76092ddf33
This can be turned back on when the library is compiled with -DMTHREAD_STRICT (which enables more sanity checks). However, always performing this check shows up in system profiling results.
288 lines
7.5 KiB
C
288 lines
7.5 KiB
C
#include <minix/mthread.h>
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#include "global.h"
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#include "proto.h"
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#ifdef MTHREAD_STRICT
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static struct __mthread_cond *vc_front, *vc_rear;
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static void mthread_cond_add(mthread_cond_t *c);
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static void mthread_cond_remove(mthread_cond_t *c);
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static int mthread_cond_valid(mthread_cond_t *c);
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#else
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# define mthread_cond_add(c) ((*c)->mc_magic = MTHREAD_INIT_MAGIC)
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# define mthread_cond_remove(c) ((*c)->mc_magic = MTHREAD_NOT_INUSE)
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# define mthread_cond_valid(c) ((*c)->mc_magic == MTHREAD_INIT_MAGIC)
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#endif
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#define MAIN_COND mainthread.m_cond
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/*===========================================================================*
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* mthread_init_valid_conditions *
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*===========================================================================*/
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void mthread_init_valid_conditions(void)
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{
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#ifdef MTHREAD_STRICT
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/* Initialize condition variable list */
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vc_front = vc_rear = NULL;
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#endif
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}
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/*===========================================================================*
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* mthread_cond_add *
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*===========================================================================*/
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#ifdef MTHREAD_STRICT
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static void mthread_cond_add(c)
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mthread_cond_t *c;
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{
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/* Add condition to list of valid, initialized conditions */
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if (vc_front == NULL) { /* Empty list */
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vc_front = *c;
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(*c)->mc_prev = NULL;
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} else {
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vc_rear->mc_next = *c;
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(*c)->mc_prev = vc_rear;
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}
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(*c)->mc_next = NULL;
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vc_rear = *c;
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}
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#endif
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/*===========================================================================*
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* mthread_cond_broadcast *
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*===========================================================================*/
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int mthread_cond_broadcast(cond)
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mthread_cond_t *cond;
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{
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/* Signal all threads waiting for condition 'cond'. */
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mthread_thread_t t;
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mthread_tcb_t *tcb;
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MTHREAD_CHECK_INIT(); /* Make sure libmthread is initialized */
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if (cond == NULL)
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return(EINVAL);
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else if (!mthread_cond_valid(cond))
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return(EINVAL);
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tcb = mthread_find_tcb(MAIN_THREAD);
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if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
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mthread_unsuspend(MAIN_THREAD);
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for (t = (mthread_thread_t) 0; t < no_threads; t++) {
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tcb = mthread_find_tcb(t);
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if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
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mthread_unsuspend(t);
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}
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return(0);
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}
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/*===========================================================================*
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* mthread_cond_destroy *
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*===========================================================================*/
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int mthread_cond_destroy(cond)
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mthread_cond_t *cond;
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{
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/* Destroy a condition variable. Make sure it's not in use */
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mthread_thread_t t;
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mthread_tcb_t *tcb;
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MTHREAD_CHECK_INIT(); /* Make sure libmthread is initialized */
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if (cond == NULL)
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return(EINVAL);
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else if (!mthread_cond_valid(cond))
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return(EINVAL);
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/* Is another thread currently using this condition variable? */
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tcb = mthread_find_tcb(MAIN_THREAD);
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if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
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return(EBUSY);
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for (t = (mthread_thread_t) 0; t < no_threads; t++) {
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tcb = mthread_find_tcb(t);
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if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
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return(EBUSY);
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}
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/* Not in use; invalidate it. */
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mthread_cond_remove(cond);
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free(*cond);
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*cond = NULL;
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return(0);
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}
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/*===========================================================================*
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* mthread_cond_init *
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*===========================================================================*/
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int mthread_cond_init(cond, cattr)
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mthread_cond_t *cond;
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mthread_condattr_t *cattr;
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{
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/* Initialize condition variable to a known state. cattr is ignored */
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struct __mthread_cond *c;
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MTHREAD_CHECK_INIT(); /* Make sure libmthread is initialized */
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if (cond == NULL)
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return(EINVAL);
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else if (cattr != NULL)
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return(ENOSYS);
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#ifdef MTHREAD_STRICT
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else if (mthread_cond_valid(cond))
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/* Already initialized */
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return(EBUSY);
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#endif
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else if ((c = malloc(sizeof(struct __mthread_cond))) == NULL)
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return(ENOMEM);
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c->mc_mutex = NULL;
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*cond = (mthread_cond_t) c;
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mthread_cond_add(cond);
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return(0);
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}
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/*===========================================================================*
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* mthread_cond_remove *
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*===========================================================================*/
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#ifdef MTHREAD_STRICT
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static void mthread_cond_remove(c)
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mthread_cond_t *c;
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{
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/* Remove condition from list of valid, initialized conditions */
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if ((*c)->mc_prev == NULL)
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vc_front = (*c)->mc_next;
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else
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(*c)->mc_prev->mc_next = (*c)->mc_next;
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if ((*c)->mc_next == NULL)
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vc_rear = (*c)->mc_prev;
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else
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(*c)->mc_next->mc_prev = (*c)->mc_prev;
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}
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#endif
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/*===========================================================================*
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* mthread_cond_signal *
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*===========================================================================*/
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int mthread_cond_signal(cond)
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mthread_cond_t *cond;
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{
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/* Signal a thread that condition 'cond' was met. Just a single thread. */
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mthread_thread_t t;
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mthread_tcb_t *tcb;
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MTHREAD_CHECK_INIT(); /* Make sure libmthread is initialized */
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if (cond == NULL)
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return(EINVAL);
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else if (!mthread_cond_valid(cond))
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return(EINVAL);
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tcb = mthread_find_tcb(MAIN_THREAD);
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if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond)
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mthread_unsuspend(MAIN_THREAD);
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for (t = (mthread_thread_t) 0; t < no_threads; t++) {
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tcb = mthread_find_tcb(t);
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if (tcb->m_state == MS_CONDITION && tcb->m_cond == *cond){
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mthread_unsuspend(t);
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break;
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}
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}
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return(0);
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}
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/*===========================================================================*
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* mthread_cond_valid *
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*===========================================================================*/
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#ifdef MTHREAD_STRICT
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static int mthread_cond_valid(c)
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mthread_cond_t *c;
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{
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/* Check to see if cond is on the list of valid conditions */
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struct __mthread_cond *loopitem;
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MTHREAD_CHECK_INIT();
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loopitem = vc_front;
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while (loopitem != NULL) {
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if (loopitem == *c)
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return(1);
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loopitem = loopitem->mc_next;
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}
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return(0);
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}
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#endif
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/*===========================================================================*
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* mthread_cond_verify *
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*===========================================================================*/
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#ifdef MDEBUG
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int mthread_cond_verify(void)
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{
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/* Return true in case no condition variables are in use. */
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MTHREAD_CHECK_INIT(); /* Make sure libmthread is initialized */
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return(vc_front == NULL);
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}
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#endif
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/*===========================================================================*
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* mthread_cond_wait *
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*===========================================================================*/
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int mthread_cond_wait(cond, mutex)
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mthread_cond_t *cond;
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mthread_mutex_t *mutex;
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{
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/* Wait for a condition to be signaled */
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mthread_tcb_t *tcb;
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struct __mthread_cond *c;
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struct __mthread_mutex *m;
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MTHREAD_CHECK_INIT(); /* Make sure libmthread is initialized */
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if (cond == NULL || mutex == NULL)
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return(EINVAL);
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c = (struct __mthread_cond *) *cond;
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m = (struct __mthread_mutex *) *mutex;
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if (!mthread_cond_valid(cond) || !mthread_mutex_valid(mutex))
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return(EINVAL);
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c->mc_mutex = m; /* Remember we're using this mutex in a cond_wait */
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if (mthread_mutex_unlock(mutex) != 0) /* Fails when we're not the owner */
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return(-1);
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tcb = mthread_find_tcb(current_thread);
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tcb->m_cond = c; /* Register condition variable. */
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mthread_suspend(MS_CONDITION);
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/* When execution returns here, the condition was met. Lock mutex again. */
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c->mc_mutex = NULL; /* Forget about this mutex */
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tcb->m_cond = NULL; /* ... and condition var */
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if (mthread_mutex_lock(mutex) != 0)
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return(-1);
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return(0);
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}
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