NetBSD/lib/libc/sys/adjtime.c

122 lines
3.7 KiB
C

/* $NetBSD: adjtime.c,v 1.3 2001/12/09 16:11:45 manu Exp $ */
/*
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Emmanuel Dreyfus.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "namespace.h"
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <sys/systm.h>
#include <sys/clockctl.h>
#ifdef __weak_alias
__weak_alias(adjtime,_adjtime)
#endif
extern int __clockctl_fd;
int
adjtime(delta, olddelta)
const struct timeval *delta;
struct timeval *olddelta;
{
struct sys_adjtime_args args;
int error;
quad_t q;
int rv;
/*
* if __clockctl_fd == -1, then this is not our first time,
* and we know root is the calling user. We use the system call
*/
if (__clockctl_fd == -1) {
try_syscall:
q = __syscall((quad_t)SYS_adjtime, delta, olddelta);
if (/* LINTED constant */ sizeof (quad_t) == sizeof (register_t)
|| /* LINTED constant */ BYTE_ORDER == LITTLE_ENDIAN)
rv = (int)q;
else
rv = (int)((u_quad_t)q >> 32);
/*
* If credentials changed from root to an unprivilegied
* user, and we already had __clockctl_fd = -1, then we
* tried the system call as a non root user, it failed
* with EPERM, and we will try clockctl.
*/
if (rv != -1 || errno != EPERM)
return rv;
__clockctl_fd = -2;
}
/*
* If __clockctl_fd = -2 then this is our first time here,
* or credentials have changed (the calling process dropped root
* root privilege). Check if root is the calling user. If it is,
* we try the system call, if it is not, we try clockctl.
*/
if (__clockctl_fd == -2) {
/*
* Root always uses the syscall
*/
if (geteuid() == 0) {
__clockctl_fd = -1;
goto try_syscall;
}
/*
* If this fails, it means that we are not root
* and we cannot open clockctl. This is a failure.
*/
__clockctl_fd = open(_PATH_CLOCKCTL, O_WRONLY, 0);
if (__clockctl_fd == -1)
return -1;
}
/*
* If __clockctl_fd >=0, clockctl has already been open
* and used, so we carry on using it.
*/
SCARG(&args, delta) = delta;
SCARG(&args, olddelta) = olddelta;
error = ioctl(__clockctl_fd, CLOCKCTL_ADJTIME, &args);
return error;
}