Re: ntdll/server and unix_fd handling

[Alexandre Julliard]

Kai Blin  writes:
> After some more digging, upstream of the get_sock_fd call, the 
> server_get_unix_fd() call always gets the same fd, either from wineserver or 
> from the cache. wine_server_handle_to_fd() then seems to call dup() on the 
> unix_fd. This seems to be needed because for some reason unix fds are used 
> only temporary, so get_sock_fd is always followed by release_sock_fd(), which 
> calls a close(). Why is this handled this way?

Because the file descriptor has to remain valid until it is released, so
we have to dup() it as it may get closed from a different thread in the
meantime. We can avoid the dup() in some cases in ntdll, but not in
other dlls since it would let anybody screw up the fd cache.