Date: Thu, 17 May 2001 15:11:37 +0300 From: Ruslan Ermilov <ru@FreeBSD.ORG> To: Nik Clayton <nik@FreeBSD.ORG>, arch@FreeBSD.ORG Subject: Re: [PATCH] syscons ioctl() to grab text mode buffer Message-ID: <20010517151137.E55371@sunbay.com> In-Reply-To: <20010517150823.A39834@ringworld.oblivion.bg>; from roam@orbitel.bg on Thu, May 17, 2001 at 03:08:23PM %2B0300 References: <20010517121902.A3047@catkin.nothing-going-on.org> <20010517145209.C55371@sunbay.com> <20010517150823.A39834@ringworld.oblivion.bg>
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On Thu, May 17, 2001 at 03:08:23PM +0300, Peter Pentchev wrote:
> On Thu, May 17, 2001 at 02:52:09PM +0300, Ruslan Ermilov wrote:
> > On Thu, May 17, 2001 at 12:19:02PM +0100, Nik Clayton wrote:
> > > Two things for review.
> > >
> > [...]
> > > The second, scrshot.c uses the ioctl to dump the contents of the video
> > > memory to stdout. Usage is
> > >
> > > scrshot /dev/ttyv0 > shot.scr
> > >
> > There are some style(9) and -security issues with this:
> >
> > --- scrshot.c~ Thu May 17 14:42:40 2001
> > +++ scrshot.c Thu May 17 14:50:22 2001
> [snip[
> > - result = ioctl(fd, CONS_GETINFO, &info);
> > - if (result != 0) {
> > - perror("getinfo failed");
> > - exit(1);
> > - }
> > + if (ioctl(fd, CONS_GETINFO, &info) == -1)
> > + err(1, "ioctl(CONS_GETINFO)");
>
> Wouldn't it be better to check for < 0 here, too?
> More compatible in the long run..
>
Nope, see RETURN VALUES in ioctl(2) manpage; see POSIX then.
All sysctl's return -1 on error, not <0.
Cheers,
--
Ruslan Ermilov Oracle Developer/DBA,
ru@sunbay.com Sunbay Software AG,
ru@FreeBSD.org FreeBSD committer,
+380.652.512.251 Simferopol, Ukraine
http://www.FreeBSD.org The Power To Serve
http://www.oracle.com Enabling The Information Age
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