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From: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
To: reinette.chatre@intel.com,
	shuah@kernel.org,
	fenghua.yu@intel.com
Cc: linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	ilpo.jarvinen@linux.intel.com
Subject: [PATCH v5 4/5] selftests/resctrl: Add resource_info_file_exists()
Date: Fri,  9 Feb 2024 15:02:01 +0100
Message-ID: <a2cc9ebaa216f7cc0782c2f112ce79bdd5ba2205.1707487039.git.maciej.wieczor-retman@intel.com>
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Feature checking done by resctrl_mon_feature_exists() covers features
represented by the feature name presence inside the 'mon_features' file
in /sys/fs/resctrl/info/L3_MON directory. There exists a different way
to represent feature support and that is by the presence of 0 or 1 in a
single file in the info/resource directory. In this case the filename
represents what feature support is being indicated.

Add a generic function to check file presence in the
/sys/fs/resctrl/info/<RESOURCE> directory.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
Changelog v5:
- feature -> file. (Reinette)
- Redo return description and path in the comment. (Reinette)

Changelog v4:
- Remove unnecessary new lines.
- Change 'feature' -> 'file' to keep things generic. (Reinette)
- Add Ilpo's reviewed-by tag.

Changelog v3:
- Split off the new function into this patch. (Reinette)

Changelog v2:
- Add this patch.

 tools/testing/selftests/resctrl/resctrlfs.c | 25 +++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index af4f800ab23d..0e930fc06ab5 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -764,6 +764,31 @@ bool resctrl_mon_feature_exists(const char *resource, const char *feature)
 	return !!res;
 }
 
+/*
+ * resource_info_file_exists - Check if a file is present inside
+ * /sys/fs/resctrl/info/@resource.
+ * @resource:	Required resource (Eg: MB, L3, L2, etc.)
+ * @file:	Required file.
+ *
+ * Return: True if the /sys/fs/resctrl/info/@resource/@file exists, else false.
+ */
+bool resource_info_file_exists(const char *resource, const char *file)
+{
+	char res_path[PATH_MAX];
+	struct stat statbuf;
+
+	if (!file || !resource)
+		return false;
+
+	snprintf(res_path, sizeof(res_path), "%s/%s/%s", INFO_PATH, resource,
+		 file);
+
+	if (stat(res_path, &statbuf))
+		return false;
+
+	return true;
+}
+
 bool test_resource_feature_check(const struct resctrl_test *test)
 {
 	return resctrl_resource_exists(test->resource);
-- 
2.43.0