fix: insufficient buf size when reading windows named pipe message

src/sys/windows/named_pipe.rs

@@ -7,14 +7,14 @@ use std::sync::{Arc, Mutex};
 use std::{fmt, mem, slice};
 
 use windows_sys::Win32::Foundation::{
-    ERROR_BROKEN_PIPE, ERROR_IO_INCOMPLETE, ERROR_IO_PENDING, ERROR_NO_DATA, ERROR_PIPE_CONNECTED,
-    ERROR_PIPE_LISTENING, HANDLE, INVALID_HANDLE_VALUE,
+    ERROR_BROKEN_PIPE, ERROR_IO_INCOMPLETE, ERROR_IO_PENDING, ERROR_MORE_DATA, ERROR_NO_DATA,
+    ERROR_PIPE_CONNECTED, ERROR_PIPE_LISTENING, HANDLE, INVALID_HANDLE_VALUE,
 };
 use windows_sys::Win32::Storage::FileSystem::{
     ReadFile, WriteFile, FILE_FLAG_FIRST_PIPE_INSTANCE, FILE_FLAG_OVERLAPPED, PIPE_ACCESS_DUPLEX,
 };
 use windows_sys::Win32::System::Pipes::{
-    ConnectNamedPipe, CreateNamedPipeW, DisconnectNamedPipe, PIPE_TYPE_BYTE,
+    ConnectNamedPipe, CreateNamedPipeW, DisconnectNamedPipe, PeekNamedPipe, PIPE_TYPE_BYTE,
     PIPE_UNLIMITED_INSTANCES,
 };
 use windows_sys::Win32::System::IO::{
@@ -307,6 +307,25 @@ impl Inner {
             Ok(transferred as usize)
         }
     }
+
+    /// Calls the `PeekNamedPipe` function to get the remaining size of message in NamedPipe
+    #[inline]
+    unsafe fn remaining_size(&self) -> io::Result<usize> {
+        let mut remaining = 0;
+        let r = PeekNamedPipe(
+            self.handle.raw(),
+            std::ptr::null_mut(),
+            0,
+            std::ptr::null_mut(),
+            std::ptr::null_mut(),
+            &mut remaining,
+        );
+        if r == 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(remaining as usize)
+        }
+    }
 }
 
 #[test]
@@ -349,6 +368,7 @@ enum State {
     Pending(Vec<u8>, usize),
     Ok(Vec<u8>, usize),
     Err(io::Error),
+    InsufficientBufferSize(Vec<u8>, usize),
 }
 
 // Odd tokens are for named pipes
@@ -535,7 +555,7 @@ impl<'a> Read for &'a NamedPipe {
             }
 
             // We previously read something into `data`, try to copy out some
-            // data. If we copy out all the data schedule a new read and
+            // data. If we copy out all the data, schedule a new read
             // otherwise store the buffer to get read later.
             State::Ok(data, cur) => {
                 let n = {
@@ -552,6 +572,10 @@ impl<'a> Read for &'a NamedPipe {
                 Ok(n)
             }
 
+            // We scheduled another read with a bigger buffer after the first read (see `read_done`)
+            // This is not possible in theory, just like `State::None` case, but return would block for now.
+            State::InsufficientBufferSize(..) => Err(would_block()),
+
             // Looks like an in-flight read hit an error, return that here while
             // we schedule a new one.
             State::Err(e) => {
@@ -703,19 +727,25 @@ impl Inner {
     /// scheduled.
     fn schedule_read(me: &Arc<Inner>, io: &mut Io, events: Option<&mut Vec<Event>>) -> bool {
         // Check to see if a read is already scheduled/completed
-        match io.read {
-            State::None => {}
-            _ => return true,
-        }
+
+        let mut buf = match mem::replace(&mut io.read, State::None) {
+            State::None => me.get_buffer(),
+            State::InsufficientBufferSize(mut buf, rem) => {
+                buf.reserve_exact(rem);
+                buf
+            }
+            e @ _ => {
+                io.read = e;
+                return true;
+            }
+        };
 
         // Allocate a buffer and schedule the read.
-        let mut buf = me.get_buffer();
         let e = unsafe {
             let overlapped = me.read.as_ptr() as *mut _;
             let slice = slice::from_raw_parts_mut(buf.as_mut_ptr(), buf.capacity());
-            me.read_overlapped(slice, overlapped)
+            me.read_overlapped(&mut slice[buf.len()..], overlapped)
         };
-
         match e {
             // See `NamedPipe::connect` above for the rationale behind `forget`
             Ok(_) => {
@@ -874,9 +904,25 @@ fn read_done(status: &OVERLAPPED_ENTRY, events: Option<&mut Vec<Event>>) {
         match me.result(status.overlapped()) {
             Ok(n) => {
                 debug_assert_eq!(status.bytes_transferred() as usize, n);
-                buf.set_len(status.bytes_transferred() as usize);
+                // Extend the len depending on the initial len is necessary
+                // when we call `ReadFile` again after resizing
+                // our internal buffer
+                buf.set_len(buf.len() + status.bytes_transferred() as usize);
                 io.read = State::Ok(buf, 0);
             }
+            Err(e) if e.raw_os_error() == Some(ERROR_MORE_DATA as i32) => {
+                match me.remaining_size() {
+                    Ok(rem) => {
+                        buf.set_len(status.bytes_transferred() as usize);
+                        io.read = State::InsufficientBufferSize(buf, rem);
+                        Inner::schedule_read(&me, &mut io, None);
+                        return;
+                    }
+                    Err(e) => {
+                        io.read = State::Err(e);
+                    }
+                }
+            }
             Err(e) => {
                 debug_assert_eq!(status.bytes_transferred(), 0);
                 io.read = State::Err(e);

tests/win_named_pipe.rs

@@ -1,15 +1,24 @@
 #![cfg(all(windows, feature = "os-poll", feature = "os-ext"))]
 
+use std::ffi::OsStr;
 use std::fs::OpenOptions;
 use std::io::{self, Read, Write};
+use std::os::windows::ffi::OsStrExt;
 use std::os::windows::fs::OpenOptionsExt;
-use std::os::windows::io::{FromRawHandle, IntoRawHandle};
+use std::os::windows::io::{FromRawHandle, IntoRawHandle, RawHandle};
 use std::time::Duration;
 
 use mio::windows::NamedPipe;
 use mio::{Events, Interest, Poll, Token};
 use rand::Rng;
-use windows_sys::Win32::{Foundation::ERROR_NO_DATA, Storage::FileSystem::FILE_FLAG_OVERLAPPED};
+use windows_sys::Win32::Foundation::ERROR_NO_DATA;
+use windows_sys::Win32::Storage::FileSystem::{
+    CreateFileW, FILE_FLAG_FIRST_PIPE_INSTANCE, FILE_FLAG_OVERLAPPED, OPEN_EXISTING,
+    PIPE_ACCESS_DUPLEX,
+};
+use windows_sys::Win32::System::Pipes::{
+    CreateNamedPipeW, PIPE_READMODE_MESSAGE, PIPE_TYPE_MESSAGE, PIPE_UNLIMITED_INSTANCES,
+};
 
 fn _assert_kinds() {
     fn _assert_send<T: Send>() {}
@@ -43,6 +52,38 @@ fn client(name: &str) -> NamedPipe {
     unsafe { NamedPipe::from_raw_handle(file.into_raw_handle()) }
 }
 
+fn pipe_msg_mode() -> (NamedPipe, NamedPipe) {
+    let num: u64 = rand::thread_rng().gen();
+    let name = format!(r"\\.\pipe\my-pipe-{}", num);
+    let name: Vec<_> = OsStr::new(&name).encode_wide().chain(Some(0)).collect();
+    unsafe {
+        let h = CreateNamedPipeW(
+            name.as_ptr(),
+            PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE | FILE_FLAG_OVERLAPPED,
+            PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE,
+            PIPE_UNLIMITED_INSTANCES,
+            65536,
+            65536,
+            0,
+            std::ptr::null_mut(),
+        );
+
+        let server = NamedPipe::from_raw_handle(h as RawHandle);
+
+        let h = CreateFileW(
+            name.as_ptr(),
+            PIPE_ACCESS_DUPLEX,
+            0,
+            std::ptr::null_mut(),
+            OPEN_EXISTING,
+            FILE_FLAG_OVERLAPPED,
+            0,
+        );
+        let client = NamedPipe::from_raw_handle(h as RawHandle);
+        (server, client)
+    }
+}
+
 fn pipe() -> (NamedPipe, NamedPipe) {
     let (pipe, name) = server();
     (pipe, client(&name))
@@ -108,6 +149,45 @@ fn write_then_read() {
     assert_eq!(&buf[..4], b"1234");
 }
 
+#[test]
+fn read_sz_greater_than_default_buf_size() {
+    let (mut server, mut client) = pipe_msg_mode();
+    let mut poll = t!(Poll::new());
+    t!(poll.registry().register(
+        &mut server,
+        Token(0),
+        Interest::READABLE | Interest::WRITABLE,
+    ));
+    t!(poll.registry().register(
+        &mut client,
+        Token(1),
+        Interest::READABLE | Interest::WRITABLE,
+    ));
+
+    let mut events = Events::with_capacity(128);
+    let msg = (0..4106)
+        .map(|e| e.to_string())
+        .collect::<Vec<_>>()
+        .join("");
+
+    t!(poll.poll(&mut events, None));
+    assert_eq!(t!(client.write(msg.as_bytes())), 15314);
+
+    loop {
+        t!(poll.poll(&mut events, None));
+        let events = events.iter().collect::<Vec<_>>();
+        if let Some(event) = events.iter().find(|e| e.token() == Token(0)) {
+            if event.is_readable() {
+                break;
+            }
+        }
+    }
+
+    let mut buf = [0; 15314];
+    assert_eq!(t!(server.read(&mut buf)), 15314);
+    assert_eq!(&buf[..15314], msg.as_bytes());
+}
+
 #[test]
 fn connect_before_client() {
     let (mut server, name) = server();