Use goblin instead of shelling out to patchelf to get rpath

Changelog.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fix duplicated `Cargo.toml` of local dependencies in sdist in [#1114](https://github.com/PyO3/maturin/pull/1114)
 * Add support for Cargo workspace dependencies inheritance in [#1123](https://github.com/PyO3/maturin/pull/1123)
 * Add support for Cargo workspace metadata inheritance in [#1131](https://github.com/PyO3/maturin/pull/1131)
+* Use `goblin` instead of shelling out to `patchelf` to get rpath in [#1139](https://github.com/PyO3/maturin/pull/1139)
 
 ## [0.13.3] - 2022-09-15
 

src/auditwheel/patchelf.rs

@@ -78,18 +78,19 @@ pub fn set_rpath<S: AsRef<OsStr>>(file: impl AsRef<Path>, rpath: &S) -> Result<(
 }
 
 /// Get the `RPATH` of executables and libraries
-pub fn get_rpath(file: impl AsRef<Path>) -> Result<String> {
-    let mut cmd = Command::new("patchelf");
-    cmd.arg("--print-rpath").arg(file.as_ref());
-    let output = cmd
-        .output()
-        .context("Failed to execute 'patchelf', did you install it?")?;
-    if !output.status.success() {
-        bail!(
-            "patchelf --print-rpath failed: {}",
-            String::from_utf8_lossy(&output.stderr)
-        );
+pub fn get_rpath(file: impl AsRef<Path>) -> Result<Vec<String>> {
+    let file = file.as_ref();
+    let contents = fs_err::read(&file)?;
+    match goblin::Object::parse(&contents) {
+        Ok(goblin::Object::Elf(elf)) => {
+            let rpaths = if !elf.runpaths.is_empty() {
+                elf.runpaths
+            } else {
+                elf.rpaths
+            };
+            Ok(rpaths.iter().map(|r| r.to_string()).collect())
+        }
+        Ok(_) => bail!("'{}' is not an ELF file", file.display()),
+        Err(e) => bail!("Failed to parse ELF file at '{}': {}", file.display(), e),
     }
-    let rpath = String::from_utf8(output.stdout)?;
-    Ok(rpath.trim().to_string())
 }

src/build_context.rs

@@ -240,11 +240,10 @@ impl BuildContext {
                     continue;
                 }
                 let old_rpaths = patchelf::get_rpath(&artifact.path)?;
-                let mut new_rpaths: Vec<&str> =
-                    old_rpaths.split(':').filter(|r| !r.is_empty()).collect();
+                let mut new_rpaths = old_rpaths.clone();
                 for path in &artifact.linked_paths {
                     if !old_rpaths.contains(path) {
-                        new_rpaths.push(path);
+                        new_rpaths.push(path.to_string());
                     }
                 }
                 let new_rpath = new_rpaths.join(":");
@@ -364,13 +363,11 @@ impl BuildContext {
         // Currently artifact .so file always resides at ${module_name}/${module_name}.so
         let artifact_dir = Path::new(&self.module_name);
         for artifact in artifacts {
-            let old_rpaths = patchelf::get_rpath(&artifact.path)?;
+            let mut new_rpaths = patchelf::get_rpath(&artifact.path)?;
             // TODO: clean existing rpath entries if it's not pointed to a location within the wheel
             // See https://github.com/pypa/auditwheel/blob/353c24250d66951d5ac7e60b97471a6da76c123f/src/auditwheel/repair.py#L160
-            let mut new_rpaths: Vec<&str> =
-                old_rpaths.split(':').filter(|r| !r.is_empty()).collect();
             let new_rpath = Path::new("$ORIGIN").join(relpath(&libs_dir, artifact_dir));
-            new_rpaths.push(new_rpath.to_str().unwrap());
+            new_rpaths.push(new_rpath.to_str().unwrap().to_string());
             let new_rpath = new_rpaths.join(":");
             patchelf::set_rpath(&artifact.path, &new_rpath)?;
         }