libfuse-fix-fs-cleanup

[fuse.git] / include / fuse.h

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB.
*/

#ifndef _FUSE_H_
#define _FUSE_H_

/** @file
 *
 * This file defines the library interface of FUSE
 *
 * IMPORTANT: you should define FUSE_USE_VERSION before including this header.
 */

#include "fuse_common.h"

#include <fcntl.h>
#include <time.h>
#include <utime.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/uio.h>

#ifdef __cplusplus
extern "C" {
#endif

/* ----------------------------------------------------------- *
 * Basic FUSE API                                              *
 * ----------------------------------------------------------- */

/** Handle for a FUSE filesystem */
struct fuse;

/** Structure containing a raw command */
struct fuse_cmd;

/** Function to add an entry in a readdir() operation
 *
 * @param buf the buffer passed to the readdir() operation
 * @param name the file name of the directory entry
 * @param stat file attributes, can be NULL
 * @param off offset of the next entry or zero
 * @return 1 if buffer is full, zero otherwise
 */
typedef int (*fuse_fill_dir_t) (void *buf, const char *name,
                                const struct stat *stbuf, off_t off);

/* Used by deprecated getdir() method */
typedef struct fuse_dirhandle *fuse_dirh_t;
typedef int (*fuse_dirfil_t) (fuse_dirh_t h, const char *name, int type,
                              ino_t ino);

/**
 * The file system operations:
 *
 * Most of these should work very similarly to the well known UNIX
 * file system operations.  A major exception is that instead of
 * returning an error in 'errno', the operation should return the
 * negated error value (-errno) directly.
 *
 * All methods are optional, but some are essential for a useful
 * filesystem (e.g. getattr).  Open, flush, release, fsync, opendir,
 * releasedir, fsyncdir, access, create, ftruncate, fgetattr, lock,
 * init and destroy are special purpose methods, without which a full
 * featured filesystem can still be implemented.
 *
 * Almost all operations take a path which can be of any length.
 *
 * Changed in fuse 2.8.0 (regardless of API version)
 * Previously, paths were limited to a length of PATH_MAX.
 *
 * See http://fuse.sourceforge.net/wiki/ for more information.  There
 * is also a snapshot of the relevant wiki pages in the doc/ folder.
 */
struct fuse_operations {
        /**
         * Flag indicating that the path need not be calculated for
         * the following operations:
         *
         * read, write, flush, release, fsync, readdir, releasedir,
         * fsyncdir, ftruncate, fgetattr, lock, ioctl and poll
         *
         * If this flag is set then the path will not be calculaged even if the
         * file wasn't unlinked.  However the path can still be non-NULL if it
         * needs to be calculated for some other reason.
         */
        unsigned int flag_nopath:1;

        /**
         * Flag indicating that the filesystem accepts special
         * UTIME_NOW and UTIME_OMIT values in its utimens operation.
         */
        unsigned int flag_utime_omit_ok:1;

        /**
         * Reserved flags, don't set
         */
        unsigned int flag_reserved:30;

        /** Get file attributes.
         *
         * Similar to stat().  The 'st_dev' and 'st_blksize' fields are
         * ignored.      The 'st_ino' field is ignored except if the 'use_ino'
         * mount option is given.
         */
        int (*getattr) (const char *, struct stat *);

        /** Read the target of a symbolic link
         *
         * The buffer should be filled with a null terminated string.  The
         * buffer size argument includes the space for the terminating
         * null character.      If the linkname is too long to fit in the
         * buffer, it should be truncated.      The return value should be 0
         * for success.
         */
        int (*readlink) (const char *, char *, size_t);

        /* Deprecated, use readdir() instead */
        int (*getdir) (const char *, fuse_dirh_t, fuse_dirfil_t);

        /** Create a file node
         *
         * This is called for creation of all non-directory, non-symlink
         * nodes.  If the filesystem defines a create() method, then for
         * regular files that will be called instead.
         */
        int (*mknod) (const char *, mode_t, dev_t);

        /** Create a directory 
         *
         * Note that the mode argument may not have the type specification
         * bits set, i.e. S_ISDIR(mode) can be false.  To obtain the
         * correct directory type bits use  mode|S_IFDIR
         * */
        int (*mkdir) (const char *, mode_t);

        /** Remove a file */
        int (*unlink) (const char *);

        /** Remove a directory */
        int (*rmdir) (const char *);

        /** Create a symbolic link */
        int (*symlink) (const char *, const char *);

        /** Rename a file */
        int (*rename) (const char *, const char *);

        /** Create a hard link to a file */
        int (*link) (const char *, const char *);

        /** Change the permission bits of a file */
        int (*chmod) (const char *, mode_t);

        /** Change the owner and group of a file */
        int (*chown) (const char *, uid_t, gid_t);

        /** Change the size of a file */
        int (*truncate) (const char *, off_t);

        /** Change the access and/or modification times of a file
         *
         * Deprecated, use utimens() instead.
         */
        int (*utime) (const char *, struct utimbuf *);

        /** File open operation
         *
         * No creation (O_CREAT, O_EXCL) and by default also no
         * truncation (O_TRUNC) flags will be passed to open(). If an
         * application specifies O_TRUNC, fuse first calls truncate()
         * and then open(). Only if 'atomic_o_trunc' has been
         * specified and kernel version is 2.6.24 or later, O_TRUNC is
         * passed on to open.
         *
         * Unless the 'default_permissions' mount option is given,
         * open should check if the operation is permitted for the
         * given flags. Optionally open may also return an arbitrary
         * filehandle in the fuse_file_info structure, which will be
         * passed to all file operations.
         *
         * Changed in version 2.2
         */
        int (*open) (const char *, struct fuse_file_info *);

        /** Read data from an open file
         *
         * Read should return exactly the number of bytes requested except
         * on EOF or error, otherwise the rest of the data will be
         * substituted with zeroes.      An exception to this is when the
         * 'direct_io' mount option is specified, in which case the return
         * value of the read system call will reflect the return value of
         * this operation.
         *
         * Changed in version 2.2
         */
        int (*read) (const char *, char *, size_t, off_t,
                     struct fuse_file_info *);

        /** Write data to an open file
         *
         * Write should return exactly the number of bytes requested
         * except on error.      An exception to this is when the 'direct_io'
         * mount option is specified (see read operation).
         *
         * Changed in version 2.2
         */
        int (*write) (const char *, const char *, size_t, off_t,
                      struct fuse_file_info *);

        /** Get file system statistics
         *
         * The 'f_frsize', 'f_favail', 'f_fsid' and 'f_flag' fields are ignored
         *
         * Replaced 'struct statfs' parameter with 'struct statvfs' in
         * version 2.5
         */
        int (*statfs) (const char *, struct statvfs *);

        /** Possibly flush cached data
         *
         * BIG NOTE: This is not equivalent to fsync().  It's not a
         * request to sync dirty data.
         *
         * Flush is called on each close() of a file descriptor.  So if a
         * filesystem wants to return write errors in close() and the file
         * has cached dirty data, this is a good place to write back data
         * and return any errors.  Since many applications ignore close()
         * errors this is not always useful.
         *
         * NOTE: The flush() method may be called more than once for each
         * open().      This happens if more than one file descriptor refers
         * to an opened file due to dup(), dup2() or fork() calls.      It is
         * not possible to determine if a flush is final, so each flush
         * should be treated equally.  Multiple write-flush sequences are
         * relatively rare, so this shouldn't be a problem.
         *
         * Filesystems shouldn't assume that flush will always be called
         * after some writes, or that if will be called at all.
         *
         * Changed in version 2.2
         */
        int (*flush) (const char *, struct fuse_file_info *);

        /** Release an open file
         *
         * Release is called when there are no more references to an open
         * file: all file descriptors are closed and all memory mappings
         * are unmapped.
         *
         * For every open() call there will be exactly one release() call
         * with the same flags and file descriptor.      It is possible to
         * have a file opened more than once, in which case only the last
         * release will mean, that no more reads/writes will happen on the
         * file.  The return value of release is ignored.
         *
         * Changed in version 2.2
         */
        int (*release) (const char *, struct fuse_file_info *);

        /** Synchronize file contents
         *
         * If the datasync parameter is non-zero, then only the user data
         * should be flushed, not the meta data.
         *
         * Changed in version 2.2
         */
        int (*fsync) (const char *, int, struct fuse_file_info *);

        /** Set extended attributes */
        int (*setxattr) (const char *, const char *, const char *, size_t, int);

        /** Get extended attributes */
        int (*getxattr) (const char *, const char *, char *, size_t);

        /** List extended attributes */
        int (*listxattr) (const char *, char *, size_t);

        /** Remove extended attributes */
        int (*removexattr) (const char *, const char *);

        /** Open directory
         *
         * Unless the 'default_permissions' mount option is given,
         * this method should check if opendir is permitted for this
         * directory. Optionally opendir may also return an arbitrary
         * filehandle in the fuse_file_info structure, which will be
         * passed to readdir, closedir and fsyncdir.
         *
         * Introduced in version 2.3
         */
        int (*opendir) (const char *, struct fuse_file_info *);

        /** Read directory
         *
         * This supersedes the old getdir() interface.  New applications
         * should use this.
         *
         * The filesystem may choose between two modes of operation:
         *
         * 1) The readdir implementation ignores the offset parameter, and
         * passes zero to the filler function's offset.  The filler
         * function will not return '1' (unless an error happens), so the
         * whole directory is read in a single readdir operation.  This
         * works just like the old getdir() method.
         *
         * 2) The readdir implementation keeps track of the offsets of the
         * directory entries.  It uses the offset parameter and always
         * passes non-zero offset to the filler function.  When the buffer
         * is full (or an error happens) the filler function will return
         * '1'.
         *
         * Introduced in version 2.3
         */
        int (*readdir) (const char *, void *, fuse_fill_dir_t, off_t,
                        struct fuse_file_info *);

        /** Release directory
         *
         * Introduced in version 2.3
         */
        int (*releasedir) (const char *, struct fuse_file_info *);

        /** Synchronize directory contents
         *
         * If the datasync parameter is non-zero, then only the user data
         * should be flushed, not the meta data
         *
         * Introduced in version 2.3
         */
        int (*fsyncdir) (const char *, int, struct fuse_file_info *);

        /**
         * Initialize filesystem
         *
         * The return value will passed in the private_data field of
         * fuse_context to all file operations and as a parameter to the
         * destroy() method.
         *
         * Introduced in version 2.3
         * Changed in version 2.6
         */
        void *(*init) (struct fuse_conn_info *conn);

        /**
         * Clean up filesystem
         *
         * Called on filesystem exit.
         *
         * Introduced in version 2.3
         */
        void (*destroy) (void *);

        /**
         * Check file access permissions
         *
         * This will be called for the access() system call.  If the
         * 'default_permissions' mount option is given, this method is not
         * called.
         *
         * This method is not called under Linux kernel versions 2.4.x
         *
         * Introduced in version 2.5
         */
        int (*access) (const char *, int);

        /**
         * Create and open a file
         *
         * If the file does not exist, first create it with the specified
         * mode, and then open it.
         *
         * If this method is not implemented or under Linux kernel
         * versions earlier than 2.6.15, the mknod() and open() methods
         * will be called instead.
         *
         * Introduced in version 2.5
         */
        int (*create) (const char *, mode_t, struct fuse_file_info *);

        /**
         * Change the size of an open file
         *
         * This method is called instead of the truncate() method if the
         * truncation was invoked from an ftruncate() system call.
         *
         * If this method is not implemented or under Linux kernel
         * versions earlier than 2.6.15, the truncate() method will be
         * called instead.
         *
         * Introduced in version 2.5
         */
        int (*ftruncate) (const char *, off_t, struct fuse_file_info *);

        /**
         * Get attributes from an open file
         *
         * This method is called instead of the getattr() method if the
         * file information is available.
         *
         * Currently this is only called after the create() method if that
         * is implemented (see above).  Later it may be called for
         * invocations of fstat() too.
         *
         * Introduced in version 2.5
         */
        int (*fgetattr) (const char *, struct stat *, struct fuse_file_info *);

        /**
         * Perform POSIX file locking operation
         *
         * The cmd argument will be either F_GETLK, F_SETLK or F_SETLKW.
         *
         * For the meaning of fields in 'struct flock' see the man page
         * for fcntl(2).  The l_whence field will always be set to
         * SEEK_SET.
         *
         * For checking lock ownership, the 'fuse_file_info->owner'
         * argument must be used.
         *
         * For F_GETLK operation, the library will first check currently
         * held locks, and if a conflicting lock is found it will return
         * information without calling this method.      This ensures, that
         * for local locks the l_pid field is correctly filled in.      The
         * results may not be accurate in case of race conditions and in
         * the presence of hard links, but it's unlikely that an
         * application would rely on accurate GETLK results in these
         * cases.  If a conflicting lock is not found, this method will be
         * called, and the filesystem may fill out l_pid by a meaningful
         * value, or it may leave this field zero.
         *
         * For F_SETLK and F_SETLKW the l_pid field will be set to the pid
         * of the process performing the locking operation.
         *
         * Note: if this method is not implemented, the kernel will still
         * allow file locking to work locally.  Hence it is only
         * interesting for network filesystems and similar.
         *
         * Introduced in version 2.6
         */
        int (*lock) (const char *, struct fuse_file_info *, int cmd,
                     struct flock *);

        /**
         * Change the access and modification times of a file with
         * nanosecond resolution
         *
         * This supersedes the old utime() interface.  New applications
         * should use this.
         *
         * See the utimensat(2) man page for details.
         *
         * Introduced in version 2.6
         */
        int (*utimens) (const char *, const struct timespec tv[2]);

        /**
         * Map block index within file to block index within device
         *
         * Note: This makes sense only for block device backed filesystems
         * mounted with the 'blkdev' option
         *
         * Introduced in version 2.6
         */
        int (*bmap) (const char *, size_t blocksize, uint64_t *idx);

        /**
         * Ioctl
         *
         * flags will have FUSE_IOCTL_COMPAT set for 32bit ioctls in
         * 64bit environment.  The size and direction of data is
         * determined by _IOC_*() decoding of cmd.  For _IOC_NONE,
         * data will be NULL, for _IOC_WRITE data is out area, for
         * _IOC_READ in area and if both are set in/out area.  In all
         * non-NULL cases, the area is of _IOC_SIZE(cmd) bytes.
         *
         * Introduced in version 2.8
         */
        int (*ioctl) (const char *, int cmd, void *arg,
                      struct fuse_file_info *, unsigned int flags, void *data);

        /**
         * Poll for IO readiness events
         *
         * Note: If ph is non-NULL, the client should notify
         * when IO readiness events occur by calling
         * fuse_notify_poll() with the specified ph.
         *
         * Regardless of the number of times poll with a non-NULL ph
         * is received, single notification is enough to clear all.
         * Notifying more times incurs overhead but doesn't harm
         * correctness.
         *
         * The callee is responsible for destroying ph with
         * fuse_pollhandle_destroy() when no longer in use.
         *
         * Introduced in version 2.8
         */
        int (*poll) (const char *, struct fuse_file_info *,
                     struct fuse_pollhandle *ph, unsigned *reventsp);

        /** Write contents of buffer to an open file
         *
         * Similar to the write() method, but data is supplied in a
         * generic buffer.  Use fuse_buf_copy() to transfer data to
         * the destination.
         *
         * Introduced in version 2.9
         */
        int (*write_buf) (const char *, struct fuse_bufvec *buf, off_t off,
                          struct fuse_file_info *);

        /** Store data from an open file in a buffer
         *
         * Similar to the read() method, but data is stored and
         * returned in a generic buffer.
         *
         * No actual copying of data has to take place, the source
         * file descriptor may simply be stored in the buffer for
         * later data transfer.
         *
         * The buffer must be allocated dynamically and stored at the
         * location pointed to by bufp.  If the buffer contains memory
         * regions, they too must be allocated using malloc().  The
         * allocated memory will be freed by the caller.
         *
         * Introduced in version 2.9
         */
        int (*read_buf) (const char *, struct fuse_bufvec **bufp,
                         size_t size, off_t off, struct fuse_file_info *);
        /**
         * Perform BSD file locking operation
         *
         * The op argument will be either LOCK_SH, LOCK_EX or LOCK_UN
         *
         * Nonblocking requests will be indicated by ORing LOCK_NB to
         * the above operations
         *
         * For more information see the flock(2) manual page.
         *
         * Additionally fi->owner will be set to a value unique to
         * this open file.  This same value will be supplied to
         * ->release() when the file is released.
         *
         * Note: if this method is not implemented, the kernel will still
         * allow file locking to work locally.  Hence it is only
         * interesting for network filesystems and similar.
         *
         * Introduced in version 2.9
         */
        int (*flock) (const char *, struct fuse_file_info *, int op);

        /**
         * Allocates space for an open file
         *
         * This function ensures that required space is allocated for specified
         * file.  If this function returns success then any subsequent write
         * request to specified range is guaranteed not to fail because of lack
         * of space on the file system media.
         *
         * Introduced in version 2.9.1
         */
        int (*fallocate) (const char *, int, off_t, off_t,
                          struct fuse_file_info *);
};

/** Extra context that may be needed by some filesystems
 *
 * The uid, gid and pid fields are not filled in case of a writepage
 * operation.
 */
struct fuse_context {
        /** Pointer to the fuse object */
        struct fuse *fuse;

        /** User ID of the calling process */
        uid_t uid;

        /** Group ID of the calling process */
        gid_t gid;

        /** Thread ID of the calling process */
        pid_t pid;

        /** Private filesystem data */
        void *private_data;

        /** Umask of the calling process (introduced in version 2.8) */
        mode_t umask;
};

/**
 * Main function of FUSE.
 *
 * This is for the lazy.  This is all that has to be called from the
 * main() function.
 *
 * This function does the following:
 *   - parses command line options (-d -s and -h)
 *   - passes relevant mount options to the fuse_mount()
 *   - installs signal handlers for INT, HUP, TERM and PIPE
 *   - registers an exit handler to unmount the filesystem on program exit
 *   - creates a fuse handle
 *   - registers the operations
 *   - calls either the single-threaded or the multi-threaded event loop
 *
 * Note: this is currently implemented as a macro.
 *
 * @param argc the argument counter passed to the main() function
 * @param argv the argument vector passed to the main() function
 * @param op the file system operation
 * @param user_data user data supplied in the context during the init() method
 * @return 0 on success, nonzero on failure
 */
/*
  int fuse_main(int argc, char *argv[], const struct fuse_operations *op,
  void *user_data);
*/
#define fuse_main(argc, argv, op, user_data)                            \
        fuse_main_real(argc, argv, op, sizeof(*(op)), user_data)

/* ----------------------------------------------------------- *
 * More detailed API                                           *
 * ----------------------------------------------------------- */

/**
 * Create a new FUSE filesystem.
 *
 * @param ch the communication channel
 * @param args argument vector
 * @param op the filesystem operations
 * @param op_size the size of the fuse_operations structure
 * @param user_data user data supplied in the context during the init() method
 * @return the created FUSE handle
 */
struct fuse *fuse_new(struct fuse_chan *ch, struct fuse_args *args,
                      const struct fuse_operations *op, size_t op_size,
                      void *user_data);

/**
 * Destroy the FUSE handle.
 *
 * The communication channel attached to the handle is also destroyed.
 *
 * NOTE: This function does not unmount the filesystem.  If this is
 * needed, call fuse_unmount() before calling this function.
 *
 * @param f the FUSE handle
 */
void fuse_destroy(struct fuse *f);

/**
 * FUSE event loop.
 *
 * Requests from the kernel are processed, and the appropriate
 * operations are called.
 *
 * @param f the FUSE handle
 * @return 0 if no error occurred, -1 otherwise
 */
int fuse_loop(struct fuse *f);

/**
 * Exit from event loop
 *
 * @param f the FUSE handle
 */
void fuse_exit(struct fuse *f);

/**
 * FUSE event loop with multiple threads
 *
 * Requests from the kernel are processed, and the appropriate
 * operations are called.  Request are processed in parallel by
 * distributing them between multiple threads.
 *
 * Calling this function requires the pthreads library to be linked to
 * the application.
 *
 * @param f the FUSE handle
 * @return 0 if no error occurred, -1 otherwise
 */
int fuse_loop_mt(struct fuse *f);

/**
 * Get the current context
 *
 * The context is only valid for the duration of a filesystem
 * operation, and thus must not be stored and used later.
 *
 * @return the context
 */
struct fuse_context *fuse_get_context(void);

/**
 * Get the current supplementary group IDs for the current request
 *
 * Similar to the getgroups(2) system call, except the return value is
 * always the total number of group IDs, even if it is larger than the
 * specified size.
 *
 * The current fuse kernel module in linux (as of 2.6.30) doesn't pass
 * the group list to userspace, hence this function needs to parse
 * "/proc/$TID/task/$TID/status" to get the group IDs.
 *
 * This feature may not be supported on all operating systems.  In
 * such a case this function will return -ENOSYS.
 *
 * @param size size of given array
 * @param list array of group IDs to be filled in
 * @return the total number of supplementary group IDs or -errno on failure
 */
int fuse_getgroups(int size, gid_t list[]);

/**
 * Check if the current request has already been interrupted
 *
 * @return 1 if the request has been interrupted, 0 otherwise
 */
int fuse_interrupted(void);

/**
 * Obsolete, doesn't do anything
 *
 * @return -EINVAL
 */
int fuse_invalidate(struct fuse *f, const char *path);

/* Deprecated, don't use */
int fuse_is_lib_option(const char *opt);

/**
 * The real main function
 *
 * Do not call this directly, use fuse_main()
 */
int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
                   size_t op_size, void *user_data);

/**
 * Start the cleanup thread when using option "remember".
 *
 * This is done automatically by fuse_loop_mt()
 * @param fuse struct fuse pointer for fuse instance
 * @return 0 on success and -1 on error
 */
int fuse_start_cleanup_thread(struct fuse *fuse);

/**
 * Stop the cleanup thread when using option "remember".
 *
 * This is done automatically by fuse_loop_mt()
 * @param fuse struct fuse pointer for fuse instance
 */
void fuse_stop_cleanup_thread(struct fuse *fuse);

/**
 * Iterate over cache removing stale entries
 * use in conjunction with "-oremember"
 *
 * NOTE: This is already done for the standard sessions
 *
 * @param fuse struct fuse pointer for fuse instance
 * @return the number of seconds until the next cleanup
 */
int fuse_clean_cache(struct fuse *fuse);

/*
 * Stacking API
 */

/**
 * Fuse filesystem object
 *
 * This is opaque object represents a filesystem layer
 */
struct fuse_fs;

/*
 * These functions call the relevant filesystem operation, and return
 * the result.
 *
 * If the operation is not defined, they return -ENOSYS, with the
 * exception of fuse_fs_open, fuse_fs_release, fuse_fs_opendir,
 * fuse_fs_releasedir and fuse_fs_statfs, which return 0.
 */

int fuse_fs_getattr(struct fuse_fs *fs, const char *path, struct stat *buf);
int fuse_fs_fgetattr(struct fuse_fs *fs, const char *path, struct stat *buf,
                     struct fuse_file_info *fi);
int fuse_fs_rename(struct fuse_fs *fs, const char *oldpath,
                   const char *newpath);
int fuse_fs_unlink(struct fuse_fs *fs, const char *path);
int fuse_fs_rmdir(struct fuse_fs *fs, const char *path);
int fuse_fs_symlink(struct fuse_fs *fs, const char *linkname,
                    const char *path);
int fuse_fs_link(struct fuse_fs *fs, const char *oldpath, const char *newpath);
int fuse_fs_release(struct fuse_fs *fs,  const char *path,
                    struct fuse_file_info *fi);
int fuse_fs_open(struct fuse_fs *fs, const char *path,
                 struct fuse_file_info *fi);
int fuse_fs_read(struct fuse_fs *fs, const char *path, char *buf, size_t size,
                 off_t off, struct fuse_file_info *fi);
int fuse_fs_read_buf(struct fuse_fs *fs, const char *path,
                     struct fuse_bufvec **bufp, size_t size, off_t off,
                     struct fuse_file_info *fi);
int fuse_fs_write(struct fuse_fs *fs, const char *path, const char *buf,
                  size_t size, off_t off, struct fuse_file_info *fi);
int fuse_fs_write_buf(struct fuse_fs *fs, const char *path,
                      struct fuse_bufvec *buf, off_t off,
                      struct fuse_file_info *fi);
int fuse_fs_fsync(struct fuse_fs *fs, const char *path, int datasync,
                  struct fuse_file_info *fi);
int fuse_fs_flush(struct fuse_fs *fs, const char *path,
                  struct fuse_file_info *fi);
int fuse_fs_statfs(struct fuse_fs *fs, const char *path, struct statvfs *buf);
int fuse_fs_opendir(struct fuse_fs *fs, const char *path,
                    struct fuse_file_info *fi);
int fuse_fs_readdir(struct fuse_fs *fs, const char *path, void *buf,
                    fuse_fill_dir_t filler, off_t off,
                    struct fuse_file_info *fi);
int fuse_fs_fsyncdir(struct fuse_fs *fs, const char *path, int datasync,
                     struct fuse_file_info *fi);
int fuse_fs_releasedir(struct fuse_fs *fs, const char *path,
                       struct fuse_file_info *fi);
int fuse_fs_create(struct fuse_fs *fs, const char *path, mode_t mode,
                   struct fuse_file_info *fi);
int fuse_fs_lock(struct fuse_fs *fs, const char *path,
                 struct fuse_file_info *fi, int cmd, struct flock *lock);
int fuse_fs_flock(struct fuse_fs *fs, const char *path,
                  struct fuse_file_info *fi, int op);
int fuse_fs_chmod(struct fuse_fs *fs, const char *path, mode_t mode);
int fuse_fs_chown(struct fuse_fs *fs, const char *path, uid_t uid, gid_t gid);
int fuse_fs_truncate(struct fuse_fs *fs, const char *path, off_t size);
int fuse_fs_ftruncate(struct fuse_fs *fs, const char *path, off_t size,
                      struct fuse_file_info *fi);
int fuse_fs_utimens(struct fuse_fs *fs, const char *path,
                    const struct timespec tv[2]);
int fuse_fs_access(struct fuse_fs *fs, const char *path, int mask);
int fuse_fs_readlink(struct fuse_fs *fs, const char *path, char *buf,
                     size_t len);
int fuse_fs_mknod(struct fuse_fs *fs, const char *path, mode_t mode,
                  dev_t rdev);
int fuse_fs_mkdir(struct fuse_fs *fs, const char *path, mode_t mode);
int fuse_fs_setxattr(struct fuse_fs *fs, const char *path, const char *name,
                     const char *value, size_t size, int flags);
int fuse_fs_getxattr(struct fuse_fs *fs, const char *path, const char *name,
                     char *value, size_t size);
int fuse_fs_listxattr(struct fuse_fs *fs, const char *path, char *list,
                      size_t size);
int fuse_fs_removexattr(struct fuse_fs *fs, const char *path,
                        const char *name);
int fuse_fs_bmap(struct fuse_fs *fs, const char *path, size_t blocksize,
                 uint64_t *idx);
int fuse_fs_ioctl(struct fuse_fs *fs, const char *path, int cmd, void *arg,
                  struct fuse_file_info *fi, unsigned int flags, void *data);
int fuse_fs_poll(struct fuse_fs *fs, const char *path,
                 struct fuse_file_info *fi, struct fuse_pollhandle *ph,
                 unsigned *reventsp);
int fuse_fs_fallocate(struct fuse_fs *fs, const char *path, int mode,
                 off_t offset, off_t length, struct fuse_file_info *fi);
void fuse_fs_init(struct fuse_fs *fs, struct fuse_conn_info *conn);
void fuse_fs_destroy(struct fuse_fs *fs);

int fuse_notify_poll(struct fuse_pollhandle *ph);

/**
 * Create a new fuse filesystem object
 *
 * This is usually called from the factory of a fuse module to create
 * a new instance of a filesystem.
 *
 * @param op the filesystem operations
 * @param op_size the size of the fuse_operations structure
 * @param user_data user data supplied in the context during the init() method
 * @return a new filesystem object
 */
struct fuse_fs *fuse_fs_new(const struct fuse_operations *op, size_t op_size,
                            void *user_data);

/**
 * Filesystem module
 *
 * Filesystem modules are registered with the FUSE_REGISTER_MODULE()
 * macro.
 *
 * If the "-omodules=modname:..." option is present, filesystem
 * objects are created and pushed onto the stack with the 'factory'
 * function.
 */
struct fuse_module {
        /**
         * Name of filesystem
         */
        const char *name;

        /**
         * Factory for creating filesystem objects
         *
         * The function may use and remove options from 'args' that belong
         * to this module.
         *
         * For now the 'fs' vector always contains exactly one filesystem.
         * This is the filesystem which will be below the newly created
         * filesystem in the stack.
         *
         * @param args the command line arguments
         * @param fs NULL terminated filesystem object vector
         * @return the new filesystem object
         */
        struct fuse_fs *(*factory)(struct fuse_args *args,
                                   struct fuse_fs *fs[]);

        struct fuse_module *next;
        struct fusemod_so *so;
        int ctr;
};

/**
 * Register a filesystem module
 *
 * This function is used by FUSE_REGISTER_MODULE and there's usually
 * no need to call it directly
 */
void fuse_register_module(struct fuse_module *mod);

/**
 * Register filesystem module
 *
 * For the parameters, see description of the fields in 'struct
 * fuse_module'
 */
#define FUSE_REGISTER_MODULE(name_, factory_)                             \
        static __attribute__((constructor)) void name_ ## _register(void) \
        {                                                                 \
                static struct fuse_module mod =                           \
                        { #name_, factory_, NULL, NULL, 0 };              \
                fuse_register_module(&mod);                               \
        }


/* ----------------------------------------------------------- *
 * Advanced API for event handling, don't worry about this...  *
 * ----------------------------------------------------------- */

/* NOTE: the following functions are deprecated, and will be removed
   from the 3.0 API.  Use the lowlevel session functions instead */

/** Function type used to process commands */
typedef void (*fuse_processor_t)(struct fuse *, struct fuse_cmd *, void *);

/** This is the part of fuse_main() before the event loop */
struct fuse *fuse_setup(int argc, char *argv[],
                        const struct fuse_operations *op, size_t op_size,
                        char **mountpoint, int *multithreaded,
                        void *user_data);

/** This is the part of fuse_main() after the event loop */
void fuse_teardown(struct fuse *fuse, char *mountpoint);

/** Read a single command.  If none are read, return NULL */
struct fuse_cmd *fuse_read_cmd(struct fuse *f);

/** Process a single command */
void fuse_process_cmd(struct fuse *f, struct fuse_cmd *cmd);

/** Multi threaded event loop, which calls the custom command
    processor function */
int fuse_loop_mt_proc(struct fuse *f, fuse_processor_t proc, void *data);

/** Return the exited flag, which indicates if fuse_exit() has been
    called */
int fuse_exited(struct fuse *f);

/** This function is obsolete and implemented as a no-op */
void fuse_set_getcontext_func(struct fuse_context *(*func)(void));

/** Get session from fuse object */
struct fuse_session *fuse_get_session(struct fuse *f);

#ifdef __cplusplus
}
#endif

#endif /* _FUSE_H_ */