[PATCH 02/28] perf config: Honour $PERF_CONFIG env var to specify alternate .perfconfig

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

We had this comment in Documentation/perf_counter/config.c, i.e. since
when we got this from the git sources, but never really did that
getenv("PERF_CONFIG"), do it now as I need to disable whatever
~/.perfconfig root has so that tests parsing tool output are done for
the expected default output or that we specify an alternate config file
that when read will make the tools produce expected output.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Taeung Song <treeze.taeung@gmail.com>
Fixes: 078006012401 ("perf_counter tools: add in basic glue from Git")
Link: https://lkml.kernel.org/n/tip-jo209zac9rut0dz1rqvbdlgm@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/perf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 97e2628ea5dd..d4e4d53e8b44 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -441,6 +441,9 @@ int main(int argc, const char **argv)
 
 	srandom(time(NULL));
 
+	/* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
+	config_exclusive_filename = getenv("PERF_CONFIG");
+
 	err = perf_config(perf_default_config, NULL);
 	if (err)
 		return err;
-- 
2.21.0