bpftool: Improve handling of ENOSPC on reuseport_array map dumps
avoids outputting a series of
value:
No space left on device
The value itself is not wrong but bpf_fd_reuseport_array_lookup_elem() can
only return it if the map was created with value_size = 8. There's nothing
bpftool can do about it. Instead of repeating this error for every key in
the map, print an explanatory warning and a specialized error.
example before:
key: 00 00 00 00
value:
No space left on device
key: 01 00 00 00
value:
No space left on device
key: 02 00 00 00
value:
No space left on device
Found 0 elements
example after:
Warning: cannot read values from reuseport_sockarray map with value_size != 8
key: 00 00 00 00 value: <cannot read>
key: 01 00 00 00 value: <cannot read>
key: 02 00 00 00 value: <cannot read>
Found 0 elements
Signed-off-by: Benjamin Poirier <bpoirier@suse.com> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>