install: fixes issue uutils#7795

Author: zcg00

src/uu/install/src/install.rs

@@ -1,7 +1,5 @@
 // This file is part of the uutils coreutils package.
-//
-// For the full copyright and license information, please view the LICENSE
-// file that was distributed with this source code.
+// For the full copyright and license information, please view the LICENSE file that was distributed with this source code.
 
 // spell-checker:ignore (ToDO) rwxr sourcepath targetpath Isnt uioerror
 
@@ -101,6 +99,9 @@ enum InstallError {
 
     #[error("cannot overwrite directory {} with non-directory {}", .0.quote(), .1.quote())]
     OverrideDirectoryFailed(PathBuf, PathBuf),
+
+    #[error("'{0}' and '{1}' are the same file")]
+    SameFile(PathBuf, PathBuf)
 }
 
 impl UError for InstallError {
@@ -751,6 +752,10 @@ fn copy_normal_file(from: &Path, to: &Path) -> UResult<()> {
 /// Returns an empty Result or an error in case of failure.
 ///
 fn copy_file(from: &Path, to: &Path) -> UResult<()> {
+    if from.canonicalize()? == to.canonicalize()? {
+        return Err(InstallError::SameFile(from.to_path_buf(), to.to_path_buf()).into());
+    }
+
     if to.is_dir() && !from.is_dir() {
         return Err(InstallError::OverrideDirectoryFailed(
             to.to_path_buf().clone(),