darwin: preserve hardlinks on codesign/install_name_tool (#47808)

lib/spack/llnl/util/filesystem.py

@@ -24,6 +24,7 @@
     Callable,
     Deque,
     Dict,
+    Generator,
     Iterable,
     List,
     Match,
@@ -2838,6 +2839,25 @@ def temporary_dir(
         remove_directory_contents(tmp_dir)
 
 
+@contextmanager
+def edit_in_place_through_temporary_file(file_path: str) -> Generator[str, None, None]:
+    """Context manager for modifying ``file_path`` in place, preserving its inode and hardlinks,
+    for functions or external tools that do not support in-place editing. Notice that this function
+    is unsafe in that it works with paths instead of a file descriptors, but this is by design,
+    since we assume the call site will create a new inode at the same path."""
+    tmp_fd, tmp_path = tempfile.mkstemp(
+        dir=os.path.dirname(file_path), prefix=f"{os.path.basename(file_path)}."
+    )
+    # windows cannot replace a file with open fds, so close since the call site needs to replace.
+    os.close(tmp_fd)
+    try:
+        shutil.copyfile(file_path, tmp_path, follow_symlinks=True)
+        yield tmp_path
+        shutil.copyfile(tmp_path, file_path, follow_symlinks=True)
+    finally:
+        os.unlink(tmp_path)
+
+
 def filesummary(path, print_bytes=16) -> Tuple[int, bytes]:
     """Create a small summary of the given file. Does not error
     when file does not exist.

lib/spack/spack/binary_distribution.py

@@ -2332,7 +2332,9 @@ def is_backup_file(file):
             if not codesign:
                 return
             for binary in changed_files:
-                codesign("-fs-", binary)
+                # preserve the original inode by running codesign on a copy
+                with fsys.edit_in_place_through_temporary_file(binary) as tmp_binary:
+                    codesign("-fs-", tmp_binary)
 
     # If we are installing back to the same location
     # relocate the sbang location if the spack directory changed

lib/spack/spack/relocate.py

@@ -13,6 +13,7 @@
 import macholib.mach_o
 import macholib.MachO
 
+import llnl.util.filesystem as fs
 import llnl.util.lang
 import llnl.util.tty as tty
 from llnl.util.lang import memoized
@@ -275,10 +276,10 @@ def modify_macho_object(cur_path, rpaths, deps, idpath, paths_to_paths):
 
     # Deduplicate and flatten
     args = list(itertools.chain.from_iterable(llnl.util.lang.dedupe(args)))
-    if args:
-        args.append(str(cur_path))
     install_name_tool = executable.Executable("install_name_tool")
-        install_name_tool(*args)
+    if args:
+        with fs.edit_in_place_through_temporary_file(cur_path) as temp_path:
+            install_name_tool(*args, temp_path)
 
 
 def macholib_get_paths(cur_path):
@@ -717,8 +718,8 @@ def fixup_macos_rpath(root, filename):
         # No fixes needed
         return False
 
-    args.append(abspath)
-    executable.Executable("install_name_tool")(*args)
+    with fs.edit_in_place_through_temporary_file(abspath) as temp_path:
+        executable.Executable("install_name_tool")(*args, temp_path)
     return True
 
 

lib/spack/spack/test/llnl/util/filesystem.py

@@ -1249,3 +1249,14 @@ def test_find_input_types(tmp_path: pathlib.Path):
 
     with pytest.raises(TypeError):
         fs.find(1, "file.txt")  # type: ignore
+
+
+def test_edit_in_place_through_temporary_file(tmp_path):
+    (tmp_path / "example.txt").write_text("Hello")
+    current_ino = os.stat(tmp_path / "example.txt").st_ino
+    with fs.edit_in_place_through_temporary_file(tmp_path / "example.txt") as temporary:
+        os.unlink(temporary)
+        with open(temporary, "w") as f:
+            f.write("World")
+    assert (tmp_path / "example.txt").read_text() == "World"
+    assert os.stat(tmp_path / "example.txt").st_ino == current_ino

lib/spack/spack/util/filesystem.py

@@ -13,7 +13,7 @@
 import sys
 
 from llnl.util import tty
-from llnl.util.filesystem import join_path
+from llnl.util.filesystem import edit_in_place_through_temporary_file
 from llnl.util.lang import memoized
 
 from spack.util.executable import Executable, which
@@ -81,12 +81,11 @@ def fix_darwin_install_name(path):
     Parameters:
         path (str): directory in which .dylib files are located
     """
-    libs = glob.glob(join_path(path, "*.dylib"))
-    for lib in libs:
-        # fix install name first:
+    libs = glob.glob(os.path.join(path, "*.dylib"))
     install_name_tool = Executable("install_name_tool")
-        install_name_tool("-id", lib, lib)
     otool = Executable("otool")
+    for lib in libs:
+        args = ["-id", lib]
         long_deps = otool("-L", lib, output=str).split("\n")
         deps = [dep.partition(" ")[0][1::] for dep in long_deps[2:-1]]
         # fix all dependencies:
@@ -98,5 +97,8 @@ def fix_darwin_install_name(path):
                 # but we don't know builddir (nor how symbolic links look
                 # in builddir). We thus only compare the basenames.
                 if os.path.basename(dep) == os.path.basename(loc):
-                    install_name_tool("-change", dep, loc, lib)
+                    args.extend(("-change", dep, loc))
                     break
+
+        with edit_in_place_through_temporary_file(lib) as tmp:
+            install_name_tool(*args, tmp)