refclock_shm.c revision 1.1.1.1.6.1
1 /* $NetBSD: refclock_shm.c,v 1.1.1.1.6.1 2012/04/17 00:03:48 yamt Exp $ */ 2 3 /* 4 * refclock_shm - clock driver for utc via shared memory 5 * - under construction - 6 * To add new modes: Extend or union the shmTime-struct. Do not 7 * extend/shrink size, because otherwise existing implementations 8 * will specify wrong size of shared memory-segment 9 * PB 18.3.97 10 */ 11 12 #ifdef HAVE_CONFIG_H 13 # include <config.h> 14 #endif 15 16 #if defined(REFCLOCK) && defined(CLOCK_SHM) 17 18 #include "ntpd.h" 19 #undef fileno 20 #include "ntp_io.h" 21 #undef fileno 22 #include "ntp_refclock.h" 23 #undef fileno 24 #include "ntp_unixtime.h" 25 #undef fileno 26 #include "ntp_stdlib.h" 27 28 #undef fileno 29 #include <ctype.h> 30 #undef fileno 31 32 #ifndef SYS_WINNT 33 # include <sys/ipc.h> 34 # include <sys/shm.h> 35 # include <assert.h> 36 # include <unistd.h> 37 # include <stdio.h> 38 #endif 39 40 /* 41 * This driver supports a reference clock attached thru shared memory 42 */ 43 44 /* Temp hack to simplify testing of the old mode. */ 45 #define OLDWAY 0 46 47 /* 48 * SHM interface definitions 49 */ 50 #define PRECISION (-1) /* precision assumed (0.5 s) */ 51 #define REFID "SHM" /* reference ID */ 52 #define DESCRIPTION "SHM/Shared memory interface" 53 54 #define NSAMPLES 3 /* stages of median filter */ 55 56 /* 57 * Function prototypes 58 */ 59 static int shm_start (int unit, struct peer *peer); 60 static void shm_shutdown (int unit, struct peer *peer); 61 static void shm_poll (int unit, struct peer *peer); 62 static void shm_timer (int unit, struct peer *peer); 63 int shm_peek (int unit, struct peer *peer); 64 void shm_clockstats (int unit, struct peer *peer); 65 66 /* 67 * Transfer vector 68 */ 69 struct refclock refclock_shm = { 70 shm_start, /* start up driver */ 71 shm_shutdown, /* shut down driver */ 72 shm_poll, /* transmit poll message */ 73 noentry, /* not used: control */ 74 noentry, /* not used: init */ 75 noentry, /* not used: buginfo */ 76 shm_timer, /* once per second */ 77 }; 78 79 struct shmTime { 80 int mode; /* 0 - if valid set 81 * use values, 82 * clear valid 83 * 1 - if valid set 84 * if count before and after read of values is equal, 85 * use values 86 * clear valid 87 */ 88 int count; 89 time_t clockTimeStampSec; 90 int clockTimeStampUSec; 91 time_t receiveTimeStampSec; 92 int receiveTimeStampUSec; 93 int leap; 94 int precision; 95 int nsamples; 96 int valid; 97 int dummy[10]; 98 }; 99 100 struct shmunit { 101 struct shmTime *shm; /* pointer to shared memory segment */ 102 103 /* debugging/monitoring counters - reset when printed */ 104 int ticks; /* number of attempts to read data*/ 105 int good; /* number of valid samples */ 106 int notready; /* number of peeks without data ready */ 107 int bad; /* number of invalid samples */ 108 int clash; /* number of access clashes while reading */ 109 }; 110 111 112 struct shmTime *getShmTime(int); 113 114 struct shmTime *getShmTime (int unit) { 115 #ifndef SYS_WINNT 116 int shmid=0; 117 118 /* 0x4e545030 is NTP0. 119 * Big units will give non-ascii but that's OK 120 * as long as everybody does it the same way. 121 */ 122 shmid=shmget (0x4e545030+unit, sizeof (struct shmTime), 123 IPC_CREAT|(unit<2?0600:0666)); 124 if (shmid==-1) { /*error */ 125 msyslog(LOG_ERR,"SHM shmget (unit %d): %s",unit,strerror(errno)); 126 return 0; 127 } 128 else { /* no error */ 129 struct shmTime *p=(struct shmTime *)shmat (shmid, 0, 0); 130 if ((int)(long)p==-1) { /* error */ 131 msyslog(LOG_ERR,"SHM shmat (unit %d): %s",unit,strerror(errno)); 132 return 0; 133 } 134 return p; 135 } 136 #else 137 char buf[10]; 138 LPSECURITY_ATTRIBUTES psec=0; 139 HANDLE shmid=0; 140 SECURITY_DESCRIPTOR sd; 141 SECURITY_ATTRIBUTES sa; 142 snprintf(buf, sizeof(buf), "NTP%d", unit); 143 if (unit >= 2) { /* world access */ 144 if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION)) { 145 msyslog(LOG_ERR,"SHM InitializeSecurityDescriptor (unit %d): %m",unit); 146 return 0; 147 } 148 if (!SetSecurityDescriptorDacl(&sd,1,0,0)) { 149 msyslog(LOG_ERR,"SHM SetSecurityDescriptorDacl (unit %d): %m",unit); 150 return 0; 151 } 152 sa.nLength=sizeof (SECURITY_ATTRIBUTES); 153 sa.lpSecurityDescriptor=&sd; 154 sa.bInheritHandle=0; 155 psec=&sa; 156 } 157 shmid=CreateFileMapping ((HANDLE)0xffffffff, psec, PAGE_READWRITE, 158 0, sizeof (struct shmTime),buf); 159 if (!shmid) { /*error*/ 160 char buf[1000]; 161 FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM, 162 0, GetLastError (), 0, buf, sizeof (buf), 0); 163 msyslog(LOG_ERR,"SHM CreateFileMapping (unit %d): %s",unit,buf); 164 return 0; 165 } 166 else { 167 struct shmTime *p=(struct shmTime *) MapViewOfFile (shmid, 168 FILE_MAP_WRITE, 0, 0, sizeof (struct shmTime)); 169 if (p==0) { /*error*/ 170 char buf[1000]; 171 FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM, 172 0, GetLastError (), 0, buf, sizeof (buf), 0); 173 msyslog(LOG_ERR,"SHM MapViewOfFile (unit %d): %s",unit,buf); 174 return 0; 175 } 176 return p; 177 } 178 #endif 179 } 180 /* 181 * shm_start - attach to shared memory 182 */ 183 static int 184 shm_start( 185 int unit, 186 struct peer *peer 187 ) 188 { 189 struct refclockproc *pp; 190 struct shmunit *up; 191 192 pp = peer->procptr; 193 pp->io.clock_recv = noentry; 194 pp->io.srcclock = (caddr_t)peer; 195 pp->io.datalen = 0; 196 pp->io.fd = -1; 197 198 up = emalloc(sizeof(*up)); 199 memset(up, 0, sizeof(*up)); 200 pp->unitptr = (caddr_t)up; 201 202 up->shm = getShmTime(unit); 203 204 /* 205 * Initialize miscellaneous peer variables 206 */ 207 memcpy((char *)&pp->refid, REFID, 4); 208 if (up->shm != 0) { 209 up->shm->precision = PRECISION; 210 peer->precision = up->shm->precision; 211 up->shm->valid=0; 212 up->shm->nsamples=NSAMPLES; 213 pp->clockdesc = DESCRIPTION; 214 return (1); 215 } 216 else { 217 return 0; 218 } 219 } 220 221 222 /* 223 * shm_shutdown - shut down the clock 224 */ 225 static void 226 shm_shutdown( 227 int unit, 228 struct peer *peer 229 ) 230 { 231 struct refclockproc *pp; 232 struct shmunit *up; 233 234 pp = peer->procptr; 235 up = (struct shmunit *)pp->unitptr; 236 237 if (NULL == up) 238 return; 239 #ifndef SYS_WINNT 240 /* HMS: shmdt()wants char* or const void * */ 241 (void) shmdt ((char *)up->shm); 242 #else 243 UnmapViewOfFile (up->shm); 244 #endif 245 free(up); 246 } 247 248 249 /* 250 * shm_timer - called every second 251 */ 252 static void 253 shm_timer(int unit, struct peer *peer) 254 { 255 if (OLDWAY) 256 return; 257 258 shm_peek(unit, peer); 259 } 260 261 262 /* 263 * shm_poll - called by the transmit procedure 264 */ 265 static void 266 shm_poll( 267 int unit, 268 struct peer *peer 269 ) 270 { 271 struct refclockproc *pp; 272 int ok; 273 274 pp = peer->procptr; 275 276 if (OLDWAY) { 277 ok = shm_peek(unit, peer); 278 if (!ok) return; 279 } 280 281 /* 282 * Process median filter samples. If none received, declare a 283 * timeout and keep going. 284 */ 285 if (pp->coderecv == pp->codeproc) { 286 refclock_report(peer, CEVNT_TIMEOUT); 287 shm_clockstats(unit, peer); 288 return; 289 } 290 pp->lastref = pp->lastrec; 291 refclock_receive(peer); 292 shm_clockstats(unit, peer); 293 } 294 295 /* 296 * shm_peek - try to grab a sample 297 */ 298 int shm_peek( 299 int unit, 300 struct peer *peer 301 ) 302 { 303 struct refclockproc *pp; 304 struct shmunit *up; 305 struct shmTime *shm; 306 307 /* 308 * This is the main routine. It snatches the time from the shm 309 * board and tacks on a local timestamp. 310 */ 311 pp = peer->procptr; 312 up = (struct shmunit*)pp->unitptr; 313 up->ticks++; 314 if (up->shm == 0) { 315 /* try to map again - this may succeed if meanwhile some- 316 body has ipcrm'ed the old (unaccessible) shared mem segment */ 317 up->shm = getShmTime(unit); 318 } 319 shm = up->shm; 320 if (shm == 0) { 321 refclock_report(peer, CEVNT_FAULT); 322 return(0); 323 } 324 if (shm->valid) { 325 struct timeval tvr; 326 struct timeval tvt; 327 struct tm *t; 328 int ok=1; 329 tvr.tv_sec = 0; 330 tvr.tv_usec = 0; 331 tvt.tv_sec = 0; 332 tvt.tv_usec = 0; 333 switch (shm->mode) { 334 case 0: { 335 tvr.tv_sec=shm->receiveTimeStampSec; 336 tvr.tv_usec=shm->receiveTimeStampUSec; 337 tvt.tv_sec=shm->clockTimeStampSec; 338 tvt.tv_usec=shm->clockTimeStampUSec; 339 } 340 break; 341 case 1: { 342 int cnt=shm->count; 343 tvr.tv_sec=shm->receiveTimeStampSec; 344 tvr.tv_usec=shm->receiveTimeStampUSec; 345 tvt.tv_sec=shm->clockTimeStampSec; 346 tvt.tv_usec=shm->clockTimeStampUSec; 347 ok=(cnt==shm->count); 348 } 349 break; 350 default: 351 msyslog (LOG_ERR, "SHM: bad mode found in shared memory: %d",shm->mode); 352 } 353 shm->valid=0; 354 if (ok) { 355 time_t help; /* XXX NetBSD has incompatible tv_sec */ 356 357 TVTOTS(&tvr,&pp->lastrec); 358 pp->lastrec.l_ui += JAN_1970; 359 /* pp->lasttime = current_time; */ 360 pp->polls++; 361 help = tvt.tv_sec; 362 t = gmtime (&help); 363 pp->day=t->tm_yday+1; 364 pp->hour=t->tm_hour; 365 pp->minute=t->tm_min; 366 pp->second=t->tm_sec; 367 pp->nsec=tvt.tv_usec * 1000; 368 peer->precision=shm->precision; 369 pp->leap=shm->leap; 370 } 371 else { 372 refclock_report(peer, CEVNT_FAULT); 373 msyslog (LOG_NOTICE, "SHM: access clash in shared memory"); 374 up->clash++; 375 return(0); 376 } 377 } 378 else { 379 refclock_report(peer, CEVNT_TIMEOUT); 380 up->notready++; 381 return(0); 382 } 383 if (!refclock_process(pp)) { 384 refclock_report(peer, CEVNT_BADTIME); 385 up->bad++; 386 return(0); 387 } 388 up->good++; 389 return(1); 390 } 391 392 /* 393 * shm_clockstats - dump and reset counters 394 */ 395 void shm_clockstats( 396 int unit, 397 struct peer *peer 398 ) 399 { 400 struct refclockproc *pp; 401 struct shmunit *up; 402 char logbuf[256]; 403 404 pp = peer->procptr; 405 up = (struct shmunit*)pp->unitptr; 406 407 if (!(pp->sloppyclockflag & CLK_FLAG4)) return; 408 409 snprintf(logbuf, sizeof(logbuf), "%3d %3d %3d %3d %3d", 410 up->ticks, up->good, up->notready, up->bad, up->clash); 411 record_clock_stats(&peer->srcadr, logbuf); 412 413 up->ticks = up->good = up->notready =up->bad = up->clash = 0; 414 415 } 416 417 #else 418 int refclock_shm_bs; 419 #endif /* REFCLOCK */ 420
Indexes created Wed Jul 15 00:26:21 UTC 2026