libspl: move SID implementation from libzpool

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #17861

lib/libspl/Makefile.am

@@ -29,6 +29,7 @@ libspl_la_SOURCES = \
 	%D%/procfs_list.c \
 	%D%/random.c \
 	%D%/rwlock.c \
+	%D%/sid.c \
 	%D%/strlcat.c \
 	%D%/strlcpy.c \
 	%D%/taskq.c \

lib/libspl/sid.c

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2016 Actifio, Inc. All rights reserved.
+ * Copyright (c) 2025, Klara, Inc.
+ */
+
+#include <sys/sid.h>
+#include <umem.h>
+
+ksiddomain_t *
+ksid_lookupdomain(const char *dom)
+{
+	ksiddomain_t *kd;
+
+	kd = umem_zalloc(sizeof (ksiddomain_t), UMEM_NOFAIL);
+	kd->kd_name = strdup(dom);
+	return (kd);
+}
+
+void
+ksiddomain_rele(ksiddomain_t *ksid)
+{
+	free(ksid->kd_name);
+	umem_free(ksid, sizeof (ksiddomain_t));
+}

lib/libzpool/kernel.c

@@ -510,23 +510,6 @@ secpolicy_zfs(const cred_t *cr)
 	return (0);
 }
 
-ksiddomain_t *
-ksid_lookupdomain(const char *dom)
-{
-	ksiddomain_t *kd;
-
-	kd = umem_zalloc(sizeof (ksiddomain_t), UMEM_NOFAIL);
-	kd->kd_name = spa_strdup(dom);
-	return (kd);
-}
-
-void
-ksiddomain_rele(ksiddomain_t *ksid)
-{
-	spa_strfree(ksid->kd_name);
-	umem_free(ksid, sizeof (ksiddomain_t));
-}
-
 zfs_file_t *
 zfs_onexit_fd_hold(int fd, minor_t *minorp)
 {