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 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 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