301 lines
7.0 KiB
C
301 lines
7.0 KiB
C
/*
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* refclock_shm - clock driver for utc via shared memory
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* - under construction -
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* To add new modes: Extend or union the shmTime-struct. Do not
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* extend/shrink size, because otherwise existing implementations
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* will specify wrong size of shared memory-segment
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* PB 18.3.97
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#if defined(REFCLOCK) && defined(CLOCK_SHM)
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#include "ntpd.h"
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#undef fileno
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#include "ntp_io.h"
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#undef fileno
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#include "ntp_refclock.h"
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#undef fileno
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#include "ntp_unixtime.h"
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#undef fileno
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#include "ntp_stdlib.h"
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#undef fileno
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#include <ctype.h>
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#undef fileno
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#ifndef SYS_WINNT
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# include <sys/ipc.h>
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# include <sys/shm.h>
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# include <assert.h>
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# include <unistd.h>
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# include <stdio.h>
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#endif
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/*
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* This driver supports a reference clock attached thru shared memory
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*/
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/*
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* SHM interface definitions
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*/
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#define PRECISION (-1) /* precision assumed (0.5 s) */
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#define REFID "SHM" /* reference ID */
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#define DESCRIPTION "SHM/Shared memory interface"
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#define NSAMPLES 3 /* stages of median filter */
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/*
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* Function prototypes
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*/
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static int shm_start (int, struct peer *);
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static void shm_shutdown (int, struct peer *);
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static void shm_poll (int unit, struct peer *);
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/*
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* Transfer vector
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*/
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struct refclock refclock_shm = {
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shm_start, /* start up driver */
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shm_shutdown, /* shut down driver */
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shm_poll, /* transmit poll message */
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noentry, /* not used */
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noentry, /* initialize driver (not used) */
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noentry, /* not used */
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NOFLAGS /* not used */
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};
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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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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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int valid;
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int dummy[10];
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};
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struct shmTime *getShmTime (int unit) {
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#ifndef SYS_WINNT
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int shmid=0;
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assert (unit<10); /* MAXUNIT is 4, so should never happen */
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shmid=shmget (0x4e545030+unit, sizeof (struct shmTime),
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IPC_CREAT|(unit<2?0700:0777));
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if (shmid==-1) { /*error */
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msyslog(LOG_ERR,"SHM shmget (unit %d): %s",unit,strerror(errno));
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return 0;
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}
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else { /* no error */
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struct shmTime *p=(struct shmTime *)shmat (shmid, 0, 0);
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if ((int)(long)p==-1) { /* error */
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msyslog(LOG_ERR,"SHM shmat (unit %d): %s",unit,strerror(errno));
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return 0;
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}
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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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HANDLE shmid=0;
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SECURITY_DESCRIPTOR sd;
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SECURITY_ATTRIBUTES sa;
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sprintf (buf,"NTP%d",unit);
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if (unit>=2) { /* world access */
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if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION)) {
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msyslog(LOG_ERR,"SHM InitializeSecurityDescriptor (unit %d): %m",unit);
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return 0;
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}
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if (!SetSecurityDescriptorDacl(&sd,1,0,0)) {
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msyslog(LOG_ERR,"SHM SetSecurityDescriptorDacl (unit %d): %m",unit);
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return 0;
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}
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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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psec=&sa;
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}
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shmid=CreateFileMapping ((HANDLE)0xffffffff, psec, PAGE_READWRITE,
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0, sizeof (struct shmTime),buf);
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if (!shmid) { /*error*/
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char buf[1000];
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FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM,
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0, GetLastError (), 0, buf, sizeof (buf), 0);
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msyslog(LOG_ERR,"SHM CreateFileMapping (unit %d): %s",unit,buf);
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return 0;
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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) { /*error*/
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char buf[1000];
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FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM,
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0, GetLastError (), 0, buf, sizeof (buf), 0);
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msyslog(LOG_ERR,"SHM MapViewOfFile (unit %d): %s",unit,buf);
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return 0;
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}
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return p;
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}
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#endif
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return 0;
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}
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/*
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* shm_start - attach to shared memory
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*/
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static int
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shm_start(
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int unit,
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struct peer *peer
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)
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{
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struct refclockproc *pp;
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pp = peer->procptr;
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pp->io.clock_recv = noentry;
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pp->io.srcclock = (caddr_t)peer;
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pp->io.datalen = 0;
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pp->io.fd = -1;
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pp->unitptr = (caddr_t)getShmTime(unit);
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/*
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* Initialize miscellaneous peer variables
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*/
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memcpy((char *)&pp->refid, REFID, 4);
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if (pp->unitptr!=0) {
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((struct shmTime*)pp->unitptr)->precision=PRECISION;
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peer->precision = ((struct shmTime*)pp->unitptr)->precision;
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((struct shmTime*)pp->unitptr)->valid=0;
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((struct shmTime*)pp->unitptr)->nsamples=NSAMPLES;
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pp->clockdesc = DESCRIPTION;
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return (1);
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}
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else {
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return 0;
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}
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}
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/*
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* shm_shutdown - shut down the clock
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*/
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static void
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shm_shutdown(
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int unit,
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struct peer *peer
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)
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{
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register struct shmTime *up;
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struct refclockproc *pp;
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pp = peer->procptr;
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up = (struct shmTime *)pp->unitptr;
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#ifndef SYS_WINNT
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shmdt (up);
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#else
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UnmapViewOfFile (up);
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#endif
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}
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/*
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* shm_poll - called by the transmit procedure
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*/
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static void
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shm_poll(
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int unit,
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struct peer *peer
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)
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{
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register struct shmTime *up;
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struct refclockproc *pp;
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/*
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* This is the main routine. It snatches the time from the shm
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* board and tacks on a local timestamp.
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*/
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pp = peer->procptr;
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up = (struct shmTime*)pp->unitptr;
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if (up==0) { /* try to map again - this may succeed if meanwhile some-
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body has ipcrm'ed the old (unaccessible) shared mem
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segment */
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pp->unitptr = (caddr_t)getShmTime(unit);
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up = (struct shmTime*)pp->unitptr;
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}
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if (up==0) {
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refclock_report(peer, CEVNT_FAULT);
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return;
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}
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if (up->valid) {
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struct timeval tvr;
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struct timeval tvt;
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struct tm *t;
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int ok=1;
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switch (up->mode) {
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case 0: {
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tvr.tv_sec=up->receiveTimeStampSec;
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tvr.tv_usec=up->receiveTimeStampUSec;
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tvt.tv_sec=up->clockTimeStampSec;
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tvt.tv_usec=up->clockTimeStampUSec;
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}
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break;
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case 1: {
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int cnt=up->count;
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tvr.tv_sec=up->receiveTimeStampSec;
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tvr.tv_usec=up->receiveTimeStampUSec;
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tvt.tv_sec=up->clockTimeStampSec;
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tvt.tv_usec=up->clockTimeStampUSec;
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ok=(cnt==up->count);
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}
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break;
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default:
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msyslog (LOG_ERR, "SHM: bad mode found in shared memory: %d",up->mode);
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}
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up->valid=0;
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if (ok) {
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TVTOTS(&tvr,&pp->lastrec);
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pp->lastrec.l_ui += JAN_1970;
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/* pp->lasttime = current_time; */
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pp->polls++;
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t=gmtime (&tvt.tv_sec);
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pp->day=t->tm_yday+1;
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pp->hour=t->tm_hour;
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pp->minute=t->tm_min;
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pp->second=t->tm_sec;
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pp->msec=0;
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pp->usec=tvt.tv_usec;
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peer->precision=up->precision;
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pp->leap=up->leap;
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}
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else {
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refclock_report(peer, CEVNT_FAULT);
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msyslog (LOG_NOTICE, "SHM: access clash in shared memory");
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return;
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}
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}
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else {
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refclock_report(peer, CEVNT_TIMEOUT);
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msyslog (LOG_NOTICE, "SHM: no new value found in shared memory");
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return;
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}
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if (!refclock_process(pp)) {
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refclock_report(peer, CEVNT_BADTIME);
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return;
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}
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refclock_receive(peer);
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}
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#else
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int refclock_shm_bs;
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#endif /* REFCLOCK */
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