ntopng/src/RwLock.cpp
2019-10-28 11:17:19 +01:00

137 lines
3.6 KiB
C++

/*
*
* (C) 2013-19 - ntop.org
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include "ntop_includes.h"
//#define DEBUG_RW_LOCK
/* ******************************* */
RwLock::RwLock() {
#ifndef HAVE_RW_LOCK
Mutex m;
#else
pthread_rwlock_init(&the_rwlock, NULL);
#endif
}
/* ******************************* */
RwLock::~RwLock() {
#ifndef HAVE_RW_LOCK
/* Mutex destructor called automatically */
#else
pthread_rwlock_destroy(&the_rwlock);
#endif
}
/* ******************************* */
void RwLock::lock(const char *filename, int line, bool readonly) {
#ifndef HAVE_RW_LOCK
#ifdef DEBUG_RW_LOCK
ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s:%d] lock(%p)", filename, line, &m);
#endif
m.lock(filename, line);
#else
int rc;
if(readonly) {
#ifdef DEBUG_RW_LOCK
ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s:%d] lock(RO, %p)", filename, line, &the_rwlock);
#endif
rc = pthread_rwlock_rdlock(&the_rwlock);
} else {
#ifdef DEBUG_RW_LOCK
ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s:%d] lock(RW, %p)", filename, line, &the_rwlock);
#endif
rc = pthread_rwlock_wrlock(&the_rwlock);
}
if(rc)
ntop->getTrace()->traceEvent(TRACE_WARNING, "Unable to acquire lock. Return code %d [%s]", rc, strerror(rc), errno);
#endif
}
/* ******************************* */
bool RwLock::trylock(const char *filename, int line, bool readonly) {
#ifndef HAVE_RW_LOCK
m.lock(filename, line);
return true; /* Pretend to be always successful - indeed, if here the lock is acquired even in a blocking fashion */
#else
int rc;
if(readonly)
rc = pthread_rwlock_tryrdlock(&the_rwlock);
else
rc = pthread_rwlock_trywrlock(&the_rwlock);
if(!rc)
return true; /* Lock acquired successfully */
if(rc == EBUSY)
; /* Normal, lock is being held by someone else */
else
ntop->getTrace()->traceEvent(TRACE_NORMAL, "Unable to acquire lock. Return code %d [%s]", rc, strerror(rc));
return false; /* Lock not acquired, held by someone else or there was an error */
#endif
}
/* ******************************* */
void RwLock::rdlock(const char *filename, int line) {
lock(filename, line, true /* readonly */);
}
/* ******************************* */
void RwLock::wrlock(const char *filename, int line) {
lock(filename, line, false /* write */);
}
/* ******************************* */
bool RwLock::trywrlock(const char *filename, int line) {
return trylock(filename, line, false /* write */);
}
/* ******************************* */
void RwLock::unlock(const char *filename, int line) {
#ifndef HAVE_RW_LOCK
#ifdef DEBUG_RW_LOCK
ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s:%d] unlock(%p)", filename, line, &m);
#endif
m.unlock(filename, line);
#else
int rc;
#ifdef DEBUG_RW_LOCK
ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s:%d] unlock(%p)", filename, line, &the_rwlock);
#endif
rc = pthread_rwlock_unlock(&the_rwlock);
if(rc)
ntop->getTrace()->traceEvent(TRACE_WARNING, "pthread_rwlock_unlock() returned %d [%s]", rc, strerror(rc), errno);
#endif
}