Re: xfstests, weird looking code in src/resvtest.c

Dave Chinner
2014-06-17T23:06:33Z

On Tue, Jun 17, 2014 at 11:20:44AM -0500, scameron@beardog.cce.hp.com wrote:
>
> This code in xfstests src/resvtest.c looks pretty strange:
>
> ...
> 32 char *readbuffer, *writebuffer;
> ...
> 70 readbuffer = memalign(psize, bsize);
> 71 writebuffer = memalign(psize, bsize);
> 72 if (!readbuffer || !writebuffer) {
> 73 perror("open");
> 74 exit(1);
> 75 }
> 76 memset(writebuffer, 'A', sizeof(writebuffer));
>
> ^^^ writebuffer is a pointer, so using sizeof(writebuffer) here is
> odd. Is it intentional to put either 4 or 8 A's into writebuffer
> depending on sizeof a pointer? Seems unlikely.
>
> 110 while (++n < iterations) {
> 111 char *p;
> 112 int numerrors;
> 113
> 114 if (write(writefd, writebuffer, sizeof(writebuffer)) < 0) {
> 115 perror("write");
> 116 exit(1);
> 117 }
>
> So that write will write sizeof a pointer's worth of whatever's in writebuffer.
> Intentional? Again, seems unlikely.
>
> This seems like maybe somebody initially declared writebuffer as an array, but
> later went back and changed it to a pointer, but forgot to fixup everywhere that
> referred to sizeof(writebuffer).
>
> I would have sent a patch but I'm not sure what this code is trying to do.
>
> gcc 4.4.7 (what comes with RHEL6u5) doesn't warn about this, but 4.8.3 does.

There's a recent patch on the fstests list (fstests@vger.kernel.org)
that fixes this that I haven't picked up yet.

For actual test harness issues, you should use
fstests@vger.kernel.org now, not xfs@oss.sgi.com...

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com

_______________________________________________
xfs mailing list
xfs@oss.sgi.com