usock: add helper waiting for socket to be ready

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

diff --git a/usock.c b/usock.c
index 64eab9e..db1ddce 100644 (file)
--- a/usock.c
+++ b/usock.c
@@ -20,6 +20,7 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <netdb.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <netdb.h>

+#include <poll.h>

 #include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>


@@ -130,3 +131,29 @@ int usock(int type, const char *host, const char *service) {
        usock_set_flags(sock, type);
        return sock;
 }
        usock_set_flags(sock, type);
        return sock;
 }

+
+int usock_wait_ready(int fd, int msecs) {
+       struct pollfd fds[1];
+       int res;
+
+       fds[0].fd = fd;
+       fds[0].events = POLLOUT;
+
+       res = poll(fds, 1, msecs);
+       if (res < 0) {
+               return errno;
+       } else if (res == 0) {
+               return -ETIMEDOUT;
+       } else {
+               int err = 0;
+               socklen_t optlen = sizeof(err);
+
+               res = getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &optlen);
+               if (res)
+                       return errno;
+               if (err)
+                       return err;
+       }
+
+       return 0;
+}

diff --git a/usock.h b/usock.h
index 8345581..b0b952b 100644 (file)
--- a/usock.h
+++ b/usock.h
@@ -33,4 +33,15 @@
 const char *usock_port(int port);
 int usock(int type, const char *host, const char *service);
 
 const char *usock_port(int port);
 int usock(int type, const char *host, const char *service);
 

+/**
+ * Wait for a socket to become ready.
+ *
+ * This may be useful for users of USOCK_NONBLOCK to wait (with a timeout)
+ * for a socket.
+ *
+ * @param fd file descriptor of socket
+ * @param msecs timeout in microseconds
+ */
+int usock_wait_ready(int fd, int msecs);
+

 #endif /* USOCK_H_ */
 #endif /* USOCK_H_ */