#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <io.h>
#include <process.h>
#include <string.h>
#include <memory.h>
#include <errno.h>
#include <fcntl.h>

#define SEARCH_STRING	"TUNNELESTABLISHED"

#define PIPE_BUFFER_SIZE	512


#define SSH_OPTIONS		" -o\"CheckHostIP no\""					\
						" -o\"StrictHostKeyChecking no\""		\
						" -o\"UserKnownHostsFile /dev/null\""

#define SSH_CMD			"ssh -L 5901:localhost:5900 "SSH_OPTIONS" "
#define SSH_CMD_APPEND	"\"echo "SEARCH_STRING";\nsleep 30\""


char *g_chkbuffer = NULL;
int g_szchkbuffer = 0;
int ProcessBuffer( char *pIn, int n ) {
	int i;
	for (i=0; i<n; i++) {
		/* Shift out old */
		memmove(g_chkbuffer, g_chkbuffer+1, g_szchkbuffer-1);

		g_chkbuffer[g_szchkbuffer-1] = pIn[i];

		/* Stop when we get the search string */
		if (!memcmp(g_chkbuffer, SEARCH_STRING, g_szchkbuffer)) {
			return 1;
		}
	}
	return 0;
}

int main( int argc, char **argv ) {
	char *cp_cmdline = NULL;
	char rd[PIPE_BUFFER_SIZE];
	int hpipe[2];
	int i;
	int rc;
	int oldstdout;
	PROCESS_INFORMATION pi;
	STARTUPINFO si;

	if (argc < 2) {
		fprintf(stderr,
"Usage: %s <SSH_ARGUMENTS>\n"
"\tOpen a SSH tunnel and spawn a local VNC viewer connected to it\n"
"\t<SSH_ARGUMENTS> are arguments to ssh, one of which must\n"
"\tspecify which host to connect to\n", argc>0?argv[0]:"svnc");
		return 1;
	}

	/* Generate the command line */
	cp_cmdline = strdup(SSH_CMD);
	for (i=1;i<argc; i++) {
		cp_cmdline = realloc(cp_cmdline, strlen(cp_cmdline)+strlen(argv[i])+2);
		if (!cp_cmdline) { perror("realloc"); return 1; }
		strcat(cp_cmdline, " ");
		strcat(cp_cmdline, argv[i]);
	}
	cp_cmdline = realloc(cp_cmdline, strlen(cp_cmdline)+strlen(SSH_CMD_APPEND)+2);
	if (!cp_cmdline) { perror("realloc"); return 1; }
	strcat(cp_cmdline, " ");
	strcat(cp_cmdline, SSH_CMD_APPEND);

	/* Set up a pipe so we can do redirection */
	if (_pipe( hpipe, PIPE_BUFFER_SIZE, O_BINARY ) != 0) {
		fprintf(stderr, "Error creating pipe: %s\n", strerror(errno));
		return 1;
	}
	/* But save the current stdout for later */
	if ((oldstdout = _dup( _fileno(stdout) )) == -1) {
		fprintf(stderr, "Unable to save old stdout: %s\n", strerror(errno));
		return 1;
	}
	/* Redirect our (and thus our children's) stdout */
	if (_dup2( hpipe[1], _fileno(stdout) ) != 0) {
		fprintf(stderr, "Error redirecting stdout: %s\n", strerror(errno));
		return 1;
	}
	/* Don't need this name for the pipe anymore, close it */
	close(hpipe[1]);

	/* Get our startup info (run the child in our terminal) */
	GetStartupInfo(&si);
	if (!CreateProcess(
		NULL, 					/* Module name */
		cp_cmdline, 			/* Command line */
		NULL, NULL, 			/* Security attrs */
		FALSE, 					/* Inhert handles */
		NORMAL_PRIORITY_CLASS,	/* Normal priority */
		NULL,					/* Environment = default */
		NULL,					/* Current directory */
		&si, 					/* Startup info = ours */
		&pi)					/* Destination handle */
		) {
		fprintf(stderr, "Error in CreateProcess: %s\n", GetLastError());
		return 1;
	}

	/* Restore old stdout */
	if (_dup2( oldstdout, _fileno(stdout) ) != 0) {
		fprintf(stderr, "Unable to restore stdout: %s\n", strerror(errno));
		return 1;
	}
	close(oldstdout);

	/* Allocate enough space for the search string */
	g_szchkbuffer = strlen(SEARCH_STRING);
	g_chkbuffer = (char *)calloc(g_szchkbuffer+1,1);
	if (!g_chkbuffer) { perror("calloc"); return 1; }

	/* Loop until we get the search string */
	for (;;) {

		/* Read a new character */
		rc=_read(hpipe[0], rd, PIPE_BUFFER_SIZE);
		if (rc) {
			if (rc == -1) {
				fprintf(stderr, "Error reading from pipe: %s\n", strerror(errno));
				return -1;
			}
			/* Output what we just read */
			fwrite(rd, 1, rc, stderr);

			if (ProcessBuffer(rd, rc))
				break;
		}
	}

	/* Give ssh time to set up tunnel (doesnt do it right away!?!) */
	Sleep(500);

	/* Start vncviwer, continuing once it's closed */
	system("vncviewer localhost:1");

	/* Terminate ssh, if needed */
	TerminateProcess(pi.hProcess, 0);

	/* And close the reading end of the redirected pipe */
	close(hpipe[0]);

	return 0;
}