Re: [PATCH v2 bpf] tools: bpftool: Add missing close before bpftool net attach exit

From: John Fastabend
Date: Wed Nov 11 2020 - 03:44:28 EST


wanghai (M) wrote:
>
> 在 2020/11/10 12:33, John Fastabend 写道:
> > Wang Hai wrote:
> >> progfd is created by prog_parse_fd(), before 'bpftool net attach' exit,
> >> it should be closed.
> >>
> >> Fixes: 04949ccc273e ("tools: bpftool: add net attach command to attach XDP on interface")
> >> Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx>
> >> ---

[...]

> > Alternatively we could add an 'err = 0' here, but above should never
> > return a value >0 as far as I can see.
> It's true that 'err > 0' doesn't exist currently , but adding 'err = 0'
> would make the code clearer. Thanks for your advice.
> >> +cleanup:
> >> + close(progfd);
> >> + return err;
> >> }
> >>
> >> static int do_detach(int argc, char **argv)
> >> --
> >> 2.17.1
> >>
> Can it be fixed like this?
>
> --- a/tools/bpf/bpftool/net.c
> +++ b/tools/bpf/bpftool/net.c
> @@ -578,8 +578,8 @@ static int do_attach(int argc, char **argv)
>
>         ifindex = net_parse_dev(&argc, &argv);
>         if (ifindex < 1) {
> -               close(progfd);
> -               return -EINVAL;
> +               err = -EINVAL;
> +               goto cleanup;
>         }
>
>         if (argc) {
> @@ -587,8 +587,8 @@ static int do_attach(int argc, char **argv)
>                         overwrite = true;
>                 } else {
>                         p_err("expected 'overwrite', got: '%s'?", *argv);
> -                       close(progfd);
> -                       return -EINVAL;
> +                       err = -EINVAL;
> +                       goto cleanup;
>                 }
>         }
>
> @@ -597,16 +597,19 @@ static int do_attach(int argc, char **argv)
>                 err = do_attach_detach_xdp(progfd, attach_type, ifindex,
>                                            overwrite);
>
> -       if (err < 0) {
> +       if (err) {
>                 p_err("interface %s attach failed: %s",
>                       attach_type_strings[attach_type], strerror(-err));
> -               return err;
> +               goto cleanup;
>         }
>
>         if (json_output)
>                 jsonw_null(json_wtr);
>
> -       return 0;
> +       ret = 0;
> +cleanup:
> +       close(progfd);
> +       return err;
>  }
>

LGTM. Send a v3.