Re: [PATCH] tools/xl: Fix trim() following c/s e316316 "xl: Rewrite trim()"

[Wei Liu <wei.liu2@citrix.com>]

On Thu, Jul 16, 2015 at 10:53:02PM +0100, Andrew Cooper wrote:
> On 16/07/2015 21:47, Wei Liu wrote:
> > On Thu, Jul 16, 2015 at 08:18:31PM +0100, Andrew Cooper wrote:
> >> c/s e316316 "xl: Rewrite trim()" uses the wrong indirection of
> >> 'output', causing memory corruption for all callers.
> >>
> >> Introduce a new local variable, making the code more obviously
> >> correct.
> >>
> >> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> >> CC: Ian Campbell <Ian.Campbell@citrix.com>
> >> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> >> CC: Wei Liu <wei.liu2@citrix.com>
> > Acked-by: Wei Liu <wei.liu2@citrix.com>
> >
> > One nit below.
> >
> >> ---
> >>  tools/libxl/xl_cmdimpl.c |    8 +++++---
> >>  1 file changed, 5 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> >> index 37d4af6..0cc9f8b 100644
> >> --- a/tools/libxl/xl_cmdimpl.c
> >> +++ b/tools/libxl/xl_cmdimpl.c
> >> @@ -663,10 +663,12 @@ static void trim(char_predicate_t predicate, const char *input, char **output)
> >>          ;
> >>  
> >>      size_t len_nonnull = after - first;
> >> +    char *result = xmalloc(len_nonnull + 1);
> >>  
> > Can you move the declaration of result to the beginning of this
> > function?
> 
> I can, but why in particular?  It is adjacent to the declaration of
> len_nonnull.
> 

C90 forbids this. Not sure how much we care about that and I'm probably
bicksheding too much.

Wei.

> ~Andrew