From 27d1844952386a52f190935f8fde1cc967f1e01f Mon Sep 17 00:00:00 2001
From: Steve Lau <stevelauc@outlook.com>
Date: Sun, 11 Dec 2022 12:19:58 +0800
Subject: [PATCH] feat: I/O safety for 'sys/memfd' & 'sys/event' &
 'sys/eventfd'

---
 src/sys/epoll.rs   |  2 +-
 src/sys/event.rs   | 16 ++++++++--------
 src/sys/eventfd.rs |  6 +++---
 src/sys/memfd.rs   |  6 +++---
 4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/src/sys/epoll.rs b/src/sys/epoll.rs
index 9fdb1495bc..36f9c17d0e 100644
--- a/src/sys/epoll.rs
+++ b/src/sys/epoll.rs
@@ -83,7 +83,7 @@ impl EpollEvent {
 /// let epoll = Epoll::new(EpollCreateFlags::empty())?;
 ///
 /// // Create eventfd & Add event
-/// let eventfd = unsafe { OwnedFd::from_raw_fd(eventfd(0, EfdFlags::empty())?) };
+/// let eventfd = eventfd(0, EfdFlags::empty())?;
 /// epoll.add(&eventfd, EpollEvent::new(EpollFlags::EPOLLIN,DATA))?;
 ///
 /// // Arm eventfd & Time wait
diff --git a/src/sys/event.rs b/src/sys/event.rs
index d8ad628ea2..f21ba17324 100644
--- a/src/sys/event.rs
+++ b/src/sys/event.rs
@@ -8,7 +8,7 @@ use libc::{c_int, c_long, intptr_t, time_t, timespec, uintptr_t};
 use libc::{c_long, intptr_t, size_t, time_t, timespec, uintptr_t};
 use std::convert::TryInto;
 use std::mem;
-use std::os::unix::io::RawFd;
+use std::os::unix::io::{AsFd, AsRawFd, FromRawFd, OwnedFd};
 use std::ptr;
 
 // Redefine kevent in terms of programmer-friendly enums and bitfields.
@@ -207,10 +207,10 @@ libc_bitflags!(
     }
 );
 
-pub fn kqueue() -> Result<RawFd> {
+pub fn kqueue() -> Result<OwnedFd> {
     let res = unsafe { libc::kqueue() };
 
-    Errno::result(res)
+    Errno::result(res).map(|fd| unsafe { OwnedFd::from_raw_fd(fd) })
 }
 
 // KEvent can't derive Send because on some operating systems, udata is defined
@@ -267,8 +267,8 @@ impl KEvent {
     }
 }
 
-pub fn kevent(
-    kq: RawFd,
+pub fn kevent<Fd: AsFd>(
+    kq: Fd,
     changelist: &[KEvent],
     eventlist: &mut [KEvent],
     timeout_ms: usize,
@@ -293,15 +293,15 @@ type type_of_nchanges = c_int;
 #[cfg(target_os = "netbsd")]
 type type_of_nchanges = size_t;
 
-pub fn kevent_ts(
-    kq: RawFd,
+pub fn kevent_ts<Fd: AsFd>(
+    kq: Fd,
     changelist: &[KEvent],
     eventlist: &mut [KEvent],
     timeout_opt: Option<timespec>,
 ) -> Result<usize> {
     let res = unsafe {
         libc::kevent(
-            kq,
+            kq.as_fd().as_raw_fd(),
             changelist.as_ptr() as *const libc::kevent,
             changelist.len() as type_of_nchanges,
             eventlist.as_mut_ptr() as *mut libc::kevent,
diff --git a/src/sys/eventfd.rs b/src/sys/eventfd.rs
index cd906720cd..f1723519cf 100644
--- a/src/sys/eventfd.rs
+++ b/src/sys/eventfd.rs
@@ -1,6 +1,6 @@
 use crate::errno::Errno;
 use crate::Result;
-use std::os::unix::io::RawFd;
+use std::os::unix::io::{FromRawFd, OwnedFd};
 
 libc_bitflags! {
     pub struct EfdFlags: libc::c_int {
@@ -10,8 +10,8 @@ libc_bitflags! {
     }
 }
 
-pub fn eventfd(initval: libc::c_uint, flags: EfdFlags) -> Result<RawFd> {
+pub fn eventfd(initval: libc::c_uint, flags: EfdFlags) -> Result<OwnedFd> {
     let res = unsafe { libc::eventfd(initval, flags.bits()) };
 
-    Errno::result(res).map(|r| r as RawFd)
+    Errno::result(res).map(|r| unsafe { OwnedFd::from_raw_fd(r) })
 }
diff --git a/src/sys/memfd.rs b/src/sys/memfd.rs
index ad9345e89d..f349a743ed 100644
--- a/src/sys/memfd.rs
+++ b/src/sys/memfd.rs
@@ -1,7 +1,7 @@
 //! Interfaces for managing memory-backed files.
 
 use cfg_if::cfg_if;
-use std::os::unix::io::RawFd;
+use std::os::unix::io::{FromRawFd, OwnedFd, RawFd};
 
 use crate::errno::Errno;
 use crate::Result;
@@ -40,7 +40,7 @@ libc_bitflags!(
 /// For more information, see [`memfd_create(2)`].
 ///
 /// [`memfd_create(2)`]: https://man7.org/linux/man-pages/man2/memfd_create.2.html
-pub fn memfd_create(name: &CStr, flags: MemFdCreateFlag) -> Result<RawFd> {
+pub fn memfd_create(name: &CStr, flags: MemFdCreateFlag) -> Result<OwnedFd> {
     let res = unsafe {
         cfg_if! {
             if #[cfg(all(
@@ -60,5 +60,5 @@ pub fn memfd_create(name: &CStr, flags: MemFdCreateFlag) -> Result<RawFd> {
         }
     };
 
-    Errno::result(res).map(|r| r as RawFd)
+    Errno::result(res).map(|r| unsafe { OwnedFd::from_raw_fd(r as RawFd) })
 }