diff options
Diffstat (limited to 'src/mutex/mut_fcntl.c')
| -rw-r--r-- | src/mutex/mut_fcntl.c | 248 |
1 files changed, 0 insertions, 248 deletions
diff --git a/src/mutex/mut_fcntl.c b/src/mutex/mut_fcntl.c deleted file mode 100644 index 0694aa59..00000000 --- a/src/mutex/mut_fcntl.c +++ /dev/null @@ -1,248 +0,0 @@ -/*- - * See the file LICENSE for redistribution information. - * - * Copyright (c) 1996, 2012 Oracle and/or its affiliates. All rights reserved. - * - * $Id$ - */ - -#include "db_config.h" - -#include "db_int.h" - -static inline int __db_fcntl_mutex_lock_int - __P((ENV *, db_mutex_t, db_timeout_t, int)); - -/* - * __db_fcntl_mutex_init -- - * Initialize a fcntl mutex. - * - * PUBLIC: int __db_fcntl_mutex_init __P((ENV *, db_mutex_t, u_int32_t)); - */ -int -__db_fcntl_mutex_init(env, mutex, flags) - ENV *env; - db_mutex_t mutex; - u_int32_t flags; -{ - COMPQUIET(env, NULL); - COMPQUIET(mutex, MUTEX_INVALID); - COMPQUIET(flags, 0); - - return (0); -} - -/* - * __db_fcntl_mutex_lock_int - * Internal function to lock a mutex, blocking only when requested - */ -inline int -__db_fcntl_mutex_lock_int(env, mutex, timeout, wait) - ENV *env; - db_mutex_t mutex; - db_timeout_t timeout; - int wait; -{ - DB_ENV *dbenv; - DB_MUTEX *mutexp; - DB_THREAD_INFO *ip; - struct flock k_lock; - int locked, ms, ret; - db_timespec now, timespec; - db_timeout_t time_left; - - dbenv = env->dbenv; - - if (!MUTEX_ON(env) || F_ISSET(dbenv, DB_ENV_NOLOCKING)) - return (0); - - mutexp = MUTEXP_SET(env, mutex); - - CHECK_MTX_THREAD(env, mutexp); - -#ifdef HAVE_STATISTICS - if (F_ISSET(mutexp, DB_MUTEX_LOCKED)) - ++mutexp->mutex_set_wait; - else - ++mutexp->mutex_set_nowait; -#endif - - /* Initialize the lock. */ - k_lock.l_whence = SEEK_SET; - k_lock.l_start = mutex; - k_lock.l_len = 1; - - if (timeout != 0) { - timespecclear(×pec); - __clock_set_expires(env, ×pec, timeout); - } - - /* - * Only check the thread state once, by initializing the thread - * control block pointer to null. If it is not the failchk - * thread, then ip will have a valid value subsequent times - * in the loop. - */ - ip = NULL; - - for (locked = 0;;) { - /* - * Wait for the lock to become available; wait 1ms initially, - * up to 1 second. - */ - for (ms = 1; F_ISSET(mutexp, DB_MUTEX_LOCKED);) { - if (F_ISSET(dbenv, DB_ENV_FAILCHK) && - ip == NULL && dbenv->is_alive(dbenv, - mutexp->pid, mutexp->tid, 0) == 0) { - ret = __env_set_state(env, &ip, THREAD_VERIFY); - if (ret != 0 || - ip->dbth_state == THREAD_FAILCHK) - return (DB_RUNRECOVERY); - } - if (!wait) - return (DB_LOCK_NOTGRANTED); - if (timeout != 0) { - timespecclear(&now); - if (__clock_expired(env, &now, ×pec)) - return (DB_TIMEOUT); - DB_TIMESPEC_TO_TIMEOUT(time_left, &now, 0); - time_left = timeout - time_left; - if (ms * US_PER_MS > time_left) - ms = time_left / US_PER_MS; - } - __os_yield(NULL, 0, ms * US_PER_MS); - if ((ms <<= 1) > MS_PER_SEC) - ms = MS_PER_SEC; - } - - /* Acquire an exclusive kernel lock on the byte. */ - k_lock.l_type = F_WRLCK; - if (fcntl(env->lockfhp->fd, F_SETLKW, &k_lock)) - goto err; - - /* If the resource is still available, it's ours. */ - if (!F_ISSET(mutexp, DB_MUTEX_LOCKED)) { - locked = 1; - - F_SET(mutexp, DB_MUTEX_LOCKED); - dbenv->thread_id(dbenv, &mutexp->pid, &mutexp->tid); - } - - /* Release the kernel lock. */ - k_lock.l_type = F_UNLCK; - if (fcntl(env->lockfhp->fd, F_SETLK, &k_lock)) - goto err; - - /* - * If we got the resource lock we're done. - * - * !!! - * We can't check to see if the lock is ours, because we may - * be trying to block ourselves in the lock manager, and so - * the holder of the lock that's preventing us from getting - * the lock may be us! (Seriously.) - */ - if (locked) - break; - } - -#ifdef DIAGNOSTIC - /* - * We want to switch threads as often as possible. Yield every time - * we get a mutex to ensure contention. - */ - if (F_ISSET(dbenv, DB_ENV_YIELDCPU)) - __os_yield(env, 0, 0); -#endif - return (0); - -err: ret = __os_get_syserr(); - __db_syserr(env, ret, DB_STR("2019", "fcntl lock failed")); - return (__env_panic(env, __os_posix_err(ret))); -} - -/* - * __db_fcntl_mutex_lock - * Lock a mutex, blocking if necessary. - * - * PUBLIC: int __db_fcntl_mutex_lock __P((ENV *, db_mutex_t, db_timeout_t)); - */ -int -__db_fcntl_mutex_lock(env, mutex, timeout) - ENV *env; - db_mutex_t mutex; - db_timeout_t timeout; -{ - return (__db_fcntl_mutex_lock_int(env, mutex, timeout, 1)); -} - -/* - * __db_fcntl_mutex_trylock - * Try to lock a mutex, without blocking when it is busy. - * - * PUBLIC: int __db_fcntl_mutex_trylock __P((ENV *, db_mutex_t)); - */ -int -__db_fcntl_mutex_trylock(env, mutex) - ENV *env; - db_mutex_t mutex; -{ - return (__db_fcntl_mutex_lock_int(env, mutex, 0, 0)); -} - -/* - * __db_fcntl_mutex_unlock -- - * Release a mutex. - * - * PUBLIC: int __db_fcntl_mutex_unlock __P((ENV *, db_mutex_t)); - */ -int -__db_fcntl_mutex_unlock(env, mutex) - ENV *env; - db_mutex_t mutex; -{ - DB_ENV *dbenv; - DB_MUTEX *mutexp; - - dbenv = env->dbenv; - - if (!MUTEX_ON(env) || F_ISSET(dbenv, DB_ENV_NOLOCKING)) - return (0); - - mutexp = MUTEXP_SET(env, mutex); - -#ifdef DIAGNOSTIC - if (!F_ISSET(mutexp, DB_MUTEX_LOCKED)) { - __db_errx(env, DB_STR("2020", - "fcntl unlock failed: lock already unlocked")); - return (__env_panic(env, EACCES)); - } -#endif - - /* - * Release the resource. We don't have to acquire any locks because - * processes trying to acquire the lock are waiting for the flag to - * go to 0. Once that happens the waiters will serialize acquiring - * an exclusive kernel lock before locking the mutex. - */ - F_CLR(mutexp, DB_MUTEX_LOCKED); - - return (0); -} - -/* - * __db_fcntl_mutex_destroy -- - * Destroy a mutex. - * - * PUBLIC: int __db_fcntl_mutex_destroy __P((ENV *, db_mutex_t)); - */ -int -__db_fcntl_mutex_destroy(env, mutex) - ENV *env; - db_mutex_t mutex; -{ - COMPQUIET(env, NULL); - COMPQUIET(mutex, MUTEX_INVALID); - - return (0); -} |