/*	$Id: ssh_ui.c,v 1.6 2001/02/11 03:35:15 tls Exp $	*/

/*
 * Copyright (c) 2001 Jason R. Thorpe.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This module implements the FreSSH user interface.
 */

#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

#include "ssh_ui.h"

struct ui_state {
	int	ui_fd_in;	/* input TTY file descriptor */
	int	ui_fd_out;	/* output TTY file descriptor */
	int	ui_needclose;	/* need to close the FDs */
	struct termios ui_term;	/* save terminal state */
};

/*
 * ui_open:
 *
 *	Open the user interface.
 */
static int
ui_open(struct ui_state *ui)
{
	int fd;

	fd = open("/dev/tty", O_RDWR);
	if (fd == -1) {
		/* Use stdin and stderr. */
		ui->ui_fd_in = fileno(stdin);
		ui->ui_fd_out = fileno(stderr);
		ui->ui_needclose = 0;
	} else {
		ui->ui_fd_in = ui->ui_fd_out = fd;
		ui->ui_needclose = 1;
	}

	/*
	 * Flush stdout and stderr so our messages
	 * won't get garbled.
	 */
	fflush(stdout);
	fflush(stderr);

	return (0);
}

/*
 * ui_close:
 *
 *	Close the user interface.
 */
static void
ui_close(struct ui_state *ui)
{

	if (ui->ui_needclose) {
		(void) close(ui->ui_fd_in);
		if (ui->ui_fd_in != ui->ui_fd_out)
			(void) close(ui->ui_fd_out);
	}
}

/*
 * ui_echo_disable:
 *
 *	Disable character echo on the user interface.
 */
static int
ui_echo_disable(struct ui_state *ui)
{
	struct termios term;

	if (tcgetattr(ui->ui_fd_in, &ui->ui_term) != 0)
		return (-1);
	term = ui->ui_term;	/* structure copy */
	term.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
	if (tcsetattr(ui->ui_fd_in, TCSANOW, &term) != 0)
		return (-1);

	return (0);
}

/*
 * ui_echo_restore:
 *
 *	Restore character echo on the user interface.
 */
static int
ui_echo_restore(struct ui_state *ui)
{

	if (tcsetattr(ui->ui_fd_in, TCSANOW, &ui->ui_term) != 0)
		return (-1);

	return (0);
}

/*
 * ui_output:
 *
 *	Send output to the user interface.
 */
static size_t
ui_output(struct ui_state *ui, const char *buf, size_t bufsize)
{

	return (write(ui->ui_fd_out, buf, bufsize));
}

/*
 * ui_input:
 *
 *	Get input from the user interface.
 */
static size_t
ui_input(struct ui_state *ui, char *buf, size_t bufsize, int echo)
{
	size_t rv;
	char ch;

	if (echo == 0)
		ui_echo_disable(ui);

	for (rv = 0;;) {
		if (read(ui->ui_fd_in, &ch, 1) != 1)
			break;
		if (ch == '\n')
			break;
		if (rv < bufsize)
			buf[rv++] = ch;
	}
	buf[rv] = '\0';

	if (echo == 0) {
		ui_echo_restore(ui);
		(void) ui_output(ui, "\n", 1);
	}

	return (rv);
}

/*
 * ssh_ui_prompt:
 *
 *	Present a prompt to the user and get a response.  Only
 *	echo the response if requested.
 */
int
ssh_ui_prompt(char **pp, const char *prompt, int echo)
{
	char buf[128];
	struct ui_state ui;
	size_t len;
	int rv = 0;

	if (ui_open(&ui) < 0)
		return (-1);

	if (prompt != NULL) {
		/* Write the prompt. */
		(void) ui_output(&ui, prompt, strlen(prompt));
	}

	/* Get the response. */
	len = ui_input(&ui, buf, sizeof(buf), echo);
	if (len <= 0) {
		/* NL or interrupt. */
		buf[0] = '\0';
	}

	if (rv == 0) {
		*pp = strdup(buf);
		if (*pp == NULL)
			rv = -1;
	}

	memset(buf, 0, sizeof(buf));

	ui_close(&ui);

	return (rv);
}

/*
 * ssh_ui_message:
 *
 *	Write a message to the user interface.
 */
void
ssh_ui_message(const char *message)
{
	struct ui_state ui;

	if (ui_open(&ui) < 0)
		return;

	(void) ui_output(&ui, message, strlen(message));
	(void) ui_output(&ui, "\n", 1);

	ui_close(&ui);
}