void
qlock(QLock *q)
{
Proc *up = externup();
Proc *p;
uint64_t t0;
cycles(&t0);
if(!islo() && machp()->ilockdepth != 0){
print("qlock with ilockdepth %d,", machp()->ilockdepth);
stacksnippet();
}
if(up != nil && up->nlocks)
print("qlock: %#p: nlocks %d", getcallerpc(&q), up->nlocks);
if(!canlock(&q->use)){
lock(&q->use);
slockstat(getcallerpc(&q), t0);
}
qlockstats.qlock++;
if(!q->locked) {
q->locked = 1;
q->pc = getcallerpc(&q);
unlock(&q->use);
return;
}
if(up == nil)
panic("qlock");
qlockstats.qlockq++;
p = q->tail;
if(p == 0)
q->head = up;
else
p->qnext = up;
q->tail = up;
up->qnext = 0;
up->state = Queueing;
up->qpc = getcallerpc(&q);
if(up->trace)
proctrace(up, SLock, 0);
unlock(&q->use);
sched();
lockstat(getcallerpc(&q), t0);
}
void
wlock(RWlock *q)
{
Proc *up = externup();
Proc *p;
uint64_t t0;
cycles(&t0);
if(!canlock(&q->use)){
lock(&q->use);
slockstat(getcallerpc(&q), t0);
}
qlockstats.wlock++;
if(q->readers == 0 && q->writer == 0){
/* noone waiting, go for it */
q->wpc = getcallerpc(&q);
q->wproc = up;
q->writer = 1;
unlock(&q->use);
return;
}
/* wait */
qlockstats.wlockq++;
p = q->tail;
if(up == nil)
panic("wlock");
if(p == nil)
q->head = up;
else
p->qnext = up;
q->tail = up;
up->qnext = 0;
up->state = QueueingW;
if(up->trace)
proctrace(up, SLock, 0);
unlock(&q->use);
sched();
lockstat(getcallerpc(&q), t0);
}
int
main( int argc, char * argv[] )
{
if( (App = new AppParam( argc, argv, VERID_main ) ) == 0 )
{
cerr << "Can't new AppParam." << endl;
exit( 1 );
}
if( ! App->good() || App->help() || ! App->allArgs() )
App->abort( 1, true, __FILE__, __LINE__ );
FileStat lockstat( App->lockFn() );
if( ! lockstat.good() )
{
AppError << lockstat.error() << endl;
return( 1 );
}
Semaphore sem( App->lockFn() );
if( ! sem.good() )
{
AppError << sem.error() << endl;
return( 1 );
}
FileLock lock( App->lockFn(), (ios::openmode)(ios::in | ios::out) );
if( ! lock.good() )
{
AppError << lock.error() << endl;
return( 1 );
}
if( ! sem.islocked() )
{
if( ! lock.lockread() )
{
AppError << lock.error() << endl;
return( 1 );
}
}
for( ;; )
{
AppDebug << "Sleeping for '" << App->sleepTime() << "' seconds." << endl;
sleep( App->sleepTime() );
if( sem.islocked() )
{
AppDebug << "sem LOCKED." << endl;
if( ! lock.unlock() )
{
AppError << lock.error() << endl;
return( 1 );
}
else
{
AppDebug << "read UNLOCKED." << endl;
}
if( ! sem.waitfor() )
{
AppError << sem.error() << endl;
}
if( ! lock.lockread() )
{
AppError << lock.error() << endl;
return( 1 );
}
else
{
AppDebug << "read LOCKED." << endl;
}
if( sem.islocked() )
{
AppError << "still LOCKED!!!" << endl;
return( 1 );
}
AppDebug << "sem UNLOCKED." << endl;
}
}
return( 0 );
}
