commit 01f4ad74ce79cd9a72c7ad4cb312be7de4be2b9a
author Ryan Savitski <rsavitski@google.com> Mon Apr 04 13:17:29 2022 +0100
committer Ryan Savitski <rsavitski@google.com> Mon Apr 04 13:17:29 2022 +0100
tree a24c1b034ef6f3f9191ce3a827a54145db7c3147
parent 006d75d219745f48dd0b8e3f490c0a352ca0e79f

traced_perf: support wildcards in /proc/pid/cmdline matching

This changes the semantics of the |target_cmdline| and |exclude_cmdline|
config fields. Normally we should've introduced a separate proto field
for this, but the change is compatible with vast majority of existing
configs, so it's less hassle for both us and users to reuse the field.
See go/perfetto-profiler-globs.

There are two compatibility cases to consider:
(a) old config expecting canonicalization + new profiler binary
(b) new config with a wildcard + old profiler binary

For (a), the primary difference is how a pattern with a fully qualified
path is treated. "/bin/echo" would previously canonicalize to "echo",
and match against anything with that suffix in argv0. Now we'll match
only against that particular fully qualified path. For (b), the old
implementation will try to do exact string comparisons, so patterns with
wildcards will effectively match nothing.

Configs that want to remain compatible with both versions of the
profiler can specify several versions of the same target_cmdline, as the
field is repeated. It'll potentially match more than before, but only in
corner cases.

Bug: 201273553
Change-Id: I48991992fb9456cfe11cab7ac7a92d7fff4ac71c