#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// When compiled into a .cgi executable, this runs any query as a command
// on the server, allowing you to download remotely and divide the file into
// segments.
// The default command.cgi outputs nothing but the executable's stdout.
// The keepalive command2.cgi outputs something to keep the connection alive.
// Assume it's being invoked from the command line, not a browser.

int main(int argc, char *argv[])
{
// Debugging only
//	printf("Content-type:text/html\n\n");
//	printf("Content-type:application/octet-stream\n\n");

	int i;
	char *query = getenv("QUERY_STRING");
	char *the_command = argv[0];


#define SILENT_COMMAND "command.cgi"
#define KEEPALIVE_COMMAND "command2.cgi"
	int is_keepalive = (int)(strstr(the_command, KEEPALIVE_COMMAND));



	if(query && strlen(query))
	{
		char *query2 = strdup(query);
		char *ptr = strchr(query, '%');
		char *ptr2 = query;
		char *ptr3 = query2;
		unsigned char character;


// Convert % codes to characters
		while(ptr)
		{
// Copy leading good text
			while(ptr2 < ptr)
				*ptr3++ = *ptr2++;

// Convert hex to character
			ptr++;
			character = ' ';
			if(*ptr)
			{
				if(isdigit(*ptr)) 
					character = (*ptr - '0') * 0x10;
				else
					character = (tolower(*ptr) - 'a' + 10) * 0x10;
				ptr++;
				if(*ptr)
				{
					if(isdigit(*ptr)) 
						character += (*ptr - '0');
					else
						character += (tolower(*ptr) - 'a' + 10);
					ptr++;
				}
			}
			*ptr3++ = character;
			ptr2 = ptr;
			ptr = strchr(ptr, '%');
		}
		while(*ptr2)
			*ptr3++ = *ptr2++;
		*ptr3++ = 0;

//		printf("query = %s\n", query2);
//		printf("result = ");
//		fflush(stdout);

		FILE *file = popen(query2, "r");


		if(is_keepalive)
		{
			printf("Content-type:text/html\n\n");
			printf("Keepalive mode.\n");
			while(!feof(file))
			{
				fd_set fds;
				struct timeval tv;
				int result;

				FD_ZERO(&fds);
				FD_SET(fileno(file), &fds);
				tv.tv_sec = 1;
				tv.tv_usec = 0;

				result = select(fileno(file) + 1, &fds, 0, 0, &tv);

// Timed out
				if(!result)
				{
					printf(".\n");
					fflush(stdout);
				}
				else
				if(result == -1)
				{
// Done
					break;
				}
				else
				{
					character = fgetc(file);
				}
			}
		}
		else
		{
			printf("Content-type:application/octet-stream\n\n");

			while(!feof(file))
			{
				character = fgetc(file);
				if(feof(file)) break;
				fputc(character, stdout);
			}
		}



		pclose(file);
		if(is_keepalive)
		{
// Client closes as soon as it gets Done. so must wait for pclose
			printf("D");
			fflush(stdout);
		}
		free(query2);
	}
	else
	{
		printf("Content-type:text/html\n\n");
		printf("No query received you MOR*ON!\n");
	}
	fflush(stdout);

	return 0;
}