source: trunk/third/xntp/adjtimed/adjtimed.c @ 10832

/*************************************************************************/
/* (c) Copyright Tai Jin, 1988.  All Rights Reserved.                    */
/*     Hewlett-Packard Laboratories.                                     */
/*                                                                       */
/* Permission is hereby granted for unlimited modification, use, and     */
/* distribution.  This software is made available with no warranty of    */
/* any kind, express or implied.  This copyright notice must remain      */
/* intact in all versions of this software.                              */
/*                                                                       */
/* The author would appreciate it if any bug fixes and enhancements were */
/* to be sent back to him for incorporation into future versions of this */
/* software.  Please send changes to tai@iag.hp.com or ken@sdd.hp.com.   */
/*************************************************************************/

#ifndef lint
static char RCSid[] = "adjtimed.c,v 3.1 1993/07/06 01:04:45 jbj Exp";
#endif

/*
 * Adjust time daemon.
 * This daemon adjusts the rate of the system clock a la BSD's adjtime().
 * The adjtime() routine uses SYSV messages to communicate with this daemon.
 *
 * Caveat: This emulation uses an undocumented kernel variable.  As such, it
 * cannot be guaranteed to work in future HP-UX releases.  Fortunately,
 * it will no longer be needed in HPUX 10.01 and later.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/lock.h>
#include <time.h>
#include <signal.h>
#include <nlist.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include "ntp_syslog.h"
#include "adjtime.h"

double atof();
extern int ntp_optind;
extern char *ntp_optarg;

int InitClockRate();
int AdjustClockRate();
#ifdef notdef
long GetClockRate();
#endif
int SetClockRate();
void ResetClockRate();
void Cleanup();
void Exit();

#define MILLION         1000000L

#define tvtod(tv)       ((double)(long)tv.tv_sec + \
                        ((double)tv.tv_usec / (double)MILLION))

char *progname = NULL;
int verbose = 0;
int sysdebug = 0;
static int mqid;
static double oldrate = 0.0;

int
main(argc, argv)
     int argc;
     char **argv;
{
  struct timeval remains;
  struct sigvec vec;
  MsgBuf msg;
  char ch;
  int nofork = 0;
  int fd;

  progname = argv[0];

#ifdef LOG_LOCAL6
  openlog("adjtimed", LOG_PID, LOG_LOCAL6);
#else
  openlog("adjtimed", LOG_PID);
#endif

  while ((ch = ntp_getopt(argc, argv, "hkrvdfp:")) != EOF) {
    switch (ch) {
    case 'k':
    case 'r':
      if ((mqid = msgget(KEY, 0)) != -1) {
        if (msgctl(mqid, IPC_RMID, (struct msqid_ds *)0) == -1) {
          msyslog(LOG_ERR, "remove old message queue: %m");
          perror("adjtimed: remove old message queue");
          exit(1);
        }
      }

      if (ch == 'k')
        exit(0);

      break;

    case 'v':
      ++verbose, nofork = 1;
      break;

    case 'd':
      ++sysdebug;
      break;

    case 'f':
      nofork = 1;
      break;

    case 'p':
      fputs("adjtimed: -p option ignored\n", stderr);
      break;

    default:
      puts("usage: adjtimed -hkrvdf");
      puts("-h\thelp");
      puts("-k\tkill existing adjtimed, if any");
      puts("-r\trestart (kills existing adjtimed, if any)");
      puts("-v\tdebug output (repeat for more output)");
      puts("-d\tsyslog output (repeat for more output)");
      puts("-f\tno fork");
      msyslog(LOG_ERR, "usage error");
      exit(1);
    } /* switch */
  } /* while */

  if (!nofork) {
    switch (fork()) {
    case 0:
      close(fileno(stdin));
      close(fileno(stdout));
      close(fileno(stderr));

#ifdef TIOCNOTTY
      if ((fd = open("/dev/tty")) != -1) {
        ioctl(fd, TIOCNOTTY, 0);
        close(fd);
      }
#else
      setpgrp();
#endif
      break;

    case -1:
      msyslog(LOG_ERR, "fork: %m");
      perror("adjtimed: fork");
      exit(1);

    default:
      exit(0);
    } /* switch */
  } /* if */

  if (nofork) {
    setvbuf(stdout, NULL, _IONBF, BUFSIZ);
    setvbuf(stderr, NULL, _IONBF, BUFSIZ);
  }

  msyslog(LOG_INFO, "started");
  if (verbose) printf("adjtimed: started\n");

  if (InitClockRate() == -1)
    Exit(2);

  (void)signal(SIGHUP, SIG_IGN);
  (void)signal(SIGINT, SIG_IGN);
  (void)signal(SIGQUIT, SIG_IGN);
  (void)signal(SIGTERM, Cleanup);

  vec.sv_handler = ResetClockRate;
  vec.sv_flags = 0;
  vec.sv_mask = ~0;
  sigvector(SIGALRM, &vec, (struct sigvec *)0);

  if (msgget(KEY, IPC_CREAT|IPC_EXCL) == -1) {
    if (errno == EEXIST) {
      msyslog(LOG_ERR, "message queue already exists, use -r to remove it");
      fputs("adjtimed: message queue already exists, use -r to remove it\n",
                stderr);
      Exit(1);
    }

    msyslog(LOG_ERR, "create message queue: %m");
    perror("adjtimed: create message queue");
    Exit(1);
  }

  if ((mqid = msgget(KEY, 0)) == -1) {
    msyslog(LOG_ERR, "get message queue id: %m");
    perror("adjtimed: get message queue id");
    Exit(1);
  }
  
  /* Lock process in memory to improve response time */
  if (plock(PROCLOCK)) {
      msyslog(LOG_ERR, "plock: %m");
      perror("adjtimed: plock");
      Cleanup();
  }

  /* Also raise process priority.
   * If we do not get run when we want, this leads to bad timekeeping
   * and "Previous time adjustment didn't complete" gripes from xntpd.
   */
  if (nice(-10) == -1) {
      msyslog(LOG_ERR, "nice: %m");
      perror("adjtimed: nice");
      Cleanup();
  }

  for (;;) {
    if (msgrcv(mqid, &msg.msgp, MSGSIZE, CLIENT, 0) == -1) {
      if (errno == EINTR) continue;
      msyslog(LOG_ERR, "read message: %m");
      perror("adjtimed: read message");
      Cleanup();
    }

    switch (msg.msgb.code) {
    case DELTA1:
    case DELTA2:
      AdjustClockRate(&msg.msgb.tv, &remains);

      if (msg.msgb.code == DELTA2) {
        msg.msgb.tv = remains;
        msg.msgb.mtype = SERVER;

        while (msgsnd(mqid, &msg.msgp, MSGSIZE, 0) == -1) {
          if (errno == EINTR) continue;
          msyslog(LOG_ERR, "send message: %m");
          perror("adjtimed: send message");
          Cleanup();
        }
      }

      if (remains.tv_sec + remains.tv_usec != 0L) {
        if (verbose) {
          printf("adjtimed: previous correction remaining %.6fs\n",
                        tvtod(remains));
        }
        if (sysdebug) {
          msyslog(LOG_INFO, "previous correction remaining %.6fs",
                        tvtod(remains));
        }
      }
      break;

    default:
      fprintf(stderr, "adjtimed: unknown message code %d\n", msg.msgb.code);
      msyslog(LOG_ERR, "unknown message code %d", msg.msgb.code);
    } /* switch */
  } /* loop */
} /* main */

/*
 * Default clock rate (old_tick).
 */
#define DEFAULT_RATE    (MILLION / HZ)
#define UNKNOWN_RATE    0L
#define TICK_ADJ        5       /* standard adjustment rate, microsec/tick */

static long default_rate = DEFAULT_RATE;
static long tick_rate = HZ;     /* ticks per sec */
static long slew_rate = TICK_ADJ * HZ; /* in microsec/sec */

int
AdjustClockRate(delta, olddelta)
     register struct timeval *delta, *olddelta;
{
  register long rate, dt, leftover;
  struct itimerval period, remains;
 
  dt = (delta->tv_sec * MILLION) + delta->tv_usec;

  if (verbose)
    printf("adjtimed: new correction %.6fs\n", (double)dt / (double)MILLION);
  if (sysdebug)
    msyslog(LOG_INFO, "new correction %.6fs", (double)dt / (double)MILLION);
  if (verbose > 2) printf("adjtimed: leftover %ldus\n", leftover);
  if (sysdebug > 2) msyslog(LOG_INFO, "leftover %ldus", leftover);
  rate = dt;

/*
 * Apply a slew rate of slew_rate over a period of dt/slew_rate seconds.
 */
  if (dt > 0) {
    rate = slew_rate;
  } else {
    rate = -slew_rate;
    dt = -dt;
  }
  period.it_value.tv_sec = dt / slew_rate;
  period.it_value.tv_usec = (dt % slew_rate) * (MILLION / slew_rate);
/*
 * Note: we assume the kernel will convert the specified period into ticks
 * using the modified clock rate rather than an assumed nominal clock rate,
 * and therefore will generate the timer interrupt after the specified
 * number of true seconds, not skewed seconds.
 */

  if (verbose > 1)
    printf("adjtimed: will be complete in %lds %ldus\n",
           period.it_value.tv_sec, period.it_value.tv_usec);
  if (sysdebug > 1)
    msyslog(LOG_INFO, "will be complete in %lds %ldus",
           period.it_value.tv_sec, period.it_value.tv_usec);
/*
 * adjust the clock rate
 */
  if (dt) {
    if (SetClockRate((rate / tick_rate) + default_rate) == -1) {
      msyslog(LOG_ERR, "set clock rate: %m");
      perror("adjtimed: set clock rate");
    }
  }
/*
 * start the timer
 * (do this after changing the rate because the period has been rounded down)
 */
  period.it_interval.tv_sec = period.it_interval.tv_usec = 0L;
  setitimer(ITIMER_REAL, &period, &remains);
/*
 * return old delta
 */
  if (olddelta) {
    dt = ((remains.it_value.tv_sec * MILLION) + remains.it_value.tv_usec) *
                oldrate;
    olddelta->tv_sec = dt / MILLION;
    olddelta->tv_usec = dt - (olddelta->tv_sec * MILLION); 
  }

  oldrate = (double)rate / (double)MILLION;
  return(0);
} /* AdjustClockRate */

static struct nlist nl[] = {
#ifdef hp9000s800
#ifdef PRE7_0
  { "tick" },
#else
  { "old_tick" },
#endif
#else
  { "_old_tick" },
#endif
  { "" }
};

static int kmem;

/*
 * The return value is the clock rate in old_tick units or -1 if error.
 */
long
GetClockRate()
{
  long rate, mask;

  if (lseek(kmem, (long)nl[0].n_value, 0) == -1L)
    return (-1L);

  mask = sigblock(sigmask(SIGALRM));

  if (read(kmem, (caddr_t)&rate, sizeof(rate)) != sizeof(rate))
    rate = UNKNOWN_RATE;

  sigsetmask(mask);
  return (rate);
} /* GetClockRate */

/*
 * The argument is the new rate in old_tick units.
 */
int
SetClockRate(rate)
     long rate;
{
  long mask;

  if (lseek(kmem, (long)nl[0].n_value, 0) == -1L)
    return (-1);

  mask = sigblock(sigmask(SIGALRM));

  if (write(kmem, (caddr_t)&rate, sizeof(rate)) != sizeof(rate)) {
    sigsetmask(mask);
    return (-1);
  }

  sigsetmask(mask);

  if (rate != default_rate) {
    if (verbose > 3) {
      printf("adjtimed: clock rate (%lu) %ldus/s\n", rate,
                (rate - default_rate) * tick_rate);
    }
    if (sysdebug > 3) {
      msyslog(LOG_INFO, "clock rate (%lu) %ldus/s", rate,
                (rate - default_rate) * tick_rate);
    }
  }

  return (0);
} /* SetClockRate */

int
InitClockRate()
{
  if ((kmem = open("/dev/kmem", O_RDWR)) == -1) {
    msyslog(LOG_ERR, "open(/dev/kmem): %m");
    perror("adjtimed: open(/dev/kmem)");
    return (-1);
  }

  nlist("/hp-ux", nl);

  if (nl[0].n_type == 0) {
    fputs("adjtimed: /hp-ux has no symbol table\n", stderr);
    msyslog(LOG_ERR, "/hp-ux has no symbol table");
    return (-1);
  }
/*
 * Set the default to the system's original value
 */
  default_rate = GetClockRate();
  if (default_rate == UNKNOWN_RATE) default_rate = DEFAULT_RATE;
  tick_rate = (MILLION / default_rate);
  slew_rate = TICK_ADJ * tick_rate;

  return (0);
} /* InitClockRate */

/*
 * Reset the clock rate to the default value.
 */
void
ResetClockRate()
{
  struct itimerval it;

  it.it_value.tv_sec = it.it_value.tv_usec = 0L;
  setitimer(ITIMER_REAL, &it, (struct itimerval *)0);

  if (verbose > 2) puts("adjtimed: resetting the clock");
  if (sysdebug > 2) msyslog(LOG_INFO, "resetting the clock");

  if (GetClockRate() != default_rate) {
    if (SetClockRate(default_rate) == -1) {
      msyslog(LOG_ERR, "set clock rate: %m");
      perror("adjtimed: set clock rate");
    }
  }

  oldrate = 0.0;
} /* ResetClockRate */

void
Cleanup()
{
  ResetClockRate();

  if (msgctl(mqid, IPC_RMID, (struct msqid_ds *)0) == -1) {
    if (errno != EINVAL) {
      msyslog(LOG_ERR, "remove message queue: %m");
      perror("adjtimed: remove message queue");
    }
  }

  Exit(2);
} /* Cleanup */

void
Exit(status)
     int status;
{
  msyslog(LOG_ERR, "terminated");
  closelog();
  if (kmem != -1) close(kmem);
  exit(status);
} /* Exit */