*
* Copyright (C) 2002 Robert Griebl <griebl@gmx.de>
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
-*/
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+//config:config HWCLOCK
+//config: bool "hwclock (5.8 kb)"
+//config: default y
+//config: select PLATFORM_LINUX
+//config: help
+//config: The hwclock utility is used to read and set the hardware clock
+//config: on a system. This is primarily used to set the current time on
+//config: shutdown in the hardware clock, so the hardware will keep the
+//config: correct time when Linux is _not_ running.
+//config:
+//config:config FEATURE_HWCLOCK_ADJTIME_FHS
+//config: bool "Use FHS /var/lib/hwclock/adjtime"
+//config: default n # util-linux-ng in Fedora 13 still uses /etc/adjtime
+//config: depends on HWCLOCK
+//config: help
+//config: Starting with FHS 2.3, the adjtime state file is supposed to exist
+//config: at /var/lib/hwclock/adjtime instead of /etc/adjtime. If you wish
+//config: to use the FHS behavior, answer Y here, otherwise answer N for the
+//config: classic /etc/adjtime path.
+//config:
+//config: pathname.com/fhs/pub/fhs-2.3.html#VARLIBHWCLOCKSTATEDIRECTORYFORHWCLO
+
+//applet:IF_HWCLOCK(APPLET(hwclock, BB_DIR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_HWCLOCK) += hwclock.o
-#include <sys/utsname.h>
-#include <getopt.h>
#include "libbb.h"
+/* After libbb.h, since it needs sys/types.h on some systems */
+#include <sys/utsname.h>
+#include "rtc_.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 */
-
-#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
-# ifndef _GNU_SOURCE
-# define _GNU_SOURCE
-# endif
-#endif
+/* diff code is disabled: it's not sys/hw clock diff, it's some useless
+ * "time between hwclock was started and we saw CMOS tick" quantity.
+ * It's useless since hwclock is started at a random moment,
+ * thus the quantity is also random, useless. Showing 0.000000 does not
+ * deprive us from any useful info.
+ *
+ * SHOW_HWCLOCK_DIFF code in this file shows the difference between system
+ * and hw clock. It is useful, but not compatible with standard hwclock.
+ * Thus disabled.
+ */
+#define SHOW_HWCLOCK_DIFF 0
-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)
+#if !SHOW_HWCLOCK_DIFF
+# define read_rtc(pp_rtcname, sys_tv, utc) read_rtc(pp_rtcname, utc)
+#endif
+static time_t read_rtc(const char **pp_rtcname, struct timeval *sys_tv, int utc)
{
- struct tm tm;
- char *oldtz = 0;
- time_t t = 0;
- int rtc = xopen_rtc(O_RDONLY);
-
- memset(&tm, 0, sizeof(struct tm));
- xioctl(rtc, RTC_RD_TIME, &tm);
- tm.tm_isdst = -1; /* not known */
-
- close(rtc);
+ struct tm tm_time;
+ int fd;
- if (utc) {
- oldtz = getenv("TZ");
- putenv((char*)"TZ=UTC0");
- tzset();
- }
+ fd = rtc_xopen(pp_rtcname, O_RDONLY);
- t = mktime(&tm);
+ rtc_read_tm(&tm_time, fd);
- if (utc) {
- unsetenv("TZ");
- if (oldtz)
- putenv(oldtz - 3);
- tzset();
+#if SHOW_HWCLOCK_DIFF
+ {
+ int before = tm_time.tm_sec;
+ while (1) {
+ rtc_read_tm(&tm_time, fd);
+ gettimeofday(sys_tv, NULL);
+ if (before != (int)tm_time.tm_sec)
+ break;
+ }
}
- return t;
-}
-
-static void write_rtc(time_t t, int utc)
-{
- struct tm tm;
- int rtc = xopen_rtc(O_WRONLY);
-
- tm = *(utc ? gmtime(&t) : localtime(&t));
- tm.tm_isdst = 0;
+#endif
- xioctl(rtc, RTC_SET_TIME, &tm);
+ if (ENABLE_FEATURE_CLEAN_UP)
+ close(fd);
- close(rtc);
+ return rtc_tm2time(&tm_time, utc);
}
-static void show_clock(int utc)
+static void show_clock(const char **pp_rtcname, int utc)
{
- //struct tm *ptm;
- time_t t;
- char *cp;
-
- t = read_rtc(utc);
- //ptm = localtime(&t); /* Sets 'tzname[]' */
+#if SHOW_HWCLOCK_DIFF
+ struct timeval sys_tv;
+#endif
+ time_t t = read_rtc(pp_rtcname, &sys_tv, utc);
- cp = ctime(&t);
- if (cp[0])
- cp[strlen(cp) - 1] = '\0';
+#if ENABLE_LOCALE_SUPPORT
+ /* Standard hwclock uses locale-specific output format */
+ char cp[64];
+ struct tm *ptm = localtime(&t);
+ strftime(cp, sizeof(cp), "%c", ptm);
+#else
+ char *cp = ctime(&t);
+ chomp(cp);
+#endif
- //printf("%s %.6f seconds %s\n", cp, 0.0, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0]));
+#if !SHOW_HWCLOCK_DIFF
printf("%s 0.000000 seconds\n", cp);
+#else
+ {
+ long diff = sys_tv.tv_sec - t;
+ if (diff < 0 /*&& tv.tv_usec != 0*/) {
+ /* Why we need diff++? */
+ /* diff >= 0 is ok: | diff < 0, can't just use tv.tv_usec: */
+ /* 45.520820 | 43.520820 */
+ /* - 44.000000 | - 45.000000 */
+ /* = 1.520820 | = -1.479180, not -2.520820! */
+ diff++;
+ /* Should be 1000000 - tv.tv_usec, but then we must check tv.tv_usec != 0 */
+ sys_tv.tv_usec = 999999 - sys_tv.tv_usec;
+ }
+ printf("%s %ld.%06lu seconds\n", cp, diff, (unsigned long)sys_tv.tv_usec);
+ }
+#endif
}
-static void to_sys_clock(int utc)
+static void to_sys_clock(const char **pp_rtcname, int utc)
{
struct timeval tv;
- const struct timezone tz = { timezone/60 - 60*daylight, 0 };
+ struct timezone tz;
- tv.tv_sec = read_rtc(utc);
+ tz.tz_minuteswest = timezone/60;
+ /* ^^^ used to also subtract 60*daylight, but it's wrong:
+ * daylight!=0 means "this timezone has some DST
+ * during the year", not "DST is in effect now".
+ */
+ tz.tz_dsttime = 0;
+
+ tv.tv_sec = read_rtc(pp_rtcname, NULL, utc);
tv.tv_usec = 0;
if (settimeofday(&tv, &tz))
- bb_perror_msg_and_die("settimeofday() failed");
+ bb_perror_msg_and_die("settimeofday");
}
-static void from_sys_clock(int utc)
+static void from_sys_clock(const char **pp_rtcname, int utc)
{
+#if 1
struct timeval tv;
+ struct tm tm_time;
+ int rtc;
+ rtc = rtc_xopen(pp_rtcname, O_WRONLY);
gettimeofday(&tv, NULL);
- //if (gettimeofday(&tv, NULL))
- // bb_perror_msg_and_die("gettimeofday() failed");
- write_rtc(tv.tv_sec, utc);
-}
-
-#ifdef CONFIG_FEATURE_HWCLOCK_ADJTIME_FHS
-# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
+ /* Prepare tm_time */
+ if (sizeof(time_t) == sizeof(tv.tv_sec)) {
+ if (utc)
+ gmtime_r((time_t*)&tv.tv_sec, &tm_time);
+ else
+ localtime_r((time_t*)&tv.tv_sec, &tm_time);
+ } else {
+ time_t t = tv.tv_sec;
+ if (utc)
+ gmtime_r(&t, &tm_time);
+ else
+ localtime_r(&t, &tm_time);
+ }
#else
-# define ADJTIME_PATH "/etc/adjtime"
-#endif
-static int check_utc(void)
-{
- int utc = 0;
- FILE *f = fopen(ADJTIME_PATH, "r");
+/* Bloated code which tries to set hw clock with better precision.
+ * On x86, even though code does set hw clock within <1ms of exact
+ * whole seconds, apparently hw clock (at least on some machines)
+ * doesn't reset internal fractional seconds to 0,
+ * making all this a pointless exercise.
+ */
+ /* If we see that we are N usec away from whole second,
+ * we'll sleep for N-ADJ usecs. ADJ corrects for the fact
+ * that CPU is not infinitely fast.
+ * On infinitely fast CPU, next wakeup would be
+ * on (exactly_next_whole_second - ADJ). On real CPUs,
+ * this difference between current time and whole second
+ * is less than ADJ (assuming system isn't heavily loaded).
+ */
+ /* Small value of 256us gives very precise sync for 2+ GHz CPUs.
+ * Slower CPUs will fail to sync and will go to bigger
+ * ADJ values. qemu-emulated armv4tl with ~100 MHz
+ * performance ends up using ADJ ~= 4*1024 and it takes
+ * 2+ secs (2 tries with successively larger ADJ)
+ * to sync. Even straced one on the same qemu (very slow)
+ * takes only 4 tries.
+ */
+#define TWEAK_USEC 256
+ unsigned adj = TWEAK_USEC;
+ struct tm tm_time;
+ struct timeval tv;
+ int rtc = rtc_xopen(pp_rtcname, O_WRONLY);
- if (f) {
- RESERVE_CONFIG_BUFFER(buffer, 128);
+ /* Try to catch the moment when whole second is close */
+ while (1) {
+ unsigned rem_usec;
+ time_t t;
- while (fgets(buffer, sizeof(buffer), f)) {
- int len = strlen(buffer);
+ gettimeofday(&tv, NULL);
- while (len && isspace(buffer[len - 1]))
- len--;
+ t = tv.tv_sec;
+ rem_usec = 1000000 - tv.tv_usec;
+ if (rem_usec < adj) {
+ /* Close enough */
+ small_rem:
+ t++;
+ }
- buffer[len] = 0;
+ /* Prepare tm_time from t */
+ if (utc)
+ gmtime_r(&t, &tm_time); /* may read /etc/xxx (it takes time) */
+ else
+ localtime_r(&t, &tm_time); /* same */
- if (strncmp(buffer, "UTC", 3) == 0) {
- utc = 1;
- break;
- }
+ if (adj >= 32*1024) {
+ break; /* 32 ms diff and still no luck?? give up trying to sync */
+ }
+
+ /* gmtime/localtime took some time, re-get cur time */
+ gettimeofday(&tv, NULL);
+
+ if (tv.tv_sec < t /* we are still in old second */
+ || (tv.tv_sec == t && tv.tv_usec < adj) /* not too far into next second */
+ ) {
+ break; /* good, we are in sync! */
+ }
+
+ rem_usec = 1000000 - tv.tv_usec;
+ if (rem_usec < adj) {
+ t = tv.tv_sec;
+ goto small_rem; /* already close to next sec, don't sleep */
+ }
+
+ /* Try to sync up by sleeping */
+ usleep(rem_usec - adj);
+
+ /* Jump to 1ms diff, then increase fast (x2): EVERY loop
+ * takes ~1 sec, people won't like slowly converging code here!
+ */
+ //bb_error_msg("adj:%d tv.tv_usec:%d", adj, (int)tv.tv_usec);
+ if (adj < 512)
+ adj = 512;
+ /* ... and if last "overshoot" does not look insanely big,
+ * just use it as adj increment. This makes convergence faster.
+ */
+ if (tv.tv_usec < adj * 8) {
+ adj += tv.tv_usec;
+ continue;
}
- fclose(f);
- RELEASE_CONFIG_BUFFER(buffer);
+ adj *= 2;
}
- return utc;
+ /* Debug aid to find "optimal" TWEAK_USEC with nearly exact sync.
+ * Look for a value which makes tv_usec close to 999999 or 0.
+ * For 2.20GHz Intel Core 2: optimal TWEAK_USEC ~= 200
+ */
+ //bb_error_msg("tv.tv_usec:%d", (int)tv.tv_usec);
+#endif
+
+ tm_time.tm_isdst = 0;
+ xioctl(rtc, RTC_SET_TIME, &tm_time);
+
+ if (ENABLE_FEATURE_CLEAN_UP)
+ close(rtc);
}
+/*
+ * At system boot, kernel may set system time from RTC,
+ * but it knows nothing about timezones. If RTC is in local time,
+ * then system time is wrong - it is offset by timezone.
+ * This option corrects system time if RTC is in local time,
+ * and (always) sets in-kernel timezone.
+ *
+ * This is an alternate option to --hctosys that does not read the
+ * hardware clock.
+ */
+static void set_system_clock_timezone(int utc)
+{
+ struct timeval tv;
+ struct tm *broken;
+ struct timezone tz;
+
+ gettimeofday(&tv, NULL);
+ broken = localtime(&tv.tv_sec);
+ tz.tz_minuteswest = timezone / 60;
+ if (broken->tm_isdst > 0)
+ tz.tz_minuteswest -= 60;
+ tz.tz_dsttime = 0;
+ gettimeofday(&tv, NULL);
+ if (!utc)
+ tv.tv_sec += tz.tz_minuteswest * 60;
+ if (settimeofday(&tv, &tz))
+ bb_perror_msg_and_die("settimeofday");
+}
+
+//usage:#define hwclock_trivial_usage
+//usage: IF_LONG_OPTS(
+//usage: "[-r|--show] [-s|--hctosys] [-w|--systohc] [--systz]"
+//usage: " [--localtime] [-u|--utc]"
+//usage: " [-f|--rtc FILE]"
+//usage: )
+//usage: IF_NOT_LONG_OPTS(
+//usage: "[-r] [-s] [-w] [-t] [-l] [-u] [-f FILE]"
+//usage: )
+//usage:#define hwclock_full_usage "\n\n"
+//usage: "Query and set hardware clock (RTC)\n"
+//usage: "\n -r Show hardware clock time"
+//usage: "\n -s Set system time from hardware clock"
+//usage: "\n -w Set hardware clock from system time"
+//usage: IF_LONG_OPTS(
+//usage: "\n --systz Set in-kernel timezone, correct system time"
+//usage: )
+//usage: "\n if hardware clock is in local time"
+//usage: "\n -u Assume hardware clock is kept in UTC"
+//usage: IF_LONG_OPTS(
+//usage: "\n --localtime Assume hardware clock is kept in local time"
+//usage: )
+//usage: "\n -f FILE Use specified device (e.g. /dev/rtc2)"
+
+//TODO: get rid of incompatible -t and -l aliases to --systz and --localtime
+
#define HWCLOCK_OPT_LOCALTIME 0x01
#define HWCLOCK_OPT_UTC 0x02
#define HWCLOCK_OPT_SHOW 0x04
#define HWCLOCK_OPT_HCTOSYS 0x08
#define HWCLOCK_OPT_SYSTOHC 0x10
-#define HWCLOCK_OPT_RTCFILE 0x20
+#define HWCLOCK_OPT_SYSTZ 0x20
+#define HWCLOCK_OPT_RTCFILE 0x40
-int hwclock_main(int argc, char **argv);
-int hwclock_main(int argc, char **argv)
+int hwclock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int hwclock_main(int argc UNUSED_PARAM, char **argv)
{
+ const char *rtcname = NULL;
unsigned opt;
int utc;
-#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
+#if ENABLE_LONG_OPTS
static const char hwclock_longopts[] ALIGN1 =
- "localtime\0" No_argument "l"
+ "localtime\0" No_argument "l" /* short opt is non-standard */
"utc\0" No_argument "u"
"show\0" No_argument "r"
"hctosys\0" No_argument "s"
"systohc\0" No_argument "w"
- "file\0" Required_argument "f"
+ "systz\0" No_argument "t" /* short opt is non-standard */
+ "rtc\0" Required_argument "f"
;
- applet_long_options = hwclock_longopts;
#endif
- opt_complementary = "r--ws:w--rs:s--wr:l--u:u--l";
- opt = getopt32(argc, argv, "lurswf:", &rtcname);
+
+ /* Initialize "timezone" (libc global variable) */
+ tzset();
+
+ opt = getopt32long(argv,
+ "^lurswtf:" "\0" "r--wst:w--rst:s--wrt:t--rsw:l--u:u--l",
+ hwclock_longopts,
+ &rtcname
+ );
/* 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 = rtc_adjtime_is_utc();
+
+ if (opt & HWCLOCK_OPT_HCTOSYS)
+ to_sys_clock(&rtcname, utc);
+ else if (opt & HWCLOCK_OPT_SYSTOHC)
+ from_sys_clock(&rtcname, utc);
+ else if (opt & HWCLOCK_OPT_SYSTZ)
+ set_system_clock_timezone(utc);
else
- utc = check_utc();
+ /* default HWCLOCK_OPT_SHOW */
+ show_clock(&rtcname, utc);
- if (opt & HWCLOCK_OPT_HCTOSYS) {
- to_sys_clock(utc);
- return 0;
- }
- if (opt & HWCLOCK_OPT_SYSTOHC) {
- from_sys_clock(utc);
- return 0;
- }
- /* default HWCLOCK_OPT_SHOW */
- show_clock(utc);
return 0;
}
projects / oweals / busybox.git / blobdiff