proc_file.h

/*
 * Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
 * Copyright (c) 2020-2021 Huawei Device Co., Ltd. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
 *    of conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef PROC_FILE_H
#define PROC_FILE_H

#include "proc_fs.h"

/**
 * @ingroup  procfs
 * @brief open a proc node
 *
 * @par Description:
 * This API is used to open the  node by 'fileName' and flags,
 *
 * @attention
 * <ul>
 * <li>None.</li>
 * </ul>
 *
 * @param  fileName [IN] Type  #const char * the fileName of the node to  be opened
 * @param  flags    [IN] Type  #int the flags of open's node
 *
 * @retval #NULL                open failed
 * @retval #NOT NULL            open successfully
 * @par Dependency:
 * <ul><li>proc_fs.h: the header file that contains the API declaration.</li></ul>
 * @see proc_close
 *
 */
extern struct ProcDirEntry *OpenProcFile(const char *fileName, int flags, ...);

/**
 * @ingroup  procfs
 * @brief read a proc node
 *
 * @par Description:
 * This API is used to read the node by pde
 *
 * @attention
 * <ul>
 * <li>None.</li>
 * </ul>
 *
 * @param  pde     [IN] Type #struct ProcDirEntry * pointer of the node structure to be read
 * @param  buf     [IN] Type #void *  user-provided to save the data
 * @param  len     [IN] Type #size_t  the length of want to read
 *
 * @retval #-1                read failed
 * @retval #>0                Number of bytes read success
 * @par Dependency:
 * <ul><li>proc_fs.h: the header file that contains the API declaration.</li></ul>
 * @see proc_open
 *
 */
extern int ReadProcFile(struct ProcDirEntry *pde, void *buf, size_t len);

/**
 * @ingroup  procfs
 * @brief write a proc node
 *
 * @par Description:
 * This API is used to write the node by pde
 *
 * @attention
 * <ul>
 * <li>None.</li>
 * </ul>
 *
 * @param  pde     [IN] Type #struct ProcDirEntry * pointer of the node structure to be written
 * @param  buf     [IN] Type #const void *    data to write
 * @param  len     [IN] Type #size_t    length of data to write
 *
 * @retval #-1                write failed
 * @retval #>0                Number of bytes write successfully
 * @par Dependency:
 * <ul><li>proc_fs.h: the header file that contains the API declaration.</li></ul>
 * @see proc_open
 *
 */
extern int WriteProcFile(struct ProcDirEntry *pde, const void *buf, size_t len);

/**
 * @ingroup  procfs
 * @brief File migration
 *
 * @par Description:
 * This API is used to set the proc file migration
 *
 * @attention
 * <ul>
 * <li>None.</li>
 * </ul>
 *
 * @param  pde     [IN] Type #struct ProcDirEntry *   pointer of the node structure to be deviation
 * @param  offset  [IN] Type #loff_t    the number of deviation
 * @param  whence  [IN] Type #int       the begin of  deviation
 *
 * @retval #<0                deviation failed
 * @retval #>=0               deviation successfully
 * @par Dependency:
 * <ul><li>proc_fs.h: the header file that contains the API declaration.</li></ul>
 * @see proc_open
 *
 */
extern loff_t LseekProcFile(struct ProcDirEntry *pde, loff_t offset, int whence);

/**
 * @ingroup  procfs
 * @brief directory migration
 *
 * @par Description:
 * This API is used to set the proc directory migration
 *
 * @attention
 * <ul>
 * <li>Only allow SEEK_SET to zero.</li>
 * </ul>
 *
 * @param  pde     [IN] Type #struct ProcDirEntry *   pointer of the node structure to be deviated
 * @param  pos     [IN] Type #off_t *      the number of deviation
 * @param  whence  [IN] Type #int       the begin of deviation
 *
 * @retval #EINVAL            deviation failed
 * @retval #ENOERR            deviation successfully
 * @par Dependency:
 * <ul><li>proc_fs.h: the header file that contains the API declaration.</li></ul>
 * @see proc_open
 *
 */
int LseekDirProcFile(struct ProcDirEntry *pde, off_t *pos, int whence);

/**
 * @ingroup  procfs
 * @brief close a proc node
 *
 * @par Description:
 * This API is used to close the node by pde
 *
 * @attention
 * <ul>
 * <li>None.</li>
 * </ul>
 *
 * @param  pde [IN] Type #struct ProcDirEntry * pointer of the node structure to be closed
 *
 * @retval #-1                close failed
 * @retval #0                 close successfully
 * @par Dependency:
 * <ul><li>proc_fs.h: the header file that contains the API declaration.</li></ul>
 * @see proc_open
 *
 */
extern int CloseProcFile(struct ProcDirEntry *pde);

extern struct ProcDirEntry *GetProcRootEntry(void);
extern int ProcOpen(struct ProcFile *procFile);

#endif