Re: [Qemu-devel] [PATCH] 9p: Convert use of atoi to qemu_strtol to allow error checking

[Greg Kurz]

On Tue, 13 Mar 2018 15:52:41 +0000
Stefan Hajnoczi <address@hidden> wrote:

> On Tue, Mar 13, 2018 at 3:25 PM, nee <address@hidden> wrote:
> > On Mon, Mar 12, 2018 at 1:21 PM, Greg Kurz <address@hidden> wrote:  
> >> On Mon, 12 Mar 2018 13:08:29 +0000
> >> Daniel P. Berrangé <address@hidden> wrote:
> >>  
> >>> On Mon, Mar 12, 2018 at 02:02:29PM +0100, Greg Kurz wrote:  
> >>> > On Mon, 12 Mar 2018 07:12:52 -0500
> >>> > Eric Blake <address@hidden> wrote:
> >>> >  
> >>> > > On 03/11/2018 03:12 PM, Nia Alarie wrote:  
> >>> > > > Signed-off-by: Nia Alarie <address@hidden>
> >>> > > > ---
> >>> > > >   hw/9pfs/9p.c | 12 ++++++++++--
> >>> > > >   1 file changed, 10 insertions(+), 2 deletions(-)
> >>> > > >  
> >>> > >  
> >>> > > >       } else if (perm & P9_STAT_MODE_LINK) {
> >>> > > > -        int32_t ofid = atoi(extension.data);
> >>> > > > -        V9fsFidState *ofidp = get_fid(pdu, ofid);
> >>> > > > +        long ofid;
> >>> > > > +        V9fsFidState *ofidp;
> >>> > > > +
> >>> > > > +        if (qemu_strtol(extension.data, NULL, 10, &ofid) ||
> >>> > > > +            ofid > INT32_MAX || ofid < INT32_MIN) {  
> >>> > >
> >>> > > Dan has a pending patch that will add qemu_strtoi, which might be a
> >>> > > nicer fit for this situation:
> >>> > >
> >>> > > https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg00952.html
> >>> > >
> >>> > > int32_t is not necessarily int, but all platforms that compile qemu 
> >>> > > have
> >>> > > 'int32_t' and 'int' both at 32 bits, so it's simpler to change to 'int
> >>> > > ofid' and use Dan's function than it is to parse to long and then do
> >>> > > bounds checking.  Except that Dan still needs to post an updated 
> >>> > > version
> >>> > > of his patch...
> >>> > >  
> >>> >
> >>> > I wasn't aware of Dan's patch but I agree it would result in a nicer
> >>> > change for 9p. This being said, tomorrow is soft freeze... is there
> >>> > a chance Dan's patch reaches master anytime soon ?  
> >>>
> >>> I just sent an update of my series. If it gets acked by Eric, I'd be able
> >>> to send a pull request today.
> >>>
> >>> Regards,
> >>> Daniel  
> >>
> >> Great !
> >>
> >> Nia,
> >>
> >> Could you please respin your patch on top of Daniel's series, using
> >> qemu_strtoui() ?
> >>
> >> Thanks,
> >>
> >> --
> >> Greg  
> >
> > I'm a bit unclear on how this works so I thought I'd ask here before I
> > send any more patches - this is CCed to my mentors as well. It's
> > "tomorrow" now, but I don't understand how soft freezes work or the
> > process beyond "I send this patch to qemu-devel and people say if I
> > should re-send it with changes, or that it's been accepted" :)  
> 
> Don't worry about the soft freeze for now.  The soft freeze is the
> deadline for new features.  People are trying to get their new
> features into the upcoming QEMU 2.12 release.
> 
> Either Greg will still merge your patch after soft freeze since it can
> be considered a bug fix (fixes are allowed during freeze).  Or Greg
> might keep your patch queued until the QEMU 2.12 release has been made
> (around April 17th 2018).
> 

Nia (or Nee?) 's patch is a bug fix. I'll happily merge it when it's
ready.

> The QEMU release schedule is here (but don't worry about it):
> https://wiki.qemu.org/Planning/2.12
> 
> I suggest taking the following action.  Wait until Daniel Berrange's
> pull request is merged (it will probably happen today):
> https://lists.gnu.org/archive/html/qemu-devel/2018-03/msg03662.html
> 
> Then rebase your patch onto the latest qemu.git/master so you can take
> advantage of qemu_strtoi().  You can use "git rebase -i origin/master"
> to do this.
> 
> Recompile/test your patch and then send it with "[PATCH v2] 9p:
> Convert use of atoi to qemu_strtoi to allow error checking" as the
> email subject.
> 

Nia had already sent a v2, which got comments, so it'll be v3.

> > There are several more conversions from ato* to qemu_strto* I'd like
> > to submit from now on. Should I send them as using qemu_strtol now, to
> > get them "out there" before my own personal deadlines, and send
> > further patches to convert them to qemu_strtoi later, or should I
> > submit patches that use qemu_strtoi? I'm not sure of the current
> > status of Daniel's patches.  
> 
> Daniel's patches will be in qemu.git/master (probably) later today.  I
> suggest waiting for them and using qemu_strtoi() where using an int
> type is appropriate.
> 
> If you have questions along the way, feel free to ask on the QEMU IRC
> channel: #qemu on irc.oftc.net.
> 
> Stefan

Agreed with all of the above. Thanks Stefan for providing this comprehensive
explanation to Nia.

Cheers,

--
Greg