add writev_retry to avoid incomplete writes

diff --git a/libubus.c b/libubus.c
index 1ebc4214403e705d0f5c3d8d2476e2c3eb023836..5b97e455bfca29091077151ebe96d4625653b842 100644 (file)
--- a/libubus.c
+++ b/libubus.c
@@ -1,6 +1,7 @@
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <sys/socket.h>
+#include <fcntl.h>
 #include <unistd.h>
 
 #include <libubox/blob.h>
@@ -71,6 +72,38 @@ out:
        return err;
 }
 
+static int writev_retry(int fd, struct iovec *iov, int iov_len)
+{
+       int len = 0;
+
+       do {
+               int cur_len = writev(fd, iov, iov_len);
+               if (cur_len < 0) {
+                       switch(errno) {
+                       case EAGAIN:
+                               /* turn off non-blocking mode */
+                               fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) &
+                                     ~O_NONBLOCK);
+                               break;
+                       case EINTR:
+                               break;
+                       default:
+                               return -1;
+                       }
+                       continue;
+               }
+               len += cur_len;
+               while (cur_len >= iov->iov_len) {
+                       cur_len -= iov->iov_len;
+                       iov_len--;
+                       iov++;
+                       if (!cur_len || !iov_len)
+                               return len;
+               }
+               iov->iov_len -= cur_len;
+       } while (1);
+}
+
 static int ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
                         struct blob_attr *msg, int cmd, uint32_t peer)
 {
@@ -92,7 +125,7 @@ static int ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
        iov[1].iov_base = (char *) msg;
        iov[1].iov_len = blob_raw_len(msg);
 
-       return writev(ctx->sock.fd, iov, 2);
+       return writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov));
 }
 
 static int ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,