bpftool output is not user friendly when dumping a map with only a few
populated entries:
$ bpftool map
1: devmap name tx_devmap flags 0x0
key 4B value 4B max_entries 64 memlock 4096B
2: array name tx_idxmap flags 0x0
key 4B value 4B max_entries 64 memlock 4096B
$ bpftool map dump id 1
key:
00 00 00 00
value:
No such file or directory
key:
01 00 00 00
value:
No such file or directory
key:
02 00 00 00
value:
No such file or directory
key: 03 00 00 00 value: 03 00 00 00
Handle ENOENT by keeping the line format sane and dumping
"<no entry>" for the value
$ bpftool map dump id 1
key: 00 00 00 00 value: <no entry>
key: 01 00 00 00 value: <no entry>
key: 02 00 00 00 value: <no entry>
key: 03 00 00 00 value: 03 00 00 00
...
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
bf598a8f0f