On Sun, Dec 15, 2019 at 09:40:05AM -0800, Alexei Starovoitov wrote: > 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. I had a look at bcc and it actually removes these prefixes from the program's name (except for kretprobes, but it looks like an oversight). I still agree a partial match would be good to have since related programs are more likely to share prefixes (e.g., func_entry and func_exit). Maybe matching on prefixes would be enough though? I can't think of use cases for a true partial match and the behavior might be a bit unexpected for users... Or we go all the way and implement support for * (e.g., tcp_* for all bcc kprobes on tcp functions; *tcp* for all programs containing 'tcp'). > There is 'bpftool perf|grep tracepoint' as well, but since the tool > matches on name it probably should match partial name too. >
