virtiofsd: Pull in upstream headers

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>

1 files changed, 823 insertions, 0 deletions

diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h
new file mode 100644
index 0000000000..2d686b2ac4
--- /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_ */