127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2009
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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SHM refclock driver.
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*/
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#include "config.h"
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#include "sysincl.h"
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#include "refclock.h"
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#include "logging.h"
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#include "util.h"
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#define SHMKEY 0x4e545030
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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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int clockTimeStampNSec;
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int receiveTimeStampNSec;
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int dummy[8];
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};
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static int shm_initialise(RCL_Instance instance) {
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int id, param, perm;
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char *s;
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struct shmTime *shm;
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param = atoi(RCL_GetDriverParameter(instance));
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s = RCL_GetDriverOption(instance, "perm");
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perm = s ? strtol(s, NULL, 8) & 0777 : 0600;
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id = shmget(SHMKEY + param, sizeof (struct shmTime), IPC_CREAT | perm);
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if (id == -1) {
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LOG_FATAL(LOGF_Refclock, "shmget() failed");
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return 0;
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}
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shm = (struct shmTime *)shmat(id, 0, 0);
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if ((long)shm == -1) {
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LOG_FATAL(LOGF_Refclock, "shmat() failed");
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return 0;
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}
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RCL_SetDriverData(instance, shm);
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return 1;
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}
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static void shm_finalise(RCL_Instance instance)
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{
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shmdt(RCL_GetDriverData(instance));
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}
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static int shm_poll(RCL_Instance instance)
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{
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struct timeval tv;
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struct shmTime t, *shm;
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double offset;
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shm = (struct shmTime *)RCL_GetDriverData(instance);
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t = *shm;
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if ((t.mode == 1 && t.count != shm->count) ||
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!(t.mode == 0 || t.mode == 1) || !t.valid) {
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DEBUG_LOG(LOGF_Refclock, "SHM sample ignored mode=%d count=%d valid=%d",
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t.mode, t.count, t.valid);
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return 0;
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}
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shm->valid = 0;
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tv.tv_sec = t.receiveTimeStampSec;
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tv.tv_usec = t.receiveTimeStampUSec;
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offset = t.clockTimeStampSec - t.receiveTimeStampSec;
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if (t.clockTimeStampNSec / 1000 == t.clockTimeStampUSec &&
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t.receiveTimeStampNSec / 1000 == t.receiveTimeStampUSec)
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offset += (t.clockTimeStampNSec - t.receiveTimeStampNSec) * 1e-9;
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else
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offset += (t.clockTimeStampUSec - t.receiveTimeStampUSec) * 1e-6;
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return RCL_AddSample(instance, &tv, offset, t.leap);
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}
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RefclockDriver RCL_SHM_driver = {
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shm_initialise,
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shm_finalise,
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shm_poll
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};
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