watcher: Add Windows support

Instead of a pipe we use a TCP socketpair (can't select() a _pipe()), and
Windsock2 send/recv functions instead of read/write.

Currently supported (and required) are file descriptors provided by Winsock
only; we might use a separate mechanism for traditional file handles if
required (or switch to Windows events and WaitForMultipleObjects) for a future
version.

src/libstrongswan/processing/watcher.c

@@ -24,7 +24,9 @@
 
 #include <unistd.h>
 #include <errno.h>
+#ifndef WIN32
 #include <sys/select.h>
+#endif
 #include <fcntl.h>
 
 typedef struct private_watcher_t private_watcher_t;
@@ -119,7 +121,14 @@ static void update(private_watcher_t *this)
 	this->pending = TRUE;
 	if (this->notify[1] != -1)
 	{
-		ignore_result(write(this->notify[1], buf, sizeof(buf)));
+#ifdef WIN32
+		if (send(this->notify[1], buf, sizeof(buf), 0) == -1)
+#else
+		if (write(this->notify[1], buf, sizeof(buf)) == -1)
+#endif
+		{
+			DBG1(DBG_JOB, "notifying watcher failed: %s", strerror(errno));
+		}
 	}
 }
 
@@ -293,21 +302,40 @@ static job_requeue_t watch(private_watcher_t *this)
 	{
 		char buf[1];
 		bool old;
+		ssize_t len;
 		job_t *job;
 
 		DBG2(DBG_JOB, "watcher going to select()");
 		thread_cleanup_push((void*)activate_all, this);
 		old = thread_cancelability(TRUE);
+
 		res = select(maxfd + 1, &rd, &wr, &ex, NULL);
 		thread_cancelability(old);
 		thread_cleanup_pop(FALSE);
+
 		if (res > 0)
 		{
 			if (this->notify[0] != -1 && FD_ISSET(this->notify[0], &rd))
 			{
-				DBG2(DBG_JOB, "watcher got notification, rebuilding");
+				while (TRUE)
-				while (read(this->notify[0], buf, sizeof(buf)) > 0);
+				{
+#ifdef WIN32
+					len = recv(this->notify[0], buf, sizeof(buf), 0);
+#else
+					len = read(this->notify[0], buf, sizeof(buf));
+#endif
+					if (len == -1)
+					{
+						if (errno != EAGAIN && errno != EWOULDBLOCK)
+						{
+							DBG1(DBG_JOB, "reading watcher notify failed: %s",
+								 strerror(errno));
+						}
+						break;
+					}
+				}
 				this->pending = FALSE;
+				DBG2(DBG_JOB, "watcher got notification, rebuilding");
 				return JOB_REQUEUE_DIRECT;
 			}
 
@@ -446,13 +474,60 @@ METHOD(watcher_t, destroy, void,
 	free(this);
 }
 
+#ifdef WIN32
+
+/**
+ * Create notify pipe with a TCP socketpair
+ */
+static bool create_notify(private_watcher_t *this)
+{
+	u_long on = 1;
+
+	if (socketpair(AF_INET, SOCK_STREAM, 0, this->notify) == 0)
+	{
+		/* use non-blocking I/O on read-end of notify pipe */
+		if (ioctlsocket(this->notify[0], FIONBIO, &on) == 0)
+		{
+			return TRUE;
+		}
+		DBG1(DBG_LIB, "setting watcher notify pipe read-end non-blocking "
+			 "failed: %s", strerror(errno));
+	}
+	return FALSE;
+}
+
+#else /* !WIN32 */
+
+/**
+ * Create a notify pipe with a one-directional pipe
+ */
+static bool create_notify(private_watcher_t *this)
+{
+	int flags;
+
+	if (pipe(this->notify) == 0)
+	{
+		/* use non-blocking I/O on read-end of notify pipe */
+		flags = fcntl(this->notify[0], F_GETFL);
+		if (flags != -1 &&
+			fcntl(this->notify[0], F_SETFL, flags | O_NONBLOCK) != -1)
+		{
+			return TRUE;
+		}
+		DBG1(DBG_LIB, "setting watcher notify pipe read-end non-blocking "
+			 "failed: %s", strerror(errno));
+	}
+	return FALSE;
+}
+
+#endif /* !WIN32 */
+
 /**
  * See header
  */
 watcher_t *watcher_create()
 {
 	private_watcher_t *this;
-	int flags;
 
 	INIT(this,
 		.public = {
@@ -467,18 +542,7 @@ watcher_t *watcher_create()
 		.notify = {-1, -1},
 	);
 
-	if (pipe(this->notify) == 0)
+	if (!create_notify(this))
-	{
-		/* use non-blocking I/O on read-end of notify pipe */
-		flags = fcntl(this->notify[0], F_GETFL);
-		if (flags == -1 ||
-			fcntl(this->notify[0], F_SETFL, flags | O_NONBLOCK) == -1)
-		{
-			DBG1(DBG_LIB, "setting watcher notify pipe read-end non-blocking "
-				 "failed: %s", strerror(errno));
-		}
-	}
-	else
 	{
 		DBG1(DBG_LIB, "creating watcher notify pipe failed: %s",
 			 strerror(errno));