diff options
Diffstat (limited to 'util-linux/rtcwake.c')
| -rw-r--r-- | util-linux/rtcwake.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/util-linux/rtcwake.c b/util-linux/rtcwake.c new file mode 100644 index 0000000..a9766ca --- /dev/null +++ b/util-linux/rtcwake.c @@ -0,0 +1,199 @@ +/* + * rtcwake -- enter a system sleep state until specified wakeup time. + * + * This version was taken from util-linux and scrubbed down for busybox. + * + * This uses cross-platform Linux interfaces to enter a system sleep state, + * and leave it no later than a specified time. It uses any RTC framework + * driver that supports standard driver model wakeup flags. + * + * This is normally used like the old "apmsleep" utility, to wake from a + * suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM). Most + * platforms can implement those without analogues of BIOS, APM, or ACPI. + * + * On some systems, this can also be used like "nvram-wakeup", waking + * from states like ACPI S4 (suspend to disk). Not all systems have + * persistent media that are appropriate for such suspend modes. + * + * The best way to set the system's RTC is so that it holds the current + * time in UTC. Use the "-l" flag to tell this program that the system + * RTC uses a local timezone instead (maybe you dual-boot MS-Windows). + * That flag should not be needed on systems with adjtime support. + */ + +#include "libbb.h" +#include "rtc_.h" + +#define SYS_RTC_PATH "/sys/class/rtc/%s/device/power/wakeup" +#define SYS_POWER_PATH "/sys/power/state" +#define DEFAULT_MODE "standby" + +static time_t rtc_time; + +static bool may_wakeup(const char *rtcname) +{ + ssize_t ret; + char buf[128]; + + /* strip the '/dev/' from the rtcname here */ + if (!strncmp(rtcname, "/dev/", 5)) + rtcname += 5; + + snprintf(buf, sizeof(buf), SYS_RTC_PATH, rtcname); + ret = open_read_close(buf, buf, sizeof(buf)); + if (ret < 0) + return false; + + /* wakeup events could be disabled or not supported */ + return strncmp(buf, "enabled\n", 8) == 0; +} + +static void setup_alarm(int fd, time_t *wakeup) +{ + struct tm *tm; + struct linux_rtc_wkalrm wake; + + /* The wakeup time is in POSIX time (more or less UTC). + * Ideally RTCs use that same time; but PCs can't do that + * if they need to boot MS-Windows. Messy... + * + * When running in utc mode this process's timezone is UTC, + * so we'll pass a UTC date to the RTC. + * + * Else mode is local so the time given to the RTC + * will instead use the local time zone. + */ + tm = localtime(wakeup); + + wake.time.tm_sec = tm->tm_sec; + wake.time.tm_min = tm->tm_min; + wake.time.tm_hour = tm->tm_hour; + wake.time.tm_mday = tm->tm_mday; + wake.time.tm_mon = tm->tm_mon; + wake.time.tm_year = tm->tm_year; + /* wday, yday, and isdst fields are unused by Linux */ + wake.time.tm_wday = -1; + wake.time.tm_yday = -1; + wake.time.tm_isdst = -1; + + /* many rtc alarms only support up to 24 hours from 'now', + * so use the "more than 24 hours" request only if we must + */ + if ((rtc_time + (24 * 60 * 60)) > *wakeup) { + xioctl(fd, RTC_ALM_SET, &wake.time); + xioctl(fd, RTC_AIE_ON, 0); + } else { + /* avoid an extra AIE_ON call */ + wake.enabled = 1; + xioctl(fd, RTC_WKALM_SET, &wake); + } +} + +#define RTCWAKE_OPT_AUTO 0x01 +#define RTCWAKE_OPT_LOCAL 0x02 +#define RTCWAKE_OPT_UTC 0x04 +#define RTCWAKE_OPT_DEVICE 0x08 +#define RTCWAKE_OPT_SUSPEND_MODE 0x10 +#define RTCWAKE_OPT_SECONDS 0x20 +#define RTCWAKE_OPT_TIME 0x40 + +int rtcwake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int rtcwake_main(int argc UNUSED_PARAM, char **argv) +{ + unsigned opt; + const char *rtcname = NULL; + const char *suspend; + const char *opt_seconds; + const char *opt_time; + + time_t sys_time; + time_t alarm_time = 0; + unsigned seconds = 0; + int utc = -1; + int fd; + +#if ENABLE_GETOPT_LONG + static const char rtcwake_longopts[] ALIGN1 = + "auto\0" No_argument "a" + "local\0" No_argument "l" + "utc\0" No_argument "u" + "device\0" Required_argument "d" + "mode\0" Required_argument "m" + "seconds\0" Required_argument "s" + "time\0" Required_argument "t" + ; + applet_long_options = rtcwake_longopts; +#endif + opt = getopt32(argv, "alud:m:s:t:", &rtcname, &suspend, &opt_seconds, &opt_time); + + /* this is the default + if (opt & RTCWAKE_OPT_AUTO) + utc = -1; + */ + if (opt & (RTCWAKE_OPT_UTC | RTCWAKE_OPT_LOCAL)) + utc = opt & RTCWAKE_OPT_UTC; + if (!(opt & RTCWAKE_OPT_SUSPEND_MODE)) + suspend = DEFAULT_MODE; + if (opt & RTCWAKE_OPT_SECONDS) + /* alarm time, seconds-to-sleep (relative) */ + seconds = xatoi(opt_seconds); + if (opt & RTCWAKE_OPT_TIME) + /* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */ + alarm_time = xatoi(opt_time); + + if (!alarm_time && !seconds) + bb_error_msg_and_die("must provide wake time"); + + if (utc == -1) + utc = rtc_adjtime_is_utc(); + + /* the rtcname is relative to /dev */ + xchdir("/dev"); + + /* this RTC must exist and (if we'll sleep) be wakeup-enabled */ + fd = rtc_xopen(&rtcname, O_RDONLY); + + if (strcmp(suspend, "on") && !may_wakeup(rtcname)) + bb_error_msg_and_die("%s not enabled for wakeup events", rtcname); + + /* relative or absolute alarm time, normalized to time_t */ + sys_time = time(0); + if (sys_time == (time_t)-1) + bb_perror_msg_and_die("read system time"); + rtc_time = rtc_read_time(fd, utc); + + if (alarm_time) { + if (alarm_time < sys_time) + bb_error_msg_and_die("time doesn't go backward to %s", ctime(&alarm_time)); + alarm_time += sys_time - rtc_time; + } else + alarm_time = rtc_time + seconds + 1; + setup_alarm(fd, &alarm_time); + + sync(); + printf("wakeup from \"%s\" at %s", suspend, ctime(&alarm_time)); + fflush(stdout); + usleep(10 * 1000); + + if (strcmp(suspend, "on")) + xopen_xwrite_close(SYS_POWER_PATH, suspend); + else { + /* "fake" suspend ... we'll do the delay ourselves */ + unsigned long data; + + do { + ssize_t ret = safe_read(fd, &data, sizeof(data)); + if (ret < 0) { + bb_perror_msg("rtc read"); + break; + } + } while (!(data & RTC_AF)); + } + + xioctl(fd, RTC_AIE_OFF, 0); + + if (ENABLE_FEATURE_CLEAN_UP) + close(fd); + + return EXIT_SUCCESS; +} |