1 files changed, 112 insertions, 0 deletions
diff --git a/lib/libc/posix1e/acl_from_mode_np.c b/lib/libc/posix1e/acl_from_mode_np.c
new file mode 100644
index 000000000000..3d4135770917
--- /dev/null
+++ b/lib/libc/posix1e/acl_from_mode_np.c
@@ -0,0 +1,112 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Robert N M Watson, 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_from_mode_np: Create an ACL from a mode_t.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/acl.h>
+#include <sys/stat.h>
+
+/*
+ * return an ACL corresponding to the permissions
+ * contained in mode_t
+ */
+acl_t
+acl_from_mode_np(const mode_t mode)
+{
+	acl_t acl;
+	acl_entry_t entry;
+	acl_permset_t perms;
+
+	/* create the ACL */
+	acl = acl_init(3);
+	/* here and below, the only possible reason to fail is ENOMEM, so
+	 * no need to set errno again
+	 */
+	if (acl == NULL)
+		return (NULL);
+
+	/* First entry: ACL_USER_OBJ */
+	if (acl_create_entry(&acl, &entry) == -1)
+		return (NULL);
+	/* TODO: need to handle error there and below? */
+	acl_set_tag_type(entry, ACL_USER_OBJ);
+
+	acl_get_permset(entry, &perms);
+	acl_clear_perms(perms);
+
+	/* calculate user mode */
+	if (mode & S_IRUSR)
+		acl_add_perm(perms, ACL_READ);
+	if (mode & S_IWUSR)
+		acl_add_perm(perms, ACL_WRITE);
+	if (mode & S_IXUSR)
+		acl_add_perm(perms, ACL_EXECUTE);
+
+	acl_set_permset(entry, perms);
+
+	/* Second entry: ACL_GROUP_OBJ */
+	if (acl_create_entry(&acl, &entry) == -1)
+		return (NULL);
+	acl_set_tag_type(entry, ACL_GROUP_OBJ);
+
+	acl_get_permset(entry, &perms);
+	acl_clear_perms(perms);
+
+	/* calculate group mode */
+	if (mode & S_IRGRP)
+		acl_add_perm(perms, ACL_READ);
+	if (mode & S_IWGRP)
+		acl_add_perm(perms, ACL_WRITE);
+	if (mode & S_IXGRP)
+		acl_add_perm(perms, ACL_EXECUTE);
+
+	acl_set_permset(entry, perms);
+
+	/* Third entry: ACL_OTHER */
+	if (acl_create_entry(&acl, &entry) == -1)
+		return (NULL);
+	acl_set_tag_type(entry, ACL_OTHER);
+
+	acl_get_permset(entry, &perms);
+	acl_clear_perms(perms);
+
+	/* calculate other mode */
+	if (mode & S_IROTH)
+		acl_add_perm(perms, ACL_READ);
+	if (mode & S_IWOTH)
+		acl_add_perm(perms, ACL_WRITE);
+	if (mode & S_IXOTH)
+		acl_add_perm(perms, ACL_EXECUTE);
+
+	acl_set_permset(entry, perms);
+
+	return (acl);
+}