Engineering school, 3rd year
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/************************************************************************/
/* EX11.C INTERBLOCAGE alias ETREINTE FATALE alias DEAD LOCK */
/************************************************************************/
/* Fonction : */
/* Deux tâches de même priorité travaillent en partage du temps. */
/* Ces deux tâches utilisent DEUX ressources communes. */
/* Si l'on ne prend pas de précaution, ce qui est le cas dans cet */
/* exercice : CA BLOQUE !!! */
/************************************************************************/
#include <basec.h>
#include <str.h>
#include <video.h>
/* #include <stdlib.h> */
#define T1 1
#define T2 2
#define TK 3
#define PT1 1
#define PT2 1
#define PTK 3
#define Ress1 1
#define Ress2 2
#define DELAY 5
#define ESC 0x1b
Word F0,F1,F2,F3;
#include "tempo.c"
/*-------------------------------------------------------------------*/
TKill(void)
{
Char Msg1;
while(1)
{
LireCar(F1,ON,&Msg1);
if( Msg1 == ESC ) RetDos();
}
}
/*-------------------------------------------------------------------*/
/* La fonction random n'existe pas, nous l'avons recodee */
int random(int max) {
return rand() % max;
}
Tache1(void)
{
Int cmpt = 0;
while(1)
{
while (1)
{
P(Ress1,0);
EcrTexte(F1,"Ress1\r");
Tempo(1);
/* Si la ressource est disponible on la prend et on sort de la boucle */
if (!TestP(Ress2)) break;
/* Sinon, on relache la ressource et on attend un delai aleatoire */
V(Ress1);
EffaceFen(F1);
DelayTask(random(DELAY) + 1);
}
++cmpt;
EcrTexte(F1,"Ress2\r\n");
SelectFen(F1);
EcrVar("%d execution(s)\r\n",cmpt);
Tempo(5);
EffaceFen(F1);
/* Liberation des ressources */
V(Ress2);
V(Ress1);
}
}
/*-------------------------------------------------------------------*/
Tache2(void)
{
Int cmpt = 0;
while(1)
{
while (1)
{
P(Ress2,0);
EcrTexte(F2,"Ress2\r");
Tempo(1);
if (!TestP(Ress1)) break;
V(Ress2);
EffaceFen(F2);
DelayTask(random(DELAY) + 1);
}
++cmpt;
EcrTexte(F2,"Ress1\r\n");
SelectFen(F2);
EcrVar("%d execution(s)\r\n",cmpt);
Tempo(5);
EffaceFen(F2);
V(Ress1);
V(Ress2);
}
}
/*-------------------------------------------------------------------*/
void main(void)
{
InitVideo();
F0 = OuvreFen( 0, 0,79,24, noir, blanc, "EX 11 : INTERBLOCAGE alias ETREINTE FATALE alias DEAD LOCK");
F1 = OuvreFen( 5, 5,30,15, bleu, blanc, "T1 En Cours");
F2 = OuvreFen(40, 5,65,15, vert, blanc, "T2 En Cours");
F3 = OuvreFen( 2,20,77,23, cyan, blanc, "TACHE MAIN");
InitNoyau();
CreateTask(T1, PT1, Tache1);
CreateTask(T2, PT2, Tache2);
CreateTask(TK, PTK, TKill);
InitSemaphore(Ress1, 1); V(Ress1);
InitSemaphore(Ress2, 1); V(Ress2);
EnterRegion();
StartTask(T2);
StartTask(T1);
StartTask(TK);
RTClockInit(1);
LeaveRegion();
while(1)
{
EnterRegion();
EcrCar(F3,'&');
LeaveRegion();
Tempo(2);
}
}