234 lines
6.8 KiB
C
234 lines
6.8 KiB
C
/*
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* rtcwake -- enter a system sleep state until specified wakeup time.
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*
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* This version was taken from util-linux and scrubbed down for busybox.
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*
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* Licensed under GPLv2, see file LICENSE in this source tree.
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*
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* This uses cross-platform Linux interfaces to enter a system sleep state,
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* and leave it no later than a specified time. It uses any RTC framework
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* driver that supports standard driver model wakeup flags.
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*
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* This is normally used like the old "apmsleep" utility, to wake from a
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* suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM). Most
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* platforms can implement those without analogues of BIOS, APM, or ACPI.
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*
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* On some systems, this can also be used like "nvram-wakeup", waking
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* from states like ACPI S4 (suspend to disk). Not all systems have
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* persistent media that are appropriate for such suspend modes.
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*
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* The best way to set the system's RTC is so that it holds the current
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* time in UTC. Use the "-l" flag to tell this program that the system
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* RTC uses a local timezone instead (maybe you dual-boot MS-Windows).
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* That flag should not be needed on systems with adjtime support.
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*/
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//config:config RTCWAKE
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//config: bool "rtcwake (6.8 kb)"
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//config: default y
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//config: help
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//config: Enter a system sleep state until specified wakeup time.
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//applet:IF_RTCWAKE(APPLET(rtcwake, BB_DIR_USR_SBIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_RTCWAKE) += rtcwake.o
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//usage:#define rtcwake_trivial_usage
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//usage: "[-a | -l | -u] [-d DEV] [-m MODE] [-s SEC | -t TIME]"
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//usage:#define rtcwake_full_usage "\n\n"
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//usage: "Enter a system sleep state until specified wakeup time\n"
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//usage: "\n -a Read clock mode from "ADJTIME_PATH" (default)"
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//usage: "\n -l Clock is set to local time"
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//usage: "\n -u Clock is set to UTC time"
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//usage: "\n -d DEV Specify the RTC device"
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//usage: "\n -m MODE Set sleep state (default: standby)"
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//usage: "\n -s SEC Set timeout in SEC seconds from now"
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//usage: "\n -t TIME Set timeout to TIME seconds from epoch"
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#include "libbb.h"
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#include "rtc_.h"
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#define SYS_RTC_PATH "/sys/class/rtc/%s/device/power/wakeup"
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#define SYS_POWER_PATH "/sys/power/state"
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static NOINLINE bool may_wakeup(const char *rtcname)
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{
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ssize_t ret;
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char buf[128];
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/* strip "/dev/" from the rtcname here */
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rtcname = skip_dev_pfx(rtcname);
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snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname);
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ret = open_read_close(buf, buf, sizeof(buf));
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if (ret < 0)
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return false;
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/* wakeup events could be disabled or not supported */
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return is_prefixed_with(buf, "enabled\n") != NULL;
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}
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static NOINLINE void setup_alarm(int fd, time_t *wakeup, time_t rtc_time)
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{
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struct tm *ptm;
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struct linux_rtc_wkalrm wake;
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/* The wakeup time is in POSIX time (more or less UTC).
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* Ideally RTCs use that same time; but PCs can't do that
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* if they need to boot MS-Windows. Messy...
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*
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* When running in utc mode this process's timezone is UTC,
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* so we'll pass a UTC date to the RTC.
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*
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* Else mode is local so the time given to the RTC
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* will instead use the local time zone.
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*/
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ptm = localtime(wakeup);
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wake.time.tm_sec = ptm->tm_sec;
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wake.time.tm_min = ptm->tm_min;
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wake.time.tm_hour = ptm->tm_hour;
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wake.time.tm_mday = ptm->tm_mday;
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wake.time.tm_mon = ptm->tm_mon;
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wake.time.tm_year = ptm->tm_year;
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/* wday, yday, and isdst fields are unused by Linux */
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wake.time.tm_wday = -1;
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wake.time.tm_yday = -1;
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wake.time.tm_isdst = -1;
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/* many rtc alarms only support up to 24 hours from 'now',
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* so use the "more than 24 hours" request only if we must
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*/
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if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
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xioctl(fd, RTC_ALM_SET, &wake.time);
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xioctl(fd, RTC_AIE_ON, 0);
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} else {
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/* avoid an extra AIE_ON call */
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wake.enabled = 1;
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xioctl(fd, RTC_WKALM_SET, &wake);
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}
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}
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#define RTCWAKE_OPT_AUTO 0x01
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#define RTCWAKE_OPT_LOCAL 0x02
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#define RTCWAKE_OPT_UTC 0x04
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#define RTCWAKE_OPT_DEVICE 0x08
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#define RTCWAKE_OPT_SUSPEND_MODE 0x10
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#define RTCWAKE_OPT_SECONDS 0x20
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#define RTCWAKE_OPT_TIME 0x40
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int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int rtcwake_main(int argc UNUSED_PARAM, char **argv)
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{
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unsigned opt;
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const char *rtcname = NULL;
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const char *suspend = "standby";
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const char *opt_seconds;
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const char *opt_time;
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time_t rtc_time;
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time_t sys_time;
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time_t alarm_time = alarm_time;
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unsigned seconds = seconds; /* for compiler */
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int utc = -1;
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int fd;
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#if ENABLE_LONG_OPTS
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static const char rtcwake_longopts[] ALIGN1 =
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"auto\0" No_argument "a"
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"local\0" No_argument "l"
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"utc\0" No_argument "u"
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"device\0" Required_argument "d"
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"mode\0" Required_argument "m"
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"seconds\0" Required_argument "s"
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"time\0" Required_argument "t"
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;
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#endif
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opt = getopt32long(argv,
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/* Must have -s or -t, exclusive */
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"^alud:m:s:t:" "\0" "s:t:s--t:t--s", rtcwake_longopts,
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&rtcname, &suspend, &opt_seconds, &opt_time);
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/* this is the default
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if (opt & RTCWAKE_OPT_AUTO)
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utc = -1;
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*/
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if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL))
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utc = opt & RTCWAKE_OPT_UTC;
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if (opt & RTCWAKE_OPT_SECONDS) {
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/* alarm time, seconds-to-sleep (relative) */
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seconds = xatou(opt_seconds);
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} else {
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/* RTCWAKE_OPT_TIME */
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/* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
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if (sizeof(alarm_time) <= sizeof(long))
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alarm_time = xatol(opt_time);
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else
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alarm_time = xatoll(opt_time);
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}
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if (utc == -1)
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utc = rtc_adjtime_is_utc();
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/* the rtcname is relative to /dev */
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xchdir("/dev");
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/* this RTC must exist and (if we'll sleep) be wakeup-enabled */
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fd = rtc_xopen(&rtcname, O_RDONLY);
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if (strcmp(suspend, "on") != 0)
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if (!may_wakeup(rtcname))
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bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
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/* relative or absolute alarm time, normalized to time_t */
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sys_time = time(NULL);
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{
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struct tm tm_time;
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rtc_read_tm(&tm_time, fd);
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rtc_time = rtc_tm2time(&tm_time, utc);
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}
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if (opt & RTCWAKE_OPT_TIME) {
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/* Correct for RTC<->system clock difference */
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alarm_time += rtc_time - sys_time;
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if (alarm_time < rtc_time)
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/*
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* Compat message text.
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* I'd say "RTC time is already ahead of ..." instead.
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*/
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bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time));
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} else
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alarm_time = rtc_time + seconds + 1;
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setup_alarm(fd, &alarm_time, rtc_time);
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sync();
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#if 0 /*debug*/
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printf("sys_time: %s", ctime(&sys_time));
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printf("rtc_time: %s", ctime(&rtc_time));
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#endif
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printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time));
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fflush_all();
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usleep(10 * 1000);
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if (strcmp(suspend, "on") != 0)
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xopen_xwrite_close(SYS_POWER_PATH, suspend);
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else {
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/* "fake" suspend ... we'll do the delay ourselves */
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unsigned long data;
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do {
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ssize_t ret = safe_read(fd, &data, sizeof(data));
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if (ret < 0) {
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bb_simple_perror_msg("rtc read");
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break;
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}
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} while (!(data & RTC_AF));
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}
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xioctl(fd, RTC_AIE_OFF, 0);
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if (ENABLE_FEATURE_CLEAN_UP)
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close(fd);
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return EXIT_SUCCESS;
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}
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