Re: [PATCH nft] main: allow for getopt parser from top-level scope only

[Phil Sutter <phil@nwl.cc>]

Hi,

On Thu, Dec 12, 2019 at 07:28:11PM +0100, Pablo Neira Ayuso wrote:
> On Thu, Dec 12, 2019 at 06:45:35PM +0100, Phil Sutter wrote:
> > On Thu, Dec 12, 2019 at 06:14:55PM +0100, Pablo Neira Ayuso wrote:
> > [...]
> > > diff --git a/src/main.c b/src/main.c
> > > index fde8b15c5870..c96953e3cd2f 100644
> > > --- a/src/main.c
> > > +++ b/src/main.c
> > > @@ -202,29 +202,107 @@ static const struct {
> > >  	},
> > >  };
> > >  
> > > +struct nft_opts {
> > > +	char		**argv;
> > > +	int		argc;
> > > +};
> > > +
> > > +static int nft_opts_init(int argc, char * const argv[], struct nft_opts *opts)
> > > +{
> > > +	uint32_t scope = 0;
> > > +	char *new_argv;
> > > +	int i;
> > > +
> > > +	opts->argv = calloc(argc + 1, sizeof(char *));
> > > +	if (!opts->argv)
> > > +		return -1;
> > > +
> > > +	for (i = 0; i < argc; i++) {
> > > +		if (scope > 0) {
> > > +			if (argv[i][0] == '-') {
> > > +				new_argv = malloc(strlen(argv[i]) + 2);
> > > +				if (!new_argv)
> > > +					return -1;
> > > +
> > > +				sprintf(new_argv, "\\-%s", &argv[i][1]);
> > > +				opts->argv[opts->argc++] = new_argv;
> > > +				continue;
> > > +			}
> > > +		} else if (argv[i][0] == '{') {
> > > +			scope++;
> > > +		} else if (argv[i][0] == '}') {
> > > +			scope--;
> > > +		}
> > 
> > This first char check is not reliable, bison accepts commands which lack
> > spaces in the relevant places:
> > 
> > | # nft add chain inet t c{ type filter hook input priority filter\; }
> > | # echo $?
> > | 0
> 
> Yes, it won't catch that case. Do you think it is worth going further
> in this preprocessing?

What about a different approach, namely to iterate over argv in reverse,
reordering those *argv until **argv != '-'? One would have to make sure
not to mess ordering, but that should be the only requirement to get
expected results in any situation.

Cheers, Phil