#include <stdio.h>
#include <sys/types.h>
#include <sys/times.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>

#define U1 12 /* Gets 1 process */
#define U2 13 /* Gets 3 processes */
#define U3 14 /* Gets 6 processes */
#define U4 15 /* Gets a low priority process */

long count;
FILE *outfile;

void kill(int pid, int signum);

void sig_handler(int signum) {
	/* If we get this signal, we need to write count to file and exit */
	fprintf(outfile, "%d\n%d\n ",getpid(),count);
	fflush(outfile);
	exit(count);
}	

int main(int argc, char *argv[]) {
	int status;	
	int i, j, k, cpid;
	int pids[11];
	int pid_counts[11];
	double percent;
	long total;
	
	printf("Welcome to the test program for the Fair-Share Scheduler\n");
	printf("Forking and running children...\n");
	
	signal(SIGQUIT, sig_handler);
	
	outfile = fopen("stats", "w");
	if (outfile == NULL) {
		printf("Failed to open stats file!\n");
		return 1;
	}
	
	cpid = fork();
	if (cpid == 0){
		/* Parent */
		/* Set to be U1 */
		status = setuid(U1);
		if(status) printf("Failed to set UID to %d\n",U1);
		
		/* Now start an infinite loop */
		printf("PID %d starting under user %d\n",getpid(), U1);
		count = 0;
		while(1){
			for(i=0;i<1000000;i++);
			count++;
		}
	}
	else {
		/* PID of first child */
		pids[0] = cpid;
		/* Child */
		for (i = 0; i < 3; i++) {
			cpid = fork();
			if (cpid == 0) {
				status = setuid(U2);
				if(status) printf("Failed to set UID to %d\n",U2);
				printf("PID %d starting under user %d\n",getpid(),U2);
				count = 0;
				while(1){
					for(i=0;i<1000000;i++);
					count++;
				}
			}
			else {
				pids[i+1] = cpid;
			}
		}
		for (i = 0; i < 6; i++) {
			cpid = fork();
			if (cpid == 0) {
				status = setuid(U3);
				if(status) printf("Failed to set UID to %d\n",U3);
				printf("PID %d starting under user %d\n",getpid(), U3);
				count = 0;
				while(1){
					for(i=0;i<1000000;i++);
					count++;
				}
			}
			else {
				pids[i+4] = cpid;
			}
		}

	}	

	/* Fork off a low priority process */
	cpid = fork();
	if (cpid == 0) {
		status = setuid(U4);
		printf("PID %d starting low priority under user %d\n",getpid(), U4);
		setpriority(PRIO_PROCESS, getpid(), 20);
		count = 0;
		while(1){
			for(i=0;i<1000000;i++);
			count++;
		}
	}
	else {
		pids[10] = cpid;
		sleep(60);	
		printf("Reaping children!\n");
		/* Do a loop to kill all processes as close together as possible */ 
		for(i=0;i<11;i++){
			/* printf("Signalling PID %d\n",pids[i]); */
			kill(pids[i], SIGQUIT);
		}
		/* And another loop to synchronize */
		for(i=0;i<11;i++){
			wait(&pids[i]);
		}
		printf("They're all dead now here's some stats about their lives:\n");
		fclose(outfile);
		/* Re-open the file for reading now */
		fopen("stats", "r");
		
		/* Process the data nicely (sort of!) */
		total = 0;
		for(i=0;i<11;i++){
			status = fscanf(outfile, "%d\n",&pids[i]);
			status = fscanf(outfile, "%d\n",&pid_counts[i]);
		/*	printf("Read: %d %d from file\n",pids[i], pid_counts[i]);*/
			total += pid_counts[i];
		}
		printf("Total count: %d\n",total);
		printf("Results should be: 1x33%%, 3x11%%, 6x5.5%%, 1x1%%\n");
		for(i=0;i<11;i++){
			percent = (((double)pid_counts[i]/total)*100);
			printf("PID %d: %d = %f%% share\n",pids[i],pid_counts[i], percent);
		}
						
	}	
	return 0;
}