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Date: Wed,  1 May 2024 21:01:11 -0700
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Subject: [PATCH v4 5/6] perf test pmu: Test all sysfs PMU event names are the
 same case
From: Ian Rogers <irogers@google.com>
To: Kan Liang <kan.liang@linux.intel.com>, Thomas Richter <tmricht@linux.ibm.com>, 
	Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, 
	Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@kernel.org>, 
	Bjorn Helgaas <bhelgaas@google.com>, Jonathan Corbet <corbet@lwn.net>, 
	Randy Dunlap <rdunlap@infradead.org>, Jing Zhang <renyu.zj@linux.alibaba.com>, 
	James Clark <james.clark@arm.com>, Ravi Bangoria <ravi.bangoria@amd.com>, 
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Cc: Ian Rogers <irogers@google.com>
Content-Type: text/plain; charset="UTF-8"

Being either lower or upper case means event name probes can avoid
scanning the directory doing case insensitive comparisons, just the
lower or upper case version of the name can be checked for
existence. For the majority of PMUs event names are all lower case,
upper case names are present on S390.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/pmu.c | 90 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/tools/perf/tests/pmu.c b/tools/perf/tests/pmu.c
index 6e18a4c447ce..bcbe58fb7d66 100644
--- a/tools/perf/tests/pmu.c
+++ b/tools/perf/tests/pmu.c
@@ -5,12 +5,17 @@
 #include "pmu.h"
 #include "tests.h"
 #include "debug.h"
+#include "fncache.h"
+#include <api/fs/fs.h>
+#include <ctype.h>
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 
 /* Fake PMUs created in temp directory. */
 static LIST_HEAD(test_pmus);
@@ -252,9 +257,94 @@ static int test__pmu_events(struct test_suite *test __maybe_unused, int subtest
 	return ret;
 }
 
+static bool permitted_event_name(const char *name)
+{
+	bool has_lower = false, has_upper = false;
+
+	for (size_t i = 0; i < strlen(name); i++) {
+		char c = name[i];
+
+		if (islower(c)) {
+			if (has_upper)
+				return false;
+			has_lower = true;
+			continue;
+		}
+		if (isupper(c)) {
+			if (has_lower)
+				return false;
+			has_upper = true;
+			continue;
+		}
+		if (!isdigit(c) && c != '.' && c != '_' && c != '-')
+			return false;
+	}
+	return true;
+}
+
+static int test__pmu_event_names(struct test_suite *test __maybe_unused,
+				 int subtest __maybe_unused)
+{
+	char path[PATH_MAX];
+	DIR *pmu_dir, *event_dir;
+	struct dirent *pmu_dent, *event_dent;
+	const char *sysfs = sysfs__mountpoint();
+	int ret = TEST_OK;
+
+	if (!sysfs) {
+		pr_err("Sysfs not mounted\n");
+		return TEST_FAIL;
+	}
+
+	snprintf(path, sizeof(path), "%s/bus/event_source/devices/", sysfs);
+	pmu_dir = opendir(path);
+	if (!pmu_dir) {
+		pr_err("Error opening \"%s\"\n", path);
+		return TEST_FAIL;
+	}
+	while ((pmu_dent = readdir(pmu_dir))) {
+		if (!strcmp(pmu_dent->d_name, ".") ||
+		    !strcmp(pmu_dent->d_name, ".."))
+			continue;
+
+		snprintf(path, sizeof(path), "%s/bus/event_source/devices/%s/type",
+			 sysfs, pmu_dent->d_name);
+
+		/* Does it look like a PMU? */
+		if (!file_available(path))
+			continue;
+
+		/* Process events. */
+		snprintf(path, sizeof(path), "%s/bus/event_source/devices/%s/events",
+			 sysfs, pmu_dent->d_name);
+
+		event_dir = opendir(path);
+		if (!event_dir) {
+			pr_debug("Skipping as no event directory \"%s\"\n", path);
+			continue;
+		}
+		while ((event_dent = readdir(event_dir))) {
+			const char *event_name = event_dent->d_name;
+
+			if (!strcmp(event_name, ".") || !strcmp(event_name, ".."))
+				continue;
+
+			if (!permitted_event_name(event_name)) {
+				pr_err("Invalid sysfs event name: %s/%s\n",
+					pmu_dent->d_name, event_name);
+				ret = TEST_FAIL;
+			}
+		}
+		closedir(event_dir);
+	}
+	closedir(pmu_dir);
+	return ret;
+}
+
 static struct test_case tests__pmu[] = {
 	TEST_CASE("Parsing with PMU format directory", pmu_format),
 	TEST_CASE("Parsing with PMU event", pmu_events),
+	TEST_CASE("PMU event names", pmu_event_names),
 	{	.name = NULL, }
 };
 
-- 
2.45.0.rc0.197.gbae5840b3b-goog