On Wed, Sep 25, 2024 at 04:53:49PM +0200, Pablo Neira Ayuso wrote:
> On Tue, Sep 03, 2024 at 04:53:46PM +0200, Ahelenia Ziemiańska wrote:
> > On Tue, Sep 03, 2024 at 10:22:09AM +0200, Pablo Neira Ayuso wrote:
> > > On Tue, Sep 03, 2024 at 04:16:21AM +0200, Ahelenia Ziemiańska wrote:
> > > > The manual says
> > > > COMMANDS
> > > > These options specify the particular operation to perform.
> > > > Only one of them can be specified at any given time.
> > > >
> > > > -L --dump
> > > > List connection tracking or expectation table
> > > >
> > > > So, naturally, "conntrack -Lo extended" should work,
> > > > but it doesn't, it's equivalent to "conntrack -L",
> > > > and you need "conntrack -L -o extended".
> > > > This violates user expectations (borne of the Utility Syntax Guidelines)
> > > > and contradicts the manual.
> > > >
> > > > optarg is unused, anyway. Unclear why any of these were :: at all?
> > > Because this supports:
> > > -L
> > > -L conntrack
> > > -L expect
> > Well that's not what :: does, though; we realise this, right?
> >
> > "L::" means that getopt() will return
> > "-L", "conntrack" -> 'L',optarg=NULL
> > "-Lconntrack" -> 'L',optarg="conntrack"
> > and the parser for -L (&c.) doesn't... use optarg.
> Are you sure it does not use optarg?
>
> static unsigned int check_type(int argc, char *argv[])
> {
> const char *table = get_optional_arg(argc, argv);
>
> and get_optional_arg() uses optarg.
This I've missed, but actually my diagnosis still holds:
static unsigned int check_type(int argc, char *argv[])
{
const char *table = get_optional_arg(argc, argv);
/* default to conntrack subsystem if nothing has been specified. */
if (table == NULL)
return CT_TABLE_CONNTRACK;
static char *get_optional_arg(int argc, char *argv[])
{
char *arg = NULL;
/* Nasty bug or feature in getopt_long ?
* It seems that it behaves badly with optional arguments.
* Fortunately, I just stole the fix from iptables ;) */
if (optarg)
return arg;
So, if you say -Lanything, then
optarg=anything
get_optional_arg=(null)
(notice that it says "return arg;", not "return optarg;",
i.e. this is "return NULL").
It /doesn't/ use optarg, because it explicitly treats an optarg as no optarg.
It's unclear to me what the comment is referencing,
but I'm assuming some sort of confusion with what :: does?
Anyway, that if(){ can be removed now, since it can never be taken now.
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