1*1031c584SApple OSS Distributions /* 2*1031c584SApple OSS Distributions * Copyright (c) 2016 Apple Inc. All rights reserved. 3*1031c584SApple OSS Distributions * 4*1031c584SApple OSS Distributions * @APPLE_LICENSE_HEADER_START@ 5*1031c584SApple OSS Distributions * 6*1031c584SApple OSS Distributions * This file contains Original Code and/or Modifications of Original Code 7*1031c584SApple OSS Distributions * as defined in and that are subject to the Apple Public Source License 8*1031c584SApple OSS Distributions * Version 2.0 (the 'License'). You may not use this file except in 9*1031c584SApple OSS Distributions * compliance with the License. Please obtain a copy of the License at 10*1031c584SApple OSS Distributions * http://www.opensource.apple.com/apsl/ and read it before using this 11*1031c584SApple OSS Distributions * file. 12*1031c584SApple OSS Distributions * 13*1031c584SApple OSS Distributions * The Original Code and all software distributed under the License are 14*1031c584SApple OSS Distributions * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15*1031c584SApple OSS Distributions * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16*1031c584SApple OSS Distributions * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17*1031c584SApple OSS Distributions * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18*1031c584SApple OSS Distributions * Please see the License for the specific language governing rights and 19*1031c584SApple OSS Distributions * limitations under the License. 20*1031c584SApple OSS Distributions * 21*1031c584SApple OSS Distributions * @APPLE_LICENSE_HEADER_END@ 22*1031c584SApple OSS Distributions */ 23*1031c584SApple OSS Distributions #include <mach/mach_time.h> 24*1031c584SApple OSS Distributions 25*1031c584SApple OSS Distributions extern kern_return_t 26*1031c584SApple OSS Distributions mach_timebase_info_trap(mach_timebase_info_t info); 27*1031c584SApple OSS Distributions 28*1031c584SApple OSS Distributions kern_return_t mach_timebase_info(mach_timebase_info_t info)29*1031c584SApple OSS Distributionsmach_timebase_info(mach_timebase_info_t info) 30*1031c584SApple OSS Distributions { 31*1031c584SApple OSS Distributions static mach_timebase_info_data_t cached_info; 32*1031c584SApple OSS Distributions 33*1031c584SApple OSS Distributions /* 34*1031c584SApple OSS Distributions * This is racy, but because it is safe to initialize twice we avoid a 35*1031c584SApple OSS Distributions * barrier in the fast path by risking double initialization. 36*1031c584SApple OSS Distributions */ 37*1031c584SApple OSS Distributions if (cached_info.numer == 0 || cached_info.denom == 0) { 38*1031c584SApple OSS Distributions kern_return_t kr = mach_timebase_info_trap(&cached_info); 39*1031c584SApple OSS Distributions if (kr != KERN_SUCCESS) { 40*1031c584SApple OSS Distributions return kr; 41*1031c584SApple OSS Distributions } 42*1031c584SApple OSS Distributions } 43*1031c584SApple OSS Distributions 44*1031c584SApple OSS Distributions info->numer = cached_info.numer; 45*1031c584SApple OSS Distributions info->denom = cached_info.denom; 46*1031c584SApple OSS Distributions 47*1031c584SApple OSS Distributions return KERN_SUCCESS; 48*1031c584SApple OSS Distributions } 49