poll: Fixed the usage of WSAPoll() on Windows.

This should fix ticket #101.

libssh/poll.c

@@ -94,10 +94,10 @@ int ssh_poll(ssh_pollfd_t *fds, nfds_t nfds, int timeout) {
 
 #else /* HAVE_POLL */
 
-#include <sys/types.h>
-
 typedef int (*poll_fn)(ssh_pollfd_t *, nfds_t, int);
-static poll_fn win_poll;
+static poll_fn ssh_poll_emu;
+
+#include <sys/types.h>
 
 #ifdef _WIN32
 #ifndef STRICT
@@ -108,6 +108,25 @@ static poll_fn win_poll;
 #include <windows.h>
 #include <winsock2.h>
 
+#ifndef WSAPOLLFD
+typedef ssh_pollfd_t WSAPOLLFD;
+#endif
+
+typedef int (WSAAPI* WSAPoll_FunctionType)(WSAPOLLFD fdarray[],
+                                           ULONG nfds,
+                                           INT timeout
+);
+
+static WSAPoll_FunctionType wsa_poll;
+
+int win_poll(ssh_pollfd_t *fds, nfds_t nfds, int timeout) {
+    if (wsa_poll) {
+        return (wsa_poll)(fds, nfds, timeout);
+    }
+
+    return SOCKET_ERROR;
+}
+
 #define WS2_LIBRARY "ws2_32.dll"
 static HINSTANCE hlib;
 
@@ -243,24 +262,23 @@ static int bsd_poll(ssh_pollfd_t *fds, nfds_t nfds, int timeout) {
 }
 
 void ssh_poll_init(void) {
-    poll_fn wsa_poll = NULL;
-
 #ifdef _WIN32
     hlib = LoadLibrary(WS2_LIBRARY);
     if (hlib != NULL) {
-        wsa_poll = (poll_fn) GetProcAddress(hlib, "WSAPoll");
+        wsa_poll = (WSAPoll_FunctionType) (void *) GetProcAddress(hlib, "WSAPoll");
     }
 #endif /* _WIN32 */
 
     if (wsa_poll == NULL) {
-        win_poll = bsd_poll;
+        ssh_poll_emu = bsd_poll;
     } else {
-        win_poll = wsa_poll;
+        ssh_poll_emu = win_poll;
     }
 }
 
 void ssh_poll_cleanup(void) {
-    win_poll = bsd_poll;
+    ssh_poll_emu = bsd_poll;
+    wsa_poll = NULL;
 
     FreeLibrary(hlib);
 
@@ -268,7 +286,7 @@ void ssh_poll_cleanup(void) {
 }
 
 int ssh_poll(ssh_pollfd_t *fds, nfds_t nfds, int timeout) {
-    return win_poll(fds, nfds, timeout);
+    return (ssh_poll_emu)(fds, nfds, timeout);
 }
 
 #endif /* HAVE_POLL */