diff options
| -rw-r--r-- | configure.ac | 4 | ||||
| -rw-r--r-- | runtime/Makefile.am | 1 | ||||
| -rw-r--r-- | runtime/atomic-posix-sem.c | 70 | ||||
| -rw-r--r-- | runtime/atomic.h | 117 | ||||
| -rw-r--r-- | runtime/rsyslog.c | 14 |
5 files changed, 205 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac index c59895d7..ca198ea4 100644 --- a/configure.ac +++ b/configure.ac @@ -87,6 +87,7 @@ AC_TYPE_UINT8_T AC_HEADER_TIME AC_STRUCT_TM AC_C_VOLATILE +AC_C_TYPEOF sa_includes="\ $ac_includes_default @@ -129,7 +130,8 @@ AC_TRY_COMPILE([ # check for availability of atomic operations RS_ATOMIC_OPERATIONS RS_ATOMIC_OPERATIONS_64BIT - +# fall back to POSIX sems for atomic operations (cpu expensive) +AC_CHECK_HEADERS([semaphore.h]) # Additional module directories AC_ARG_WITH(moddirs, diff --git a/runtime/Makefile.am b/runtime/Makefile.am index 9047c83d..2374c575 100644 --- a/runtime/Makefile.am +++ b/runtime/Makefile.am @@ -9,6 +9,7 @@ librsyslog_la_SOURCES = \ rsyslog.h \ unicode-helper.h \ atomic.h \ + atomic-posix-sem.c \ batch.h \ syslogd-types.h \ module-template.h \ diff --git a/runtime/atomic-posix-sem.c b/runtime/atomic-posix-sem.c new file mode 100644 index 00000000..979fae02 --- /dev/null +++ b/runtime/atomic-posix-sem.c @@ -0,0 +1,70 @@ +/* atomic_posix_sem.c: This file supplies an emulation for atomic operations using + * POSIX semaphores. + * + * Copyright 2010 DResearch Digital Media Systems GmbH + * + * This file is part of the rsyslog runtime library. + * + * The rsyslog runtime library is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * The rsyslog runtime library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the rsyslog runtime library. If not, see <http://www.gnu.org/licenses/>. + * + * A copy of the GPL can be found in the file "COPYING" in this distribution. + * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution. + */ + +#include "config.h" +#ifndef HAVE_ATOMIC_BUILTINS +#ifdef HAVE_SEMAPHORE_H +#include <semaphore.h> +#include <errno.h> + +#include "atomic.h" +#include "rsyslog.h" +#include "srUtils.h" + +sem_t atomicSem; + +rsRetVal +atomicSemInit(void) +{ + DEFiRet; + + dbgprintf("init posix semaphore for atomics emulation\n"); + if(sem_init(&atomicSem, 0, 1) == -1) + { + char errStr[1024]; + rs_strerror_r(errno, errStr, sizeof(errStr)); + dbgprintf("init posix semaphore for atomics emulation failed: %s\n", errStr); + iRet = RS_RET_SYS_ERR; /* the right error code ??? */ + } + + RETiRet; +} + +void +atomicSemExit(void) +{ + dbgprintf("destroy posix semaphore for atomics emulation\n"); + if(sem_destroy(&atomicSem) == -1) + { + char errStr[1024]; + rs_strerror_r(errno, errStr, sizeof(errStr)); + dbgprintf("destroy posix semaphore for atomics emulation failed: %s\n", errStr); + } +} + +#endif /* HAVE_SEMAPHORE_H */ +#endif /* !defined(HAVE_ATOMIC_BUILTINS) */ + +/* vim:set ai: + */ diff --git a/runtime/atomic.h b/runtime/atomic.h index b507b769..51b14e18 100644 --- a/runtime/atomic.h +++ b/runtime/atomic.h @@ -54,6 +54,122 @@ # define ATOMIC_CAS(data, oldVal, newVal) __sync_bool_compare_and_swap(&(data), (oldVal), (newVal)); # define ATOMIC_CAS_VAL(data, oldVal, newVal) __sync_val_compare_and_swap(&(data), (oldVal), (newVal)); #else +#ifdef HAVE_SEMAPHORE_H + /* we use POSIX semaphores instead */ + +#include "rsyslog.h" +#include <semaphore.h> + +extern sem_t atomicSem; +rsRetVal atomicSemInit(void); +void atomicSemExit(void); + +#if HAVE_TYPEOF +#define my_typeof(x) typeof(x) +#else /* sorry, can't determine types, using 'int' */ +#define my_typeof(x) int +#endif + +# define ATOMIC_SUB(data, val) \ +({ \ + my_typeof(data) tmp; \ + sem_wait(&atomicSem); \ + tmp = data; \ + data -= val; \ + sem_post(&atomicSem); \ + tmp; \ +}) + +# define ATOMIC_ADD(data, val) \ +({ \ + my_typeof(data) tmp; \ + sem_wait(&atomicSem); \ + tmp = data; \ + data += val; \ + sem_post(&atomicSem); \ + tmp; \ +}) + +# define ATOMIC_INC_AND_FETCH(data) \ +({ \ + my_typeof(data) tmp; \ + sem_wait(&atomicSem); \ + tmp = data; \ + data += 1; \ + sem_post(&atomicSem); \ + tmp; \ +}) + +# define ATOMIC_INC(data) ((void) ATOMIC_INC_AND_FETCH(data)) + +# define ATOMIC_DEC_AND_FETCH(data) \ +({ \ + sem_wait(&atomicSem); \ + data -= 1; \ + sem_post(&atomicSem); \ + data; \ +}) + +# define ATOMIC_DEC(data) ((void) ATOMIC_DEC_AND_FETCH(data)) + +# define ATOMIC_FETCH_32BIT(data) ((unsigned) ATOMIC_ADD((data), 0xffffffff)) + +# define ATOMIC_STORE_1_TO_32BIT(data) \ +({ \ + my_typeof(data) tmp; \ + sem_wait(&atomicSem); \ + tmp = data; \ + data = 1; \ + sem_post(&atomicSem); \ + tmp; \ +}) + +# define ATOMIC_STORE_0_TO_INT(data) \ +({ \ + my_typeof(data) tmp; \ + sem_wait(&atomicSem); \ + tmp = data; \ + data = 0; \ + sem_post(&atomicSem); \ + tmp; \ +}) + +# define ATOMIC_STORE_1_TO_INT(data) \ +({ \ + my_typeof(data) tmp; \ + sem_wait(&atomicSem); \ + tmp = data; \ + data = 1; \ + sem_post(&atomicSem); \ + tmp; \ +}) + +# define ATOMIC_CAS(data, oldVal, newVal) \ +({ \ + int ret; \ + sem_wait(&atomicSem); \ + if(data != oldVal) ret = 0; \ + else \ + { \ + data = newVal; \ + ret = 1; \ + } \ + sem_post(&atomicSem); \ + ret; \ +}) + +# define ATOMIC_CAS_VAL(data, oldVal, newVal) \ +({ \ + sem_wait(&atomicSem); \ + if(data == oldVal) \ + { \ + data = newVal; \ + } \ + sem_post(&atomicSem); \ + data; \ +}) + +#else /* not HAVE_SEMAPHORE_H */ /* note that we gained parctical proof that theoretical problems DO occur * if we do not properly address them. See this blog post for details: * http://blog.gerhards.net/2009/01/rsyslog-data-race-analysis.html @@ -68,5 +184,6 @@ # define ATOMIC_FETCH_32BIT(data) (data) # define ATOMIC_STORE_1_TO_32BIT(data) (data) = 1 #endif +#endif #endif /* #ifndef INCLUDED_ATOMIC_H */ diff --git a/runtime/rsyslog.c b/runtime/rsyslog.c index a76ae25a..921ad0bd 100644 --- a/runtime/rsyslog.c +++ b/runtime/rsyslog.c @@ -81,6 +81,7 @@ #include "rule.h" #include "ruleset.h" #include "parser.h" +#include "atomic.h" /* forward definitions */ static rsRetVal dfltErrLogger(int, uchar *errMsg); @@ -140,6 +141,12 @@ rsrtInit(char **ppErrObj, obj_if_t *pObjIF) CHKiRet(objClassInit(NULL)); /* *THIS* *MUST* always be the first class initilizer being called! */ CHKiRet(objGetObjInterface(pObjIF)); /* this provides the root pointer for all other queries */ +#ifndef HAVE_ATOMIC_BUILTINS +#ifdef HAVE_SEMAPHORE_H + CHKiRet(atomicSemInit()); +#endif /* HAVE_SEMAPHORE_H */ +#endif /* !defined(HAVE_ATOMIC_BUILTINS) */ + /* initialize core classes. We must be very careful with the order of events. Some * classes use others and if we do not initialize them in the right order, we may end * up with an invalid call. The most important thing that can happen is that an error @@ -216,6 +223,13 @@ rsrtExit(void) glblClassExit(); rulesetClassExit(); ruleClassExit(); + +#ifndef HAVE_ATOMIC_BUILTINS +#ifdef HAVE_SEMAPHORE_H + atomicSemExit(); +#endif /* HAVE_SEMAPHORE_H */ +#endif /* !defined(HAVE_ATOMIC_BUILTINS) */ + objClassExit(); /* *THIS* *MUST/SHOULD?* always be the first class initilizer being called (except debug)! */ } |