There are two reasons for this:
* We should be able to pass file descriptors without sending any data.
* We could send zero-length iovecs anyway (but we shouldn't have to do this).
Also, msg_iovlen is already a u_int, so delete a bunch of casts.
* the first one would cause an unnecessary malloc() of iovec storage for
a msg_iovlen of UIO_SMALLIOV although the required amount of memory has
been allocated on the stack.
* the second one would cause a recvmsg() or sendmsg() with a msg_iovlen of
UIO_MAXIOV to fail with EMSGSIZE, which is also a violation of XNS5.
The read/write system calls return ssize_t because -1 is used to indicate
error, therefore the transfer size MUST be limited to SSIZE_MAX, otherwise
garbage can be returned to the user.
There is NO change from existing behavior here, only a more precise
definition of that the semantics are, except in the Alpha case, where
the full SSIZE_MAX transfer size can now be realized (ssize_t is 64-bit
on the Alpha).
- Add a comment describing my feelings about this interface, in general.
- Remove the COMPAT_OLDSOCK length hack. Instead, if the socket argument
is too long to fit in an mbuf, allocate enough external storage to
hold it.
- If the socket argument is a sockaddr, don't allow the length to be
greater than 255, as that would overflow sa_len.
Many thanks to enami tsugutomo <enami@cv.sony.co.jp> for his sanity checking.
* Fix arguments to various copyin()/copyout() invocations, to avoid
gratuitous casts.
* Some KNF formatting fixes
* Change sockargs()'s second argument to be a const void *, to help
with dealing with the syscall argument type fixups/const poisoning.
sysv_shm.c: make shm_find_segment_by_shmid global so it can be used by
COMPAT_HPUX. There should be a better way...
rest: Add #ifdef COMPAT_HPUX where needed
mycroft