diff options
| author | Ian Rogers <irogers@google.com> | 2024-08-06 15:06:14 -0700 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2024-08-20 17:53:12 -0300 |
| commit | e25ebda78e230283bf707ae3e9655270ff40a7f9 (patch) | |
| tree | 74d714be33a29f0e33bdfcc9f9030207d972318e /tools/perf/util/util.c | |
| parent | 8b1042c425f6a5a9fb57c5e1d5ecf5247cf899a6 (diff) | |
perf cap: Tidy up and improve capability testing
Remove dependence on libcap. libcap is only used to query whether a
capability is supported, which is just 1 capget system call.
If the capget system call fails, fall back on root permission
checking. Previously if libcap fails then the permission is assumed
not present which may be pessimistic/wrong.
Add a used_root out argument to perf_cap__capable to say whether the
fall back root check was used. This allows the correct error message,
"root" vs "users with the CAP_PERFMON or CAP_SYS_ADMIN capability", to
be selected.
Tidy uses of perf_cap__capable so that tests aren't repeated if capget
isn't supported.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240806220614.831914-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/util.c')
| -rw-r--r-- | tools/perf/util/util.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index 4f561e5e4162..9d55a13787ce 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -325,9 +325,15 @@ int perf_event_paranoid(void) bool perf_event_paranoid_check(int max_level) { - return perf_cap__capable(CAP_SYS_ADMIN) || - perf_cap__capable(CAP_PERFMON) || - perf_event_paranoid() <= max_level; + bool used_root; + + if (perf_cap__capable(CAP_SYS_ADMIN, &used_root)) + return true; + + if (!used_root && perf_cap__capable(CAP_PERFMON, &used_root)) + return true; + + return perf_event_paranoid() <= max_level; } static int |