1 /* $NetBSD: clock_settime.c,v 1.3 2001/12/09 16:11:45 manu Exp $ */ 2 3 /* 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Emmanuel Dreyfus. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include "namespace.h" 35 36 #include <sys/types.h> 37 #include <sys/ioctl.h> 38 #include <sys/syscall.h> 39 #include <sys/systm.h> 40 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <paths.h> 44 #include <string.h> 45 #include <time.h> 46 #include <unistd.h> 47 48 #include <sys/clockctl.h> 49 50 #ifdef __weak_alias 51 __weak_alias(clock_settime,_clock_settime) 52 #endif 53 54 extern int __clockctl_fd; 55 56 int 57 clock_settime(clock_id, tp) 58 clockid_t clock_id; 59 const struct timespec *tp; 60 { 61 struct sys_clock_settime_args args; 62 int error; 63 quad_t q; 64 int rv; 65 66 /* 67 * if __clockctl_fd == -1, then this is not our first time, 68 * and we know root is the calling user. We use the system call 69 */ 70 if (__clockctl_fd == -1) { 71 try_syscall: 72 q = __syscall((quad_t)SYS_clock_settime, clock_id, tp); 73 if (/* LINTED constant */ sizeof (quad_t) == sizeof (register_t) 74 || /* LINTED constant */ BYTE_ORDER == LITTLE_ENDIAN) 75 rv = (int)q; 76 else 77 rv = (int)((u_quad_t)q >> 32); 78 79 /* 80 * If credentials changed from root to an unprivilegied 81 * user, and we already had __clockctl_fd = -1, then we 82 * tried the system call as a non root user, it failed 83 * with EPERM, and we will try clockctl. 84 */ 85 if (rv != -1 || errno != EPERM) 86 return rv; 87 __clockctl_fd = -2; 88 } 89 90 /* 91 * If __clockctl_fd = -2 then this is our first time here, 92 * or credentials have changed (the calling process dropped root 93 * root privilege). Check if root is the calling user. If it is, 94 * we try the system call, if it is not, we try clockctl. 95 */ 96 if (__clockctl_fd == -2) { 97 /* 98 * Root always uses the syscall 99 */ 100 if (geteuid() == 0) { 101 __clockctl_fd = -1; 102 goto try_syscall; 103 } 104 105 /* 106 * If this fails, it means that we are not root 107 * and we cannot open clockctl. This is a failure. 108 */ 109 __clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY, 0); 110 if (__clockctl_fd == -1) 111 return -1; 112 } 113 114 /* 115 * If __clockctl_fd >=0, clockctl has already been open 116 * and used, so we carry on using it. 117 */ 118 SCARG(&args, clock_id) = clock_id; 119 SCARG(&args, tp) = tp; 120 error = ioctl(__clockctl_fd, CLOCKCTL_CLOCK_SETTIME, &args); 121 return error; 122 123 } 124