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incubator-nuttx/include/nuttx/fs.h

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/****************************************************************************
* include/nuttx/fs.h
*
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 __NUTTX_FS_H
#define __NUTTX_FS_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <semaphore.h>
#include <nuttx/compiler.h>
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Type Definitions
****************************************************************************/
/* This structure is provided by devices when they are registered with the
* system. It is used to call back to perform device specific operations.
*/
struct file;
struct pollfd;
struct file_operations
{
/* The device driver open method differs from the mountpoint open method */
int (*open)(FAR struct file *filp);
/* 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 *filp);
ssize_t (*read)(FAR struct file *filp, FAR char *buffer, size_t buflen);
ssize_t (*write)(FAR struct file *filp, FAR const char *buffer, size_t buflen);
off_t (*seek)(FAR struct file *filp, off_t offset, int whence);
int (*ioctl)(FAR struct file *filp, int cmd, unsigned long arg);
#ifndef CONFIG_DISABLE_POLL
int (*poll)(FAR struct file *filp, struct pollfd *fds, boolean setup);
#endif
/* The two structures need not be common after this point */
};
/* This structure provides information about the state of a block driver */
#ifndef CONFIG_DISABLE_MOUNTPOUNT
struct geometry
{
boolean geo_available; /* TRUE: The device is vailable */
boolean geo_mediachanged; /* TRUE: The media has changed since last query */
boolean geo_writeenabled; /* TRUE: It is okay to write to this device */
size_t geo_nsectors; /* Number of sectors on the device */
size_t geo_sectorsize; /* Size of one sector */
};
/* This structure is provided by block devices when they register with the
* system. It is used by file systems to perform filesystem transfers. It
* differs from the normal driver vtable in several ways -- most notably in
* that it deals in struct inode vs. struct filep.
*/
struct inode;
struct block_operations
{
int (*open)(FAR struct inode *inode);
int (*close)(FAR struct inode *inode);
ssize_t (*read)(FAR struct inode *inode, FAR unsigned char *buffer,
size_t start_sector, unsigned int nsectors);
ssize_t (*write)(FAR struct inode *inode, FAR const unsigned char *buffer,
size_t start_sector, unsigned int nsectors);
int (*geometry)(FAR struct inode *inode, FAR struct geometry *geometry);
int (*ioctl)(FAR struct inode *inode, int cmd, unsigned long arg);
};
/* This structure is provided by a filesystem to describe a mount point.
* Note that this structure differs from file_operations ONLY in the form of
* the open method. Once the file is opened, it can be accessed either as a
* struct file_operations or struct mountpt_operations
*/
struct inode;
struct internal_dir_s;
struct stat;
struct statfs;
struct mountpt_operations
{
/* The mountpoint open method differs from the driver open method
* because it receives (1) the inode that contains the mountpoint
* private data, (2) the relative path into the mountpoint, and (3)
* information to manage privileges.
*/
int (*open)(FAR struct file *filp, 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 *filp);
ssize_t (*read)(FAR struct file *filp, FAR char *buffer, size_t buflen);
ssize_t (*write)(FAR struct file *filp, FAR const char *buffer, size_t buflen);
off_t (*seek)(FAR struct file *filp, off_t offset, int whence);
int (*ioctl)(FAR struct file *filp, int cmd, unsigned long arg);
/* 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 mountpoint operations:
*/
int (*sync)(FAR struct file *filp);
/* Directory operations */
int (*opendir)(FAR struct inode *mountpt, FAR const char *relpath, FAR struct internal_dir_s *dir);
int (*closedir)(FAR struct inode *mountpt, FAR struct internal_dir_s *dir);
int (*readdir)(FAR struct inode *mountpt, FAR struct internal_dir_s *dir);
int (*rewinddir)(FAR struct inode *mountpt, FAR struct internal_dir_s *dir);
/* General volume-related mountpoint operations: */
int (*bind)(FAR struct inode *blkdriver, FAR const void *data, FAR void **handle);
int (*unbind)(FAR void *handle, FAR struct inode **blkdriver);
int (*statfs)(FAR struct inode *mountpt, FAR struct statfs *buf);
/* Operations on pathes */
int (*unlink)(FAR struct inode *mountpt, FAR const char *relpath);
int (*mkdir)(FAR struct inode *mountpt, FAR const char *relpath, mode_t mode);
int (*rmdir)(FAR struct inode *mountpt, FAR const char *relpath);
int (*rename)(FAR struct inode *mountpt, FAR const char *oldrelpath, FAR const char *newrelpath);
int (*stat)(FAR struct inode *mountpt, FAR const char *relpath, FAR struct stat *buf);
/* NOTE: More operations will be needed here to support: disk usage stats
* file stat(), file attributes, file truncation, etc.
*/
};
#endif /* CONFIG_DISABLE_MOUNTPOUNT */
/* These are the various kinds of operations that can be associated with
* an inode.
*/
union inode_ops_u
{
FAR const struct file_operations *i_ops; /* Driver operations for inode */
#ifndef CONFIG_DISABLE_MOUNTPOUNT
FAR const struct block_operations *i_bops; /* Block driver operations */
FAR const struct mountpt_operations *i_mops; /* Operations on a mountpoint */
#endif
};
/* This structure represents one inode in the Nuttx psuedo-file system */
struct inode
{
FAR struct inode *i_peer; /* Pointer to same level inode */
FAR struct inode *i_child; /* Pointer to lower level inode */
sint16 i_crefs; /* References to inode */
uint16 i_flags; /* Flags for inode */
union inode_ops_u u; /* Inode operations */
#ifdef CONFIG_FILE_MODE
mode_t i_mode; /* Access mode flags */
#endif
FAR void *i_private; /* Per inode driver private data */
char i_name[1]; /* Name of inode (variable) */
};
#define FSNODE_SIZE(n) (sizeof(struct inode) + (n))
/* This is the underlying representation of an open file. A file
* descriptor is an index into an array of such types. The type associates
* the file descriptor to the file state and to a set of inode operations.
*/
struct file
{
int f_oflags; /* Open mode flags */
off_t f_pos; /* File position */
FAR struct inode *f_inode; /* Driver interface */
void *f_priv; /* Per file driver private data */
};
/* This defines a list of files indexed by the file descriptor */
#if CONFIG_NFILE_DESCRIPTORS > 0
struct filelist
{
sem_t fl_sem; /* Manage access to the file list */
sint16 fl_crefs; /* Reference count */
struct file fl_files[CONFIG_NFILE_DESCRIPTORS];
};
#endif
/* The following structure defines the list of files used for standard C I/O.
* Note that NuttX can support the standard C APIs without or without buffering
*
* When buffering us used, the following described the usage of the I/O buffer.
* The buffer can be used for reading or writing -- but not both at the same time.
* An fflush is implied between each change in directionof access.
*
* The field fs_bufread determines whether the buffer is being used for reading or
* for writing as fillows:
*
* BUFFER
* +----------------------+ <- fs_bufstart Points to the beginning of the buffer.
* | WR: Buffered data | WR: Start of buffered write data.
* | RD: Already read | RD: Start of already read data.
* +----------------------+
* | WR: Available buffer | <- fs_bufpos Points to next byte:
* | RD: Read-ahead data | WR: End+1 of buffered write data.
* | | RD: Points to next char to return
* +----------------------+
* | WR: Available | <- fs_bufread Top+1 of buffered read data
* | RD: Available | WR: =bufstart buffer used for writing.
* | | RD: Pointer to last buffered read char+1
* +----------------------+
* <- fs_bufend Points to end end of the buffer+1
*/
#if CONFIG_NFILE_STREAMS > 0
struct file_struct
{
int fs_filedes; /* File descriptor associated with stream */
mode_t fs_oflags; /* Open mode flags */
#if CONFIG_NUNGET_CHARS > 0
uint8 fs_nungotten; /* The number of characters buffered for ungetc */
unsigned char fs_ungotten[CONFIG_NUNGET_CHARS];
#endif
#if CONFIG_STDIO_BUFFER_SIZE > 0
sem_t fs_sem; /* For thread safety */
pid_t fs_holder; /* Holder of sem */
int fs_counts; /* Number of times sem is held */
FAR unsigned char *fs_bufstart; /* Pointer to start of buffer */
FAR unsigned char *fs_bufend; /* Pointer to 1 past end of buffer */
FAR unsigned char *fs_bufpos; /* Current position in buffer */
FAR unsigned char *fs_bufread; /* Pointer to 1 past last buffered read char. */
#endif
};
struct streamlist
{
int sl_crefs; /* Reference count */
sem_t sl_sem; /* For thread safety */
struct file_struct sl_streams[CONFIG_NFILE_STREAMS];
};
#endif /* CONFIG_NFILE_STREAMS */
/****************************************************************************
* Global Function Prototypes
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif
/* fs_inode.c ***************************************************************/
/* These interfaces are used by drivers to register their
* inodes in the inode tree.
*/
EXTERN void weak_function fs_initialize(void);
/* fs_registerdriver.c ******************************************************/
EXTERN STATUS register_driver(const char *path,
const struct file_operations *fops,
mode_t mode, void *private);
/* fs_registerdriver.c ******************************************************/
EXTERN STATUS register_blockdriver(const char *path,
const struct block_operations *bops,
mode_t mode, void *private);
/* fs_unregisterdriver.c ****************************************************/
EXTERN STATUS unregister_driver(const char *path);
/* fs_unregisterblockdriver.c ***********************************************/
EXTERN STATUS unregister_blockdriver(const char *path);
/* fs_open.c ****************************************************************/
EXTERN int inode_checkflags(FAR struct inode *inode, int oflags);
/* fs_files.c ***************************************************************/
#if CONFIG_NFILE_DESCRIPTORS >0
EXTERN FAR struct filelist *files_alloclist(void);
EXTERN int files_addreflist(FAR struct filelist *list);
EXTERN int files_releaselist(FAR struct filelist *list);
EXTERN int files_dup(FAR struct file *filep1, FAR struct file *filep2);
/* fs_openblockdriver.c ******************************************************/
EXTERN int open_blockdriver(FAR const char *pathname, int mountflags,
FAR struct inode **ppinode);
/* fs_closeblockdriver.c *****************************************************/
EXTERN int close_blockdriver(FAR struct inode *inode);
#endif
/* lib_fopen.c **************************************************************/
/* Used by the OS to clone stdin, stdout, stderr */
#if CONFIG_NFILE_STREAMS > 0
EXTERN FAR struct file_struct *lib_fdopen(int fd,
const char *mode,
FAR struct filelist *flist,
FAR struct streamlist *slist);
#endif
/* lib_fflush.c *************************************************************/
#if CONFIG_NFILE_STREAMS > 0
EXTERN int lib_flushall(FAR struct streamlist *list);
#endif
/* drivers ******************************************************************/
/* Call any of these to register the corresponding drivers in the drivers/
* subdirectory
*/
/* Register /dev/null and /dev/zero */
EXTERN void devnull_register(void);
EXTERN void devzero_register(void);
/* Setup the loop device so that it exports the file referenced by 'filename'
* as a block device.
*/
EXTERN int losetup(const char *devname, const char *filename, uint16 sectsize,
off_t offset, boolean readonly);
EXTERN int loteardown(const char *devname);
/* Setup so that the block driver referenced by 'blkdev' can be accessed
* similar to a character device.
*
* Access via a character device:
*/
EXTERN int bchdev_register(const char *blkdev, const char *chardev, boolean readonly);
EXTERN int bchdev_unregister(const char *chardev);
/* Low level, direct access. NOTE: low-level access and character driver access
* are incompatible. One and only one access method should be implemented.
*/
EXTERN int bchlib_setup(const char *blkdev, boolean readonly, FAR void **handle);
EXTERN int bchlib_teardown(FAR void *handle);
EXTERN ssize_t bchlib_read(FAR void *handle, FAR char *buffer, size_t offset, size_t len);
EXTERN ssize_t bchlib_write(FAR void *handle, FAR const char *buffer, size_t offset, size_t len);
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __NUTTX_FS_H */
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