Date: Mon, 21 Jul 1997 14:14:39 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: skynyrd@opus.cts.cwu.edu (Chris Timmons) Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: suggested enhancement: linux_ioctl.c diagnostic output Message-ID: <199707210444.OAA21177@genesis.atrad.adelaide.edu.au> In-Reply-To: <Pine.BSF.3.95.970720102920.26163B-100000@opus.cts.cwu.edu> from Chris Timmons at "Jul 20, 97 10:46:36 am"
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Chris Timmons stands accused of saying:
>
> I tried to get some comments about this from -emulation but perhaps the
> subject line wasn't to the point enough.
It was; you're just buried in my to-do list 8(
> If you read down to the end I've sketched out a proposed change to
> linux_ioctl.c. I'd like to know:
>
> 1. Overall is this a worthwile change?
Yes.
> 2. Is the long comment which documents linux ioctl encoding
> inappropriate for this source file?
No.
> 3. I see from style(9) that I should have spaces between the
> operands to the bitwise and operator. What about the
> style of the nested conditional? I guess there might also be
> some unnecessary parens in the printf argument list.
Bruce will have his own interpretation; I would be inclined to say :
uprintf("LINUX: unimplemented ioctl: fd=%d, cmd=0x%lx (IO%s%s, '%c', %lu, %lu)\n",
args->fd, args->cmd,
(args->cmd & 0x400000000) ? "W" : "",
(args->cmd & 0x800000000) ? "R" : "",
((args->cmd & 0x0000ff00) >> 8) >= 0x20)
? (char)((args->cmd & 0x0000ff00)>>8)
: '?',
args->cmd & 0xff,
(args->cmd & 0x3fff0000) >> 16);
return EINVAL;
}
The other implementation of the IO[WR] decoding I would consider would
use a small lookup table and a large shift to generate an index. The
massively nested ? set you used makes for very difficult reading.
I don't think that the performance of the printf() should be a
consideration in contrast to the usefulness of verbose output.
--
]] Mike Smith, Software Engineer msmith@gsoft.com.au [[
]] Genesis Software genesis@gsoft.com.au [[
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