qcacmn: Add qdf_file and qdf_parse files to QDF

Add an QDF abstraction for reading a file. Also, add the first consumer,
qdf_ini_parse(), as well. This is pure parsing logic, which offloads the
actual content handling to the caller via callback functions.

Change-Id: Idfca74c5543a5b0da7ddd1bdc6e2ad2be59ed36b
CRs-Fixed: 2184463

qdf/inc/qdf_file.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2018 The Linux Foundation. All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for
+ * any purpose with or without fee is hereby granted, provided that the
+ * above copyright notice and this permission notice appear in all
+ * copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+ * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/**
+ * DOC: Thin filesystem API abstractions
+ */
+
+#ifndef __QDF_FILE_H
+#define __QDF_FILE_H
+
+#include "qdf_status.h"
+
+/**
+ * qdf_file_read() - read the entire contents of a file
+ * @path: the full path of the file to read
+ * @out_buf: double pointer for referring to the file contents buffer
+ *
+ * This API allocates a new, null-terminated buffer containing the contents of
+ * the file at @path. On success, @out_buf points to this new buffer, otherwise
+ * @out_buf is set to NULL.
+ *
+ * Consumers must free the allocated buffer by calling qdf_file_buf_free().
+ *
+ * Return: QDF_STATUS
+ */
+QDF_STATUS qdf_file_read(const char *path, char **out_buf);
+
+/**
+ * qdf_file_buf_free() - free a previously allocated file buffer
+ * @file_buf: pointer to the file buffer to free
+ *
+ * This API is used in conjunction with qdf_file_read().
+ *
+ * Return: None
+ */
+void qdf_file_buf_free(char *file_buf);
+
+#endif /* __QDF_FILE_H */
+