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diff --git a/include/fuse-lite/fuse_lowlevel.h b/include/fuse-lite/fuse_lowlevel.h new file mode 100755 index 0000000..5b6dc6d --- a/dev/null +++ b/include/fuse-lite/fuse_lowlevel.h @@ -0,0 +1,1375 @@ +/* + 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_LOWLEVEL_H_ +#define _FUSE_LOWLEVEL_H_ + +/** @file + * + * Low level API + */ + +#include "fuse_common.h" + +#include <utime.h> +#include <fcntl.h> +#ifdef HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif + +#include <sys/stat.h> + +#if HAVE_SYS_STATVFS_H + +#include <sys/statvfs.h> +#endif + +#include <sys/uio.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* ----------------------------------------------------------- * + * Miscellaneous definitions * + * ----------------------------------------------------------- */ + +/** The node ID of the root inode */ +#define FUSE_ROOT_ID 1 + +/** Inode number type */ +typedef unsigned long fuse_ino_t; + +/** Request pointer type */ +typedef struct fuse_req *fuse_req_t; + +/** + * Session + * + * This provides hooks for processing requests, and exiting + */ +struct fuse_session; + +/** + * Channel + * + * A communication channel, providing hooks for sending and receiving + * messages + */ +struct fuse_chan; + +/** Directory entry parameters supplied to fuse_reply_entry() */ +struct fuse_entry_param { + /** Unique inode number + * + * In lookup, zero means negative entry (from version 2.5) + * Returning ENOENT also means negative entry, but by setting zero + * ino the kernel may cache negative entries for entry_timeout + * seconds. + */ + fuse_ino_t ino; + + /** Generation number for this entry. + * + * The ino/generation pair should be unique for the filesystem's + * lifetime. It must be non-zero, otherwise FUSE will treat it as an + * error. + */ + unsigned long generation; + + /** Inode attributes. + * + * Even if attr_timeout == 0, attr must be correct. For example, + * for open(), FUSE uses attr.st_size from lookup() to determine + * how many bytes to request. If this value is not correct, + * incorrect data will be returned. + */ + struct stat attr; + + /** Validity timeout (in seconds) for the attributes */ + double attr_timeout; + + /** Validity timeout (in seconds) for the name */ + double entry_timeout; +}; + +/** Additional context associated with requests */ +struct fuse_ctx { + /** 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; + +#ifdef POSIXACLS + /** Umask of the calling process (introduced in version 2.8) */ + mode_t umask; +#endif +}; + +/* 'to_set' flags in setattr */ +#define FUSE_SET_ATTR_MODE (1 << 0) +#define FUSE_SET_ATTR_UID (1 << 1) +#define FUSE_SET_ATTR_GID (1 << 2) +#define FUSE_SET_ATTR_SIZE (1 << 3) +#define FUSE_SET_ATTR_ATIME (1 << 4) +#define FUSE_SET_ATTR_MTIME (1 << 5) +#define FUSE_SET_ATTR_ATIME_NOW (1 << 7) +#define FUSE_SET_ATTR_MTIME_NOW (1 << 8) + +/* ----------------------------------------------------------- * + * Request methods and replies * + * ----------------------------------------------------------- */ + +/** + * Low level filesystem operations + * + * Most of the methods (with the exception of init and destroy) + * receive a request handle (fuse_req_t) as their first argument. + * This handle must be passed to one of the specified reply functions. + * + * This may be done inside the method invocation, or after the call + * has returned. The request handle is valid until one of the reply + * functions is called. + * + * Other pointer arguments (name, fuse_file_info, etc) are not valid + * after the call has returned, so if they are needed later, their + * contents have to be copied. + * + * The filesystem sometimes needs to handle a return value of -ENOENT + * from the reply function, which means, that the request was + * interrupted, and the reply discarded. For example if + * fuse_reply_open() return -ENOENT means, that the release method for + * this file will not be called. + */ +struct fuse_lowlevel_ops { + /** + * Initialize filesystem + * + * Called before any other filesystem method + * + * There's no reply to this function + * + * @param userdata the user data passed to fuse_lowlevel_new() + */ + void (*init) (void *userdata, struct fuse_conn_info *conn); + + /** + * Clean up filesystem + * + * Called on filesystem exit + * + * There's no reply to this function + * + * @param userdata the user data passed to fuse_lowlevel_new() + */ + void (*destroy) (void *userdata); + + /** + * Look up a directory entry by name and get its attributes. + * + * Valid replies: + * fuse_reply_entry + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the parent directory + * @param name the name to look up + */ + void (*lookup) (fuse_req_t req, fuse_ino_t parent, const char *name); + + /** + * Forget about an inode + * + * The nlookup parameter indicates the number of lookups + * previously performed on this inode. + * + * If the filesystem implements inode lifetimes, it is recommended + * that inodes acquire a single reference on each lookup, and lose + * nlookup references on each forget. + * + * The filesystem may ignore forget calls, if the inodes don't + * need to have a limited lifetime. + * + * On unmount it is not guaranteed, that all referenced inodes + * will receive a forget message. + * + * Valid replies: + * fuse_reply_none + * + * @param req request handle + * @param ino the inode number + * @param nlookup the number of lookups to forget + */ + void (*forget) (fuse_req_t req, fuse_ino_t ino, unsigned long nlookup); + + /** + * Get file attributes + * + * Valid replies: + * fuse_reply_attr + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi for future use, currently always NULL + */ + void (*getattr) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi); + + /** + * Set file attributes + * + * In the 'attr' argument only members indicated by the 'to_set' + * bitmask contain valid values. Other members contain undefined + * values. + * + * If the setattr was invoked from the ftruncate() system call + * under Linux kernel versions 2.6.15 or later, the fi->fh will + * contain the value set by the open method or will be undefined + * if the open method didn't set any value. Otherwise (not + * ftruncate call, or kernel version earlier than 2.6.15) the fi + * parameter will be NULL. + * + * Valid replies: + * fuse_reply_attr + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param attr the attributes + * @param to_set bit mask of attributes which should be set + * @param fi file information, or NULL + * + * Changed in version 2.5: + * file information filled in for ftruncate + */ + void (*setattr) (fuse_req_t req, fuse_ino_t ino, struct stat *attr, + int to_set, struct fuse_file_info *fi); + + /** + * Read symbolic link + * + * Valid replies: + * fuse_reply_readlink + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + */ + void (*readlink) (fuse_req_t req, fuse_ino_t ino); + + /** + * Create file node + * + * Create a regular file, character device, block device, fifo or + * socket node. + * + * Valid replies: + * fuse_reply_entry + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the parent directory + * @param name to create + * @param mode file type and mode with which to create the new file + * @param rdev the device number (only valid if created file is a device) + */ + void (*mknod) (fuse_req_t req, fuse_ino_t parent, const char *name, + mode_t mode, dev_t rdev); + + /** + * Create a directory + * + * Valid replies: + * fuse_reply_entry + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the parent directory + * @param name to create + * @param mode with which to create the new file + */ + void (*mkdir) (fuse_req_t req, fuse_ino_t parent, const char *name, + mode_t mode); + + /** + * Remove a file + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the parent directory + * @param name to remove + */ + void (*unlink) (fuse_req_t req, fuse_ino_t parent, const char *name); + + /** + * Remove a directory + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the parent directory + * @param name to remove + */ + void (*rmdir) (fuse_req_t req, fuse_ino_t parent, const char *name); + + /** + * Create a symbolic link + * + * Valid replies: + * fuse_reply_entry + * fuse_reply_err + * + * @param req request handle + * @param link the contents of the symbolic link + * @param parent inode number of the parent directory + * @param name to create + */ + void (*symlink) (fuse_req_t req, const char *link, fuse_ino_t parent, + const char *name); + + /** Rename a file + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the old parent directory + * @param name old name + * @param newparent inode number of the new parent directory + * @param newname new name + */ + void (*rename) (fuse_req_t req, fuse_ino_t parent, const char *name, + fuse_ino_t newparent, const char *newname); + + /** + * Create a hard link + * + * Valid replies: + * fuse_reply_entry + * fuse_reply_err + * + * @param req request handle + * @param ino the old inode number + * @param newparent inode number of the new parent directory + * @param newname new name to create + */ + void (*link) (fuse_req_t req, fuse_ino_t ino, fuse_ino_t newparent, + const char *newname); + + /** + * Open a file + * + * Open flags (with the exception of O_CREAT, O_EXCL, O_NOCTTY and + * O_TRUNC) are available in fi->flags. + * + * Filesystem may store an arbitrary file handle (pointer, index, + * etc) in fi->fh, and use this in other all other file operations + * (read, write, flush, release, fsync). + * + * Filesystem may also implement stateless file I/O and not store + * anything in fi->fh. + * + * There are also some flags (direct_io, keep_cache) which the + * filesystem may set in fi, to change the way the file is opened. + * See fuse_file_info structure in <fuse_common.h> for more details. + * + * Valid replies: + * fuse_reply_open + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + */ + void (*open) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi); + + /** + * Read data + * + * Read should send 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 file + * has been opened in 'direct_io' mode, in which case the return + * value of the read system call will reflect the return value of + * this operation. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * + * Valid replies: + * fuse_reply_buf + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param size number of bytes to read + * @param off offset to read from + * @param fi file information + */ + void (*read) (fuse_req_t req, fuse_ino_t ino, size_t size, off_t off, + struct fuse_file_info *fi); + + /** + * Write data + * + * Write should return exactly the number of bytes requested + * except on error. An exception to this is when the file has + * been opened in 'direct_io' mode, in which case the return value + * of the write system call will reflect the return value of this + * operation. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * + * Valid replies: + * fuse_reply_write + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param buf data to write + * @param size number of bytes to write + * @param off offset to write to + * @param fi file information + */ + void (*write) (fuse_req_t req, fuse_ino_t ino, const char *buf, + size_t size, off_t off, struct fuse_file_info *fi); + + /** + * Flush method + * + * This is called on each close() of the opened file. + * + * Since file descriptors can be duplicated (dup, dup2, fork), for + * one open call there may be many flush calls. + * + * Filesystems shouldn't assume that flush will always be called + * after some writes, or that if will be called at all. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * + * NOTE: the name of the method is misleading, since (unlike + * fsync) the filesystem is not forced to flush pending writes. + * One reason to flush data, is if the filesystem wants to return + * write errors. + * + * If the filesystem supports file locking operations (setlk, + * getlk) it should remove all locks belonging to 'fi->owner'. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + */ + void (*flush) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi); + + /** + * 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. + * + * The filesystem may reply with an error, but error values are + * not returned to close() or munmap() which triggered the + * release. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * fi->flags will contain the same flags as for open. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + */ + void (*release) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi); + + /** + * Synchronize file contents + * + * If the datasync parameter is non-zero, then only the user data + * should be flushed, not the meta data. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param datasync flag indicating if only data should be flushed + * @param fi file information + */ + void (*fsync) (fuse_req_t req, fuse_ino_t ino, int datasync, + struct fuse_file_info *fi); + + /** + * Open a directory + * + * Filesystem may store an arbitrary file handle (pointer, index, + * etc) in fi->fh, and use this in other all other directory + * stream operations (readdir, releasedir, fsyncdir). + * + * Filesystem may also implement stateless directory I/O and not + * store anything in fi->fh, though that makes it impossible to + * implement standard conforming directory stream operations in + * case the contents of the directory can change between opendir + * and releasedir. + * + * Valid replies: + * fuse_reply_open + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + */ + void (*opendir) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi); + + /** + * Read directory + * + * Send a buffer filled using fuse_add_direntry(), with size not + * exceeding the requested size. Send an empty buffer on end of + * stream. + * + * fi->fh will contain the value set by the opendir method, or + * will be undefined if the opendir method didn't set any value. + * + * Valid replies: + * fuse_reply_buf + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param size maximum number of bytes to send + * @param off offset to continue reading the directory stream + * @param fi file information + */ + void (*readdir) (fuse_req_t req, fuse_ino_t ino, size_t size, off_t off, + struct fuse_file_info *fi); + + /** + * Release an open directory + * + * For every opendir call there will be exactly one releasedir + * call. + * + * fi->fh will contain the value set by the opendir method, or + * will be undefined if the opendir method didn't set any value. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + */ + void (*releasedir) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi); + + /** + * Synchronize directory contents + * + * If the datasync parameter is non-zero, then only the directory + * contents should be flushed, not the meta data. + * + * fi->fh will contain the value set by the opendir method, or + * will be undefined if the opendir method didn't set any value. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param datasync flag indicating if only data should be flushed + * @param fi file information + */ + void (*fsyncdir) (fuse_req_t req, fuse_ino_t ino, int datasync, + struct fuse_file_info *fi); + + /** + * Get file system statistics + * + * Valid replies: + * fuse_reply_statfs + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number, zero means "undefined" + */ + void (*statfs) (fuse_req_t req, fuse_ino_t ino); + + /** + * Set an extended attribute + * + * Valid replies: + * fuse_reply_err + */ + void (*setxattr) (fuse_req_t req, fuse_ino_t ino, const char *name, + const char *value, size_t size, int flags); + + /** + * Get an extended attribute + * + * If size is zero, the size of the value should be sent with + * fuse_reply_xattr. + * + * If the size is non-zero, and the value fits in the buffer, the + * value should be sent with fuse_reply_buf. + * + * If the size is too small for the value, the ERANGE error should + * be sent. + * + * Valid replies: + * fuse_reply_buf + * fuse_reply_xattr + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param name of the extended attribute + * @param size maximum size of the value to send + */ + void (*getxattr) (fuse_req_t req, fuse_ino_t ino, const char *name, + size_t size); + + /** + * List extended attribute names + * + * If size is zero, the total size of the attribute list should be + * sent with fuse_reply_xattr. + * + * If the size is non-zero, and the null character separated + * attribute list fits in the buffer, the list should be sent with + * fuse_reply_buf. + * + * If the size is too small for the list, the ERANGE error should + * be sent. + * + * Valid replies: + * fuse_reply_buf + * fuse_reply_xattr + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param size maximum size of the list to send + */ + void (*listxattr) (fuse_req_t req, fuse_ino_t ino, size_t size); + + /** + * Remove an extended attribute + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param name of the extended attribute + */ + void (*removexattr) (fuse_req_t req, fuse_ino_t ino, const char *name); + + /** + * 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 + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param mask requested access mode + */ + void (*access) (fuse_req_t req, fuse_ino_t ino, int mask); + + /** + * Create and open a file + * + * If the file does not exist, first create it with the specified + * mode, and then open it. + * + * Open flags (with the exception of O_NOCTTY) are available in + * fi->flags. + * + * Filesystem may store an arbitrary file handle (pointer, index, + * etc) in fi->fh, and use this in other all other file operations + * (read, write, flush, release, fsync). + * + * There are also some flags (direct_io, keep_cache) which the + * filesystem may set in fi, to change the way the file is opened. + * See fuse_file_info structure in <fuse_common.h> for more details. + * + * 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 + * + * Valid replies: + * fuse_reply_create + * fuse_reply_err + * + * @param req request handle + * @param parent inode number of the parent directory + * @param name to create + * @param mode file type and mode with which to create the new file + * @param fi file information + */ + void (*create) (fuse_req_t req, fuse_ino_t parent, const char *name, + mode_t mode, struct fuse_file_info *fi); + + /** + * Test for a POSIX file lock + * + * Introduced in version 2.6 + * + * Valid replies: + * fuse_reply_lock + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + * @param lock the region/type to test + */ + void (*getlk) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi, struct flock *lock); + + /** + * Acquire, modify or release a POSIX file lock + * + * For POSIX threads (NPTL) there's a 1-1 relation between pid and + * owner, but otherwise this is not always the case. For checking + * lock ownership, 'fi->owner' must be used. The l_pid field in + * 'struct flock' should only be used to fill in this field in + * getlk(). + * + * Note: if the locking methods are not implemented, the kernel + * will still allow file locking to work locally. Hence these are + * only interesting for network filesystems and similar. + * + * Introduced in version 2.6 + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + * @param lock the region/type to test + * @param sleep locking operation may sleep + */ + void (*setlk) (fuse_req_t req, fuse_ino_t ino, + struct fuse_file_info *fi, + struct flock *lock, int sleep); + + /** + * 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 + * + * Valid replies: + * fuse_reply_bmap + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param blocksize unit of block index + * @param idx block index within file + */ + void (*bmap) (fuse_req_t req, fuse_ino_t ino, size_t blocksize, + uint64_t idx); +}; + +/** + * Reply with an error code or success + * + * Possible requests: + * all except forget + * + * unlink, rmdir, rename, flush, release, fsync, fsyncdir, setxattr, + * removexattr and setlk may send a zero code + * + * @param req request handle + * @param err the positive error value, or zero for success + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_err(fuse_req_t req, int err); + +/** + * Don't send reply + * + * Possible requests: + * forget + * + * @param req request handle + */ +void fuse_reply_none(fuse_req_t req); + +/** + * Reply with a directory entry + * + * Possible requests: + * lookup, mknod, mkdir, symlink, link + * + * @param req request handle + * @param e the entry parameters + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_entry(fuse_req_t req, const struct fuse_entry_param *e); + +/** + * Reply with a directory entry and open parameters + * + * currently the following members of 'fi' are used: + * fh, direct_io, keep_cache + * + * Possible requests: + * create + * + * @param req request handle + * @param e the entry parameters + * @param fi file information + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_create(fuse_req_t req, const struct fuse_entry_param *e, + const struct fuse_file_info *fi); + +/** + * Reply with attributes + * + * Possible requests: + * getattr, setattr + * + * @param req request handle + * @param the attributes + * @param attr_timeout validity timeout (in seconds) for the attributes + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_attr(fuse_req_t req, const struct stat *attr, + double attr_timeout); + +/** + * Reply with the contents of a symbolic link + * + * Possible requests: + * readlink + * + * @param req request handle + * @param link symbolic link contents + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_readlink(fuse_req_t req, const char *link); + +/** + * Reply with open parameters + * + * currently the following members of 'fi' are used: + * fh, direct_io, keep_cache + * + * Possible requests: + * open, opendir + * + * @param req request handle + * @param fi file information + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_open(fuse_req_t req, const struct fuse_file_info *fi); + +/** + * Reply with number of bytes written + * + * Possible requests: + * write + * + * @param req request handle + * @param count the number of bytes written + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_write(fuse_req_t req, size_t count); + +/** + * Reply with data + * + * Possible requests: + * read, readdir, getxattr, listxattr + * + * @param req request handle + * @param buf buffer containing data + * @param size the size of data in bytes + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_buf(fuse_req_t req, const char *buf, size_t size); + +#ifdef POSIXACLS +/** + * Reply with data vector + * + * Possible requests: + * read, readdir, getxattr, listxattr + * + * @param req request handle + * @param iov the vector containing the data + * @param count the size of vector + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_iov(fuse_req_t req, const struct iovec *iov, int count); +#endif + +/** + * Reply with filesystem statistics + * + * Possible requests: + * statfs + * + * @param req request handle + * @param stbuf filesystem statistics + * @return zero for success, -errno for failure to send reply + */ +#if HAVE_SYS_STATVFS_H +int fuse_reply_statfs(fuse_req_t req, const struct statvfs *stbuf); +#endif + + +/** + * Reply with needed buffer size + * + * Possible requests: + * getxattr, listxattr + * + * @param req request handle + * @param count the buffer size needed in bytes + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_xattr(fuse_req_t req, size_t count); + +/** + * Reply with file lock information + * + * Possible requests: + * getlk + * + * @param req request handle + * @param lock the lock information + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_lock(fuse_req_t req, struct flock *lock); + +/** + * Reply with block index + * + * Possible requests: + * bmap + * + * @param req request handle + * @param idx block index within device + * @return zero for success, -errno for failure to send reply + */ +int fuse_reply_bmap(fuse_req_t req, uint64_t idx); + +/* ----------------------------------------------------------- * + * Filling a buffer in readdir * + * ----------------------------------------------------------- */ + +/** + * Add a directory entry to the buffer + * + * Buffer needs to be large enough to hold the entry. Of it's not, + * then the entry is not filled in but the size of the entry is still + * returned. The caller can check this by comparing the bufsize + * parameter with the returned entry size. If the entry size is + * larger than the buffer size, the operation failed. + * + * From the 'stbuf' argument the st_ino field and bits 12-15 of the + * st_mode field are used. The other fields are ignored. + * + * Note: offsets do not necessarily represent physical offsets, and + * could be any marker, that enables the implementation to find a + * specific point in the directory stream. + * + * @param req request handle + * @param buf the point where the new entry will be added to the buffer + * @param bufsize remaining size of the buffer + * @param the name of the entry + * @param stbuf the file attributes + * @param off the offset of the next entry + * @return the space needed for the entry + */ +size_t fuse_add_direntry(fuse_req_t req, char *buf, size_t bufsize, + const char *name, const struct stat *stbuf, + off_t off); + +/* ----------------------------------------------------------- * + * Utility functions * + * ----------------------------------------------------------- */ + +/** + * Get the userdata from the request + * + * @param req request handle + * @return the user data passed to fuse_lowlevel_new() + */ +void *fuse_req_userdata(fuse_req_t req); + +/** + * Get the context from the request + * + * The pointer returned by this function will only be valid for the + * request's lifetime + * + * @param req request handle + * @return the context structure + */ +const struct fuse_ctx *fuse_req_ctx(fuse_req_t req); + +/** + * Callback function for an interrupt + * + * @param req interrupted request + * @param data user data + */ +typedef void (*fuse_interrupt_func_t)(fuse_req_t req, void *data); + +/** + * Register/unregister callback for an interrupt + * + * If an interrupt has already happened, then the callback function is + * called from within this function, hence it's not possible for + * interrupts to be lost. + * + * @param req request handle + * @param func the callback function or NULL for unregister + * @parm data user data passed to the callback function + */ +void fuse_req_interrupt_func(fuse_req_t req, fuse_interrupt_func_t func, + void *data); + +/** + * Check if a request has already been interrupted + * + * @param req request handle + * @return 1 if the request has been interrupted, 0 otherwise + */ +int fuse_req_interrupted(fuse_req_t req); + +/* ----------------------------------------------------------- * + * Filesystem setup * + * ----------------------------------------------------------- */ + +/** + * Create a low level session + * + * @param args argument vector + * @param op the low level filesystem operations + * @param op_size sizeof(struct fuse_lowlevel_ops) + * @param userdata user data + * @return the created session object, or NULL on failure + */ +struct fuse_session *fuse_lowlevel_new(struct fuse_args *args, + const struct fuse_lowlevel_ops *op, + size_t op_size, void *userdata); + +/* ----------------------------------------------------------- * + * Session interface * + * ----------------------------------------------------------- */ + +/** + * Session operations + * + * This is used in session creation + */ +struct fuse_session_ops { + /** + * Hook to process a request (mandatory) + * + * @param data user data passed to fuse_session_new() + * @param buf buffer containing the raw request + * @param len request length + * @param ch channel on which the request was received + */ + void (*process) (void *data, const char *buf, size_t len, + struct fuse_chan *ch); + + /** + * Hook for session exit and reset (optional) + * + * @param data user data passed to fuse_session_new() + * @param val exited status (1 - exited, 0 - not exited) + */ + void (*exit) (void *data, int val); + + /** + * Hook for querying the current exited status (optional) + * + * @param data user data passed to fuse_session_new() + * @return 1 if exited, 0 if not exited + */ + int (*exited) (void *data); + + /** + * Hook for cleaning up the channel on destroy (optional) + * + * @param data user data passed to fuse_session_new() + */ + void (*destroy) (void *data); +}; + +/** + * Create a new session + * + * @param op session operations + * @param data user data + * @return new session object, or NULL on failure + */ +struct fuse_session *fuse_session_new(struct fuse_session_ops *op, void *data); + +/** + * Assign a channel to a session + * + * Note: currently only a single channel may be assigned. This may + * change in the future + * + * If a session is destroyed, the assigned channel is also destroyed + * + * @param se the session + * @param ch the channel + */ +void fuse_session_add_chan(struct fuse_session *se, struct fuse_chan *ch); + +/** + * Remove a channel from a session + * + * If the channel is not assigned to a session, then this is a no-op + * + * @param ch the channel to remove + */ +void fuse_session_remove_chan(struct fuse_chan *ch); + +/** + * Iterate over the channels assigned to a session + * + * The iterating function needs to start with a NULL channel, and + * after that needs to pass the previously returned channel to the + * function. + * + * @param se the session + * @param ch the previous channel, or NULL + * @return the next channel, or NULL if no more channels exist + */ +struct fuse_chan *fuse_session_next_chan(struct fuse_session *se, + struct fuse_chan *ch); + +/** + * Process a raw request + * + * @param se the session + * @param buf buffer containing the raw request + * @param len request length + * @param ch channel on which the request was received + */ +void fuse_session_process(struct fuse_session *se, const char *buf, size_t len, + struct fuse_chan *ch); + +/** + * Destroy a session + * + * @param se the session + */ +void fuse_session_destroy(struct fuse_session *se); + +/** + * Exit a session + * + * @param se the session + */ +void fuse_session_exit(struct fuse_session *se); + +/** + * Reset the exited status of a session + * + * @param se the session + */ +void fuse_session_reset(struct fuse_session *se); + +/** + * Query the exited status of a session + * + * @param se the session + * @return 1 if exited, 0 if not exited + */ +int fuse_session_exited(struct fuse_session *se); + +/** + * Enter a single threaded event loop + * + * @param se the session + * @return 0 on success, -1 on error + */ +int fuse_session_loop(struct fuse_session *se); + +/** + * Enter a multi-threaded event loop + * + * @param se the session + * @return 0 on success, -1 on error + */ +int fuse_session_loop_mt(struct fuse_session *se); + +/* ----------------------------------------------------------- * + * Channel interface * + * ----------------------------------------------------------- */ + +/** + * Channel operations + * + * This is used in channel creation + */ +struct fuse_chan_ops { + /** + * Hook for receiving a raw request + * + * @param ch pointer to the channel + * @param buf the buffer to store the request in + * @param size the size of the buffer + * @return the actual size of the raw request, or -1 on error + */ + int (*receive)(struct fuse_chan **chp, char *buf, size_t size); + + /** + * Hook for sending a raw reply + * + * A return value of -ENOENT means, that the request was + * interrupted, and the reply was discarded + * + * @param ch the channel + * @param iov vector of blocks + * @param count the number of blocks in vector + * @return zero on success, -errno on failure + */ + int (*send)(struct fuse_chan *ch, const struct iovec iov[], + size_t count); + + /** + * Destroy the channel + * + * @param ch the channel + */ + void (*destroy)(struct fuse_chan *ch); +}; + +/** + * Create a new channel + * + * @param op channel operations + * @param fd file descriptor of the channel + * @param bufsize the minimal receive buffer size + * @param data user data + * @return the new channel object, or NULL on failure + */ +struct fuse_chan *fuse_chan_new(struct fuse_chan_ops *op, int fd, + size_t bufsize, void *data); + +/** + * Query the file descriptor of the channel + * + * @param ch the channel + * @return the file descriptor passed to fuse_chan_new() + */ +int fuse_chan_fd(struct fuse_chan *ch); + +/** + * Query the minimal receive buffer size + * + * @param ch the channel + * @return the buffer size passed to fuse_chan_new() + */ +size_t fuse_chan_bufsize(struct fuse_chan *ch); + +/** + * Query the user data + * + * @param ch the channel + * @return the user data passed to fuse_chan_new() + */ +void *fuse_chan_data(struct fuse_chan *ch); + +/** + * Query the session to which this channel is assigned + * + * @param ch the channel + * @return the session, or NULL if the channel is not assigned + */ +struct fuse_session *fuse_chan_session(struct fuse_chan *ch); + +/** + * Receive a raw request + * + * A return value of -ENODEV means, that the filesystem was unmounted + * + * @param ch pointer to the channel + * @param buf the buffer to store the request in + * @param size the size of the buffer + * @return the actual size of the raw request, or -errno on error + */ +int fuse_chan_recv(struct fuse_chan **ch, char *buf, size_t size); + +/** + * Send a raw reply + * + * A return value of -ENOENT means, that the request was + * interrupted, and the reply was discarded + * + * @param ch the channel + * @param iov vector of blocks + * @param count the number of blocks in vector + * @return zero on success, -errno on failure + */ +int fuse_chan_send(struct fuse_chan *ch, const struct iovec iov[], + size_t count); + +/** + * Destroy a channel + * + * @param ch the channel + */ +void fuse_chan_destroy(struct fuse_chan *ch); + +#ifdef __cplusplus +} +#endif + +#endif /* _FUSE_LOWLEVEL_H_ */ |