From 7eda085c41faa3445b4b168ce78ab18dab87d98a Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 7 Dec 2006 00:25:39 +0100 Subject: Imported from util-linux-2.9v tarball. --- clock/hwclock.c | 1290 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1290 insertions(+) create mode 100644 clock/hwclock.c (limited to 'clock/hwclock.c') diff --git a/clock/hwclock.c b/clock/hwclock.c new file mode 100644 index 000000000..a496e0570 --- /dev/null +++ b/clock/hwclock.c @@ -0,0 +1,1290 @@ +/* + * hwclock.c + * + * clock.c was written by Charles Hedrick, hedrick@cs.rutgers.edu, Apr 1992 + * Modified for clock adjustments - Rob Hooft , Nov 1992 + * Improvements by Harald Koenig + * and Alan Modra . + * + * Major rewrite by Bryan Henderson , 96.09.19. + * The new program is called hwclock. New features: + * - You can set the hardware clock without also modifying the system clock. + * - You can read and set the clock with finer than 1 second precision. + * - When you set the clock, hwclock automatically refigures the drift + * rate, based on how far off the clock was before you set it. + * + * Reshuffled things, added sparc code, and re-added alpha stuff + * by David Mosberger + * and Jay Estabrook + * and Martin Ostermann , aeb@cwi.nl, 990212. + * + * Fix for Award 2094 bug, Dave Coffin (dcoffin@shore.net) 11/12/98 + */ + +/* + * clock [-u] -r - read hardware clock + * clock [-u] -w - write hardware clock from system time + * clock [-u] -s - set system time from hardware clock + * clock [-u] -a - set system time from hardware clock, adjust the time + * to correct for systematic error, and write it back to + * the hardware clock + * -u indicates cmos clock is kept in universal time + * -A indicates cmos clock is kept in Alpha ARC console time (0 == 1980) + * -J indicates we're dealing with a Jensen (early DEC Alpha PC) + */ + +/* + * Explanation of `adjusting' (Rob Hooft): + * + * The problem with my machine is that its CMOS clock is 10 seconds + * per day slow. With this version of clock.c, and my '/etc/rc.local' + * reading '/etc/clock -au' instead of '/etc/clock -u -s', this error + * is automatically corrected at every boot. + * + * To do this job, the program reads and writes the file '/etc/adjtime' + * to determine the correction, and to save its data. In this file are + * three numbers: + * + * 1) the correction in seconds per day. (So if your clock runs 5 + * seconds per day fast, the first number should read -5.0) + * 2) the number of seconds since 1/1/1970 the last time the program + * was used + * 3) the remaining part of a second which was leftover after the last + * adjustment + * + * Installation and use of this program: + * + * a) create a file '/etc/adjtime' containing as the first and only line: + * '0.0 0 0.0' + * b) run 'clock -au' or 'clock -a', depending on whether your cmos is in + * universal or local time. This updates the second number. + * c) set your system time using the 'date' command. + * d) update your cmos time using 'clock -wu' or 'clock -w' + * e) replace the first number in /etc/adjtime by your correction. + * f) put the command 'clock -au' or 'clock -a' in your '/etc/rc.local' + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "clock.h" +#include "../version.h" +#include "nls.h" + +#define MYNAME "hwclock" +#define VERSION "2.4c" + +char *progname = MYNAME; + +/* The struct that holds our hardware access routines */ +struct clock_ops *ur; + +#define FLOOR(arg) ((arg >= 0 ? (int) arg : ((int) arg) - 1)); + +/* Here the information for time adjustments is kept. */ +#define ADJPATH "/etc/adjtime" + +/* Store the date here when "badyear" flag is set. */ +#define LASTDATE "/var/lib/lastdate" + +struct adjtime { + /* This is information we keep in the adjtime file that tells us how + to do drift corrections. Elements are all straight from the + adjtime file, so see documentation of that file for details. + Exception is , which is an indication that what's in this + structure is not what's in the disk file (because it has been + updated since read from the disk file). + */ + bool dirty; + float drift_factor; + time_t last_adj_time; + float not_adjusted; + time_t last_calib_time; +}; + +bool debug; + /* We are running in debug mode, wherein we put a lot of information about + what we're doing to standard output. */ + +bool badyear; + /* Workaround for Award 4.50g BIOS bug: keep the year in a file. */ + +/* + * Almost all Award BIOS's made between 04/26/94 and 05/31/95 + * have a nasty bug limiting the RTC year byte to the range 94-99. + * Any year between 2000 and 2093 gets changed to 2094, every time + * you start the system. + * With the --badyear option, we write the date to file and hope + * that the file is updated at least once a year. + * I recommend putting this command "hwclock --badyear" in the monthly + * crontab, just to be safe. -- Dave Coffin 11/12/98 + */ +void +write_date_to_file (struct tm *tm) { + FILE *fp; + + if ((fp = fopen(LASTDATE,"w"))) { + fprintf(fp,"%02d.%02d.%04d\n", tm->tm_mday, tm->tm_mon+1, + tm->tm_year+1900); + fclose(fp); + } else + perror(LASTDATE); +} + +void +read_date_from_file (struct tm *tm) { + int last_mday, last_mon, last_year; + FILE *fp; + + if ((fp = fopen(LASTDATE,"r"))) { + if (fscanf (fp,"%d.%d.%d\n", &last_mday, &last_mon, &last_year) == 3) { + tm->tm_year = last_year-1900; + if ((tm->tm_mon << 5) + tm->tm_mday < ((last_mon-1) << 5) + last_mday) + tm->tm_year ++; + } + fclose(fp); + } + write_date_to_file (tm); +} + +static float +time_diff(struct timeval subtrahend, struct timeval subtractor) { +/*--------------------------------------------------------------------------- + The difference in seconds between two times in "timeval" format. +----------------------------------------------------------------------------*/ + return( (subtrahend.tv_sec - subtractor.tv_sec) + + (subtrahend.tv_usec - subtractor.tv_usec) / 1E6 ); +} + + +static struct timeval +time_inc(struct timeval addend, float increment) { +/*---------------------------------------------------------------------------- + The time, in "timeval" format, which is seconds after + the time . Of course, may be negative. +-----------------------------------------------------------------------------*/ + struct timeval newtime; + + newtime.tv_sec = addend.tv_sec + (int) increment; + newtime.tv_usec = addend.tv_usec + (increment - (int) increment) * 1E6; + + /* Now adjust it so that the microsecond value is between 0 and 1 million */ + if (newtime.tv_usec < 0) { + newtime.tv_usec += 1E6; + newtime.tv_sec -= 1; + } else if (newtime.tv_usec >= 1E6) { + newtime.tv_usec -= 1E6; + newtime.tv_sec += 1; + } + return(newtime); +} + + + +static void +read_adjtime(struct adjtime *adjtime_p, int *rc_p) { +/*---------------------------------------------------------------------------- + Read the adjustment parameters out of the /etc/adjtime file. + + Return them as the adjtime structure <*adjtime_p>. + + If there is no /etc/adjtime file, return defaults. + If values are missing from the file, return defaults for them. + + return *rc_p = 0 if all OK, !=0 otherwise. + +-----------------------------------------------------------------------------*/ + FILE *adjfile; + int rc; /* local return code */ + struct stat statbuf; /* We don't even use the contents of this. */ + + rc = stat(ADJPATH, &statbuf); + if (rc < 0 && errno == ENOENT) { + /* He doesn't have a adjtime file, so we'll use defaults. */ + adjtime_p->drift_factor = 0; + adjtime_p->last_adj_time = 0; + adjtime_p->not_adjusted = 0; + adjtime_p->last_calib_time = 0; + + *rc_p = 0; + } else { + adjfile = fopen(ADJPATH, "r"); /* open file for reading */ + if (adjfile == NULL) { + outsyserr("cannot open file " ADJPATH); + *rc_p = 2; + } else { + char line1[81]; /* String: first line of adjtime file */ + char line2[81]; /* String: second line of adjtime file */ + + line1[0] = '\0'; /* In case fgets fails */ + fgets(line1, sizeof(line1), adjfile); + line2[0] = '\0'; /* In case fgets fails */ + fgets(line2, sizeof(line2), adjfile); + + fclose(adjfile); + + /* Set defaults in case values are missing from file */ + adjtime_p->drift_factor = 0; + adjtime_p->last_adj_time = 0; + adjtime_p->not_adjusted = 0; + adjtime_p->last_calib_time = 0; + + sscanf(line1, "%f %d %f", + &adjtime_p->drift_factor, + (int *) &adjtime_p->last_adj_time, + &adjtime_p->not_adjusted); + + sscanf(line2, "%d", (int *) &adjtime_p->last_calib_time); + + *rc_p = 0; + } + adjtime_p->dirty = FALSE; + + if (debug) { + printf(_("Last drift adjustment done at %d seconds after 1969\n"), + (int) adjtime_p->last_adj_time); + printf(_("Last calibration done at %d seconds after 1969\n"), + (int) adjtime_p->last_calib_time); + } + } +} + + +static void +synchronize_to_clock_tick(int *retcode_p) { +/*----------------------------------------------------------------------------- + Wait until the falling edge of the Hardware Clock's update flag so + that any time that is read from the clock immediately after we + return will be exact. + + The clock only has 1 second precision, so it gives the exact time only + once per second, right on the falling edge of the update flag. + + We wait (up to one second) either blocked waiting for an rtc device + or in a CPU spin loop. The former is probably not very accurate. + + Return *retcode_p == 0 if it worked, nonzero if it didn't. + +-----------------------------------------------------------------------------*/ + if (debug) printf(_("Waiting for clock tick...\n")); + + *retcode_p = ur->synchronize_to_clock_tick(); + + if (debug) printf(_("...got clock tick\n")); +} + + + +static void +mktime_tz(struct tm tm, const bool universal, + bool *valid_p, time_t *systime_p) { +/*----------------------------------------------------------------------------- + Convert a time in broken down format (hours, minutes, etc.) into standard + unix time (seconds into epoch). Return it as *systime_p. + + The broken down time is argument . This broken down time is either in + local time zone or UTC, depending on value of logical argument "universal". + True means it is in UTC. + + If the argument contains values that do not constitute a valid time, + and mktime() recognizes this, return *valid_p == false and + *systime_p undefined. However, mktime() sometimes goes ahead and + computes a fictional time "as if" the input values were valid, + e.g. if they indicate the 31st day of April, mktime() may compute + the time of May 1. In such a case, we return the same fictional + value mktime() does as *systime_p and return *valid_p == true. + +-----------------------------------------------------------------------------*/ + time_t mktime_result; /* The value returned by our mktime() call */ + char *zone; /* Local time zone name */ + + /* We use the C library function mktime(), but since it only works on + local time zone input, we may have to fake it out by temporarily + changing the local time zone to UTC. + */ + zone = (char *) getenv("TZ"); /* remember original time zone */ + mktime_result = mktime(&tm); + if (universal) { + /* Set timezone to UTC */ + setenv("TZ", "", TRUE); + /* Note: tzset() gets called implicitly by the time code, but only the + first time. When changing the environment variable, better call + tzset() explicitly. + */ + tzset(); + } + mktime_result = mktime(&tm); + if (mktime_result == -1) { + /* This apparently (not specified in mktime() documentation) means + the 'tm' structure does not contain valid values (however, not + containing valid values does _not_ imply mktime() returns -1). + */ + *valid_p = FALSE; + *systime_p = 0; + if (debug) + printf(_("Invalid values in hardware clock: " + "%2d/%.2d/%.2d %.2d:%.2d:%.2d\n"), + tm.tm_year, tm.tm_mon+1, tm.tm_mday, + tm.tm_hour, tm.tm_min, tm.tm_sec + ); + } else { + *valid_p = TRUE; + *systime_p = mktime_result; + if (debug) + printf(_("Hw clock time : %.2d:%.2d:%.2d = %d seconds since 1969\n"), + tm.tm_hour, tm.tm_min, tm.tm_sec, (int) *systime_p); + } + /* now put back the original zone. */ + if (zone) setenv("TZ", zone, TRUE); + else unsetenv("TZ"); + tzset(); +} + + +static void +read_hardware_clock(const bool universal, bool *valid_p, time_t *systime_p){ +/*---------------------------------------------------------------------------- + Read the hardware clock and return the current time via argument. + + Use the method indicated by argument to access the hardware clock. +-----------------------------------------------------------------------------*/ + struct tm tm; + int err; + + err = ur->read_hardware_clock(&tm); + + if (badyear) + read_date_from_file(&tm); + + if (debug) + printf (_("Time read from Hardware Clock: %02d:%02d:%02d\n"), + tm.tm_hour, tm.tm_min, tm.tm_sec); + mktime_tz(tm, universal, valid_p, systime_p); +} + + +static void +set_hardware_clock(const time_t newtime, + const bool universal, + const bool testing) { +/*---------------------------------------------------------------------------- + Set the Hardware Clock to the time , in local time zone or UTC, + according to . +----------------------------------------------------------------------------*/ + int err; + struct tm new_broken_time; + /* Time to which we will set Hardware Clock, in broken down format, in + the time zone of caller's choice + */ + + if (universal) + new_broken_time = *gmtime(&newtime); + else + new_broken_time = *localtime(&newtime); + + if (debug) + printf(_("Setting Hardware Clock to %.2d:%.2d:%.2d " + "= %d seconds since 1969\n"), + new_broken_time.tm_hour, new_broken_time.tm_min, + new_broken_time.tm_sec, (int) newtime); + + if (testing) + printf(_("Clock not changed - testing only.\n")); + else { + if (badyear) { + /* + * Write the real year to a file, then write a fake year + * between 1995 and 1998 to the RTC. This way, Award BIOS boots + * on 29 Feb 2000 thinking that it's 29 Feb 1996. + */ + write_date_to_file (&new_broken_time); + new_broken_time.tm_year = 95 + ((new_broken_time.tm_year+1) & 3); + } + err = ur->set_hardware_clock(&new_broken_time); + } +} + + + +static void +set_hardware_clock_exact(const time_t settime, + const struct timeval ref_time, + const bool universal, + const bool testing) { +/*---------------------------------------------------------------------------- + Set the Hardware Clock to the time "settime", in local time zone or UTC, + according to "universal". + + But correct "settime" and wait for a fraction of a second so that + "settime" is the value of the Hardware Clock as of system time + "ref_time", which is in the past. For example, if "settime" is + 14:03:05 and "ref_time" is 12:10:04.5 and the current system + time is 12:10:06.0: Wait .5 seconds (to make exactly 2 seconds since + "ref_time") and then set the Hardware Clock to 14:03:07, thus + getting a precise and retroactive setting of the clock. + + (Don't be confused by the fact that the system clock and the Hardware + Clock differ by two hours in the above example. That's just to remind + you that there are two independent time scales here). + + This function ought to be able to accept set times as fractional times. + Idea for future enhancement. + +-----------------------------------------------------------------------------*/ + time_t newtime; /* Time to which we will set Hardware Clock */ + struct timeval now_time; /* locally used time */ + + gettimeofday(&now_time, NULL); + newtime = settime + (int) time_diff(now_time, ref_time) + 1; + if (debug) + printf(_("Time elapsed since reference time has been %.6f seconds.\n" + "Delaying further to reach the next full second.\n"), + time_diff(now_time, ref_time)); + + /* Now delay some more until Hardware Clock time newtime arrives */ + do gettimeofday(&now_time, NULL); + while (time_diff(now_time, ref_time) < newtime - settime); + + set_hardware_clock(newtime, universal, testing); +} + + + +static void +display_time(const bool hclock_valid, const time_t systime, + const float sync_duration) { +/*---------------------------------------------------------------------------- + Put the time "systime" on standard output in display format. + Except if hclock_valid == false, just tell standard output that we don't + know what time it is. + + Include in the output the adjustment "sync_duration". +-----------------------------------------------------------------------------*/ + if (!hclock_valid) + fprintf(stderr, _("The Hardware Clock registers contain values that are " + "either invalid (e.g. 50th day of month) or beyond the range " + "we can handle (e.g. Year 2095).\n")); + else { + char *ctime_now; /* Address of static storage containing time string */ + + /* For some strange reason, ctime() is designed to include a newline + character at the end. We have to remove that. + */ + ctime_now = ctime(&systime); /* Compute display value for time */ + *(ctime_now+strlen(ctime_now)-1) = '\0'; /* Cut off trailing newline */ + + printf(_("%s %.6f seconds\n"), ctime_now, -(sync_duration)); + } +} + + + +static int +interpret_date_string(const char *date_opt, time_t * const time_p) { +/*---------------------------------------------------------------------------- + Interpret the value of the --date option, which is something like + "13:05:01". In fact, it can be any of the myriad ASCII strings that specify + a time which the "date" program can understand. The date option value in + question is our "dateopt" argument. + + The specified time is in the local time zone. + + Our output, "*time_p", is a seconds-into-epoch time. + + We use the "date" program to interpret the date string. "date" must be + runnable by issuing the command "date" to the /bin/sh shell. That means + in must be in the current PATH. + + If anything goes wrong (and many things can), we return return code + 10 and arbitrary *time_p. Otherwise, return code is 0 and *time_p + is valid. +----------------------------------------------------------------------------*/ + FILE *date_child_fp; + char date_resp[100]; + const char magic[]="seconds-into-epoch="; + char date_command[100]; + int retcode; /* our eventual return code */ + int rc; /* local return code */ + + if (date_opt == NULL) { + fprintf(stderr, _("No --date option specified.\n")); + retcode = 14; + } else if (strchr(date_opt, '"') != NULL) { + /* Quotation marks in date_opt would ruin the date command we construct. + */ + fprintf(stderr, _("The value of the --date option is not a valid date.\n" + "In particular, it contains quotation marks.\n")); + retcode = 12; + } else { + sprintf(date_command, "date --date=\"%s\" +seconds-into-epoch=%%s", + date_opt); + if (debug) printf(_("Issuing date command: %s\n"), date_command); + + date_child_fp = popen(date_command, "r"); + if (date_child_fp == NULL) { + outsyserr(_("Unable to run 'date' program in /bin/sh shell. " + "popen() failed")); + retcode = 10; + } else { + date_resp[0] = '\0'; /* in case fgets fails */ + fgets(date_resp, sizeof(date_resp), date_child_fp); + if (debug) printf(_("response from date command = %s\n"), date_resp); + if (strncmp(date_resp, magic, sizeof(magic)-1) != 0) { + fprintf(stderr, _("The date command issued by %s returned " + "unexpected results.\n" + "The command was:\n %s\nThe response was:\n %s\n"), + MYNAME, date_command, date_resp); + retcode = 8; + } else { + int seconds_since_epoch; + rc = sscanf(date_resp + sizeof(magic)-1, "%d", &seconds_since_epoch); + if (rc < 1) { + fprintf(stderr, _("The date command issued by %s returned" + "something other than an integer where the converted" + "time value was expected.\n" + "The command was:\n %s\nThe response was:\n %s\n"), + MYNAME, date_command, date_resp); + retcode = 6; + } else { + retcode = 0; + *time_p = seconds_since_epoch; + if (debug) + printf(_("date string %s equates to %d seconds since 1969.\n"), + date_opt, (int) *time_p); + } + } + fclose(date_child_fp); + } + } + return(retcode); +} + + + +static int +set_system_clock(const bool hclock_valid, const time_t newtime, + const bool testing) { +/*---------------------------------------------------------------------------- + Set the System Clock to time 'newtime'. + + Also set the kernel time zone value to the value indicated by the + TZ environment variable and/or /usr/lib/zoneinfo/, interpreted as + tzset() would interpret them. Except: do not consider Daylight + Savings Time to be a separate component of the time zone. Include + any effect of DST in the basic timezone value and set the kernel + DST value to 0. + + EXCEPT: if hclock_valid is false, just issue an error message + saying there is no valid time in the Hardware Clock to which to set + the system time. + + If 'testing' is true, don't actually update anything -- just say we + would have. +-----------------------------------------------------------------------------*/ + int retcode; /* our eventual return code */ + + if (!hclock_valid) { + fprintf(stderr,_("The Hardware Clock does not contain a valid time, so " + "we cannot set the System Time from it.\n")); + retcode = 1; + } else { + struct timeval tv; + int rc; /* local return code */ + + tv.tv_sec = newtime; + tv.tv_usec = 0; + + tzset(); /* init timezone, daylight from TZ or ...zoneinfo/localtime */ + /* An undocumented function of tzset() is to set global variabales + 'timezone' and 'daylight' + */ + + if (debug) { + printf( _("Calling settimeofday:\n") ); + printf( _("\ttv.tv_sec = %ld, tv.tv_usec = %ld\n"), + (long) tv.tv_sec, (long) tv.tv_usec ); + printf( _("\ttz.tz_minuteswest = %ld\n"), timezone/60 - 60*daylight); + } + if (testing) { + printf(_("Not setting system clock because running in test mode.\n")); + retcode = 0; + } else { + /* For documentation of settimeofday(), in addition to its man page, + see kernel/time.c in the Linux source code. + */ + const struct timezone tz = { timezone/60 - 60*daylight, 0 }; + /* put daylight in minuteswest rather than dsttime, + since the latter is mostly ignored ... */ + rc = settimeofday(&tv, &tz); + if (rc != 0) { + if (errno == EPERM) + fprintf(stderr, _("Must be superuser to set system clock.\n")); + else + outsyserr(_("settimeofday() failed")); + retcode = 1; + } else retcode = 0; + } + } + return(retcode); +} + + +static void +adjust_drift_factor(struct adjtime *adjtime_p, + const time_t nowtime, + const bool hclock_valid, const time_t hclocktime ) { +/*--------------------------------------------------------------------------- + Update the drift factor in <*adjtime_p> to reflect the fact that the + Hardware Clock was calibrated to and before that was set + to . + + We assume that the user has been doing regular drift adjustments + using the drift factor in the adjtime file, so if and + are different, that means the adjustment factor isn't + quite right. + + We record in the adjtime file the time at which we last calibrated + the clock so we can compute the drift rate each time we calibrate. + + EXCEPT: if is false, assume Hardware Clock was not set + before to anything meaningful and regular adjustments have not been + done, so don't adjust the drift factor. + +----------------------------------------------------------------------------*/ + if (!hclock_valid) { + if (debug) + printf(_("Not adjusting drift factor because the Hardware Clock " + "previously contained garbage.\n")); + } else if ((hclocktime - adjtime_p->last_calib_time) < 23 * 60 * 60) { + if (debug) + printf(_("Not adjusting drift factor because it has been less than a " + "day since the last calibration.\n")); + } else { + const float factor_adjust = + ((float) (nowtime - hclocktime) + / (hclocktime - adjtime_p->last_calib_time)) + * 24 * 60 * 60; + + if (debug) + printf(_("Clock drifted %d seconds in the past %d seconds " + "in spite of a drift factor of %f seconds/day.\n" + "Adjusting drift factor by %f seconds/day\n"), + (int) (nowtime - hclocktime), + (int) (hclocktime - adjtime_p->last_calib_time), + adjtime_p->drift_factor, + factor_adjust ); + + adjtime_p->drift_factor += factor_adjust; + } + adjtime_p->last_calib_time = nowtime; + + adjtime_p->last_adj_time = nowtime; + + adjtime_p->not_adjusted = 0; + + adjtime_p->dirty = TRUE; +} + + + +static void +calculate_adjustment( + const float factor, + const time_t last_time, + const float not_adjusted, + const time_t systime, + int *adjustment_p, + float *retro_p, + const int debug ) { +/*---------------------------------------------------------------------------- + Do the drift adjustment calculation. + + The way we have to set the clock, we need the adjustment in two parts: + + 1) an integer number of seconds (return as *adjustment_p) + + 2) a positive fraction of a second (less than 1) (return as *retro_p) + + The sum of these two values is the adjustment needed. Positive means to + advance the clock or insert seconds. Negative means to retard the clock + or remove seconds. +----------------------------------------------------------------------------*/ + float exact_adjustment; + + exact_adjustment = ((float) (systime - last_time)) * factor / (24 * 60 * 60) + + not_adjusted; + *adjustment_p = FLOOR(exact_adjustment); + + *retro_p = exact_adjustment - (float) *adjustment_p; + if (debug) { + printf (_("Time since last adjustment is %d seconds\n"), + (int) (systime - last_time)); + printf (_("Need to insert %d seconds and refer time back " + "%.6f seconds ago\n"), + *adjustment_p, *retro_p); + } +} + + + +static void +save_adjtime(const struct adjtime adjtime, const bool testing) { +/*----------------------------------------------------------------------------- + Write the contents of the structure to its disk file. + + But if the contents are clean (unchanged since read from disk), don't + bother. +-----------------------------------------------------------------------------*/ + char newfile[405]; /* Stuff to write to disk file */ + + if (adjtime.dirty) { + /* snprintf is not always available, but this is safe + as long as libc does not use more than 100 positions for %ld or %f */ + sprintf(newfile, "%f %ld %f\n%ld\n", + adjtime.drift_factor, + (long) adjtime.last_adj_time, + adjtime.not_adjusted, + (long) adjtime.last_calib_time ); + + if (testing) { + printf(_("Not updating adjtime file because of testing mode.\n")); + printf(_("Would have written the following to %s:\n%s"), + ADJPATH, newfile); + } else { + FILE *adjfile; + int err = 0; + + adjfile = fopen(ADJPATH, "w"); + if (adjfile == NULL) { + outsyserr("Could not open file with the clock adjustment parameters " + "in it (" ADJPATH ") for writing"); + err = 1; + } else { + if (fprintf(adjfile, newfile) < 0) { + outsyserr("Could not update file with the clock adjustment " + "parameters (" ADJPATH ") in it"); + err = 1; + } + if (fclose(adjfile) < 0) { + outsyserr("Could not update file with the clock adjustment " + "parameters (" ADJPATH ") in it"); + err = 1; + } + } + if (err) + fprintf(stderr, _("Drift adjustment parameters not updated.\n")); + } + } +} + + + +static void +do_adjustment(struct adjtime *adjtime_p, + const bool hclock_valid, const time_t hclocktime, + const struct timeval read_time, + const bool universal, const bool testing) { +/*--------------------------------------------------------------------------- + Do the adjustment requested, by 1) setting the Hardware Clock (if + necessary), and 2) updating the last-adjusted time in the adjtime + structure. + + Do not update anything if the Hardware Clock does not currently present + a valid time. + + arguments and are current values from the adjtime + file. + + means the Hardware Clock contains a valid time, and that + time is . + + is the current system time (to be precise, it is the system + time at the time was read, which due to computational delay + could be a short time ago). + + : the Hardware Clock is kept in UTC. + + : We are running in test mode (no updating of clock). + + We do not bother to update the clock if the adjustment would be less than + one second. This is to avoid cumulative error and needless CPU hogging + (remember we use an infinite loop for some timing) if the user runs us + frequently. + +----------------------------------------------------------------------------*/ + if (!hclock_valid) { + fprintf(stderr, _("The Hardware Clock does not contain a valid time, " + "so we cannot adjust it.\n")); + } else { + int adjustment; + /* Number of seconds we must insert in the Hardware Clock */ + float retro; + /* Fraction of second we have to remove from clock after inserting + whole seconds. + */ + calculate_adjustment(adjtime_p->drift_factor, + adjtime_p->last_adj_time, + adjtime_p->not_adjusted, + hclocktime, + &adjustment, &retro, + debug ); + if (adjustment > 0 || adjustment < -1) { + set_hardware_clock_exact(hclocktime + adjustment, + time_inc(read_time, -retro), + universal, testing); + adjtime_p->last_adj_time = hclocktime + adjustment; + adjtime_p->not_adjusted = 0; + adjtime_p->dirty = TRUE; + } else + if (debug) + printf(_("Needed adjustment is less than one second, " + "so not setting clock.\n")); + } +} + + + +static void +determine_clock_access_method(const bool user_requests_ISA) { + + ur = NULL; + + if (user_requests_ISA) + ur = probe_for_cmos_clock(); + + if (!ur) + ur = probe_for_rtc_clock(); + + if (!ur) + ur = probe_for_kd_clock(); + + if (!ur && !user_requests_ISA) + ur = probe_for_cmos_clock(); + + if (debug) { + if (ur) + printf(_("Using %s.\n"), ur->interface_name); + else + printf(_("No usable clock interface found.\n")); + } +} + +static void +manipulate_clock(const bool show, const bool adjust, + const bool set, const time_t set_time, + const bool hctosys, const bool systohc, + const struct timeval startup_time, + const bool universal, const bool testing, + int *retcode_p + ) { +/*--------------------------------------------------------------------------- + Do all the normal work of hwclock - read, set clock, etc. + + Issue output to stdout and error message to stderr where appropriate. + + Return rc == 0 if everything went OK, rc != 0 if not. +----------------------------------------------------------------------------*/ + struct adjtime adjtime; + /* Contents of the adjtime file, or what they should be. */ + int rc; /* local return code */ + bool no_auth; /* User lacks necessary authorization to access the clock */ + + no_auth = ur->get_permissions(); + + if (no_auth) *retcode_p = 1; + else { + if (adjust || set || systohc) + read_adjtime(&adjtime, &rc); + else { + /* A little trick to avoid reading the file if we don't have to */ + adjtime.dirty = FALSE; + rc = 0; + } + if (rc != 0) *retcode_p = 2; + else { + synchronize_to_clock_tick(retcode_p); + /* this takes up to 1 second */ + if (*retcode_p == 0) { + struct timeval read_time; + /* The time at which we read the Hardware Clock */ + + bool hclock_valid; + /* The Hardware Clock gives us a valid time, or at least something + close enough to fool mktime(). + */ + + time_t hclocktime; + /* The time the hardware clock had just after we + synchronized to its next clock tick when we started up. + Defined only if hclock_valid is true. + */ + + gettimeofday(&read_time, NULL); + read_hardware_clock(universal, &hclock_valid, &hclocktime); + + if (show) { + display_time(hclock_valid, hclocktime, + time_diff(read_time, startup_time)); + *retcode_p = 0; + } else if (set) { + set_hardware_clock_exact(set_time, startup_time, + universal, testing); + adjust_drift_factor(&adjtime, set_time, hclock_valid, hclocktime); + *retcode_p = 0; + } else if (adjust) { + do_adjustment(&adjtime, hclock_valid, hclocktime, + read_time, universal, testing); + *retcode_p = 0; + } else if (systohc) { + struct timeval nowtime, reftime; + /* We can only set_hardware_clock_exact to a whole seconds + time, so we set it with reference to the most recent + whole seconds time. + */ + gettimeofday(&nowtime, NULL); + reftime.tv_sec = nowtime.tv_sec; + reftime.tv_usec = 0; + + set_hardware_clock_exact((time_t) reftime.tv_sec, reftime, + universal, testing); + *retcode_p = 0; + adjust_drift_factor(&adjtime, (time_t) reftime.tv_sec, hclock_valid, + hclocktime); + } else if (hctosys) { + rc = set_system_clock(hclock_valid, hclocktime, testing); + if (rc != 0) { + printf(_("Unable to set system clock.\n")); + *retcode_p = 1; + } else *retcode_p = 0; + } + save_adjtime(adjtime, testing); + } + } + } +} + + +static void +manipulate_epoch(const bool getepoch, const bool setepoch, + const int epoch_opt, const bool testing) { +/*---------------------------------------------------------------------------- + Get or set the Hardware Clock epoch value in the kernel, as appropriate. + , , and are hwclock invocation options. + + == -1 if the user did not specify an "epoch" option. + +-----------------------------------------------------------------------------*/ + /* + Maintenance note: This should work on non-Alpha machines, but the + evidence today (98.03.04) indicates that the kernel only keeps the + epoch value on Alphas. If that is ever fixed, this function should be + changed. + */ + +#ifndef __alpha__ + fprintf(stderr, _("The kernel keeps an epoch value for the Hardware Clock " + "only on an Alpha machine.\nThis copy of hwclock was built for " + "a machine other than Alpha\n(and thus is presumably not running " + "on an Alpha now). No action taken.\n")); +#else + if (getepoch) { + unsigned long epoch; + + if (get_epoch_rtc(&epoch, 0)) + fprintf(stderr, _("Unable to get the epoch value from the kernel.\n")); + else + printf(_("Kernel is assuming an epoch value of %lu\n"), epoch); + } else if (setepoch) { + if (epoch_opt == -1) + fprintf(stderr, _("To set the epoch value, you must use the 'epoch' " + "option to tell to what value to set it.\n")); + else if (testing) + printf(_("Not setting the epoch to %d - testing only.\n"), + epoch_opt); + else if (set_epoch_rtc(epoch_opt)) + printf(_("Unable to set the epoch value in the kernel.\n")); + } +#endif +} + +int +main(int argc, char **argv, char **envp) { + + struct timeval startup_time; + /* The time we started up, in seconds into the epoch, including fractions. + */ + time_t set_time; /* Time to which user said to set Hardware Clock */ + + bool permitted; /* User is permitted to do the function */ + int retcode; /* Our eventual return code */ + + int rc; /* local return code */ + + /* option_def is the control table for the option parser. These other + variables are the results of parsing the options and their meanings + are given by the option_def. The only exception is , which + may be modified after parsing is complete to effect an implied option. + */ + bool show, set, systohc, hctosys, adjust, getepoch, setepoch, version; + bool ARCconsole, universal, testing, directisa, Jensen, SRM, funky_toy; + char *date_opt; + int epoch_opt; + + const optStruct option_def[] = { + { 'r', (char *) "show", OPT_FLAG, &show, 0 }, + { 0, (char *) "set", OPT_FLAG, &set, 0 }, + { 'w', (char *) "systohc", OPT_FLAG, &systohc, 0 }, + { 's', (char *) "hctosys", OPT_FLAG, &hctosys, 0 }, + { 0, (char *) "getepoch", OPT_FLAG, &getepoch, 0 }, + { 0, (char *) "setepoch", OPT_FLAG, &setepoch, 0 }, + { 'a', (char *) "adjust", OPT_FLAG, &adjust, 0 }, + { 'v', (char *) "version", OPT_FLAG, &version, 0 }, + { 0, (char *) "date", OPT_STRING, &date_opt, 0 }, + { 0, (char *) "epoch", OPT_UINT, &epoch_opt, 0 }, + { 'u', (char *) "utc", OPT_FLAG, &universal, 0 }, + { 0, (char *) "badyear", OPT_FLAG, &badyear, 0 }, + { 0, (char *) "directisa", OPT_FLAG, &directisa, 0 }, + { 0, (char *) "test", OPT_FLAG, &testing, 0 }, + { 'D', (char *) "debug", OPT_FLAG, &debug, 0 }, +#ifdef __alpha__ + { 'A', (char *) "ARC", OPT_FLAG, &ARCconsole,0 }, + { 'J', (char *) "Jensen", OPT_FLAG, &Jensen, 0 }, + { 'S', (char *) "SRM", OPT_FLAG, &SRM, 0 }, + { 'F', (char *) "funky-toy", OPT_FLAG, &funky_toy, 0 }, +#endif + { 0, (char *) NULL, OPT_END, NULL, 0 } + }; + int argc_parse; /* argc, except we modify it as we parse */ + char **argv_parse; /* argv, except we modify it as we parse */ + + gettimeofday(&startup_time, NULL); /* Remember what time we were invoked */ + + setlocale(LC_ALL, ""); + bindtextdomain(PACKAGE, LOCALEDIR); + textdomain(PACKAGE); + + /* set option defaults */ + show = set = systohc = hctosys = adjust = getepoch = setepoch = + version = universal = ARCconsole = SRM = funky_toy = + directisa = badyear = Jensen = testing = debug = FALSE; + date_opt = NULL; + epoch_opt = -1; + + argc_parse = argc; argv_parse = argv; + optParseOptions(&argc_parse, argv_parse, option_def, 0); + /* Uses and sets argc_parse, argv_parse. + Sets show, systohc, hctosys, adjust, universal, version, testing, + debug, set, date_opt, getepoch, setepoch, epoch_opt + */ + /* This is an ugly routine - for example, if I give an incorrect + option, it only says "unrecognized option" without telling + me what options are recognized. Rewrite with standard + getopt() and usage() and throw shhopt out. */ + + if (argc_parse - 1 > 0) { + fprintf(stderr, _("%s takes no non-option arguments. " + "You supplied %d.\n"), + MYNAME, argc_parse - 1); + exit(100); + } + + if (show + set + systohc + hctosys + adjust + + getepoch + setepoch + version > 1) { + fprintf(stderr, _("You have specified multiple function options.\n" + "You can only perform one function at a time.\n")); + exit(100); + } + +#ifdef __alpha__ + set_cmos_epoch(ARCconsole, SRM); + set_cmos_access(Jensen, funky_toy); +#endif + + if (set) { + rc = interpret_date_string(date_opt, &set_time); /* (time-consuming) */ + if (rc != 0) { + fprintf(stderr, _("No usable set-to time. Cannot set clock.\n")); + exit(100); + } + } + + if (!(show | set | systohc | hctosys | adjust | getepoch | setepoch | + version)) + show = 1; /* default to show */ + + + if (getuid() == 0) permitted = TRUE; + else { + /* program is designed to run setuid (in some situations) -- be secure! */ + if (set || hctosys || systohc || adjust) { + fprintf(stderr, + _("Sorry, only the superuser can change the Hardware Clock.\n")); + permitted = FALSE; + } else if (setepoch) { + fprintf(stderr, + _("Sorry, only the superuser can change " + "the Hardware Clock epoch in the kernel.\n")); + permitted = FALSE; + } else permitted = TRUE; + } + + if (!permitted) retcode = 2; + else { + retcode = 0; + if (version) { + printf(MYNAME " " VERSION "/%s\n",util_linux_version); + } else if (getepoch || setepoch) { + manipulate_epoch(getepoch, setepoch, epoch_opt, testing); + } else { + determine_clock_access_method(directisa); + if (!ur) + fprintf(stderr, _("Cannot access the Hardware Clock via any known " + "method. Use --debug option to see the details of our " + "search for an access method.\n")); + else + manipulate_clock(show, adjust, set, set_time, hctosys, systohc, + startup_time, universal, testing, &rc); + } + } + exit(retcode); +} + +/* A single routine for greater uniformity */ +void +outsyserr(char *msg) { + fprintf(stderr, _("%s: %s, errno=%d: %s.\n"), + progname, msg, errno, strerror(errno)); +} + +/**************************************************************************** + + History of this program: + + 98.08.12 BJH Version 2.4 + + Don't use century byte from Hardware Clock. Add comments telling why. + + + 98.06.20 BJH Version 2.3. + + Make --hctosys set the kernel timezone from TZ environment variable + and/or /usr/lib/zoneinfo. From Klaus Ripke (klaus@ripke.com). + + 98.03.05 BJH. Version 2.2. + + Add --getepoch and --setepoch. + + Fix some word length things so it works on Alpha. + + Make it work when /dev/rtc doesn't have the interrupt functions. + In this case, busywait for the top of a second instead of blocking and + waiting for the update complete interrupt. + + Fix a bunch of bugs too numerous to mention. + + 97.06.01: BJH. Version 2.1. Read and write the century byte (Byte + 50) of the ISA Hardware Clock when using direct ISA I/O. Problem + discovered by job (jei@iclnl.icl.nl). + + Use the rtc clock access method in preference to the KDGHWCLK method. + Problem discovered by Andreas Schwab . + + November 1996: Version 2.0.1. Modifications by Nicolai Langfeldt + (janl@math.uio.no) to make it compile on linux 1.2 machines as well + as more recent versions of the kernel. Introduced the NO_CLOCK + access method and wrote feature test code to detect absense of rtc + headers. + + +************************************************************************** + Maintenance notes + + To compile this, you must use GNU compiler optimization (-O option) + in order to make the "extern inline" functions from asm/io.h (inb(), + etc.) compile. If you don't optimize, which means the compiler + will generate no inline functions, the references to these functions + in this program will be compiled as external references. Since you + probably won't be linking with any functions by these names, you will + have unresolved external references when you link. + + The program is designed to run setuid superuser, since we need to be + able to do direct I/O. (More to the point: we need permission to + execute the iopl() system call). (However, if you use one of the + methods other than direct ISA I/O to access the clock, no setuid is + required). + + Here's some info on how we must deal with the time that elapses while + this program runs: There are two major delays as we run: + + 1) Waiting up to 1 second for a transition of the Hardware Clock so + we are synchronized to the Hardware Clock. + + 2) Running the "date" program to interpret the value of our --date + option. + + Reading the /etc/adjtime file is the next biggest source of delay and + uncertainty. + + The user wants to know what time it was at the moment he invoked us, + not some arbitrary time later. And in setting the clock, he is + giving us the time at the moment we are invoked, so if we set the + clock some time later, we have to add some time to that. + + So we check the system time as soon as we start up, then run "date" + and do file I/O if necessary, then wait to synchronize with a + Hardware Clock edge, then check the system time again to see how + much time we spent. We immediately read the clock then and (if + appropriate) report that time, and additionally, the delay we measured. + + If we're setting the clock to a time given by the user, we wait some + more so that the total delay is an integral number of seconds, then + set the Hardware Clock to the time the user requested plus that + integral number of seconds. N.B. The Hardware Clock can only be set + in integral seconds. + + If we're setting the clock to the system clock value, we wait for + the system clock to reach the top of a second, and then set the + Hardware Clock to the system clock's value. + + Here's an interesting point about setting the Hardware Clock: On my + machine, when you set it, it sets to that precise time. But one can + imagine another clock whose update oscillator marches on a steady one + second period, so updating the clock between any two oscillator ticks + is the same as updating it right at the earlier tick. To avoid any + complications that might cause, we set the clock as soon as possible + after an oscillator tick. + + + About synchronizing to the Hardware Clock when reading the time: The + precision of the Hardware Clock counters themselves is one second. + You can't read the counters and find out that is 12:01:02.5. But if + you consider the location in time of the counter's ticks as part of + its value, then its precision is as infinite as time is continuous! + What I'm saying is this: To find out the _exact_ time in the + hardware clock, we wait until the next clock tick (the next time the + second counter changes) and measure how long we had to wait. We + then read the value of the clock counters and subtract the wait time + and we know precisely what time it was when we set out to query the + time. + + hwclock uses this method, and considers the Hardware Clock to have + infinite precision. + + + Enhancements needed: + + - When waiting for whole second boundary in set_hardware_clock_exact, + fail if we miss the goal by more than .1 second, as could happen if + we get pre-empted (by the kernel dispatcher). + +****************************************************************************/ + -- cgit v1.2.3-55-g7522