Re: [9fans] Why do we need syspipe() ?

["roger peppe" <rogpeppe@gmail.com>]

i've sometimes thought that the trick used by #d etc could
be made more transparent by providing a genuine capability
service for fds, in the form of a system call, for instance

  getfdcap(int fd, char *buf, int len)

then instead of just writing the fd itself, you'd write
the capability - thus the write can bridge several
namespaces, as long as it ends up in the same kernel,
which can then utilise the capability.

the fact that this also provides the possibility of implementing
sendfd might or might not be an advantage.