chore: Fix typos and add various comments

rosenpass/src/api/boilerplate/message_type.rs

@@ -6,6 +6,7 @@ use crate::RosenpassError::{self, InvalidApiMessageType};
 
 pub type RawMsgType = u128;
 
+// constants generated by gen-ipc-msg-types:
 // hash domain hash of: Rosenpass IPC API -> Rosenpass Protocol Server -> Ping Request
 pub const PING_REQUEST: RawMsgType =
     RawMsgType::from_le_bytes(hex!("2397 3ecc c441 704d    0b02 ea31 45d3 4999"));
@@ -46,7 +47,7 @@ impl MessageAttributes for ResponseMsgType {
 impl TryFrom<RawMsgType> for RequestMsgType {
     type Error = RosenpassError;
 
-    fn try_from(value: u128) -> Result<Self, Self::Error> {
+    fn try_from(value: RawMsgType) -> Result<Self, Self::Error> {
         use RequestMsgType as E;
         Ok(match value {
             self::PING_REQUEST => E::Ping,
@@ -67,7 +68,7 @@ impl From<RequestMsgType> for RawMsgType {
 impl TryFrom<RawMsgType> for ResponseMsgType {
     type Error = RosenpassError;
 
-    fn try_from(value: u128) -> Result<Self, Self::Error> {
+    fn try_from(value: RawMsgType) -> Result<Self, Self::Error> {
         use ResponseMsgType as E;
         Ok(match value {
             self::PING_RESPONSE => E::Ping,

rosenpass/src/api/cli.rs

@@ -10,7 +10,7 @@ use super::config::ApiConfig;
 #[derive(Args, Debug)]
 pub struct ApiCli {
     /// Where in the file-system to create the unix socket the rosenpass API will be listening for
-    /// connections on
+    /// connections on.
     #[arg(long)]
     api_listen_path: Vec<PathBuf>,
 

rosenpass/src/api/mio/manager.rs

@@ -70,6 +70,8 @@ impl MioManager {
         token_dispenser: &mut MioTokenDispenser,
     ) -> io::Result<()> {
         // Accept connection until the socket would block or returns another error
+        // TODO: This currently only adds connections--we eventually need the ability to remove
+        // them as well, see the note in connection.rs
         loop {
             match nonblocking_handle_io_errors(|| self.listeners[idx].accept())? {
                 None => break,

util/src/fd.rs

@@ -17,6 +17,8 @@ pub fn claim_fd(fd: RawFd) -> rustix::io::Result<OwnedFd> {
 }
 
 pub fn mask_fd(fd: RawFd) -> rustix::io::Result<()> {
+    // Safety: because the OwnedFd resulting from OwnedFd::from_raw_fd is wrapped in a Forgetting,
+    // it never gets dropped, meaning that fd is never closed and thus outlives the OwnedFd
     let mut owned = Forgetting::new(unsafe { OwnedFd::from_raw_fd(fd) });
     clone_fd_to_cloexec(open_nullfd()?, &mut owned)
 }

util/src/length_prefix_encoding/decoder.rs

@@ -19,7 +19,7 @@ pub enum SanityError {
 }
 
 #[derive(Error, Debug)]
-#[error("Message too lage ({msg_size} bytes) for buffer ({buf_size} bytes)")]
+#[error("Message too large ({msg_size} bytes) for buffer ({buf_size} bytes)")]
 pub struct MessageTooLargeError {
     msg_size: usize,
     buf_size: usize,
@@ -132,7 +132,7 @@ impl<Buf: BorrowMut<[u8]>> LengthPrefixDecoder<Buf> {
         Ok(match self.next_slice_to_write_to()? {
             // Read some bytes; any MessageTooLargeError in the call to self.message_mut() is
             // ignored to ensure this function changes no state upon errors; the user should rerun
-            // the function and colect the MessageTooLargeError on the following invocation
+            // the function and collect the MessageTooLargeError on the following invocation
             Some(buf) => {
                 let bytes_read = r.read(buf)?;
                 self.advance(bytes_read).unwrap();

util/src/zerocopy/ref_maker.rs

@@ -57,21 +57,22 @@ impl<B: ByteSlice, T> RefMaker<B, T> {
         Ok(Self::from_prefix_with_tail(self)?.0)
     }
 
-    pub fn from_suffix_with_tail(self) -> anyhow::Result<(Self, B)> {
+    pub fn from_suffix_with_head(self) -> anyhow::Result<(Self, B)> {
         self.ensure_fit()?;
         let point = self.bytes().len() - Self::target_size();
         let (head, tail) = self.buf.split_at(point);
-        Ok((Self::new(head), tail))
+        Ok((Self::new(tail), head))
     }
 
     pub fn split_suffix(self) -> anyhow::Result<(Self, Self)> {
         self.ensure_fit()?;
-        let (head, tail) = self.buf.split_at(Self::target_size());
+        let point = self.bytes().len() - Self::target_size();
+        let (head, tail) = self.buf.split_at(point);
         Ok((Self::new(head), Self::new(tail)))
     }
 
     pub fn from_suffix(self) -> anyhow::Result<Self> {
-        Ok(Self::from_suffix_with_tail(self)?.0)
+        Ok(Self::from_suffix_with_head(self)?.0)
     }
 
     pub fn bytes(&self) -> &[u8] {

util/src/zerocopy/zerocopy_slice_ext.rs

@@ -16,7 +16,7 @@ pub trait ZerocopySliceExt: Sized + ByteSlice {
     }
 
     fn zk_parse_suffix<T>(self) -> anyhow::Result<Ref<Self, T>> {
-        self.zk_ref_maker().from_prefix()?.parse()
+        self.zk_ref_maker().from_suffix()?.parse()
     }
 }
 
@@ -31,8 +31,8 @@ pub trait ZerocopyMutSliceExt: ZerocopySliceExt + Sized + ByteSliceMut {
         self.zk_ref_maker().from_prefix()?.make_zeroized()
     }
 
-    fn zk_zeroized_from_suffic<T>(self) -> anyhow::Result<Ref<Self, T>> {
-        self.zk_ref_maker().from_prefix()?.make_zeroized()
+    fn zk_zeroized_from_suffix<T>(self) -> anyhow::Result<Ref<Self, T>> {
+        self.zk_ref_maker().from_suffix()?.make_zeroized()
     }
 }