Add ioctl example

This matches libfuse's example:

https://github.com/libfuse/libfuse/blob/d30247c36dadd386b994cd47ad84351ae68cc94c/example/ioctl.c

Cargo.toml

@@ -29,7 +29,7 @@ clap = { version = "4.4", features = ["cargo", "derive"] }
 bincode = "1.3.1"
 serde = { version = "1.0.102", features = ["std", "derive"] }
 tempfile = "3.10.1"
-nix = { version = "0.28.0", features = ["poll", "fs"] }
+nix = { version = "0.28.0", features = ["poll", "fs", "ioctl"] }
 
 [build-dependencies]
 pkg-config = { version = "0.3.14", optional = true }
@@ -77,3 +77,7 @@ required-features = ["abi-7-12"]
 [[example]]
 name = "notify_inval_inode"
 required-features = ["abi-7-12"]
+
+[[example]]
+name = "ioctl"
+required-features = ["abi-7-11"]

examples/ioctl.rs

@@ -0,0 +1,209 @@
+// This example requires fuse 7.11 or later. Run with:
+//
+// cargo run --example ioctl --features abi-7-11 /tmp/foobar
+
+use clap::{crate_version, Arg, ArgAction, Command};
+use fuser::{
+ FileAttr, FileType, Filesystem, MountOption, ReplyAttr, ReplyData, ReplyDirectory, ReplyEntry,
+ Request,
+};
+use libc::{EINVAL, ENOENT};
+use log::debug;
+use std::ffi::OsStr;
+use std::time::{Duration, UNIX_EPOCH};
+
+const TTL: Duration = Duration::from_secs(1); // 1 second
+
+struct FiocFS {
+ content: Vec<u8>,
+ root_attr: FileAttr,
+ fioc_file_attr: FileAttr,
+}
+
+impl FiocFS {
+ fn new() -> Self {
+ let uid = unsafe { libc::getuid() };
+ let gid = unsafe { libc::getgid() };
+
+ let root_attr = FileAttr {
+ ino: 1,
+ size: 0,
+ blocks: 0,
+ atime: UNIX_EPOCH, // 1970-01-01 00:00:00
+ mtime: UNIX_EPOCH,
+ ctime: UNIX_EPOCH,
+ crtime: UNIX_EPOCH,
+ kind: FileType::Directory,
+ perm: 0o755,
+ nlink: 2,
+ uid,
+ gid,
+ rdev: 0,
+ flags: 0,
+ blksize: 512,
+ };
+
+ let fioc_file_attr = FileAttr {
+ ino: 2,
+ size: 0,
+ blocks: 1,
+ atime: UNIX_EPOCH, // 1970-01-01 00:00:00
+ mtime: UNIX_EPOCH,
+ ctime: UNIX_EPOCH,
+ crtime: UNIX_EPOCH,
+ kind: FileType::RegularFile,
+ perm: 0o644,
+ nlink: 1,
+ uid,
+ gid,
+ rdev: 0,
+ flags: 0,
+ blksize: 512,
+ };
+
+ Self {
+ content: vec![],
+ root_attr,
+ fioc_file_attr,
+ }
+ }
+}
+
+impl Filesystem for FiocFS {
+ fn lookup(&mut self, _req: &Request, parent: u64, name: &OsStr, reply: ReplyEntry) {
+ if parent == 1 && name.to_str() == Some("fioc") {
+ reply.entry(&TTL, &self.fioc_file_attr, 0);
+ } else {
+ reply.error(ENOENT);
+ }
+ }
+
+ fn getattr(&mut self, _req: &Request, ino: u64, _fh: Option<u64>, reply: ReplyAttr) {
+ match ino {
+ 1 => reply.attr(&TTL, &self.root_attr),
+ 2 => reply.attr(&TTL, &self.fioc_file_attr),
+ _ => reply.error(ENOENT),
+ }
+ }
+
+ fn read(
+ &mut self,
+ _req: &Request,
+ ino: u64,
+ _fh: u64,
+ offset: i64,
+ _size: u32,
+ _flags: i32,
+ _lock: Option<u64>,
+ reply: ReplyData,
+ ) {
+ if ino == 2 {
+ reply.data(&self.content[offset as usize..])
+ } else {
+ reply.error(ENOENT);
+ }
+ }
+
+ fn readdir(
+ &mut self,
+ _req: &Request,
+ ino: u64,
+ _fh: u64,
+ offset: i64,
+ mut reply: ReplyDirectory,
+ ) {
+ if ino != 1 {
+ reply.error(ENOENT);
+ return;
+ }
+
+ let entries = vec![
+ (1, FileType::Directory, "."),
+ (1, FileType::Directory, ".."),
+ (2, FileType::RegularFile, "fioc"),
+ ];
+
+ for (i, entry) in entries.into_iter().enumerate().skip(offset as usize) {
+ // i + 1 means the index of the next entry
+ if reply.add(entry.0, (i + 1) as i64, entry.1, entry.2) {
+ break;
+ }
+ }
+ reply.ok();
+ }
+
+ fn ioctl(
+ &mut self,
+ _req: &Request<'_>,
+ ino: u64,
+ _fh: u64,
+ _flags: u32,
+ cmd: u32,
+ in_data: &[u8],
+ _out_size: u32,
+ reply: fuser::ReplyIoctl,
+ ) {
+ if ino != 2 {
+ reply.error(EINVAL);
+ return;
+ }
+
+ const FIOC_GET_SIZE: u64 = nix::request_code_read!('E', 0, std::mem::size_of::<usize>());
+ const FIOC_SET_SIZE: u64 = nix::request_code_write!('E', 1, std::mem::size_of::<usize>());
+
+ match cmd.into() {
+ FIOC_GET_SIZE => {
+ let size_bytes = self.content.len().to_ne_bytes();
+ reply.ioctl(0, &size_bytes);
+ }
+ FIOC_SET_SIZE => {
+ let new_size = usize::from_ne_bytes(in_data.try_into().unwrap());
+ self.content = vec![0_u8; new_size];
+ reply.ioctl(0, &[]);
+ }
+ _ => {
+ debug!("unknown ioctl: {}", cmd);
+ reply.error(EINVAL);
+ }
+ }
+ }
+}
+
+fn main() {
+ let matches = Command::new("hello")
+ .version(crate_version!())
+ .author("Colin Marc")
+ .arg(
+ Arg::new("MOUNT_POINT")
+ .required(true)
+ .index(1)
+ .help("Act as a client, and mount FUSE at given path"),
+ )
+ .arg(
+ Arg::new("auto_unmount")
+ .long("auto_unmount")
+ .action(ArgAction::SetTrue)
+ .help("Automatically unmount on process exit"),
+ )
+ .arg(
+ Arg::new("allow-root")
+ .long("allow-root")
+ .action(ArgAction::SetTrue)
+ .help("Allow root user to access filesystem"),
+ )
+ .get_matches();
+
+ env_logger::init();
+
+ let mountpoint = matches.get_one::<String>("MOUNT_POINT").unwrap();
+ let mut options = vec![MountOption::FSName("fioc".to_string())];
+ if matches.get_flag("auto_unmount") {
+ options.push(MountOption::AutoUnmount);
+ }
+ if matches.get_flag("allow-root") {
+ options.push(MountOption::AllowRoot);
+ }
+
+ let fs = FiocFS::new();
+ fuser::mount2(fs, mountpoint, &options).unwrap();
+}