PostgreSQL Source Code: src/backend/port/posix_sema.c File Reference (original) (raw)

#include "[postgres.h](postgres%5F8h%5Fsource.html)"
#include <fcntl.h>
#include <semaphore.h>
#include <signal.h>
#include <[unistd.h](unistd%5F8h%5Fsource.html)>
#include <sys/stat.h>
#include "[miscadmin.h](miscadmin%5F8h%5Fsource.html)"
#include "[storage/ipc.h](ipc%5F8h%5Fsource.html)"
#include "[storage/pg_sema.h](pg%5F%5Fsema%5F8h%5Fsource.html)"
#include "[storage/shmem.h](shmem%5F8h%5Fsource.html)"

Go to the source code of this file.

◆ IPCProtection

#define IPCProtection (0600) /* access/modify by user only */

◆ PG_SEM_REF

| #define PG_SEM_REF | ( | | x | ) | (&(x)->sem_padded.pgsem) | | -------------------- | - | | ---------------------------------------------------- | - | ---------------------------------------------------------------------------- |

◆ PGSemaphoreData

◆ SemTPadded

◆ PGReserveSemaphores()

Definition at line 196 of file posix_sema.c.

197{

198 struct stat statbuf;

199

200

201

202

203

204

205

209 errmsg("could not stat data directory \"%s\": %m",

211

212#ifdef USE_NAMED_POSIX_SEMAPHORES

213 mySemPointers = (sem_t **) malloc(maxSemas * sizeof(sem_t *));

214 if (mySemPointers == NULL)

216#else

217

218

219

220

221

224#endif

225

229

231}

int errcode_for_file_access(void)

int errmsg(const char *fmt,...)

#define ereport(elevel,...)

void on_shmem_exit(pg_on_exit_callback function, Datum arg)

struct PGSemaphoreData * PGSemaphore

Size PGSemaphoreShmemSize(int maxSemas)

static PGSemaphore sharedSemas

static void ReleaseSemaphores(int status, Datum arg)

void * ShmemAllocUnlocked(Size size)

References DataDir, elog, ereport, errcode_for_file_access(), errmsg(), FATAL, malloc, maxSems, nextSemKey, numSems, on_shmem_exit(), PANIC, PGSemaphoreShmemSize(), ReleaseSemaphores(), sharedSemas, ShmemAllocUnlocked(), stat::st_ino, and stat.

Referenced by CreateSharedMemoryAndSemaphores().

◆ PGSemaphoreCreate()

Definition at line 261 of file posix_sema.c.

262{

264 sem_t *newsem;

265

266

268

270 elog(PANIC, "too many semaphores created");

271

272#ifdef USE_NAMED_POSIX_SEMAPHORES

274

275 mySemPointers[numSems] = newsem;

277#else

281#endif

282

284

285 return sema;

286}

Assert(PointerIsAligned(start, uint64))

static void PosixSemaphoreCreate(sem_t *sem)

References Assert(), elog, IsUnderPostmaster, maxSems, numSems, PANIC, PG_SEM_REF, PosixSemaphoreCreate(), and sharedSemas.

Referenced by InitProcGlobal().

◆ PGSemaphoreLock()

◆ PGSemaphoreReset()

◆ PGSemaphoreShmemSize()

◆ PGSemaphoreTryLock()

Definition at line 364 of file posix_sema.c.

365{

366 int errStatus;

367

368

369

370

371

372

373 do

374 {

375 errStatus = sem_trywait(PG_SEM_REF(sema));

376 } while (errStatus < 0 && errno == EINTR);

377

378 if (errStatus < 0)

379 {

380 if (errno == EAGAIN || errno == EDEADLK)

381 return false;

382

383 elog(FATAL, "sem_trywait failed: %m");

384 }

385

386 return true;

387}

References EAGAIN, EINTR, elog, FATAL, and PG_SEM_REF.

◆ PGSemaphoreUnlock()

Definition at line 339 of file posix_sema.c.

340{

341 int errStatus;

342

343

344

345

346

347

348

349 do

350 {

351 errStatus = sem_post(PG_SEM_REF(sema));

352 } while (errStatus < 0 && errno == EINTR);

353

354 if (errStatus < 0)

355 elog(FATAL, "sem_post failed: %m");

356}

References EINTR, elog, FATAL, and PG_SEM_REF.

Referenced by LWLockAcquire(), LWLockAcquireOrWait(), LWLockDequeueSelf(), LWLockUpdateVar(), LWLockWaitForVar(), LWLockWakeup(), ProcArrayGroupClearXid(), and TransactionGroupUpdateXidStatus().

◆ PosixSemaphoreCreate()

◆ PosixSemaphoreKill()

Definition at line 147 of file posix_sema.c.

148{

149#ifdef USE_NAMED_POSIX_SEMAPHORES

150

151 if (sem_close(sem) < 0)

152 elog(LOG, "sem_close failed: %m");

153#else

154

155 if (sem_destroy(sem) < 0)

156 elog(LOG, "sem_destroy failed: %m");

157#endif

158}

References elog, LOG, and sem.

Referenced by ReleaseSemaphores().

◆ ReleaseSemaphores()

◆ maxSems

◆ nextSemKey

◆ numSems

◆ sharedSemas