#include <unistd.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <stdarg.h>
#include <string.h>
#include <termios.h>
#include <pty.h>

#include "pterm.h"
#include "log.h"

#ifndef _PATH_TTY
#define _PATH_TTY "/dev/tty"
#endif
#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif


int
pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
{
    /* openpty(3) exists in OSF/1 and some other os'es */
    char *name;
    int i;

    i = openpty(ptyfd, ttyfd, NULL, NULL, NULL);
    if (i < 0) {
        E_STRERR("%s", "Allocate pseudo terminal");
        return 1;
    }
    name = ttyname(*ttyfd);
    if (!name) {
        E_STRERR("%s", "Invalid ttyname for pseudo terminal");
        abort();
    }

    strncpy(namebuf, name, namebuflen);	/* possible truncation */
    return 0;
}

void
pty_release(const char *tty)
{
    if (chown(tty, (uid_t) 0, (gid_t) 0) < 0) {
        E_STRERR("Change tty owner for '%s'", tty);
    }
    if (chmod(tty, (mode_t) 0666) < 0) {
        E_STRERR("Change tty mode for '%s'", tty);
    }
}

void
pty_make_controlling_tty(int *ttyfd, const char *tty)
{
    int fd;

    /* First disconnect from the old controlling tty. */
    fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
    if (fd >= 0) {
        (void) ioctl(fd, TIOCNOTTY, NULL);
        close(fd);
    }
    if (setsid() < 0)
        E_STRERR("%s", "New session");

    /*
     * Verify that we are successfully disconnected from the controlling
     * tty.
     */
    fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
    if (fd >= 0) {
        E2("%s", "Failed to disconnect from controlling tty.");
        close(fd);
    }
    /* Make it our controlling tty. */
    D("%s", "Setting controlling tty using TIOCSCTTY.");
    if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
        E_STRERR("%s", "ioctl(TIOCSCTTY)");
    if (setpgrp() < 0)
        E_STRERR("%s", "Set new process group");
    fd = open(tty, O_RDWR);
    if (fd < 0)
        E_STRERR("Open tty '%s'", tty);
    else
        close(fd);

    /* Verify that we now have a controlling tty. */
    fd = open(_PATH_TTY, O_WRONLY);
    if (fd < 0)
        E_STRERR("Could not set controlling tty - Open '%s'", tty);
    else
        close(fd);
}

/* Changes the window size associated with the pty. */

void
pty_change_window_size(int ptyfd, unsigned int row,
                       unsigned int col,
                       unsigned int xpixel,
                       unsigned int ypixel)
{
    struct winsize w;

    /* may truncate unsigned int -> unsigned short */
    w.ws_row = row;
    w.ws_col = col;
    w.ws_xpixel = xpixel;
    w.ws_ypixel = ypixel;
    (void) ioctl(ptyfd, TIOCSWINSZ, &w);
}

void
pty_setowner(struct passwd *pw, const char *tty)
{
    struct group *grp;
    gid_t gid;
    mode_t mode;
    struct stat st;

    /* Determine the group to make the owner of the tty. */
    grp = getgrnam("tty");
    gid = (grp != NULL) ? grp->gr_gid : pw->pw_gid;
    mode = (grp != NULL) ? 0620 : 0600;

    /*
     * Change owner and mode of the tty as required.
     * Warn but continue if filesystem is read-only and the uids match/
     * tty is owned by root.
     */
    if (stat(tty, &st))
        FATAL("Change owner of %s", tty);

#ifdef WITH_SELINUX
    ssh_selinux_setup_pty(pw->pw_name, tty);
#endif

    if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
        if (chown(tty, pw->pw_uid, gid) < 0) {
            if (errno == EROFS &&
                (st.st_uid == pw->pw_uid || st.st_uid == 0))
            {
                D("Change owner of '%s' to %u:%u",
                    tty, (unsigned) pw->pw_uid,
                    (unsigned) gid);
            } else {
                FATAL("Change owner of '%s' to %u:%u",
                    tty, (unsigned) pw->pw_uid,
                    (unsigned) gid);
            }
        }
    }

    if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
        if (chmod(tty, mode) < 0) {
            if (errno == EROFS &&
                (st.st_mode & (S_IRGRP | S_IROTH)) == 0)
            {
                D("Change mode of '%s' to 0%o",
                    tty, (unsigned) mode);
            } else {
                FATAL("Change mode of '%s' to 0%o",
                    tty, (unsigned) mode);
            }
        }
    }
}

/* Disconnect from the controlling tty. */
void
disconnect_controlling_tty(void)
{
    int fd;

    if ((fd = open(_PATH_TTY, O_RDWR | O_NOCTTY)) >= 0) {
        (void) ioctl(fd, TIOCNOTTY, NULL);
        close(fd);
    }
}