winbind: fix smbd hanging on Solaris when winbindd closes socket.

On some versions of Solaris, we observed a strange effect of close(2)
on a socket: After the server (here winbindd) called close, the client fd
was not marked as readable for select. And a write call to the fd did
not produce an error EPIPE but just returned as if successful.

So while winbindd had called remove_client(), the corresponding smbd
still thought that it was connected, but failed to retrieve answers
for its queries.

This patch works around the problem by forcing the client fd to
the readable state: Just write one byte into the socket before
closing.

Michael
(cherry picked from commit 4528d0b5b32ab4cbbc2d5b09cd0d49062120e50b)

diff --git a/source/winbindd/winbindd.c b/source/winbindd/winbindd.c
index 44b5415726a70c1ce887057d8c1c40ae1d65a575..4af711ca8e79cef3a04ffd4c2c930d0fcb74a655 100644 (file)
--- a/source/winbindd/winbindd.c
+++ b/source/winbindd/winbindd.c
@@ -727,12 +727,17 @@ static void new_connection(int listen_sock, bool privileged)
 
 static void remove_client(struct winbindd_cli_state *state)
 {
+       char c = 0;
+
        /* It's a dead client - hold a funeral */
        
        if (state == NULL) {
                return;
        }
-               
+
+       /* tell client, we are closing ... */
+       write(state->sock, &c, sizeof(c));
+
        /* Close socket */
                
        close(state->sock);