Change global in-fifos from O_RDWR to O_RDONLY

O_RDWR is a dirty hack to get around the issue of infinite
EOFs while reading an in-FIFO.
Instead, stop breaking POSIX and set the FIFOs to O_RDONLY.

In case a read returns EOF (r == 0), we reopen the fd.

Same will be applied to the friend-fifos (especially file_in),
helping us get rid of strange timeouts and heuristics and
rather solve the problem the POSIX-way.

The only downside to this is that we are blind for writes
to the in-FIFOs between catching read == 0 and close(), but this is
not an issue.

To make reopening as easy as possible, I added a dirfd
to all slots.
While at it, I changed the initial setup and removed the chdir()
in favor of the POSIX-2008-compliant *at-functions.
This lets us do stuff without having to use snprintf to build
paths and is more bulletproof even in case the directory is
renamed.

0 files changed, 0 insertions, 0 deletions