1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2017, Lawrence Livermore National Security, LLC.
23 */
24
25 #include <fcntl.h>
26 #include <stdlib.h>
27 #include <stdio.h>
28 #include <sys/types.h>
29 #include <sys/stat.h>
30 #include <sys/systeminfo.h>
31
32 static unsigned long
get_spl_hostid(void)33 get_spl_hostid(void)
34 {
35 FILE *f;
36 unsigned long hostid;
37 char *env;
38
39 /*
40 * Allow the hostid to be subverted for testing.
41 */
42 env = getenv("ZFS_HOSTID");
43 if (env) {
44 hostid = strtoull(env, NULL, 0);
45 return (hostid & HOSTID_MASK);
46 }
47
48 f = fopen("/sys/module/spl/parameters/spl_hostid", "r");
49 if (!f)
50 return (0);
51
52 if (fscanf(f, "%lu", &hostid) != 1)
53 hostid = 0;
54
55 fclose(f);
56
57 return (hostid & HOSTID_MASK);
58 }
59
60 unsigned long
get_system_hostid(void)61 get_system_hostid(void)
62 {
63 unsigned long system_hostid = get_spl_hostid();
64 /*
65 * We do not use the library call gethostid() because
66 * it generates a hostid value that the kernel is
67 * unaware of, if the spl_hostid module parameter has not
68 * been set and there is no system hostid file (e.g.
69 * /etc/hostid). The kernel and userspace must agree.
70 * See comments above hostid_read() in the SPL.
71 */
72 if (system_hostid == 0) {
73 int fd, rc;
74 unsigned long hostid;
75 int hostid_size = 4; /* 4 bytes regardless of arch */
76
77 fd = open("/etc/hostid", O_RDONLY);
78 if (fd >= 0) {
79 rc = read(fd, &hostid, hostid_size);
80 if (rc > 0)
81 system_hostid = (hostid & HOSTID_MASK);
82 close(fd);
83 }
84 }
85 return (system_hostid);
86 }
87