On 2015/10/17 18:48, Wang Nan wrote:
> bpf__config_obj() is introduced as a core API to config BPF object
> after loading. One configuration option of maps is introduced. After
> this patch BPF object can accept configuration like:
>
> maps.my_map.value=1234
There's an inconvience in this syntax.
In following cmdline:
# perf record -e mybpf.c/maps.channel.value=1234/ ls
because of the greedy manner of flex, mybpf.c/maps.c would
be expressed as path of a BPF source file (and yes, it is a valid
path).
If flex has a non-greedy mode then it would be fixed easily. However,
the official flex docs reveals its policy that it doesn't and would not
provide non-greedy matching. Even if we have non-greedy matching,
we are unable to prohibit user to put their BPF object into path
like
/home/user/mybpf.c/thefile.c
Fortunately this patch has not beed merged, so we have a chance to fix
it at very beginning. I will replace all '.' in object config string
to ':', so the above cmdline becomes:
# perf record -e mybpf.c/maps:channel:value=1234/ ls
[1]
http://flex.sourceforge.net/manual/Why-doesn_0027t-flex-have-non_002dgreedy-operators-like-perl-does_003f.html