lio_listio: validate aio_lio_opcode

[asomers]

Summary

Previously, we would accept any kind of LIO_* opcode, including ones
that were intended for in-kernel use only like LIO_SYNC (which is not
defined in userland). The situation became more serious with
022ca2fc7fe08d51f33a1d23a9be49e6d132914e. After that revision, setting
aio_lio_opcode to LIO_WRITEV or LIO_READV would trigger an assertion.

Note that POSIX does not specify what should happen if aio_lio_opcode is
invalid.

MFC-with: 022ca2fc7fe08d51f33a1d23a9be49e6d132914e

Test Plan

test case added

[0mp]

OK from manpages.

[jhb]

lib/libc/sys/aio_return.2

81

I would perhaps simplify this to just:

The I/O operation was submitted with
.Fn lio_listio ,
and the value of
.Fa aio_lio_opcode
is invalid.

tests/sys/aio/lio_test.c

241

It is perhaps better to call aio_error() here instead of aio_return(). lio_listio()'s man page says to call aio_error().

[asomers]

Closed by https://cgit.freebsd.org/src/commit/?id=ff1a307801994e18a87929898225f09d31f3e1fa .