/**
* down_interruptible - acquire the semaphore unless interrupted
* @sem: the semaphore to be acquired
*
* Attempts to acquire the semaphore. If no more tasks are allowed to
* acquire the semaphore, calling this function will put the task to sleep.
* If the sleep is interrupted by a signal, this function will return -EINTR.
* If the semaphore is successfully acquired, this function returns 0.
*/
int down_interruptible(struct semaphore *sem)
{
unsigned long flags;
int result = 0;
spin_lock_irqsave(&sem->lock, flags);
if (likely(sem->count > 0)){
sem->count--;
}else{
#ifdef CONFIG_MT_LOCK_DEBUG
if(sem->owner == current){
char aee_str[40];
printk("[Warning!Recursive Semaphore!][%d:%s], down_interruptible:%s(0x%x)\n", current->pid, current->comm, sem->sem_name, sem);
sprintf( aee_str, "Recursive SemLock:%s\n", current->comm);
aee_kernel_warning( aee_str,"mtlock debugger\n");
dump_stack();
}
#endif
result = __down_interruptible(sem);
}
#ifdef CONFIG_MT_LOCK_DEBUG
if(0 == sem->count)
sem_set_owner(sem);
#endif
spin_unlock_irqrestore(&sem->lock, flags);
return result;
}
BaseGDL* sem_create(EnvT *e)
{
SizeT nParam = e->NParam(1); // 1 is the minimal number of parameter required
DString name;
e->AssureStringScalarPar(0, name); // IDL accepts null-string name
int destroyIx = e->KeywordIx("DESTROY_SEMAPHORE");
bool destroyKWPresent = e->KeywordPresent(destroyIx);
DLong destroy = 0;
if (destroyKWPresent)
{
destroy = (*e->GetKWAs<DLongGDL>(0))[0];
}
bool owner = true;
#if defined(_WIN32) && !defined(__CYGWIN__)
// TODO: Needs error handling with name length > 256
const char* cname = name.c_str();
WCHAR tname[256] = {0,};
MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, cname, strlen(cname), tname, 256);
HANDLE sem = CreateSemaphoreW(NULL,1,1,tname);
if (sem == NULL) {
owner = false;
return new DIntGDL(0);
}
#else
sem_t *sem = sem_open(name.c_str(), O_CREAT | O_EXCL, 0666, 1);
if (sem == SEM_FAILED)
{ // semaphore exists. make another one, locked (value=0)
owner = false;
if (errno == EEXIST)
{
sem = sem_open(name.c_str(), O_CREAT ,0666, 0);
}
if (sem == SEM_FAILED)
{
return new DIntGDL(0);
}
}
#endif
// Behavior for different values of DESTROY_SEMAPHORE:
// DESTROY_SEMAPHORE | owner | other (== !owner)
// ------------------+----------+-----------
// not set | delete | ignore
// != 0 | delete | delete
// 0 | ignore | ignore
sem_data_t data;
data.sem = sem;
sem_set_owner(data, owner);
sem_set_deletable(data, (!destroyKWPresent && owner) || (destroy != 0));
sem_set_locked(data, false);
sem_add(name, data);
return new DIntGDL(1);
}
BaseGDL* sem_create(EnvT *e)
{
SizeT nParam = e->NParam(1); // 1 is the minimal number of parameter required
DString name;
e->AssureStringScalarPar(0, name); // IDL accepts null-string name
int destroyIx = e->KeywordIx("DESTROY_SEMAPHORE");
bool destroyKWPresent = e->KeywordPresent(destroyIx);
DLong destroy = 0;
if (destroyKWPresent)
{
destroy = (*e->GetKWAs<DLongGDL>(0))[0];
}
bool owner = true;
#ifdef _MSC_VER
HANDLE sem = CreateSemaphore(NULL,1,1,name.c_str());
if (sem == NULL) {
owner = false;
return new DIntGDL(0);
}
#else
sem_t *sem = sem_open(name.c_str(), O_CREAT | O_EXCL, 0666, 1);
if (sem == SEM_FAILED)
{
owner = false;
if (errno == EEXIST)
{
sem = sem_open(name.c_str(), 0);
}
if (sem == SEM_FAILED)
{
return new DIntGDL(0);
}
}
#endif
// Behavior for different values of DESTROY_SEMAPHORE:
// DESTROY_SEMAPHORE | owner | other (== !owner)
// ------------------+----------+-----------
// not set | delete | ignore
// != 0 | delete | delete
// 0 | ignore | ignore
sem_data_t data;
data.sem = sem;
sem_set_owner(data, owner);
sem_set_deletable(data, (!destroyKWPresent && owner) || (destroy != 0));
sem_set_locked(data, false);
sem_add(name, data);
return new DIntGDL(1);
}
/**
* down_trylock - try to acquire the semaphore, without waiting
* @sem: the semaphore to be acquired
*
* Try to acquire the semaphore atomically. Returns 0 if the mutex has
* been acquired successfully or 1 if it it cannot be acquired.
*
* NOTE: This return value is inverted from both spin_trylock and
* mutex_trylock! Be careful about this when converting code.
*
* Unlike mutex_trylock, this function can be used from interrupt context,
* and the semaphore can be released by any task or interrupt.
*/
int down_trylock(struct semaphore *sem)
{
unsigned long flags;
int count;
spin_lock_irqsave(&sem->lock, flags);
count = sem->count - 1;
if (likely(count >= 0)){
sem->count = count;
#ifdef CONFIG_MT_LOCK_DEBUG
if(0 == sem->count)
sem_set_owner(sem);
#endif
}
spin_unlock_irqrestore(&sem->lock, flags);
return (count < 0);
}
