Fix phpGH-20240: FTP with SSL: ftp_fput(): Connection timed out on successful writes

Looking at the strace, the timeout is only 1s which may be too low
anyway for checking for a response, but some servers also don't end up
replying finally anyway and close the connection already.

`data_available` was originally used for non-blocking downloads/uploads
and then reused for the shutdown sequence, but its error handling was
never adjusted to be silent.

Closes phpGH-20294.

Author: ndossche

NEWS

@@ -21,6 +21,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-19974 (fpm_status_export_to_zval segfault for parallel
     execution). (Jakub Zelenka, txuna)
 
+- FTP:
+  . Fixed bug GH-20240 (FTP with SSL: ftp_fput(): Connection timed out on
+    successful writes). (nielsdos)
+
 - GD:
   . Fixed bug GH-20070 (Return type violation in imagefilter when an invalid
     filter is provided). (Girgias)

ext/ftp/ftp.c

@@ -1605,14 +1605,17 @@ my_recv(ftpbuf_t *ftp, php_socket_t s, void *buf, size_t len)
 
 /* {{{ data_available */
 int
-data_available(ftpbuf_t *ftp, php_socket_t s)
+data_available(ftpbuf_t *ftp, php_socket_t s, bool silent)
 {
 	int		n;
 
 	n = my_poll(s, PHP_POLLREADABLE, 1000);
 	if (n < 1) {
 		char buf[256];
 		if (n == 0) {
+			if (silent) {
+				return 0;
+			}
 #ifdef PHP_WIN32
 			_set_errno(ETIMEDOUT);
 #else
@@ -1938,7 +1941,9 @@ static void ftp_ssl_shutdown(ftpbuf_t *ftp, php_socket_t fd, SSL *ssl_handle) {
 		done = 0;
 	}
 
-	while (!done && data_available(ftp, fd)) {
+	/* Don't report timeouts on the control channel if we're negotiating a shutdown already.
+	 * Some servers don't put a final response. */
+	while (!done && data_available(ftp, fd, true)) {
 		ERR_clear_error();
 		nread = SSL_read(ssl_handle, buf, sizeof(buf));
 		if (nread <= 0) {
@@ -2198,7 +2203,7 @@ ftp_nb_continue_read(ftpbuf_t *ftp)
 	data = ftp->data;
 
 	/* check if there is already more data */
-	if (!data_available(ftp, data->fd)) {
+	if (!data_available(ftp, data->fd, false)) {
 		return PHP_FTP_MOREDATA;
 	}