/*
 * Pseudo-tty backend for pterm.
 */

#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <assert.h>
#include <fcntl.h>
#include <termios.h>
#include <grp.h>
#include <utmp.h>
#include <pwd.h>
#include <time.h>
#include <sys/types.h>

    int master_fd, slave_fd;
    void *frontend;
    char name[FILENAME_MAX];
    int child_pid;
    int term_width, term_height;
    int child_dead, finished;
    int exit_code;
    bufchain output_data;
};

/*
 * We store our pty backends in a tree sorted by master fd, so that
 * when we get an uxsel notification we know which backend instance
 * is the owner of the pty that caused it.
 */

 * pty_argv is a grievous hack to allow a proper argv to be passed
 * through from the Unix command line. Again, it doesn't really
 * make sense outside a one-pty-per-process setup.
 */
char **pty_argv;

static void pty_close(Pty pty);
static void pty_try_write(Pty pty);

#ifndef OMIT_UTMP
static void setup_utmp(char *ttyname, char *location)
{
#ifdef HAVE_LASTLOG
    struct lastlog lastlog_entry;
    FILE *lastlog;

	perror("unlockpt");
	exit(1);
    }

    pty->name[FILENAME_MAX-1] = '\0';
    strncpy(pty->name, ptsname(pty->master_fd), FILENAME_MAX-1);
#endif

    {
        /*
         * Set the pty master into non-blocking mode.
         */
        int i = 1;
        ioctl(pty->master_fd, FIONBIO, &i);
    }

    if (!ptys_by_fd)
	ptys_by_fd = newtree234(pty_compare_by_fd);
    add234(ptys_by_fd, pty);
}

/*

#ifndef OMIT_UTMP
    pid_t pid;
    int pipefd[2];
#endif

    pty = single_pty = snew(struct pty_tag);
    bufchain_init(&pty->output_data);

    /* set the child signal handler straight away; it needs to be set
     * before we ever fork. */
    putty_signal(SIGCHLD, sigchld_handler);
    pty->master_fd = pty->slave_fd = -1;
#ifndef OMIT_UTMP
    pty_stamped_utmp = FALSE;

		    pty->exit_code = 0;
	    } else if (ret < 0) {
		perror("read pty master");
		exit(1);
	    } else if (ret > 0) {
		from_backend(pty->frontend, 0, buf, ret);
	    }
	} else if (event == 2) {
            /*
             * Attempt to send data down the pty.
             */
            pty_try_write(pty);
        }
    }

    if (finished && !pty->finished) {
	uxsel_del(pty->master_fd);
	pty_close(pty);
	pty->master_fd = -1;

    }

    return ret;
}

static void pty_uxsel_setup(Pty pty)
{
    int rwx;

    rwx = 1;                           /* always want to read from pty */
    if (bufchain_size(&pty->output_data))
        rwx |= 2;                      /* might also want to write to it */
    uxsel_set(pty->master_fd, rwx, pty_select_result);

    /*
     * In principle this only needs calling once for all pty
     * backend instances, but it's simplest just to call it every
     * time; uxsel won't mind.
     */
    uxsel_set(pty_signal_pipe[0], 1, pty_select_result);

    /* Either of these may fail `not found'. That's fine with us. */
    del234(ptys_by_pid, pty);
    del234(ptys_by_fd, pty);

    sfree(pty);
}

static void pty_try_write(Pty pty)
{
    void *data;
    int len, ret;

    assert(pty->master_fd >= 0);

    while (bufchain_size(&pty->output_data) > 0) {
        bufchain_prefix(&pty->output_data, &data, &len);
	ret = write(pty->master_fd, data, len);

        if (ret < 0 && (errno == EWOULDBLOCK)) {
            /*
             * We've sent all we can for the moment.
             */
            break;
        }
	if (ret < 0) {
	    perror("write pty master");
	    exit(1);
	}
	bufchain_consume(&pty->output_data, ret);
    }

    pty_uxsel_setup(pty);
}

/*
 * Called to send data down the pty.
 */
static int pty_send(void *handle, char *buf, int len)
{
    Pty pty = (Pty)handle;

    if (pty->master_fd < 0)
	return 0;                      /* ignore all writes if fd closed */


    bufchain_add(&pty->output_data, buf, len);

    pty_try_write(pty);





    return bufchain_size(&pty->output_data);
}

static void pty_close(Pty pty)
{
    if (pty->master_fd >= 0) {
	close(pty->master_fd);
	pty->master_fd = -1;