1 /* $NetBSD: ntp_adjtime.c,v 1.8 2006/10/07 20:02:01 kardel 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 <sys/cdefs.h> 35 #if defined(LIBC_SCCS) && !defined(lint) 36 __RCSID("$NetBSD: ntp_adjtime.c,v 1.8 2006/10/07 20:02:01 kardel Exp $"); 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include "namespace.h" 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <paths.h> 43 #include <unistd.h> 44 #include <sys/types.h> 45 #include <sys/time.h> 46 #include <sys/timex.h> 47 #include <sys/ioctl.h> 48 #include <sys/syscall.h> 49 50 #include <sys/clockctl.h> 51 52 #include <fcntl.h> 53 #include <paths.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #ifdef __weak_alias 58 __weak_alias(ntp_adjtime,_ntp_adjtime) 59 #endif 60 61 extern int __clockctl_fd; 62 63 int 64 ntp_adjtime(tp) 65 struct timex *tp; 66 { 67 struct clockctl_ntp_adjtime args; 68 int error; 69 quad_t q; 70 int rv; 71 72 /* 73 * we always attempt to use the syscall unless we had to 74 * use the clockctl device before 75 * 76 * ntp_adjtime() is callable for mortals if tp->modes == 0 ! 77 */ 78 if (__clockctl_fd == -1) { 79 q = __syscall((quad_t)SYS_ntp_adjtime, tp); 80 if (/* LINTED constant */ sizeof (quad_t) == sizeof (register_t) 81 || /* LINTED constant */ BYTE_ORDER == LITTLE_ENDIAN) 82 rv = (int)q; 83 else 84 rv = (int)((u_quad_t)q >> 32); 85 86 /* 87 * if we fail with EPERM we try the clockctl device 88 */ 89 if (rv != -1 || errno != EPERM) 90 return rv; 91 92 /* 93 * If this fails, it means that we are not root 94 * and we cannot open clockctl. This is a true 95 * failure. 96 */ 97 __clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY, 0); 98 if (__clockctl_fd == -1) { 99 /* original error was EPERM - don't leak open errors */ 100 errno = EPERM; 101 return -1; 102 } 103 104 (void) fcntl(__clockctl_fd, F_SETFD, FD_CLOEXEC); 105 } 106 107 /* 108 * If __clockctl_fd >=0, clockctl has already been open 109 * and used, so we carry on using it. 110 */ 111 args.tp = tp; 112 error = ioctl(__clockctl_fd, CLOCKCTL_NTP_ADJTIME, &args); 113 114 /* 115 * There is no way to get retval set through ioctl(), hence we 116 * have to handle it here, using args.retval 117 */ 118 if (error == 0) { 119 rv = (int)args.retval; 120 return rv; 121 } 122 123 return error; 124 } 125