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Diffstat (limited to 'contrib/bind9/lib/isc/rwlock.c')
-rw-r--r--contrib/bind9/lib/isc/rwlock.c427
1 files changed, 0 insertions, 427 deletions
diff --git a/contrib/bind9/lib/isc/rwlock.c b/contrib/bind9/lib/isc/rwlock.c
deleted file mode 100644
index 3e444d8a1125..000000000000
--- a/contrib/bind9/lib/isc/rwlock.c
+++ /dev/null
@@ -1,427 +0,0 @@
-/*
- * Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC")
- * Copyright (C) 1998-2001, 2003 Internet Software Consortium.
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
- * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
- * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
- * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
- * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
- * PERFORMANCE OF THIS SOFTWARE.
- */
-
-/* $Id: rwlock.c,v 1.33.2.4.2.3 2005/03/17 03:58:32 marka Exp $ */
-
-#include <config.h>
-
-#include <stddef.h>
-
-#include <isc/magic.h>
-#include <isc/msgs.h>
-#include <isc/platform.h>
-#include <isc/rwlock.h>
-#include <isc/util.h>
-
-#define RWLOCK_MAGIC ISC_MAGIC('R', 'W', 'L', 'k')
-#define VALID_RWLOCK(rwl) ISC_MAGIC_VALID(rwl, RWLOCK_MAGIC)
-
-#ifdef ISC_PLATFORM_USETHREADS
-
-#ifndef RWLOCK_DEFAULT_READ_QUOTA
-#define RWLOCK_DEFAULT_READ_QUOTA 4
-#endif
-
-#ifndef RWLOCK_DEFAULT_WRITE_QUOTA
-#define RWLOCK_DEFAULT_WRITE_QUOTA 4
-#endif
-
-#ifdef ISC_RWLOCK_TRACE
-#include <stdio.h> /* Required for fprintf/stderr. */
-#include <isc/thread.h> /* Requried for isc_thread_self(). */
-
-static void
-print_lock(const char *operation, isc_rwlock_t *rwl, isc_rwlocktype_t type) {
- fprintf(stderr,
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_PRINTLOCK,
- "rwlock %p thread %lu %s(%s): %s, %u active, "
- "%u granted, %u rwaiting, %u wwaiting\n"),
- rwl, isc_thread_self(), operation,
- (type == isc_rwlocktype_read ?
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_READ, "read") :
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_WRITE, "write")),
- (rwl->type == isc_rwlocktype_read ?
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_READING, "reading") :
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_WRITING, "writing")),
- rwl->active, rwl->granted, rwl->readers_waiting,
- rwl->writers_waiting);
-}
-#endif
-
-isc_result_t
-isc_rwlock_init(isc_rwlock_t *rwl, unsigned int read_quota,
- unsigned int write_quota)
-{
- isc_result_t result;
-
- REQUIRE(rwl != NULL);
-
- /*
- * In case there's trouble initializing, we zero magic now. If all
- * goes well, we'll set it to RWLOCK_MAGIC.
- */
- rwl->magic = 0;
-
- rwl->type = isc_rwlocktype_read;
- rwl->original = isc_rwlocktype_none;
- rwl->active = 0;
- rwl->granted = 0;
- rwl->readers_waiting = 0;
- rwl->writers_waiting = 0;
- if (read_quota == 0)
- read_quota = RWLOCK_DEFAULT_READ_QUOTA;
- rwl->read_quota = read_quota;
- if (write_quota == 0)
- write_quota = RWLOCK_DEFAULT_WRITE_QUOTA;
- rwl->write_quota = write_quota;
- result = isc_mutex_init(&rwl->lock);
- if (result != ISC_R_SUCCESS) {
- UNEXPECTED_ERROR(__FILE__, __LINE__,
- "isc_mutex_init() %s: %s",
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
- ISC_MSG_FAILED, "failed"),
- isc_result_totext(result));
- return (ISC_R_UNEXPECTED);
- }
- result = isc_condition_init(&rwl->readable);
- if (result != ISC_R_SUCCESS) {
- UNEXPECTED_ERROR(__FILE__, __LINE__,
- "isc_condition_init(readable) %s: %s",
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
- ISC_MSG_FAILED, "failed"),
- isc_result_totext(result));
- result = ISC_R_UNEXPECTED;
- goto destroy_lock;
-
- }
- result = isc_condition_init(&rwl->writeable);
- if (result != ISC_R_SUCCESS) {
- UNEXPECTED_ERROR(__FILE__, __LINE__,
- "isc_condition_init(writeable) %s: %s",
- isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
- ISC_MSG_FAILED, "failed"),
- isc_result_totext(result));
- result = ISC_R_UNEXPECTED;
- goto destroy_rcond;
- }
-
- rwl->magic = RWLOCK_MAGIC;
-
- return (ISC_R_SUCCESS);
-
- destroy_rcond:
- (void)isc_condition_destroy(&rwl->readable);
- destroy_lock:
- DESTROYLOCK(&rwl->lock);
-
- return (result);
-}
-
-static isc_result_t
-doit(isc_rwlock_t *rwl, isc_rwlocktype_t type, isc_boolean_t nonblock) {
- isc_boolean_t skip = ISC_FALSE;
- isc_boolean_t done = ISC_FALSE;
- isc_result_t result = ISC_R_SUCCESS;
-
- REQUIRE(VALID_RWLOCK(rwl));
-
- LOCK(&rwl->lock);
-
-#ifdef ISC_RWLOCK_TRACE
- print_lock(isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_PRELOCK, "prelock"), rwl, type);
-#endif
-
- if (type == isc_rwlocktype_read) {
- if (rwl->readers_waiting != 0)
- skip = ISC_TRUE;
- while (!done) {
- if (!skip &&
- ((rwl->active == 0 ||
- (rwl->type == isc_rwlocktype_read &&
- (rwl->writers_waiting == 0 ||
- rwl->granted < rwl->read_quota)))))
- {
- rwl->type = isc_rwlocktype_read;
- rwl->active++;
- rwl->granted++;
- done = ISC_TRUE;
- } else if (nonblock) {
- result = ISC_R_LOCKBUSY;
- done = ISC_TRUE;
- } else {
- skip = ISC_FALSE;
- rwl->readers_waiting++;
- WAIT(&rwl->readable, &rwl->lock);
- rwl->readers_waiting--;
- }
- }
- } else {
- if (rwl->writers_waiting != 0)
- skip = ISC_TRUE;
- while (!done) {
- if (!skip && rwl->active == 0) {
- rwl->type = isc_rwlocktype_write;
- rwl->active = 1;
- rwl->granted++;
- done = ISC_TRUE;
- } else if (nonblock) {
- result = ISC_R_LOCKBUSY;
- done = ISC_TRUE;
- } else {
- skip = ISC_FALSE;
- rwl->writers_waiting++;
- WAIT(&rwl->writeable, &rwl->lock);
- rwl->writers_waiting--;
- }
- }
- }
-
-#ifdef ISC_RWLOCK_TRACE
- print_lock(isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_POSTLOCK, "postlock"), rwl, type);
-#endif
-
- UNLOCK(&rwl->lock);
-
- return (result);
-}
-
-isc_result_t
-isc_rwlock_lock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
- return (doit(rwl, type, ISC_FALSE));
-}
-
-isc_result_t
-isc_rwlock_trylock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
- return (doit(rwl, type, ISC_TRUE));
-}
-
-isc_result_t
-isc_rwlock_tryupgrade(isc_rwlock_t *rwl) {
- isc_result_t result = ISC_R_SUCCESS;
-
- REQUIRE(VALID_RWLOCK(rwl));
- LOCK(&rwl->lock);
- REQUIRE(rwl->type == isc_rwlocktype_read);
- REQUIRE(rwl->active != 0);
-
- /* If we are the only reader then succeed. */
- if (rwl->active == 1) {
- rwl->original = (rwl->original == isc_rwlocktype_none) ?
- isc_rwlocktype_read : isc_rwlocktype_none;
- rwl->type = isc_rwlocktype_write;
- } else
- result = ISC_R_LOCKBUSY;
-
- UNLOCK(&rwl->lock);
- return (result);
-}
-
-void
-isc_rwlock_downgrade(isc_rwlock_t *rwl) {
-
- REQUIRE(VALID_RWLOCK(rwl));
- LOCK(&rwl->lock);
- REQUIRE(rwl->type == isc_rwlocktype_write);
- REQUIRE(rwl->active == 1);
-
- rwl->type = isc_rwlocktype_read;
- rwl->original = (rwl->original == isc_rwlocktype_none) ?
- isc_rwlocktype_write : isc_rwlocktype_none;
- /*
- * Resume processing any read request that were blocked when
- * we upgraded.
- */
- if (rwl->original == isc_rwlocktype_none &&
- (rwl->writers_waiting == 0 || rwl->granted < rwl->read_quota) &&
- rwl->readers_waiting > 0)
- BROADCAST(&rwl->readable);
-
- UNLOCK(&rwl->lock);
-}
-
-isc_result_t
-isc_rwlock_unlock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
-
- REQUIRE(VALID_RWLOCK(rwl));
- LOCK(&rwl->lock);
- REQUIRE(rwl->type == type);
-
- UNUSED(type);
-
-#ifdef ISC_RWLOCK_TRACE
- print_lock(isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_PREUNLOCK, "preunlock"), rwl, type);
-#endif
-
- INSIST(rwl->active > 0);
- rwl->active--;
- if (rwl->active == 0) {
- if (rwl->original != isc_rwlocktype_none) {
- rwl->type = rwl->original;
- rwl->original = isc_rwlocktype_none;
- }
- if (rwl->type == isc_rwlocktype_read) {
- rwl->granted = 0;
- if (rwl->writers_waiting > 0) {
- rwl->type = isc_rwlocktype_write;
- SIGNAL(&rwl->writeable);
- } else if (rwl->readers_waiting > 0) {
- /* Does this case ever happen? */
- BROADCAST(&rwl->readable);
- }
- } else {
- if (rwl->readers_waiting > 0) {
- if (rwl->writers_waiting > 0 &&
- rwl->granted < rwl->write_quota) {
- SIGNAL(&rwl->writeable);
- } else {
- rwl->granted = 0;
- rwl->type = isc_rwlocktype_read;
- BROADCAST(&rwl->readable);
- }
- } else if (rwl->writers_waiting > 0) {
- rwl->granted = 0;
- SIGNAL(&rwl->writeable);
- } else {
- rwl->granted = 0;
- }
- }
- }
- INSIST(rwl->original == isc_rwlocktype_none);
-
-#ifdef ISC_RWLOCK_TRACE
- print_lock(isc_msgcat_get(isc_msgcat, ISC_MSGSET_RWLOCK,
- ISC_MSG_POSTUNLOCK, "postunlock"),
- rwl, type);
-#endif
-
- UNLOCK(&rwl->lock);
-
- return (ISC_R_SUCCESS);
-}
-
-void
-isc_rwlock_destroy(isc_rwlock_t *rwl) {
- REQUIRE(VALID_RWLOCK(rwl));
-
- LOCK(&rwl->lock);
- REQUIRE(rwl->active == 0 &&
- rwl->readers_waiting == 0 &&
- rwl->writers_waiting == 0);
- UNLOCK(&rwl->lock);
-
- rwl->magic = 0;
- (void)isc_condition_destroy(&rwl->readable);
- (void)isc_condition_destroy(&rwl->writeable);
- DESTROYLOCK(&rwl->lock);
-}
-
-#else /* ISC_PLATFORM_USETHREADS */
-
-isc_result_t
-isc_rwlock_init(isc_rwlock_t *rwl, unsigned int read_quota,
- unsigned int write_quota)
-{
- REQUIRE(rwl != NULL);
-
- UNUSED(read_quota);
- UNUSED(write_quota);
-
- rwl->type = isc_rwlocktype_read;
- rwl->active = 0;
- rwl->magic = RWLOCK_MAGIC;
-
- return (ISC_R_SUCCESS);
-}
-
-isc_result_t
-isc_rwlock_lock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
- REQUIRE(VALID_RWLOCK(rwl));
-
- if (type == isc_rwlocktype_read) {
- if (rwl->type != isc_rwlocktype_read && rwl->active != 0)
- return (ISC_R_LOCKBUSY);
- rwl->type = isc_rwlocktype_read;
- rwl->active++;
- } else {
- if (rwl->active != 0)
- return (ISC_R_LOCKBUSY);
- rwl->type = isc_rwlocktype_write;
- rwl->active = 1;
- }
- return (ISC_R_SUCCESS);
-}
-
-isc_result_t
-isc_rwlock_trylock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
- return (isc_rwlock_lock(rwl, type));
-}
-
-isc_result_t
-isc_rwlock_tryupgrade(isc_rwlock_t *rwl) {
- isc_result_t result = ISC_R_SUCCESS;
-
- REQUIRE(VALID_RWLOCK(rwl));
- REQUIRE(rwl->type == isc_rwlocktype_read);
- REQUIRE(rwl->active != 0);
-
- /* If we are the only reader then succeed. */
- if (rwl->active == 1)
- rwl->type = isc_rwlocktype_write;
- else
- result = ISC_R_LOCKBUSY;
- return (result);
-}
-
-void
-isc_rwlock_downgrade(isc_rwlock_t *rwl) {
-
- REQUIRE(VALID_RWLOCK(rwl));
- REQUIRE(rwl->type == isc_rwlocktype_write);
- REQUIRE(rwl->active == 1);
-
- rwl->type = isc_rwlocktype_read;
-}
-
-isc_result_t
-isc_rwlock_unlock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
- REQUIRE(VALID_RWLOCK(rwl));
- REQUIRE(rwl->type == type);
-
- UNUSED(type);
-
- INSIST(rwl->active > 0);
- rwl->active--;
-
- return (ISC_R_SUCCESS);
-}
-
-void
-isc_rwlock_destroy(isc_rwlock_t *rwl) {
- REQUIRE(rwl != NULL);
- REQUIRE(rwl->active == 0);
- rwl->magic = 0;
-}
-
-#endif /* ISC_PLATFORM_USETHREADS */
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