[dpdk-dev] [PATCH] lib/cmdline: init parse result memeory

[Xueming(Steven) Li]

Hi Olivier,

> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz at 6wind.com]
> Sent: Thursday, December 7, 2017 10:48 PM
> To: Xueming(Steven) Li <xuemingl at mellanox.com>
> Cc: dev at dpdk.org
> Subject: Re: [PATCH] lib/cmdline: init parse result memeory
> 
> On Wed, Nov 15, 2017 at 11:54:02PM +0800, Xueming Li wrote:
> > Initialize binary result memory before parsing to avoid garbage in
> > parsing result.
> >
> > Signed-off-by: Xueming Li <xuemingl at mellanox.com>
> > ---
> >  lib/librte_cmdline/cmdline_parse.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/lib/librte_cmdline/cmdline_parse.c
> > b/lib/librte_cmdline/cmdline_parse.c
> > index 3e12ee54f..9124758f1 100644
> > --- a/lib/librte_cmdline/cmdline_parse.c
> > +++ b/lib/librte_cmdline/cmdline_parse.c
> > @@ -267,6 +267,8 @@ cmdline_parse(struct cmdline *cl, const char * buf)
> >  	if (!cl || !buf)
> >  		return CMDLINE_PARSE_BAD_ARGS;
> >
> > +	memset(tmp_result.buf, 0, sizeof(tmp_result.buf));
> > +
> >  	ctx = cl->ctx;
> >
> >  	/*
> 
> 
> Did you see an issue (a bug or a crash) without the memset()?
> Or is it to avoid filling unused fields in the parsed struct?
Yes, I'm using same struct for some similar commands, have to avoid filling 
unused fields.

> 
> I'm not sure if your patch is enough: cmdline_parse() calls match_inst()
> for each registered command. If a command partially matches (only the
> first tokens), the buffer is modified. So the next one will start with a
> dirty buffer.
> 
> I suggest to put the memset() in match_inst() instead. Something like this:
> 
> 	if (resbuf != NULL)
> 		memset(resbuf, 0, resbuf_size);
> 
> 
> It will reset the buffer before using it.
It was there for performance concern, since the buffer could be tainted, I'll
upload a new version according to your suggestion, appreciate your suggestion.

> 
> Olivier