261 lines
6.1 KiB
C
261 lines
6.1 KiB
C
/*
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* sht.c - Testprogram for shared memory refclock
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* read/write shared memory segment; see usage
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*/
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#include "config.h"
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#ifndef SYS_WINNT
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#include <sys/types.h>
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#include <sys/ipc.h>
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#include <sys/shm.h>
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#include <stdio.h>
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#include <time.h>
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#include <unistd.h>
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#include <stdlib.h>
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#else
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#include <windows.h>
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#include <time.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <iostream.h>
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#define sleep(x) Sleep(x*1000)
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#endif
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#include <assert.h>
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struct shmTime {
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int mode; /* 0 - if valid set
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* use values,
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* clear valid
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* 1 - if valid set
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* if count before and after read of values is equal,
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* use values
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* clear valid
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*/
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volatile int count;
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time_t clockTimeStampSec;
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int clockTimeStampUSec;
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time_t receiveTimeStampSec;
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int receiveTimeStampUSec;
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int leap;
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int precision;
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int nsamples;
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volatile int valid;
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unsigned clockTimeStampNSec; /* Unsigned ns timestamps */
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unsigned receiveTimeStampNSec; /* Unsigned ns timestamps */
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};
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static struct shmTime *
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getShmTime (
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int unit
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)
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{
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#ifndef SYS_WINNT
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int shmid=shmget (0x4e545030+unit, sizeof (struct shmTime), IPC_CREAT|0777);
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if (shmid==-1) {
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perror ("shmget");
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exit (1);
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}
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else {
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struct shmTime *p=(struct shmTime *)shmat (shmid, 0, 0);
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if ((int)(long)p==-1) {
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perror ("shmat");
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p=0;
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}
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assert (p!=0);
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return p;
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}
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#else
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char buf[10];
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LPSECURITY_ATTRIBUTES psec=0;
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snprintf (buf, sizeof(buf), "NTP%d", unit);
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SECURITY_DESCRIPTOR sd;
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SECURITY_ATTRIBUTES sa;
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HANDLE shmid;
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assert (InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION));
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assert (SetSecurityDescriptorDacl(&sd,1,0,0));
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sa.nLength=sizeof (SECURITY_ATTRIBUTES);
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sa.lpSecurityDescriptor=&sd;
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sa.bInheritHandle=0;
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shmid=CreateFileMapping ((HANDLE)0xffffffff, 0, PAGE_READWRITE,
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psec, sizeof (struct shmTime),buf);
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if (!shmid) {
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shmid=CreateFileMapping ((HANDLE)0xffffffff, 0, PAGE_READWRITE,
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0, sizeof (struct shmTime),buf);
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cout <<"CreateFileMapping with psec!=0 failed"<<endl;
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}
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if (!shmid) {
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char mbuf[1000];
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FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM,
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0, GetLastError (), 0, mbuf, sizeof (mbuf), 0);
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int x=GetLastError ();
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cout <<"CreateFileMapping "<<buf<<":"<<mbuf<<endl;
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exit (1);
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}
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else {
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struct shmTime *p=(struct shmTime *) MapViewOfFile (shmid,
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FILE_MAP_WRITE, 0, 0, sizeof (struct shmTime));
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if (p==0) {
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char mbuf[1000];
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FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM,
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0, GetLastError (), 0, mbuf, sizeof (mbuf), 0);
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cout <<"MapViewOfFile "<<buf<<":"<<mbuf<<endl;
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exit (1);
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}
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return p;
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}
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return 0;
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#endif
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}
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int
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main (
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int argc,
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char *argv[]
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)
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{
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volatile struct shmTime *p;
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int unit;
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char *argp;
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if (argc<=1) {
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usage:
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printf ("usage: %s [uu:]{r[c][l]|w|snnn}\n",argv[0]);
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printf (" uu use clock unit uu (default: 2)\n");
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printf (" r read shared memory\n");
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printf (" c clear valid-flag\n");
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printf (" l loop (so, rcl will read and clear in a loop\n");
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printf (" w write shared memory with current time\n");
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printf (" snnnn set nsamples to nnn\n");
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printf (" lnnnn set leap to nnn\n");
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printf (" pnnnn set precision to -nnn\n");
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exit (0);
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}
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srand(time(NULL));
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unit = strtoul(argv[1], &argp, 10);
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if (argp == argv[1])
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unit = 2;
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else if (*argp == ':')
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argp++;
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else
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goto usage;
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p=getShmTime(unit);
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switch (*argp) {
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case 's':
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p->nsamples=atoi(argp+1);
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break;
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case 'l':
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p->leap=atoi(argp+1);
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break;
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case 'p':
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p->precision=-atoi(argp+1);
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break;
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case 'r': {
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int clear=0;
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int loop=0;
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printf ("reader\n");
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while (*++argp) {
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switch (*argp) {
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case 'l': loop=1; break;
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case 'c': clear=1; break;
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default : goto usage;
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}
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}
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again:
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printf ("mode=%d, count=%d, clock=%ld.%09u, rec=%ld.%09u,\n",
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p->mode,p->count,
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(long)p->clockTimeStampSec,p->clockTimeStampNSec,
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(long)p->receiveTimeStampSec,p->receiveTimeStampNSec);
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printf (" leap=%d, precision=%d, nsamples=%d, valid=%d\n",
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p->leap, p->precision, p->nsamples, p->valid);
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if (!p->valid)
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printf ("***\n");
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if (clear) {
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p->valid=0;
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printf ("cleared\n");
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}
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if (loop) {
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sleep (1);
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goto again;
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}
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break;
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}
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case 'w': {
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/* To show some life action, we read the system
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* clock and use a bit of fuzz from 'random()' to get a
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* bit of wobbling into the values (so we can observe a
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* certain jitter!)
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*/
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time_t clk_sec, rcv_sec;
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u_int clk_frc, rcv_frc;
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#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_REALTIME)
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/* Here we have a high-resolution system clock, and
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* we're not afraid to use it!
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*/
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struct timespec tmptime;
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if (0 == clock_gettime(CLOCK_REALTIME, &tmptime)) {
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rcv_sec = tmptime.tv_sec;
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rcv_frc = (u_int)tmptime.tv_nsec;
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}
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else
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#endif
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{
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time(&rcv_sec);
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rcv_frc = (u_int)random() % 1000000000u;
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}
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/* add a wobble of ~3.5msec to the clock time */
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clk_sec = rcv_sec;
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clk_frc = rcv_frc + (u_int)(random()%7094713 - 3547356);
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/* normalise result -- the SHM driver is picky! */
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while ((int)clk_frc < 0) {
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clk_frc += 1000000000;
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clk_sec -= 1;
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}
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while ((int)clk_frc >= 1000000000) {
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clk_frc -= 1000000000;
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clk_sec += 1;
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}
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/* Most 'real' time sources would create a clock
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* (reference) time stamp where the fraction is zero,
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* but that's not an actual requirement. So we show how
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* to deal with the time stamps in general; changing the
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* behaviour for cases where the fraction of the
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* clock time is zero should be trivial.
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*/
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printf ("writer\n");
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p->mode=0;
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if (!p->valid) {
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p->clockTimeStampSec = clk_sec;
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p->clockTimeStampUSec = clk_frc / 1000; /* truncate! */
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p->clockTimeStampNSec = clk_frc;
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p->receiveTimeStampSec = rcv_sec;
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p->receiveTimeStampUSec = rcv_frc / 1000; /* truncate! */
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p->receiveTimeStampNSec = rcv_frc;
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printf ("%ld.%09u %ld.%09u\n",
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(long)p->clockTimeStampSec , p->clockTimeStampNSec ,
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(long)p->receiveTimeStampSec, p->receiveTimeStampNSec);
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p->valid=1;
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}
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else {
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printf ("p->valid still set\n"); /* not an error! */
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}
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break;
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}
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default:
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break;
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}
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return 0;
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}
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