rtcwake.c 7.1 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235
  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. //usage:#define rtcwake_trivial_usage
  26. //usage: "[-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]"
  27. //usage:#define rtcwake_full_usage "\n\n"
  28. //usage: "Enter a system sleep state until specified wakeup time\n"
  29. //usage: IF_LONG_OPTS(
  30. //usage: "\n -a,--auto Read clock mode from adjtime"
  31. //usage: "\n -l,--local Clock is set to local time"
  32. //usage: "\n -u,--utc Clock is set to UTC time"
  33. //usage: "\n -d,--device=DEV Specify the RTC device"
  34. //usage: "\n -m,--mode=MODE Set sleep state (default: standby)"
  35. //usage: "\n -s,--seconds=SEC Set timeout in SEC seconds from now"
  36. //usage: "\n -t,--time=TIME Set timeout to TIME seconds from epoch"
  37. //usage: )
  38. //usage: IF_NOT_LONG_OPTS(
  39. //usage: "\n -a Read clock mode from adjtime"
  40. //usage: "\n -l Clock is set to local time"
  41. //usage: "\n -u Clock is set to UTC time"
  42. //usage: "\n -d DEV Specify the RTC device"
  43. //usage: "\n -m MODE Set sleep state (default: standby)"
  44. //usage: "\n -s SEC Set timeout in SEC seconds from now"
  45. //usage: "\n -t TIME Set timeout to TIME seconds from epoch"
  46. //usage: )
  47. #include "libbb.h"
  48. #include "rtc_.h"
  49. #define SYS_RTC_PATH "/sys/class/rtc/%s/device/power/wakeup"
  50. #define SYS_POWER_PATH "/sys/power/state"
  51. static NOINLINE bool may_wakeup(const char *rtcname)
  52. {
  53. ssize_t ret;
  54. char buf[128];
  55. /* strip "/dev/" from the rtcname here */
  56. rtcname = skip_dev_pfx(rtcname);
  57. snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname);
  58. ret = open_read_close(buf, buf, sizeof(buf));
  59. if (ret < 0)
  60. return false;
  61. /* wakeup events could be disabled or not supported */
  62. return is_prefixed_with(buf, "enabled\n") != NULL;
  63. }
  64. static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time)
  65. {
  66. struct tm *ptm;
  67. struct linux_rtc_wkalrm wake;
  68. /* The wakeup time is in POSIX time (more or less UTC).
  69. * Ideally RTCs use that same time; but PCs can't do that
  70. * if they need to boot MS-Windows. Messy...
  71. *
  72. * When running in utc mode this process's timezone is UTC,
  73. * so we'll pass a UTC date to the RTC.
  74. *
  75. * Else mode is local so the time given to the RTC
  76. * will instead use the local time zone.
  77. */
  78. ptm = localtime(wakeup);
  79. wake.time.tm_sec = ptm->tm_sec;
  80. wake.time.tm_min = ptm->tm_min;
  81. wake.time.tm_hour = ptm->tm_hour;
  82. wake.time.tm_mday = ptm->tm_mday;
  83. wake.time.tm_mon = ptm->tm_mon;
  84. wake.time.tm_year = ptm->tm_year;
  85. /* wday, yday, and isdst fields are unused by Linux */
  86. wake.time.tm_wday = -1;
  87. wake.time.tm_yday = -1;
  88. wake.time.tm_isdst = -1;
  89. /* many rtc alarms only support up to 24 hours from 'now',
  90. * so use the "more than 24 hours" request only if we must
  91. */
  92. if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
  93. xioctl(fd, RTC_ALM_SET, &wake.time);
  94. xioctl(fd, RTC_AIE_ON, 0);
  95. } else {
  96. /* avoid an extra AIE_ON call */
  97. wake.enabled = 1;
  98. xioctl(fd, RTC_WKALM_SET, &wake);
  99. }
  100. }
  101. #define RTCWAKE_OPT_AUTO 0x01
  102. #define RTCWAKE_OPT_LOCAL 0x02
  103. #define RTCWAKE_OPT_UTC 0x04
  104. #define RTCWAKE_OPT_DEVICE 0x08
  105. #define RTCWAKE_OPT_SUSPEND_MODE 0x10
  106. #define RTCWAKE_OPT_SECONDS 0x20
  107. #define RTCWAKE_OPT_TIME 0x40
  108. int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  109. int rtcwake_main(int argc UNUSED_PARAM, char **argv)
  110. {
  111. unsigned opt;
  112. const char *rtcname = NULL;
  113. const char *suspend = "standby";
  114. const char *opt_seconds;
  115. const char *opt_time;
  116. time_t rtc_time;
  117. time_t sys_time;
  118. time_t alarm_time = alarm_time;
  119. unsigned seconds = seconds; /* for compiler */
  120. int utc = -1;
  121. int fd;
  122. #if ENABLE_LONG_OPTS
  123. static const char rtcwake_longopts[] ALIGN1 =
  124. "auto\0" No_argument "a"
  125. "local\0" No_argument "l"
  126. "utc\0" No_argument "u"
  127. "device\0" Required_argument "d"
  128. "mode\0" Required_argument "m"
  129. "seconds\0" Required_argument "s"
  130. "time\0" Required_argument "t"
  131. ;
  132. applet_long_options = rtcwake_longopts;
  133. #endif
  134. /* Must have -s or -t, exclusive */
  135. opt_complementary = "s:t:s--t:t--s";
  136. opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time);
  137. /* this is the default
  138. if (opt & RTCWAKE_OPT_AUTO)
  139. utc = -1;
  140. */
  141. if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL))
  142. utc = opt & RTCWAKE_OPT_UTC;
  143. if (opt & RTCWAKE_OPT_SECONDS) {
  144. /* alarm time, seconds-to-sleep (relative) */
  145. seconds = xatou(opt_seconds);
  146. } else {
  147. /* RTCWAKE_OPT_TIME */
  148. /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
  149. if (sizeof(alarm_time) <= sizeof(long))
  150. alarm_time = xatol(opt_time);
  151. else
  152. alarm_time = xatoll(opt_time);
  153. }
  154. if (utc == -1)
  155. utc = rtc_adjtime_is_utc();
  156. /* the rtcname is relative to /dev */
  157. xchdir("/dev");
  158. /* this RTC must exist and (if we'll sleep) be wakeup-enabled */
  159. fd = rtc_xopen(&rtcname, O_RDONLY);
  160. if (strcmp(suspend, "on") != 0)
  161. if (!may_wakeup(rtcname))
  162. bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
  163. /* relative or absolute alarm time, normalized to time_t */
  164. sys_time = time(NULL);
  165. {
  166. struct tm tm_time;
  167. rtc_read_tm(&tm_time, fd);
  168. rtc_time = rtc_tm2time(&tm_time, utc);
  169. }
  170. if (opt & RTCWAKE_OPT_TIME) {
  171. /* Correct for RTC<->system clock difference */
  172. alarm_time += rtc_time - sys_time;
  173. if (alarm_time < rtc_time)
  174. /*
  175. * Compat message text.
  176. * I'd say "RTC time is already ahead of ..." instead.
  177. */
  178. bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time));
  179. } else
  180. alarm_time = rtc_time + seconds + 1;
  181. setup_alarm(fd, &alarm_time, rtc_time);
  182. sync();
  183. #if 0 /*debug*/
  184. printf("sys_time: %s", ctime(&sys_time));
  185. printf("rtc_time: %s", ctime(&rtc_time));
  186. #endif
  187. printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time));
  188. fflush_all();
  189. usleep(10 * 1000);
  190. if (strcmp(suspend, "on") != 0)
  191. xopen_xwrite_close(SYS_POWER_PATH, suspend);
  192. else {
  193. /* "fake" suspend ... we'll do the delay ourselves */
  194. unsigned long data;
  195. do {
  196. ssize_t ret = safe_read(fd, &data, sizeof(data));
  197. if (ret < 0) {
  198. bb_perror_msg("rtc read");
  199. break;
  200. }
  201. } while (!(data & RTC_AF));
  202. }
  203. xioctl(fd, RTC_AIE_OFF, 0);
  204. if (ENABLE_FEATURE_CLEAN_UP)
  205. close(fd);
  206. return EXIT_SUCCESS;
  207. }