1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "apr_network_io.h"
18 #include "apr_poll.h"
19
apr_socket_atreadeof(apr_socket_t * sock,int * atreadeof)20 APR_DECLARE(apr_status_t) apr_socket_atreadeof(apr_socket_t *sock, int *atreadeof)
21 {
22 apr_pollfd_t pfds[1];
23 apr_status_t rv;
24 apr_int32_t nfds;
25
26 /* The purpose here is to return APR_SUCCESS only in cases in
27 * which it can be unambiguously determined whether or not the
28 * socket will return EOF on next read. In case of an unexpected
29 * error, return that. */
30
31 pfds[0].reqevents = APR_POLLIN;
32 pfds[0].desc_type = APR_POLL_SOCKET;
33 pfds[0].desc.s = sock;
34
35 do {
36 rv = apr_poll(&pfds[0], 1, &nfds, 0);
37 } while (APR_STATUS_IS_EINTR(rv));
38
39 if (APR_STATUS_IS_TIMEUP(rv)) {
40 /* Read buffer empty -> subsequent reads would block, so,
41 * definitely not at EOF. */
42 *atreadeof = 0;
43 return APR_SUCCESS;
44 }
45 else if (rv) {
46 /* Some other error -> unexpected error. */
47 return rv;
48 }
49 /* Many platforms return only APR_POLLIN; OS X returns APR_POLLHUP|APR_POLLIN */
50 else if (nfds == 1 && (pfds[0].rtnevents & APR_POLLIN) == APR_POLLIN) {
51 apr_sockaddr_t unused;
52 apr_size_t len = 1;
53 char buf;
54
55 /* The socket is readable - peek to see whether it returns EOF
56 * without consuming bytes from the socket buffer. */
57 rv = apr_socket_recvfrom(&unused, sock, MSG_PEEK, &buf, &len);
58 if (rv == APR_EOF) {
59 *atreadeof = 1;
60 return APR_SUCCESS;
61 }
62 else if (rv) {
63 /* Read error -> unexpected error. */
64 return rv;
65 }
66 else {
67 *atreadeof = 0;
68 return APR_SUCCESS;
69 }
70 }
71
72 /* Should not fall through here. */
73 return APR_EGENERAL;
74 }
75
76