Add as_path_string & as_path_buf convenience functions to Memfd

src/memfd.rs

@@ -1,7 +1,9 @@
 use crate::sealing;
 use rustix::fs::{MemfdFlags, SealFlags};
 use std::fs;
+use std::process;
 use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
+use std::path::{PathBuf};
 
 /// A `Memfd` builder, providing advanced options and flags for specifying its behavior.
 #[derive(Clone, Debug)]
@@ -159,6 +161,24 @@ impl Memfd {
         Self::try_from_fd(file)
     }
 
+    ///
+    /// Returns the absolute path to the `Memfd` file as a String.
+    /// The path contains the pid of the current process, so it can be shared with other processes.
+    /// The path remains valid until the `Memfd` or its `File` is dropped.
+    ///
+    pub fn as_path_string(&self) -> String {
+        format!("/proc/{}/fd/{}", process::id(), self.file.as_raw_fd())
+    }
+
+    ///
+    /// Returns the absolute path to the `Memfd` file as a PathBuf.
+    /// The path contains the pid of the current process, so it can be shared with other processes.
+    /// The path remains valid until the `Memfd` or its `File` is dropped.
+    ///
+    pub fn as_path_buf(&self) -> PathBuf {
+        PathBuf::from(self.as_path_string())
+    }
+
     /// Return a reference to the backing [`File`].
     ///
     /// [`File`]: fs::File

tests/memfd.rs

@@ -1,6 +1,9 @@
 extern crate memfd;
 use std::fs;
+use std::fs::File;
+use std::io::{Read, Seek, Write};
 use std::os::unix::io::AsRawFd;
+use memfd::Memfd;
 
 #[test]
 fn test_memfd_default() {
@@ -48,6 +51,40 @@ fn test_memfd_from_into() {
         .expect_err("unexpected conversion from a non-memfd file");
 }
 
+#[test]
+fn test_memfd_as_path_string() {
+    const TEST_CONTENT: &[u8] = b"test_memfd_as_path_string";
+    let m0 = create_memfd_with_content(TEST_CONTENT);
+    let path = m0.as_path_string();
+    let test_file = File::open(path).unwrap();
+    compare_file(test_file, TEST_CONTENT);
+}
+
+#[test]
+fn test_memfd_as_path_buf() {
+    const TEST_CONTENT: &[u8] = b"test_memfd_as_path_buf";
+    let m0 = create_memfd_with_content(TEST_CONTENT);
+    let path = m0.as_path_buf();
+    let test_file = File::open(path).unwrap();
+    compare_file(test_file, TEST_CONTENT);
+}
+
+fn create_memfd_with_content(content: &[u8]) -> Memfd {
+    let opts = memfd::MemfdOptions::default();
+    let m0 = opts.create("default").unwrap();
+    let mut file = m0.as_file();
+    file.write(content).unwrap();
+    file.seek(std::io::SeekFrom::Start(0)).unwrap();
+    return m0;
+}
+
+fn compare_file(mut file: File, expected_content: &[u8]) {
+    let mut content = Vec::new();
+    file.read_to_end(&mut content).unwrap();
+    assert_eq!(content.as_slice(), expected_content)
+}
+
+
 /// Check if the close-on-exec flag is set for the memfd.
 pub fn get_close_on_exec(memfd: &memfd::Memfd) -> std::io::Result<bool> {
     let flags = rustix::fs::fcntl_getfd(memfd.as_file())?;