Symlink in the exec-root so that relative paths will work, unchanged.

cargo/cargo_build_script_runner/bin.rs

@@ -53,6 +53,46 @@ fn run_buildrs() -> Result<(), String> {
  create_dir_all(&out_dir_abs)
  .unwrap_or_else(|_| panic!("Failed to make output directory: {:?}", out_dir_abs));
 
+ // Symlink the execroot to the manifest_dir so that we can use relative paths in the arguments.
+ let exec_root_paths = std::fs::read_dir(&exec_root)
+ .map_err(|err| format!("Failed while listing exec root: {:?}", err))?;
+ for path in exec_root_paths {
+ let path = path
+ .map_err(|err| {
+ format!(
+ "Failed while getting path from exec root listing: {:?}",
+ err
+ )
+ })?
+ .path();
+ let metadata = std::fs::metadata(&path).map_err(|err| {
+ format!(
+ "Failed while getting metadata for path {:?}: {:?}",
+ path, err
+ )
+ })?;
+
+ // Only symlink directories.
+ if !metadata.is_dir() {
+ continue;
+ }
+
+ let dir_name = path
+ .file_name()
+ .ok_or_else(|| "Failed while getting file name".to_string())?
+ .to_str()
+ .ok_or_else(|| "Failed while converting file name to string".to_string())?;
+ let link = manifest_dir.join(dir_name);
+
+ // If the link already exists, don't try to create it.
+ if link.exists() {
+ continue;
+ }
+
+ symlink(&path, &link)
+ .map_err(|err| format!("Failed to symlink {:?} to {:?}: {}", path, link, err))?;
+ }
+
  let target_env_vars =
  get_target_env_vars(&rustc_env).expect("Error getting target env vars from rustc");
 
@@ -174,6 +214,26 @@ fn run_buildrs() -> Result<(), String> {
  Ok(())
 }
 
+/// Create a symlink from `link` to `original`.
+///
+/// Link must be a directory.
+#[cfg(windows)]
+fn symlink(original: &Path, link: &Path) -> Result<(), String> {
+ if let Err(e) = std::os::windows::fs::symlink_dir(original, link) {
+ return Err(format!("Failed to create symlink: {}", e));
+ }
+ Ok(())
+}
+
+/// Create a symlink from `link` to `original`.
+#[cfg(not(windows))]
+fn symlink(original: &Path, link: &Path) -> Result<(), String> {
+ if let Err(e) = std::os::unix::fs::symlink(original, link) {
+ return Err(format!("Failed to create symlink: {}", e));
+ }
+ Ok(())
+}
+
 /// A representation of expected command line arguments.
 struct Options {
  progname: String,