rust: wrapper check executables in PATH

rust/bear/src/bin/wrapper.rs

@@ -22,6 +22,9 @@ use bear::intercept::tcp::ReporterOnTcp;
 use bear::intercept::Reporter;
 use bear::intercept::KEY_DESTINATION;
 use bear::intercept::{Event, Execution, ProcessId};
+use std::ffi::OsStr;
+#[cfg(target_os = "windows")]
+use std::ffi::OsStr;
 use std::path::{Path, PathBuf};
 
 /// Implementation of the wrapper process.
@@ -85,8 +88,7 @@ fn next_in_path(target: &Path) -> Result<PathBuf> {
 
     path.split(':')
         .map(|dir| Path::new(dir).join(target))
-        // FIXME: check if it is executable
-        .filter(|path| path.is_file())
+        .filter(|path| is_executable_file(path))
         .find(|path| {
             // We need to compare it with the real path of the candidate executable to avoid
             // calling the same executable again.
@@ -127,3 +129,34 @@ fn into_execution(path_buf: &Path) -> Result<Execution> {
             environment: std::env::vars().collect(),
         })
 }
+
+/// Checks if the given path is an executable file.
+fn is_executable_file(path: &Path) -> bool {
+    if !path.is_file() {
+        return false;
+    }
+
+    #[cfg(target_os = "windows")]
+    {
+        path.extension()
+            .map(|ext| EXECUTABLE_EXTENSIONS.contains(&ext))
+            .unwrap_or(false)
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        std::fs::metadata(path)
+            .map(|metadata| metadata.permissions().mode() & 0o100 != 0)
+            .unwrap_or(false)
+    }
+}
+
+#[cfg(target_os = "windows")]
+const EXECUTABLE_EXTENSIONS: &[&OsStr] = &[
+    OsStr::new("exe"),
+    OsStr::new("com"),
+    OsStr::new("bat"),
+    OsStr::new("cmd"),
+    OsStr::new("ps1"),
+];