diff --git a/src/libos/src/fs/file_ops/access.rs b/src/libos/src/fs/file_ops/access.rs
index 19f38c0f..f71e6ba7 100644
--- a/src/libos/src/fs/file_ops/access.rs
+++ b/src/libos/src/fs/file_ops/access.rs
@@ -46,9 +46,11 @@ pub fn do_faccessat(
 
 pub fn do_access(path: &str, mode: AccessibilityCheckMode) -> Result<()> {
     debug!("access: path: {:?}, mode: {:?}", path, mode);
-    let current_ref = process::get_current();
-    let mut current = current_ref.lock().unwrap();
-    let inode = current.lookup_inode(path)?;
+    let inode = {
+        let current_ref = process::get_current();
+        let mut current = current_ref.lock().unwrap();
+        current.lookup_inode(path)?
+    };
     //let metadata = inode.get_metadata();
     // TODO: check metadata.mode with mode
     Ok(())
diff --git a/src/libos/src/fs/file_ops/chdir.rs b/src/libos/src/fs/file_ops/chdir.rs
index f0ef7d89..6d7ed245 100644
--- a/src/libos/src/fs/file_ops/chdir.rs
+++ b/src/libos/src/fs/file_ops/chdir.rs
@@ -1,15 +1,17 @@
 use super::*;
 
 pub fn do_chdir(path: &str) -> Result<()> {
+    debug!("chdir: path: {:?}", path);
+
     let current_ref = process::get_current();
     let mut current_process = current_ref.lock().unwrap();
-    debug!("chdir: path: {:?}", path);
 
     let inode = current_process.lookup_inode(path)?;
     let info = inode.metadata()?;
     if info.type_ != FileType::Dir {
         return_errno!(ENOTDIR, "");
     }
+
     current_process.change_cwd(path);
     Ok(())
 }
diff --git a/src/libos/src/fs/file_ops/dirent.rs b/src/libos/src/fs/file_ops/dirent.rs
index c4d6bd90..192112ed 100644
--- a/src/libos/src/fs/file_ops/dirent.rs
+++ b/src/libos/src/fs/file_ops/dirent.rs
@@ -67,9 +67,7 @@ pub fn do_getdents64(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
         buf.as_ptr(),
         buf.len()
     );
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     let info = file_ref.metadata()?;
     if info.type_ != FileType::Dir {
         return_errno!(ENOTDIR, "");
diff --git a/src/libos/src/fs/file_ops/dirfd.rs b/src/libos/src/fs/file_ops/dirfd.rs
index 4ad21360..129f69f2 100644
--- a/src/libos/src/fs/file_ops/dirfd.rs
+++ b/src/libos/src/fs/file_ops/dirfd.rs
@@ -24,9 +24,7 @@ impl DirFd {
 // Get the absolute path of directory
 pub fn get_dir_path(dirfd: FileDesc) -> Result<String> {
     let dir_path = {
-        let current_ref = process::get_current();
-        let proc = current_ref.lock().unwrap();
-        let file_ref = proc.get_files().lock().unwrap().get(dirfd)?;
+        let file_ref = process::get_file(dirfd)?;
         if let Ok(inode_file) = file_ref.as_inode_file() {
             if inode_file.metadata()?.type_ != FileType::Dir {
                 return_errno!(ENOTDIR, "not a directory");
diff --git a/src/libos/src/fs/file_ops/fsync.rs b/src/libos/src/fs/file_ops/fsync.rs
index b6fa58f4..357b3aad 100644
--- a/src/libos/src/fs/file_ops/fsync.rs
+++ b/src/libos/src/fs/file_ops/fsync.rs
@@ -2,18 +2,14 @@ use super::*;
 
 pub fn do_fsync(fd: FileDesc) -> Result<()> {
     debug!("fsync: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.sync_all()?;
     Ok(())
 }
 
 pub fn do_fdatasync(fd: FileDesc) -> Result<()> {
     debug!("fdatasync: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.sync_data()?;
     Ok(())
 }
diff --git a/src/libos/src/fs/file_ops/ioctl/mod.rs b/src/libos/src/fs/file_ops/ioctl/mod.rs
index 98e4a39f..379ea888 100644
--- a/src/libos/src/fs/file_ops/ioctl/mod.rs
+++ b/src/libos/src/fs/file_ops/ioctl/mod.rs
@@ -66,8 +66,6 @@ impl<'a> IoctlCmd<'a> {
 
 pub fn do_ioctl(fd: FileDesc, cmd: &mut IoctlCmd) -> Result<()> {
     debug!("ioctl: fd: {}, cmd: {:?}", fd, cmd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.ioctl(cmd)
 }
diff --git a/src/libos/src/fs/file_ops/link.rs b/src/libos/src/fs/file_ops/link.rs
index 3b6c8a5e..f59d629a 100644
--- a/src/libos/src/fs/file_ops/link.rs
+++ b/src/libos/src/fs/file_ops/link.rs
@@ -1,13 +1,16 @@
 use super::*;
 
 pub fn do_link(oldpath: &str, newpath: &str) -> Result<()> {
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
     debug!("link: oldpath: {:?}, newpath: {:?}", oldpath, newpath);
 
     let (new_dir_path, new_file_name) = split_path(&newpath);
-    let inode = current_process.lookup_inode(&oldpath)?;
-    let new_dir_inode = current_process.lookup_inode(new_dir_path)?;
+    let (inode, new_dir_inode) = {
+        let current_ref = process::get_current();
+        let current_process = current_ref.lock().unwrap();
+        let inode = current_process.lookup_inode(&oldpath)?;
+        let new_dir_inode = current_process.lookup_inode(new_dir_path)?;
+        (inode, new_dir_inode)
+    };
     new_dir_inode.link(new_file_name, &inode)?;
     Ok(())
 }
diff --git a/src/libos/src/fs/file_ops/lseek.rs b/src/libos/src/fs/file_ops/lseek.rs
index c8882ae5..24dbc63b 100644
--- a/src/libos/src/fs/file_ops/lseek.rs
+++ b/src/libos/src/fs/file_ops/lseek.rs
@@ -1,8 +1,6 @@
 use super::*;
 
 pub fn do_lseek(fd: FileDesc, offset: SeekFrom) -> Result<off_t> {
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.seek(offset)
 }
diff --git a/src/libos/src/fs/file_ops/mkdir.rs b/src/libos/src/fs/file_ops/mkdir.rs
index 12ba8076..e8059ff1 100644
--- a/src/libos/src/fs/file_ops/mkdir.rs
+++ b/src/libos/src/fs/file_ops/mkdir.rs
@@ -1,13 +1,15 @@
 use super::*;
 
 pub fn do_mkdir(path: &str, mode: usize) -> Result<()> {
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
     // TODO: check pathname
     debug!("mkdir: path: {:?}, mode: {:#o}", path, mode);
 
     let (dir_path, file_name) = split_path(&path);
-    let inode = current_process.lookup_inode(dir_path)?;
+    let inode = {
+        let current_ref = process::get_current();
+        let current_process = current_ref.lock().unwrap();
+        current_process.lookup_inode(dir_path)?
+    };
     if inode.find(file_name).is_ok() {
         return_errno!(EEXIST, "");
     }
diff --git a/src/libos/src/fs/file_ops/read.rs b/src/libos/src/fs/file_ops/read.rs
index b93a7401..13d0ec83 100644
--- a/src/libos/src/fs/file_ops/read.rs
+++ b/src/libos/src/fs/file_ops/read.rs
@@ -2,24 +2,18 @@ use super::*;
 
 pub fn do_read(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
     debug!("read: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.read(buf)
 }
 
 pub fn do_readv(fd: FileDesc, bufs: &mut [&mut [u8]]) -> Result<usize> {
     debug!("readv: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.readv(bufs)
 }
 
 pub fn do_pread(fd: FileDesc, buf: &mut [u8], offset: usize) -> Result<usize> {
     debug!("pread: fd: {}, offset: {}", fd, offset);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.read_at(offset, buf)
 }
diff --git a/src/libos/src/fs/file_ops/rmdir.rs b/src/libos/src/fs/file_ops/rmdir.rs
index 6f35fb37..812f0123 100644
--- a/src/libos/src/fs/file_ops/rmdir.rs
+++ b/src/libos/src/fs/file_ops/rmdir.rs
@@ -1,12 +1,14 @@
 use super::*;
 
 pub fn do_rmdir(path: &str) -> Result<()> {
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
     debug!("rmdir: path: {:?}", path);
 
     let (dir_path, file_name) = split_path(&path);
-    let dir_inode = current_process.lookup_inode(dir_path)?;
+    let dir_inode = {
+        let current_ref = process::get_current();
+        let current_process = current_ref.lock().unwrap();
+        current_process.lookup_inode(dir_path)?
+    };
     let file_inode = dir_inode.find(file_name)?;
     if file_inode.metadata()?.type_ != FileType::Dir {
         return_errno!(ENOTDIR, "rmdir on not directory");
diff --git a/src/libos/src/fs/file_ops/stat.rs b/src/libos/src/fs/file_ops/stat.rs
index 280912dd..758db741 100644
--- a/src/libos/src/fs/file_ops/stat.rs
+++ b/src/libos/src/fs/file_ops/stat.rs
@@ -141,9 +141,7 @@ fn do_stat(path: &str) -> Result<Stat> {
 
 pub fn do_fstat(fd: u32) -> Result<Stat> {
     debug!("fstat: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd as FileDesc)?;
     let stat = Stat::from(file_ref.metadata()?);
     // TODO: handle symlink
     Ok(stat)
@@ -151,9 +149,11 @@ pub fn do_fstat(fd: u32) -> Result<Stat> {
 
 pub fn do_lstat(path: &str) -> Result<Stat> {
     debug!("lstat: path: {}", path);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let inode = current_process.lookup_inode(&path)?;
+    let inode = {
+        let current_ref = process::get_current();
+        let current_process = current_ref.lock().unwrap();
+        current_process.lookup_inode(&path)?
+    };
     let stat = Stat::from(inode.metadata()?);
     Ok(stat)
 }
diff --git a/src/libos/src/fs/file_ops/symlink.rs b/src/libos/src/fs/file_ops/symlink.rs
index b83ee848..8257dd48 100644
--- a/src/libos/src/fs/file_ops/symlink.rs
+++ b/src/libos/src/fs/file_ops/symlink.rs
@@ -12,9 +12,7 @@ pub fn do_readlink(path: &str, buf: &mut [u8]) -> Result<usize> {
                 .trim_start_matches("/proc/self/fd/")
                 .parse::<FileDesc>()
                 .map_err(|e| errno!(EBADF, "Invalid file descriptor"))?;
-            let current_ref = process::get_current();
-            let current = current_ref.lock().unwrap();
-            let file_ref = current.get_files().lock().unwrap().get(fd)?;
+            let file_ref = process::get_file(fd)?;
             if let Ok(inode_file) = file_ref.as_inode_file() {
                 inode_file.get_abs_path().to_owned()
             } else {
diff --git a/src/libos/src/fs/file_ops/truncate.rs b/src/libos/src/fs/file_ops/truncate.rs
index f287761b..435b7a47 100644
--- a/src/libos/src/fs/file_ops/truncate.rs
+++ b/src/libos/src/fs/file_ops/truncate.rs
@@ -2,17 +2,18 @@ use super::*;
 
 pub fn do_truncate(path: &str, len: usize) -> Result<()> {
     debug!("truncate: path: {:?}, len: {}", path, len);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    current_process.lookup_inode(&path)?.resize(len)?;
+    let inode = {
+        let current_ref = process::get_current();
+        let current_process = current_ref.lock().unwrap();
+        current_process.lookup_inode(&path)?
+    };
+    inode.resize(len)?;
     Ok(())
 }
 
 pub fn do_ftruncate(fd: FileDesc, len: usize) -> Result<()> {
     debug!("ftruncate: fd: {}, len: {}", fd, len);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.set_len(len as u64)?;
     Ok(())
 }
diff --git a/src/libos/src/fs/file_ops/unlink.rs b/src/libos/src/fs/file_ops/unlink.rs
index 8143fd2f..dd74ba84 100644
--- a/src/libos/src/fs/file_ops/unlink.rs
+++ b/src/libos/src/fs/file_ops/unlink.rs
@@ -1,12 +1,14 @@
 use super::*;
 
 pub fn do_unlink(path: &str) -> Result<()> {
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
     debug!("unlink: path: {:?}", path);
 
     let (dir_path, file_name) = split_path(&path);
-    let dir_inode = current_process.lookup_inode(dir_path)?;
+    let dir_inode = {
+        let current_ref = process::get_current();
+        let current_process = current_ref.lock().unwrap();
+        current_process.lookup_inode(dir_path)?
+    };
     let file_inode = dir_inode.find(file_name)?;
     if file_inode.metadata()?.type_ == FileType::Dir {
         return_errno!(EISDIR, "unlink on directory");
diff --git a/src/libos/src/fs/file_ops/write.rs b/src/libos/src/fs/file_ops/write.rs
index 3e49e267..613a954f 100644
--- a/src/libos/src/fs/file_ops/write.rs
+++ b/src/libos/src/fs/file_ops/write.rs
@@ -2,24 +2,18 @@ use super::*;
 
 pub fn do_write(fd: FileDesc, buf: &[u8]) -> Result<usize> {
     debug!("write: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.write(buf)
 }
 
 pub fn do_writev(fd: FileDesc, bufs: &[&[u8]]) -> Result<usize> {
     debug!("writev: fd: {}", fd);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.writev(bufs)
 }
 
 pub fn do_pwrite(fd: FileDesc, buf: &[u8], offset: usize) -> Result<usize> {
     debug!("pwrite: fd: {}, offset: {}", fd, offset);
-    let current_ref = process::get_current();
-    let current_process = current_ref.lock().unwrap();
-    let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+    let file_ref = process::get_file(fd)?;
     file_ref.write_at(offset, buf)
 }
diff --git a/src/libos/src/fs/syscalls.rs b/src/libos/src/fs/syscalls.rs
index a6837369..0b416b53 100644
--- a/src/libos/src/fs/syscalls.rs
+++ b/src/libos/src/fs/syscalls.rs
@@ -27,13 +27,10 @@ pub fn do_eventfd2(init_val: u32, flags: i32) -> Result<isize> {
         Arc::new(Box::new(event))
     };
 
-    let current_ref = process::get_current();
-    let mut proc = current_ref.lock().unwrap();
-
-    let fd = proc.get_files().lock().unwrap().put(
+    let fd = process::put_file(
         file_ref,
         inner_flags.contains(EventCreationFlags::EFD_CLOEXEC),
-    );
+    )?;
     Ok(fd as isize)
 }
 
diff --git a/src/libos/src/net/syscalls.rs b/src/libos/src/net/syscalls.rs
index 80258ad5..e48ce063 100644
--- a/src/libos/src/net/syscalls.rs
+++ b/src/libos/src/net/syscalls.rs
@@ -10,10 +10,8 @@ pub fn do_sendmsg(fd: c_int, msg_ptr: *const msghdr, flags_c: c_int) -> Result<i
         "sendmsg: fd: {}, msg: {:?}, flags: 0x{:x}",
         fd, msg_ptr, flags_c
     );
-    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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let msg_c = {
             from_user::check_ptr(msg_ptr)?;
@@ -40,10 +38,8 @@ pub fn do_recvmsg(fd: c_int, msg_mut_ptr: *mut msghdr_mut, flags_c: c_int) -> Re
         "recvmsg: fd: {}, msg: {:?}, flags: 0x{:x}",
         fd, msg_mut_ptr, flags_c
     );
-    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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let msg_mut_c = {
             from_user::check_mut_ptr(msg_mut_ptr)?;
diff --git a/src/libos/src/process/mod.rs b/src/libos/src/process/mod.rs
index 0783148b..5e7145d5 100644
--- a/src/libos/src/process/mod.rs
+++ b/src/libos/src/process/mod.rs
@@ -82,8 +82,28 @@ mod task;
 mod thread;
 mod wait;
 
+/// Get a file from the file table of the current process
+pub fn get_file(fd: FileDesc) -> Result<FileRef> {
+    let current_ref = get_current();
+    let current = current_ref.lock().unwrap();
+    let file_ref = current.get_files().lock().unwrap().get(fd as FileDesc)?;
+    Ok(file_ref)
+}
+
+/// Put a file into the file table of the current process
+pub fn put_file(new_file: FileRef, close_on_spawn: bool) -> Result<FileDesc> {
+    let current_ref = get_current();
+    let current = current_ref.lock().unwrap();
+    let new_fd = current
+        .get_files()
+        .lock()
+        .unwrap()
+        .put(new_file, close_on_spawn);
+    Ok(new_fd)
+}
+
 use super::*;
-use fs::{File, FileRef, FileTable};
+use fs::{File, FileDesc, FileRef, FileTable};
 use misc::ResourceLimitsRef;
 use time::GLOBAL_PROFILER;
 use vm::ProcessVM;
diff --git a/src/libos/src/syscall/mod.rs b/src/libos/src/syscall/mod.rs
index 17544c29..de282409 100644
--- a/src/libos/src/syscall/mod.rs
+++ b/src/libos/src/syscall/mod.rs
@@ -1044,10 +1044,7 @@ fn do_socket(domain: c_int, socket_type: c_int, protocol: c_int) -> Result<isize
         }
     };
 
-    let current_ref = process::get_current();
-    let mut proc = current_ref.lock().unwrap();
-
-    let fd = proc.get_files().lock().unwrap().put(file_ref, false);
+    let fd = process::put_file(file_ref, false)?;
     Ok(fd as isize)
 }
 
@@ -1056,9 +1053,7 @@ fn do_connect(fd: c_int, addr: *const libc::sockaddr, addr_len: libc::socklen_t)
         "connect: 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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let ret = try_libc!(libc::ocall::connect(socket.fd(), addr, addr_len));
         Ok(ret as isize)
@@ -1093,15 +1088,13 @@ fn do_accept4(
         "accept4: fd: {}, addr: {:?}, addr_len: {:?}, flags: {:#x}",
         fd, addr, addr_len, flags
     );
-    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 file_ref = process::get_file(fd as FileDesc)?;
     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<dyn File>> = Arc::new(Box::new(new_socket));
-        let new_fd = proc.get_files().lock().unwrap().put(new_file_ref, false);
+        let new_fd = process::put_file(new_file_ref, false)?;
 
         Ok(new_fd as isize)
     } else if let Ok(unix_socket) = file_ref.as_unix_socket() {
@@ -1110,7 +1103,7 @@ fn do_accept4(
 
         let new_socket = unix_socket.accept()?;
         let new_file_ref: Arc<Box<dyn File>> = Arc::new(Box::new(new_socket));
-        let new_fd = proc.get_files().lock().unwrap().put(new_file_ref, false);
+        let new_fd = process::put_file(new_file_ref, false)?;
 
         Ok(new_fd as isize)
     } else {
@@ -1120,9 +1113,7 @@ fn do_accept4(
 
 fn do_shutdown(fd: c_int, how: c_int) -> Result<isize> {
     debug!("shutdown: fd: {}, how: {}", fd, how);
-    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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let ret = try_libc!(libc::ocall::shutdown(socket.fd(), how));
         Ok(ret as isize)
@@ -1133,9 +1124,7 @@ fn do_shutdown(fd: c_int, how: c_int) -> Result<isize> {
 
 fn do_bind(fd: c_int, addr: *const libc::sockaddr, addr_len: libc::socklen_t) -> Result<isize> {
     debug!("bind: 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 file_ref = process::get_file(fd as FileDesc)?;
     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));
@@ -1155,9 +1144,7 @@ fn do_bind(fd: c_int, addr: *const libc::sockaddr, addr_len: libc::socklen_t) ->
 
 fn do_listen(fd: c_int, backlog: c_int) -> Result<isize> {
     debug!("listen: fd: {}, backlog: {}", fd, backlog);
-    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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let ret = try_libc!(libc::ocall::listen(socket.fd(), backlog));
         Ok(ret as isize)
@@ -1180,9 +1167,7 @@ fn do_setsockopt(
         "setsockopt: fd: {}, level: {}, optname: {}, optval: {:?}, optlen: {:?}",
         fd, level, optname, optval, optlen
     );
-    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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let ret = try_libc!(libc::ocall::setsockopt(
             socket.fd(),
@@ -1211,9 +1196,7 @@ fn do_getsockopt(
         "getsockopt: fd: {}, level: {}, optname: {}, optval: {:?}, optlen: {:?}",
         fd, level, optname, optval, optlen
     );
-    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 file_ref = process::get_file(fd as FileDesc)?;
     let socket = file_ref.as_socket()?;
 
     let ret = try_libc!(libc::ocall::getsockopt(
@@ -1235,9 +1218,7 @@ fn do_getpeername(
         "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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let ret = try_libc!(libc::ocall::getpeername(socket.fd(), addr, addr_len));
         Ok(ret as isize)
@@ -1261,9 +1242,7 @@ fn do_getsockname(
         "getsockname: 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 file_ref = process::get_file(fd as FileDesc)?;
     if let Ok(socket) = file_ref.as_socket() {
         let ret = try_libc!(libc::ocall::getsockname(socket.fd(), addr, addr_len));
         Ok(ret as isize)
@@ -1287,9 +1266,7 @@ fn do_sendto(
         "sendto: fd: {}, base: {:?}, len: {}, addr: {:?}, addr_len: {}",
         fd, base, len, 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 file_ref = process::get_file(fd as FileDesc)?;
     let socket = file_ref.as_socket()?;
 
     let ret = try_libc!(libc::ocall::sendto(
@@ -1315,9 +1292,7 @@ fn do_recvfrom(
         "recvfrom: fd: {}, base: {:?}, len: {}, flags: {}, addr: {:?}, addr_len: {:?}",
         fd, base, len, flags, 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 file_ref = process::get_file(fd as FileDesc)?;
     let socket = file_ref.as_socket()?;
 
     let ret = try_libc!(libc::ocall::recvfrom(
diff --git a/src/libos/src/vm/process_vm.rs b/src/libos/src/vm/process_vm.rs
index a1f7cbec..4f3f2c52 100644
--- a/src/libos/src/vm/process_vm.rs
+++ b/src/libos/src/vm/process_vm.rs
@@ -301,9 +301,7 @@ impl ProcessVM {
             if flags.contains(MMapFlags::MAP_ANONYMOUS) {
                 VMInitializer::FillZeros()
             } else {
-                let current_ref = get_current();
-                let current_process = current_ref.lock().unwrap();
-                let file_ref = current_process.get_files().lock().unwrap().get(fd)?;
+                let file_ref = process::get_file(fd)?;
                 VMInitializer::LoadFromFile {
                     file: file_ref,
                     offset: offset,