fuse: we need the binary ACL representation

Author: ThomasWaldmann

src/borg/fuse.py

@@ -44,7 +44,7 @@ def async_wrapper(fn):
 from .helpers import msgpack
 from .helpers.lrucache import LRUCache
 from .item import Item
-from .platform import uid2user, gid2group
+from .platform import uid2user, gid2group, get_binary_acl
 from .platformflags import is_darwin
 from .repository import Repository
 from .remote import RemoteRepository
@@ -642,9 +642,9 @@ def getxattr(self, inode, name, ctx=None):
         item = self.get_item(inode)
         try:
             if name == b"system.posix_acl_access":
-                return item["acl_access"]
+                return get_binary_acl(item, "acl_access", self.numeric_ids)
             elif name == b"system.posix_acl_default":
-                return item["acl_default"]
+                return get_binary_acl(item, "acl_default", self.numeric_ids)
             else:
                 return item.get("xattrs", {})[name] or b""
         except KeyError:

src/borg/platform/__init__.py

@@ -13,7 +13,7 @@
 if is_linux:  # pragma: linux only
     from .linux import API_VERSION as OS_API_VERSION
     from .linux import listxattr, getxattr, setxattr
-    from .linux import acl_get, acl_set
+    from .linux import acl_get, acl_set, get_binary_acl
     from .linux import set_flags, get_flags
     from .linux import SyncFile
     from .posix import process_alive, local_pid_alive
@@ -23,7 +23,7 @@
 elif is_freebsd:  # pragma: freebsd only
     from .freebsd import API_VERSION as OS_API_VERSION
     from .freebsd import listxattr, getxattr, setxattr
-    from .freebsd import acl_get, acl_set
+    from .freebsd import acl_get, acl_set, get_binary_acl
     from .base import set_flags, get_flags
     from .base import SyncFile
     from .posix import process_alive, local_pid_alive
@@ -33,7 +33,7 @@
 elif is_darwin:  # pragma: darwin only
     from .darwin import API_VERSION as OS_API_VERSION
     from .darwin import listxattr, getxattr, setxattr
-    from .darwin import acl_get, acl_set
+    from .darwin import acl_get, acl_set, get_binary_acl
     from .darwin import is_darwin_feature_64_bit_inode, _get_birthtime_ns
     from .base import set_flags, get_flags
     from .base import SyncFile
@@ -45,7 +45,7 @@
     # generic stuff for all other posix OSes
     OS_API_VERSION = API_VERSION
     from .base import listxattr, getxattr, setxattr
-    from .base import acl_get, acl_set
+    from .base import acl_get, acl_set, get_binary_acl
     from .base import set_flags, get_flags
     from .base import SyncFile
     from .posix import process_alive, local_pid_alive

src/borg/platform/base.py

@@ -81,6 +81,13 @@ def acl_set(path, item, numeric_ids=False, fd=None):
     """
 
 
+def get_binary_acl(item, key, numeric_ids=False):
+    """
+    Get binary ACL data for item and key (acl name).
+    """
+    raise KeyError(key)
+
+
 try:
     from os import lchflags  # type: ignore[attr-defined]
 

src/borg/platform/darwin.pyx

@@ -5,6 +5,7 @@ from libc cimport errno
 from posix.time cimport timespec
 
 from .posix import user2uid, group2gid
+from .base import get_binary_acl  # dummy
 from ..helpers import safe_decode, safe_encode
 from .xattr import _listxattr_inner, _getxattr_inner, _setxattr_inner, split_string0
 

src/borg/platform/freebsd.pyx

@@ -4,6 +4,7 @@ import stat
 from libc cimport errno
 
 from .posix import posix_acl_use_stored_uid_gid
+from .base import get_binary_acl  # dummy
 from ..helpers import safe_encode, safe_decode
 from .xattr import _listxattr_inner, _getxattr_inner, _setxattr_inner, split_lstring
 

src/borg/platform/linux.pyx

@@ -1,3 +1,5 @@
+from cpython.bytes cimport PyBytes_FromStringAndSize
+
 import os
 import re
 import stat
@@ -48,6 +50,7 @@ cdef extern from "sys/acl.h":
     int acl_set_fd(int fd, acl_t acl)
     acl_t acl_from_text(const char *buf)
     char *acl_to_text(acl_t acl, ssize_t *len)
+    ssize_t acl_size(acl_t)
 
 cdef extern from "acl/libacl.h":
     int acl_extended_file_nofollow(const char *path)
@@ -321,6 +324,29 @@ def acl_set(path, item, numeric_ids=False, fd=None):
             acl_free(default_acl)
 
 
+def get_binary_acl(item, key, numeric_ids=False):
+    assert key in ("acl_access", "acl_default")
+    cdef acl_t acl = NULL
+    cdef ssize_t size
+
+    if numeric_ids:
+        converter = posix_acl_use_stored_uid_gid
+    else:
+        converter = acl_use_local_uid_gid
+    acl_text = item[key]
+    try:
+        acl = acl_from_text(<bytes>converter(acl_text))
+        if acl == NULL:
+            raise OSError(errno.errno, os.strerror(errno.errno), os.fsdecode(item.path))
+        size = acl_size(acl)
+        if size < 0:
+            raise OSError(errno.errno, "Failed to get ACL size")
+        # Create a bytes object from the ACL data structure:
+        return PyBytes_FromStringAndSize(<char *> acl, size)
+    finally:
+        acl_free(acl)
+
+
 cdef _sync_file_range(fd, offset, length, flags):
     assert offset & PAGE_MASK == 0, "offset %d not page-aligned" % offset
     assert length & PAGE_MASK == 0, "length %d not page-aligned" % length