[libvirt] [PATCH 1/2] util: Add function to check if string contains some chars

Sławek Kapłoński slawek at kaplonski.pl
Tue Oct 18 19:55:57 UTC 2016


Hello,

Thx for review. Please read my answear inline.

-- 
Best regards / Pozdrawiam
Sławek Kapłoński
slawek at kaplonski.pl

On Tue, 18 Oct 2016, Michal Privoznik wrote:

> On 14.10.2016 04:53, Sławek Kapłoński wrote:
> > This new function can be used to check if e.g. name of XML node
> > don't contains forbidden chars like "/" or new-line.
> > ---
> >  src/conf/network_conf.c  | 2 +-
> >  src/libvirt_private.syms | 1 +
> >  src/util/virstring.c     | 9 +++++++++
> >  src/util/virstring.h     | 1 +
> >  4 files changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
> > index aa39776..949d138 100644
> > --- a/src/conf/network_conf.c
> > +++ b/src/conf/network_conf.c
> > @@ -2117,7 +2117,7 @@ virNetworkDefParseXML(xmlXPathContextPtr ctxt)
> >          goto error;
> >      }
> >  
> > -    if (strchr(def->name, '/')) {
> > +    if (virStringHasChars(def->name, "/")) {
> >          virReportError(VIR_ERR_XML_ERROR,
> >                         _("name %s cannot contain '/'"), def->name);
> 
> Usually, in one patch we introduce a function and then in a subsequent
> one we switch the rest of the code into using it. But okay, I can live
> with this too.
> 
> >          goto error;
> > diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> > index 55b6a24..6f41234 100644
> > --- a/src/libvirt_private.syms
> > +++ b/src/libvirt_private.syms
> > @@ -2435,6 +2435,7 @@ virStringEncodeBase64;
> >  virStringFreeList;
> >  virStringFreeListCount;
> >  virStringGetFirstWithPrefix;
> > +virStringHasChars;
> >  virStringHasControlChars;
> >  virStringIsEmpty;
> >  virStringIsPrintable;
> > diff --git a/src/util/virstring.c b/src/util/virstring.c
> > index 4a70620..7799d87 100644
> > --- a/src/util/virstring.c
> > +++ b/src/util/virstring.c
> > @@ -975,6 +975,15 @@ virStringStripIPv6Brackets(char *str)
> >  }
> >  
> >  
> > +bool
> > +virStringHasChars(const char *str, const char *chars)
> > +{
> > +    if (strpbrk(str, chars))
> > +        return true;
> > +    return false;
> > +}
> 
> This, however, makes not much sense. I mean, this function has no added
> value to pain strpbrk(). What I suggested in one of previous reviews was
> that this function should report an error too. In that case, it will
> immediately have added value and thus it will be handy to use it.
> Perhaps you are afraid that error message might change in some cases?
> That's okay, we don't make any promises about error messages.
> 

I agree that in fact it don't have too much sense but I'm not sure that
it would be good to report error here. First of all, it could be that in
some cases it could be used to check if function have required chars so
there is no easy way to check which result is error in fact.
Second thing (maybe here I'm wrong) places where I wanted to use this
function are reporting error VIR_ERR_XML_ERROR and I'm not sure it is
good place to report such error in "string lib".
So maybe better solution would be just use strbprk (or strchr) in
src/network/bridge_driver.c to check if name contains \n char and not
introduce any new function to such check? What You think about that?

> > +
> > +
> >  static const char control_chars[] =
> >      "\x01\x02\x03\x04\x05\x06\x07"
> >      "\x08" /* \t \n */ "\x0B\x0C" /* \r */ "\x0E\x0F"
> > diff --git a/src/util/virstring.h b/src/util/virstring.h
> > index 8854d5f..7f2c96d 100644
> > --- a/src/util/virstring.h
> > +++ b/src/util/virstring.h
> > @@ -272,6 +272,7 @@ char *virStringReplace(const char *haystack,
> >      ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
> >  
> >  void virStringStripIPv6Brackets(char *str);
> > +bool virStringHasChars(const char *str, const char *chars);
> >  bool virStringHasControlChars(const char *str);
> >  void virStringStripControlChars(char *str);
> >  
> > 
> 
> Michal
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