Checkpoint and restore of fifo is similar to
pipes c/r except the pipe end-points are named
file.
Because the fifo has a name we use regular files
facility for fifo path c/r.
Still there is a trick used to "open" fifo:
the opening procedure migh sleep if a fifo's peer
is not yet opened, so before doing a real open
we yield a fake open procedure (with O_RDWR flag)
which prevents us from sleeping even if peer
is not yet ready. Also we need writable fifo
end to restore data queued.
v2:
- add open/priv members to reg_file_info
- make open_fifo_fd to use open_fe_fd
- comment on pipe_id
- make sure the fifo data is not restored twice
v3:
- drop useless fixme comment and add sane one
v4:
- Use restore_data flag to escape data restore duplication
- Use S_ISREG for file contents copying
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
