source: trunk/minix/commands/ibm/readclock.c@ 15

/* setime - set the system time from the real time clock
                                        Authors: T. Holm & E. Froese
                                        Adapted by: Jorrit .N. Herder */

/************************************************************************/
/*   Readclock was updated for security reasons: openeing /dev/mem no   */
/*   longer automatically grants I/O privileges to the calling process  */
/*   so that the CMOS' clock could not be read from this program. The   */
/*   new approach is to rely on the FS to do the CMOS I/O, via the new  */
/*   system call CMOSTIME (which only reads the current clock value and */
/*   cannot update the CMOS clock).                                     */
/*   The original readclock.c is still available under backup.c.        */
/************************************************************************/
/*                                                                      */
/*   readclock.c                                                        */
/*                                                                      */
/*              Read the clock value from the 64 byte CMOS RAM          */
/*              area, then set system time.                             */
/*                                                                      */
/*              If the machine ID byte is 0xFC or 0xF8, the device      */
/*              /dev/mem exists and can be opened for reading,          */
/*              and no errors in the CMOS RAM are reported by the       */
/*              RTC, then the time is read from the clock RAM           */
/*              area maintained by the RTC.                             */
/*                                                                      */
/*              The clock RAM values are decoded and fed to mktime      */
/*              to make a time_t value, then stime(2) is called.        */
/*                                                                      */
/*              This fails if:                                          */
/*                                                                      */
/*              If the machine ID does not match 0xFC or 0xF8 (no       */
/*              error message.)                                         */
/*                                                                      */
/*              If the machine ID is 0xFC or 0xF8 and /dev/mem          */
/*              is missing, or cannot be accessed.                      */
/*                                                                      */
/*              If the RTC reports errors in the CMOS RAM.              */
/*                                                                      */
/************************************************************************/
/*    origination          1987-Dec-29              efth                */
/*    robustness           1990-Oct-06              C. Sylvain          */
/* incorp. B. Evans ideas  1991-Jul-06              C. Sylvain          */
/*    set time & calibrate 1992-Dec-17              Kees J. Bot         */
/*    clock timezone       1993-Oct-10              Kees J. Bot         */
/*    set CMOS clock       1994-Jun-12              Kees J. Bot         */
/*    removed set CMOS     2004-Sep-06              Jorrit N. Herder    */
/************************************************************************/

#include <minix/callnr.h>
#include <minix/config.h>
#include <minix/type.h>
#include <minix/const.h>
#include <minix/com.h>
#include <minix/syslib.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioc_cmos.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <signal.h>
#include <ibm/portio.h>
#include <ibm/cmos.h>
#include <sys/svrctl.h>

#define MAX_RETRIES     1

int nflag = 0;          /* Tell what, but don't do it. */
int y2kflag = 0;        /* Interpret 1980 as 2000 for clock with Y2K bug. */

char clocktz[128];      /* Timezone of the clock. */

#define MACH_ID_ADDR    0xFFFFE         /* BIOS Machine ID at FFFF:000E */

#define PC_AT              0xFC         /* Machine ID byte for PC/AT,
                                           PC/XT286, and PS/2 Models 50, 60 */
#define PS_386             0xF8         /* Machine ID byte for PS/2 Model 80 */

/* Manufacturers usually use the ID value of the IBM model they emulate.
 * However some manufacturers, notably HP and COMPAQ, have had different
 * ideas in the past.
 *
 * Machine ID byte information source:
 *      _The Programmer's PC Sourcebook_ by Thom Hogan,
 *      published by Microsoft Press
 */

void errmsg(char *s);
int bcd_to_dec(int n);
int dec_to_bcd(int n);
void usage(void);

#define CMOS_DEV "/dev/cmos"

PUBLIC int main(int argc, char **argv)
{
  int fd;
  struct tm time1;
  struct tm time2;
  struct tm tmnow;
  char date[64];
  time_t now, rtc;
  int i, s, mem;
  unsigned char mach_id, cmos_state;
  struct sysgetenv sysgetenv;
  message m;
  int request;


  /* Process options. */
  while (argc > 1) {
        char *p = *++argv;

        if (*p++ != '-') usage();

        while (*p != 0) {
                switch (*p++) {
                case 'n':       nflag = 1;      break;
                case '2':       y2kflag = 1;    break;
                default:        usage();
                }
        }
        argc--;
  }

#if DEAD_CODE
  /* The hardware clock may run in a different time zone, likely GMT or
   * winter time.  Select that time zone.
   */
  strcpy(clocktz, "TZ=");
  sysgetenv.key = "TZ";
  sysgetenv.keylen = 2+1;
  sysgetenv.val = clocktz+3;
  sysgetenv.vallen = sizeof(clocktz)-3;
  if (svrctl(SYSGETENV, &sysgetenv) == 0) {
        putenv(clocktz);
        tzset();
  }
#endif

  /* Read the CMOS real time clock. */
  for (i = 0; i < MAX_RETRIES; i++) {

        /* sleep, unless first iteration */
        if (i > 0) sleep(5);

        /* Open the CMOS device to read the system time. */
        if ((fd = open(CMOS_DEV, O_RDONLY)) < 0) {
                perror(CMOS_DEV);
                fprintf(stderr, "Couldn't open CMOS device.\n");
                exit(1);
        }
        request = (y2kflag) ? CIOCGETTIME : CIOCGETTIMEY2K;
        if ((s=ioctl(fd, request, (void *) &time1)) < 0) {
                perror("ioctl");
                fprintf(stderr, "Couldn't do CMOS ioctl.\n");
                exit(1);
        }
        close(fd);

        now = time(NULL);

        time1.tm_isdst = -1;    /* Do timezone calculations. */
        time2 = time1;

        rtc= mktime(&time1);    /* Transform to a time_t. */
        if (rtc != -1) {
                break;
        }

        fprintf(stderr,
"readclock: Invalid time read from CMOS RTC: %d-%02d-%02d %02d:%02d:%02d\n",
                time2.tm_year+1900, time2.tm_mon+1, time2.tm_mday,
                time2.tm_hour, time2.tm_min, time2.tm_sec);
  }
  if (i >= MAX_RETRIES) exit(1);

  /* Now set system time. */
  if (nflag) {
                printf("stime(%lu)\n", (unsigned long) rtc);
  } else {
        if (stime(&rtc) < 0) {
                errmsg( "Not allowed to set time." );
                exit(1);
        }
  }
  tmnow = *localtime(&rtc);
  if (strftime(date, sizeof(date),
                        "%a %b %d %H:%M:%S %Z %Y", &tmnow) != 0) {
        if (date[8] == '0') date[8]= ' ';
#if 0
        printf("%s [CMOS read via FS, see command/ibm/readclock.c]\n", date);
#endif
  }
  exit(0);
}

void errmsg(char *s)
{
  static char *prompt = "readclock: ";

  fprintf(stderr, "%s%s\n", prompt, s);
  prompt = "";
}


int bcd_to_dec(int n)
{
  return ((n >> 4) & 0x0F) * 10 + (n & 0x0F);
}

int dec_to_bcd(int n)
{
  return ((n / 10) << 4) | (n % 10);
}

void usage(void)
{
  fprintf(stderr, "Usage: settime [-n2]\n");
  exit(1);
}