GUACAMOLE-325: Use select() if poll() is unavailable.

src/libguac/Makefile.am

@@ -68,7 +68,8 @@ noinst_HEADERS =      \
     encode-png.h      \
     palette.h         \
     user-handlers.h   \
-    raw_encoder.h
+    raw_encoder.h     \
+    wait-fd.h
 
 libguac_la_SOURCES =   \
     audio.c            \
@@ -92,7 +93,8 @@ libguac_la_SOURCES =   \
     unicode.c          \
     user.c             \
     user-handlers.c    \
-    user-handshake.c
+    user-handshake.c   \
+    wait-fd.c
 
 # Compile WebP support if available
 if ENABLE_WEBP

src/libguac/socket-fd.c

@@ -21,8 +21,8 @@
 
 #include "error.h"
 #include "socket.h"
+#include "wait-fd.h"
 
-#include <poll.h>
 #include <pthread.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -31,6 +31,10 @@
 #include <sys/time.h>
 #include <unistd.h>
 
+#ifdef __MINGW32__
+#include <winsock2.h>
+#endif
+
 /**
  * Data associated with an open socket which writes to a file descriptor.
  */
@@ -330,24 +334,9 @@ static ssize_t guac_socket_fd_write_handler(guac_socket* socket,
 static int guac_socket_fd_select_handler(guac_socket* socket,
         int usec_timeout) {
 
+    /* Wait for data on socket */
     guac_socket_fd_data* data = (guac_socket_fd_data*) socket->data;
-
-    int retval;
-
-    /* Initialize with single underlying file descriptor */
-    struct pollfd fds[1] = {{
-        .fd      = data->fd,
-        .events  = POLLIN,
-        .revents = 0,
-    }};
-
-    /* No timeout if usec_timeout is negative */
-    if (usec_timeout < 0)
-        retval = poll(fds, 1, -1);
-
-    /* Handle timeout if specified, rounding up to poll()'s granularity */
-    else
-        retval = poll(fds, 1, (usec_timeout + 999) / 1000);
+    int retval = guac_wait_for_fd(data->fd, usec_timeout);
 
     /* Properly set guac_error */
     if (retval <  0) {
@@ -355,7 +344,7 @@ static int guac_socket_fd_select_handler(guac_socket* socket,
         guac_error_message = "Error while waiting for data on socket";
     }
 
-    if (retval == 0) {
+    else if (retval == 0) {
         guac_error = GUAC_STATUS_TIMEOUT;
         guac_error_message = "Timeout while waiting for data on socket";
     }

src/libguac/socket-ssl.c

@@ -22,8 +22,8 @@
 #include "error.h"
 #include "socket-ssl.h"
 #include "socket.h"
+#include "wait-fd.h"
 
-#include <poll.h>
 #include <stdlib.h>
 
 #include <openssl/ssl.h>
@@ -69,23 +69,7 @@ static ssize_t __guac_socket_ssl_write_handler(guac_socket* socket,
 static int __guac_socket_ssl_select_handler(guac_socket* socket, int usec_timeout) {
 
     guac_socket_ssl_data* data = (guac_socket_ssl_data*) socket->data;
-
-    int retval;
-
-    /* Initialize with single underlying file descriptor */
-    struct pollfd fds[1] = {{
-        .fd      = data->fd,
-        .events  = POLLIN,
-        .revents = 0,
-    }};
-
-    /* No timeout if usec_timeout is negative */
-    if (usec_timeout < 0)
-        retval = poll(fds, 1, -1);
-
-    /* Handle timeout if specified, rounding up to poll()'s granularity */
-    else
-        retval = poll(fds, 1, (usec_timeout + 999) / 1000);
+    int retval = guac_wait_for_fd(data->fd, usec_timeout);
 
     /* Properly set guac_error */
     if (retval <  0) {

src/libguac/wait-fd.c

@@ -0,0 +1,72 @@
+/*
+ * 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 "config.h"
+
+#ifdef __MINGW32__
+#    include <winsock2.h>
+#else
+#    ifdef HAVE_POLL
+#        include <poll.h>
+#    else
+#        include <sys/select.h>
+#    endif
+#endif
+
+#ifdef HAVE_POLL
+int guac_wait_for_fd(int fd, int usec_timeout) {
+
+    /* Initialize with single underlying file descriptor */
+    struct pollfd fds[1] = {{
+        .fd      = fd,
+        .events  = POLLIN,
+        .revents = 0
+    }};
+
+    /* No timeout if usec_timeout is negative */
+    if (usec_timeout < 0)
+        return poll(fds, 1, -1);
+
+    /* Handle timeout if specified, rounding up to poll()'s granularity */
+    return poll(fds, 1, (usec_timeout + 999) / 1000);
+
+}
+#else
+int guac_wait_for_fd(int fd, int usec_timeout) {
+
+    fd_set fds;
+
+    /* Initialize fd_set with single underlying file descriptor */
+    FD_ZERO(&fds);
+    FD_SET(fd, &fds);
+
+    /* No timeout if usec_timeout is negative */
+    if (usec_timeout < 0)
+        return select(fd + 1, &fds, NULL, NULL, NULL); 
+
+    /* Handle timeout if specified */
+    struct timeval timeout = {
+        .tv_sec  = usec_timeout / 1000000,
+        .tv_usec = usec_timeout % 1000000
+    };
+
+    return select(fd + 1, &fds, NULL, NULL, &timeout);
+
+}
+#endif

src/libguac/wait-fd.h

@@ -0,0 +1,41 @@
+/*
+ * 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.
+ */
+
+#ifndef GUAC_WAIT_FD_H
+#define GUAC_WAIT_FD_H
+
+/**
+ * Waits for data to be available for reading on a given file descriptor,
+ * similar to the POSIX select() and poll() functions.
+ *
+ * @param fd
+ *     The file descriptor to wait for.
+ *
+ * @param usec_timeout
+ *     The maximum number of microseconds to wait for data, or -1 to
+ *     potentially wait forever.
+ *
+ * @return
+ *     Positive if data is available for reading, zero if the timeout elapsed
+ *     and no data is available, negative if an error occurs, in which case
+ *     errno will also be set.
+ */
+int guac_wait_for_fd(int fd, int usec_timeout);
+
+#endif