP/1.0\n\n")) { sleep(1); } ?> Expected result: ---------------- To end eventually. Instead, the script will eventually issue a SIGPIPE and create an infinite loop. Actual result: -------------- It never ends. -- Edit bug report at http://bugs.php.net/?id=25316&edit=1 -- Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=25316&r=trysnapshot4 Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=25316&r=trysnapshot5 Fixed in CVS: http://bugs.php.net/fix.php?id=25316&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=25316&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=25316&r=needtrace Try newer version: http://bugs.php.net/fix.php?id=25316&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=25316&r=support Expected behavior: http://bugs.php.net/fix.php?id=25316&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=25316&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=25316&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=25316&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=25316&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=25316&r=dst IIS Stability: http://bugs.php.net/fix.php?id=25316&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=25316&r=gnused