softmmu/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-common.h"
  27 #include "qemu/cutils.h"
  28 #include "qapi/error.h"
  29 #include "qapi/qmp/qerror.h"
  30 #include "qemu/error-report.h"
  31 #include "qemu/option.h"
  32 #include "qemu/timer.h"
  33 #include "qom/object.h"
  34 #include "sysemu/replay.h"
  35 #include "sysemu/sysemu.h"
  36
  37 static enum {
  38     RTC_BASE_UTC,
  39     RTC_BASE_LOCALTIME,
  40     RTC_BASE_DATETIME,
  41 } rtc_base_type = RTC_BASE_UTC;
  42 static time_t rtc_ref_start_datetime;
  43 static int rtc_realtime_clock_offset; /* used only with QEMU_CLOCK_REALTIME */
  44 static int rtc_host_datetime_offset = -1; /* valid & used only with
  45                                              RTC_BASE_DATETIME */
  46 QEMUClockType rtc_clock;
  47 /***********************************************************/
  48 /* RTC reference time/date access */
  49 static time_t qemu_ref_timedate(QEMUClockType clock)
  50 {
  51     time_t value = qemu_clock_get_ms(clock) / 1000;
  52     switch (clock) {
  53     case QEMU_CLOCK_REALTIME:
  54         value -= rtc_realtime_clock_offset;
  55         /* fall through */
  56     case QEMU_CLOCK_VIRTUAL:
  57         value += rtc_ref_start_datetime;
  58         break;
  59     case QEMU_CLOCK_HOST:
  60         if (rtc_base_type == RTC_BASE_DATETIME) {
  61             value -= rtc_host_datetime_offset;
  62         }
  63         break;
  64     default:
  65         assert(0);
  66     }
  67     return value;
  68 }
  69
  70 void qemu_get_timedate(struct tm *tm, int offset)
  71 {
  72     time_t ti = qemu_ref_timedate(rtc_clock);
  73
  74     ti += offset;
  75
  76     switch (rtc_base_type) {
  77     case RTC_BASE_DATETIME:
  78     case RTC_BASE_UTC:
  79         gmtime_r(&ti, tm);
  80         break;
  81     case RTC_BASE_LOCALTIME:
  82         localtime_r(&ti, tm);
  83         break;
  84     }
  85 }
  86
  87 int qemu_timedate_diff(struct tm *tm)
  88 {
  89     time_t seconds;
  90
  91     switch (rtc_base_type) {
  92     case RTC_BASE_DATETIME:
  93     case RTC_BASE_UTC:
  94         seconds = mktimegm(tm);
  95         break;
  96     case RTC_BASE_LOCALTIME:
  97     {
  98         struct tm tmp = *tm;
  99         tmp.tm_isdst = -1; /* use timezone to figure it out */
 100         seconds = mktime(&tmp);
 101         break;
 102     }
 103     default:
 104         abort();
 105     }
 106
 107     return seconds - qemu_ref_timedate(QEMU_CLOCK_HOST);
 108 }
 109
 110 static void configure_rtc_base_datetime(const char *startdate)
 111 {
 112     time_t rtc_start_datetime;
 113     struct tm tm;
 114
 115     if (sscanf(startdate, "%d-%d-%dT%d:%d:%d", &tm.tm_year, &tm.tm_mon,
 116                &tm.tm_mday, &tm.tm_hour, &tm.tm_min, &tm.tm_sec) == 6) {
 117         /* OK */
 118     } else if (sscanf(startdate, "%d-%d-%d",
 119                       &tm.tm_year, &tm.tm_mon, &tm.tm_mday) == 3) {
 120         tm.tm_hour = 0;
 121         tm.tm_min = 0;
 122         tm.tm_sec = 0;
 123     } else {
 124         goto date_fail;
 125     }
 126     tm.tm_year -= 1900;
 127     tm.tm_mon--;
 128     rtc_start_datetime = mktimegm(&tm);
 129     if (rtc_start_datetime == -1) {
 130     date_fail:
 131         error_report("invalid datetime format");
 132         error_printf("valid formats: "
 133                      "'2006-06-17T16:01:21' or '2006-06-17'\n");
 134         exit(1);
 135     }
 136     rtc_host_datetime_offset = rtc_ref_start_datetime - rtc_start_datetime;
 137     rtc_ref_start_datetime = rtc_start_datetime;
 138 }
 139
 140 void configure_rtc(QemuOpts *opts)
 141 {
 142     const char *value;
 143
 144     /* Set defaults */
 145     rtc_clock = QEMU_CLOCK_HOST;
 146     rtc_ref_start_datetime = qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
 147     rtc_realtime_clock_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 148
 149     value = qemu_opt_get(opts, "base");
 150     if (value) {
 151         if (!strcmp(value, "utc")) {
 152             rtc_base_type = RTC_BASE_UTC;
 153         } else if (!strcmp(value, "localtime")) {
 154             Error *blocker = NULL;
 155             rtc_base_type = RTC_BASE_LOCALTIME;
 156             error_setg(&blocker, QERR_REPLAY_NOT_SUPPORTED,
 157                       "-rtc base=localtime");
 158             replay_add_blocker(blocker);
 159         } else {
 160             rtc_base_type = RTC_BASE_DATETIME;
 161             configure_rtc_base_datetime(value);
 162         }
 163     }
 164     value = qemu_opt_get(opts, "clock");
 165     if (value) {
 166         if (!strcmp(value, "host")) {
 167             rtc_clock = QEMU_CLOCK_HOST;
 168         } else if (!strcmp(value, "rt")) {
 169             rtc_clock = QEMU_CLOCK_REALTIME;
 170         } else if (!strcmp(value, "vm")) {
 171             rtc_clock = QEMU_CLOCK_VIRTUAL;
 172         } else {
 173             error_report("invalid option value '%s'", value);
 174             exit(1);
 175         }
 176     }
 177     value = qemu_opt_get(opts, "driftfix");
 178     if (value) {
 179         if (!strcmp(value, "slew")) {
 180             object_register_sugar_prop("mc146818rtc",
 181                                        "lost_tick_policy",
 182                                        "slew");
 183         } else if (!strcmp(value, "none")) {
 184             /* discard is default */
 185         } else {
 186             error_report("invalid option value '%s'", value);
 187             exit(1);
 188         }
 189     }
 190 }