On 25.12.2017 03:42, John Nemeth wrote:
> On Dec 24, 9:37pm, Mouse wrote:
> }
> } > http://netbsd.org/~kamil/patch-00039-obsolete-SYS_pipe.txt
> }
> } I see no pipe2(2), nor change from pipe(2) to pipe(3) (with an xref to
> } pipe2(2)), both of which, it seems to me, should be part of this.
>
> From: http://netbsd.gw.com/cgi-bin/man-cgi?pipe2+2+NetBSD-current
>
> HISTORY
> A pipe() function call appeared in Version 6 AT&T UNIX. The pipe2()
> function is inspired from Linux and appeared in NetBSD 6.0.
>
> My NetBSD 7.x systems have the manpage as well. One might wish to
> look for manpages on a system newer then 1.4T. :->
>
> The big thing is that I don't see what the difference between
> pipe(2) and pipe2(2) are, other then that pipe2(2) takes an extra
> flags argument, i.e. I don't see how it solves the problem stated
> in the original message.
>
The original problem:
__syscall(SYS_pipe2, ... works, while syscall(SYS_pipe, ... is not
easily usable.
It's stated in the BUGS section of syscall(2):
BUGS
There is no way to simulate system calls that have multiple return
values
such as pipe(2).
This propagates to rump special case handling and requests to use
assembly snippets for every supported CPU. It might save little space in
the kernel, but also save time of a developer porting the OS to a new
CPU. Nobody will need to spend precious time on pipe.S anymore.
I cannot remove entirely SYS_pipe, as it is used in software that bypass
libc (like golang). Once compat_80 will be disabled at least in the
default kernels, it will be gone from regular users. pipe2(2) is there
since 5.99.x, and switching golang and other users to SYS_pipe2 won't
affect any users of supported kernel versions.
I've just entirely removed sys_pipe from rump and adjusted the needed
code. There is certainly more room now to further simplify the rump
retval[] code,but I have omitted it.
I've skipped the change renaming or splitting the man pages.
> }-- End of excerpt from Mouse
>
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