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 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 return (strtoull(env, NULL, 0)); 45 46 f = fopen("/proc/sys/kernel/spl/hostid", "re"); 47 if (!f) 48 return (0); 49 50 if (fscanf(f, "%lx", &hostid) != 1) 51 hostid = 0; 52 53 fclose(f); 54 55 return (hostid); 56 } 57 58 unsigned long 59 get_system_hostid(void) 60 { 61 unsigned long hostid = get_spl_hostid(); 62 63 /* 64 * We do not use gethostid(3) because it can return a bogus ID, 65 * depending on the libc and /etc/hostid presence, 66 * and the kernel and userspace must agree. 67 * See comments above hostid_read() in the SPL. 68 */ 69 if (hostid == 0) { 70 int fd = open("/etc/hostid", O_RDONLY | O_CLOEXEC); 71 if (fd >= 0) { 72 if (read(fd, &hostid, 4) < 0) 73 hostid = 0; 74 (void) close(fd); 75 } 76 } 77 78 return (hostid & HOSTID_MASK); 79 } 80