system/rtc.c

   1 /*
   2  * RTC configuration and clock read
   3  *
   4  * Copyright (c) 2003-2020 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 #include "qemu/osdep.h"
  26 #include "qemu/cutils.h"
  27 #include "qapi/error.h"
  28 #include "qapi/qmp/qerror.h"
  29 #include "qemu/error-report.h"
  30 #include "qemu/option.h"
  31 #include "qemu/timer.h"
  32 #include "qom/object.h"
  33 #include "sysemu/replay.h"
  34 #include "sysemu/sysemu.h"
  35 #include "sysemu/rtc.h"
  36 #include "hw/rtc/mc146818rtc.h"
  37
  38 static enum {
  39     RTC_BASE_UTC,
  40     RTC_BASE_LOCALTIME,
  41     RTC_BASE_DATETIME,
  42 } rtc_base_type = RTC_BASE_UTC;
  43 static time_t rtc_ref_start_datetime;
  44 static int rtc_realtime_clock_offset; /* used only with QEMU_CLOCK_REALTIME */
  45 static int rtc_host_datetime_offset = -1; /* valid & used only with
  46                                              RTC_BASE_DATETIME */
  47 QEMUClockType rtc_clock;
  48 /***********************************************************/
  49 /* RTC reference time/date access */
  50 static time_t qemu_ref_timedate(QEMUClockType clock)
  51 {
  52     time_t value = qemu_clock_get_ms(clock) / 1000;
  53     switch (clock) {
  54     case QEMU_CLOCK_REALTIME:
  55         value -= rtc_realtime_clock_offset;
  56         /* fall through */
  57     case QEMU_CLOCK_VIRTUAL:
  58         value += rtc_ref_start_datetime;
  59         break;
  60     case QEMU_CLOCK_HOST:
  61         if (rtc_base_type == RTC_BASE_DATETIME) {
  62             value -= rtc_host_datetime_offset;
  63         }
  64         break;
  65     default:
  66         assert(0);
  67     }
  68     return value;
  69 }
  70
  71 void qemu_get_timedate(struct tm *tm, time_t offset)
  72 {
  73     time_t ti = qemu_ref_timedate(rtc_clock);
  74
  75     ti += offset;
  76
  77     switch (rtc_base_type) {
  78     case RTC_BASE_DATETIME:
  79     case RTC_BASE_UTC:
  80         gmtime_r(&ti, tm);
  81         break;
  82     case RTC_BASE_LOCALTIME:
  83         localtime_r(&ti, tm);
  84         break;
  85     }
  86 }
  87
  88 time_t qemu_timedate_diff(struct tm *tm)
  89 {
  90     time_t seconds;
  91
  92     switch (rtc_base_type) {
  93     case RTC_BASE_DATETIME:
  94     case RTC_BASE_UTC:
  95         seconds = mktimegm(tm);
  96         break;
  97     case RTC_BASE_LOCALTIME:
  98     {
  99         struct tm tmp = *tm;
 100         tmp.tm_isdst = -1; /* use timezone to figure it out */
 101         seconds = mktime(&tmp);
 102         break;
 103     }
 104     default:
 105         abort();
 106     }
 107
 108     return seconds - qemu_ref_timedate(QEMU_CLOCK_HOST);
 109 }
 110
 111 static void configure_rtc_base_datetime(const char *startdate)
 112 {
 113     time_t rtc_start_datetime;
 114     struct tm tm;
 115
 116     if (sscanf(startdate, "%d-%d-%dT%d:%d:%d", &tm.tm_year, &tm.tm_mon,
 117                &tm.tm_mday, &tm.tm_hour, &tm.tm_min, &tm.tm_sec) == 6) {
 118         /* OK */
 119     } else if (sscanf(startdate, "%d-%d-%d",
 120                       &tm.tm_year, &tm.tm_mon, &tm.tm_mday) == 3) {
 121         tm.tm_hour = 0;
 122         tm.tm_min = 0;
 123         tm.tm_sec = 0;
 124     } else {
 125         goto date_fail;
 126     }
 127     tm.tm_year -= 1900;
 128     tm.tm_mon--;
 129     rtc_start_datetime = mktimegm(&tm);
 130     if (rtc_start_datetime == -1) {
 131     date_fail:
 132         error_report("invalid datetime format");
 133         error_printf("valid formats: "
 134                      "'2006-06-17T16:01:21' or '2006-06-17'\n");
 135         exit(1);
 136     }
 137     rtc_host_datetime_offset = rtc_ref_start_datetime - rtc_start_datetime;
 138     rtc_ref_start_datetime = rtc_start_datetime;
 139 }
 140
 141 void configure_rtc(QemuOpts *opts)
 142 {
 143     const char *value;
 144
 145     /* Set defaults */
 146     rtc_clock = QEMU_CLOCK_HOST;
 147     rtc_ref_start_datetime = qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
 148     rtc_realtime_clock_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 149
 150     value = qemu_opt_get(opts, "base");
 151     if (value) {
 152         if (!strcmp(value, "utc")) {
 153             rtc_base_type = RTC_BASE_UTC;
 154         } else if (!strcmp(value, "localtime")) {
 155             rtc_base_type = RTC_BASE_LOCALTIME;
 156             replay_add_blocker("-rtc base=localtime");
 157         } else {
 158             rtc_base_type = RTC_BASE_DATETIME;
 159             configure_rtc_base_datetime(value);
 160         }
 161     }
 162     value = qemu_opt_get(opts, "clock");
 163     if (value) {
 164         if (!strcmp(value, "host")) {
 165             rtc_clock = QEMU_CLOCK_HOST;
 166         } else if (!strcmp(value, "rt")) {
 167             rtc_clock = QEMU_CLOCK_REALTIME;
 168         } else if (!strcmp(value, "vm")) {
 169             rtc_clock = QEMU_CLOCK_VIRTUAL;
 170         } else {
 171             error_report("invalid option value '%s'", value);
 172             exit(1);
 173         }
 174     }
 175     value = qemu_opt_get(opts, "driftfix");
 176     if (value) {
 177         if (!strcmp(value, "slew")) {
 178             object_register_sugar_prop(TYPE_MC146818_RTC,
 179                                        "lost_tick_policy",
 180                                        "slew",
 181                                        false);
 182             if (!object_class_by_name(TYPE_MC146818_RTC)) {
 183                 warn_report("driftfix 'slew' is not available with this machine");
 184             }
 185         } else if (!strcmp(value, "none")) {
 186             /* discard is default */
 187         } else {
 188             error_report("invalid option value '%s'", value);
 189             exit(1);
 190         }
 191     }
 192 }