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- /*
- FUSE: Filesystem in Userspace
- Copyright (C) 2001-2006 Miklos Szeredi <miklos@szeredi.hu>
-
- This program can be distributed under the terms of the GNU LGPL.
- See the file COPYING.LIB.
- */
-
- #ifndef _FUSE_H_
- #define _FUSE_H_
-
- /* This file defines the library interface of FUSE */
-
- /* IMPORTANT: you should define FUSE_USE_VERSION before including this
- header. To use the newest API define it to 26 (recommended for any
- new application), to use the old API define it to 21 (default) 22
- or 25, to use the even older 1.X API define it to 11. */
-
- #ifndef FUSE_USE_VERSION
- #define FUSE_USE_VERSION 21
- #endif
-
- #include "fuse_common.h"
-
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <sys/statvfs.h>
- #include <utime.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, init and
- * destroy are special purpose methods, without which a full featured
- * filesystem can still be implemented.
- */
- struct fuse_operations {
- /** 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
- *
- * There is no create() operation, mknod() will be called for
- * creation of all non-directory, non-symlink nodes.
- */
- int (*mknod) (const char *, mode_t, dev_t);
-
- /** Create a directory */
- 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 */
- int (*utime) (const char *, struct utimbuf *);
-
- /** File open operation
- *
- * No creation, or truncation flags (O_CREAT, O_EXCL, O_TRUNC)
- * will be passed to open(). 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 *);
-
- /** Just a placeholder, don't set */
- /** 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
- *
- * This method should check if the open operation is permitted for
- * this directory
- *
- * 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
- */
- 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 *);
- };
-
- /** 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
- * @return 0 on success, nonzero on failure
- */
- /*
- int fuse_main(int argc, char *argv[], const struct fuse_operations *op);
- */
- #define fuse_main(argc, argv, op) \
- fuse_main_real(argc, argv, op, sizeof(*(op)))
-
- /* ----------------------------------------------------------- *
- * More detailed API *
- * ----------------------------------------------------------- */
-
- /**
- * Create a new FUSE filesystem.
- *
- * @param fd the control file descriptor
- * @param args argument vector
- * @param op the operations
- * @param op_size the size of the fuse_operations structure
- * @return the created FUSE handle
- */
- struct fuse *fuse_new(int fd, struct fuse_args *args,
- const struct fuse_operations *op, size_t op_size);
-
- /**
- * Destroy the FUSE handle.
- *
- * The filesystem is not unmounted.
- *
- * @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.
- *
- * @param f the FUSE handle
- * @return the context
- */
- struct fuse_context *fuse_get_context(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);
-
- /* ----------------------------------------------------------- *
- * Advanced API for event handling, don't worry about this... *
- * ----------------------------------------------------------- */
-
- /** 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, int *fd);
-
- /** This is the part of fuse_main() after the event loop */
- void fuse_teardown(struct fuse *fuse, int fd, 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);
-
- /** Set function which can be used to get the current context */
- void fuse_set_getcontext_func(struct fuse_context *(*func)(void));
-
- /* ----------------------------------------------------------- *
- * 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_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_operations fuse_operations_compat22
- # define fuse_file_info fuse_file_info_compat22
- # 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
- # 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_ */
-