release/src/router/busybox/util-linux/rtcwake.c

   1 /*
   2  * rtcwake -- enter a system sleep state until specified wakeup time.
   3  *
   4  * This version was taken from util-linux and scrubbed down for busybox.
   5  *
   6  * Licensed under GPLv2, see file LICENSE in this source tree.
   7  *
   8  * This uses cross-platform Linux interfaces to enter a system sleep state,
   9  * and leave it no later than a specified time.  It uses any RTC framework
  10  * driver that supports standard driver model wakeup flags.
  11  *
  12  * This is normally used like the old "apmsleep" utility, to wake from a
  13  * suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM).  Most
  14  * platforms can implement those without analogues of BIOS, APM, or ACPI.
  15  *
  16  * On some systems, this can also be used like "nvram-wakeup", waking
  17  * from states like ACPI S4 (suspend to disk).  Not all systems have
  18  * persistent media that are appropriate for such suspend modes.
  19  *
  20  * The best way to set the system's RTC is so that it holds the current
  21  * time in UTC.  Use the "-l" flag to tell this program that the system
  22  * RTC uses a local timezone instead (maybe you dual-boot MS-Windows).
  23  * That flag should not be needed on systems with adjtime support.
  24  */
  25
  26 //usage:#define rtcwake_trivial_usage
  27 //usage:       "[-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]"
  28 //usage:#define rtcwake_full_usage "\n\n"
  29 //usage:       "Enter a system sleep state until specified wakeup time\n"
  30 //usage:        IF_LONG_OPTS(
  31 //usage:     "\n        -a,--auto       Read clock mode from adjtime"
  32 //usage:     "\n        -l,--local      Clock is set to local time"
  33 //usage:     "\n        -u,--utc        Clock is set to UTC time"
  34 //usage:     "\n        -d,--device=DEV Specify the RTC device"
  35 //usage:     "\n        -m,--mode=MODE  Set the sleep state (default: standby)"
  36 //usage:     "\n        -s,--seconds=SEC Set the timeout in SEC seconds from now"
  37 //usage:     "\n        -t,--time=TIME  Set the timeout to TIME seconds from epoch"
  38 //usage:        )
  39 //usage:        IF_NOT_LONG_OPTS(
  40 //usage:     "\n        -a      Read clock mode from adjtime"
  41 //usage:     "\n        -l      Clock is set to local time"
  42 //usage:     "\n        -u      Clock is set to UTC time"
  43 //usage:     "\n        -d DEV  Specify the RTC device"
  44 //usage:     "\n        -m MODE Set the sleep state (default: standby)"
  45 //usage:     "\n        -s SEC  Set the timeout in SEC seconds from now"
  46 //usage:     "\n        -t TIME Set the timeout to TIME seconds from epoch"
  47 //usage:        )
  48
  49 #include "libbb.h"
  50 #include "rtc_.h"
  51
  52 #define SYS_RTC_PATH   "/sys/class/rtc/%s/device/power/wakeup"
  53 #define SYS_POWER_PATH "/sys/power/state"
  54 #define DEFAULT_MODE   "standby"
  55
  56 static NOINLINE bool may_wakeup(const char *rtcname)
  57 {
  58         ssize_t ret;
  59         char buf[128];
  60
  61         /* strip "/dev/" from the rtcname here */
  62         rtcname = skip_dev_pfx(rtcname);
  63
  64         snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname);
  65         ret = open_read_close(buf, buf, sizeof(buf));
  66         if (ret < 0)
  67                 return false;
  68
  69         /* wakeup events could be disabled or not supported */
  70         return strncmp(buf, "enabled\n", 8) == 0;
  71 }
  72
  73 static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time)
  74 {
  75         struct tm *ptm;
  76         struct linux_rtc_wkalrm wake;
  77
  78         /* The wakeup time is in POSIX time (more or less UTC).
  79          * Ideally RTCs use that same time; but PCs can't do that
  80          * if they need to boot MS-Windows.  Messy...
  81          *
  82          * When running in utc mode this process's timezone is UTC,
  83          * so we'll pass a UTC date to the RTC.
  84          *
  85          * Else mode is local so the time given to the RTC
  86          * will instead use the local time zone.
  87          */
  88         ptm = localtime(wakeup);
  89
  90         wake.time.tm_sec = ptm->tm_sec;
  91         wake.time.tm_min = ptm->tm_min;
  92         wake.time.tm_hour = ptm->tm_hour;
  93         wake.time.tm_mday = ptm->tm_mday;
  94         wake.time.tm_mon = ptm->tm_mon;
  95         wake.time.tm_year = ptm->tm_year;
  96         /* wday, yday, and isdst fields are unused by Linux */
  97         wake.time.tm_wday = -1;
  98         wake.time.tm_yday = -1;
  99         wake.time.tm_isdst = -1;
 100
 101         /* many rtc alarms only support up to 24 hours from 'now',
 102          * so use the "more than 24 hours" request only if we must
 103          */
 104         if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
 105                 xioctl(fd, RTC_ALM_SET, &wake.time);
 106                 xioctl(fd, RTC_AIE_ON, 0);
 107         } else {
 108                 /* avoid an extra AIE_ON call */
 109                 wake.enabled = 1;
 110                 xioctl(fd, RTC_WKALM_SET, &wake);
 111         }
 112 }
 113
 114 #define RTCWAKE_OPT_AUTO         0x01
 115 #define RTCWAKE_OPT_LOCAL        0x02
 116 #define RTCWAKE_OPT_UTC          0x04
 117 #define RTCWAKE_OPT_DEVICE       0x08
 118 #define RTCWAKE_OPT_SUSPEND_MODE 0x10
 119 #define RTCWAKE_OPT_SECONDS      0x20
 120 #define RTCWAKE_OPT_TIME         0x40
 121
 122 int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 123 int rtcwake_main(int argc UNUSED_PARAM, char **argv)
 124 {
 125         time_t rtc_time;
 126
 127         unsigned opt;
 128         const char *rtcname = NULL;
 129         const char *suspend;
 130         const char *opt_seconds;
 131         const char *opt_time;
 132
 133         time_t sys_time;
 134         time_t alarm_time = 0;
 135         unsigned seconds = 0;
 136         int utc = -1;
 137         int fd;
 138
 139 #if ENABLE_LONG_OPTS
 140         static const char rtcwake_longopts[] ALIGN1 =
 141                 "auto\0"    No_argument "a"
 142                 "local\0"   No_argument "l"
 143                 "utc\0"     No_argument "u"
 144                 "device\0"  Required_argument "d"
 145                 "mode\0"    Required_argument "m"
 146                 "seconds\0" Required_argument "s"
 147                 "time\0"    Required_argument "t"
 148                 ;
 149         applet_long_options = rtcwake_longopts;
 150 #endif
 151         opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time);
 152
 153         /* this is the default
 154         if (opt & RTCWAKE_OPT_AUTO)
 155                 utc = -1;
 156         */
 157         if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL))
 158                 utc = opt & RTCWAKE_OPT_UTC;
 159         if (!(opt & RTCWAKE_OPT_SUSPEND_MODE))
 160                 suspend = DEFAULT_MODE;
 161         if (opt & RTCWAKE_OPT_SECONDS)
 162                 /* alarm time, seconds-to-sleep (relative) */
 163                 seconds = xatoi(opt_seconds);
 164         if (opt & RTCWAKE_OPT_TIME)
 165                 /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
 166                 alarm_time = xatol(opt_time);
 167
 168         if (!alarm_time && !seconds)
 169                 bb_error_msg_and_die("must provide wake time");
 170
 171         if (utc == -1)
 172                 utc = rtc_adjtime_is_utc();
 173
 174         /* the rtcname is relative to /dev */
 175         xchdir("/dev");
 176
 177         /* this RTC must exist and (if we'll sleep) be wakeup-enabled */
 178         fd = rtc_xopen(&rtcname, O_RDONLY);
 179
 180         if (strcmp(suspend, "on") && !may_wakeup(rtcname))
 181                 bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
 182
 183         /* relative or absolute alarm time, normalized to time_t */
 184         sys_time = time(NULL);
 185         {
 186                 struct tm tm_time;
 187                 rtc_read_tm(&tm_time, fd);
 188                 rtc_time = rtc_tm2time(&tm_time, utc);
 189         }
 190
 191
 192         if (alarm_time) {
 193                 if (alarm_time < sys_time)
 194                         bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time));
 195                 alarm_time += sys_time - rtc_time;
 196         } else
 197                 alarm_time = rtc_time + seconds + 1;
 198         setup_alarm(fd, &alarm_time, rtc_time);
 199
 200         sync();
 201         printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time));
 202         fflush_all();
 203         usleep(10 * 1000);
 204
 205         if (strcmp(suspend, "on"))
 206                 xopen_xwrite_close(SYS_POWER_PATH, suspend);
 207         else {
 208                 /* "fake" suspend ... we'll do the delay ourselves */
 209                 unsigned long data;
 210
 211                 do {
 212                         ssize_t ret = safe_read(fd, &data, sizeof(data));
 213                         if (ret < 0) {
 214                                 bb_perror_msg("rtc read");
 215                                 break;
 216                         }
 217                 } while (!(data & RTC_AF));
 218         }
 219
 220         xioctl(fd, RTC_AIE_OFF, 0);
 221
 222         if (ENABLE_FEATURE_CLEAN_UP)
 223                 close(fd);
 224
 225         return EXIT_SUCCESS;
 226 }