fix lxc-attach usage

This makes it match the manpage and be consistent with lxc-execute

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
fortify: check the value returned from write(2)

Also check that we wrote the amount we expected to. The write on the pty
is blocking but we could still get a short write on EINTR, so we should
SYSERROR it.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
fortify: minor cleanups for unused variables, stricter types

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
fortify: use reentrant safe strtok_r

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
fix checking hook script exit code

pclose returns the exit status from wait, we need to check that to see if
the script itself failed or not. Tested a script that returned 0, 1, and
also one that did a sleep and then was killed by a signal.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>