On Wed, Dec 13, 2023 at 02:23:26PM -0800, Andrii Nakryiko wrote:
> Besides already supported special "any" value and hex bit mask, support
> string-based parsing of delegation masks based on exact enumerator
> names. Utilize BTF information of `enum bpf_cmd`, `enum bpf_map_type`,
> `enum bpf_prog_type`, and `enum bpf_attach_type` types to find supported
> symbolic names (ignoring __MAX_xxx guard values). So "BPF_PROG_LOAD" and
> "BPF_MAP_CREATE" are valid values to specify for delegate_cmds options,
> "BPF_MAP_TYPE_ARRAY" is among supported for map types, etc.
>
> Besides supporting string values, we also support multiple values
> specified at the same time, using colon (':') separator.
>
> There are corresponding changes on bpf_show_options side to use known
> values to print them in human-readable format, falling back to hex mask
> printing, if there are any unrecognized bits. This shouldn't be
> necessary when enum BTF information is present, but in general we should
> always be able to fall back to this even if kernel was built without BTF.
>
> Example below shows various ways to specify delegate_cmds options
> through mount command and how mount options are printed back:
>
> $ sudo mkdir -p /sys/fs/bpf/token
> $ sudo mount -t bpf bpffs /sys/fs/bpf/token \
> -o delegate_cmds=BPF_PROG_LOAD \
> -o delegate_cmds=BPF_MAP_CREATE \
> -o delegate_cmds=BPF_TOKEN_CREATE:BPF_BTF_LOAD:BPF_LINK_CREATE
> $ mount | grep token
> bpffs on /sys/fs/bpf/token type bpf (rw,relatime,delegate_cmds=BPF_MAP_CREATE:BPF_PROG_LOAD:BPF_BTF_LOAD:BPF_LINK_CREATE:BPF_TOKEN_CREATE)
imo this is too verbose.
For cmds it doesn't look as bad. "BPF_" prefix is repetitive, but not overly so.
But for maps and progs it will be bad.
It will look like:
delegate_progs=BPF_PROG_TYPE_SOCKET_FILTER:BPF_PROG_TYPE_SOCKET_XDP:BPF_PROG_TYPE_SCHED_CLS
which is not readable.
delegate_progs=SOCKET_FILTER:XDP:SCHED_CLS
is much better.
And I would go further (like libbpf does) and lower case them for output
while allow both upper and lower for input:
delegate_progs=socket_filter:xdp:sched_cls.
Because of stripping the prefix for maps and progs I would strip the prefix for cmds too
for consistency.
pw-bot: cr
