On Fri, Sep 9, 2022 at 10:16 AM <sdf@xxxxxxxxxx> wrote:
>
> On 09/09, Wang Yufen wrote:
> > Move snprintf and len check to common helper pathname_concat() to make the
> > code simpler.
>
> > Signed-off-by: Wang Yufen <wangyufen@xxxxxxxxxx>
> > ---
> > tools/lib/bpf/libbpf.c | 74
> > ++++++++++++++++++--------------------------------
> > 1 file changed, 27 insertions(+), 47 deletions(-)
>
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 5854b92..238a03e 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -2096,20 +2096,31 @@ static bool get_map_field_int(const char
> > *map_name, const struct btf *btf,
> > return true;
> > }
>
> > -static int build_map_pin_path(struct bpf_map *map, const char *path)
> > +static int pathname_concat(const char *path, const char *name, char *buf)
> > {
> > - char buf[PATH_MAX];
> > int len;
>
> > - if (!path)
> > - path = "/sys/fs/bpf";
> > -
> > - len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
> > + len = snprintf(buf, PATH_MAX, "%s/%s", path, name);
> > if (len < 0)
> > return -EINVAL;
> > else if (len >= PATH_MAX)
> > return -ENAMETOOLONG;
>
> > + return 0;
> > +}
> > +
> > +static int build_map_pin_path(struct bpf_map *map, const char *path)
> > +{
> > + char buf[PATH_MAX];
> > + int err;
> > +
> > + if (!path)
> > + path = "/sys/fs/bpf";
> > +
> > + err = pathname_concat(path, bpf_map__name(map), buf);
> > + if (err)
> > + return err;
> > +
> > return bpf_map__set_pin_path(map, buf);
> > }
>
> > @@ -7959,17 +7970,8 @@ int bpf_object__pin_maps(struct bpf_object *obj,
> > const char *path)
> > continue;
>
> > if (path) {
> > - int len;
> > -
> > - len = snprintf(buf, PATH_MAX, "%s/%s", path,
> > - bpf_map__name(map));
> > - if (len < 0) {
> > - err = -EINVAL;
> > - goto err_unpin_maps;
> > - } else if (len >= PATH_MAX) {
> > - err = -ENAMETOOLONG;
>
> [..]
>
> > + if (pathname_concat(path, bpf_map__name(map), buf))
> > goto err_unpin_maps;
> > - }
>
> You're breaking error reporting here and in a bunch of other places.
> Should be:
>
> err = pathname_concat();
> if (err)
> goto err_unpin_maps;
>
> I have the same attitude towards this patch as the first one in the
> series: not worth it. Nothing is currently broken, the code as is relatively
> readable, this version is not much simpler, it just looks slightly different
> taste-wise..
>
It's a minor improvement, IMO, so I don't mind it (5 repetitions of
annoying error case handling seems worth streamlining). But selftests
just for this seems like an overkill.
> How about this: if you really want to push this kind of cleanup, send
> selftests that exercise all these error cases? :-)
>
>
[...]
