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#include <minix/mthread.h>
#include "global.h"
#include "proto.h"
#ifdef MTHREAD_STRICT
static struct __mthread_cond *vc_front, *vc_rear;
static void mthread_cond_add(mthread_cond_t *c);
static void mthread_cond_remove(mthread_cond_t *c);
static int mthread_cond_valid(mthread_cond_t *c);
#else
# define mthread_cond_add(c) ((*c)->mc_magic = MTHREAD_INIT_MAGIC)
# define mthread_cond_remove(c) ((*c)->mc_magic = MTHREAD_NOT_INUSE)
# define mthread_cond_valid(c) ((*c)->mc_magic == MTHREAD_INIT_MAGIC)
#endif
#define MAIN_COND mainthread.m_cond
/*===========================================================================*
* mthread_init_valid_conditions *
*===========================================================================*/
void mthread_init_valid_conditions(void)
{
#ifdef MTHREAD_STRICT
/* Initialize condition variable list */
vc_front = vc_rear = NULL;
#endif
}
/*===========================================================================*
* mthread_cond_add *
*===========================================================================*/
#ifdef MTHREAD_STRICT
static void mthread_cond_add(c)
mthread_cond_t *c;
{
/* Add condition to list of valid, initialized conditions */
if (vc_front == NULL) { /* Empty list */
vc_front = *c;
(*c)->mc_prev = NULL;
} else {
vc_rear->mc_next = *c;
(*c)->mc_prev = vc_rear;
}
(*c)->mc_next = NULL;
vc_rear = *c;
}
#endif
/*===========================================================================*
* mthread_cond_broadcast *
*===========================================================================*/
int mthread_cond_broadcast(cond)
mthread_cond_t *cond;
{
/* Signal all threads waiting for condition 'cond'. */
mthread_thread_t t;
mthread_tcb_t *tcb;
if (cond == NULL)
return(EINVAL);
else if (!mthread_cond_valid(cond))
return(EINVAL);
tcb = mthread_find_tcb(MAIN_THREAD);
if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
mthread_unsuspend(MAIN_THREAD);
for (t = (mthread_thread_t) 0; t < no_threads; t++) {
tcb = mthread_find_tcb(t);
if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
mthread_unsuspend(t);
}
return(0);
}
/*===========================================================================*
* mthread_cond_destroy *
*===========================================================================*/
int mthread_cond_destroy(cond)
mthread_cond_t *cond;
{
/* Destroy a condition variable. Make sure it's not in use */
mthread_thread_t t;
mthread_tcb_t *tcb;
if (cond == NULL)
return(EINVAL);
else if (!mthread_cond_valid(cond))
return(EINVAL);
/* Is another thread currently using this condition variable? */
tcb = mthread_find_tcb(MAIN_THREAD);
if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
return(EBUSY);
for (t = (mthread_thread_t) 0; t < no_threads; t++) {
tcb = mthread_find_tcb(t);
if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
return(EBUSY);
}
/* Not in use; invalidate it. */
mthread_cond_remove(cond);
free(*cond);
*cond = NULL;
return(0);
}
/*===========================================================================*
* mthread_cond_init *
*===========================================================================*/
int mthread_cond_init(cond, cattr)
mthread_cond_t *cond;
mthread_condattr_t *cattr;
{
/* Initialize condition variable to a known state. cattr is ignored */
struct __mthread_cond *c;
if (cond == NULL)
return(EINVAL);
else if (cattr != NULL)
return(ENOSYS);
#ifdef MTHREAD_STRICT
else if (mthread_cond_valid(cond))
/* Already initialized */
return(EBUSY);
#endif
else if ((c = malloc(sizeof(struct __mthread_cond))) == NULL)
return(ENOMEM);
c->mc_mutex = NULL;
*cond = (mthread_cond_t) c;
mthread_cond_add(cond);
return(0);
}
/*===========================================================================*
* mthread_cond_remove *
*===========================================================================*/
#ifdef MTHREAD_STRICT
static void mthread_cond_remove(c)
mthread_cond_t *c;
{
/* Remove condition from list of valid, initialized conditions */
if ((*c)->mc_prev == NULL)
vc_front = (*c)->mc_next;
else
(*c)->mc_prev->mc_next = (*c)->mc_next;
if ((*c)->mc_next == NULL)
vc_rear = (*c)->mc_prev;
else
(*c)->mc_next->mc_prev = (*c)->mc_prev;
}
#endif
/*===========================================================================*
* mthread_cond_signal *
*===========================================================================*/
int mthread_cond_signal(cond)
mthread_cond_t *cond;
{
/* Signal a thread that condition 'cond' was met. Just a single thread. */
mthread_thread_t t;
mthread_tcb_t *tcb;
if (cond == NULL)
return(EINVAL);
else if (!mthread_cond_valid(cond))
return(EINVAL);
tcb = mthread_find_tcb(MAIN_THREAD);
if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
mthread_unsuspend(MAIN_THREAD);
for (t = (mthread_thread_t) 0; t < no_threads; t++) {
tcb = mthread_find_tcb(t);
if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond){
mthread_unsuspend(t);
break;
}
}
return(0);
}
/*===========================================================================*
* mthread_cond_valid *
*===========================================================================*/
#ifdef MTHREAD_STRICT
static int mthread_cond_valid(c)
mthread_cond_t *c;
{
/* Check to see if cond is on the list of valid conditions */
struct __mthread_cond *loopitem;
loopitem = vc_front;
while (loopitem != NULL) {
if (loopitem == *c)
return(1);
loopitem = loopitem->mc_next;
}
return(0);
}
#endif
/*===========================================================================*
* mthread_cond_verify *
*===========================================================================*/
#ifdef MDEBUG
int mthread_cond_verify(void)
{
/* Return true in case no condition variables are in use. */
return(vc_front == NULL);
}
#endif
/*===========================================================================*
* mthread_cond_wait *
*===========================================================================*/
int mthread_cond_wait(cond, mutex)
mthread_cond_t *cond;
mthread_mutex_t *mutex;
{
/* Wait for a condition to be signaled */
mthread_tcb_t *tcb;
struct __mthread_cond *c;
struct __mthread_mutex *m;
if (cond == NULL || mutex == NULL)
return(EINVAL);
c = (struct __mthread_cond *) *cond;
m = (struct __mthread_mutex *) *mutex;
if (!mthread_cond_valid(cond) || !mthread_mutex_valid(mutex))
return(EINVAL);
c->mc_mutex = m; /* Remember we're using this mutex in a cond_wait */
if (mthread_mutex_unlock(mutex) != 0) /* Fails when we're not the owner */
return(-1);
tcb = mthread_find_tcb(current_thread);
tcb->m_cond = c; /* Register condition variable. */
mthread_suspend(MS_CONDITION);
/* When execution returns here, the condition was met. Lock mutex again. */
c->mc_mutex = NULL; /* Forget about this mutex */
tcb->m_cond = NULL; /* ... and condition var */
if (mthread_mutex_lock(mutex) != 0)
return(-1);
return(0);
}
/* pthread compatibility layer. */
__weak_alias(pthread_cond_init, mthread_cond_init)
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