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