int checkForDeadlock(int N,int M)
{
acquireMutexLock(MATRIX_MUTEX);
int matrix[N][M];
FILE *fp = fopen(MATRIX_FILENAME, "r+");
int i,j;
for(i=0;i< N ;i++)
{
for(j=0;j< M ;j++)
{
fscanf(fp, "%d", &matrix[i][j]);
}
}
fclose(fp);
releaseMutexLock(MATRIX_MUTEX);
int pos[N];
for(i=0;i<N;i++)pos[i]=-1;
int flag=-1;
printf("\nChecking for Deadlock...\n\n");
j=0;
int k=0;
int found=0;
while(k<N && !found)
{
if(flag==-1)j=0;
for(i=0;i<N;i++)
if(matrix[i][j]==2) {pos[k]=i; break;}
if(pos[k]==-1) return 0;
if(pos[k]==pos[0] && k!=0) {found=1; break;}
flag=-1;
for(j=0;j<M;j++)
if(matrix[pos[k]][j]==1) {flag=j; break;}
if(flag==-1) return 0;
k++;
}
if(found)
{
printf("\n\nDeadlock !!!\n\nDeadlocked Cycle : \n");
//printf("k = %d\n",k );
for(i=0;i<k;i++)
printf("Train %d from %s is waiting for Train %d from %s\n",pid_arr[pos[i]], direction_arr[pos[i]] ,pid_arr[pos[i+1]] , direction_arr[pos[i+1]] );
printf("\n\nPress a key to kill all Processes and exit !\n");
getch();
killAllProcesses();
//appendResults(probability);
return 1;
}
else return 0;
}
int checkInternalCommand(char *args[]){
if (!strcmp(args[0],"clear")) { // "clear" command
pid_t pid;
int status;
if((pid = fork())==0)
execl("/usr/bin/clear", "clear", NULL);
else
waitpid(pid, &status, 0);
//continue;
return 1;
}
if (!strcmp(args[0],"exit")){ // "quit" command
killAllProcesses();
return -1;
}
if (!strcmp(args[0],"ps_all")){ // list
listAllProcesses();
return 1;
}
if (!strcmp(args[0],"kill")){ // kill
int index = 0;
char Index[10];
if(args[1][0] == '%')//INDEX
strcpy(Index, &args[1][1]);
else
strcpy(Index, &args[1][0]);
index = atoi(Index);
if(args[1][0] == '%')
killWithIndex(index);
else
killWithProcessId(index);
return 1;
}
if (!strcmp(args[0],"fg")){ // fg
int index = 0;
char Index[10];
if( args[1][0] != '%'){//INDEX
fprintf(stderr, "\nUsage : fg %cindex",'%');
return 1;
}
strcpy(Index, &args[1][1]);
index = atoi(Index);
bringForeground(index);
return 1;
}
if (!strcmp(args[0],"bg")){ // bg
bringBackground();
return 1;
}
return 0;
}
void main(int argc,char* argv[])
{
int DPP;
float probability = 0.2;
if(argc!=3)
{
printf("Please run the program with 2 arguments : <DPP_toggle (0 or 1)> <probability> \n"); // DPP --> Deadlock Prevention Protocol
exit(1);
}
else
{
sscanf(argv[1],"%d",&DPP);
sscanf(argv[2],"%f",&probability);
if((DPP != 0 && DPP != 1)||(probability<0 || probability >1))
{
printf("Please run the program with valid arguments : <DPP_toggle (0 or 1)> <probability>\n"); // DPP --> Deadlock Prevention Protocol
exit(1);
}
}
semID = semget((key_t)SEMAPHORE_KEY,7,IPC_CREAT|0666);
initializeAllSubSemaphoreValues();
acquireMutexLock(MATRIX_MUTEX);
initializeMatrixFile();
releaseMutexLock(MATRIX_MUTEX);
int mssgQ0_ID=msgget((key_t)MSSG_Q0_KEY,IPC_CREAT|0666);
int mssgQ1_ID=msgget((key_t)MSSG_Q1_KEY,IPC_CREAT|0666);
int i;
for(i=0;i<NUM_PRODUCERS;i++)
{
char command[50];
sprintf(command,"xterm -hold -e ./producer %d %d %d &",MSSG_Q0_KEY,MSSG_Q1_KEY,i);
system(command);
sleep(1); // otherwise the item to be first inserted becomes the same for all the Queues due to the timeseeding : srand(time(NULL))
}
for(i=0;i<NUM_CONSUMERS;i++)
{
char command[50];
sprintf(command,"xterm -hold -e ./consumer %d %d %d %f %d &",MSSG_Q0_KEY,MSSG_Q1_KEY,NUM_PRODUCERS+i,probability,DPP);
system(command);
}
while(1)
{
int m,n; // if Deadlock is found, then Consumer m (Cm) and Consumer n (Cn) are such that Q0 --> Cm --> Q1 --> Cn --> Q0, in the Resource Allocation Graph
int found_deadlock = 0;
printf("Checking for Deadlock...\n");
acquireMutexLock(MATRIX_MUTEX);
found_deadlock = checkForDeadlock(&m,&n);
releaseMutexLock(MATRIX_MUTEX);
if(found_deadlock)
{
printf("\n\nDeadlock !!!\n\nDeadlocked Cycle : Q0 --> C%d --> Q1 --> C%d --> Q0 \n\nKilling all Processes...",m,n);
printf("\n\nPress a key to kill all Processes\n");
getch();
killAllProcesses();
appendResults(probability);
exit(0);
}
sleep(2);
}
}
