split some rtc funcs out of hwclock and into an rtc header/lib so that the new rtcwake applet as well as hwclock can utilize the same code

4 files changed, 232 insertions, 99 deletions

diff --git a/util-linux/Config.in b/util-linux/Config.in
index e97f840..d1688e8 100644
--- a/util-linux/Config.in
+++ b/util-linux/Config.in
@@ -458,6 +458,12 @@ config READPROFILE
 	help
 	  This allows you to parse /proc/profile for basic profiling.
 
+config RTCWAKE
+	bool "rtcwake"
+	default n
+	help
+	  Enter a system sleep state until specified wakeup time.
+
 config SETARCH
 	bool "setarch"
 	default n
diff --git a/util-linux/Kbuild b/util-linux/Kbuild
index cc1d0e0..4a18ff2 100644
--- a/util-linux/Kbuild
+++ b/util-linux/Kbuild
@@ -26,6 +26,7 @@ lib-$(CONFIG_MOUNT)		+=mount.o
 lib-$(CONFIG_PIVOT_ROOT)	+=pivot_root.o
 lib-$(CONFIG_RDATE)		+=rdate.o
 lib-$(CONFIG_READPROFILE)	+=readprofile.o
+lib-$(CONFIG_RTCWAKE)		+=rtcwake.o
 lib-$(CONFIG_SETARCH)		+=setarch.o
 lib-$(CONFIG_SWAPONOFF)		+=swaponoff.o
 lib-$(CONFIG_SWITCH_ROOT)	+=switch_root.o
diff --git a/util-linux/hwclock.c b/util-linux/hwclock.c
index f91379b..b581d26 100644
--- a/util-linux/hwclock.c
+++ b/util-linux/hwclock.c
@@ -10,22 +10,7 @@
 #include <sys/utsname.h>
 #include <getopt.h>
 #include "libbb.h"
-
-/* Copied from linux/rtc.h to eliminate the kernel dependency */
-struct linux_rtc_time {
-	int tm_sec;
-	int tm_min;
-	int tm_hour;
-	int tm_mday;
-	int tm_mon;
-	int tm_year;
-	int tm_wday;
-	int tm_yday;
-	int tm_isdst;
-};
-
-#define RTC_SET_TIME   _IOW('p', 0x0a, struct linux_rtc_time) /* Set RTC time    */
-#define RTC_RD_TIME    _IOR('p', 0x09, struct linux_rtc_time) /* Read RTC time   */
+#include "rtc_.h"
 
 #if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
 # ifndef _GNU_SOURCE
@@ -35,56 +20,22 @@ struct linux_rtc_time {
 
 static const char *rtcname;
 
-static int xopen_rtc(int flags)
-{
-	int rtc;
-
-	if (!rtcname) {
-		rtc = open("/dev/rtc", flags);
-		if (rtc >= 0)
-			return rtc;
-		rtc = open("/dev/rtc0", flags);
-		if (rtc >= 0)
-			return rtc;
-		rtcname = "/dev/misc/rtc";
-	}
-	return xopen(rtcname, flags);
-}
-
 static time_t read_rtc(int utc)
 {
-	struct tm tm;
-	char *oldtz = 0;
-	time_t t = 0;
-	int rtc = xopen_rtc(O_RDONLY);
+	time_t ret;
+	int fd;
 
-	memset(&tm, 0, sizeof(struct tm));
-	xioctl(rtc, RTC_RD_TIME, &tm);
-	tm.tm_isdst = -1; /* not known */
+	fd = rtc_xopen(rtcname, O_RDONLY);
+	ret = rtc_read_time(fd, utc);
+	close(fd);
 
-	close(rtc);
-
-	if (utc) {
-		oldtz = getenv("TZ");
-		putenv((char*)"TZ=UTC0");
-		tzset();
-	}
-
-	t = mktime(&tm);
-
-	if (utc) {
-		unsetenv("TZ");
-		if (oldtz)
-			putenv(oldtz - 3);
-		tzset();
-	}
-	return t;
+	return ret;
 }
 
 static void write_rtc(time_t t, int utc)
 {
 	struct tm tm;
-	int rtc = xopen_rtc(O_WRONLY);
+	int rtc = rtc_xopen(rtcname, O_WRONLY);
 
 	tm = *(utc ? gmtime(&t) : localtime(&t));
 	tm.tm_isdst = 0;
@@ -132,38 +83,6 @@ static void from_sys_clock(int utc)
 	write_rtc(tv.tv_sec, utc);
 }
 
-#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
-# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
-#else
-# define ADJTIME_PATH "/etc/adjtime"
-#endif
-static int check_utc(void)
-{
-	int utc = 0;
-	FILE *f = fopen(ADJTIME_PATH, "r");
-
-	if (f) {
-		RESERVE_CONFIG_BUFFER(buffer, 128);
-
-		while (fgets(buffer, sizeof(buffer), f)) {
-			int len = strlen(buffer);
-
-			while (len && isspace(buffer[len - 1]))
-				len--;
-
-			buffer[len] = 0;
-
-			if (strncmp(buffer, "UTC", 3) == 0) {
-				utc = 1;
-				break;
-			}
-		}
-		fclose(f);
-		RELEASE_CONFIG_BUFFER(buffer);
-	}
-	return utc;
-}
-
 #define HWCLOCK_OPT_LOCALTIME   0x01
 #define HWCLOCK_OPT_UTC         0x02
 #define HWCLOCK_OPT_SHOW        0x04
@@ -193,19 +112,17 @@ int hwclock_main(int argc, char **argv)
 
 	/* If -u or -l wasn't given check if we are using utc */
 	if (opt & (HWCLOCK_OPT_UTC | HWCLOCK_OPT_LOCALTIME))
-		utc = opt & HWCLOCK_OPT_UTC;
+		utc = (opt & HWCLOCK_OPT_UTC);
 	else
-		utc = check_utc();
+		utc = rtc_adjtime_is_utc();
 
-	if (opt & HWCLOCK_OPT_HCTOSYS) {
+	if (opt & HWCLOCK_OPT_HCTOSYS)
 		to_sys_clock(utc);
-		return 0;
-	}
-	if (opt & HWCLOCK_OPT_SYSTOHC) {
+	else if (opt & HWCLOCK_OPT_SYSTOHC)
 		from_sys_clock(utc);
-		return 0;
-	}
-	/* default HWCLOCK_OPT_SHOW */
-	show_clock(utc);
+	else
+		/* default HWCLOCK_OPT_SHOW */
+		show_clock(utc);
+
 	return 0;
 }
diff --git a/util-linux/rtcwake.c b/util-linux/rtcwake.c
new file mode 100644
index 0000000..718f43d
--- /dev/null
+++ b/util-linux/rtcwake.c
@@ -0,0 +1,209 @@
+/*
+ * 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   "suspend"
+
+static time_t rtc_time;
+
+static int 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 0;
+
+	/* wakeup events could be disabled or not supported */
+	return strcmp(buf, "enabled\n") == 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);
+	}
+}
+
+static void suspend_system(const char *suspend)
+{
+	FILE *f = xfopen(SYS_POWER_PATH, "w");
+	fprintf(f, "%s\n", suspend);
+	fflush(f);
+	/* this executes after wake from suspend */
+	fclose(f);
+}
+
+#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, 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");
+
+	if (strcmp(suspend, "on") != 0 && !may_wakeup(rtcname))
+		bb_error_msg_and_die("%s not enabled for wakeup events", rtcname);
+
+	/* this RTC must exist and (if we'll sleep) be wakeup-enabled */
+	fd = rtc_xopen(rtcname, O_RDONLY);
+
+	/* 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"))
+		suspend_system(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;
+}