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/*
* ip tunnel/ethertap device for MacOSX.
*
* Locking implementation.
*/
/*
* Copyright (c) 2011 Mattias Nissler <mattias.nissler@gmx.de>
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other materials provided
* with the distribution.
* 3. The name of the author may not be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "lock.h"
extern "C" {
#include <kern/clock.h>
#include <sys/syslog.h>
#include <sys/proc.h>
}
#if 0
#define dprintf(...) log(LOG_INFO, __VA_ARGS__)
#else
#define dprintf(...)
#endif
/* class tt_lock */
lck_grp_t *tt_lock::tt_lck_grp = NULL;
bool
tt_lock::initialize()
{
/* init if necessary */
if (tt_lck_grp == NULL) {
dprintf("initing lock group\n");
tt_lck_grp = lck_grp_alloc_init("tuntap locks", LCK_GRP_ATTR_NULL);
if (tt_lck_grp == NULL) {
/* if something fails, the lock won't work */
log(LOG_ERR, "tuntap: could not allocate locking group\n");
return false;
}
}
return true;
}
void
tt_lock::shutdown()
{
/* free the locking group */
if (tt_lck_grp != NULL) {
dprintf("freeing lock group\n");
lck_grp_free(tt_lck_grp);
tt_lck_grp = NULL;
}
}
/* tt_mutex */
tt_mutex::tt_mutex()
{
/* fail if locking group not initialized */
if (tt_lck_grp == NULL)
return;
/* allocate the lock */
lck = lck_rw_alloc_init(tt_lck_grp, NULL);
if (lck == NULL)
log(LOG_ERR, "tuntap: could not allocate mutex\n");
}
tt_mutex::~tt_mutex()
{
/* if the lock doesn't exist, this will be a no-op */
if (lck == NULL)
return;
/* free the lock */
lck_rw_free(lck, tt_lck_grp);
}
void
tt_mutex::lock()
{
if (lck != NULL)
lck_rw_lock_exclusive(lck);
}
void
tt_mutex::unlock()
{
if (lck != NULL)
lck_rw_unlock_exclusive(lck);
}
void
tt_mutex::sleep(void *cond)
{
if (lck != NULL)
lck_rw_sleep(lck, LCK_SLEEP_DEFAULT, cond, THREAD_INTERRUPTIBLE);
}
void
tt_mutex::sleep(void *cond, uint64_t nanoseconds)
{
if (lck != NULL) {
uint64_t abstime;
nanoseconds_to_absolutetime(nanoseconds, &abstime);
lck_rw_sleep_deadline(lck, LCK_SLEEP_DEFAULT, cond, THREAD_INTERRUPTIBLE, abstime);
}
}
void
tt_mutex::wakeup(void *cond)
{
if (lck != NULL)
::wakeup(cond);
}
/* tt_gate */
tt_gate::tt_gate()
: ticket_number(0),
population(0)
{
}
void
tt_gate::enter()
{
/* just try to grab the lock, increase the ticket number and the population */
auto_lock l(&slock);
ticket_number++;
population++;
}
void
tt_gate::exit()
{
auto_lock l(&slock);
ticket_number--;
population--;
}
bool
tt_gate::is_anyone_in()
{
return population != 0;
}
unsigned int
tt_gate::get_ticket_number()
{
return ticket_number;
}
void
tt_gate::lock()
{
slock.lock();
}
void
tt_gate::unlock()
{
slock.unlock();
}
void
tt_gate::sleep(void* cond)
{
slock.sleep(cond);
}
void
tt_gate::sleep(void* cond, uint64_t nanoseconds)
{
slock.sleep(cond, nanoseconds);
}
void
tt_gate::wakeup(void* cond)
{
slock.wakeup(cond);
}
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