1 files changed, 253 insertions, 0 deletions
diff --git a/src/fuse/ops/dir.rs b/src/fuse/ops/dir.rs
new file mode 100644
index 0000000..76267ec
--- /dev/null
+++ b/src/fuse/ops/dir.rs
@@ -0,0 +1,253 @@
+use std::{
+    convert::Infallible,
+    ffi::{CStr, OsStr},
+    marker::PhantomData,
+    os::unix::ffi::OsStrExt,
+};
+
+use crate::fuse::{
+    io::{Entry, EntryType, Interruptible, Known, Stat},
+    private_trait::Sealed,
+    Done, Operation, Reply, Request,
+};
+
+use super::{c_to_os, FromRequest};
+use crate::{proto, Errno, Ino, Ttl};
+use bytemuck::{bytes_of, Zeroable};
+use bytes::BufMut;
+use nix::sys::stat::SFlag;
+
+pub enum Lookup {}
+pub enum Readdir {}
+pub struct BufferedReaddir<B>(Infallible, PhantomData<B>);
+
+pub struct ReaddirState<B> {
+    max_read: usize,
+    is_plus: bool,
+    buffer: B,
+}
+
+impl Sealed for Lookup {}
+impl Sealed for Readdir {}
+impl<B> Sealed for BufferedReaddir<B> {}
+
+impl<'o> Operation<'o> for Lookup {
+    type RequestBody = &'o CStr; // name()
+    type ReplyTail = ();
+}
+
+impl<'o> Operation<'o> for Readdir {
+    type RequestBody = proto::OpcodeSelect<
+        &'o proto::ReaddirPlusIn,
+        &'o proto::ReaddirIn,
+        { proto::Opcode::ReaddirPlus as u32 },
+    >;
+
+    type ReplyTail = ReaddirState<()>;
+}
+
+impl<'o, B> Operation<'o> for BufferedReaddir<B> {
+    type RequestBody = (); // Never actually created
+    type ReplyTail = ReaddirState<B>;
+}
+
+impl<'o> Request<'o, Lookup> {
+    /// Returns the name of the entry being looked up in this directory.
+    pub fn name(&self) -> &OsStr {
+        c_to_os(self.body)
+    }
+}
+
+impl<'o> Reply<'o, Lookup> {
+    /// The requested entry was found. The FUSE client will become aware of the found inode if
+    /// it wasn't before. This result may be cached by the client for up to the given TTL.
+    pub fn found(self, entry: impl Known, ttl: Ttl) -> Done<'o> {
+        let (attrs, attrs_ttl) = entry.inode().attrs();
+        let attrs = attrs.finish(entry.inode());
+
+        let done = self.single(&make_entry((entry.inode().ino(), ttl), (attrs, attrs_ttl)));
+        entry.unveil();
+
+        done
+    }
+
+    /// The requested entry was not found in this directory. The FUSE clint may include this
+    /// response in negative cache for up to the given TTL.
+    pub fn not_found(self, ttl: Ttl) -> Done<'o> {
+        self.single(&make_entry(
+            (Ino::NULL, ttl),
+            (Zeroable::zeroed(), Ttl::NULL),
+        ))
+    }
+
+    /// The requested entry was not found in this directory, but unlike [`Reply::not_found()`]
+    /// this does not report back a TTL to the FUSE client. The client should not cache the
+    /// response.
+    pub fn not_found_uncached(self) -> Done<'o> {
+        self.fail(Errno::ENOENT)
+    }
+}
+
+impl<'o> Request<'o, Readdir> {
+    pub fn handle(&self) -> u64 {
+        self.read_in().fh
+    }
+
+    /// Returns the base offset in the directory stream to read from.
+    pub fn offset(&self) -> u64 {
+        self.read_in().offset
+    }
+
+    pub fn size(&self) -> u32 {
+        self.read_in().size
+    }
+
+    fn read_in(&self) -> &proto::ReadIn {
+        use proto::OpcodeSelect::*;
+
+        match &self.body {
+            Match(readdir_plus) => &readdir_plus.read_in,
+            Alt(readdir) => &readdir.read_in,
+        }
+    }
+}
+
+impl<'o> Reply<'o, Readdir> {
+    pub fn buffered<B>(self, buffer: B) -> Reply<'o, BufferedReaddir<B>>
+    where
+        B: BufMut + AsRef<[u8]>,
+    {
+        assert!(buffer.as_ref().is_empty());
+
+        let ReaddirState {
+            max_read,
+            is_plus,
+            buffer: (),
+        } = self.tail;
+
+        Reply {
+            session: self.session,
+            unique: self.unique,
+            tail: ReaddirState {
+                max_read,
+                is_plus,
+                buffer,
+            },
+        }
+    }
+}
+
+impl<'o, B: BufMut + AsRef<[u8]>> Reply<'o, BufferedReaddir<B>> {
+    pub fn entry(mut self, entry: Entry<impl Known>) -> Interruptible<'o, BufferedReaddir<B>, ()> {
+        let entry_header_len = if self.tail.is_plus {
+            std::mem::size_of::<proto::DirentPlus>()
+        } else {
+            std::mem::size_of::<proto::Dirent>()
+        };
+
+        let name = entry.name.as_bytes();
+        let padding_len = dirent_pad_bytes(entry_header_len + name.len());
+
+        let buffer = &mut self.tail.buffer;
+        let remaining = buffer
+            .remaining_mut()
+            .min(self.tail.max_read - buffer.as_ref().len());
+
+        let record_len = entry_header_len + name.len() + padding_len;
+        if remaining < record_len {
+            if buffer.as_ref().is_empty() {
+                log::error!("Buffer for readdir req #{} is too small", self.unique);
+                return Interruptible::Interrupted(self.fail(Errno::ENOBUFS));
+            }
+
+            return Interruptible::Interrupted(self.end());
+        }
+
+        let inode = entry.inode.inode();
+        let entry_type = match inode.inode_type() {
+            EntryType::Fifo => SFlag::S_IFIFO,
+            EntryType::CharacterDevice => SFlag::S_IFCHR,
+            EntryType::Directory => SFlag::S_IFDIR,
+            EntryType::BlockDevice => SFlag::S_IFBLK,
+            EntryType::File => SFlag::S_IFREG,
+            EntryType::Symlink => SFlag::S_IFLNK,
+            EntryType::Socket => SFlag::S_IFSOCK,
+        };
+
+        let ino = inode.ino();
+        let dirent = proto::Dirent {
+            ino: ino.as_raw(),
+            off: entry.offset,
+            namelen: name.len().try_into().unwrap(),
+            entry_type: entry_type.bits() >> 12,
+        };
+
+        enum Ent {
+            Dirent(proto::Dirent),
+            DirentPlus(proto::DirentPlus),
+        }
+
+        let ent = if self.tail.is_plus {
+            let (attrs, attrs_ttl) = inode.attrs();
+            let attrs = attrs.finish(inode);
+            let entry_out = make_entry((ino, entry.ttl), (attrs, attrs_ttl));
+
+            if name != ".".as_bytes() && name != "..".as_bytes() {
+                entry.inode.unveil();
+            }
+
+            Ent::DirentPlus(proto::DirentPlus { entry_out, dirent })
+        } else {
+            Ent::Dirent(dirent)
+        };
+
+        let entry_header = match &ent {
+            Ent::Dirent(dirent) => bytes_of(dirent),
+            Ent::DirentPlus(dirent_plus) => bytes_of(dirent_plus),
+        };
+
+        buffer.put_slice(entry_header);
+        buffer.put_slice(name);
+        buffer.put_slice(&[0; 7][..padding_len]);
+
+        if remaining - record_len >= entry_header.len() + (1 << proto::DIRENT_ALIGNMENT_BITS) {
+            Interruptible::Completed(self, ())
+        } else {
+            Interruptible::Interrupted(self.end())
+        }
+    }
+
+    pub fn end(self) -> Done<'o> {
+        self.inner(|this| this.tail.buffer.as_ref())
+    }
+}
+
+impl<'o> FromRequest<'o, Readdir> for ReaddirState<()> {
+    fn from_request(request: &Request<'o, Readdir>) -> Self {
+        ReaddirState {
+            max_read: request.size() as usize,
+            is_plus: matches!(request.body, proto::OpcodeSelect::Match(_)),
+            buffer: (),
+        }
+    }
+}
+
+fn make_entry(
+    (Ino(ino), entry_ttl): (Ino, Ttl),
+    (attrs, attr_ttl): (proto::Attrs, Ttl),
+) -> proto::EntryOut {
+    proto::EntryOut {
+        nodeid: ino,
+        generation: 0, //TODO
+        entry_valid: entry_ttl.seconds,
+        attr_valid: attr_ttl.seconds,
+        entry_valid_nsec: entry_ttl.nanoseconds,
+        attr_valid_nsec: attr_ttl.nanoseconds,
+        attr: attrs,
+    }
+}
+
+fn dirent_pad_bytes(entry_len: usize) -> usize {
+    const ALIGN_MASK: usize = (1 << proto::DIRENT_ALIGNMENT_BITS) - 1;
+    ((entry_len + ALIGN_MASK) & !ALIGN_MASK) - entry_len
+}