1 /* 2 * RTC configuration and clock read 3 * 4 * Copyright (c) 2003-2021 QEMU contributors 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25 #ifndef SYSEMU_RTC_H 26 #define SYSEMU_RTC_H 27 28 /** 29 * qemu_get_timedate: Get the current RTC time 30 * @tm: struct tm to fill in with RTC time 31 * @offset: offset in seconds to adjust the RTC time by before 32 * converting to struct tm format. 33 * 34 * This function fills in @tm with the current RTC time, as adjusted 35 * by @offset (for example, if @offset is 3600 then the returned time/date 36 * will be one hour further ahead than the current RTC time). 37 * 38 * The usual use is by RTC device models, which should call this function 39 * to find the time/date value that they should return to the guest 40 * when it reads the RTC registers. 41 * 42 * The behaviour of the clock whose value this function returns will 43 * depend on the -rtc command line option passed by the user. 44 */ 45 void qemu_get_timedate(struct tm *tm, time_t offset); 46 47 /** 48 * qemu_timedate_diff: Return difference between a struct tm and the RTC 49 * @tm: struct tm containing the date/time to compare against 50 * 51 * Returns the difference in seconds between the RTC clock time 52 * and the date/time specified in @tm. For example, if @tm specifies 53 * a timestamp one hour further ahead than the current RTC time 54 * then this function will return 3600. 55 */ 56 time_t qemu_timedate_diff(struct tm *tm); 57 58 #endif 59