1 files changed, 99 insertions, 0 deletions
diff --git a/lib/libc/posix1e/acl_equiv_mode_np.c b/lib/libc/posix1e/acl_equiv_mode_np.c
new file mode 100644
index 000000000000..333b010541ee
--- /dev/null
+++ b/lib/libc/posix1e/acl_equiv_mode_np.c
@@ -0,0 +1,99 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Gleb Popov
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * acl_equiv_mode_np: Check if an ACL can be represented as a mode_t.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/stat.h>
+#include <sys/acl.h>
+
+#include "acl_support.h"
+
+int
+acl_equiv_mode_np(acl_t acl, mode_t *mode_p)
+{
+	mode_t ret_mode = 0;
+
+	if (acl == NULL) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+	/* Linux returns 0 for ACL returned by acl_init() */
+	if (_acl_brand(acl) == ACL_BRAND_UNKNOWN && acl->ats_acl.acl_cnt == 0)
+		goto done;
+
+	// TODO: Do we want to handle ACL_BRAND_NFS4 in this function? */
+	if (_acl_brand(acl) != ACL_BRAND_POSIX)
+		return (1);
+
+	for (int cur_entry = 0; cur_entry < acl->ats_acl.acl_cnt; cur_entry++) {
+		acl_entry_t entry = &acl->ats_acl.acl_entry[cur_entry];
+
+		if ((entry->ae_perm & ACL_PERM_BITS) != entry->ae_perm)
+			return (1);
+
+		switch (entry->ae_tag) {
+		case ACL_USER_OBJ:
+			if (entry->ae_perm & ACL_READ)
+				ret_mode |= S_IRUSR;
+			if (entry->ae_perm & ACL_WRITE)
+				ret_mode |= S_IWUSR;
+			if (entry->ae_perm & ACL_EXECUTE)
+				ret_mode |= S_IXUSR;
+			break;
+		case ACL_GROUP_OBJ:
+			if (entry->ae_perm & ACL_READ)
+				ret_mode |= S_IRGRP;
+			if (entry->ae_perm & ACL_WRITE)
+				ret_mode |= S_IWGRP;
+			if (entry->ae_perm & ACL_EXECUTE)
+				ret_mode |= S_IXGRP;
+			break;
+		case ACL_OTHER:
+			if (entry->ae_perm & ACL_READ)
+				ret_mode |= S_IROTH;
+			if (entry->ae_perm & ACL_WRITE)
+				ret_mode |= S_IWOTH;
+			if (entry->ae_perm & ACL_EXECUTE)
+				ret_mode |= S_IXOTH;
+			break;
+		default:
+			return (1);
+		}
+	}
+
+done:
+	if (mode_p != NULL)
+		*mode_p = ret_mode;
+
+	return (0);
+}