/******************************************************************
 * Created: Josep Valls 20080211
 * Process monitor for CMPS105/Winter2008
 * Practice the use of the /proc file system
 * Features: lists process, refreshes automatically
 * Wishlist: order by cpu usage, memory size, user..., 
 ******************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <signal.h>
#include <dirent.h>
#include <asm/page.h>
#include <math.h>


typedef struct{
	pid_t pid;
	char comm[255];
	char state;
	long size;
	long cpu;
	long cpup;
	uid_t uid;
} s_jobs;

void printEnvironmentInformation();
void printGeneralInformation();
void print_time(char* label, long time);

int sortJobsCmp (const struct s_jobs *c1, const struct s_jobs *c2){
  //return strcmp(&c1->comm, &c2->comm);
  //if(&c1->size>&c2->size) return 1; return 0;
  return (int)(random()*2);
  //return -1;
}

int main(int argc, char *argv[])
{
	DIR *cdir;
	struct dirent *cdirc;

	FILE *fp;
	char *dirname=(char *) malloc(255*sizeof(char));
	int procid;
	char *procname[255];
	
	struct stat st;

	s_jobs jobs[1000];
	
	int i;

	int itmp;
	char ctmp;
	long ltmp,ttmp;

	//print some general information, maybe optional commandline
	printEnvironmentInformation();	
	printGeneralInformation();

	//main loop
	//traverse the /proc file system	
do{
	procid=0;
	ttmp=0;
	if(cdir=opendir("/proc/")){
		while(cdirc=readdir(cdir)){
			if (strcmp(cdirc->d_name, ".")  == 0) continue;
			if (strcmp(cdirc->d_name, "..") == 0) continue;
			if (cdirc->d_type==DT_DIR){
				if (strspn(cdirc->d_name, "0123456789") == strlen(cdirc->d_name)){
					//check if it is only numeric, more likely to be a process
					strcpy(dirname,"/proc/");
					strcat(dirname,cdirc->d_name);
					strcat(dirname,"/stat");

					//printf("%s\n",dirname);
					if(fp=fopen((char *)dirname, "r")){
						fstat(fp,&st);
						jobs[procid].uid=st.st_uid;
						fscanf(fp,"%d %s %c", &jobs[procid].pid, &jobs[procid].comm,&jobs[procid].state);
						//skip all the fields that we don't need
						fscanf(fp,"%d",&itmp);
						fscanf(fp,"%d",&itmp);
						fscanf(fp,"%d",&itmp);
						fscanf(fp,"%d",&itmp);
						fscanf(fp,"%d",&itmp);
						fscanf(fp,"%lu",&ltmp);
						fscanf(fp,"%lu",&ltmp);
						fscanf(fp,"%lu",&ltmp);
						fscanf(fp,"%lu",&ltmp);
						fscanf(fp,"%lu",&ltmp);
						//get the old cpu jiffles
						ltmp=jobs[procid].cpu;
						fscanf(fp,"%lu",&jobs[procid].cpu);
						jobs[procid].cpup=jobs[procid].cpu-ltmp;
						ttmp+=jobs[procid].cpup;
						printf("%d %d\n",ttmp,jobs[procid].cpup);
						fscanf(fp,"%lu",&ltmp);
						fscanf(fp,"%ld",&ltmp);
						fscanf(fp,"%ld",&ltmp);
						fscanf(fp,"%ld",&ltmp);
						fscanf(fp,"%ld",&ltmp);
						fscanf(fp,"%ld",&ltmp);
						fscanf(fp,"%ld",&ltmp);
						fscanf(fp,"%lu",&ltmp);
						fscanf(fp,"%lu", &jobs[procid].size);						
						fclose(fp);
						//printf("%s %c %d\n",jobs[procid].comm,jobs[procid].state,jobs[procid].size);
						procid++;
					}
				}
			}
		}
		closedir(cdir);
		//update cpu usage
		for (i = 0; i < procid-1; i++){
			jobs[i].cpup=jobs[i].cpup*100/ttmp;
		}
		
		/*
		printf("PID\t STAT\t CPU%%\t SIZE\t COMMAND\n");
		for (i = 0; i < procid-1; i++)
			printf("%d\t %c\t %d\t %d\t %s\n",jobs[i].pid, jobs[i].state, jobs[i].cpup, jobs[i].size, jobs[i].comm);
			
		printf("-------------------------------------------\n");
		*/
		qsort (jobs, procid-1, sizeof(s_jobs), sortJobsCmp);
		//Print the information
		printf("PID\t STAT\t CPU%%\t SIZE\t USER\t COMMAND\n");
		for (i = 0; i < procid-1&&i<20; i++)
			printf("%d\t %c\t %d\t %dk\t %d %s\n",jobs[i].pid, jobs[i].state, jobs[i].cpup, (int)jobs[i].size/1024, jobs[i].uid, jobs[i].comm);

	}else{
		printf("Error opening directory /proc.  Errno = %d.\n",errno);
		printf(" %s.\n", strerror(errno));
	}
	printf("control+c to quit\n");
	//time refresh routine... not very accurate i fear...
	struct timeval tv;
	int retval, milisec;
	milisec=3000;
	tv.tv_sec = (milisec - (milisec % 1000)) / 1000;
	tv.tv_usec = (milisec - (tv.tv_sec * 1000)) * 1000; 
	retval = select(0, NULL, NULL, NULL, &tv);
	if(retval == -1)
		perror("select()");
	else
		printf("Slept for %d milliseconds,refreshing\n", milisec);

}while(1);
}
void printEnvironmentInformation(){
	int i;
	char **ptr;
	extern char **environ;
	
	for(ptr=environ; *ptr!=0; ptr++){
		printf("%s\n",*ptr);
	}
}
void printGeneralInformation(){
	FILE* fp;
	double uptime, idle_time;
	/* Read the system uptime and accumulated idle time from /proc/uptime. */
	fp = fopen ("/proc/uptime", "r");
	fscanf (fp, "%lf %lf\n", &uptime, &idle_time);
	fclose (fp);

	print_time ("uptime ", (long) uptime);
	print_time ("idle time ", (long) idle_time);
}
void print_time(char* label, long time){
	const long minute = 60;
	const long hour = minute * 60;
	const long day = hour * 24;
	printf ("%s: %ld days, %ld:%02ld:%02ld\n",label, time / day, (time % day) / hour, (time % hour) / minute, time % minute);
}