refactor: change name arg of memfd_create() to &NixPath

changelog/2431.changed.md

@@ -0,0 +1 @@
+Change the type of the `name` argument of `memfd_create()` from `&CStr` to `<P: NixPath>(name: &P)`

src/sys/memfd.rs

@@ -4,8 +4,7 @@ use cfg_if::cfg_if;
 use std::os::unix::io::{FromRawFd, OwnedFd, RawFd};
 
 use crate::errno::Errno;
-use crate::Result;
-use std::ffi::CStr;
+use crate::{NixPath, Result};
 
 libc_bitflags!(
     /// Options that change the behavior of [`memfd_create`].
@@ -84,9 +83,13 @@ libc_bitflags!(
 ///
 /// [`memfd_create(2)`]: https://man7.org/linux/man-pages/man2/memfd_create.2.html
 #[inline] // Delays codegen, preventing linker errors with dylibs and --no-allow-shlib-undefined
-pub fn memfd_create(name: &CStr, flags: MemFdCreateFlag) -> Result<OwnedFd> {
-    let res = unsafe {
-        cfg_if! {
+pub fn memfd_create<P: NixPath + ?Sized>(
+    name: &P,
+    flags: MemFdCreateFlag,
+) -> Result<OwnedFd> {
+    let res = name.with_nix_path(|cstr| {
+        unsafe {
+            cfg_if! {
             if #[cfg(all(
                 // Android does not have a memfd_create symbol
                 not(target_os = "android"),
@@ -97,12 +100,13 @@ pub fn memfd_create(name: &CStr, flags: MemFdCreateFlag) -> Result<OwnedFd> {
                     target_env = "musl",
                 )))]
             {
-                libc::memfd_create(name.as_ptr(), flags.bits())
+                libc::memfd_create(cstr.as_ptr(), flags.bits())
             } else {
-                libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags.bits())
+                libc::syscall(libc::SYS_memfd_create, cstr.as_ptr(), flags.bits())
             }
         }
-    };
+        }
+    })?;
 
     Errno::result(res).map(|r| unsafe { OwnedFd::from_raw_fd(r as RawFd) })
 }

test/sys/mod.rs

@@ -82,3 +82,6 @@ mod test_statfs;
     target_os = "haiku"
 )))]
 mod test_resource;
+
+#[cfg(any(linux_android, target_os = "freebsd"))]
+mod test_memfd;

test/sys/test_memfd.rs

@@ -0,0 +1,22 @@
+use nix::sys::memfd::memfd_create;
+use nix::sys::memfd::MemFdCreateFlag;
+use nix::unistd::lseek;
+use nix::unistd::read;
+use nix::unistd::{write, Whence};
+use std::os::fd::{AsFd, AsRawFd};
+
+#[test]
+fn test_memfd_create() {
+    let fd =
+        memfd_create("test_memfd_create_name", MemFdCreateFlag::MFD_CLOEXEC)
+            .unwrap();
+    let contents = b"hello";
+    assert_eq!(write(fd.as_fd(), contents).unwrap(), 5);
+
+    lseek(fd.as_raw_fd(), 0, Whence::SeekSet).unwrap();
+
+    let mut buf = vec![0_u8; contents.len()];
+    assert_eq!(read(fd.as_raw_fd(), &mut buf).unwrap(), 5);
+
+    assert_eq!(contents, buf.as_slice());
+}