refactor: I/O safety for sys/fanotify.rs (#2443)

* refactor: I/O safety for sys/fanotify.rs

* chore: correct changelog entry pr number

Author: SteveLauC

changelog/2443.changed.md

@@ -0,0 +1 @@
+Module sys/fanotify now adopts I/O safety

src/fcntl.rs

@@ -231,12 +231,6 @@ libc_bitflags!(
     }
 );
 
-/// Computes the raw fd consumed by a function of the form `*at`.
-#[cfg(all(feature = "fanotify", target_os = "linux"))]
-pub(crate) fn at_rawfd(fd: Option<RawFd>) -> RawFd {
-    fd.unwrap_or(libc::AT_FDCWD)
-}
-
 feature! {
 #![feature = "fs"]
 

src/sys/fanotify.rs

@@ -11,7 +11,7 @@
 //! [fanotify(7)](https://man7.org/linux/man-pages/man7/fanotify.7.html).
 
 use crate::errno::Errno;
-use crate::fcntl::{at_rawfd, OFlag};
+use crate::fcntl::OFlag;
 use crate::unistd::{close, read, write};
 use crate::{NixPath, Result};
 use std::marker::PhantomData;
@@ -321,24 +321,23 @@ impl Fanotify {
     }
 
     /// Add, remove, or modify an fanotify mark on a filesystem object.
-    /// If `dirfd` is `None`, `AT_FDCWD` is used.
     ///
     /// Returns a Result containing either `()` on success or errno otherwise.
     ///
     /// For more information, see [fanotify_mark(2)](https://man7.org/linux/man-pages/man7/fanotify_mark.2.html).
-    pub fn mark<P: ?Sized + NixPath>(
+    pub fn mark<Fd: std::os::fd::AsFd, P: ?Sized + NixPath>(
         &self,
         flags: MarkFlags,
         mask: MaskFlags,
-        dirfd: Option<RawFd>,
+        dirfd: Fd,
         path: Option<&P>,
     ) -> Result<()> {
         let res = crate::with_opt_nix_path(path, |p| unsafe {
             libc::fanotify_mark(
                 self.fd.as_raw_fd(),
                 flags.bits(),
                 mask.bits(),
-                at_rawfd(dirfd),
+                dirfd.as_fd().as_raw_fd(),
                 p,
             )
         })?;

test/sys/test_fanotify.rs

@@ -1,5 +1,6 @@
 use crate::*;
 use nix::errno::Errno;
+use nix::fcntl::AT_FDCWD;
 use nix::sys::fanotify::{
     EventFFlags, Fanotify, FanotifyResponse, InitFlags, MarkFlags, MaskFlags,
     Response,
@@ -36,7 +37,7 @@ fn test_fanotify_notifications() {
         .mark(
             MarkFlags::FAN_MARK_ADD,
             MaskFlags::FAN_OPEN | MaskFlags::FAN_MODIFY | MaskFlags::FAN_CLOSE,
-            None,
+            AT_FDCWD,
             Some(&tempfile),
         )
         .unwrap();
@@ -99,7 +100,7 @@ fn test_fanotify_responses() {
         .mark(
             MarkFlags::FAN_MARK_ADD,
             MaskFlags::FAN_OPEN_PERM,
-            None,
+            AT_FDCWD,
             Some(&tempfile),
         )
         .unwrap();
@@ -182,7 +183,7 @@ fn test_fanotify_overflow() {
         .mark(
             MarkFlags::FAN_MARK_ADD,
             MaskFlags::FAN_OPEN,
-            None,
+            AT_FDCWD,
             Some(&tempfile),
         )
         .unwrap();