#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>

#define COUNT 100
#define MAX_PROCS 1024

char wbuf[4096];

void run_test(char *base, int count)
{
	char pbuf[1024];
	int fd, i, j;

	sprintf(pbuf, "%s/file-%d", base, count);
	fd = open(pbuf, O_CREAT | O_TRUNC | O_WRONLY, 0644);
	if (fd < 0) {
		perror("open");
		exit(1);
	}
	
	for (i = 0; i < COUNT; i++) {
		if (pwrite(fd, wbuf, 4096, 0) != 4096) {
			perror("pwrite");
			exit(1);
		}

		for (j = 4095; j >= 1; j--) {
			if (ftruncate(fd, j) < 0) {
				perror("ftruncate");
				exit(1);
			}
		}
	}
}

int main(int argc, char **argv)
{
	int procs, i, j;
	pid_t pids[MAX_PROCS];

	if (argc != 3) {
		fprintf(stderr, "Usage: stress-orphan <processes> <dir>\n");
		return 1;
	}
	procs = strtol(argv[1], NULL, 10);
	if (procs > MAX_PROCS) {
		fprintf(stderr, "Too many processes!\n");
		return 1;
	}

	for (i = 0; i < procs; i++) {
		pids[i] = fork();
		if (pids[i] < 0) {
			perror("fork");
			for (j = 0; j < i; j++)
				kill(pids[j], SIGKILL);
			return 1;
		}
		if (pids[i] == 0) {
			run_test(argv[2], i);
			exit(0);
		}
	}

	printf("Processes started.\n");
	for (i = 0; i < procs; i++)
		waitpid(pids[i], NULL, 0);
	return 0;
}