Separate ntpd support from chrony support, step 1.

ntp_offset becomes time_offset. There is a new config symbol CHRONY_ENABLE;
most time service code is npw controlled by TIMESERVICE_ENABLE.  The
file ntpshm.c becomes timeexport.c

This change is not complete. More disentanglement has to be done inside
timeexport.c itself; at the moment enabling one but not both of
ntpshm or chrony will probably break its compile.  The point of getting
this commit out is so Gary will see the new baseline code ASAP.

All regression tests pass.

1 files changed, 0 insertions, 505 deletions

diff --git a/ntpshm.c b/ntpshm.c
deleted file mode 100644
index 5fe96af3..00000000
--- a/ntpshm.c
+++ /dev/null
@@ -1,505 +0,0 @@
-/*
- * ntpshm.c - put time information in SHM segment for xntpd, or to chrony
- *
- * struct shmTime and getShmTime from file in the xntp distribution:
- *	sht.c - Testprogram for shared memory refclock
- *
- * This file is Copyright (c) 2010 by the GPSD project BSD terms apply:
- * see the file COPYING in the distribution root for details.
- */
-
-#include <string.h>
-#include <libgen.h>
-#include <stdbool.h>
-#include <math.h>
-#include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#ifndef S_SPLINT_S
-#include <sys/wait.h>
-#include <sys/socket.h>
-#include <unistd.h>
-#endif /* S_SPLINT_S */
-
-#include "gpsd.h"
-
-#ifdef NTPSHM_ENABLE
-#include <sys/time.h>
-#include <sys/ipc.h>
-#include <sys/shm.h>
-
-#define NTPD_BASE	0x4e545030	/* "NTP0" */
-#define SHM_UNIT	0	/* SHM driver unit number (0..3) */
-
-#define PPS_MIN_FIXES	3	/* # fixes to wait for before shipping PPS */
-
-struct shmTime
-{
-    int mode;			/* 0 - if valid set
-				 *       use values,
-				 *       clear valid
-				 * 1 - if valid set
-				 *       if count before and after read of values is equal,
-				 *         use values
-				 *       clear valid
-				 */
-    int count;
-    time_t clockTimeStampSec;
-    int clockTimeStampUSec;
-    time_t receiveTimeStampSec;
-    int receiveTimeStampUSec;
-    int leap;
-    int precision;
-    int nsamples;
-    int valid;
-    int pad[10];
-};
-
-/* Note: you can start gpsd as non-root, and have it work with ntpd.
- * However, it will then only use the ntpshm segments 2 and 3.
- *
- * Ntpd always runs as root (to be able to control the system clock).
- * Its logics for the creation of ntpshm segments are:
- *
- * Segments 0 and 1: permissions 0600, i.e. other programs can only
- *                   read and write as root.
- *
- * Segments 2 and 3: permissions 0666, i.e. other programs can read
- *                   and write as any user.  I.e.: if ntpd has been
- *                   configured to use these segments, any
- *                   unpriviliged user is allowed to provide data
- *                   for synchronisation.
- * * As gpsd can be started as both root and non-root, this behaviour is
- * mimicked by:
- *
- * Started as root: do as ntpd when attaching (creating) the segments.
- * (In contrast to ntpd, which only attaches (creates) configured
- * segments, gpsd creates all segments.)
- *
- * Started as non-root: only attach (create) segments 2 and 3 with
- * permissions 0666.  As the permissions are for any user, the creator
- * does not matter.
- *
- * For each GPS module gpsd controls, it will use the attached ntpshm
- * segments in pairs (for coarse clock and pps source, respectively)
- * starting from the first found segments.  I.e. started as root, one
- * GPS will deliver data on segments 0 and 1, and as non-root data
- * will be delivered on segments 2 and 3.
- *
- * to debug, try looking at the live segments this way
- *
- *  ipcs -m
- * 
- * results  should look like this:
- * ------ Shared Memory Segments --------
- *  key        shmid      owner      perms      bytes      nattch     status
- *  0x4e545030 0          root       700        96         2
- *  0x4e545031 32769      root       700        96         2
- *  0x4e545032 163842     root       666        96         1
- *  0x4e545033 196611     root       666        96         1
- *
- * For a bit more data try this:
- *  cat /proc/sysvipc/shm
- *
- * If gpsd can not open the segments be sure you are not running SELinux
- * or apparmor.
- *
- * if you see the shared segments (keys 1314148400 -- 1314148403), and
- * no gpsd or ntpd is running then try removing them like this:
- *
- * ipcrm  -M 0x4e545030
- * ipcrm  -M 0x4e545031
- * ipcrm  -M 0x4e545032
- * ipcrm  -M 0x4e545033
- */
-static /*@null@*/ volatile struct shmTime *getShmTime(struct gps_context_t *context, int unit)
-{
-    int shmid;
-    unsigned int perms;
-    volatile struct shmTime *p;
-    // set the SHM perms the way ntpd does
-    if (unit < 2) {
-	// we are root, be careful
-	perms = 0600;
-    } else {
-	// we are not root, try to work anyway
-	perms = 0666;
-    }
-
-    /*
-     * Note: this call requires root under BSD, and possibly on
-     * well-secured Linux systems.  This is why ntpshm_init() has to be
-     * called before privilege-dropping.
-     */
-    shmid = shmget((key_t) (NTPD_BASE + unit),
-		   sizeof(struct shmTime), (int)(IPC_CREAT | perms));
-    if (shmid == -1) {
-	gpsd_report(context->debug, LOG_ERROR,
-		    "NTPD shmget(%ld, %zd, %o) fail: %s\n",
-		    (long int)(NTPD_BASE + unit), sizeof(struct shmTime),
-		    (int)perms, strerror(errno));
-	return NULL;
-    }
-    p = (struct shmTime *)shmat(shmid, 0, 0);
-    /*@ -mustfreefresh */
-    if ((int)(long)p == -1) {
-	gpsd_report(context->debug, LOG_ERROR,
-		    "NTPD shmat failed: %s\n",
-		    strerror(errno));
-	return NULL;
-    }
-    gpsd_report(context->debug, LOG_PROG,
-		"NTPD shmat(%d,0,0) succeeded, segment %d\n",
-		shmid, unit);
-    return p;
-    /*@ +mustfreefresh */
-}
-
-void ntpshm_init(struct gps_context_t *context)
-/* Attach all NTP SHM segments. Called once at startup, while still root. */
-{
-    int i;
-
-    for (i = 0; i < NTPSHMSEGS; i++) {
-	// Only grab the first two when running as root.
-	if (2 <= i || 0 == getuid()) {
-	    context->shmTime[i] = getShmTime(context, i);
-	}
-    }
-    memset(context->shmTimeInuse, 0, sizeof(context->shmTimeInuse));
-    context->enable_ntpshm = true;
-}
-
-static int ntpshm_alloc(struct gps_context_t *context)
-/* allocate NTP SHM segment.  return its segment number, or -1 */
-{
-    int i;
-
-    for (i = 0; i < NTPSHMSEGS; i++)
-	if (context->shmTime[i] != NULL && !context->shmTimeInuse[i]) {
-	    context->shmTimeInuse[i] = true;
-
-	    /*
-	     * In case this segment gets sent to ntpd before an
-	     * ephemeris is available, the LEAP_NOTINSYNC value will
-	     * tell ntpd that this source is in a "clock alarm" state
-	     * and should be ignored.  The goal is to prevent ntpd
-	     * from declaring the GPS a falseticker before it gets
-	     * all its marbles together.
-	     */
-	    memset((void *)context->shmTime[i], 0, sizeof(struct shmTime));
-	    context->shmTime[i]->mode = 1;
-	    context->shmTime[i]->leap = LEAP_NOTINSYNC;
-	    context->shmTime[i]->precision = -1;	/* initially 0.5 sec */
-	    context->shmTime[i]->nsamples = 3;	/* stages of median filter */
-
-	    return i;
-	}
-
-    return -1;
-}
-
-static bool ntpshm_free(struct gps_context_t * context, int segment)
-/* free NTP SHM segment */
-{
-    if (segment < 0 || segment >= NTPSHMSEGS)
-	return false;
-
-    context->shmTimeInuse[segment] = false;
-    return true;
-}
-
-int ntpshm_put(struct gps_device_t *session, double fixtime, double fudge)
-/* put a received fix time into shared memory for NTP */
-{
-    /* shmTime is volatile to try to prevent C compiler from reordering
-     * writes, or optimizing some 'dead code'.  but CPU cache may still
-     *write out of order since we do not use memory barriers, yet */
-    volatile struct shmTime *shmTime = NULL;
-    struct timeval tv;
-    double seconds, microseconds;
-
-    // gpsd_report(session->context->debug, LOG_PROG, "NTP: doing ntpshm_put(,%g, %g)\n", fixtime, fudge);
-    if (session->shmindex < 0 ||
-	(shmTime = session->context->shmTime[session->shmindex]) == NULL) {
-	gpsd_report(session->context->debug, LOG_RAW,
-		    "NTPD missing shm\n");
-	return 0;
-    }
-
-    (void)gettimeofday(&tv, NULL);
-    fixtime += fudge;
-    microseconds = 1000000.0 * modf(fixtime, &seconds);
-    if (shmTime->clockTimeStampSec == (time_t) seconds) {
-	gpsd_report(session->context->debug, LOG_RAW,
-		    "NTPD ntpshm_put: skipping duplicate second\n");
-	return 0;
-    }
-
-    /* we use the shmTime mode 1 protocol
-     *
-     * ntpd does this:
-     *
-     * reads valid.
-     * IFF valid is 1
-     *    reads count
-     *    reads values
-     *    reads count
-     *    IFF count unchanged
-     *        use values
-     *    clear valid
-     *
-     */
-    shmTime->valid = 0;
-    shmTime->count++;
-    /* FIXME need a memory barrier here to prevent write reordering by
-     * the compiler or CPU cache */
-    shmTime->clockTimeStampSec = (time_t) seconds;
-    shmTime->clockTimeStampUSec = (int)microseconds;
-    shmTime->receiveTimeStampSec = (time_t) tv.tv_sec;
-    shmTime->receiveTimeStampUSec = (int)tv.tv_usec;
-    shmTime->leap = session->context->leap_notify;
-    /* setting the precision here does not seem to help anything, too
-     * hard to calculate properly anyway.  Let ntpd figure it out.
-     * Any NMEA will be about -1 or -2.
-     * Garmin GPS-18/USB is around -6 or -7.
-     */
-    /* FIXME need a memory barrier here to prevent write reordering by
-     * the compiler or CPU cache */
-    shmTime->count++;
-    shmTime->valid = 1;
-
-    gpsd_report(session->context->debug, LOG_RAW,
-		"NTPD ntpshm_put: Clock: %lu.%06lu @ %lu.%06lu, fudge: %0.3f\n",
-		(unsigned long)seconds, (unsigned long)microseconds,
-		(unsigned long)tv.tv_sec, (unsigned long)tv.tv_usec, fudge);
-
-    return 1;
-}
-
-#ifdef PPS_ENABLE
-/*@unused@*//* splint is confused here */
-/* put NTP shared memory info based on received PPS pulse
- *
- * good news is that kernel PPS gives us nSec resolution
- * bad news is that ntpshm only has uSec resolution
- *
- * actual_tv is the actual time we think the PPS happened
- * ts is the time we saw the pulse
- */
-static int ntpshm_pps(struct gps_device_t *session, struct timeval *actual_tv,
-	struct timespec *ts)
-{
-    volatile struct shmTime *shmTime = NULL, *shmTimeP = NULL;
-    struct timeval tv;
-    int precision;
-    double offset;
-
-    if (0 > session->shmindex || 0 > session->shmTimeP ||
-	(shmTime = session->context->shmTime[session->shmindex]) == NULL ||
-	(shmTimeP = session->context->shmTime[session->shmTimeP]) == NULL)
-	return 0;
-
-    /* for now we use uSec, not nSec */
-    /*@-type@*//* splint is confused about struct timespec */
-    TSTOTV( &tv, ts );
-    /*@+type@*/
-
-    /* we use the shmTime mode 1 protocol
-     *
-     * ntpd does this:
-     *
-     * reads valid.
-     * IFF valid is 1
-     *    reads count
-     *    reads values
-     *    reads count
-     *    IFF count unchanged
-     *        use values
-     *    clear valid
-     *
-     */
-    shmTimeP->valid = 0;
-    shmTimeP->count++;
-    shmTimeP->clockTimeStampSec = (time_t)actual_tv->tv_sec;
-    shmTimeP->clockTimeStampUSec = (int)actual_tv->tv_usec;
-    shmTimeP->receiveTimeStampSec = (time_t)tv.tv_sec;
-    shmTimeP->receiveTimeStampUSec = (int)tv.tv_usec;
-    shmTimeP->leap = session->context->leap_notify;
-    /* precision is a placebo, ntpd does not really use it
-     * real world accuracy is around 16uS, thus -16 precision */
-    shmTimeP->precision = -16;
-    shmTimeP->count++;
-    shmTimeP->valid = 1;
-
-    /* this is more an offset jitter/dispersion than precision,
-     * but still useful for debug */
-    offset = fabs((double)(tv.tv_sec - actual_tv->tv_sec)
-		  + ((double)(tv.tv_usec - actual_tv->tv_usec) / 1000000.0));
-    precision = offset != 0 ? (int)(ceil(log(offset) / M_LN2)) : -20;
-    /*@-type@*//* splint is confused about struct timespec */
-    gpsd_report(session->context->debug, LOG_RAW,
-		"PPS ntpshm_pps %lu.%03lu @ %lu.%09lu, preci %d\n",
-		(unsigned long)actual_tv->tv_sec, 
-		(unsigned long)actual_tv->tv_usec,
-		(unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec,
-		precision);
-    /*@+type@*/
-    return 1;
-}
-
-#define SOCK_MAGIC 0x534f434b
-struct sock_sample {
-    struct timeval tv;
-    double offset;
-    int pulse;
-    int leap;
-    /* cppcheck-suppress unusedStructMember */
-    int _pad;
-    int magic;      /* must be SOCK_MAGIC */
-};
-
-/*@-mustfreefresh@*/
-static void init_hook(struct gps_device_t *session)
-/* for chrony SOCK interface, which allows nSec timekeeping */
-{
-    /* open the chrony socket */
-    char chrony_path[PATH_MAX];
-
-    session->chronyfd = -1;
-    if ( 0 == getuid() ) {
-	/* this case will fire on command-line devices;
-	 * they're opened before priv-dropping.  Matters because
-         * only root can use /var/run.
-	 */
-	(void)snprintf(chrony_path, sizeof (chrony_path),
-		"/var/run/chrony.%s.sock", basename(session->gpsdata.dev.path));
-    } else {
-	(void)snprintf(chrony_path, sizeof (chrony_path),
-		"/tmp/chrony.%s.sock", 	basename(session->gpsdata.dev.path));
-    }
-
-    if (access(chrony_path, F_OK) != 0) {
-	gpsd_report(session->context->debug, LOG_PROG,
-		    "PPS chrony socket %s doesn't exist\n", chrony_path);
-    } else {
-	session->chronyfd = netlib_localsocket(chrony_path, SOCK_DGRAM);
-	if (session->chronyfd < 0)
-	    gpsd_report(session->context->debug, LOG_PROG,
-		"PPS connect chrony socket failed: %s, error: %d, errno: %d/%s\n",
-		chrony_path, session->chronyfd, errno, strerror(errno));
-	else
-	    gpsd_report(session->context->debug, LOG_RAW,
-			"PPS using chrony socket: %s\n", chrony_path);
-    }
-}
-/*@+mustfreefresh@*/
-
-
-/* actual_tv is when we think the PPS pulse wass */
-/* ts is the local clocke time we saw the pulse */
-/* offset is actual_tv - tv */
-static void chrony_send(struct gps_device_t *session,
-			struct timeval *actual_tv,
-			struct timespec *ts UNUSED,  double offset)
-{
-    struct sock_sample sample;
-
-    /* FIXME!! offset is double of the error from local time */
-    /* chrony expects tv-sec since Jan 1970 */
-    sample.pulse = 0;
-    sample.leap = session->context->leap_notify;
-    sample.magic = SOCK_MAGIC;
-    sample.tv = *actual_tv; /* structure copy */
-    sample.offset = offset; 
-
-    (void)send(session->chronyfd, &sample, sizeof (sample), 0);
-}
-
-static void wrap_hook(struct gps_device_t *session)
-{
-    if (session->chronyfd != -1)
-	(void)close(session->chronyfd);
-}
-
-static /*@observer@*/ char *report_hook(struct gps_device_t *session,
-			struct timeval *actual_tv, 
-			struct timespec *ts, 
-			double edge_offset)
-/* ship the time of a PPS event to ntpd and/or chrony */
-{
-    char *log1;
-
-    if (!session->ship_to_ntpd)
-	return "skipped ship_to_ntp=0";
-
-    /*
-     * Only listen to PPS after several consecutive fixes,
-     * otherwise time may be inaccurate.  (We know this is
-     * required on some Garmins in binary mode; safest to do it
-     * for all case we're talking to a Garmin in text mode, and
-     * out of general safety-first conservatism.)
-     *
-     * Not sure yet how to handle uBlox UBX_MODE_TMONLY
-     */
-    if (session->fixcnt <= PPS_MIN_FIXES)
-	return "no fix";
-
-    log1 = "accepted";
-    if ( 0 <= session->chronyfd ) {
-	log1 = "accepted chrony sock";
-	chrony_send(session, actual_tv, ts, edge_offset);
-    }
-    (void)ntpshm_pps(session, actual_tv, ts);
-
-    return log1;
-}
-
-static void error_hook(struct gps_device_t *session)
-{
-    (void)ntpshm_free(session->context, session->shmTimeP);
-}
-#endif	/* PPS_ENABLE */
-
-void ntpd_link_deactivate(struct gps_device_t *session)
-/* release ntpshm storage for a session */
-{
-    (void)ntpshm_free(session->context, session->shmindex);
-#if defined(PPS_ENABLE)
-    if (session->shmTimeP != -1) {
-	pps_thread_deactivate(session);
-	(void)ntpshm_free(session->context, session->shmTimeP);
-    }
-#endif	/* PPS_ENABLE */
-}
-
-void ntpd_link_activate(struct gps_device_t *session)
-/* set up ntpshm storage for a session */
-{
-    /* If we are talking to ntpd, allocate a shared-memory segment for "NMEA" time data */
-    if (session->context->enable_ntpshm)
-	session->shmindex = ntpshm_alloc(session->context);
-
-    if (0 > session->shmindex) {
-	gpsd_report(session->context->debug, LOG_INF, "NTPD ntpshm_alloc() failed\n");
-#if defined(PPS_ENABLE)
-    } else {
-	/* We also have the 1pps capability, allocate a shared-memory segment
-	 * for the 1pps time data and launch a thread to capture the 1pps
-	 * transitions
-	 */
-	if ((session->shmTimeP = ntpshm_alloc(session->context)) < 0) {
-	    gpsd_report(session->context->debug, LOG_INF, "NTPD ntpshm_alloc(1) failed\n");
-	} else {
-	    session->thread_init_hook = init_hook;
-	    session->thread_error_hook = error_hook;
-	    session->thread_report_hook = report_hook;
-	    session->thread_wrap_hook = wrap_hook;
-	    pps_thread_activate(session);
-	}
-#endif /* PPS_ENABLE */
-    }
-}
-
-#endif /* NTPSHM_ENABLE */
-/* end */