[PATCH i-g-t v4 03/41] lib/vkms: Allow to enable/disable VKMS devices

[José Expósito]

Add helper to enable, disable and check the enabled status of a VKMS
device and add a test to ensure that the default value is correctly set.

Reviewed-by: Louis Chauvet <louis.chauvet at bootlin.com>
Signed-off-by: José Expósito <jose.exposito89 at gmail.com>
---
 lib/igt_vkms.c             | 98 ++++++++++++++++++++++++++++++++++++++
 lib/igt_vkms.h             |  7 +++
 tests/vkms/vkms_configfs.c | 18 +++++++
 3 files changed, 123 insertions(+)

diff --git a/lib/igt_vkms.c b/lib/igt_vkms.c
index 03931d2e4..7d3575ca0 100644
--- a/lib/igt_vkms.c
+++ b/lib/igt_vkms.c
@@ -7,15 +7,21 @@
 
 #include <dirent.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <ftw.h>
 #include <limits.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "igt.h"
 #include "igt_vkms.h"
 
 #define VKMS_ROOT_DIR_NAME		"vkms"
+#define VKMS_FILE_ENABLED		"enabled"
 
 /**
  * SECTION:igt_vkms
@@ -46,6 +52,50 @@ static const char *mount_vkms_configfs(void)
 	return vkms_root_path;
 }
 
+static int read_int(const char *path)
+{
+	FILE *file;
+	int value;
+	int ret;
+
+	file = fopen(path, "r");
+	igt_assert_f(file, "Error opening '%s'\n", path);
+
+	ret = fscanf(file, "%d", &value);
+	fclose(file);
+	igt_assert_f(ret == 1, "Error reading integer from '%s'\n", path);
+
+	return value;
+}
+
+static bool read_bool(const char *path)
+{
+	int ret;
+
+	ret = read_int(path);
+
+	return !!ret;
+}
+
+static void write_int(const char *path, int value)
+{
+	FILE *file;
+	int ret;
+
+	file = fopen(path, "w");
+	igt_assert_f(file, "Error opening '%s'\n", path);
+
+	ret = fprintf(file, "%d", value);
+	igt_assert_f(ret >= 0, "Error writing to '%s'\n", path);
+
+	fclose(file);
+}
+
+static void write_bool(const char *path, bool value)
+{
+	write_int(path, value ? 1 : 0);
+}
+
 /**
  * igt_require_vkms_configfs:
  *
@@ -64,6 +114,22 @@ void igt_require_vkms_configfs(void)
 		closedir(dir);
 }
 
+/**
+ * igt_vkms_get_device_enabled_path:
+ * @dev: Device to get the enabled path from
+ * @path: Output path
+ * @len: Maximum @path length
+ *
+ * Returns the device "enabled" file path.
+ */
+void igt_vkms_get_device_enabled_path(igt_vkms_t *dev, char *path, size_t len)
+{
+	int ret;
+
+	ret = snprintf(path, len, "%s/%s", dev->path, VKMS_FILE_ENABLED);
+	igt_assert(ret >= 0 && ret < len);
+}
+
 /**
  * igt_vkms_device_create:
  * @name: VKMS device name
@@ -166,6 +232,8 @@ void igt_vkms_device_destroy(igt_vkms_t *dev)
 
 	igt_assert(dev);
 
+	igt_vkms_device_set_enabled(dev, false);
+
 	ret = remove_device_dir(dev);
 	igt_assert_f(ret == 0,
 		     "Unable to rmdir device directory '%s'. Got errno=%d (%s)\n",
@@ -204,3 +272,33 @@ void igt_vkms_destroy_all_devices(void)
 
 	closedir(dir);
 }
+
+/**
+ * igt_vkms_device_is_enabled:
+ * @dev: The device to check
+ *
+ * Indicate whether a VKMS device is enabled or not.
+ */
+bool igt_vkms_device_is_enabled(igt_vkms_t *dev)
+{
+	char path[PATH_MAX];
+
+	igt_vkms_get_device_enabled_path(dev, path, sizeof(path));
+
+	return read_bool(path);
+}
+
+/**
+ * igt_vkms_device_set_enabled:
+ * @dev: Device to enable or disable
+ *
+ * Enable or disable a VKMS device.
+ */
+void igt_vkms_device_set_enabled(igt_vkms_t *dev, bool enabled)
+{
+	char path[PATH_MAX];
+
+	igt_vkms_get_device_enabled_path(dev, path, sizeof(path));
+
+	write_bool(path, enabled);
+}
diff --git a/lib/igt_vkms.h b/lib/igt_vkms.h
index 95d7a53cd..8b3595b00 100644
--- a/lib/igt_vkms.h
+++ b/lib/igt_vkms.h
@@ -8,6 +8,8 @@
 #ifndef __IGT_VKMS_H__
 #define __IGT_VKMS_H__
 
+#include <stdbool.h>
+
 /**
  * igt_vkms_t:
  * @path: VKMS root directory inside configfs mounted directory
@@ -20,8 +22,13 @@ typedef struct igt_vkms {
 
 void igt_require_vkms_configfs(void);
 
+void igt_vkms_get_device_enabled_path(igt_vkms_t *dev, char *path, size_t len);
+
 igt_vkms_t *igt_vkms_device_create(const char *name);
 void igt_vkms_device_destroy(igt_vkms_t *dev);
 void igt_vkms_destroy_all_devices(void);
 
+bool igt_vkms_device_is_enabled(igt_vkms_t *dev);
+void igt_vkms_device_set_enabled(igt_vkms_t *dev, bool enabled);
+
 #endif /* __IGT_VKMS_H__ */
diff --git a/tests/vkms/vkms_configfs.c b/tests/vkms/vkms_configfs.c
index f659a7a22..0ed6a63a6 100644
--- a/tests/vkms/vkms_configfs.c
+++ b/tests/vkms/vkms_configfs.c
@@ -102,6 +102,23 @@ static void test_device_default_files(void)
 	igt_vkms_device_destroy(dev);
 }
 
+/**
+ * SUBTEST: device-default-values
+ * Description: Check that the default values for the device are correct.
+ */
+
+static void test_device_default_values(void)
+{
+	igt_vkms_t *dev;
+
+	dev = igt_vkms_device_create(__func__);
+	igt_assert(dev);
+
+	igt_assert(!igt_vkms_device_is_enabled(dev));
+
+	igt_vkms_device_destroy(dev);
+}
+
 igt_main
 {
 	struct {
@@ -109,6 +126,7 @@ igt_main
 		void (*fn)(void);
 	} tests[] = {
 		{ "device-default-files", test_device_default_files },
+		{ "device-default-values", test_device_default_values },
 	};
 
 	igt_fixture {
-- 
2.50.1