1 files changed, 71 insertions, 0 deletions
diff --git a/tools/testing/selftests/sched_ext/util.c b/tools/testing/selftests/sched_ext/util.c
new file mode 100644
index 000000000000..e47769c91918
--- /dev/null
+++ b/tools/testing/selftests/sched_ext/util.c
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2024 David Vernet <dvernet@meta.com>
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Returns read len on success, or -errno on failure. */
+static ssize_t read_text(const char *path, char *buf, size_t max_len)
+{
+	ssize_t len;
+	int fd;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return -errno;
+
+	len = read(fd, buf, max_len - 1);
+
+	if (len >= 0)
+		buf[len] = 0;
+
+	close(fd);
+	return len < 0 ? -errno : len;
+}
+
+/* Returns written len on success, or -errno on failure. */
+static ssize_t write_text(const char *path, char *buf, ssize_t len)
+{
+	int fd;
+	ssize_t written;
+
+	fd = open(path, O_WRONLY | O_APPEND);
+	if (fd < 0)
+		return -errno;
+
+	written = write(fd, buf, len);
+	close(fd);
+	return written < 0 ? -errno : written;
+}
+
+long file_read_long(const char *path)
+{
+	char buf[128];
+
+
+	if (read_text(path, buf, sizeof(buf)) <= 0)
+		return -1;
+
+	return atol(buf);
+}
+
+int file_write_long(const char *path, long val)
+{
+	char buf[64];
+	int ret;
+
+	ret = sprintf(buf, "%lu", val);
+	if (ret < 0)
+		return ret;
+
+	if (write_text(path, buf, sizeof(buf)) <= 0)
+		return -1;
+
+	return 0;
+}