1 files changed, 84 insertions, 0 deletions
diff --git a/sys/contrib/openzfs/lib/libspl/os/linux/gethostid.c b/sys/contrib/openzfs/lib/libspl/os/linux/gethostid.c
new file mode 100644
index 000000000000..d39f3dda3b8d
--- /dev/null
+++ b/sys/contrib/openzfs/lib/libspl/os/linux/gethostid.c
@@ -0,0 +1,84 @@
+// 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) 2017, Lawrence Livermore National Security, LLC.
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/systeminfo.h>
+
+static unsigned long
+get_spl_hostid(void)
+{
+	FILE *f;
+	unsigned long hostid;
+	char *env;
+
+	/*
+	 * Allow the hostid to be subverted for testing.
+	 */
+	env = getenv("ZFS_HOSTID");
+	if (env)
+		return (strtoull(env, NULL, 0));
+
+	f = fopen("/proc/sys/kernel/spl/hostid", "re");
+	if (!f)
+		return (0);
+
+	if (fscanf(f, "%lx", &hostid) != 1)
+		hostid = 0;
+
+	fclose(f);
+
+	return (hostid);
+}
+
+unsigned long
+get_system_hostid(void)
+{
+	unsigned long hostid = get_spl_hostid();
+	uint32_t system_hostid;
+
+	/*
+	 * We do not use gethostid(3) because it can return a bogus ID,
+	 * depending on the libc and /etc/hostid presence,
+	 * and the kernel and userspace must agree.
+	 * See comments above hostid_read() in the SPL.
+	 */
+	if (hostid == 0) {
+		int fd = open("/etc/hostid", O_RDONLY | O_CLOEXEC);
+		if (fd >= 0) {
+			if (read(fd, &system_hostid, sizeof (system_hostid))
+			    != sizeof (system_hostid))
+				hostid = 0;
+			else
+				hostid = system_hostid;
+			(void) close(fd);
+		}
+	}
+
+	return (hostid & HOSTID_MASK);
+}