netdev - Re: [PATCH bpf-next v2 0/3] bpftool: match programs and maps by names

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Message-ID: <20191215174004.57deg3fs7665jokd@ast-mbp.dhcp.thefacebook.com>
Date:   Sun, 15 Dec 2019 09:40:05 -0800
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Paul Chaignon <paul.chaignon@...nge.com>
Cc:     bpf@...r.kernel.org, Quentin Monnet <quentin.monnet@...ronome.com>,
        paul.chaignon@...il.com, netdev@...r.kernel.org,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Andrii Nakryiko <andriin@...com>
Subject: Re: [PATCH bpf-next v2 0/3] bpftool: match programs and maps by names

On Fri, Dec 13, 2019 at 08:09:52PM +0100, Paul Chaignon wrote:
> When working with frequently modified BPF programs, both the ID and the
> tag may change.  bpftool currently doesn't provide a "stable" way to match
> such programs.  This patchset allows bpftool to match programs and maps by
> name.
> 
> When given a tag that matches several programs, bpftool currently only
> considers the first match.  The first patch changes that behavior to
> either process all matching programs (for the show and dump commands) or
> error out.  The second patch implements program lookup by name, with the
> same behavior as for tags in case of ambiguity.  The last patch implements
> map lookup by name.
> 
> Changelogs:
>   Changes in v2:
>     - Fix buffer overflow after realloc.
>     - Add example output to commit message.
>     - Properly close JSON arrays on errors.
>     - Fix style errors (line breaks, for loops, exit labels, type for
>       tagname).
>     - Move do_show code for argc == 2 to do_show_subset functions.
>     - Rebase.

Loogs good. Applied.

I found the exact match logic unintuitive though.
Since 'prog show' can print multiple may be allow partial match on name?
So 'bpftool p s name tracepoint__' would print all BCC-based programs
that attach to tracepoints.
It would be roughly equivalent to 'bpftool p s |grep tracepoint__',
but grep captures single line.
There is 'bpftool perf|grep tracepoint' as well, but since the tool
matches on name it probably should match partial name too.