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adjtime.c revision 1.1 
      1 /*	$NetBSD: adjtime.c,v 1.1 2001/09/16 07:41:57 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 #include <fcntl.h>
     36 #include <paths.h>
     37 #include <unistd.h>
     38 #include <time.h>
     39 #include <sys/types.h>
     40 #include <sys/ioctl.h>
     41 #include <sys/syscall.h>
     42 #include <sys/clockctl.h>
     43 
     44 #ifdef __weak_alias
     45 __weak_alias(adjtime,_adjtime)
     46 #endif
     47 
     48 int
     49 adjtime(delta, olddelta)
     50 	const struct timeval *delta;
     51 	struct timeval *olddelta;
     52 {
     53 	struct clockctl_adjtime_args args;
     54 	int error;
     55 	int fd;
     56 	quad_t q;
     57 	int rv;
     58 
     59 	/*
     60 	 * Root always uses the adjtime syscall
     61 	 */
     62 	if (geteuid() == 0)
     63 		goto try_syscall;
     64 
     65 	/*
     66 	 * Try to use /dev/clockctl, and revert to
     67 	 * adjtime syscall if it fails.
     68 	 */
     69 	fd = open(_PATH_CLOCKCTL, O_WRONLY, 0);
     70 	if (fd == -1)
     71 		goto try_syscall;
     72 
     73 	(void)memcpy(&args.delta, delta, sizeof(delta));
     74 	error = ioctl(fd, CLOCKCTL_ADJTIME, &args);
     75 	(void)close(fd);
     76 	if (!error && olddelta) {
     77 		(void)memcpy(olddelta, &args.olddelta, sizeof(olddelta));
     78 		return 0;
     79 	}
     80 
     81 try_syscall:
     82 	q = __syscall((quad_t)SYS_adjtime, delta, olddelta);
     83 	if (/* LINTED constant */ sizeof (quad_t) == sizeof (register_t) ||
     84 		 /* LINTED constant */ BYTE_ORDER == LITTLE_ENDIAN)
     85 		rv = (int)q;
     86 	else
     87 		rv = (int)((u_quad_t)q >> 32);
     88 	return rv;
     89 }
     90