1 files changed, 74 insertions, 0 deletions
diff --git a/network_io/unix/socket_util.c b/network_io/unix/socket_util.c
new file mode 100644
index 000000000000..6cd28a55c432
--- /dev/null
+++ b/network_io/unix/socket_util.c
@@ -0,0 +1,74 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr_network_io.h"
+#include "apr_poll.h"
+
+APR_DECLARE(apr_status_t) apr_socket_atreadeof(apr_socket_t *sock, int *atreadeof)
+{
+    apr_pollfd_t pfds[1];
+    apr_status_t rv;
+    apr_int32_t  nfds;
+
+    /* The purpose here is to return APR_SUCCESS only in cases in
+     * which it can be unambiguously determined whether or not the
+     * socket will return EOF on next read.  In case of an unexpected
+     * error, return that. */
+
+    pfds[0].reqevents = APR_POLLIN;
+    pfds[0].desc_type = APR_POLL_SOCKET;
+    pfds[0].desc.s = sock;
+
+    do {
+        rv = apr_poll(&pfds[0], 1, &nfds, 0);
+    } while (APR_STATUS_IS_EINTR(rv));
+
+    if (APR_STATUS_IS_TIMEUP(rv)) {
+        /* Read buffer empty -> subsequent reads would block, so,
+         * definitely not at EOF. */
+        *atreadeof = 0;
+        return APR_SUCCESS;
+    }
+    else if (rv) {
+        /* Some other error -> unexpected error. */
+        return rv;
+    }
+    else if (nfds == 1 && pfds[0].rtnevents == APR_POLLIN) {
+        apr_sockaddr_t unused;
+        apr_size_t len = 1;
+        char buf;
+
+        /* The socket is readable - peek to see whether it returns EOF
+         * without consuming bytes from the socket buffer. */
+        rv = apr_socket_recvfrom(&unused, sock, MSG_PEEK, &buf, &len);
+        if (rv == APR_EOF) {
+            *atreadeof = 1;
+            return APR_SUCCESS;
+        }
+        else if (rv) {
+            /* Read error -> unexpected error. */
+            return rv;
+        }
+        else {
+            *atreadeof = 0;
+            return APR_SUCCESS;
+        }
+    }
+
+    /* Should not fall through here. */
+    return APR_EGENERAL;
+}
+