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dd9b98986d
macro used unsigned, inline function int. This could lead to an unsigned overflow if macro version was used. That could potentially lead to malfunction on some platforms (not seen nor expected in practice, though). Detected by clang UBSAN.
244 lines
8.2 KiB
C
244 lines
8.2 KiB
C
/* This header supplies atomic operations. So far, we rely on GCC's
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* atomic builtins. During configure, we check if atomic operatons are
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* available. If they are not, I am making the necessary provisioning to live without them if
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* they are not available. Please note that you should only use the macros
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* here if you think you can actually live WITHOUT an explicit atomic operation,
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* because in the non-presence of them, we simply do it without atomicitiy.
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* Which, for word-aligned data types, usually (but only usually!) should work.
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*
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* We are using the functions described in
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* http:/gcc.gnu.org/onlinedocs/gcc/Atomic-Builtins.html
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*
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* THESE MACROS MUST ONLY BE USED WITH WORD-SIZED DATA TYPES!
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*
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* Copyright 2008-2012 Rainer Gerhards and Adiscon GmbH.
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*
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* This file is part of the rsyslog runtime library.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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* -or-
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* see COPYING.ASL20 in the source distribution
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef INCLUDED_ATOMIC_H
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#define INCLUDED_ATOMIC_H
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#include <time.h>
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#include "typedefs.h"
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/* for this release, we disable atomic calls because there seem to be some
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* portability problems and we can not fix that without destabilizing the build.
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* They simply came in too late. -- rgerhards, 2008-04-02
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*/
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#ifdef HAVE_ATOMIC_BUILTINS
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# define ATOMIC_SUB(data, val, phlpmut) __sync_fetch_and_sub(data, val)
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# define ATOMIC_ADD(data, val) __sync_fetch_and_add(&(data), val)
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# define ATOMIC_INC(data, phlpmut) ((void) __sync_fetch_and_add(data, 1))
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# define ATOMIC_INC_AND_FETCH_int(data, phlpmut) __sync_fetch_and_add(data, 1)
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# define ATOMIC_INC_AND_FETCH_unsigned(data, phlpmut) __sync_fetch_and_add(data, 1)
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# define ATOMIC_DEC(data, phlpmut) ((void) __sync_sub_and_fetch(data, 1))
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# define ATOMIC_DEC_AND_FETCH(data, phlpmut) __sync_sub_and_fetch(data, 1)
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# define ATOMIC_FETCH_32BIT(data, phlpmut) ((int) __sync_fetch_and_and(data, 0xffffffff))
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# define ATOMIC_STORE_1_TO_32BIT(data) __sync_lock_test_and_set(&(data), 1)
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# define ATOMIC_STORE_0_TO_INT(data, phlpmut) __sync_fetch_and_and(data, 0)
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# define ATOMIC_STORE_1_TO_INT(data, phlpmut) __sync_fetch_and_or(data, 1)
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# define ATOMIC_OR_INT_TO_INT(data, phlpmut, val) __sync_fetch_and_or((data), (val))
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# define ATOMIC_CAS(data, oldVal, newVal, phlpmut) __sync_bool_compare_and_swap(data, (oldVal), (newVal))
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# define ATOMIC_CAS_time_t(data, oldVal, newVal, phlpmut) __sync_bool_compare_and_swap(data, (oldVal), (newVal))
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# define ATOMIC_CAS_VAL(data, oldVal, newVal, phlpmut) __sync_val_compare_and_swap(data, (oldVal), (newVal));
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/* functions below are not needed if we have atomics */
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# define DEF_ATOMIC_HELPER_MUT(x)
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# define INIT_ATOMIC_HELPER_MUT(x)
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# define DESTROY_ATOMIC_HELPER_MUT(x)
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/* the following operations should preferrably be done atomic, but it is
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* not fatal if not -- that means we can live with some missed updates. So be
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* sure to use these macros only if that really does not matter!
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*/
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# define PREFER_ATOMIC_INC(data) ((void) __sync_fetch_and_add(&(data), 1))
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# define PREFER_FETCH_32BIT(data) ((unsigned) __sync_fetch_and_and(&(data), 0xffffffff))
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#else
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/* note that we gained parctical proof that theoretical problems DO occur
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* if we do not properly address them. See this blog post for details:
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* http://blog.gerhards.net/2009/01/rsyslog-data-race-analysis.html
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* The bottom line is that if there are no atomics available, we should NOT
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* simply go ahead and do without them - use mutexes or other things. The
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* code needs to be checked against all those cases. -- rgerhards, 2009-01-30
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*/
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#include <pthread.h>
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# define ATOMIC_INC(data, phlpmut) { \
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pthread_mutex_lock(phlpmut); \
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++(*(data)); \
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pthread_mutex_unlock(phlpmut); \
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}
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# define ATOMIC_STORE_0_TO_INT(data, hlpmut) { \
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pthread_mutex_lock(hlpmut); \
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*(data) = 0; \
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pthread_mutex_unlock(hlpmut); \
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}
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# define ATOMIC_STORE_1_TO_INT(data, hlpmut) { \
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pthread_mutex_lock(hlpmut); \
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*(data) = 1; \
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pthread_mutex_unlock(hlpmut); \
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}
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# define ATOMIC_OR_INT_TO_INT(data, hlpmut, val) { \
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pthread_mutex_lock(hlpmut); \
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*(data) = val; \
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pthread_mutex_unlock(hlpmut); \
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}
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static inline int
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ATOMIC_CAS(int *data, int oldVal, int newVal, pthread_mutex_t *phlpmut) {
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int bSuccess;
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pthread_mutex_lock(phlpmut);
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if(*data == oldVal) {
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*data = newVal;
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bSuccess = 1;
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} else {
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bSuccess = 0;
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}
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pthread_mutex_unlock(phlpmut);
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return(bSuccess);
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}
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static inline int
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ATOMIC_CAS_time_t(time_t *data, time_t oldVal, time_t newVal, pthread_mutex_t *phlpmut) {
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int bSuccess;
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pthread_mutex_lock(phlpmut);
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if(*data == oldVal) {
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*data = newVal;
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bSuccess = 1;
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} else {
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bSuccess = 0;
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}
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pthread_mutex_unlock(phlpmut);
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return(bSuccess);
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}
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static inline int
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ATOMIC_CAS_VAL(int *data, int oldVal, int newVal, pthread_mutex_t *phlpmut) {
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int val;
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pthread_mutex_lock(phlpmut);
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if(*data == oldVal) {
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*data = newVal;
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}
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val = *data;
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pthread_mutex_unlock(phlpmut);
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return(val);
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}
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# define ATOMIC_DEC(data, phlpmut) { \
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pthread_mutex_lock(phlpmut); \
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--(*(data)); \
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pthread_mutex_unlock(phlpmut); \
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}
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static inline int
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ATOMIC_INC_AND_FETCH_int(int *data, pthread_mutex_t *phlpmut) {
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int val;
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pthread_mutex_lock(phlpmut);
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val = ++(*data);
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pthread_mutex_unlock(phlpmut);
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return(val);
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}
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static inline unsigned
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ATOMIC_INC_AND_FETCH_unsigned(unsigned *data, pthread_mutex_t *phlpmut) {
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unsigned val;
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pthread_mutex_lock(phlpmut);
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val = ++(*data);
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pthread_mutex_unlock(phlpmut);
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return(val);
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}
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static inline int
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ATOMIC_DEC_AND_FETCH(int *data, pthread_mutex_t *phlpmut) {
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int val;
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pthread_mutex_lock(phlpmut);
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val = --(*data);
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pthread_mutex_unlock(phlpmut);
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return(val);
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}
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static inline int
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ATOMIC_FETCH_32BIT(int *data, pthread_mutex_t *phlpmut) {
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int val;
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pthread_mutex_lock(phlpmut);
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val = (*data);
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pthread_mutex_unlock(phlpmut);
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return(val);
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}
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static inline void
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ATOMIC_SUB(int *data, int val, pthread_mutex_t *phlpmut) {
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pthread_mutex_lock(phlpmut);
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(*data) -= val;
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pthread_mutex_unlock(phlpmut);
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}
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# define DEF_ATOMIC_HELPER_MUT(x) pthread_mutex_t x;
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# define INIT_ATOMIC_HELPER_MUT(x) pthread_mutex_init(&(x), NULL);
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# define DESTROY_ATOMIC_HELPER_MUT(x) pthread_mutex_destroy(&(x));
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# define PREFER_ATOMIC_INC(data) ((void) ++data)
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# define PREFER_FETCH_32BIT(data) ((unsigned) (data))
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#endif
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/* we need to handle 64bit atomics seperately as some platforms have
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* 32 bit atomics, but not 64 bit ones... -- rgerhards, 2010-12-01
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*/
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#ifdef HAVE_ATOMIC_BUILTINS64
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# define ATOMIC_INC_uint64(data, phlpmut) ((void) __sync_fetch_and_add(data, 1))
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# define ATOMIC_ADD_uint64(data, phlpmut, value) ((void) __sync_fetch_and_add(data, value))
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# define ATOMIC_DEC_unit64(data, phlpmut) ((void) __sync_sub_and_fetch(data, 1))
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# define ATOMIC_INC_AND_FETCH_uint64(data, phlpmut) __sync_fetch_and_add(data, 1)
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# define DEF_ATOMIC_HELPER_MUT64(x)
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# define INIT_ATOMIC_HELPER_MUT64(x)
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# define DESTROY_ATOMIC_HELPER_MUT64(x)
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#else
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# define ATOMIC_INC_uint64(data, phlpmut) { \
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pthread_mutex_lock(phlpmut); \
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++(*(data)); \
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pthread_mutex_unlock(phlpmut); \
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}
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# define ATOMIC_ADD_uint64(data, phlpmut, value) { \
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pthread_mutex_lock(phlpmut); \
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*data += value; \
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pthread_mutex_unlock(phlpmut); \
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}
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# define ATOMIC_DEC_uint64(data, phlpmut) { \
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pthread_mutex_lock(phlpmut); \
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--(*(data)); \
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pthread_mutex_unlock(phlpmut); \
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}
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static inline unsigned
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ATOMIC_INC_AND_FETCH_uint64(uint64 *data, pthread_mutex_t *phlpmut) {
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uint64 val;
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pthread_mutex_lock(phlpmut);
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val = ++(*data);
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pthread_mutex_unlock(phlpmut);
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return(val);
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}
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# define DEF_ATOMIC_HELPER_MUT64(x) pthread_mutex_t x;
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# define INIT_ATOMIC_HELPER_MUT64(x) pthread_mutex_init(&(x), NULL)
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# define DESTROY_ATOMIC_HELPER_MUT64(x) pthread_mutex_destroy(&(x))
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#endif /* #ifdef HAVE_ATOMIC_BUILTINS64 */
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#endif /* #ifndef INCLUDED_ATOMIC_H */
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