1 files changed, 87 insertions, 0 deletions
diff --git a/taskcluster/scripts/misc/unpack-sdk.py b/taskcluster/scripts/misc/unpack-sdk.py
new file mode 100644
index 0000000000..290370db42
--- /dev/null
+++ b/taskcluster/scripts/misc/unpack-sdk.py
@@ -0,0 +1,87 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import hashlib
+import os
+import shutil
+import stat
+import sys
+import tempfile
+from io import BytesIO
+from urllib.request import urlopen
+
+from mozpack.macpkg import Pbzx, uncpio, unxar
+
+
+def unpack_sdk(url, sha256, extract_prefix, out_dir="."):
+    with tempfile.TemporaryFile() as pkg:
+        hash = hashlib.sha256()
+        with urlopen(url) as fh:
+            # Equivalent to shutil.copyfileobj, but computes sha256 at the same time.
+            while True:
+                buf = fh.read(1024 * 1024)
+                if not buf:
+                    break
+                hash.update(buf)
+                pkg.write(buf)
+        digest = hash.hexdigest()
+        if digest != sha256:
+            raise Exception(f"(actual) {digest} != (expected) {sha256}")
+
+        pkg.seek(0, os.SEEK_SET)
+
+        for name, content in unxar(pkg):
+            if name in ("Payload", "Content"):
+                extract_payload(content, extract_prefix, out_dir)
+
+
+def extract_payload(fileobj, extract_prefix, out_dir="."):
+    hardlinks = {}
+    for path, st, content in uncpio(Pbzx(fileobj)):
+        # When there are hardlinks, normally a cpio stream is supposed to
+        # contain the data for all of them, but, even with compression, that
+        # can be a waste of space, so in some cpio streams (*cough* *cough*,
+        # Apple's, e.g. in Xcode), the files after the first one have dummy
+        # data.
+        # As we may be filtering the first file out (if it doesn't match
+        # extract_prefix), we need to keep its data around (we're not going
+        # to be able to rewind).
+        # We could do something fancy in the case where the first file is not
+        # filtered out, but in practice, it's not worth the extra complexity.
+        if stat.S_ISREG(st.mode) and st.nlink > 1:
+            key = (st.dev, st.ino)
+            hardlink = hardlinks.get(key)
+            if hardlink:
+                hardlink[0] -= 1
+                if hardlink[0] == 0:
+                    del hardlinks[key]
+            else:
+                hardlink = hardlinks[key] = [st.nlink - 1, BytesIO(content.read())]
+            content = hardlink[1]
+            content.seek(0)
+
+        if not path:
+            continue
+        path = path.decode()
+        if not path.startswith(extract_prefix):
+            continue
+        path = os.path.join(out_dir, path[len(extract_prefix) :].lstrip("/"))
+        if stat.S_ISDIR(st.mode):
+            os.makedirs(path, exist_ok=True)
+        else:
+            parent = os.path.dirname(path)
+            if parent:
+                os.makedirs(parent, exist_ok=True)
+
+            if stat.S_ISLNK(st.mode):
+                os.symlink(content.read(), path)
+            elif stat.S_ISREG(st.mode):
+                with open(path, "wb") as out:
+                    shutil.copyfileobj(content, out)
+            else:
+                raise Exception(f"File mode {st.mode:o} is not supported")
+
+
+if __name__ == "__main__":
+    unpack_sdk(*sys.argv[1:])