Date: Tue, 3 Feb 2015 23:42:35 -0800 From: John-Mark Gurney <jmg@funkthat.com> To: Erich Dollansky <erichsfreebsdlist@alogt.com> Cc: freebsd-stable@freebsd.org Subject: Re: top, fixed buffer length in utils.c Message-ID: <20150204074235.GX27103@funkthat.com> In-Reply-To: <20150203200135.57c8c236@B85M-HD3-0.alogt.com> References: <20150201175159.7fa88d16@B85M-HD3-0.alogt.com> <20150203003307.GG27103@funkthat.com> <20150203200135.57c8c236@B85M-HD3-0.alogt.com>
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Erich Dollansky wrote this message on Tue, Feb 03, 2015 at 20:01 +0800:
> On Mon, 2 Feb 2015 16:33:07 -0800
> John-Mark Gurney <jmg@funkthat.com> wrote:
>
> > Erich Dollansky wrote this message on Sun, Feb 01, 2015 at 17:51
> > +0800:
> > > int can be 64 bits on a amd64 machine. Why is the author of this
> > > code so sure that we will never cross the 32 bit boundary?
> >
> > Per others, int is currently 32bits on all platforms we support...
> >
> > I guess adding:
> > CTASSERT(sizeof(int) <= 4);
> >
> > would help fix your concern? at least now the expectation is codified
> > and if it breaks, the build will break..
> >
> of course. Either avoid the run-time problem or get an error message
> and things cannot create hidden problem.
Ok, I've generated this patch:
Index: utils.c
===================================================================
--- utils.c (revision 277938)
+++ utils.c (working copy)
@@ -58,6 +58,7 @@ char *str;
* ever convert will be 2^32-1, which is 10
* digits.
*/
+_Static_assert(sizeof(int) <= 4, "buffer too small for this sized int");
char *itoa(val)
I couldn't use CTASSERT because including sys/param.h and sys/systm.h
per man page didn't work.. apparently for userland it's different and
requires additional headers... It appears that we define it in
sys/cdefs.h which gets included, so this work for both clang and gcc...
I'll commit it soon unless someone objects...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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