rust: Bind lcfs_fd_measure_fsverity

This is a reasonable thing to want to do.

Signed-off-by: Colin Walters <[email protected]>

rust/composefs-sys/Cargo.toml

@@ -19,8 +19,9 @@ name = "composefs"
 version = "1"
 
 [features]
-# Depend on 1.0.4 APIs
+# Require functions from the C library corresponding to the provided version.
 v1_0_4 = []
+v1_0_7 = ["v1_0_4"]
 
 [build-dependencies]
 system-deps = "6"

rust/composefs-sys/src/lib.rs

@@ -11,6 +11,8 @@ extern "C" {
     pub fn lcfs_fd_get_fsverity(digest: *mut u8, fd: std::os::raw::c_int) -> std::os::raw::c_int;
     #[cfg(feature = "v1_0_4")]
     pub fn lcfs_fd_enable_fsverity(fd: std::os::raw::c_int) -> std::os::raw::c_int;
+    #[cfg(feature = "v1_0_7")]
+    pub fn lcfs_fd_measure_fsverity(digest: *mut u8, fd: std::os::raw::c_int) -> std::os::raw::c_int;
 }
 
 /// Convert an integer return value into a `Result`.
@@ -41,6 +43,19 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    #[cfg(feature = "v1_0_7")]
+    fn test_fd_measure_fsverity() -> Result<()> {
+        let mut tf = tempfile::NamedTempFile::new()?;
+        tf.write_all(b"hello")?;
+        let tf = std::fs::File::open(tf.path())?;
+        // This fd can't have fsverity enabled
+        let mut buf = [0u8; LCFS_SHA256_DIGEST_LEN];
+        let r = unsafe { lcfs_fd_measure_fsverity(buf.as_mut_ptr(), tf.as_raw_fd()) };
+        assert_ne!(r, 0);
+        Ok(())
+    }
+
     #[test]
     fn test_digest() -> Result<()> {
         for f in [lcfs_compute_fsverity_from_fd, lcfs_fd_get_fsverity] {