1 files changed, 85 insertions, 0 deletions
diff --git a/lib/qcopy-acl.c b/lib/qcopy-acl.c
new file mode 100644
index 0000000..0f4159b
--- /dev/null
+++ b/lib/qcopy-acl.c
@@ -0,0 +1,85 @@
+/* Copy access control list from one file to another.  -*- coding: utf-8 -*-
+
+   Copyright (C) 2002-2003, 2005-2023 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+   Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible.  */
+
+#include <config.h>
+
+#include "acl.h"
+
+#include "acl-internal.h"
+
+#if USE_XATTR
+
+# include <attr/libattr.h>
+
+/* Returns 1 if NAME is the name of an extended attribute that is related
+   to permissions, i.e. ACLs.  Returns 0 otherwise.  */
+
+static int
+is_attr_permissions (const char *name, struct error_context *ctx)
+{
+  return attr_copy_action (name, ctx) == ATTR_ACTION_PERMISSIONS;
+}
+
+#endif  /* USE_XATTR */
+
+/* Copy access control lists from one file to another. If SOURCE_DESC is
+   a valid file descriptor, use file descriptor operations, else use
+   filename based operations on SRC_NAME. Likewise for DEST_DESC and
+   DST_NAME.
+   If access control lists are not available, fchmod the target file to
+   MODE.  Also sets the non-permission bits of the destination file
+   (S_ISUID, S_ISGID, S_ISVTX) to those from MODE if any are set.
+   Return 0 if successful.
+   Return -2 and set errno for an error relating to the source file.
+   Return -1 and set errno for an error relating to the destination file.  */
+
+int
+qcopy_acl (const char *src_name, int source_desc, const char *dst_name,
+           int dest_desc, mode_t mode)
+{
+  int ret;
+
+#ifdef USE_XATTR
+  /* in case no ACLs present and also to set higher mode bits
+     we chmod before setting ACLs as doing it after could overwrite them
+     (especially true for NFSv4, posix ACL has that ugly "mask" hack that
+     nobody understands) */
+  ret = chmod_or_fchmod (dst_name, dest_desc, mode);
+  /* Rather than fiddling with acls one by one, we just copy the whole ACL xattrs
+     (Posix or NFSv4). Of course, that won't address ACLs conversion
+     (i.e. posix <-> nfs4) but we can't do it anyway, so for now, we don't care
+     Functions attr_copy_* return 0 in case we copied something OR nothing
+     to copy */
+  if (ret == 0)
+    ret = source_desc <= 0 || dest_desc <= 0
+      ? attr_copy_file (src_name, dst_name, is_attr_permissions, NULL)
+      : attr_copy_fd (src_name, source_desc, dst_name, dest_desc,
+                      is_attr_permissions, NULL);
+#else
+  /* no XATTR, so we proceed the old dusty way */
+  struct permission_context ctx;
+
+  ret = get_permissions (src_name, source_desc, mode, &ctx);
+  if (ret != 0)
+    return -2;
+  ret = set_permissions (&ctx, dst_name, dest_desc);
+  free_permission_context (&ctx);
+#endif
+  return ret;
+}