diff --git a/src/libos/Enclave_config.xml b/src/libos/Enclave_config.xml
index 5f853be5..7d9f7639 100644
--- a/src/libos/Enclave_config.xml
+++ b/src/libos/Enclave_config.xml
@@ -3,7 +3,7 @@
   <ProdID>0</ProdID>
   <ISVSVN>0</ISVSVN>
   <StackMaxSize>0x100000</StackMaxSize>
-  <HeapMaxSize>0x1000000</HeapMaxSize>
+  <HeapMaxSize>0x2000000</HeapMaxSize>
   <TCSNum>8</TCSNum>
   <TCSPolicy>1</TCSPolicy>
   <DisableDebug>0</DisableDebug>
diff --git a/src/libos/src/fs/file.rs b/src/libos/src/fs/file.rs
index a56fb8a8..82ae1e5e 100644
--- a/src/libos/src/fs/file.rs
+++ b/src/libos/src/fs/file.rs
@@ -373,7 +373,7 @@ impl File for StdoutFile {
             atime: Timespec { sec: 0, nsec: 0 },
             mtime: Timespec { sec: 0, nsec: 0 },
             ctime: Timespec { sec: 0, nsec: 0 },
-            type_: FileType::File,
+            type_: FileType::CharDevice,
             mode: 0,
             nlinks: 0,
             uid: 0,
@@ -489,7 +489,7 @@ impl File for StdinFile {
             atime: Timespec { sec: 0, nsec: 0 },
             mtime: Timespec { sec: 0, nsec: 0 },
             ctime: Timespec { sec: 0, nsec: 0 },
-            type_: FileType::File,
+            type_: FileType::CharDevice,
             mode: 0,
             nlinks: 0,
             uid: 0,
diff --git a/src/libos/src/fs/io_multiplexing.rs b/src/libos/src/fs/io_multiplexing.rs
index 59e1c962..419a1ab8 100644
--- a/src/libos/src/fs/io_multiplexing.rs
+++ b/src/libos/src/fs/io_multiplexing.rs
@@ -1,5 +1,4 @@
 use super::*;
-use crate::syscall::AsSocket;
 use std::any::Any;
 use std::collections::btree_map::BTreeMap;
 use std::fmt;
diff --git a/src/libos/src/fs/mod.rs b/src/libos/src/fs/mod.rs
index e7e6a74e..ad6c7041 100644
--- a/src/libos/src/fs/mod.rs
+++ b/src/libos/src/fs/mod.rs
@@ -9,7 +9,8 @@ use super::*;
 pub use self::file::{File, FileRef, SgxFile, StdinFile, StdoutFile};
 pub use self::file_table::{FileDesc, FileTable};
 pub use self::inode_file::{INodeExt, INodeFile, ROOT_INODE};
-pub use self::socket_file::SocketFile;
+pub use self::socket_file::{SocketFile, AsSocket};
+pub use self::unix_socket::{UnixSocketFile, AsUnixSocket};
 use self::inode_file::OpenOptions;
 pub use self::pipe::Pipe;
 pub use self::io_multiplexing::*;
@@ -27,6 +28,7 @@ mod sgx_impl;
 mod io_multiplexing;
 mod access;
 mod null;
+mod unix_socket;
 
 
 pub fn do_open(path: &str, flags: u32, mode: u32) -> Result<FileDesc, Error> {
@@ -363,7 +365,7 @@ pub fn do_sendfile(
 
     let in_file = file_table.get(in_fd)?;
     let out_file = file_table.get(out_fd)?;
-    let mut buffer: [u8; 1024] = unsafe { uninitialized() };
+    let mut buffer: [u8; 1024 * 11] = unsafe { uninitialized() };
 
     let mut read_offset = match offset {
         Some(offset) => offset,
diff --git a/src/libos/src/fs/socket_file.rs b/src/libos/src/fs/socket_file.rs
index baaa87f8..7391c05b 100644
--- a/src/libos/src/fs/socket_file.rs
+++ b/src/libos/src/fs/socket_file.rs
@@ -90,7 +90,21 @@ impl File for SocketFile {
     }
 
     fn metadata(&self) -> Result<Metadata, Error> {
-        unimplemented!()
+        Ok(Metadata {
+            dev: 0,
+            inode: 0,
+            size: 0,
+            blk_size: 0,
+            blocks: 0,
+            atime: Timespec { sec: 0, nsec: 0 },
+            mtime: Timespec { sec: 0, nsec: 0 },
+            ctime: Timespec { sec: 0, nsec: 0 },
+            type_: FileType::Socket,
+            mode: 0,
+            nlinks: 0,
+            uid: 0,
+            gid: 0
+        })
     }
 
     fn set_len(&self, len: u64) -> Result<(), Error> {
@@ -113,3 +127,15 @@ impl File for SocketFile {
         self
     }
 }
+
+pub trait AsSocket {
+    fn as_socket(&self) -> Result<&SocketFile, Error>;
+}
+
+impl AsSocket for FileRef {
+    fn as_socket(&self) -> Result<&SocketFile, Error> {
+        self.as_any()
+            .downcast_ref::<SocketFile>()
+            .ok_or(Error::new(Errno::EBADF, "not a socket"))
+    }
+}
diff --git a/src/libos/src/fs/unix_socket.rs b/src/libos/src/fs/unix_socket.rs
new file mode 100644
index 00000000..6aeae486
--- /dev/null
+++ b/src/libos/src/fs/unix_socket.rs
@@ -0,0 +1,310 @@
+use super::*;
+use std::collections::btree_map::BTreeMap;
+use util::ring_buf::{RingBufReader, RingBufWriter, RingBuf};
+use std::sync::SgxMutex as Mutex;
+use alloc::prelude::ToString;
+use std::fmt;
+
+pub struct UnixSocketFile {
+    inner: Mutex<UnixSocket>
+}
+
+impl File for UnixSocketFile {
+    fn read(&self, buf: &mut [u8]) -> Result<usize, Error> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.read(buf)
+    }
+
+    fn write(&self, buf: &[u8]) -> Result<usize, Error> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.write(buf)
+    }
+
+    fn read_at(&self, _offset: usize, buf: &mut [u8]) -> Result<usize, Error> {
+        self.read(buf)
+    }
+
+    fn write_at(&self, _offset: usize, buf: &[u8]) -> Result<usize, Error> {
+        self.write(buf)
+    }
+
+    fn readv(&self, bufs: &mut [&mut [u8]]) -> Result<usize, Error> {
+        let mut inner = self.inner.lock().unwrap();
+        let mut total_len = 0;
+        for buf in bufs {
+            match inner.read(buf) {
+                Ok(len) => {
+                    total_len += len;
+                }
+                Err(_) if total_len != 0 => break,
+                Err(e) => return Err(e.into()),
+            }
+        }
+        Ok(total_len)
+    }
+
+    fn writev(&self, bufs: &[&[u8]]) -> Result<usize, Error> {
+        let mut inner = self.inner.lock().unwrap();
+        let mut total_len = 0;
+        for buf in bufs {
+            match inner.write(buf) {
+                Ok(len) => {
+                    total_len += len;
+                }
+                Err(_) if total_len != 0 => break,
+                Err(e) => return Err(e.into()),
+            }
+        }
+        Ok(total_len)
+    }
+
+    fn seek(&self, pos: SeekFrom) -> Result<off_t, Error> {
+        errno!(ESPIPE, "UnixSocket does not support seek")
+    }
+
+    fn metadata(&self) -> Result<Metadata, Error> {
+        Ok(Metadata {
+            dev: 0,
+            inode: 0,
+            size: 0,
+            blk_size: 0,
+            blocks: 0,
+            atime: Timespec { sec: 0, nsec: 0 },
+            mtime: Timespec { sec: 0, nsec: 0 },
+            ctime: Timespec { sec: 0, nsec: 0 },
+            type_: FileType::Socket,
+            mode: 0,
+            nlinks: 0,
+            uid: 0,
+            gid: 0
+        })
+    }
+
+    fn set_len(&self, len: u64) -> Result<(), Error> {
+        unimplemented!()
+    }
+
+    fn sync_all(&self) -> Result<(), Error> {
+        unimplemented!()
+    }
+
+    fn sync_data(&self) -> Result<(), Error> {
+        unimplemented!()
+    }
+
+    fn read_entry(&self) -> Result<String, Error> {
+        unimplemented!()
+    }
+
+    fn as_any(&self) -> &Any {
+        self
+    }
+}
+
+impl UnixSocketFile {
+    pub fn new(socket_type: c_int, protocol: c_int) -> Result<Self, Error> {
+        let inner = UnixSocket::new(socket_type, protocol)?;
+        Ok(UnixSocketFile { inner: Mutex::new(inner) })
+    }
+
+    pub fn bind(&self, path: impl AsRef<str>) -> Result<(), Error> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.bind(path)
+    }
+
+    pub fn listen(&self) -> Result<(), Error> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.listen()
+    }
+
+    pub fn accept(&self) -> Result<UnixSocketFile, Error> {
+        let mut inner = self.inner.lock().unwrap();
+        let new_socket = inner.accept()?;
+        Ok(UnixSocketFile { inner: Mutex::new(new_socket) })
+    }
+
+    pub fn connect(&self, path: impl AsRef<str>) -> Result<(), Error> {
+        let mut inner = self.inner.lock().unwrap();
+        inner.connect(path)
+    }
+}
+
+impl Debug for UnixSocketFile {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "UnixSocketFile {{ ... }}")
+    }
+}
+
+
+pub trait AsUnixSocket {
+    fn as_unix_socket(&self) -> Result<&UnixSocketFile, Error>;
+}
+
+impl AsUnixSocket for FileRef {
+    fn as_unix_socket(&self) -> Result<&UnixSocketFile, Error> {
+        self.as_any()
+            .downcast_ref::<UnixSocketFile>()
+            .ok_or(Error::new(Errno::EBADF, "not a unix socket"))
+    }
+}
+
+
+pub struct UnixSocket {
+    obj: Option<Arc<UnixSocketObject>>,
+    status: Status,
+}
+
+enum Status {
+    None,
+    Listening,
+    Connected(Channel),
+}
+
+impl UnixSocket {
+    /// C/S 1: Create a new unix socket
+    pub fn new(socket_type: c_int, protocol: c_int) -> Result<Self, Error> {
+        if socket_type == libc::SOCK_STREAM && protocol == 0 {
+            Ok(UnixSocket {
+                obj: None,
+                status: Status::None
+            })
+        } else {
+            errno!(ENOSYS, "unimplemented unix socket type")
+        }
+    }
+
+    /// Server 2: Bind the socket to a file system path
+    pub fn bind(&mut self, path: impl AsRef<str>) -> Result<(), Error> {
+        // TODO: check permission
+        if self.obj.is_some() {
+            return errno!(EINVAL, "The socket is already bound to an address.");
+        }
+        self.obj = Some(UnixSocketObject::create(path)?);
+        Ok(())
+    }
+
+    /// Server 3: Listen to a socket
+    pub fn listen(&mut self) -> Result<(), Error> {
+        self.status = Status::Listening;
+        Ok(())
+    }
+
+    /// Server 4: Accept a connection on listening. Non-blocking.
+    pub fn accept(&mut self) -> Result<UnixSocket, Error> {
+        match self.status {
+            Status::Listening => {}
+            _ => return errno!(EINVAL, "unix socket is not listening"),
+        };
+        let socket = self.obj.as_mut().unwrap().pop()
+            .ok_or(Error::new(EAGAIN, "no connections are present to be accepted"))?;
+        Ok(socket)
+    }
+
+    /// Client 2: Connect to a path
+    pub fn connect(&mut self, path: impl AsRef<str>) -> Result<(), Error> {
+        if let Status::Listening = self.status {
+            return errno!(EINVAL, "unix socket is listening?");
+        }
+        let obj = UnixSocketObject::get(path)
+            .ok_or(Error::new(EINVAL, "unix socket path not found"))?;
+        let (channel1, channel2) = Channel::new_pair();
+        self.status = Status::Connected(channel1);
+        obj.push(UnixSocket {
+            obj: Some(obj.clone()),
+            status: Status::Connected(channel2),
+        });
+        Ok(())
+    }
+
+    pub fn read(&self, buf: &mut [u8]) -> Result<usize, Error> {
+        if let Status::Connected(channel) = &self.status {
+            channel.reader.read(buf)
+        } else {
+            errno!(EBADF, "UnixSocket is not connected")
+        }
+    }
+
+    pub fn write(&self, buf: &[u8]) -> Result<usize, Error> {
+        if let Status::Connected(channel) = &self.status {
+            channel.writer.write(buf)
+        } else {
+            errno!(EBADF, "UnixSocket is not connected")
+        }
+    }
+}
+
+impl Drop for UnixSocket {
+    fn drop(&mut self) {
+        if let Status::Listening = self.status {
+            let path = &self.obj.as_ref().unwrap().path;
+            UnixSocketObject::remove(path);
+        }
+    }
+}
+
+pub struct UnixSocketObject {
+    path: String,
+    accepted_sockets: Mutex<VecDeque<UnixSocket>>,
+}
+
+impl UnixSocketObject {
+    fn push(&self, unix_socket: UnixSocket) {
+        let mut queue = self.accepted_sockets.lock().unwrap();
+        queue.push_back(unix_socket);
+    }
+    fn pop(&self) -> Option<UnixSocket> {
+        let mut queue = self.accepted_sockets.lock().unwrap();
+        queue.pop_front()
+    }
+    fn get(path: impl AsRef<str>) -> Option<Arc<Self>> {
+        let mut paths = UNIX_SOCKET_OBJS.lock().unwrap();
+        paths.get(path.as_ref()).map(|obj| obj.clone())
+    }
+    fn create(path: impl AsRef<str>) -> Result<Arc<Self>, Error> {
+        let mut paths = UNIX_SOCKET_OBJS.lock().unwrap();
+        if paths.contains_key(path.as_ref()) {
+            return errno!(EADDRINUSE, "unix socket path already exists");
+        }
+        let obj = Arc::new(UnixSocketObject {
+            path: path.as_ref().to_string(),
+            accepted_sockets: Mutex::new(VecDeque::new())
+        });
+        paths.insert(path.as_ref().to_string(), obj.clone());
+        Ok(obj)
+    }
+    fn remove(path: impl AsRef<str>) {
+        let mut paths = UNIX_SOCKET_OBJS.lock().unwrap();
+        paths.remove(path.as_ref());
+    }
+}
+
+struct Channel {
+    reader: RingBufReader,
+    writer: RingBufWriter
+}
+
+unsafe impl Send for Channel {}
+unsafe impl Sync for Channel {}
+
+impl Channel {
+    fn new_pair() -> (Channel, Channel) {
+        let buf1 = RingBuf::new(DEFAULT_BUF_SIZE);
+        let buf2 = RingBuf::new(DEFAULT_BUF_SIZE);
+        let channel1 = Channel {
+            reader: buf1.reader,
+            writer: buf2.writer,
+        };
+        let channel2 = Channel {
+            reader: buf2.reader,
+            writer: buf1.writer,
+        };
+        (channel1, channel2)
+    }
+}
+
+pub const DEFAULT_BUF_SIZE: usize = 1 * 1024 * 1024;
+
+lazy_static! {
+    static ref UNIX_SOCKET_OBJS: Mutex<BTreeMap<String, Arc<UnixSocketObject>>>
+        = Mutex::new(BTreeMap::new());
+}
diff --git a/src/libos/src/prelude.rs b/src/libos/src/prelude.rs
index 74235313..7cddd8ce 100644
--- a/src/libos/src/prelude.rs
+++ b/src/libos/src/prelude.rs
@@ -36,7 +36,7 @@ macro_rules! debug_trace {
 
 macro_rules! errno {
     ($errno: ident, $msg: expr) => {{
-        println!(
+        error!(
             "ERROR: {} ({}, line {} in file {})",
             $errno,
             $msg,
@@ -54,7 +54,7 @@ macro_rules! try_libc {
         if ret == -1 {
             let errno = unsafe { libc::errno() };
             // println will cause libc ocall and overwrite errno
-            println!(
+            error!(
                 "ERROR from libc: {} (line {} in file {})",
                 errno,
                 line!(),
diff --git a/src/libos/src/process/exit.rs b/src/libos/src/process/exit.rs
index 621473cc..ab99ba03 100644
--- a/src/libos/src/process/exit.rs
+++ b/src/libos/src/process/exit.rs
@@ -101,7 +101,7 @@ pub fn do_wait4(child_filter: &ChildProcessFilter, exit_status: &mut i32) -> Res
         waiter
     };
 
-    let child_pid = Waiter::sleep_until_woken_with_result(waiter);
+    let child_pid = waiter.sleep_until_woken_with_result();
 
     let mut current = current_ref.lock().unwrap();
     let child_i = {
diff --git a/src/libos/src/process/spawn/init_vm.rs b/src/libos/src/process/spawn/init_vm.rs
index 0a4d0442..246a870a 100644
--- a/src/libos/src/process/spawn/init_vm.rs
+++ b/src/libos/src/process/spawn/init_vm.rs
@@ -4,8 +4,8 @@ use std::ptr;
 use xmas_elf::{header, program, sections, ElfFile};
 
 pub const DEFAULT_STACK_SIZE: usize = 1 * 1024 * 1024;
-pub const DEFAULT_HEAP_SIZE: usize = 2 * 1024 * 1024;
-pub const DEFAULT_MMAP_SIZE: usize = 8 * 1024 * 1024;
+pub const DEFAULT_HEAP_SIZE: usize = 10 * 1024 * 1024;
+pub const DEFAULT_MMAP_SIZE: usize = 40 * 1024 * 1024;
 
 pub fn do_init(elf_file: &ElfFile, elf_buf: &[u8]) -> Result<ProcessVM, Error> {
     let mut code_seg = get_code_segment(elf_file)?;
diff --git a/src/libos/src/process/spawn/mod.rs b/src/libos/src/process/spawn/mod.rs
index fee26df7..d2bb6551 100644
--- a/src/libos/src/process/spawn/mod.rs
+++ b/src/libos/src/process/spawn/mod.rs
@@ -113,7 +113,8 @@ fn init_files(parent_ref: &ProcessRef, file_actions: &[FileAction]) -> Result<Fi
                     }
                 }
                 &FileAction::Close(fd) => {
-                    cloned_file_table.del(fd)?;
+                    // ignore error
+                    cloned_file_table.del(fd);
                 }
             }
         }
diff --git a/src/libos/src/process/wait.rs b/src/libos/src/process/wait.rs
index a753ee9d..23282195 100644
--- a/src/libos/src/process/wait.rs
+++ b/src/libos/src/process/wait.rs
@@ -48,14 +48,14 @@ where
         self.inner.lock().unwrap().data
     }
 
-    pub fn sleep_until_woken_with_result(waiter: Waiter<D, R>) -> R {
-        while !waiter.inner.lock().unwrap().is_woken {
+    pub fn sleep_until_woken_with_result(self) -> R {
+        while !self.inner.lock().unwrap().is_woken {
             unsafe {
-                wait_event(waiter.thread);
+                wait_event(self.thread);
             }
         }
 
-        waiter.inner.lock().unwrap().result.unwrap()
+        self.inner.lock().unwrap().result.unwrap()
     }
 }
 
diff --git a/src/libos/src/syscall/mod.rs b/src/libos/src/syscall/mod.rs
index 8587a145..42df50de 100644
--- a/src/libos/src/syscall/mod.rs
+++ b/src/libos/src/syscall/mod.rs
@@ -7,7 +7,7 @@
 //! 3. Dispatch the syscall to `do_*` (at this file)
 //! 4. Do some memory checks then call `mod::do_*` (at each module)
 
-use fs::{AccessFlags, AccessModes, FcntlCmd, File, FileDesc, FileRef, SocketFile, AT_FDCWD};
+use fs::*;
 use misc::{resource_t, rlimit_t, utsname_t};
 use prelude::*;
 use process::{pid_t, ChildProcessFilter, CloneFlags, FileAction, FutexFlags, FutexOp};
@@ -48,10 +48,15 @@ pub extern "C" fn dispatch_syscall(
     );
     #[cfg(feature = "syscall_timing")]
     let time_start = {
-        if crate::process::current_pid() == 1 && num == SYS_EXIT {
-            print_syscall_timing();
+        static mut LAST_PRINT: usize = 0;
+        let time = crate::time::do_gettimeofday().as_usec();
+        unsafe {
+            if time / 1000000 / 5 > LAST_PRINT {
+                LAST_PRINT = time / 1000000 / 5;
+                print_syscall_timing();
+            }
         }
-        crate::time::do_gettimeofday().as_usec()
+        time
     };
 
     let ret = match num {
@@ -248,6 +253,11 @@ pub extern "C" fn dispatch_syscall(
             arg3 as *mut c_void,
             arg4 as *mut libc::socklen_t,
         ),
+        SYS_GETPEERNAME => do_getpeername(
+            arg0 as c_int,
+            arg1 as *mut libc::sockaddr,
+            arg2 as *mut libc::socklen_t,
+        ),
         SYS_SENDTO => do_sendto(
             arg0 as c_int,
             arg1 as *const c_void,
@@ -295,6 +305,9 @@ fn print_syscall_timing() {
         }
         println!("{:>3}: {:>6} us", i, time);
     }
+    for x in unsafe { SYSCALL_TIMING.iter_mut() } {
+        *x = 0;
+    }
 }
 
 #[allow(non_camel_case_types)]
@@ -936,8 +949,16 @@ fn do_socket(domain: c_int, socket_type: c_int, protocol: c_int) -> Result<isize
         domain, socket_type, protocol
     );
 
-    let socket = SocketFile::new(domain, socket_type, protocol)?;
-    let file_ref: Arc<Box<File>> = Arc::new(Box::new(socket));
+    let file_ref: Arc<Box<File>> = match domain {
+//        libc::AF_LOCAL => {
+//            let unix_socket = UnixSocketFile::new(socket_type, protocol)?;
+//            Arc::new(Box::new(unix_socket))
+//        }
+        _ => {
+            let socket = SocketFile::new(domain, socket_type, protocol)?;
+            Arc::new(Box::new(socket))
+        }
+    };
 
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
@@ -958,10 +979,18 @@ fn do_connect(
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
     let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
-    let socket = file_ref.as_socket()?;
-
-    let ret = try_libc!(libc::ocall::connect(socket.fd(), addr, addr_len));
-    Ok(ret as isize)
+    if let Ok(socket) = file_ref.as_socket() {
+        let ret = try_libc!(libc::ocall::connect(socket.fd(), addr, addr_len));
+        Ok(ret as isize)
+    } else if let Ok(unix_socket) = file_ref.as_unix_socket() {
+        let addr = addr as *const libc::sockaddr_un;
+        check_ptr(addr)?; // TODO: check addr_len
+        let path = clone_cstring_safely(unsafe { (&*addr).sun_path.as_ptr() })?.to_string_lossy().into_owned();
+        unix_socket.connect(path)?;
+        Ok(0)
+    } else {
+        errno!(EBADF, "not a socket")
+    }
 }
 
 fn do_accept4(
@@ -977,13 +1006,26 @@ fn do_accept4(
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
     let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
-    let socket = file_ref.as_socket()?;
+    if let Ok(socket) = file_ref.as_socket() {
+        let socket = file_ref.as_socket()?;
 
-    let new_socket = socket.accept(addr, addr_len, flags)?;
-    let new_file_ref: Arc<Box<File>> = Arc::new(Box::new(new_socket));
-    let new_fd = proc.get_files().lock().unwrap().put(new_file_ref, false);
+        let new_socket = socket.accept(addr, addr_len, flags)?;
+        let new_file_ref: Arc<Box<File>> = Arc::new(Box::new(new_socket));
+        let new_fd = proc.get_files().lock().unwrap().put(new_file_ref, false);
 
-    Ok(new_fd as isize)
+        Ok(new_fd as isize)
+    } else if let Ok(unix_socket) = file_ref.as_unix_socket() {
+        let addr = addr as *mut libc::sockaddr_un;
+        check_mut_ptr(addr)?; // TODO: check addr_len
+
+        let new_socket = unix_socket.accept()?;
+        let new_file_ref: Arc<Box<File>> = Arc::new(Box::new(new_socket));
+        let new_fd = proc.get_files().lock().unwrap().put(new_file_ref, false);
+
+        Ok(0)
+    } else {
+        errno!(EBADF, "not a socket")
+    }
 }
 
 fn do_shutdown(fd: c_int, how: c_int) -> Result<isize, Error> {
@@ -991,10 +1033,12 @@ fn do_shutdown(fd: c_int, how: c_int) -> Result<isize, Error> {
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
     let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
-    let socket = file_ref.as_socket()?;
-
-    let ret = try_libc!(libc::ocall::shutdown(socket.fd(), how));
-    Ok(ret as isize)
+    if let Ok(socket) = file_ref.as_socket() {
+        let ret = try_libc!(libc::ocall::shutdown(socket.fd(), how));
+        Ok(ret as isize)
+    } else {
+        errno!(EBADF, "not a socket")
+    }
 }
 
 fn do_bind(
@@ -1006,10 +1050,19 @@ fn do_bind(
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
     let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
-    let socket = file_ref.as_socket()?;
-
-    let ret = try_libc!(libc::ocall::bind(socket.fd(), addr, addr_len));
-    Ok(ret as isize)
+    if let Ok(socket) = file_ref.as_socket() {
+        check_ptr(addr)?; // TODO: check addr_len
+        let ret = try_libc!(libc::ocall::bind(socket.fd(), addr, addr_len));
+        Ok(ret as isize)
+    } else if let Ok(unix_socket) = file_ref.as_unix_socket() {
+        let addr = addr as *const libc::sockaddr_un;
+        check_ptr(addr)?; // TODO: check addr_len
+        let path = clone_cstring_safely(unsafe { (&*addr).sun_path.as_ptr() })?.to_string_lossy().into_owned();
+        unix_socket.bind(path)?;
+        Ok(0)
+    } else {
+        errno!(EBADF, "not a socket")
+    }
 }
 
 fn do_listen(fd: c_int, backlog: c_int) -> Result<isize, Error> {
@@ -1017,10 +1070,15 @@ fn do_listen(fd: c_int, backlog: c_int) -> Result<isize, Error> {
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
     let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
-    let socket = file_ref.as_socket()?;
-
-    let ret = try_libc!(libc::ocall::listen(socket.fd(), backlog));
-    Ok(ret as isize)
+    if let Ok(socket) = file_ref.as_socket() {
+        let ret = try_libc!(libc::ocall::listen(socket.fd(), backlog));
+        Ok(ret as isize)
+    } else if let Ok(unix_socket) = file_ref.as_unix_socket() {
+        unix_socket.listen()?;
+        Ok(0)
+    } else {
+        errno!(EBADF, "not a socket")
+    }
 }
 
 fn do_setsockopt(
@@ -1037,16 +1095,21 @@ fn do_setsockopt(
     let current_ref = process::get_current();
     let mut proc = current_ref.lock().unwrap();
     let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
-    let socket = file_ref.as_socket()?;
-
-    let ret = try_libc!(libc::ocall::setsockopt(
-        socket.fd(),
-        level,
-        optname,
-        optval,
-        optlen
-    ));
-    Ok(ret as isize)
+    if let Ok(socket) = file_ref.as_socket() {
+        let ret = try_libc!(libc::ocall::setsockopt(
+            socket.fd(),
+            level,
+            optname,
+            optval,
+            optlen
+        ));
+        Ok(ret as isize)
+    } else if let Ok(unix_socket) = file_ref.as_unix_socket() {
+        warn!("setsockopt for unix socket is unimplemented");
+        Ok(0)
+    } else {
+        errno!(EBADF, "not a socket")
+    }
 }
 
 fn do_getsockopt(
@@ -1075,6 +1138,25 @@ fn do_getsockopt(
     Ok(ret as isize)
 }
 
+fn do_getpeername(
+    fd: c_int,
+    addr: *mut libc::sockaddr,
+    addr_len: *mut libc::socklen_t,
+) -> Result<isize, Error> {
+    info!("getpeername: fd: {}, addr: {:?}, addr_len: {:?}", fd, addr, addr_len);
+    let current_ref = process::get_current();
+    let mut proc = current_ref.lock().unwrap();
+    let file_ref = proc.get_files().lock().unwrap().get(fd as FileDesc)?;
+    let socket = file_ref.as_socket()?;
+
+    let ret = try_libc!(libc::ocall::getpeername(
+        socket.fd(),
+        addr,
+        addr_len
+    ));
+    Ok(ret as isize)
+}
+
 fn do_sendto(
     fd: c_int,
     base: *const c_void,
@@ -1230,18 +1312,6 @@ fn do_epoll_wait(
     Ok(count as isize)
 }
 
-pub trait AsSocket {
-    fn as_socket(&self) -> Result<&SocketFile, Error>;
-}
-
-impl AsSocket for FileRef {
-    fn as_socket(&self) -> Result<&SocketFile, Error> {
-        self.as_any()
-            .downcast_ref::<SocketFile>()
-            .ok_or(Error::new(Errno::EBADF, "not a socket"))
-    }
-}
-
 fn do_uname(name: *mut utsname_t) -> Result<isize, Error> {
     check_mut_ptr(name)?;
     let name = unsafe { &mut *name };
diff --git a/src/libos/src/vm/vm_space_prealloced.c b/src/libos/src/vm/vm_space_prealloced.c
index 62fba785..60f81a87 100644
--- a/src/libos/src/vm/vm_space_prealloced.c
+++ b/src/libos/src/vm/vm_space_prealloced.c
@@ -1,6 +1,6 @@
 #include <stddef.h>
 
-#define DATA_SPACE_SIZE (96*1024*1024)
+#define DATA_SPACE_SIZE (128*1024*1024)
 
 static char __prealloced_data_space[DATA_SPACE_SIZE]
     __attribute__ ((