install: fixes issue #7795

src/uu/install/src/install.rs

@@ -101,6 +101,9 @@ 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 +754,12 @@ 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 let Ok(to_abs) = to.canonicalize() {
+        if from.canonicalize()? == to_abs {
+            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(),

tests/by-util/test_install.rs

@@ -1778,3 +1778,33 @@ fn test_install_failing_copy_file_to_target_contain_subdir_with_same_name() {
         .fails()
         .stderr_contains("cannot overwrite directory");
 }
+
+#[test]
+fn test_install_same_file() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let file = "file";
+
+    at.touch(file);
+    ucmd.arg(file)
+        .arg(".")
+        .fails()
+        .stderr_contains("'file' and './file' are the same file");
+}
+
+#[test]
+fn test_install_symlink_same_file() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let file = "file";
+    let target_dir = "target_dir";
+    let target_link = "target_link";
+
+    at.mkdir(target_dir);
+    at.touch(format!("{target_dir}/{file}"));
+    at.symlink_file(target_dir, target_link);
+    ucmd.arg(format!("{target_dir}/{file}"))
+        .arg(target_link)
+        .fails()
+        .stderr_contains(format!(
+            "'{target_dir}/{file}' and '{target_link}/{file}' are the same file"
+        ));
+}