devices: fs: Add fuse constants and struct definitions

Add the constants and struct definitions from the kernel fuse interface.
These bindings are manually generated from `include/uapi/linux/fuse.h`
in the kernel repo.

BUG=b:136128319
TEST=none;  these aren't used anywhere yet

Change-Id: I03d11bc55eca6b8269f1e63a1187ef458ee16f28
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1705655
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Stephen Barber <smbarber@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Chirantan Ekbote <chirantan@chromium.org>

3 files changed, 1056 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index b20bee3..074bca4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -57,6 +57,11 @@ dependencies = [
 ]
 
 [[package]]
+name = "bitflags"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "cc"
 version = "1.0.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -138,6 +143,7 @@ version = "0.1.0"
 dependencies = [
  "audio_streams 0.1.0",
  "bit_field 0.1.0",
+ "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "data_model 0.1.0",
  "disk 0.1.0",
  "enumn 0.1.0",
@@ -601,6 +607,7 @@ dependencies = [
 ]
 
 [metadata]
+"checksum bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3d155346769a6855b86399e9bc3814ab343cd3d62c7e985113d46a0ec3c281fd"
 "checksum cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "f159dfd43363c4d08055a07703eb7a3406b0dac4d0584d96965a3262db3c9d16"
 "checksum cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0c4e7bb64a8ebb0d856483e1e682ea3422f883c5f5615a90d51a2c82fe87fdd3"
 "checksum getopts 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)" = "0a7292d30132fb5424b354f5dc02512a86e4c516fe544bb7a25e7f266951b797"
diff --git a/devices/Cargo.toml b/devices/Cargo.toml
index 2ddfcd0..ab240c3 100644
--- a/devices/Cargo.toml
+++ b/devices/Cargo.toml
@@ -14,6 +14,7 @@ x = ["gpu_display/x"]
 [dependencies]
 audio_streams = "*"
 bit_field = { path = "../bit_field" }
+bitflags = "1"
 data_model = { path = "../data_model" }
 disk = { path = "../disk" }
 enumn = { path = "../enumn" }
diff --git a/devices/src/virtio/fs/fuse.rs b/devices/src/virtio/fs/fuse.rs
new file mode 100644
index 0000000..0fac6e6
--- /dev/null
+++ b/devices/src/virtio/fs/fuse.rs
@@ -0,0 +1,1048 @@
+// Copyright 2019 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+use std::mem;
+
+use bitflags::bitflags;
+use data_model::DataInit;
+use enumn::N;
+use libc;
+
+/// Version number of this interface.
+pub const KERNEL_VERSION: u32 = 7;
+
+/// Minor version number of this interface.
+pub const KERNEL_MINOR_VERSION: u32 = 27;
+
+/// The ID of the inode corresponding to the root directory of the file system.
+pub const ROOT_ID: u64 = 1;
+
+// Bitmasks for `fuse_setattr_in.valid`.
+const FATTR_MODE: u32 = 1;
+const FATTR_UID: u32 = 2;
+const FATTR_GID: u32 = 4;
+const FATTR_SIZE: u32 = 8;
+const FATTR_ATIME: u32 = 16;
+const FATTR_MTIME: u32 = 32;
+pub const FATTR_FH: u32 = 64;
+const FATTR_ATIME_NOW: u32 = 128;
+const FATTR_MTIME_NOW: u32 = 256;
+pub const FATTR_LOCKOWNER: u32 = 512;
+const FATTR_CTIME: u32 = 1024;
+
+bitflags! {
+    pub struct SetattrValid: u32 {
+        const MODE = FATTR_MODE;
+        const UID = FATTR_UID;
+        const GID = FATTR_GID;
+        const SIZE = FATTR_SIZE;
+        const ATIME = FATTR_ATIME;
+        const MTIME = FATTR_MTIME;
+        const ATIME_NOW = FATTR_ATIME_NOW;
+        const MTIME_NOW = FATTR_MTIME_NOW;
+        const CTIME = FATTR_CTIME;
+    }
+}
+
+// Flags returned by the OPEN request.
+
+/// Bypass page cache for this open file.
+const FOPEN_DIRECT_IO: u32 = 1;
+
+/// Don't invalidate the data cache on open.
+const FOPEN_KEEP_CACHE: u32 = 2;
+
+/// The file is not seekable.
+const FOPEN_NONSEEKABLE: u32 = 4;
+
+bitflags! {
+    /// Options controlling the behavior of files opened by the server in response
+    /// to an open or create request.
+    pub struct OpenOptions: u32 {
+        const DIRECT_IO = FOPEN_DIRECT_IO;
+        const KEEP_CACHE = FOPEN_KEEP_CACHE;
+        const NONSEEKABLE = FOPEN_NONSEEKABLE;
+    }
+}
+
+// INIT request/reply flags.
+
+/// Asynchronous read requests.
+const ASYNC_READ: u32 = 1;
+
+/// Remote locking for POSIX file locks.
+const POSIX_LOCKS: u32 = 2;
+
+/// Kernel sends file handle for fstat, etc... (not yet supported).
+const FILE_OPS: u32 = 4;
+
+/// Handles the O_TRUNC open flag in the filesystem.
+const ATOMIC_O_TRUNC: u32 = 8;
+
+/// FileSystem handles lookups of "." and "..".
+const EXPORT_SUPPORT: u32 = 16;
+
+/// FileSystem can handle write size larger than 4kB.
+const BIG_WRITES: u32 = 32;
+
+/// Don't apply umask to file mode on create operations.
+const DONT_MASK: u32 = 64;
+
+/// Kernel supports splice write on the device.
+const SPLICE_WRITE: u32 = 128;
+
+/// Kernel supports splice move on the device.
+const SPLICE_MOVE: u32 = 256;
+
+/// Kernel supports splice read on the device.
+const SPLICE_READ: u32 = 512;
+
+/// Remote locking for BSD style file locks.
+const FLOCK_LOCKS: u32 = 1024;
+
+/// Kernel supports ioctl on directories.
+const HAS_IOCTL_DIR: u32 = 2048;
+
+/// Automatically invalidate cached pages.
+const AUTO_INVAL_DATA: u32 = 4096;
+
+/// Do READDIRPLUS (READDIR+LOOKUP in one).
+const DO_READDIRPLUS: u32 = 8192;
+
+/// Adaptive readdirplus.
+const READDIRPLUS_AUTO: u32 = 16384;
+
+/// Asynchronous direct I/O submission.
+const ASYNC_DIO: u32 = 32768;
+
+/// Use writeback cache for buffered writes.
+const WRITEBACK_CACHE: u32 = 65536;
+
+/// Kernel supports zero-message opens.
+const NO_OPEN_SUPPORT: u32 = 131072;
+
+/// Allow parallel lookups and readdir.
+const PARALLEL_DIROPS: u32 = 262144;
+
+/// Fs handles killing suid/sgid/cap on write/chown/trunc.
+const HANDLE_KILLPRIV: u32 = 524288;
+
+/// FileSystem supports posix acls.
+const POSIX_ACL: u32 = 1048576;
+
+bitflags! {
+    /// A bitfield passed in as a parameter to and returned from the `init` method of the
+    /// `FileSystem` trait.
+    pub struct FsOptions: u32 {
+        /// 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.
+        const ASYNC_READ = ASYNC_READ;
+
+        /// Indicates that the filesystem supports "remote" locking.
+        ///
+        /// This feature is not enabled by default and should only be set if the filesystem
+        /// implements the `getlk` and `setlk` methods of the `FileSystem` trait.
+        const POSIX_LOCKS = POSIX_LOCKS;
+
+        /// Kernel sends file handle for fstat, etc... (not yet supported).
+        const FILE_OPS = FILE_OPS;
+
+        /// Indicates that the filesystem supports the `O_TRUNC` open flag. If disabled, and an
+        /// application specifies `O_TRUNC`, fuse first calls `setattr` to truncate the file and
+        /// then calls `open` with `O_TRUNC` filtered out.
+        ///
+        /// This feature is enabled by default when supported by the kernel.
+        const ATOMIC_O_TRUNC = ATOMIC_O_TRUNC;
+
+        /// Indicates that the filesystem supports lookups of "." and "..".
+        ///
+        /// This feature is disabled by default.
+        const EXPORT_SUPPORT = EXPORT_SUPPORT;
+
+        /// FileSystem can handle write size larger than 4kB.
+        const BIG_WRITES = BIG_WRITES;
+
+        /// Indicates that the kernel should not apply the umask to the file mode on create
+        /// operations.
+        ///
+        /// This feature is disabled by default.
+        const DONT_MASK = DONT_MASK;
+
+        /// Indicates that the server should try to use `splice(2)` when writing to the fuse device.
+        /// This may improve performance.
+        ///
+        /// This feature is not currently supported.
+        const SPLICE_WRITE = SPLICE_WRITE;
+
+        /// Indicates that the server should try to move pages instead of copying when writing to /
+        /// reading from the fuse device. This may improve performance.
+        ///
+        /// This feature is not currently supported.
+        const SPLICE_MOVE = SPLICE_MOVE;
+
+        /// Indicates that the server should try to use `splice(2)` when reading from the fuse
+        /// device. This may improve performance.
+        ///
+        /// This feature is not currently supported.
+        const SPLICE_READ = SPLICE_READ;
+
+        /// If set, then calls to `flock` will be emulated using POSIX locks and must
+        /// then be handled by the filesystem's `setlock()` handler.
+        ///
+        /// If not set, `flock` 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 disabled by default.
+        const FLOCK_LOCKS = FLOCK_LOCKS;
+
+        /// Indicates that the filesystem supports ioctl's on directories.
+        ///
+        /// This feature is enabled by default when supported by the kernel.
+        const HAS_IOCTL_DIR = HAS_IOCTL_DIR;
+
+        /// 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 *attribute* timeout has expired) then
+        /// FUSE will first send another `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, *attribute* validity should be set to a very large number to avoid unnecessary
+        /// `getattr()` calls.
+        ///
+        /// This feature is enabled by default when supported by the kernel.
+        const AUTO_INVAL_DATA = AUTO_INVAL_DATA;
+
+        /// Indicates that the filesystem supports readdirplus.
+        ///
+        /// The feature is not enabled by default and should only be set if the filesystem
+        /// implements the `readdirplus` method of the `FileSystem` trait.
+        const DO_READDIRPLUS = DO_READDIRPLUS;
+
+        /// Indicates that the filesystem supports adaptive readdirplus.
+        ///
+        /// If `DO_READDIRPLUS` is not set, this flag has no effect.
+        ///
+        /// If `DO_READDIRPLUS` is set and this flag is not set, the kernel will always issue
+        /// `readdirplus()` requests to retrieve directory contents.
+        ///
+        /// If `DO_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.
+        ///
+        /// This feature is not enabled by default and should only be set if the file system
+        /// implements both the `readdir` and `readdirplus` methods of the `FileSystem` trait.
+        const READDIRPLUS_AUTO = READDIRPLUS_AUTO;
+
+        /// 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.
+        const ASYNC_DIO = ASYNC_DIO;
+
+        /// Indicates that writeback caching should be enabled. This means that individual write
+        /// request may be buffered and merged in the kernel before they are sent to the file
+        /// system.
+        ///
+        /// This feature is disabled by default.
+        const WRITEBACK_CACHE = WRITEBACK_CACHE;
+
+        /// Indicates support for zero-message opens. If this flag is set in the `capable` parameter
+        /// of the `init` trait method, then the file system 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 not setting) the field in the `FsOptions` returned from the `init` method
+        /// has no effect.
+        const ZERO_MESSAGE_OPEN = NO_OPEN_SUPPORT;
+
+        /// 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.
+        const PARALLEL_DIROPS = PARALLEL_DIROPS;
+
+        /// Indicates that the file system 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.
+        const HANDLE_KILLPRIV = HANDLE_KILLPRIV;
+
+        /// 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.
+        const POSIX_ACL = POSIX_ACL;
+    }
+}
+
+// Release flags.
+pub const RELEASE_FLUSH: u32 = 1;
+pub const RELEASE_FLOCK_UNLOCK: u32 = 2;
+
+// Getattr flags.
+pub const GETATTR_FH: u32 = 1;
+
+// Lock flags.
+pub const LK_FLOCK: u32 = 1;
+
+// Write flags.
+
+/// Delayed write from page cache, file handle is guessed.
+pub const WRITE_CACHE: u32 = 1;
+
+/// `lock_owner` field is valid.
+pub const WRITE_LOCKOWNER: u32 = 2;
+
+// Read flags.
+pub const READ_LOCKOWNER: u32 = 2;
+
+// Ioctl flags.
+
+/// 32bit compat ioctl on 64bit machine
+const IOCTL_COMPAT: u32 = 1;
+
+/// Not restricted to well-formed ioctls, retry allowed
+const IOCTL_UNRESTRICTED: u32 = 2;
+
+/// Retry with new iovecs
+const IOCTL_RETRY: u32 = 4;
+
+/// 32bit ioctl
+const IOCTL_32BIT: u32 = 8;
+
+/// Is a directory
+const IOCTL_DIR: u32 = 16;
+
+/// Maximum of in_iovecs + out_iovecs
+const IOCTL_MAX_IOV: u32 = 256;
+
+bitflags! {
+    pub struct IoctlFlags: u32 {
+        /// 32bit compat ioctl on 64bit machine
+        const IOCTL_COMPAT = IOCTL_COMPAT;
+
+        /// Not restricted to well-formed ioctls, retry allowed
+        const IOCTL_UNRESTRICTED = IOCTL_UNRESTRICTED;
+
+        /// Retry with new iovecs
+        const IOCTL_RETRY = IOCTL_RETRY;
+
+        /// 32bit ioctl
+        const IOCTL_32BIT = IOCTL_32BIT;
+
+        /// Is a directory
+        const IOCTL_DIR = IOCTL_DIR;
+
+        /// Maximum of in_iovecs + out_iovecs
+        const IOCTL_MAX_IOV = IOCTL_MAX_IOV;
+    }
+}
+
+/// Request poll notify.
+pub const POLL_SCHEDULE_NOTIFY: u32 = 1;
+
+/// The read buffer is required to be at least 8k, but may be much larger.
+pub const FUSE_MIN_READ_BUFFER: u32 = 8192;
+
+pub const FUSE_COMPAT_ENTRY_OUT_SIZE: u32 = 120;
+pub const FUSE_COMPAT_ATTR_OUT_SIZE: u32 = 96;
+pub const FUSE_COMPAT_MKNOD_IN_SIZE: u32 = 8;
+pub const FUSE_COMPAT_WRITE_IN_SIZE: u32 = 24;
+pub const FUSE_COMPAT_STATFS_SIZE: u32 = 48;
+pub const FUSE_COMPAT_INIT_OUT_SIZE: u32 = 8;
+pub const FUSE_COMPAT_22_INIT_OUT_SIZE: u32 = 24;
+
+// Message definitions follow.  It is safe to implement DataInit for all of these
+// because they are POD types.
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Attr {
+    pub ino: u64,
+    pub size: u64,
+    pub blocks: u64,
+    pub atime: u64,
+    pub mtime: u64,
+    pub ctime: u64,
+    pub atimensec: u32,
+    pub mtimensec: u32,
+    pub ctimensec: u32,
+    pub mode: u32,
+    pub nlink: u32,
+    pub uid: u32,
+    pub gid: u32,
+    pub rdev: u32,
+    pub blksize: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for Attr {}
+
+impl From<libc::stat64> for Attr {
+    fn from(st: libc::stat64) -> Attr {
+        Attr {
+            ino: st.st_ino,
+            size: st.st_size as u64,
+            blocks: st.st_blocks as u64,
+            atime: st.st_atime as u64,
+            mtime: st.st_mtime as u64,
+            ctime: st.st_ctime as u64,
+            atimensec: st.st_atime_nsec as u32,
+            mtimensec: st.st_mtime_nsec as u32,
+            ctimensec: st.st_ctime_nsec as u32,
+            mode: st.st_mode,
+            nlink: st.st_nlink as u32,
+            uid: st.st_uid,
+            gid: st.st_gid,
+            rdev: st.st_rdev as u32,
+            blksize: st.st_blksize as u32,
+            ..Default::default()
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Kstatfs {
+    pub blocks: u64,
+    pub bfree: u64,
+    pub bavail: u64,
+    pub files: u64,
+    pub ffree: u64,
+    pub bsize: u32,
+    pub namelen: u32,
+    pub frsize: u32,
+    pub padding: u32,
+    pub spare: [u32; 6],
+}
+unsafe impl DataInit for Kstatfs {}
+
+impl From<libc::statvfs64> for Kstatfs {
+    fn from(st: libc::statvfs64) -> Self {
+        Kstatfs {
+            blocks: st.f_blocks,
+            bfree: st.f_bfree,
+            bavail: st.f_bavail,
+            files: st.f_files,
+            ffree: st.f_ffree,
+            bsize: st.f_bsize as u32,
+            namelen: st.f_namemax as u32,
+            frsize: st.f_frsize as u32,
+            ..Default::default()
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct FileLock {
+    pub start: u64,
+    pub end: u64,
+    pub type_: u32,
+    pub pid: u32, /* tgid */
+}
+unsafe impl DataInit for FileLock {}
+
+#[repr(u32)]
+#[derive(Debug, Copy, Clone, N)]
+pub enum Opcode {
+    Lookup = 1,
+    Forget = 2, /* No Reply */
+    Getattr = 3,
+    Setattr = 4,
+    Readlink = 5,
+    Symlink = 6,
+    Mknod = 8,
+    Mkdir = 9,
+    Unlink = 10,
+    Rmdir = 11,
+    Rename = 12,
+    Link = 13,
+    Open = 14,
+    Read = 15,
+    Write = 16,
+    Statfs = 17,
+    Release = 18,
+    Fsync = 20,
+    Setxattr = 21,
+    Getxattr = 22,
+    Listxattr = 23,
+    Removexattr = 24,
+    Flush = 25,
+    Init = 26,
+    Opendir = 27,
+    Readdir = 28,
+    Releasedir = 29,
+    Fsyncdir = 30,
+    Getlk = 31,
+    Setlk = 32,
+    Setlkw = 33,
+    Access = 34,
+    Create = 35,
+    Interrupt = 36,
+    Bmap = 37,
+    Destroy = 38,
+    Ioctl = 39,
+    Poll = 40,
+    NotifyReply = 41,
+    BatchForget = 42,
+    Fallocate = 43,
+    Readdirplus = 44,
+    Rename2 = 45,
+    Lseek = 46,
+}
+
+#[repr(u32)]
+#[derive(Debug, Copy, Clone, N)]
+pub enum NotifyOpcode {
+    Poll = 1,
+    InvalInode = 2,
+    InvalEntry = 3,
+    Store = 4,
+    Retrieve = 5,
+    Delete = 6,
+    CodeMax = 7,
+}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct EntryOut {
+    pub nodeid: u64,      /* Inode ID */
+    pub generation: u64,  /* Inode generation: nodeid:gen must be unique for the fs's lifetime */
+    pub entry_valid: u64, /* Cache timeout for the name */
+    pub attr_valid: u64,  /* Cache timeout for the attributes */
+    pub entry_valid_nsec: u32,
+    pub attr_valid_nsec: u32,
+    pub attr: Attr,
+}
+unsafe impl DataInit for EntryOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct ForgetIn {
+    pub nlookup: u64,
+}
+unsafe impl DataInit for ForgetIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct ForgetOne {
+    pub nodeid: u64,
+    pub nlookup: u64,
+}
+unsafe impl DataInit for ForgetOne {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct BatchForgetIn {
+    pub count: u32,
+    pub dummy: u32,
+}
+unsafe impl DataInit for BatchForgetIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct GetattrIn {
+    pub flags: u32,
+    pub dummy: u32,
+    pub fh: u64,
+}
+unsafe impl DataInit for GetattrIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct AttrOut {
+    pub attr_valid: u64, /* Cache timeout for the attributes */
+    pub attr_valid_nsec: u32,
+    pub dummy: u32,
+    pub attr: Attr,
+}
+unsafe impl DataInit for AttrOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct MknodIn {
+    pub mode: u32,
+    pub rdev: u32,
+    pub umask: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for MknodIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct MkdirIn {
+    pub mode: u32,
+    pub umask: u32,
+}
+unsafe impl DataInit for MkdirIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct RenameIn {
+    pub newdir: u64,
+}
+unsafe impl DataInit for RenameIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Rename2In {
+    pub newdir: u64,
+    pub flags: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for Rename2In {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct LinkIn {
+    pub oldnodeid: u64,
+}
+unsafe impl DataInit for LinkIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct SetattrIn {
+    pub valid: u32,
+    pub padding: u32,
+    pub fh: u64,
+    pub size: u64,
+    pub lock_owner: u64,
+    pub atime: u64,
+    pub mtime: u64,
+    pub ctime: u64,
+    pub atimensec: u32,
+    pub mtimensec: u32,
+    pub ctimensec: u32,
+    pub mode: u32,
+    pub unused4: u32,
+    pub uid: u32,
+    pub gid: u32,
+    pub unused5: u32,
+}
+unsafe impl DataInit for SetattrIn {}
+
+impl Into<libc::stat64> for SetattrIn {
+    fn into(self) -> libc::stat64 {
+        // Safe because we are zero-initializing a struct with only POD fields.
+        let mut out: libc::stat64 = unsafe { mem::zeroed() };
+        out.st_mode = self.mode;
+        out.st_uid = self.uid;
+        out.st_gid = self.gid;
+        out.st_size = self.size as i64;
+        out.st_atime = self.atime as i64;
+        out.st_mtime = self.mtime as i64;
+        out.st_ctime = self.ctime as i64;
+        out.st_atime_nsec = self.atimensec as i64;
+        out.st_mtime_nsec = self.mtimensec as i64;
+        out.st_ctime_nsec = self.ctimensec as i64;
+
+        out
+    }
+}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct OpenIn {
+    pub flags: u32,
+    pub unused: u32,
+}
+unsafe impl DataInit for OpenIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct CreateIn {
+    pub flags: u32,
+    pub mode: u32,
+    pub umask: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for CreateIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct OpenOut {
+    pub fh: u64,
+    pub open_flags: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for OpenOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct ReleaseIn {
+    pub fh: u64,
+    pub flags: u32,
+    pub release_flags: u32,
+    pub lock_owner: u64,
+}
+unsafe impl DataInit for ReleaseIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct FlushIn {
+    pub fh: u64,
+    pub unused: u32,
+    pub padding: u32,
+    pub lock_owner: u64,
+}
+unsafe impl DataInit for FlushIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct ReadIn {
+    pub fh: u64,
+    pub offset: u64,
+    pub size: u32,
+    pub read_flags: u32,
+    pub lock_owner: u64,
+    pub flags: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for ReadIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct WriteIn {
+    pub fh: u64,
+    pub offset: u64,
+    pub size: u32,
+    pub write_flags: u32,
+    pub lock_owner: u64,
+    pub flags: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for WriteIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct WriteOut {
+    pub size: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for WriteOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct StatfsOut {
+    pub st: Kstatfs,
+}
+unsafe impl DataInit for StatfsOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct FsyncIn {
+    pub fh: u64,
+    pub fsync_flags: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for FsyncIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct SetxattrIn {
+    pub size: u32,
+    pub flags: u32,
+}
+unsafe impl DataInit for SetxattrIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct GetxattrIn {
+    pub size: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for GetxattrIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct GetxattrOut {
+    pub size: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for GetxattrOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct LkIn {
+    pub fh: u64,
+    pub owner: u64,
+    pub lk: FileLock,
+    pub lk_flags: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for LkIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct LkOut {
+    pub lk: FileLock,
+}
+unsafe impl DataInit for LkOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct AccessIn {
+    pub mask: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for AccessIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct InitIn {
+    pub major: u32,
+    pub minor: u32,
+    pub max_readahead: u32,
+    pub flags: u32,
+}
+unsafe impl DataInit for InitIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct InitOut {
+    pub major: u32,
+    pub minor: u32,
+    pub max_readahead: u32,
+    pub flags: u32,
+    pub max_background: u16,
+    pub congestion_threshold: u16,
+    pub max_write: u32,
+    pub time_gran: u32,
+    pub unused: [u32; 9],
+}
+unsafe impl DataInit for InitOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct InterruptIn {
+    pub unique: u64,
+}
+unsafe impl DataInit for InterruptIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct BmapIn {
+    pub block: u64,
+    pub blocksize: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for BmapIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct BmapOut {
+    pub block: u64,
+}
+unsafe impl DataInit for BmapOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct IoctlIn {
+    pub fh: u64,
+    pub flags: u32,
+    pub cmd: u32,
+    pub arg: u64,
+    pub in_size: u32,
+    pub out_size: u32,
+}
+unsafe impl DataInit for IoctlIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct IoctlIovec {
+    pub base: u64,
+    pub len: u64,
+}
+unsafe impl DataInit for IoctlIovec {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct IoctlOut {
+    pub result: i32,
+    pub flags: u32,
+    pub in_iovs: u32,
+    pub out_iovs: u32,
+}
+unsafe impl DataInit for IoctlOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct PollIn {
+    pub fh: u64,
+    pub kh: u64,
+    pub flags: u32,
+    pub events: u32,
+}
+unsafe impl DataInit for PollIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct PollOut {
+    pub revents: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for PollOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct NotifyPollWakeupOut {
+    pub kh: u64,
+}
+unsafe impl DataInit for NotifyPollWakeupOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct FallocateIn {
+    pub fh: u64,
+    pub offset: u64,
+    pub length: u64,
+    pub mode: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for FallocateIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct InHeader {
+    pub len: u32,
+    pub opcode: u32,
+    pub unique: u64,
+    pub nodeid: u64,
+    pub uid: u32,
+    pub gid: u32,
+    pub pid: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for InHeader {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct OutHeader {
+    pub len: u32,
+    pub error: i32,
+    pub unique: u64,
+}
+unsafe impl DataInit for OutHeader {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Dirent {
+    pub ino: u64,
+    pub off: u64,
+    pub namelen: u32,
+    pub type_: u32,
+    // char name[];
+}
+unsafe impl DataInit for Dirent {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Direntplus {
+    pub entry_out: EntryOut,
+    pub dirent: Dirent,
+}
+unsafe impl DataInit for Direntplus {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct NotifyInvalInodeOut {
+    pub ino: u64,
+    pub off: i64,
+    pub len: i64,
+}
+unsafe impl DataInit for NotifyInvalInodeOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct NotifyInvalEntryOut {
+    pub parent: u64,
+    pub namelen: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for NotifyInvalEntryOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct NotifyDeleteOut {
+    pub parent: u64,
+    pub child: u64,
+    pub namelen: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for NotifyDeleteOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct NotifyStoreOut {
+    pub nodeid: u64,
+    pub offset: u64,
+    pub size: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for NotifyStoreOut {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Notify_Retrieve_Out {
+    pub notify_unique: u64,
+    pub nodeid: u64,
+    pub offset: u64,
+    pub size: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for Notify_Retrieve_Out {}
+
+/* Matches the size of fuse_write_in */
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct NotifyRetrieveIn {
+    pub dummy1: u64,
+    pub offset: u64,
+    pub size: u32,
+    pub dummy2: u32,
+    pub dummy3: u64,
+    pub dummy4: u64,
+}
+unsafe impl DataInit for NotifyRetrieveIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct LseekIn {
+    pub fh: u64,
+    pub offset: u64,
+    pub whence: u32,
+    pub padding: u32,
+}
+unsafe impl DataInit for LseekIn {}
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct LseekOut {
+    pub offset: u64,
+}
+unsafe impl DataInit for LseekOut {}