fuse.h

UNIX/LINUX下面的用户文件系统

    /**
     * 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);
};

/** 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;
};

/*
 * 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);

/**
 * Check if a request has already been interrupted
 *
 * @param req request handle
 * @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);

/*
 * 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_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_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_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);
void fuse_fs_init(struct fuse_fs *fs, struct fuse_conn_info *conn);
void fuse_fs_destroy(struct fuse_fs *fs);

/**
 * 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);

/* ----------------------------------------------------------- *
 * Compatibility stuff                                         *
 * ----------------------------------------------------------- */

#if FUSE_USE_VERSION < 26
#  include "fuse_compat.h"
#  undef fuse_main
#  if FUSE_USE_VERSION == 25
#    define fuse_main(argc, argv, op) \
            fuse_main_real_compat25(argc, argv, op, sizeof(*(op)))
#    define fuse_new fuse_new_compat25
#    define fuse_setup fuse_setup_compat25
#    define fuse_teardown fuse_teardown_compat22
#    define fuse_operations fuse_operations_compat25
#  elif FUSE_USE_VERSION == 22
#    define fuse_main(argc, argv, op) \
            fuse_main_real_compat22(argc, argv, op, sizeof(*(op)))
#    define fuse_new fuse_new_compat22
#    define fuse_setup fuse_setup_compat22
#    define fuse_teardown fuse_teardown_compat22
#    define fuse_operations fuse_operations_compat22
#    define fuse_file_info fuse_file_info_compat
#  elif FUSE_USE_VERSION == 24
#    error Compatibility with high-level API version 24 not supported
#  else
#    define fuse_dirfil_t fuse_dirfil_t_compat
#    define __fuse_read_cmd fuse_read_cmd
#    define __fuse_process_cmd fuse_process_cmd
#    define __fuse_loop_mt fuse_loop_mt_proc
#    if FUSE_USE_VERSION == 21
#      define fuse_operations fuse_operations_compat2
#      define fuse_main fuse_main_compat2
#      define fuse_new fuse_new_compat2
#      define __fuse_setup fuse_setup_compat2
#      define __fuse_teardown fuse_teardown_compat22
#      define __fuse_exited fuse_exited
#      define __fuse_set_getcontext_func fuse_set_getcontext_func
#    else
#      define fuse_statfs fuse_statfs_compat1
#      define fuse_operations fuse_operations_compat1
#      define fuse_main fuse_main_compat1
#      define fuse_new fuse_new_compat1
#      define FUSE_DEBUG FUSE_DEBUG_COMPAT1
#    endif
#  endif
#endif

#ifdef __cplusplus
}
#endif

#endif /* _FUSE_H_ */