incubator-nuttx/include/nuttx/fs/procfs.h

189 lines
7.3 KiB
C

/****************************************************************************
* include/nuttx/fs/procfs.h
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Ken Pettit <pettitkd@gmail.com>
*
* 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 NuttX 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 OWNER 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 __INCLUDE_NUTTX_FS_PROCFS_H
#define __INCLUDE_NUTTX_FS_PROCFS_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/fs/fs.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Data entry declaration prototypes ****************************************/
/* Procfs operations are a subset of the mountpt_operations */
struct procfs_operations
{
/* The procfs open method differs from the driver open method
* because it receives (1) the inode that contains the procfs
* private data, (2) the relative path into the procfs, and (3)
* information to manage privileges.
*/
int (*open)(FAR struct file *filep, FAR const char *relpath,
int oflags, mode_t mode);
/* The following methods must be identical in signature and position because
* the struct file_operations and struct mountp_operations are treated like
* unions.
*/
int (*close)(FAR struct file *filep);
ssize_t (*read)(FAR struct file *filep, FAR char *buffer, size_t buflen);
ssize_t (*write)(FAR struct file *filep, FAR const char *buffer, size_t buflen);
/* The two structures need not be common after this point. The following
* are extended methods needed to deal with the unique needs of mounted
* file systems.
*
* Additional open-file-specific procfs operations:
*/
int (*dup)(FAR const struct file *oldp, FAR struct file *newp);
/* Directory operations */
int (*opendir)(FAR const char *relpath, FAR struct fs_dirent_s *dir);
int (*closedir)(FAR struct fs_dirent_s *dir);
int (*readdir)(FAR struct fs_dirent_s *dir);
int (*rewinddir)(FAR struct fs_dirent_s *dir);
/* Operations on paths */
int (*stat)(FAR const char *relpath, FAR struct stat *buf);
};
/* Procfs handler prototypes ************************************************/
/* This is a procfs entry that each handler should provide to supply
* specific operations for file and directory handling.
*/
struct procfs_entry_s
{
FAR const char *pathpattern;
FAR const struct procfs_operations *ops;
};
/* Specifies the common elements for an open file in the procfs
* file system. This structure should be sub-classed by handlers
* to add their own specific data elements to the context.
*/
struct procfs_file_s
{
FAR const struct procfs_entry_s *procfsentry;
};
/* The generic proc/ pseudo directory structure */
struct procfs_dir_priv_s
{
uint8_t level; /* Directory level. Currently 0 or 1 */
uint16_t index; /* Index to the next directory entry */
uint16_t nentries; /* Number of directory entries */
FAR const struct procfs_entry_s *procfsentry; /* Pointer to procfs handler entry */
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Name: procfs_memcpy
*
* Description:
* procfs/ file data may be read by the user with different user buffer
* sizes to receive the data. If the amount of data to be returned is
* large or if the callers receive buffer is small, then multiple read
* operations will be required.
*
* If multiple read operations are required, then each read operation will
* be identical accept that file position (f_pos) will be incremented with
* each read: f_pos must be incremented by the read method after each
* read operation to provide the 'offset' for the next read.
*
* procfs_memcpy() is a helper function. Each read() method should
* provide data in a local data buffer ('src' and 'srclen'). This
* will transfer the data to the user receive buffer ('dest' and 'destlen'),
* respecting both (1) the size of the destination buffer so that it will
* write beyond the user receiver and (1) the file position, 'offset'.
*
* This function will skip over data until the under of bytes specified
* by 'offset' have been skipped. Then it will transfer data from the
* the procfs/ 'src' buffer into the user receive buffer. No more than
* 'destlen' bytes will be transferred.
*
* Input Parameters:
* src - The address of the intermediate procfs/ buffer containing the
* data to be returned.
* srclen - The number of bytes of data in the 'src' buffer
* dest - The address of the user's receive buffer.
* destlen - The size (in bytes) of the user's receive buffer.
* offset - On input, this is the number of bytes to skip before returning
* data; If bytes were skipped, this offset will be decremented.
* Data will not be transferred until this offset decrements to
* zero.
*
* Returned Value:
* The number of bytes actually transferred into the user's receive buffer.
*
****************************************************************************/
size_t procfs_memcpy(FAR const char *src, size_t srclen,
FAR char *dest, size_t destlen,
off_t *offset);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* __INCLUDE_NUTTX_FS_PROCFS_H */