miscellaneous fixes

tee/kernel/src/error.rs

@@ -109,11 +109,13 @@ pub enum ErrorKind {
     AddrInUse = 98,
     AddrNotAvail = 99,
     NetUnreach = 101,
+    ConnAborted = 103,
     ConnReset = 104,
     IsConn = 106,
     NotConn = 107,
     TimedOut = 110,
     ConnRefused = 111,
+    Already = 114,
     InProgress = 115,
     RestartNoIntr = 512,
     RestartRestartblock = 516,

tee/kernel/src/fs/fd.rs

@@ -896,7 +896,7 @@ pub trait OpenFileDescription: Send + Sync + 'static {
         &self,
         vm: &VirtualMemory,
         abi: Abi,
-        msg_hdr: &mut MsgHdr,
+        msg_hdr: MsgHdr,
         flags: SendMsgFlags,
         fdtable: &FileDescriptorTable,
         ctx: &FileAccessContext,

tee/kernel/src/fs/fd/epoll.rs

@@ -521,6 +521,12 @@ impl EventCounter {
     }
 }
 
+impl Default for EventCounter {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 pub struct AtomicEventCounter(AtomicU64);
 
 impl AtomicEventCounter {

tee/kernel/src/fs/fd/mem.rs

@@ -5,7 +5,7 @@ use async_trait::async_trait;
 use x86_64::structures::paging::{PageSize, Size4KiB};
 
 use crate::{
-    error::Result,
+    error::{Result, ensure, err},
     fs::{
         FileSystem,
         fd::{
@@ -20,7 +20,8 @@ use crate::{
     user::{
         futex::Futexes,
         syscall::args::{
-            FileMode, FileType, FileTypeAndMode, MemfdCreateFlags, OpenFlags, Seals, Stat, Timespec,
+            FileMode, FileType, FileTypeAndMode, MemfdCreateFlags, OpenFlags, Seals, Stat,
+            Timespec, Whence,
         },
         thread::{Gid, Uid},
     },
@@ -153,6 +154,43 @@ impl OpenFileDescription for MemFd {
         guard.buffer.truncate(length)
     }
 
+    fn seek(&self, offset: usize, whence: Whence, _: &mut FileAccessContext) -> Result<usize> {
+        let mut guard = self.internal.lock();
+
+        match whence {
+            Whence::Set => guard.cursor_idx = offset,
+            Whence::Cur => {
+                guard.cursor_idx = guard
+                    .cursor_idx
+                    .checked_add_signed(offset as isize)
+                    .ok_or(err!(Inval))?
+            }
+            Whence::End => {
+                let size = guard.buffer.len();
+                guard.cursor_idx = size
+                    .checked_add_signed(offset as isize)
+                    .ok_or(err!(Inval))?
+            }
+            Whence::Data => {
+                // Ensure that `offset` doesn't point past the file.
+                ensure!(offset < guard.buffer.len(), NxIo);
+
+                // We don't support holes so we always jump to `offset`.
+                guard.cursor_idx = offset;
+            }
+            Whence::Hole => {
+                let size = guard.buffer.len();
+
+                // Ensure that `offset` doesn't point past the file.
+                ensure!(offset < size, NxIo);
+
+                // We don't support holes so we always jump to the end of the file.
+                guard.cursor_idx = size;
+            }
+        }
+        Ok(guard.cursor_idx)
+    }
+
     fn get_page(&self, page_idx: usize, shared: bool) -> Result<KernelPage> {
         let mut guard = self.internal.lock();
         guard.buffer.get_page(page_idx, shared)

tee/kernel/src/fs/fd/unix_socket/dgram.rs

@@ -469,7 +469,12 @@ impl OpenFileDescription for DgramUnixSocket {
         }
         drop(cmsg_builder);
 
-        Ok(written)
+        let len = if flags.contains(RecvMsgFlags::TRUNC) {
+            len
+        } else {
+            written
+        };
+        Ok(len)
     }
 
     fn write(&self, buf: &dyn WriteBuf, ctx: &FileAccessContext) -> Result<usize> {
@@ -507,7 +512,7 @@ impl OpenFileDescription for DgramUnixSocket {
         &self,
         vm: &VirtualMemory,
         abi: Abi,
-        msg_hdr: &mut MsgHdr,
+        mut msg_hdr: MsgHdr,
         flags: SendMsgFlags,
         fdtable: &FileDescriptorTable,
         ctx: &FileAccessContext,