Preserve Unix permissions on extracted files

src/fs.rs

@@ -53,6 +53,15 @@ pub fn metadata<P: AsRef<Path>>(path: P) -> Result<fs::Metadata> {
     fs::metadata(path).map_err(|source| Error::new(source, path))
 }
 
+pub use fs::Permissions;
+
+/// A wrapper around std::fs::set_permissions
+pub fn set_permissions<P: AsRef<Path>>(path: P, permissions: Permissions) -> Result<()> {
+    let path = path.as_ref();
+
+    fs::set_permissions(path, permissions).map_err(|source| Error::new(source, path))
+}
+
 /// A wrapper around std::fs::File that contains file path information in error
 /// cases.
 #[derive(Debug)]

src/tool_cache.rs

@@ -117,9 +117,20 @@ impl ToolCache {
             let exe_name = tool_identifier_to_exe_name(source, &version);
             tool_path.push(exe_name);
 
-            let mut output = BufWriter::new(File::create(tool_path).unwrap());
+            let mut output = BufWriter::new(File::create(&tool_path).unwrap());
             io::copy(&mut file, &mut output).unwrap();
 
+            // On Unix systems, we need to preserve permissions from the archive
+            // like executability.
+            #[cfg(unix)]
+            {
+                use std::os::unix::fs::PermissionsExt;
+
+                if let Some(mode) = file.unix_mode() {
+                    fs::set_permissions(&tool_path, fs::Permissions::from_mode(mode)).unwrap();
+                }
+            }
+
             log::trace!("Updating tool cache");
             let mut cache = Self::load().unwrap();
             let tool = cache.tools.entry(source.to_owned()).or_default();