7
* MPE lacks adjtime(), so we define our own. But note that time slewing has
8
* a sub-second accuracy bug documented in SR 5003462838 which prevents ntpd
9
* from being able to maintain clock synch. Because of the bug, this adjtime()
10
* implementation as used by ntpd has a side-effect of screwing up the hardware
11
* PDC clock, which will need to be reset with a reboot.
13
* This problem affects all versions of MPE at the time of this writing (when
14
* MPE/iX 7.0 is the most current). It only causes bad things to happen when
15
* doing continuous clock synchronization with ntpd; note that you CAN run ntpd
16
* with "disable ntp" in ntp.conf if you wish to provide a time server.
18
* The one-time clock adjustment functionality of ntpdate and ntp_timeset can
19
* be used without screwing up the PDC clock.
24
int adjtime(struct timeval *delta, struct timeval *olddelta);
26
int adjtime(struct timeval *delta, struct timeval *olddelta)
29
/* Documented, supported MPE system intrinsics. */
31
extern void GETPRIVMODE(void);
32
extern void GETUSERMODE(void);
34
/* Undocumented, unsupported MPE internal functions. */
36
extern long long current_correction_usecs(void);
37
extern long long get_time(void);
38
extern void get_time_change_info(long long *, char *, char *);
39
extern long long pdc_time(int *);
40
extern void set_time_correction(long long, int, int);
41
extern long long ticks_to_micro(long long);
43
long long big_sec, big_usec, new_correction = 0LL;
44
long long prev_correction;
47
/* Adjustment required. Convert delta to 64-bit microseconds. */
48
big_sec = (long)delta->tv_sec;
49
big_usec = delta->tv_usec;
50
new_correction = (big_sec * 1000000LL) + big_usec;
55
/* Determine how much of a previous correction (if any) we're interrupting. */
56
prev_correction = current_correction_usecs();
59
/* Adjustment required. */
62
/* Speculative code disabled until bug SR 5003462838 is fixed. This bug
63
prevents accurate time slewing, and indeed renders ntpd inoperable. */
65
if (prev_correction != 0LL) {
66
/* A previous adjustment did not complete. Since the PDC UTC clock was
67
immediately jumped at the start of the previous adjustment, we must
68
explicitly reset it to the value of the MPE local time clock minus the
71
char pwf_since_boot, recover_pwf_time;
72
long long offset_ticks, offset_usecs, pdc_usecs_current, pdc_usecs_wanted;
75
get_time_change_info(&offset_ticks, &pwf_since_boot, &recover_pwf_time);
76
offset_usecs = ticks_to_micro(offset_ticks);
77
pdc_usecs_wanted = get_time() - offset_usecs;
78
pdc_usecs_current = pdc_time(&hpe_status);
80
/* Force new PDC time by starting an extra correction. */
81
set_time_correction(pdc_usecs_wanted - pdc_usecs_current,0,1);
85
/* Immediately jump the PDC time to the new value, and then initiate a
86
gradual MPE time correction slew. */
87
set_time_correction(new_correction,0,1);
92
if (olddelta != NULL) {
93
/* Caller wants to know remaining amount of previous correction. */
94
(long)olddelta->tv_sec = prev_correction / 1000000LL;
95
olddelta->tv_usec = prev_correction % 1000000LL;
102
#ifdef NEED_HPUX_ADJTIME
103
/*************************************************************************/
104
/* (c) Copyright Tai Jin, 1988. All Rights Reserved. */
105
/* Hewlett-Packard Laboratories. */
107
/* Permission is hereby granted for unlimited modification, use, and */
108
/* distribution. This software is made available with no warranty of */
109
/* any kind, express or implied. This copyright notice must remain */
110
/* intact in all versions of this software. */
112
/* The author would appreciate it if any bug fixes and enhancements were */
113
/* to be sent back to him for incorporation into future versions of this */
114
/* software. Please send changes to tai@iag.hp.com or ken@sdd.hp.com. */
115
/*************************************************************************/
120
* 9 Jul 94 David L. Mills, Unibergity of Delabunch
121
* Implemented variable threshold to limit age of
122
* corrections; reformatted code for readability.
126
static char RCSid[] = "adjtime.c,v 3.1 1993/07/06 01:04:42 jbj Exp";
129
#include <sys/types.h>
136
#define abs(x) ((x) < 0 ? -(x) : (x))
139
* The following paramters are appropriate for an NTP adjustment
140
* interval of one second.
142
#define ADJ_THRESH 200 /* initial threshold */
143
#define ADJ_DELTA 4 /* threshold decrement */
145
static long adjthresh; /* adjustment threshold */
146
static long saveup; /* corrections accumulator */
149
* clear_adjtime - reset accumulator and threshold variables
155
adjthresh = ADJ_THRESH;
159
* adjtime - hp-ux copout of the standard Unix adjtime() system call
163
register struct timeval *delta,
164
register struct timeval *olddelta
167
struct timeval newdelta;
170
* Corrections greater than one second are done immediately.
173
adjthresh = ADJ_THRESH;
175
return(_adjtime(delta, olddelta));
179
* Corrections less than one second are accumulated until
180
* tripping a threshold, which is initially set at ADJ_THESH and
181
* reduced in ADJ_DELTA steps to zero. The idea here is to
182
* introduce large corrections quickly, while making sure that
183
* small corrections are introduced without excessive delay. The
184
* idea comes from the ARPAnet routing update algorithm.
186
saveup += delta->tv_usec;
187
if (abs(saveup) >= adjthresh) {
188
adjthresh = ADJ_THRESH;
190
newdelta.tv_usec = saveup;
192
return(_adjtime(&newdelta, olddelta));
194
adjthresh -= ADJ_DELTA;
198
* While nobody uses it, return the residual before correction,
199
* as per Unix convention.
202
olddelta->tv_sec = olddelta->tv_usec = 0;
207
* _adjtime - does the actual work
211
register struct timeval *delta,
212
register struct timeval *olddelta
217
register MsgBuf *msgp = &msg;
220
* Get the key to the adjtime message queue (note that we must
221
* get it every time because the queue might have been removed
224
if ((mqid = msgget(KEY, 0)) == -1)
226
msgp->msgb.mtype = CLIENT;
227
msgp->msgb.tv = *delta;
229
msgp->msgb.code = DELTA2;
231
msgp->msgb.code = DELTA1;
234
* Tickle adjtimed and snatch residual, if indicated. Lots of
235
* fanatic error checking here.
237
if (msgsnd(mqid, &msgp->msgp, MSGSIZE, 0) == -1)
240
if (msgrcv(mqid, &msgp->msgp, MSGSIZE, SERVER, 0) == -1)
242
*olddelta = msgp->msgb.tv;
248
# if NEED_QNX_ADJTIME
250
* Emulate adjtime() using QNX ClockAdjust().
251
* Chris Burghart <burghart@atd.ucar.edu>, 11/2001
253
* This is a *very* simple implementation of adjtime() for QNX.
254
* ClockAdjust() is used to tweak the system clock by about +- 1/10
255
* of its current clock period per tick until the desired delta is
260
# include <sys/neutrino.h>
261
# include <sys/time.h>
263
# include <ntp_stdlib.h>
266
adjtime (struct timeval *delta, struct timeval *olddelta)
269
double delta_nsec_old;
270
struct _clockadjust adj;
271
struct _clockadjust oldadj;
273
* How many nanoseconds are we adjusting?
275
delta_nsec = delta->tv_sec * 1e9 + delta->tv_usec * 1000;
277
* Build the adjust structure and call ClockAdjust()
281
struct _clockperiod period;
286
* Get the current clock period (nanoseconds)
288
if (ClockPeriod (CLOCK_REALTIME, 0, &period, 0) < 0)
292
* Set the adjust increment to approximately 1/10 timer period per
295
count = 1 + (long)(fabs(10 * delta_nsec / period.nsec));
296
increment = (long)(delta_nsec / count);
298
adj.tick_nsec_inc = increment;
299
adj.tick_count = count;
303
adj.tick_nsec_inc = 0;
307
if (ClockAdjust (CLOCK_REALTIME, &adj, &oldadj) < 0)
313
delta_nsec_old = oldadj.tick_count * oldadj.tick_nsec_inc;
314
olddelta->tv_sec = (int)(delta_nsec_old / 1e9);
315
olddelta->tv_usec = (int)((delta_nsec_old - 1.0e9 * olddelta->tv_sec) /
320
# else /* no special adjtime() needed */
added
removed
libntp/adjtime.c
