bitbake: lib/bb: Add xattr and acl libraries

Adds Python wrappers around the xattr API from libc and the ACL API from
libacl.

(Bitbake rev: 538011256964d0253f8e3ab7ff1d6fd62c7c2f89)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 126 insertions, 0 deletions

diff --git a/bitbake/lib/bb/xattr.py b/bitbake/lib/bb/xattr.py
new file mode 100755
index 0000000000..7b634944a4
--- /dev/null
+++ b/bitbake/lib/bb/xattr.py
@@ -0,0 +1,126 @@
+#! /usr/bin/env python3
+#
+# Copyright 2023 by Garmin Ltd. or its subsidiaries
+#
+# SPDX-License-Identifier: MIT
+
+import sys
+import ctypes
+import os
+import errno
+
+libc = ctypes.CDLL("libc.so.6", use_errno=True)
+fsencoding = sys.getfilesystemencoding()
+
+
+libc.listxattr.argtypes = [ctypes.c_char_p, ctypes.c_char_p, ctypes.c_size_t]
+libc.llistxattr.argtypes = [ctypes.c_char_p, ctypes.c_char_p, ctypes.c_size_t]
+
+
+def listxattr(path, follow=True):
+    func = libc.listxattr if follow else libc.llistxattr
+
+    os_path = os.fsencode(path)
+
+    while True:
+        length = func(os_path, None, 0)
+
+        if length < 0:
+            err = ctypes.get_errno()
+            raise OSError(err, os.strerror(err), str(path))
+
+        if length == 0:
+            return []
+
+        arr = ctypes.create_string_buffer(length)
+
+        read_length = func(os_path, arr, length)
+        if read_length != length:
+            # Race!
+            continue
+
+        return [a.decode(fsencoding) for a in arr.raw.split(b"\x00") if a]
+
+
+libc.getxattr.argtypes = [
+    ctypes.c_char_p,
+    ctypes.c_char_p,
+    ctypes.c_char_p,
+    ctypes.c_size_t,
+]
+libc.lgetxattr.argtypes = [
+    ctypes.c_char_p,
+    ctypes.c_char_p,
+    ctypes.c_char_p,
+    ctypes.c_size_t,
+]
+
+
+def getxattr(path, name, follow=True):
+    func = libc.getxattr if follow else libc.lgetxattr
+
+    os_path = os.fsencode(path)
+    os_name = os.fsencode(name)
+
+    while True:
+        length = func(os_path, os_name, None, 0)
+
+        if length < 0:
+            err = ctypes.get_errno()
+            if err == errno.ENODATA:
+                return None
+            raise OSError(err, os.strerror(err), str(path))
+
+        if length == 0:
+            return ""
+
+        arr = ctypes.create_string_buffer(length)
+
+        read_length = func(os_path, os_name, arr, length)
+        if read_length != length:
+            # Race!
+            continue
+
+        return arr.raw
+
+
+def get_all_xattr(path, follow=True):
+    attrs = {}
+
+    names = listxattr(path, follow)
+
+    for name in names:
+        value = getxattr(path, name, follow)
+        if value is None:
+            # This can happen if a value is erased after listxattr is called,
+            # so ignore it
+            continue
+        attrs[name] = value
+
+    return attrs
+
+
+def main():
+    import argparse
+    from pathlib import Path
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("path", help="File Path", type=Path)
+
+    args = parser.parse_args()
+
+    attrs = get_all_xattr(args.path)
+
+    for name, value in attrs.items():
+        try:
+            value = value.decode(fsencoding)
+        except UnicodeDecodeError:
+            pass
+
+        print(f"{name} = {value}")
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())