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qemu-kvm/SOURCES/kvm-virtiofsd-Pull-in-upstream-headers.patch

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import qemu-kvm-4.2.0-34.module+el8.3.0+9828+7aab3355.3
2021-02-16 07:43:20 +00:00
From 434b51e5c2fce756906dec4803900397bc98ad72 Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Date: Mon, 27 Jan 2020 19:00:39 +0100
Subject: [PATCH 008/116] virtiofsd: Pull in upstream headers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: <20200127190227.40942-5-dgilbert@redhat.com>
Patchwork-id: 93457
O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 004/112] virtiofsd: Pull in upstream headers
Bugzilla: 1694164
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Pull in headers fromlibfuse's upstream fuse-3.8.0
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit ee46c78901eb7fa78e328e04c0494ad6d207238b)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
tools/virtiofsd/fuse.h | 1275 ++++++++++++++++++++
tools/virtiofsd/fuse_common.h | 823 +++++++++++++
tools/virtiofsd/fuse_i.h | 139 +++
tools/virtiofsd/fuse_log.h | 82 ++
tools/virtiofsd/fuse_lowlevel.h | 2089 +++++++++++++++++++++++++++++++++
tools/virtiofsd/fuse_misc.h | 59 +
tools/virtiofsd/fuse_opt.h | 271 +++++
tools/virtiofsd/passthrough_helpers.h | 76 ++
8 files changed, 4814 insertions(+)
create mode 100644 tools/virtiofsd/fuse.h
create mode 100644 tools/virtiofsd/fuse_common.h
create mode 100644 tools/virtiofsd/fuse_i.h
create mode 100644 tools/virtiofsd/fuse_log.h
create mode 100644 tools/virtiofsd/fuse_lowlevel.h
create mode 100644 tools/virtiofsd/fuse_misc.h
create mode 100644 tools/virtiofsd/fuse_opt.h
create mode 100644 tools/virtiofsd/passthrough_helpers.h
diff --git a/tools/virtiofsd/fuse.h b/tools/virtiofsd/fuse.h
new file mode 100644
index 0000000..883f6e5
--- /dev/null
+++ b/tools/virtiofsd/fuse.h
@@ -0,0 +1,1275 @@
+/*
+ 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 <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;
+
+/**
+ * Readdir flags, passed to ->readdir()
+ */
+enum fuse_readdir_flags {
+ /**
+ * "Plus" mode.
+ *
+ * The kernel wants to prefill the inode cache during readdir. The
+ * filesystem may honour this by filling in the attributes and setting
+ * FUSE_FILL_DIR_FLAGS for the filler function. The filesystem may also
+ * just ignore this flag completely.
+ */
+ FUSE_READDIR_PLUS = (1 << 0),
+};
+
+enum fuse_fill_dir_flags {
+ /**
+ * "Plus" mode: all file attributes are valid
+ *
+ * The attributes are used by the kernel to prefill the inode cache
+ * during a readdir.
+ *
+ * It is okay to set FUSE_FILL_DIR_PLUS if FUSE_READDIR_PLUS is not set
+ * and vice versa.
+ */
+ FUSE_FILL_DIR_PLUS = (1 << 1),
+};
+
+/** Function to add an entry in a readdir() operation
+ *
+ * The *off* parameter can be any non-zero value that enables the
+ * filesystem to identify the current point in the directory
+ * stream. It does not need to be the actual physical position. A
+ * value of zero is reserved to indicate that seeking in directories
+ * is not supported.
+ *
+ * @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
+ * @param flags fill flags
+ * @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,
+ enum fuse_fill_dir_flags flags);
+/**
+ * Configuration of the high-level API
+ *
+ * This structure is initialized from the arguments passed to
+ * fuse_new(), and then passed to the file system's init() handler
+ * which should ensure that the configuration is compatible with the
+ * file system implementation.
+ */
+struct fuse_config {
+ /**
+ * If `set_gid` is non-zero, the st_gid attribute of each file
+ * is overwritten with the value of `gid`.
+ */
+ int set_gid;
+ unsigned int gid;
+
+ /**
+ * If `set_uid` is non-zero, the st_uid attribute of each file
+ * is overwritten with the value of `uid`.
+ */
+ int set_uid;
+ unsigned int uid;
+
+ /**
+ * If `set_mode` is non-zero, the any permissions bits set in
+ * `umask` are unset in the st_mode attribute of each file.
+ */
+ int set_mode;
+ unsigned int umask;
+
+ /**
+ * The timeout in seconds for which name lookups will be
+ * cached.
+ */
+ double entry_timeout;
+
+ /**
+ * The timeout in seconds for which a negative lookup will be
+ * cached. This means, that if file did not exist (lookup
+ * retuned ENOENT), the lookup will only be redone after the
+ * timeout, and the file/directory will be assumed to not
+ * exist until then. A value of zero means that negative
+ * lookups are not cached.
+ */
+ double negative_timeout;
+
+ /**
+ * The timeout in seconds for which file/directory attributes
+ * (as returned by e.g. the `getattr` handler) are cached.
+ */
+ double attr_timeout;
+
+ /**
+ * Allow requests to be interrupted
+ */
+ int intr;
+
+ /**
+ * Specify which signal number to send to the filesystem when
+ * a request is interrupted. The default is hardcoded to
+ * USR1.
+ */
+ int intr_signal;
+
+ /**
+ * Normally, FUSE assigns inodes to paths only for as long as
+ * the kernel is aware of them. With this option inodes are
+ * instead remembered for at least this many seconds. This
+ * will require more memory, but may be necessary when using
+ * applications that make use of inode numbers.
+ *
+ * A number of -1 means that inodes will be remembered for the
+ * entire life-time of the file-system process.
+ */
+ int remember;
+
+ /**
+ * The default behavior is that if an open file is deleted,
+ * the file is renamed to a hidden file (.fuse_hiddenXXX), and
+ * only removed when the file is finally released. This
+ * relieves the filesystem implementation of having to deal
+ * with this problem. This option disables the hiding
+ * behavior, and files are removed immediately in an unlink
+ * operation (or in a rename operation which overwrites an
+ * existing file).
+ *
+ * It is recommended that you not use the hard_remove
+ * option. When hard_remove is set, the following libc
+ * functions fail on unlinked files (returning errno of
+ * ENOENT): read(2), write(2), fsync(2), close(2), f*xattr(2),
+ * ftruncate(2), fstat(2), fchmod(2), fchown(2)
+ */
+ int hard_remove;
+
+ /**
+ * Honor the st_ino field in the functions getattr() and
+ * fill_dir(). This value is used to fill in the st_ino field
+ * in the stat(2), lstat(2), fstat(2) functions and the d_ino
+ * field in the readdir(2) function. The filesystem does not
+ * have to guarantee uniqueness, however some applications
+ * rely on this value being unique for the whole filesystem.
+ *
+ * Note that this does *not* affect the inode that libfuse
+ * and the kernel use internally (also called the "nodeid").
+ */
+ int use_ino;
+
+ /**
+ * If use_ino option is not given, still try to fill in the
+ * d_ino field in readdir(2). If the name was previously
+ * looked up, and is still in the cache, the inode number
+ * found there will be used. Otherwise it will be set to -1.
+ * If use_ino option is given, this option is ignored.
+ */
+ int readdir_ino;
+
+ /**
+ * This option disables the use of page cache (file content cache)
+ * in the kernel for this filesystem. This has several affects:
+ *
+ * 1. Each read(2) or write(2) system call will initiate one
+ * or more read or write operations, data will not be
+ * cached in the kernel.
+ *
+ * 2. The return value of the read() and write() system calls
+ * will correspond to the return values of the read and
+ * write operations. This is useful for example if the
+ * file size is not known in advance (before reading it).
+ *
+ * Internally, enabling this option causes fuse to set the
+ * `direct_io` field of `struct fuse_file_info` - overwriting
+ * any value that was put there by the file system.
+ */
+ int direct_io;
+
+ /**
+ * This option disables flushing the cache of the file
+ * contents on every open(2). This should only be enabled on
+ * filesystems where the file data is never changed
+ * externally (not through the mounted FUSE filesystem). Thus
+ * it is not suitable for network filesystems and other
+ * intermediate filesystems.
+ *
+ * NOTE: if this option is not specified (and neither
+ * direct_io) data is still cached after the open(2), so a
+ * read(2) system call will not always initiate a read
+ * operation.
+ *
+ * Internally, enabling this option causes fuse to set the
+ * `keep_cache` field of `struct fuse_file_info` - overwriting
+ * any value that was put there by the file system.
+ */
+ int kernel_cache;
+
+ /**
+ * This option is an alternative to `kernel_cache`. Instead of
+ * unconditionally keeping cached data, the cached data is
+ * invalidated on open(2) if if the modification time or the
+ * size of the file has changed since it was last opened.
+ */
+ int auto_cache;
+
+ /**
+ * The timeout in seconds for which file attributes are cached
+ * for the purpose of checking if auto_cache should flush the
+ * file data on open.
+ */
+ int ac_attr_timeout_set;
+ double ac_attr_timeout;
+
+ /**
+ * If this option is given the file-system handlers for the
+ * following operations will not receive path information:
+ * read, write, flush, release, fsync, readdir, releasedir,
+ * fsyncdir, lock, ioctl and poll.
+ *
+ * For the truncate, getattr, chmod, chown and utimens
+ * operations the path will be provided only if the struct
+ * fuse_file_info argument is NULL.
+ */
+ int nullpath_ok;
+
+ /**
+ * The remaining options are used by libfuse internally and
+ * should not be touched.
+ */
+ int show_help;
+ char *modules;
+ int debug;
+};
+
+
+/**
+ * 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, truncate, lock, init and
+ * destroy are special purpose methods, without which a full featured
+ * filesystem can still be implemented.
+ *
+ * In general, all methods are expected to perform any necessary
+ * permission checking. However, a filesystem may delegate this task
+ * to the kernel by passing the `default_permissions` mount option to
+ * `fuse_new()`. In this case, methods will only be called if
+ * the kernel's permission check has succeeded.
+ *
+ * Almost all operations take a path which can be of any length.
+ */
+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. In that case it is passed to userspace,
+ * but libfuse and the kernel will still assign a different
+ * inode for internal use (called the "nodeid").
+ *
+ * `fi` will always be NULL if the file is not currently open, but
+ * may also be NULL if the file is open.
+ */
+ int (*getattr) (const char *, struct stat *, struct fuse_file_info *fi);
+
+ /** 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);
+
+ /** 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
+ *
+ * *flags* may be `RENAME_EXCHANGE` or `RENAME_NOREPLACE`. If
+ * RENAME_NOREPLACE is specified, the filesystem must not
+ * overwrite *newname* if it exists and return an error
+ * instead. If `RENAME_EXCHANGE` is specified, the filesystem
+ * must atomically exchange the two files, i.e. both must
+ * exist and neither may be deleted.
+ */
+ int (*rename) (const char *, const char *, unsigned int flags);
+
+ /** Create a hard link to a file */
+ int (*link) (const char *, const char *);
+
+ /** Change the permission bits of a file
+ *
+ * `fi` will always be NULL if the file is not currenlty open, but
+ * may also be NULL if the file is open.
+ */
+ int (*chmod) (const char *, mode_t, struct fuse_file_info *fi);
+
+ /** Change the owner and group of a file
+ *
+ * `fi` will always be NULL if the file is not currenlty open, but
+ * may also be NULL if the file is open.
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits.
+ */
+ int (*chown) (const char *, uid_t, gid_t, struct fuse_file_info *fi);
+
+ /** Change the size of a file
+ *
+ * `fi` will always be NULL if the file is not currenlty open, but
+ * may also be NULL if the file is open.
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits.
+ */
+ int (*truncate) (const char *, off_t, struct fuse_file_info *fi);
+
+ /** Open a file
+ *
+ * Open flags are available in fi->flags. The following rules
+ * apply.
+ *
+ * - Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be
+ * filtered out / handled by the kernel.
+ *
+ * - Access modes (O_RDONLY, O_WRONLY, O_RDWR, O_EXEC, O_SEARCH)
+ * should be used by the filesystem to check if the operation is
+ * permitted. If the ``-o default_permissions`` mount option is
+ * given, this check is already done by the kernel before calling
+ * open() and may thus be omitted by the filesystem.
+ *
+ * - When writeback caching is enabled, the kernel may send
+ * read requests even for files opened with O_WRONLY. The
+ * filesystem should be prepared to handle this.
+ *
+ * - When writeback caching is disabled, the filesystem is
+ * expected to properly handle the O_APPEND flag and ensure
+ * that each write is appending to the end of the file.
+ *
+ * - When writeback caching is enabled, the kernel will
+ * handle O_APPEND. However, unless all changes to the file
+ * come through the kernel this will not work reliably. The
+ * filesystem should thus either ignore the O_APPEND flag
+ * (and let the kernel handle it), or return an error
+ * (indicating that reliably O_APPEND is not available).
+ *
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS
+ * and FUSE_CAP_NO_OPEN_SUPPORT is set in
+ * `fuse_conn_info.capable`, this is treated as success and
+ * future calls to open will also succeed without being send
+ * to the filesystem process.
+ *
+ */
+ 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.
+ */
+ 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).
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits.
+ */
+ int (*write) (const char *, const char *, size_t, off_t,
+ struct fuse_file_info *);
+
+ /** Get file system statistics
+ *
+ * The 'f_favail', 'f_fsid' and 'f_flag' fields are ignored
+ */
+ 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, as opposed to
+ * release which is called on the close of the last file descriptor for
+ * a file. Under Linux, errors returned by flush() will be passed to
+ * userspace as errors from close(), so flush() is a good place to write
+ * back any cached dirty data. However, many applications ignore errors
+ * on close(), and on non-Linux systems, close() may succeed even if flush()
+ * returns an error. For these reasons, filesystems should not assume
+ * that errors returned by flush will ever be noticed or even
+ * delivered.
+ *
+ * NOTE: The flush() method may be called more than once for each
+ * open(). This happens if more than one file descriptor refers to an
+ * open file handle, e.g. 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 be called at any
+ * particular point. It may be called more times than expected, or not
+ * at all.
+ *
+ * [close]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/close.html
+ */
+ 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 handle. 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.
+ */
+ 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.
+ */
+ 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, releasedir and fsyncdir.
+ */
+ int (*opendir) (const char *, struct fuse_file_info *);
+
+ /** Read directory
+ *
+ * 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.
+ *
+ * 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'.
+ */
+ int (*readdir) (const char *, void *, fuse_fill_dir_t, off_t,
+ struct fuse_file_info *, enum fuse_readdir_flags);
+
+ /** Release directory
+ */
+ 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
+ */
+ int (*fsyncdir) (const char *, int, struct fuse_file_info *);
+
+ /**
+ * Initialize filesystem
+ *
+ * The return value will passed in the `private_data` field of
+ * `struct fuse_context` to all file operations, and as a
+ * parameter to the destroy() method. It overrides the initial
+ * value provided to fuse_main() / fuse_new().
+ */
+ void *(*init) (struct fuse_conn_info *conn,
+ struct fuse_config *cfg);
+
+ /**
+ * Clean up filesystem
+ *
+ * Called on filesystem exit.
+ */
+ void (*destroy) (void *private_data);
+
+ /**
+ * 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
+ */
+ 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.
+ */
+ int (*create) (const char *, mode_t, 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.
+ */
+ 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.
+ *
+ * `fi` will always be NULL if the file is not currenlty open, but
+ * may also be NULL if the file is open.
+ *
+ * See the utimensat(2) man page for details.
+ */
+ int (*utimens) (const char *, const struct timespec tv[2],
+ struct fuse_file_info *fi);
+
+ /**
+ * 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
+ */
+ 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.
+ *
+ * If flags has FUSE_IOCTL_DIR then the fuse_file_info refers to a
+ * directory file handle.
+ *
+ * Note : the unsigned long request submitted by the application
+ * is truncated to 32 bits.
+ */
+ int (*ioctl) (const char *, unsigned 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.
+ */
+ 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.
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits.
+ */
+ 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.
+ */
+ 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.
+ */
+ 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.
+ */
+ int (*fallocate) (const char *, int, off_t, off_t,
+ struct fuse_file_info *);
+
+ /**
+ * Copy a range of data from one file to another
+ *
+ * Performs an optimized copy between two file descriptors without the
+ * additional cost of transferring data through the FUSE kernel module
+ * to user space (glibc) and then back into the FUSE filesystem again.
+ *
+ * In case this method is not implemented, glibc falls back to reading
+ * data from the source and writing to the destination. Effectively
+ * doing an inefficient copy of the data.
+ */
+ ssize_t (*copy_file_range) (const char *path_in,
+ struct fuse_file_info *fi_in,
+ off_t offset_in, const char *path_out,
+ struct fuse_file_info *fi_out,
+ off_t offset_out, size_t size, int flags);
+
+ /**
+ * Find next data or hole after the specified offset
+ */
+ off_t (*lseek) (const char *, off_t off, int whence, 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;
+
+ /** Process ID of the calling thread */
+ pid_t pid;
+
+ /** Private filesystem data */
+ void *private_data;
+
+ /** Umask of the calling process */
+ 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, and handles --help and
+ * --version
+ * - 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
+ *
+ * Most file systems will have to parse some file-system specific
+ * arguments before calling this function. It is recommended to do
+ * this with fuse_opt_parse() and a processing function that passes
+ * through any unknown options (this can also be achieved by just
+ * passing NULL as the processing function). That way, the remaining
+ * options can be passed directly to fuse_main().
+ *
+ * fuse_main() accepts all options that can be passed to
+ * fuse_parse_cmdline(), fuse_new(), or fuse_session_new().
+ *
+ * Option parsing skips argv[0], which is assumed to contain the
+ * program name. This element must always be present and is used to
+ * construct a basic ``usage: `` message for the --help
+ * output. argv[0] may also be set to the empty string. In this case
+ * the usage message is suppressed. This can be used by file systems
+ * to print their own usage line first. See hello.c for an example of
+ * how to do this.
+ *
+ * Note: this is currently implemented as a macro.
+ *
+ * The following error codes may be returned from fuse_main():
+ * 1: Invalid option arguments
+ * 2: No mount point specified
+ * 3: FUSE setup failed
+ * 4: Mounting failed
+ * 5: Failed to daemonize (detach from session)
+ * 6: Failed to set up signal handlers
+ * 7: An error occured during the life of the file system
+ *
+ * @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 private_data Initial value for the `private_data`
+ * field of `struct fuse_context`. May be overridden by the
+ * `struct fuse_operations.init` handler.
+ * @return 0 on success, nonzero on failure
+ *
+ * Example usage, see hello.c
+ */
+/*
+ int fuse_main(int argc, char *argv[], const struct fuse_operations *op,
+ void *private_data);
+*/
+#define fuse_main(argc, argv, op, private_data) \
+ fuse_main_real(argc, argv, op, sizeof(*(op)), private_data)
+
+/* ----------------------------------------------------------- *
+ * More detailed API *
+ * ----------------------------------------------------------- */
+
+/**
+ * Print available options (high- and low-level) to stdout. This is
+ * not an exhaustive list, but includes only those options that may be
+ * of interest to an end-user of a file system.
+ *
+ * The function looks at the argument vector only to determine if
+ * there are additional modules to be loaded (module=foo option),
+ * and attempts to call their help functions as well.
+ *
+ * @param args the argument vector.
+ */
+void fuse_lib_help(struct fuse_args *args);
+
+/**
+ * Create a new FUSE filesystem.
+ *
+ * This function accepts most file-system independent mount options
+ * (like context, nodev, ro - see mount(8)), as well as the
+ * FUSE-specific mount options from mount.fuse(8).
+ *
+ * If the --help option is specified, the function writes a help text
+ * to stdout and returns NULL.
+ *
+ * Option parsing skips argv[0], which is assumed to contain the
+ * program name. This element must always be present and is used to
+ * construct a basic ``usage: `` message for the --help output. If
+ * argv[0] is set to the empty string, no usage message is included in
+ * the --help output.
+ *
+ * If an unknown option is passed in, an error message is written to
+ * stderr and the function returns NULL.
+ *
+ * @param args argument vector
+ * @param op the filesystem operations
+ * @param op_size the size of the fuse_operations structure
+ * @param private_data Initial value for the `private_data`
+ * field of `struct fuse_context`. May be overridden by the
+ * `struct fuse_operations.init` handler.
+ * @return the created FUSE handle
+ */
+#if FUSE_USE_VERSION == 30
+struct fuse *fuse_new_30(struct fuse_args *args, const struct fuse_operations *op,
+ size_t op_size, void *private_data);
+#define fuse_new(args, op, size, data) fuse_new_30(args, op, size, data)
+#else
+struct fuse *fuse_new(struct fuse_args *args, const struct fuse_operations *op,
+ size_t op_size, void *private_data);
+#endif
+
+/**
+ * Mount a FUSE file system.
+ *
+ * @param mountpoint the mount point path
+ * @param f the FUSE handle
+ *
+ * @return 0 on success, -1 on failure.
+ **/
+int fuse_mount(struct fuse *f, const char *mountpoint);
+
+/**
+ * Unmount a FUSE file system.
+ *
+ * See fuse_session_unmount() for additional information.
+ *
+ * @param f the FUSE handle
+ **/
+void fuse_unmount(struct fuse *f);
+
+/**
+ * Destroy the FUSE handle.
+ *
+ * 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.
+ *
+ * For a description of the return value and the conditions when the
+ * event loop exits, refer to the documentation of
+ * fuse_session_loop().
+ *
+ * @param f the FUSE handle
+ * @return see fuse_session_loop()
+ *
+ * See also: fuse_loop_mt()
+ */
+int fuse_loop(struct fuse *f);
+
+/**
+ * Flag session as terminated
+ *
+ * This function will cause any running event loops to exit on
+ * the next opportunity.
+ *
+ * @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.
+ *
+ * For a description of the return value and the conditions when the
+ * event loop exits, refer to the documentation of
+ * fuse_session_loop().
+ *
+ * Note: using fuse_loop() instead of fuse_loop_mt() means you are running in
+ * single-threaded mode, and that you will not have to worry about reentrancy,
+ * though you will have to worry about recursive lookups. In single-threaded
+ * mode, FUSE will wait for one callback to return before calling another.
+ *
+ * Enabling multiple threads, by using fuse_loop_mt(), will cause FUSE to make
+ * multiple simultaneous calls into the various callback functions given by your
+ * fuse_operations record.
+ *
+ * If you are using multiple threads, you can enjoy all the parallel execution
+ * and interactive response benefits of threads, and you get to enjoy all the
+ * benefits of race conditions and locking bugs, too. Ensure that any code used
+ * in the callback function of fuse_operations is also thread-safe.
+ *
+ * @param f the FUSE handle
+ * @param config loop configuration
+ * @return see fuse_session_loop()
+ *
+ * See also: fuse_loop()
+ */
+#if FUSE_USE_VERSION < 32
+int fuse_loop_mt_31(struct fuse *f, int clone_fd);
+#define fuse_loop_mt(f, clone_fd) fuse_loop_mt_31(f, clone_fd)
+#else
+int fuse_loop_mt(struct fuse *f, struct fuse_loop_config *config);
+#endif
+
+/**
+ * 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);
+
+/**
+ * Invalidates cache for the given path.
+ *
+ * This calls fuse_lowlevel_notify_inval_inode internally.
+ *
+ * @return 0 on successful invalidation, negative error value otherwise.
+ * This routine may return -ENOENT to indicate that there was
+ * no entry to be invalidated, e.g., because the path has not
+ * been seen before or has been forgotten; this should not be
+ * considered to be an error.
+ */
+int fuse_invalidate_path(struct fuse *f, const char *path);
+
+/**
+ * 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 *private_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,
+ struct fuse_file_info *fi);
+int fuse_fs_rename(struct fuse_fs *fs, const char *oldpath,
+ const char *newpath, unsigned int flags);
+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, enum fuse_readdir_flags flags);
+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,
+ struct fuse_file_info *fi);
+int fuse_fs_chown(struct fuse_fs *fs, const char *path, uid_t uid, gid_t gid,
+ struct fuse_file_info *fi);
+int fuse_fs_truncate(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], struct fuse_file_info *fi);
+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, unsigned 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);
+ssize_t fuse_fs_copy_file_range(struct fuse_fs *fs, const char *path_in,
+ struct fuse_file_info *fi_in, off_t off_in,
+ const char *path_out,
+ struct fuse_file_info *fi_out, off_t off_out,
+ size_t len, int flags);
+off_t fuse_fs_lseek(struct fuse_fs *fs, const char *path, off_t off, int whence,
+ struct fuse_file_info *fi);
+void fuse_fs_init(struct fuse_fs *fs, struct fuse_conn_info *conn,
+ struct fuse_config *cfg);
+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 private_data Initial value for the `private_data`
+ * field of `struct fuse_context`. May be overridden by the
+ * `struct fuse_operations.init` handler.
+ * @return a new filesystem object
+ */
+struct fuse_fs *fuse_fs_new(const struct fuse_operations *op, size_t op_size,
+ void *private_data);
+
+/**
+ * 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
+ */
+typedef struct fuse_fs *(*fuse_module_factory_t)(struct fuse_args *args,
+ struct fuse_fs *fs[]);
+/**
+ * Register filesystem module
+ *
+ * If the "-omodules=*name*_:..." option is present, filesystem
+ * objects are created and pushed onto the stack with the *factory_*
+ * function.
+ *
+ * @param name_ the name of this filesystem module
+ * @param factory_ the factory function for this filesystem module
+ */
+#define FUSE_REGISTER_MODULE(name_, factory_) \
+ fuse_module_factory_t fuse_module_ ## name_ ## _factory = factory_
+
+/** Get session from fuse object */
+struct fuse_session *fuse_get_session(struct fuse *f);
+
+/**
+ * Open a FUSE file descriptor and set up the mount for the given
+ * mountpoint and flags.
+ *
+ * @param mountpoint reference to the mount in the file system
+ * @param options mount options
+ * @return the FUSE file descriptor or -1 upon error
+ */
+int fuse_open_channel(const char *mountpoint, const char *options);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* FUSE_H_ */
diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
new file mode 100644
index 0000000..2d686b2
--- /dev/null
+++ b/tools/virtiofsd/fuse_common.h
@@ -0,0 +1,823 @@
+/* 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.
+*/
+
+/** @file */
+
+#if !defined(FUSE_H_) && !defined(FUSE_LOWLEVEL_H_)
+#error "Never include <fuse_common.h> directly; use <fuse.h> or <fuse_lowlevel.h> instead."
+#endif
+
+#ifndef FUSE_COMMON_H_
+#define FUSE_COMMON_H_
+
+#include "fuse_opt.h"
+#include "fuse_log.h"
+#include <stdint.h>
+#include <sys/types.h>
+
+/** Major version of FUSE library interface */
+#define FUSE_MAJOR_VERSION 3
+
+/** Minor version of FUSE library interface */
+#define FUSE_MINOR_VERSION 2
+
+#define FUSE_MAKE_VERSION(maj, min) ((maj) * 10 + (min))
+#define FUSE_VERSION FUSE_MAKE_VERSION(FUSE_MAJOR_VERSION, FUSE_MINOR_VERSION)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Information about an open file.
+ *
+ * File Handles are created by the open, opendir, and create methods and closed
+ * by the release and releasedir methods. Multiple file handles may be
+ * concurrently open for the same file. Generally, a client will create one
+ * file handle per file descriptor, though in some cases multiple file
+ * descriptors can share a single file handle.
+ */
+struct fuse_file_info {
+ /** Open flags. Available in open() and release() */
+ int flags;
+
+ /** In case of a write operation indicates if this was caused
+ by a delayed write from the page cache. If so, then the
+ context's pid, uid, and gid fields will not be valid, and
+ the *fh* value may not match the *fh* value that would
+ have been sent with the corresponding individual write
+ requests if write caching had been disabled. */
+ unsigned int writepage : 1;
+
+ /** Can be filled in by open, to use direct I/O on this file. */
+ unsigned int direct_io : 1;
+
+ /** Can be filled in by open. It signals the kernel that any
+ currently cached file data (ie., data that the filesystem
+ provided the last time the file was open) need not be
+ invalidated. Has no effect when set in other contexts (in
+ particular it does nothing when set by opendir()). */
+ unsigned int keep_cache : 1;
+
+ /** Indicates a flush operation. Set in flush operation, also
+ maybe set in highlevel lock operation and lowlevel release
+ operation. */
+ unsigned int flush : 1;
+
+ /** Can be filled in by open, to indicate that the file is not
+ seekable. */
+ unsigned int nonseekable : 1;
+
+ /* Indicates that flock locks for this file should be
+ released. If set, lock_owner shall contain a valid value.
+ May only be set in ->release(). */
+ unsigned int flock_release : 1;
+
+ /** Can be filled in by opendir. It signals the kernel to
+ enable caching of entries returned by readdir(). Has no
+ effect when set in other contexts (in particular it does
+ nothing when set by open()). */
+ unsigned int cache_readdir : 1;
+
+ /** Padding. Reserved for future use*/
+ unsigned int padding : 25;
+ unsigned int padding2 : 32;
+
+ /** File handle id. May be filled in by filesystem in create,
+ * open, and opendir(). Available in most other file operations on the
+ * same file handle. */
+ uint64_t fh;
+
+ /** Lock owner id. Available in locking operations and flush */
+ uint64_t lock_owner;
+
+ /** Requested poll events. Available in ->poll. Only set on kernels
+ which support it. If unsupported, this field is set to zero. */
+ uint32_t poll_events;
+};
+
+/**
+ * Configuration parameters passed to fuse_session_loop_mt() and
+ * fuse_loop_mt().
+ */
+struct fuse_loop_config {
+ /**
+ * whether to use separate device fds for each thread
+ * (may increase performance)
+ */
+ int clone_fd;
+
+ /**
+ * The maximum number of available worker threads before they
+ * start to get deleted when they become idle. If not
+ * specified, the default is 10.
+ *
+ * Adjusting this has performance implications; a very small number
+ * of threads in the pool will cause a lot of thread creation and
+ * deletion overhead and performance may suffer. When set to 0, a new
+ * thread will be created to service every operation.
+ */
+ unsigned int max_idle_threads;
+};
+
+/**************************************************************************
+ * Capability bits for 'fuse_conn_info.capable' and 'fuse_conn_info.want' *
+ **************************************************************************/
+
+/**
+ * Indicates that the filesystem supports asynchronous read requests.
+ *
+ * If this capability is not requested/available, the kernel will
+ * ensure that there is at most one pending read request per
+ * file-handle at any time, and will attempt to order read requests by
+ * increasing offset.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_ASYNC_READ (1 << 0)
+
+/**
+ * Indicates that the filesystem supports "remote" locking.
+ *
+ * This feature is enabled by default when supported by the kernel,
+ * and if getlk() and setlk() handlers are implemented.
+ */
+#define FUSE_CAP_POSIX_LOCKS (1 << 1)
+
+/**
+ * Indicates that the filesystem supports the O_TRUNC open flag. If
+ * disabled, and an application specifies O_TRUNC, fuse first calls
+ * truncate() and then open() with O_TRUNC filtered out.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_ATOMIC_O_TRUNC (1 << 3)
+
+/**
+ * Indicates that the filesystem supports lookups of "." and "..".
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_EXPORT_SUPPORT (1 << 4)
+
+/**
+ * Indicates that the kernel should not apply the umask to the
+ * file mode on create operations.
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_DONT_MASK (1 << 6)
+
+/**
+ * Indicates that libfuse should try to use splice() when writing to
+ * the fuse device. This may improve performance.
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_SPLICE_WRITE (1 << 7)
+
+/**
+ * Indicates that libfuse should try to move pages instead of copying when
+ * writing to / reading from the fuse device. This may improve performance.
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_SPLICE_MOVE (1 << 8)
+
+/**
+ * Indicates that libfuse should try to use splice() when reading from
+ * the fuse device. This may improve performance.
+ *
+ * This feature is enabled by default when supported by the kernel and
+ * if the filesystem implements a write_buf() handler.
+ */
+#define FUSE_CAP_SPLICE_READ (1 << 9)
+
+/**
+ * If set, the calls to flock(2) will be emulated using POSIX locks and must
+ * then be handled by the filesystem's setlock() handler.
+ *
+ * If not set, flock(2) calls will be handled by the FUSE kernel module
+ * internally (so any access that does not go through the kernel cannot be taken
+ * into account).
+ *
+ * This feature is enabled by default when supported by the kernel and
+ * if the filesystem implements a flock() handler.
+ */
+#define FUSE_CAP_FLOCK_LOCKS (1 << 10)
+
+/**
+ * Indicates that the filesystem supports ioctl's on directories.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_IOCTL_DIR (1 << 11)
+
+/**
+ * Traditionally, while a file is open the FUSE kernel module only
+ * asks the filesystem for an update of the file's attributes when a
+ * client attempts to read beyond EOF. This is unsuitable for
+ * e.g. network filesystems, where the file contents may change
+ * without the kernel knowing about it.
+ *
+ * If this flag is set, FUSE will check the validity of the attributes
+ * on every read. If the attributes are no longer valid (i.e., if the
+ * *attr_timeout* passed to fuse_reply_attr() or set in `struct
+ * fuse_entry_param` has passed), it will first issue a `getattr`
+ * request. If the new mtime differs from the previous value, any
+ * cached file *contents* will be invalidated as well.
+ *
+ * This flag should always be set when available. If all file changes
+ * go through the kernel, *attr_timeout* should be set to a very large
+ * number to avoid unnecessary getattr() calls.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_AUTO_INVAL_DATA (1 << 12)
+
+/**
+ * Indicates that the filesystem supports readdirplus.
+ *
+ * This feature is enabled by default when supported by the kernel and if the
+ * filesystem implements a readdirplus() handler.
+ */
+#define FUSE_CAP_READDIRPLUS (1 << 13)
+
+/**
+ * Indicates that the filesystem supports adaptive readdirplus.
+ *
+ * If FUSE_CAP_READDIRPLUS is not set, this flag has no effect.
+ *
+ * If FUSE_CAP_READDIRPLUS is set and this flag is not set, the kernel
+ * will always issue readdirplus() requests to retrieve directory
+ * contents.
+ *
+ * If FUSE_CAP_READDIRPLUS is set and this flag is set, the kernel
+ * will issue both readdir() and readdirplus() requests, depending on
+ * how much information is expected to be required.
+ *
+ * As of Linux 4.20, the algorithm is as follows: when userspace
+ * starts to read directory entries, issue a READDIRPLUS request to
+ * the filesystem. If any entry attributes have been looked up by the
+ * time userspace requests the next batch of entries continue with
+ * READDIRPLUS, otherwise switch to plain READDIR. This will reasult
+ * in eg plain "ls" triggering READDIRPLUS first then READDIR after
+ * that because it doesn't do lookups. "ls -l" should result in all
+ * READDIRPLUS, except if dentries are already cached.
+ *
+ * This feature is enabled by default when supported by the kernel and
+ * if the filesystem implements both a readdirplus() and a readdir()
+ * handler.
+ */
+#define FUSE_CAP_READDIRPLUS_AUTO (1 << 14)
+
+/**
+ * Indicates that the filesystem supports asynchronous direct I/O submission.
+ *
+ * If this capability is not requested/available, the kernel will ensure that
+ * there is at most one pending read and one pending write request per direct
+ * I/O file-handle at any time.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_ASYNC_DIO (1 << 15)
+
+/**
+ * Indicates that writeback caching should be enabled. This means that
+ * individual write request may be buffered and merged in the kernel
+ * before they are send to the filesystem.
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_WRITEBACK_CACHE (1 << 16)
+
+/**
+ * Indicates support for zero-message opens. If this flag is set in
+ * the `capable` field of the `fuse_conn_info` structure, then the
+ * filesystem may return `ENOSYS` from the open() handler to indicate
+ * success. Further attempts to open files will be handled in the
+ * kernel. (If this flag is not set, returning ENOSYS will be treated
+ * as an error and signaled to the caller).
+ *
+ * Setting (or unsetting) this flag in the `want` field has *no
+ * effect*.
+ */
+#define FUSE_CAP_NO_OPEN_SUPPORT (1 << 17)
+
+/**
+ * Indicates support for parallel directory operations. If this flag
+ * is unset, the FUSE kernel module will ensure that lookup() and
+ * readdir() requests are never issued concurrently for the same
+ * directory.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_PARALLEL_DIROPS (1 << 18)
+
+/**
+ * Indicates support for POSIX ACLs.
+ *
+ * If this feature is enabled, the kernel will cache and have
+ * responsibility for enforcing ACLs. ACL will be stored as xattrs and
+ * passed to userspace, which is responsible for updating the ACLs in
+ * the filesystem, keeping the file mode in sync with the ACL, and
+ * ensuring inheritance of default ACLs when new filesystem nodes are
+ * created. Note that this requires that the file system is able to
+ * parse and interpret the xattr representation of ACLs.
+ *
+ * Enabling this feature implicitly turns on the
+ * ``default_permissions`` mount option (even if it was not passed to
+ * mount(2)).
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_POSIX_ACL (1 << 19)
+
+/**
+ * Indicates that the filesystem is responsible for unsetting
+ * setuid and setgid bits when a file is written, truncated, or
+ * its owner is changed.
+ *
+ * This feature is enabled by default when supported by the kernel.
+ */
+#define FUSE_CAP_HANDLE_KILLPRIV (1 << 20)
+
+/**
+ * Indicates support for zero-message opendirs. If this flag is set in
+ * the `capable` field of the `fuse_conn_info` structure, then the filesystem
+ * may return `ENOSYS` from the opendir() handler to indicate success. Further
+ * opendir and releasedir messages will be handled in the kernel. (If this
+ * flag is not set, returning ENOSYS will be treated as an error and signalled
+ * to the caller.)
+ *
+ * Setting (or unsetting) this flag in the `want` field has *no effect*.
+ */
+#define FUSE_CAP_NO_OPENDIR_SUPPORT (1 << 24)
+
+/**
+ * Ioctl flags
+ *
+ * FUSE_IOCTL_COMPAT: 32bit compat ioctl on 64bit machine
+ * FUSE_IOCTL_UNRESTRICTED: not restricted to well-formed ioctls, retry allowed
+ * FUSE_IOCTL_RETRY: retry with new iovecs
+ * FUSE_IOCTL_DIR: is a directory
+ *
+ * FUSE_IOCTL_MAX_IOV: maximum of in_iovecs + out_iovecs
+ */
+#define FUSE_IOCTL_COMPAT (1 << 0)
+#define FUSE_IOCTL_UNRESTRICTED (1 << 1)
+#define FUSE_IOCTL_RETRY (1 << 2)
+#define FUSE_IOCTL_DIR (1 << 4)
+
+#define FUSE_IOCTL_MAX_IOV 256
+
+/**
+ * Connection information, passed to the ->init() method
+ *
+ * Some of the elements are read-write, these can be changed to
+ * indicate the value requested by the filesystem. The requested
+ * value must usually be smaller than the indicated value.
+ */
+struct fuse_conn_info {
+ /**
+ * Major version of the protocol (read-only)
+ */
+ unsigned proto_major;
+
+ /**
+ * Minor version of the protocol (read-only)
+ */
+ unsigned proto_minor;
+
+ /**
+ * Maximum size of the write buffer
+ */
+ unsigned max_write;
+
+ /**
+ * Maximum size of read requests. A value of zero indicates no
+ * limit. However, even if the filesystem does not specify a
+ * limit, the maximum size of read requests will still be
+ * limited by the kernel.
+ *
+ * NOTE: For the time being, the maximum size of read requests
+ * must be set both here *and* passed to fuse_session_new()
+ * using the ``-o max_read=<n>`` mount option. At some point
+ * in the future, specifying the mount option will no longer
+ * be necessary.
+ */
+ unsigned max_read;
+
+ /**
+ * Maximum readahead
+ */
+ unsigned max_readahead;
+
+ /**
+ * Capability flags that the kernel supports (read-only)
+ */
+ unsigned capable;
+
+ /**
+ * Capability flags that the filesystem wants to enable.
+ *
+ * libfuse attempts to initialize this field with
+ * reasonable default values before calling the init() handler.
+ */
+ unsigned want;
+
+ /**
+ * Maximum number of pending "background" requests. A
+ * background request is any type of request for which the
+ * total number is not limited by other means. As of kernel
+ * 4.8, only two types of requests fall into this category:
+ *
+ * 1. Read-ahead requests
+ * 2. Asynchronous direct I/O requests
+ *
+ * Read-ahead requests are generated (if max_readahead is
+ * non-zero) by the kernel to preemptively fill its caches
+ * when it anticipates that userspace will soon read more
+ * data.
+ *
+ * Asynchronous direct I/O requests are generated if
+ * FUSE_CAP_ASYNC_DIO is enabled and userspace submits a large
+ * direct I/O request. In this case the kernel will internally
+ * split it up into multiple smaller requests and submit them
+ * to the filesystem concurrently.
+ *
+ * Note that the following requests are *not* background
+ * requests: writeback requests (limited by the kernel's
+ * flusher algorithm), regular (i.e., synchronous and
+ * buffered) userspace read/write requests (limited to one per
+ * thread), asynchronous read requests (Linux's io_submit(2)
+ * call actually blocks, so these are also limited to one per
+ * thread).
+ */
+ unsigned max_background;
+
+ /**
+ * Kernel congestion threshold parameter. If the number of pending
+ * background requests exceeds this number, the FUSE kernel module will
+ * mark the filesystem as "congested". This instructs the kernel to
+ * expect that queued requests will take some time to complete, and to
+ * adjust its algorithms accordingly (e.g. by putting a waiting thread
+ * to sleep instead of using a busy-loop).
+ */
+ unsigned congestion_threshold;
+
+ /**
+ * When FUSE_CAP_WRITEBACK_CACHE is enabled, the kernel is responsible
+ * for updating mtime and ctime when write requests are received. The
+ * updated values are passed to the filesystem with setattr() requests.
+ * However, if the filesystem does not support the full resolution of
+ * the kernel timestamps (nanoseconds), the mtime and ctime values used
+ * by kernel and filesystem will differ (and result in an apparent
+ * change of times after a cache flush).
+ *
+ * To prevent this problem, this variable can be used to inform the
+ * kernel about the timestamp granularity supported by the file-system.
+ * The value should be power of 10. The default is 1, i.e. full
+ * nano-second resolution. Filesystems supporting only second resolution
+ * should set this to 1000000000.
+ */
+ unsigned time_gran;
+
+ /**
+ * For future use.
+ */
+ unsigned reserved[22];
+};
+
+struct fuse_session;
+struct fuse_pollhandle;
+struct fuse_conn_info_opts;
+
+/**
+ * This function parses several command-line options that can be used
+ * to override elements of struct fuse_conn_info. The pointer returned
+ * by this function should be passed to the
+ * fuse_apply_conn_info_opts() method by the file system's init()
+ * handler.
+ *
+ * Before using this function, think twice if you really want these
+ * parameters to be adjustable from the command line. In most cases,
+ * they should be determined by the file system internally.
+ *
+ * The following options are recognized:
+ *
+ * -o max_write=N sets conn->max_write
+ * -o max_readahead=N sets conn->max_readahead
+ * -o max_background=N sets conn->max_background
+ * -o congestion_threshold=N sets conn->congestion_threshold
+ * -o async_read sets FUSE_CAP_ASYNC_READ in conn->want
+ * -o sync_read unsets FUSE_CAP_ASYNC_READ in conn->want
+ * -o atomic_o_trunc sets FUSE_CAP_ATOMIC_O_TRUNC in conn->want
+ * -o no_remote_lock Equivalent to -o no_remote_flock,no_remote_posix_lock
+ * -o no_remote_flock Unsets FUSE_CAP_FLOCK_LOCKS in conn->want
+ * -o no_remote_posix_lock Unsets FUSE_CAP_POSIX_LOCKS in conn->want
+ * -o [no_]splice_write (un-)sets FUSE_CAP_SPLICE_WRITE in conn->want
+ * -o [no_]splice_move (un-)sets FUSE_CAP_SPLICE_MOVE in conn->want
+ * -o [no_]splice_read (un-)sets FUSE_CAP_SPLICE_READ in conn->want
+ * -o [no_]auto_inval_data (un-)sets FUSE_CAP_AUTO_INVAL_DATA in conn->want
+ * -o readdirplus=no unsets FUSE_CAP_READDIRPLUS in conn->want
+ * -o readdirplus=yes sets FUSE_CAP_READDIRPLUS and unsets
+ * FUSE_CAP_READDIRPLUS_AUTO in conn->want
+ * -o readdirplus=auto sets FUSE_CAP_READDIRPLUS and
+ * FUSE_CAP_READDIRPLUS_AUTO in conn->want
+ * -o [no_]async_dio (un-)sets FUSE_CAP_ASYNC_DIO in conn->want
+ * -o [no_]writeback_cache (un-)sets FUSE_CAP_WRITEBACK_CACHE in conn->want
+ * -o time_gran=N sets conn->time_gran
+ *
+ * Known options will be removed from *args*, unknown options will be
+ * passed through unchanged.
+ *
+ * @param args argument vector (input+output)
+ * @return parsed options
+ **/
+struct fuse_conn_info_opts* fuse_parse_conn_info_opts(struct fuse_args *args);
+
+/**
+ * This function applies the (parsed) parameters in *opts* to the
+ * *conn* pointer. It may modify the following fields: wants,
+ * max_write, max_readahead, congestion_threshold, max_background,
+ * time_gran. A field is only set (or unset) if the corresponding
+ * option has been explicitly set.
+ */
+void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
+ struct fuse_conn_info *conn);
+
+/**
+ * Go into the background
+ *
+ * @param foreground if true, stay in the foreground
+ * @return 0 on success, -1 on failure
+ */
+int fuse_daemonize(int foreground);
+
+/**
+ * Get the version of the library
+ *
+ * @return the version
+ */
+int fuse_version(void);
+
+/**
+ * Get the full package version string of the library
+ *
+ * @return the package version
+ */
+const char *fuse_pkgversion(void);
+
+/**
+ * Destroy poll handle
+ *
+ * @param ph the poll handle
+ */
+void fuse_pollhandle_destroy(struct fuse_pollhandle *ph);
+
+/* ----------------------------------------------------------- *
+ * Data buffer *
+ * ----------------------------------------------------------- */
+
+/**
+ * Buffer flags
+ */
+enum fuse_buf_flags {
+ /**
+ * Buffer contains a file descriptor
+ *
+ * If this flag is set, the .fd field is valid, otherwise the
+ * .mem fields is valid.
+ */
+ FUSE_BUF_IS_FD = (1 << 1),
+
+ /**
+ * Seek on the file descriptor
+ *
+ * If this flag is set then the .pos field is valid and is
+ * used to seek to the given offset before performing
+ * operation on file descriptor.
+ */
+ FUSE_BUF_FD_SEEK = (1 << 2),
+
+ /**
+ * Retry operation on file descriptor
+ *
+ * If this flag is set then retry operation on file descriptor
+ * until .size bytes have been copied or an error or EOF is
+ * detected.
+ */
+ FUSE_BUF_FD_RETRY = (1 << 3),
+};
+
+/**
+ * Buffer copy flags
+ */
+enum fuse_buf_copy_flags {
+ /**
+ * Don't use splice(2)
+ *
+ * Always fall back to using read and write instead of
+ * splice(2) to copy data from one file descriptor to another.
+ *
+ * If this flag is not set, then only fall back if splice is
+ * unavailable.
+ */
+ FUSE_BUF_NO_SPLICE = (1 << 1),
+
+ /**
+ * Force splice
+ *
+ * Always use splice(2) to copy data from one file descriptor
+ * to another. If splice is not available, return -EINVAL.
+ */
+ FUSE_BUF_FORCE_SPLICE = (1 << 2),
+
+ /**
+ * Try to move data with splice.
+ *
+ * If splice is used, try to move pages from the source to the
+ * destination instead of copying. See documentation of
+ * SPLICE_F_MOVE in splice(2) man page.
+ */
+ FUSE_BUF_SPLICE_MOVE = (1 << 3),
+
+ /**
+ * Don't block on the pipe when copying data with splice
+ *
+ * Makes the operations on the pipe non-blocking (if the pipe
+ * is full or empty). See SPLICE_F_NONBLOCK in the splice(2)
+ * man page.
+ */
+ FUSE_BUF_SPLICE_NONBLOCK= (1 << 4),
+};
+
+/**
+ * Single data buffer
+ *
+ * Generic data buffer for I/O, extended attributes, etc... Data may
+ * be supplied as a memory pointer or as a file descriptor
+ */
+struct fuse_buf {
+ /**
+ * Size of data in bytes
+ */
+ size_t size;
+
+ /**
+ * Buffer flags
+ */
+ enum fuse_buf_flags flags;
+
+ /**
+ * Memory pointer
+ *
+ * Used unless FUSE_BUF_IS_FD flag is set.
+ */
+ void *mem;
+
+ /**
+ * File descriptor
+ *
+ * Used if FUSE_BUF_IS_FD flag is set.
+ */
+ int fd;
+
+ /**
+ * File position
+ *
+ * Used if FUSE_BUF_FD_SEEK flag is set.
+ */
+ off_t pos;
+};
+
+/**
+ * Data buffer vector
+ *
+ * An array of data buffers, each containing a memory pointer or a
+ * file descriptor.
+ *
+ * Allocate dynamically to add more than one buffer.
+ */
+struct fuse_bufvec {
+ /**
+ * Number of buffers in the array
+ */
+ size_t count;
+
+ /**
+ * Index of current buffer within the array
+ */
+ size_t idx;
+
+ /**
+ * Current offset within the current buffer
+ */
+ size_t off;
+
+ /**
+ * Array of buffers
+ */
+ struct fuse_buf buf[1];
+};
+
+/* Initialize bufvec with a single buffer of given size */
+#define FUSE_BUFVEC_INIT(size__) \
+ ((struct fuse_bufvec) { \
+ /* .count= */ 1, \
+ /* .idx = */ 0, \
+ /* .off = */ 0, \
+ /* .buf = */ { /* [0] = */ { \
+ /* .size = */ (size__), \
+ /* .flags = */ (enum fuse_buf_flags) 0, \
+ /* .mem = */ NULL, \
+ /* .fd = */ -1, \
+ /* .pos = */ 0, \
+ } } \
+ } )
+
+/**
+ * Get total size of data in a fuse buffer vector
+ *
+ * @param bufv buffer vector
+ * @return size of data
+ */
+size_t fuse_buf_size(const struct fuse_bufvec *bufv);
+
+/**
+ * Copy data from one buffer vector to another
+ *
+ * @param dst destination buffer vector
+ * @param src source buffer vector
+ * @param flags flags controlling the copy
+ * @return actual number of bytes copied or -errno on error
+ */
+ssize_t fuse_buf_copy(struct fuse_bufvec *dst, struct fuse_bufvec *src,
+ enum fuse_buf_copy_flags flags);
+
+/* ----------------------------------------------------------- *
+ * Signal handling *
+ * ----------------------------------------------------------- */
+
+/**
+ * Exit session on HUP, TERM and INT signals and ignore PIPE signal
+ *
+ * Stores session in a global variable. May only be called once per
+ * process until fuse_remove_signal_handlers() is called.
+ *
+ * Once either of the POSIX signals arrives, the signal handler calls
+ * fuse_session_exit().
+ *
+ * @param se the session to exit
+ * @return 0 on success, -1 on failure
+ *
+ * See also:
+ * fuse_remove_signal_handlers()
+ */
+int fuse_set_signal_handlers(struct fuse_session *se);
+
+/**
+ * Restore default signal handlers
+ *
+ * Resets global session. After this fuse_set_signal_handlers() may
+ * be called again.
+ *
+ * @param se the same session as given in fuse_set_signal_handlers()
+ *
+ * See also:
+ * fuse_set_signal_handlers()
+ */
+void fuse_remove_signal_handlers(struct fuse_session *se);
+
+/* ----------------------------------------------------------- *
+ * Compatibility stuff *
+ * ----------------------------------------------------------- */
+
+#if !defined(FUSE_USE_VERSION) || FUSE_USE_VERSION < 30
+# error only API version 30 or greater is supported
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+
+/*
+ * This interface uses 64 bit off_t.
+ *
+ * On 32bit systems please add -D_FILE_OFFSET_BITS=64 to your compile flags!
+ */
+
+#if defined(__GNUC__) && (__GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__ >= 6) && !defined __cplusplus
+_Static_assert(sizeof(off_t) == 8, "fuse: off_t must be 64bit");
+#else
+struct _fuse_off_t_must_be_64bit_dummy_struct \
+ { unsigned _fuse_off_t_must_be_64bit:((sizeof(off_t) == 8) ? 1 : -1); };
+#endif
+
+#endif /* FUSE_COMMON_H_ */
diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
new file mode 100644
index 0000000..d38b630
--- /dev/null
+++ b/tools/virtiofsd/fuse_i.h
@@ -0,0 +1,139 @@
+/*
+ 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
+*/
+
+#include "fuse.h"
+#include "fuse_lowlevel.h"
+
+struct mount_opts;
+
+struct fuse_req {
+ struct fuse_session *se;
+ uint64_t unique;
+ int ctr;
+ pthread_mutex_t lock;
+ struct fuse_ctx ctx;
+ struct fuse_chan *ch;
+ int interrupted;
+ unsigned int ioctl_64bit : 1;
+ union {
+ struct {
+ uint64_t unique;
+ } i;
+ struct {
+ fuse_interrupt_func_t func;
+ void *data;
+ } ni;
+ } u;
+ struct fuse_req *next;
+ struct fuse_req *prev;
+};
+
+struct fuse_notify_req {
+ uint64_t unique;
+ void (*reply)(struct fuse_notify_req *, fuse_req_t, fuse_ino_t,
+ const void *, const struct fuse_buf *);
+ struct fuse_notify_req *next;
+ struct fuse_notify_req *prev;
+};
+
+struct fuse_session {
+ char *mountpoint;
+ volatile int exited;
+ int fd;
+ struct mount_opts *mo;
+ int debug;
+ int deny_others;
+ struct fuse_lowlevel_ops op;
+ int got_init;
+ struct cuse_data *cuse_data;
+ void *userdata;
+ uid_t owner;
+ struct fuse_conn_info conn;
+ struct fuse_req list;
+ struct fuse_req interrupts;
+ pthread_mutex_t lock;
+ int got_destroy;
+ pthread_key_t pipe_key;
+ int broken_splice_nonblock;
+ uint64_t notify_ctr;
+ struct fuse_notify_req notify_list;
+ size_t bufsize;
+ int error;
+};
+
+struct fuse_chan {
+ pthread_mutex_t lock;
+ int ctr;
+ int fd;
+};
+
+/**
+ * Filesystem module
+ *
+ * Filesystem modules are registered with the FUSE_REGISTER_MODULE()
+ * macro.
+ *
+ */
+struct fuse_module {
+ char *name;
+ fuse_module_factory_t factory;
+ struct fuse_module *next;
+ struct fusemod_so *so;
+ int ctr;
+};
+
+/* ----------------------------------------------------------- *
+ * Channel interface (when using -o clone_fd) *
+ * ----------------------------------------------------------- */
+
+/**
+ * Obtain counted reference to the channel
+ *
+ * @param ch the channel
+ * @return the channel
+ */
+struct fuse_chan *fuse_chan_get(struct fuse_chan *ch);
+
+/**
+ * Drop counted reference to a channel
+ *
+ * @param ch the channel
+ */
+void fuse_chan_put(struct fuse_chan *ch);
+
+struct mount_opts *parse_mount_opts(struct fuse_args *args);
+void destroy_mount_opts(struct mount_opts *mo);
+void fuse_mount_version(void);
+unsigned get_max_read(struct mount_opts *o);
+void fuse_kern_unmount(const char *mountpoint, int fd);
+int fuse_kern_mount(const char *mountpoint, struct mount_opts *mo);
+
+int fuse_send_reply_iov_nofree(fuse_req_t req, int error, struct iovec *iov,
+ int count);
+void fuse_free_req(fuse_req_t req);
+
+void cuse_lowlevel_init(fuse_req_t req, fuse_ino_t nodeide, const void *inarg);
+
+int fuse_start_thread(pthread_t *thread_id, void *(*func)(void *), void *arg);
+
+int fuse_session_receive_buf_int(struct fuse_session *se, struct fuse_buf *buf,
+ struct fuse_chan *ch);
+void fuse_session_process_buf_int(struct fuse_session *se,
+ const struct fuse_buf *buf, struct fuse_chan *ch);
+
+struct fuse *fuse_new_31(struct fuse_args *args, const struct fuse_operations *op,
+ size_t op_size, void *private_data);
+int fuse_loop_mt_32(struct fuse *f, struct fuse_loop_config *config);
+int fuse_session_loop_mt_32(struct fuse_session *se, struct fuse_loop_config *config);
+
+#define FUSE_MAX_MAX_PAGES 256
+#define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
+
+/* room needed in buffer to accommodate header */
+#define FUSE_BUFFER_HEADER_SIZE 0x1000
+
diff --git a/tools/virtiofsd/fuse_log.h b/tools/virtiofsd/fuse_log.h
new file mode 100644
index 0000000..5e112e0
--- /dev/null
+++ b/tools/virtiofsd/fuse_log.h
@@ -0,0 +1,82 @@
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2019 Red Hat, Inc.
+
+ This program can be distributed under the terms of the GNU LGPLv2.
+ See the file COPYING.LIB.
+*/
+
+#ifndef FUSE_LOG_H_
+#define FUSE_LOG_H_
+
+/** @file
+ *
+ * This file defines the logging interface of FUSE
+ */
+
+#include <stdarg.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Log severity level
+ *
+ * These levels correspond to syslog(2) log levels since they are widely used.
+ */
+enum fuse_log_level {
+ FUSE_LOG_EMERG,
+ FUSE_LOG_ALERT,
+ FUSE_LOG_CRIT,
+ FUSE_LOG_ERR,
+ FUSE_LOG_WARNING,
+ FUSE_LOG_NOTICE,
+ FUSE_LOG_INFO,
+ FUSE_LOG_DEBUG
+};
+
+/**
+ * Log message handler function.
+ *
+ * This function must be thread-safe. It may be called from any libfuse
+ * function, including fuse_parse_cmdline() and other functions invoked before
+ * a FUSE filesystem is created.
+ *
+ * Install a custom log message handler function using fuse_set_log_func().
+ *
+ * @param level log severity level
+ * @param fmt sprintf-style format string including newline
+ * @param ap format string arguments
+ */
+typedef void (*fuse_log_func_t)(enum fuse_log_level level,
+ const char *fmt, va_list ap);
+
+/**
+ * Install a custom log handler function.
+ *
+ * Log messages are emitted by libfuse functions to report errors and debug
+ * information. Messages are printed to stderr by default but this can be
+ * overridden by installing a custom log message handler function.
+ *
+ * The log message handler function is global and affects all FUSE filesystems
+ * created within this process.
+ *
+ * @param func a custom log message handler function or NULL to revert to
+ * the default
+ */
+void fuse_set_log_func(fuse_log_func_t func);
+
+/**
+ * Emit a log message
+ *
+ * @param level severity level (FUSE_LOG_ERR, FUSE_LOG_DEBUG, etc)
+ * @param fmt sprintf-style format string including newline
+ */
+void fuse_log(enum fuse_log_level level, const char *fmt, ...);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* FUSE_LOG_H_ */
diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h
new file mode 100644
index 0000000..18c6363
--- /dev/null
+++ b/tools/virtiofsd/fuse_lowlevel.h
@@ -0,0 +1,2089 @@
+/*
+ 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
+ *
+ * IMPORTANT: you should define FUSE_USE_VERSION before including this
+ * header. To use the newest API define it to 31 (recommended for any
+ * new application).
+ */
+
+#ifndef FUSE_USE_VERSION
+#error FUSE_USE_VERSION not defined
+#endif
+
+#include "fuse_common.h"
+
+#include <utime.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#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 uint64_t 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;
+
+/** 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.
+ *
+ * If the file system will be exported over NFS, the
+ * ino/generation pairs need to be unique over the file
+ * system's lifetime (rather than just the mount time). So if
+ * the file system reuses an inode after it has been deleted,
+ * it must assign a new, previously unused generation number
+ * to the inode at the same time.
+ *
+ */
+ uint64_t 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 inode attributes. If
+ attributes only change as a result of requests that come
+ through the kernel, this should be set to a very large
+ value. */
+ double attr_timeout;
+
+ /** Validity timeout (in seconds) for the name. If directory
+ entries are changed/deleted only as a result of requests
+ that come through the kernel, this should be set to a very
+ large value. */
+ double entry_timeout;
+};
+
+/**
+ * Additional context associated with requests.
+ *
+ * Note that the reported client uid, gid and pid may be zero in some
+ * situations. For example, if the FUSE file system is running in a
+ * PID or user namespace but then accessed from outside the namespace,
+ * there is no valid uid/pid/gid that could be reported.
+ */
+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;
+
+ /** Umask of the calling process */
+ mode_t umask;
+};
+
+struct fuse_forget_data {
+ fuse_ino_t ino;
+ uint64_t nlookup;
+};
+
+/* '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)
+#define FUSE_SET_ATTR_CTIME (1 << 10)
+
+/* ----------------------------------------------------------- *
+ * 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.
+ *
+ * In general, all methods are expected to perform any necessary
+ * permission checking. However, a filesystem may delegate this task
+ * to the kernel by passing the `default_permissions` mount option to
+ * `fuse_session_new()`. In this case, methods will only be called if
+ * the kernel's permission check has succeeded.
+ *
+ * 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
+ *
+ * This function is called when libfuse establishes
+ * communication with the FUSE kernel module. The file system
+ * should use this module to inspect and/or modify the
+ * connection parameters provided in the `conn` structure.
+ *
+ * Note that some parameters may be overwritten by options
+ * passed to fuse_session_new() which take precedence over the
+ * values set in this handler.
+ *
+ * There's no reply to this function
+ *
+ * @param userdata the user data passed to fuse_session_new()
+ */
+ void (*init) (void *userdata, struct fuse_conn_info *conn);
+
+ /**
+ * Clean up filesystem.
+ *
+ * Called on filesystem exit. When this method is called, the
+ * connection to the kernel may be gone already, so that eg. calls
+ * to fuse_lowlevel_notify_* will fail.
+ *
+ * There's no reply to this function
+ *
+ * @param userdata the user data passed to fuse_session_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
+ *
+ * This function is called when the kernel removes an inode
+ * from its internal caches.
+ *
+ * The inode's lookup count increases by one for every call to
+ * fuse_reply_entry and fuse_reply_create. The nlookup parameter
+ * indicates by how much the lookup count should be decreased.
+ *
+ * Inodes with a non-zero lookup count may receive request from
+ * the kernel even after calls to unlink, rmdir or (when
+ * overwriting an existing file) rename. Filesystems must handle
+ * such requests properly and it is recommended to defer removal
+ * of the inode until the lookup count reaches zero. Calls to
+ * unlink, rmdir or rename will be followed closely by forget
+ * unless the file or directory is open, in which case the
+ * kernel issues forget only after the release or releasedir
+ * calls.
+ *
+ * Note that if a file system will be exported over NFS the
+ * inodes lifetime must extend even beyond forget. See the
+ * generation field in struct fuse_entry_param above.
+ *
+ * On unmount the lookup count for all inodes implicitly drops
+ * to zero. It is not guaranteed that the file system will
+ * receive corresponding forget messages for the affected
+ * inodes.
+ *
+ * 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, uint64_t nlookup);
+
+ /**
+ * Get file attributes.
+ *
+ * If writeback caching is enabled, the kernel may have a
+ * better idea of a file's length than the FUSE file system
+ * (eg if there has been a write that extended the file size,
+ * but that has not yet been passed to the filesystem.n
+ *
+ * In this case, the st_size value provided by the file system
+ * will be ignored.
+ *
+ * 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.
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits if the file
+ * size or owner is being changed.
+ *
+ * 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
+ */
+ 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
+ *
+ * If the file's inode's lookup count is non-zero, the file
+ * system is expected to postpone any removal of the inode
+ * until the lookup count reaches zero (see description of the
+ * forget function).
+ *
+ * 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
+ *
+ * If the directory's inode's lookup count is non-zero, the
+ * file system is expected to postpone any removal of the
+ * inode until the lookup count reaches zero (see description
+ * of the forget function).
+ *
+ * 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
+ *
+ * If the target exists it should be atomically replaced. If
+ * the target's inode's lookup count is non-zero, the file
+ * system is expected to postpone any removal of the inode
+ * until the lookup count reaches zero (see description of the
+ * forget function).
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EINVAL, i.e. all
+ * future bmap requests will fail with EINVAL without being
+ * send to the filesystem process.
+ *
+ * *flags* may be `RENAME_EXCHANGE` or `RENAME_NOREPLACE`. If
+ * RENAME_NOREPLACE is specified, the filesystem must not
+ * overwrite *newname* if it exists and return an error
+ * instead. If `RENAME_EXCHANGE` is specified, the filesystem
+ * must atomically exchange the two files, i.e. both must
+ * exist and neither may be deleted.
+ *
+ * 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,
+ unsigned int flags);
+
+ /**
+ * 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 are available in fi->flags. The following rules
+ * apply.
+ *
+ * - Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be
+ * filtered out / handled by the kernel.
+ *
+ * - Access modes (O_RDONLY, O_WRONLY, O_RDWR) should be used
+ * by the filesystem to check if the operation is
+ * permitted. If the ``-o default_permissions`` mount
+ * option is given, this check is already done by the
+ * kernel before calling open() and may thus be omitted by
+ * the filesystem.
+ *
+ * - When writeback caching is enabled, the kernel may send
+ * read requests even for files opened with O_WRONLY. The
+ * filesystem should be prepared to handle this.
+ *
+ * - When writeback caching is disabled, the filesystem is
+ * expected to properly handle the O_APPEND flag and ensure
+ * that each write is appending to the end of the file.
+ *
+ * - When writeback caching is enabled, the kernel will
+ * handle O_APPEND. However, unless all changes to the file
+ * come through the kernel this will not work reliably. The
+ * filesystem should thus either ignore the O_APPEND flag
+ * (and let the kernel handle it), or return an error
+ * (indicating that reliably O_APPEND is not available).
+ *
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS
+ * and FUSE_CAP_NO_OPEN_SUPPORT is set in
+ * `fuse_conn_info.capable`, this is treated as success and
+ * future calls to open and release will also succeed without being
+ * sent to the filesystem process.
+ *
+ * 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_iov
+ * fuse_reply_data
+ * 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.
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits.
+ *
+ * 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 during close. However, such use is non-portable
+ * because POSIX does not require [close] to wait for delayed I/O to
+ * complete.
+ *
+ * If the filesystem supports file locking operations (setlk,
+ * getlk) it should remove all locks belonging to 'fi->owner'.
+ *
+ * If this request is answered with an error code of ENOSYS,
+ * this is treated as success and future calls to flush() will
+ * succeed automatically without being send to the filesystem
+ * process.
+ *
+ * Valid replies:
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param fi file information
+ *
+ * [close]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/close.html
+ */
+ 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 (unless
+ * the filesystem is force-unmounted).
+ *
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS,
+ * this is treated as success and future calls to fsync() will
+ * succeed automatically without being send to the filesystem
+ * process.
+ *
+ * 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).
+ *
+ * If this request is answered with an error code of ENOSYS and
+ * FUSE_CAP_NO_OPENDIR_SUPPORT is set in `fuse_conn_info.capable`,
+ * this is treated as success and future calls to opendir and
+ * releasedir will also succeed without being sent to the filesystem
+ * process. In addition, the kernel will cache readdir results
+ * as if opendir returned FOPEN_KEEP_CACHE | FOPEN_CACHE_DIR.
+ *
+ * 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.
+ *
+ * Returning a directory entry from readdir() does not affect
+ * its lookup count.
+ *
+ * If off_t is non-zero, then it will correspond to one of the off_t
+ * values that was previously returned by readdir() for the same
+ * directory handle. In this case, readdir() should skip over entries
+ * coming before the position defined by the off_t value. If entries
+ * are added or removed while the directory handle is open, they filesystem
+ * may still include the entries that have been removed, and may not
+ * report the entries that have been created. However, addition or
+ * removal of entries must never cause readdir() to skip over unrelated
+ * entries or to report them more than once. This means
+ * that off_t can not be a simple index that enumerates the entries
+ * that have been returned but must contain sufficient information to
+ * uniquely determine the next directory entry to return even when the
+ * set of entries is changing.
+ *
+ * The function does not have to report the '.' and '..'
+ * entries, but is allowed to do so. Note that, if readdir does
+ * not return '.' or '..', they will not be implicitly returned,
+ * and this behavior is observable by the caller.
+ *
+ * Valid replies:
+ * fuse_reply_buf
+ * fuse_reply_data
+ * 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 (unless the filesystem is force-unmounted).
+ *
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS,
+ * this is treated as success and future calls to fsyncdir() will
+ * succeed automatically without being send to the filesystem
+ * process.
+ *
+ * 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
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EOPNOTSUPP, i.e. all
+ * future setxattr() requests will fail with EOPNOTSUPP without being
+ * send to the filesystem process.
+ *
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EOPNOTSUPP, i.e. all
+ * future getxattr() requests will fail with EOPNOTSUPP without being
+ * send to the filesystem process.
+ *
+ * Valid replies:
+ * fuse_reply_buf
+ * fuse_reply_data
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EOPNOTSUPP, i.e. all
+ * future listxattr() requests will fail with EOPNOTSUPP without being
+ * send to the filesystem process.
+ *
+ * Valid replies:
+ * fuse_reply_buf
+ * fuse_reply_data
+ * 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
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EOPNOTSUPP, i.e. all
+ * future removexattr() requests will fail with EOPNOTSUPP without being
+ * send to the filesystem process.
+ *
+ * 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() and chdir() system
+ * calls. 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
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent success, i.e. this and all future access()
+ * requests will succeed without being send to the filesystem process.
+ *
+ * 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.
+ *
+ * See the description of the open handler for more
+ * information.
+ *
+ * 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.
+ *
+ * If this request is answered with an error code of ENOSYS, the handler
+ * is treated as not implemented (i.e., for this and future requests the
+ * mknod() and open() handlers will be called instead).
+ *
+ * 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
+ *
+ * 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.
+ *
+ * Valid replies:
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param fi file information
+ * @param lock the region/type to set
+ * @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
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure, i.e. all future bmap() requests will
+ * fail with the same error code without being send to the filesystem
+ * process.
+ *
+ * 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);
+
+ /**
+ * Ioctl
+ *
+ * Note: For unrestricted ioctls (not allowed for FUSE
+ * servers), data in and out areas can be discovered by giving
+ * iovs and setting FUSE_IOCTL_RETRY in *flags*. For
+ * restricted ioctls, kernel prepares in/out data area
+ * according to the information encoded in cmd.
+ *
+ * Valid replies:
+ * fuse_reply_ioctl_retry
+ * fuse_reply_ioctl
+ * fuse_reply_ioctl_iov
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param cmd ioctl command
+ * @param arg ioctl argument
+ * @param fi file information
+ * @param flags for FUSE_IOCTL_* flags
+ * @param in_buf data fetched from the caller
+ * @param in_bufsz number of fetched bytes
+ * @param out_bufsz maximum size of output data
+ *
+ * Note : the unsigned long request submitted by the application
+ * is truncated to 32 bits.
+ */
+ void (*ioctl) (fuse_req_t req, fuse_ino_t ino, unsigned int cmd,
+ void *arg, struct fuse_file_info *fi, unsigned flags,
+ const void *in_buf, size_t in_bufsz, size_t out_bufsz);
+
+ /**
+ * Poll for IO readiness
+ *
+ * Note: If ph is non-NULL, the client should notify
+ * when IO readiness events occur by calling
+ * fuse_lowlevel_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.
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as success (with a kernel-defined default poll-mask) and
+ * future calls to pull() will succeed the same way without being send
+ * to the filesystem process.
+ *
+ * Valid replies:
+ * fuse_reply_poll
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param fi file information
+ * @param ph poll handle to be used for notification
+ */
+ void (*poll) (fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi,
+ struct fuse_pollhandle *ph);
+
+ /**
+ * Write data made available in a buffer
+ *
+ * This is a more generic version of the ->write() method. If
+ * FUSE_CAP_SPLICE_READ is set in fuse_conn_info.want and the
+ * kernel supports splicing from the fuse device, then the
+ * data will be made available in pipe for supporting zero
+ * copy data transfer.
+ *
+ * buf->count is guaranteed to be one (and thus buf->idx is
+ * always zero). The write_buf handler must ensure that
+ * bufv->off is correctly updated (reflecting the number of
+ * bytes read from bufv->buf[0]).
+ *
+ * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is
+ * expected to reset the setuid and setgid bits.
+ *
+ * Valid replies:
+ * fuse_reply_write
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param bufv buffer containing the data
+ * @param off offset to write to
+ * @param fi file information
+ */
+ void (*write_buf) (fuse_req_t req, fuse_ino_t ino,
+ struct fuse_bufvec *bufv, off_t off,
+ struct fuse_file_info *fi);
+
+ /**
+ * Callback function for the retrieve request
+ *
+ * Valid replies:
+ * fuse_reply_none
+ *
+ * @param req request handle
+ * @param cookie user data supplied to fuse_lowlevel_notify_retrieve()
+ * @param ino the inode number supplied to fuse_lowlevel_notify_retrieve()
+ * @param offset the offset supplied to fuse_lowlevel_notify_retrieve()
+ * @param bufv the buffer containing the returned data
+ */
+ void (*retrieve_reply) (fuse_req_t req, void *cookie, fuse_ino_t ino,
+ off_t offset, struct fuse_bufvec *bufv);
+
+ /**
+ * Forget about multiple inodes
+ *
+ * See description of the forget function for more
+ * information.
+ *
+ * Valid replies:
+ * fuse_reply_none
+ *
+ * @param req request handle
+ */
+ void (*forget_multi) (fuse_req_t req, size_t count,
+ struct fuse_forget_data *forgets);
+
+ /**
+ * Acquire, modify or release a BSD file lock
+ *
+ * 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.
+ *
+ * Valid replies:
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param fi file information
+ * @param op the locking operation, see flock(2)
+ */
+ void (*flock) (fuse_req_t req, fuse_ino_t ino,
+ struct fuse_file_info *fi, int op);
+
+ /**
+ * Allocate requested space. If this function returns success then
+ * subsequent writes to the specified range shall not fail due to the lack
+ * of free space on the file system storage media.
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EOPNOTSUPP, i.e. all
+ * future fallocate() requests will fail with EOPNOTSUPP without being
+ * send to the filesystem process.
+ *
+ * Valid replies:
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param offset starting point for allocated region
+ * @param length size of allocated region
+ * @param mode determines the operation to be performed on the given range,
+ * see fallocate(2)
+ */
+ void (*fallocate) (fuse_req_t req, fuse_ino_t ino, int mode,
+ off_t offset, off_t length, struct fuse_file_info *fi);
+
+ /**
+ * Read directory with attributes
+ *
+ * Send a buffer filled using fuse_add_direntry_plus(), 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.
+ *
+ * In contrast to readdir() (which does not affect the lookup counts),
+ * the lookup count of every entry returned by readdirplus(), except "."
+ * and "..", is incremented by one.
+ *
+ * Valid replies:
+ * fuse_reply_buf
+ * fuse_reply_data
+ * 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 (*readdirplus) (fuse_req_t req, fuse_ino_t ino, size_t size, off_t off,
+ struct fuse_file_info *fi);
+
+ /**
+ * Copy a range of data from one file to another
+ *
+ * Performs an optimized copy between two file descriptors without the
+ * additional cost of transferring data through the FUSE kernel module
+ * to user space (glibc) and then back into the FUSE filesystem again.
+ *
+ * In case this method is not implemented, glibc falls back to reading
+ * data from the source and writing to the destination. Effectively
+ * doing an inefficient copy of the data.
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure with error code EOPNOTSUPP, i.e. all
+ * future copy_file_range() requests will fail with EOPNOTSUPP without
+ * being send to the filesystem process.
+ *
+ * Valid replies:
+ * fuse_reply_write
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino_in the inode number or the source file
+ * @param off_in starting point from were the data should be read
+ * @param fi_in file information of the source file
+ * @param ino_out the inode number or the destination file
+ * @param off_out starting point where the data should be written
+ * @param fi_out file information of the destination file
+ * @param len maximum size of the data to copy
+ * @param flags passed along with the copy_file_range() syscall
+ */
+ void (*copy_file_range) (fuse_req_t req, fuse_ino_t ino_in,
+ off_t off_in, struct fuse_file_info *fi_in,
+ fuse_ino_t ino_out, off_t off_out,
+ struct fuse_file_info *fi_out, size_t len,
+ int flags);
+
+ /**
+ * Find next data or hole after the specified offset
+ *
+ * If this request is answered with an error code of ENOSYS, this is
+ * treated as a permanent failure, i.e. all future lseek() requests will
+ * fail with the same error code without being send to the filesystem
+ * process.
+ *
+ * Valid replies:
+ * fuse_reply_lseek
+ * fuse_reply_err
+ *
+ * @param req request handle
+ * @param ino the inode number
+ * @param off offset to start search from
+ * @param whence either SEEK_DATA or SEEK_HOLE
+ * @param fi file information
+ */
+ void (*lseek) (fuse_req_t req, fuse_ino_t ino, off_t off, int whence,
+ struct fuse_file_info *fi);
+};
+
+/**
+ * Reply with an error code or success.
+ *
+ * Possible requests:
+ * all except forget
+ *
+ * Whereever possible, error codes should be chosen from the list of
+ * documented error conditions in the corresponding system calls
+ * manpage.
+ *
+ * An error code of ENOSYS is sometimes treated specially. This is
+ * indicated in the documentation of the affected handler functions.
+ *
+ * The following requests may be answered with a zero error code:
+ * unlink, rmdir, rename, flush, release, fsync, fsyncdir, setxattr,
+ * removexattr, setlk.
+ *
+ * @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
+ * forget_multi
+ * retrieve_reply
+ *
+ * @param req request handle
+ */
+void fuse_reply_none(fuse_req_t req);
+
+/**
+ * Reply with a directory entry
+ *
+ * Possible requests:
+ * lookup, mknod, mkdir, symlink, link
+ *
+ * Side effects:
+ * increments the lookup count on success
+ *
+ * @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
+ *
+ * Side effects:
+ * increments the lookup count on success
+ *
+ * @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 attr 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);
+
+/**
+ * Reply with data copied/moved from buffer(s)
+ *
+ * Zero copy data transfer ("splicing") will be used under
+ * the following circumstances:
+ *
+ * 1. FUSE_CAP_SPLICE_WRITE is set in fuse_conn_info.want, and
+ * 2. the kernel supports splicing from the fuse device
+ * (FUSE_CAP_SPLICE_WRITE is set in fuse_conn_info.capable), and
+ * 3. *flags* does not contain FUSE_BUF_NO_SPLICE
+ * 4. The amount of data that is provided in file-descriptor backed
+ * buffers (i.e., buffers for which bufv[n].flags == FUSE_BUF_FD)
+ * is at least twice the page size.
+ *
+ * In order for SPLICE_F_MOVE to be used, the following additional
+ * conditions have to be fulfilled:
+ *
+ * 1. FUSE_CAP_SPLICE_MOVE is set in fuse_conn_info.want, and
+ * 2. the kernel supports it (i.e, FUSE_CAP_SPLICE_MOVE is set in
+ fuse_conn_info.capable), and
+ * 3. *flags* contains FUSE_BUF_SPLICE_MOVE
+ *
+ * Note that, if splice is used, the data is actually spliced twice:
+ * once into a temporary pipe (to prepend header data), and then again
+ * into the kernel. If some of the provided buffers are memory-backed,
+ * the data in them is copied in step one and spliced in step two.
+ *
+ * The FUSE_BUF_SPLICE_FORCE_SPLICE and FUSE_BUF_SPLICE_NONBLOCK flags
+ * are silently ignored.
+ *
+ * Possible requests:
+ * read, readdir, getxattr, listxattr
+ *
+ * Side effects:
+ * when used to return data from a readdirplus() (but not readdir())
+ * call, increments the lookup count of each returned entry by one
+ * on success.
+ *
+ * @param req request handle
+ * @param bufv buffer vector
+ * @param flags flags controlling the copy
+ * @return zero for success, -errno for failure to send reply
+ */
+int fuse_reply_data(fuse_req_t req, struct fuse_bufvec *bufv,
+ enum fuse_buf_copy_flags flags);
+
+/**
+ * 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);
+
+/**
+ * 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
+ */
+int fuse_reply_statfs(fuse_req_t req, const struct statvfs *stbuf);
+
+/**
+ * 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, const 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. If 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.
+ *
+ * *off* should be any non-zero value that the filesystem can use to
+ * identify the current point in the directory stream. It does not
+ * need to be the actual physical position. A value of zero is
+ * reserved to mean "from the beginning", and should therefore never
+ * be used (the first call to fuse_add_direntry should be passed the
+ * offset of the second directory entry).
+ *
+ * @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 name 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);
+
+/**
+ * Add a directory entry to the buffer with the attributes
+ *
+ * See documentation of `fuse_add_direntry()` for more details.
+ *
+ * @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 name the name of the entry
+ * @param e the directory entry
+ * @param off the offset of the next entry
+ * @return the space needed for the entry
+ */
+size_t fuse_add_direntry_plus(fuse_req_t req, char *buf, size_t bufsize,
+ const char *name,
+ const struct fuse_entry_param *e, off_t off);
+
+/**
+ * Reply to ask for data fetch and output buffer preparation. ioctl
+ * will be retried with the specified input data fetched and output
+ * buffer prepared.
+ *
+ * Possible requests:
+ * ioctl
+ *
+ * @param req request handle
+ * @param in_iov iovec specifying data to fetch from the caller
+ * @param in_count number of entries in in_iov
+ * @param out_iov iovec specifying addresses to write output to
+ * @param out_count number of entries in out_iov
+ * @return zero for success, -errno for failure to send reply
+ */
+int fuse_reply_ioctl_retry(fuse_req_t req,
+ const struct iovec *in_iov, size_t in_count,
+ const struct iovec *out_iov, size_t out_count);
+
+/**
+ * Reply to finish ioctl
+ *
+ * Possible requests:
+ * ioctl
+ *
+ * @param req request handle
+ * @param result result to be passed to the caller
+ * @param buf buffer containing output data
+ * @param size length of output data
+ */
+int fuse_reply_ioctl(fuse_req_t req, int result, const void *buf, size_t size);
+
+/**
+ * Reply to finish ioctl with iov buffer
+ *
+ * Possible requests:
+ * ioctl
+ *
+ * @param req request handle
+ * @param result result to be passed to the caller
+ * @param iov the vector containing the data
+ * @param count the size of vector
+ */
+int fuse_reply_ioctl_iov(fuse_req_t req, int result, const struct iovec *iov,
+ int count);
+
+/**
+ * Reply with poll result event mask
+ *
+ * @param req request handle
+ * @param revents poll result event mask
+ */
+int fuse_reply_poll(fuse_req_t req, unsigned revents);
+
+/**
+ * Reply with offset
+ *
+ * Possible requests:
+ * lseek
+ *
+ * @param req request handle
+ * @param off offset of next data or hole
+ * @return zero for success, -errno for failure to send reply
+ */
+int fuse_reply_lseek(fuse_req_t req, off_t off);
+
+/* ----------------------------------------------------------- *
+ * Notification *
+ * ----------------------------------------------------------- */
+
+/**
+ * Notify IO readiness event
+ *
+ * For more information, please read comment for poll operation.
+ *
+ * @param ph poll handle to notify IO readiness event for
+ */
+int fuse_lowlevel_notify_poll(struct fuse_pollhandle *ph);
+
+/**
+ * Notify to invalidate cache for an inode.
+ *
+ * Added in FUSE protocol version 7.12. If the kernel does not support
+ * this (or a newer) version, the function will return -ENOSYS and do
+ * nothing.
+ *
+ * If the filesystem has writeback caching enabled, invalidating an
+ * inode will first trigger a writeback of all dirty pages. The call
+ * will block until all writeback requests have completed and the
+ * inode has been invalidated. It will, however, not wait for
+ * completion of pending writeback requests that have been issued
+ * before.
+ *
+ * If there are no dirty pages, this function will never block.
+ *
+ * @param se the session object
+ * @param ino the inode number
+ * @param off the offset in the inode where to start invalidating
+ * or negative to invalidate attributes only
+ * @param len the amount of cache to invalidate or 0 for all
+ * @return zero for success, -errno for failure
+ */
+int fuse_lowlevel_notify_inval_inode(struct fuse_session *se, fuse_ino_t ino,
+ off_t off, off_t len);
+
+/**
+ * Notify to invalidate parent attributes and the dentry matching
+ * parent/name
+ *
+ * To avoid a deadlock this function must not be called in the
+ * execution path of a related filesytem operation or within any code
+ * that could hold a lock that could be needed to execute such an
+ * operation. As of kernel 4.18, a "related operation" is a lookup(),
+ * symlink(), mknod(), mkdir(), unlink(), rename(), link() or create()
+ * request for the parent, and a setattr(), unlink(), rmdir(),
+ * rename(), setxattr(), removexattr(), readdir() or readdirplus()
+ * request for the inode itself.
+ *
+ * When called correctly, this function will never block.
+ *
+ * Added in FUSE protocol version 7.12. If the kernel does not support
+ * this (or a newer) version, the function will return -ENOSYS and do
+ * nothing.
+ *
+ * @param se the session object
+ * @param parent inode number
+ * @param name file name
+ * @param namelen strlen() of file name
+ * @return zero for success, -errno for failure
+ */
+int fuse_lowlevel_notify_inval_entry(struct fuse_session *se, fuse_ino_t parent,
+ const char *name, size_t namelen);
+
+/**
+ * This function behaves like fuse_lowlevel_notify_inval_entry() with
+ * the following additional effect (at least as of Linux kernel 4.8):
+ *
+ * If the provided *child* inode matches the inode that is currently
+ * associated with the cached dentry, and if there are any inotify
+ * watches registered for the dentry, then the watchers are informed
+ * that the dentry has been deleted.
+ *
+ * To avoid a deadlock this function must not be called while
+ * executing a related filesytem operation or while holding a lock
+ * that could be needed to execute such an operation (see the
+ * description of fuse_lowlevel_notify_inval_entry() for more
+ * details).
+ *
+ * When called correctly, this function will never block.
+ *
+ * Added in FUSE protocol version 7.18. If the kernel does not support
+ * this (or a newer) version, the function will return -ENOSYS and do
+ * nothing.
+ *
+ * @param se the session object
+ * @param parent inode number
+ * @param child inode number
+ * @param name file name
+ * @param namelen strlen() of file name
+ * @return zero for success, -errno for failure
+ */
+int fuse_lowlevel_notify_delete(struct fuse_session *se,
+ fuse_ino_t parent, fuse_ino_t child,
+ const char *name, size_t namelen);
+
+/**
+ * Store data to the kernel buffers
+ *
+ * Synchronously store data in the kernel buffers belonging to the
+ * given inode. The stored data is marked up-to-date (no read will be
+ * performed against it, unless it's invalidated or evicted from the
+ * cache).
+ *
+ * If the stored data overflows the current file size, then the size
+ * is extended, similarly to a write(2) on the filesystem.
+ *
+ * If this function returns an error, then the store wasn't fully
+ * completed, but it may have been partially completed.
+ *
+ * Added in FUSE protocol version 7.15. If the kernel does not support
+ * this (or a newer) version, the function will return -ENOSYS and do
+ * nothing.
+ *
+ * @param se the session object
+ * @param ino the inode number
+ * @param offset the starting offset into the file to store to
+ * @param bufv buffer vector
+ * @param flags flags controlling the copy
+ * @return zero for success, -errno for failure
+ */
+int fuse_lowlevel_notify_store(struct fuse_session *se, fuse_ino_t ino,
+ off_t offset, struct fuse_bufvec *bufv,
+ enum fuse_buf_copy_flags flags);
+/**
+ * Retrieve data from the kernel buffers
+ *
+ * Retrieve data in the kernel buffers belonging to the given inode.
+ * If successful then the retrieve_reply() method will be called with
+ * the returned data.
+ *
+ * Only present pages are returned in the retrieve reply. Retrieving
+ * stops when it finds a non-present page and only data prior to that
+ * is returned.
+ *
+ * If this function returns an error, then the retrieve will not be
+ * completed and no reply will be sent.
+ *
+ * This function doesn't change the dirty state of pages in the kernel
+ * buffer. For dirty pages the write() method will be called
+ * regardless of having been retrieved previously.
+ *
+ * Added in FUSE protocol version 7.15. If the kernel does not support
+ * this (or a newer) version, the function will return -ENOSYS and do
+ * nothing.
+ *
+ * @param se the session object
+ * @param ino the inode number
+ * @param size the number of bytes to retrieve
+ * @param offset the starting offset into the file to retrieve from
+ * @param cookie user data to supply to the reply callback
+ * @return zero for success, -errno for failure
+ */
+int fuse_lowlevel_notify_retrieve(struct fuse_session *se, fuse_ino_t ino,
+ size_t size, off_t offset, void *cookie);
+
+
+/* ----------------------------------------------------------- *
+ * Utility functions *
+ * ----------------------------------------------------------- */
+
+/**
+ * Get the userdata from the request
+ *
+ * @param req request handle
+ * @return the user data passed to fuse_session_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);
+
+/**
+ * Get the current supplementary group IDs for the specified 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 req request handle
+ * @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_req_getgroups(fuse_req_t req, int size, gid_t list[]);
+
+/**
+ * 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
+ * @param 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);
+
+
+/* ----------------------------------------------------------- *
+ * Inquiry functions *
+ * ----------------------------------------------------------- */
+
+/**
+ * Print low-level version information to stdout.
+ */
+void fuse_lowlevel_version(void);
+
+/**
+ * Print available low-level options to stdout. This is not an
+ * exhaustive list, but includes only those options that may be of
+ * interest to an end-user of a file system.
+ */
+void fuse_lowlevel_help(void);
+
+/**
+ * Print available options for `fuse_parse_cmdline()`.
+ */
+void fuse_cmdline_help(void);
+
+/* ----------------------------------------------------------- *
+ * Filesystem setup & teardown *
+ * ----------------------------------------------------------- */
+
+struct fuse_cmdline_opts {
+ int singlethread;
+ int foreground;
+ int debug;
+ int nodefault_subtype;
+ char *mountpoint;
+ int show_version;
+ int show_help;
+ int clone_fd;
+ unsigned int max_idle_threads;
+};
+
+/**
+ * Utility function to parse common options for simple file systems
+ * using the low-level API. A help text that describes the available
+ * options can be printed with `fuse_cmdline_help`. A single
+ * non-option argument is treated as the mountpoint. Multiple
+ * non-option arguments will result in an error.
+ *
+ * If neither -o subtype= or -o fsname= options are given, a new
+ * subtype option will be added and set to the basename of the program
+ * (the fsname will remain unset, and then defaults to "fuse").
+ *
+ * Known options will be removed from *args*, unknown options will
+ * remain.
+ *
+ * @param args argument vector (input+output)
+ * @param opts output argument for parsed options
+ * @return 0 on success, -1 on failure
+ */
+int fuse_parse_cmdline(struct fuse_args *args,
+ struct fuse_cmdline_opts *opts);
+
+/**
+ * Create a low level session.
+ *
+ * Returns a session structure suitable for passing to
+ * fuse_session_mount() and fuse_session_loop().
+ *
+ * This function accepts most file-system independent mount options
+ * (like context, nodev, ro - see mount(8)), as well as the general
+ * fuse mount options listed in mount.fuse(8) (e.g. -o allow_root and
+ * -o default_permissions, but not ``-o use_ino``). Instead of `-o
+ * debug`, debugging may also enabled with `-d` or `--debug`.
+ *
+ * If not all options are known, an error message is written to stderr
+ * and the function returns NULL.
+ *
+ * Option parsing skips argv[0], which is assumed to contain the
+ * program name. To prevent accidentally passing an option in
+ * argv[0], this element must always be present (even if no options
+ * are specified). It may be set to the empty string ('\0') if no
+ * reasonable value can be provided.
+ *
+ * @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 fuse session on success, NULL on failure
+ **/
+struct fuse_session *fuse_session_new(struct fuse_args *args,
+ const struct fuse_lowlevel_ops *op,
+ size_t op_size, void *userdata);
+
+/**
+ * Mount a FUSE file system.
+ *
+ * @param mountpoint the mount point path
+ * @param se session object
+ *
+ * @return 0 on success, -1 on failure.
+ **/
+int fuse_session_mount(struct fuse_session *se, const char *mountpoint);
+
+/**
+ * Enter a single threaded, blocking event loop.
+ *
+ * When the event loop terminates because the connection to the FUSE
+ * kernel module has been closed, this function returns zero. This
+ * happens when the filesystem is unmounted regularly (by the
+ * filesystem owner or root running the umount(8) or fusermount(1)
+ * command), or if connection is explicitly severed by writing ``1``
+ * to the``abort`` file in ``/sys/fs/fuse/connections/NNN``. The only
+ * way to distinguish between these two conditions is to check if the
+ * filesystem is still mounted after the session loop returns.
+ *
+ * When some error occurs during request processing, the function
+ * returns a negated errno(3) value.
+ *
+ * If the loop has been terminated because of a signal handler
+ * installed by fuse_set_signal_handlers(), this function returns the
+ * (positive) signal value that triggered the exit.
+ *
+ * @param se the session
+ * @return 0, -errno, or a signal value
+ */
+int fuse_session_loop(struct fuse_session *se);
+
+/**
+ * Enter a multi-threaded event loop.
+ *
+ * For a description of the return value and the conditions when the
+ * event loop exits, refer to the documentation of
+ * fuse_session_loop().
+ *
+ * @param se the session
+ * @param config session loop configuration
+ * @return see fuse_session_loop()
+ */
+#if FUSE_USE_VERSION < 32
+int fuse_session_loop_mt_31(struct fuse_session *se, int clone_fd);
+#define fuse_session_loop_mt(se, clone_fd) fuse_session_loop_mt_31(se, clone_fd)
+#else
+int fuse_session_loop_mt(struct fuse_session *se, struct fuse_loop_config *config);
+#endif
+
+/**
+ * Flag a session as terminated.
+ *
+ * This function is invoked by the POSIX signal handlers, when
+ * registered using fuse_set_signal_handlers(). It will cause any
+ * running event loops to terminate on the next opportunity.
+ *
+ * @param se the session
+ */
+void fuse_session_exit(struct fuse_session *se);
+
+/**
+ * Reset the terminated flag of a session
+ *
+ * @param se the session
+ */
+void fuse_session_reset(struct fuse_session *se);
+
+/**
+ * Query the terminated flag of a session
+ *
+ * @param se the session
+ * @return 1 if exited, 0 if not exited
+ */
+int fuse_session_exited(struct fuse_session *se);
+
+/**
+ * Ensure that file system is unmounted.
+ *
+ * In regular operation, the file system is typically unmounted by the
+ * user calling umount(8) or fusermount(1), which then terminates the
+ * FUSE session loop. However, the session loop may also terminate as
+ * a result of an explicit call to fuse_session_exit() (e.g. by a
+ * signal handler installed by fuse_set_signal_handler()). In this
+ * case the filesystem remains mounted, but any attempt to access it
+ * will block (while the filesystem process is still running) or give
+ * an ESHUTDOWN error (after the filesystem process has terminated).
+ *
+ * If the communication channel with the FUSE kernel module is still
+ * open (i.e., if the session loop was terminated by an explicit call
+ * to fuse_session_exit()), this function will close it and unmount
+ * the filesystem. If the communication channel has been closed by the
+ * kernel, this method will do (almost) nothing.
+ *
+ * NOTE: The above semantics mean that if the connection to the kernel
+ * is terminated via the ``/sys/fs/fuse/connections/NNN/abort`` file,
+ * this method will *not* unmount the filesystem.
+ *
+ * @param se the session
+ */
+void fuse_session_unmount(struct fuse_session *se);
+
+/**
+ * Destroy a session
+ *
+ * @param se the session
+ */
+void fuse_session_destroy(struct fuse_session *se);
+
+/* ----------------------------------------------------------- *
+ * Custom event loop support *
+ * ----------------------------------------------------------- */
+
+/**
+ * Return file descriptor for communication with kernel.
+ *
+ * The file selector can be used to integrate FUSE with a custom event
+ * loop. Whenever data is available for reading on the provided fd,
+ * the event loop should call `fuse_session_receive_buf` followed by
+ * `fuse_session_process_buf` to process the request.
+ *
+ * The returned file descriptor is valid until `fuse_session_unmount`
+ * is called.
+ *
+ * @param se the session
+ * @return a file descriptor
+ */
+int fuse_session_fd(struct fuse_session *se);
+
+/**
+ * Process a raw request supplied in a generic buffer
+ *
+ * The fuse_buf may contain a memory buffer or a pipe file descriptor.
+ *
+ * @param se the session
+ * @param buf the fuse_buf containing the request
+ */
+void fuse_session_process_buf(struct fuse_session *se,
+ const struct fuse_buf *buf);
+
+/**
+ * Read a raw request from the kernel into the supplied buffer.
+ *
+ * Depending on file system options, system capabilities, and request
+ * size the request is either read into a memory buffer or spliced
+ * into a temporary pipe.
+ *
+ * @param se the session
+ * @param buf the fuse_buf to store the request in
+ * @return the actual size of the raw request, or -errno on error
+ */
+int fuse_session_receive_buf(struct fuse_session *se, struct fuse_buf *buf);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* FUSE_LOWLEVEL_H_ */
diff --git a/tools/virtiofsd/fuse_misc.h b/tools/virtiofsd/fuse_misc.h
new file mode 100644
index 0000000..2f6663e
--- /dev/null
+++ b/tools/virtiofsd/fuse_misc.h
@@ -0,0 +1,59 @@
+/*
+ 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
+*/
+
+#include <pthread.h>
+
+/*
+ Versioned symbols cannot be used in some cases because it
+ - confuse the dynamic linker in uClibc
+ - not supported on MacOSX (in MachO binary format)
+*/
+#if (!defined(__UCLIBC__) && !defined(__APPLE__))
+#define FUSE_SYMVER(x) __asm__(x)
+#else
+#define FUSE_SYMVER(x)
+#endif
+
+#ifndef USE_UCLIBC
+#define fuse_mutex_init(mut) pthread_mutex_init(mut, NULL)
+#else
+/* Is this hack still needed? */
+static inline void fuse_mutex_init(pthread_mutex_t *mut)
+{
+ pthread_mutexattr_t attr;
+ pthread_mutexattr_init(&attr);
+ pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
+ pthread_mutex_init(mut, &attr);
+ pthread_mutexattr_destroy(&attr);
+}
+#endif
+
+#ifdef HAVE_STRUCT_STAT_ST_ATIM
+/* Linux */
+#define ST_ATIM_NSEC(stbuf) ((stbuf)->st_atim.tv_nsec)
+#define ST_CTIM_NSEC(stbuf) ((stbuf)->st_ctim.tv_nsec)
+#define ST_MTIM_NSEC(stbuf) ((stbuf)->st_mtim.tv_nsec)
+#define ST_ATIM_NSEC_SET(stbuf, val) (stbuf)->st_atim.tv_nsec = (val)
+#define ST_CTIM_NSEC_SET(stbuf, val) (stbuf)->st_ctim.tv_nsec = (val)
+#define ST_MTIM_NSEC_SET(stbuf, val) (stbuf)->st_mtim.tv_nsec = (val)
+#elif defined(HAVE_STRUCT_STAT_ST_ATIMESPEC)
+/* FreeBSD */
+#define ST_ATIM_NSEC(stbuf) ((stbuf)->st_atimespec.tv_nsec)
+#define ST_CTIM_NSEC(stbuf) ((stbuf)->st_ctimespec.tv_nsec)
+#define ST_MTIM_NSEC(stbuf) ((stbuf)->st_mtimespec.tv_nsec)
+#define ST_ATIM_NSEC_SET(stbuf, val) (stbuf)->st_atimespec.tv_nsec = (val)
+#define ST_CTIM_NSEC_SET(stbuf, val) (stbuf)->st_ctimespec.tv_nsec = (val)
+#define ST_MTIM_NSEC_SET(stbuf, val) (stbuf)->st_mtimespec.tv_nsec = (val)
+#else
+#define ST_ATIM_NSEC(stbuf) 0
+#define ST_CTIM_NSEC(stbuf) 0
+#define ST_MTIM_NSEC(stbuf) 0
+#define ST_ATIM_NSEC_SET(stbuf, val) do { } while (0)
+#define ST_CTIM_NSEC_SET(stbuf, val) do { } while (0)
+#define ST_MTIM_NSEC_SET(stbuf, val) do { } while (0)
+#endif
diff --git a/tools/virtiofsd/fuse_opt.h b/tools/virtiofsd/fuse_opt.h
new file mode 100644
index 0000000..d8573e7
--- /dev/null
+++ b/tools/virtiofsd/fuse_opt.h
@@ -0,0 +1,271 @@
+/*
+ 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_OPT_H_
+#define FUSE_OPT_H_
+
+/** @file
+ *
+ * This file defines the option parsing interface of FUSE
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Option description
+ *
+ * This structure describes a single option, and action associated
+ * with it, in case it matches.
+ *
+ * More than one such match may occur, in which case the action for
+ * each match is executed.
+ *
+ * There are three possible actions in case of a match:
+ *
+ * i) An integer (int or unsigned) variable determined by 'offset' is
+ * set to 'value'
+ *
+ * ii) The processing function is called, with 'value' as the key
+ *
+ * iii) An integer (any) or string (char *) variable determined by
+ * 'offset' is set to the value of an option parameter
+ *
+ * 'offset' should normally be either set to
+ *
+ * - 'offsetof(struct foo, member)' actions i) and iii)
+ *
+ * - -1 action ii)
+ *
+ * The 'offsetof()' macro is defined in the <stddef.h> header.
+ *
+ * The template determines which options match, and also have an
+ * effect on the action. Normally the action is either i) or ii), but
+ * if a format is present in the template, then action iii) is
+ * performed.
+ *
+ * The types of templates are:
+ *
+ * 1) "-x", "-foo", "--foo", "--foo-bar", etc. These match only
+ * themselves. Invalid values are "--" and anything beginning
+ * with "-o"
+ *
+ * 2) "foo", "foo-bar", etc. These match "-ofoo", "-ofoo-bar" or
+ * the relevant option in a comma separated option list
+ *
+ * 3) "bar=", "--foo=", etc. These are variations of 1) and 2)
+ * which have a parameter
+ *
+ * 4) "bar=%s", "--foo=%lu", etc. Same matching as above but perform
+ * action iii).
+ *
+ * 5) "-x ", etc. Matches either "-xparam" or "-x param" as
+ * two separate arguments
+ *
+ * 6) "-x %s", etc. Combination of 4) and 5)
+ *
+ * If the format is "%s", memory is allocated for the string unlike with
+ * scanf(). The previous value (if non-NULL) stored at the this location is
+ * freed.
+ */
+struct fuse_opt {
+ /** Matching template and optional parameter formatting */
+ const char *templ;
+
+ /**
+ * Offset of variable within 'data' parameter of fuse_opt_parse()
+ * or -1
+ */
+ unsigned long offset;
+
+ /**
+ * Value to set the variable to, or to be passed as 'key' to the
+ * processing function. Ignored if template has a format
+ */
+ int value;
+};
+
+/**
+ * Key option. In case of a match, the processing function will be
+ * called with the specified key.
+ */
+#define FUSE_OPT_KEY(templ, key) { templ, -1U, key }
+
+/**
+ * Last option. An array of 'struct fuse_opt' must end with a NULL
+ * template value
+ */
+#define FUSE_OPT_END { NULL, 0, 0 }
+
+/**
+ * Argument list
+ */
+struct fuse_args {
+ /** Argument count */
+ int argc;
+
+ /** Argument vector. NULL terminated */
+ char **argv;
+
+ /** Is 'argv' allocated? */
+ int allocated;
+};
+
+/**
+ * Initializer for 'struct fuse_args'
+ */
+#define FUSE_ARGS_INIT(argc, argv) { argc, argv, 0 }
+
+/**
+ * Key value passed to the processing function if an option did not
+ * match any template
+ */
+#define FUSE_OPT_KEY_OPT -1
+
+/**
+ * Key value passed to the processing function for all non-options
+ *
+ * Non-options are the arguments beginning with a character other than
+ * '-' or all arguments after the special '--' option
+ */
+#define FUSE_OPT_KEY_NONOPT -2
+
+/**
+ * Special key value for options to keep
+ *
+ * Argument is not passed to processing function, but behave as if the
+ * processing function returned 1
+ */
+#define FUSE_OPT_KEY_KEEP -3
+
+/**
+ * Special key value for options to discard
+ *
+ * Argument is not passed to processing function, but behave as if the
+ * processing function returned zero
+ */
+#define FUSE_OPT_KEY_DISCARD -4
+
+/**
+ * Processing function
+ *
+ * This function is called if
+ * - option did not match any 'struct fuse_opt'
+ * - argument is a non-option
+ * - option did match and offset was set to -1
+ *
+ * The 'arg' parameter will always contain the whole argument or
+ * option including the parameter if exists. A two-argument option
+ * ("-x foo") is always converted to single argument option of the
+ * form "-xfoo" before this function is called.
+ *
+ * Options of the form '-ofoo' are passed to this function without the
+ * '-o' prefix.
+ *
+ * The return value of this function determines whether this argument
+ * is to be inserted into the output argument vector, or discarded.
+ *
+ * @param data is the user data passed to the fuse_opt_parse() function
+ * @param arg is the whole argument or option
+ * @param key determines why the processing function was called
+ * @param outargs the current output argument list
+ * @return -1 on error, 0 if arg is to be discarded, 1 if arg should be kept
+ */
+typedef int (*fuse_opt_proc_t)(void *data, const char *arg, int key,
+ struct fuse_args *outargs);
+
+/**
+ * Option parsing function
+ *
+ * If 'args' was returned from a previous call to fuse_opt_parse() or
+ * it was constructed from
+ *
+ * A NULL 'args' is equivalent to an empty argument vector
+ *
+ * A NULL 'opts' is equivalent to an 'opts' array containing a single
+ * end marker
+ *
+ * A NULL 'proc' is equivalent to a processing function always
+ * returning '1'
+ *
+ * @param args is the input and output argument list
+ * @param data is the user data
+ * @param opts is the option description array
+ * @param proc is the processing function
+ * @return -1 on error, 0 on success
+ */
+int fuse_opt_parse(struct fuse_args *args, void *data,
+ const struct fuse_opt opts[], fuse_opt_proc_t proc);
+
+/**
+ * Add an option to a comma separated option list
+ *
+ * @param opts is a pointer to an option list, may point to a NULL value
+ * @param opt is the option to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_add_opt(char **opts, const char *opt);
+
+/**
+ * Add an option, escaping commas, to a comma separated option list
+ *
+ * @param opts is a pointer to an option list, may point to a NULL value
+ * @param opt is the option to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_add_opt_escaped(char **opts, const char *opt);
+
+/**
+ * Add an argument to a NULL terminated argument vector
+ *
+ * @param args is the structure containing the current argument list
+ * @param arg is the new argument to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_add_arg(struct fuse_args *args, const char *arg);
+
+/**
+ * Add an argument at the specified position in a NULL terminated
+ * argument vector
+ *
+ * Adds the argument to the N-th position. This is useful for adding
+ * options at the beginning of the array which must not come after the
+ * special '--' option.
+ *
+ * @param args is the structure containing the current argument list
+ * @param pos is the position at which to add the argument
+ * @param arg is the new argument to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_insert_arg(struct fuse_args *args, int pos, const char *arg);
+
+/**
+ * Free the contents of argument list
+ *
+ * The structure itself is not freed
+ *
+ * @param args is the structure containing the argument list
+ */
+void fuse_opt_free_args(struct fuse_args *args);
+
+
+/**
+ * Check if an option matches
+ *
+ * @param opts is the option description array
+ * @param opt is the option to match
+ * @return 1 if a match is found, 0 if not
+ */
+int fuse_opt_match(const struct fuse_opt opts[], const char *opt);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* FUSE_OPT_H_ */
diff --git a/tools/virtiofsd/passthrough_helpers.h b/tools/virtiofsd/passthrough_helpers.h
new file mode 100644
index 0000000..6b77c33
--- /dev/null
+++ b/tools/virtiofsd/passthrough_helpers.h
@@ -0,0 +1,76 @@
+/*
+ * FUSE: Filesystem in Userspace
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE
+ */
+
+/*
+ * Creates files on the underlying file system in response to a FUSE_MKNOD
+ * operation
+ */
+static int mknod_wrapper(int dirfd, const char *path, const char *link,
+ int mode, dev_t rdev)
+{
+ int res;
+
+ if (S_ISREG(mode)) {
+ res = openat(dirfd, path, O_CREAT | O_EXCL | O_WRONLY, mode);
+ if (res >= 0)
+ res = close(res);
+ } else if (S_ISDIR(mode)) {
+ res = mkdirat(dirfd, path, mode);
+ } else if (S_ISLNK(mode) && link != NULL) {
+ res = symlinkat(link, dirfd, path);
+ } else if (S_ISFIFO(mode)) {
+ res = mkfifoat(dirfd, path, mode);
+#ifdef __FreeBSD__
+ } else if (S_ISSOCK(mode)) {
+ struct sockaddr_un su;
+ int fd;
+
+ if (strlen(path) >= sizeof(su.sun_path)) {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+ fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (fd >= 0) {
+ /*
+ * We must bind the socket to the underlying file
+ * system to create the socket file, even though
+ * we'll never listen on this socket.
+ */
+ su.sun_family = AF_UNIX;
+ strncpy(su.sun_path, path, sizeof(su.sun_path));
+ res = bindat(dirfd, fd, (struct sockaddr*)&su,
+ sizeof(su));
+ if (res == 0)
+ close(fd);
+ } else {
+ res = -1;
+ }
+#endif
+ } else {
+ res = mknodat(dirfd, path, mode, rdev);
+ }
+
+ return res;
+}
--
1.8.3.1
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