#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <signal.h>
#include <ctype.h>
#include <sched.h>

#define __USE_GNU
#include <sys/ipc.h>

#ifdef SDR_TOOLS
#include <dump_log.h>
#include <linux/logdev.h>
#include <dump_log.h>
#include <tracer_xml.h>
#include "dump_trace.h"
int logfd = -1;
#else
#define logdev_print(x...) do {} while(0)
#define logdev_switch_set(x) (0)
#endif

#include <list.h>


static int reader (int i);

typedef int (*callfunc_t)(int);

#define NR_PROCS 5
pid_t pids[NR_PROCS];
callfunc_t dofunc[NR_PROCS] = {
	reader,
	reader,
	reader,
	reader,
	reader
};

int priorities[NR_PROCS] = {
	10,
	11,
	12,
	13,
	14,
};

key_t key;
int semid = -1;
int shmid = -1;
int safe = 0;
int tod = 0;
int *flags;

void cleanup(void)
{
	int i;

	for (i=0; i < NR_PROCS; i++) {
		if (pids[i])
			kill(pids[i],SIGKILL);
	}

	if (semid >= 0)
		semctl(semid, 0, IPC_RMID);
	if (shmid >= 0)
		shmctl(shmid, IPC_RMID, NULL);
#ifdef SDR_TOOLS
	if (logfd >= 0)
		close_logdev(logfd);
#endif
}

void catchall(int sig)
{
	cleanup();
	psignal(sig,"Caught: ");
	exit(-1);
}

static int compare_timeval(const struct timeval *a, const struct timeval *b)
{
	return (a->tv_sec > b->tv_sec) ? 1 :
		(a->tv_sec < b->tv_sec) ? -1:
		(a->tv_usec > b->tv_usec) ? 1:
		(a->tv_usec < b->tv_usec) ? -1:
		0;
}

static void add_timeval(const struct timeval *a, const struct timeval *b, struct timeval *c)
{

	c->tv_usec = a->tv_usec + b->tv_usec;
	c->tv_sec = a->tv_sec + b->tv_sec;
	while (c->tv_usec > 1000000) {
		c->tv_usec -= 1000000;
		c->tv_sec++;
	}

}

static void sub_timeval(const struct timeval *a, const struct timeval *b, struct timeval *c)
{

	c->tv_usec = a->tv_usec - b->tv_usec;
	c->tv_sec = a->tv_sec - b->tv_sec;
	while (c->tv_usec < 0) {
		c->tv_usec += 1000000;
		c->tv_sec--;
	}

}

struct dir_item {
	struct list_head list;
	char *dir;
};

LIST_HEAD_DECLARE(dirs);

static void read_dirs(char *dirname)
{
	DIR *dir;
	struct dirent *dent;
	struct stat st;
	struct dir_item *item;
	int len = strlen(dirname);
	char *name;
	
	if ((dir = opendir(dirname)) == NULL)
		return;

	while ((dent = readdir(dir))) {
		if (strcmp(dent->d_name,".") == 0 ||
		    strcmp(dent->d_name,"..") == 0)
			continue;

		
		name = malloc(strlen(dent->d_name)+len+2);
		if (!name) {
			goto out;
		}

		strcpy(name,dirname);
		name[len] = '/';
		strcpy(name+len+1,dent->d_name);

		if (stat(name,&st) < 0) {
			perror(name);
			free(name);
			continue;
		}

		if ((S_ISDIR(st.st_mode))) {
			item = malloc(sizeof(*item));
			if (!item) {
				free(name);
				goto out;
			}
			item->dir = name;
			
			list_add_tail(&item->list,&dirs);
		} else {
			free(name);
		}
	}
 out:
	closedir(dir);
}
			

static int reader(int i)
{
	struct sembuf sops;
	int semid;
	struct timeval starttv;
	struct timeval endtv;
	struct timeval tv;
	struct timeval lasttv;
	struct timeval deltatv;
	time_t t;
	char timebuf[30];
	unsigned long long starttsc, nowtsc;

	memset(&sops,0,sizeof(sops));
	
	if ((semid = semget(key,1,0)) < 0) {
		perror("semget");
		return -1;
	}

	printf("reader %d grabbing waiting on sem\n",i);
	if (semop(semid, &sops, 1) < 0) {
		perror("semop");
		return -1;
	}

	logdev_print(logfd,"reader %d past semaphore\n",i);

	if (gettimeofday(&starttv,NULL) < 0) {
		perror("gettimeofday");
		return -1;
	}

	memset (&deltatv,0,sizeof(deltatv));

	endtv.tv_sec = 10;
	endtv.tv_usec = 0;

	add_timeval(&starttv,&endtv,&endtv);

	t = time(NULL);
	ctime_r(&t,timebuf);
	timebuf[strlen(timebuf)-1] = 0;

	printf("reader %d starting loop (%s)\n",i,timebuf);
	logdev_print(logfd,"reader %d (pid %d) starting loop (%s)\n",i,getpid(),timebuf);
	lasttv = starttv;
	asm ("rdtsc" : "=A"(starttsc));
	
	chdir("/");
	read_dirs("/");
	
	do {
		struct list_head *p;
		struct dir_item *item;

		asm ("rdtsc" : "=A"(nowtsc));
		if (safe && (nowtsc - starttsc > 8000000000ULL)) {
			printf("now - start > 8000000000\n");
			break;
		}
		
		
		if (list_empty(&dirs))
			break;

		p = dirs.next;
		list_del(p);
		item = list_entry(p,struct dir_item, list);
		read_dirs(item->dir);
		free(item->dir);
		free(item);
		
		if (gettimeofday(&tv,NULL) < 0) {
			perror("gettimeofday (in loop)");
			return -1;
		}

		sub_timeval(&tv,&lasttv,&lasttv);
		if (compare_timeval(&deltatv,&lasttv) < 0)
			deltatv = lasttv;
		lasttv = tv;
	} while(!tod || compare_timeval(&endtv,&tv) > 0);
	t = time(NULL);
	ctime_r(&t,timebuf);
	timebuf[strlen(timebuf)-1] = 0;
	logdev_print(logfd,"spinner %d (pid %d) done (%s)\n",i,getpid(),timebuf);
	printf("spinner %d ended loop (%s)  (%d.%06d secs delta)\n",
	       i,timebuf,(int)deltatv.tv_sec,(int)deltatv.tv_usec);
	

	return 0;
}


void usage(char **argv)
{
	char *arg = argv[0];
	char *p = arg+strlen(arg);

	while (p >= arg && *p != '/') p--;
	p++;

	printf("\nusage: %s [-st]\n"
	       "  -s : safe mode. Have the readers use the tsc to stop\n"
	       "  -t : use timeofday to stop loop\n"
	       "\n",p);
	exit(-1);
}

int main (int argc, char **argv)
{
	int ret=0;
	int i;
	int nr_procs=0;
	struct sembuf sops;
	int c;

	opterr = 0;
	while ((c=getopt(argc,argv,"hnsf:")) >= 0) {
		switch (c) {
		case 's':
			safe = 1;
			break;
		case 't':
			tod = 1;
			break;
		case 'h':
		default:
			printf("\n");
			if (c != ':' && tolower(optopt) != 'h' && optopt != '?')
				printf("unknown option: %c\n",optopt);
			usage(argv);
		}
	}

	key = ftok(argv[0],123);
	
	if ((semid = semget(key,1,IPC_CREAT|IPC_EXCL|0600)) < 0) {
		perror("semget");
		exit (-1);
	}

	if ((shmid = shmget(key,30,IPC_CREAT|IPC_EXCL|0600)) < 0) {
		perror("shmget");
		goto out;
	}
	
	if ((flags = shmat(shmid, NULL, 0)) == (void*)-1) {
		perror("shmat");
		goto out;
	}

#ifdef SDR_TOOLS
	if ((logfd = open_logdev(NULL,O_RDWR)) < 0) {
		perror("open_logdev");
		goto out;
	}

	if (logdev_switch_set(1)) {
		perror("logdev_switch_on");
	}
#endif


	/* Grab the semaphore before anyone else can take it. */
	memset(&sops,0,sizeof(sops));
//	sops.sem_flg = SEM_UNDO;
	sops.sem_op = 1;
	if (semop(semid, &sops, 1) < 0) {
		perror("semop");
		ret = -1;
		goto out;
	}

	for (i=0; i < NR_PROCS; i++) {
		struct sched_param p;

		if ((pids[i] = fork()) < 0) {
			perror("fork");
			ret = -1;
			goto out;
		} else if (pids[i] == 0) {
			/* child */
			ret = dofunc[i](i);
			exit(ret);
		}
		nr_procs++;

		p.sched_priority = priorities[i];
		if (sched_setscheduler(pids[i],SCHED_FIFO,&p)) {
			perror("sched_setscheduler");
			goto out;
		}

		
		/* parent */
	}

	
	signal(SIGINT,catchall);
	signal(SIGILL,catchall);
	signal(SIGFPE,catchall);
	signal(SIGSEGV,catchall);
	signal(SIGBUS,catchall);

	sleep(1);
	printf("parent zeroing semaphore\n");

	sops.sem_op = -1;
	
	if (semop(semid,&sops,1) < 0) {
		perror("semop");
		ret = -1;
		goto out;
	}

	while (nr_procs) {
		int status;
		pid_t pid;
		if ((pid = wait(&status)) < 0) {
			perror("wait");
			break;
		}
		for (i=0; i < NR_PROCS; i++) {
			if (pids[i] == pid) {
				pids[i] = 0;
				nr_procs--;
			}
		}
		
	}

	if (logdev_switch_set(0)) {
		perror("logdev_switch_off");
	}

 out:
	cleanup();
	exit(ret);
}