tty.c

/* tty management for unikey */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <termios.h>
#include "unikey.h"

static struct termios oldterm;
static struct termios t;
static int flags;
int iselksconsole;

#define WRITE(FD, SLIT)             write(FD, SLIT, strlen(SLIT))
#define ENABLE_SAFE_PASTE           "\e[?2004h"
#define ENABLE_MOUSE_TRACKING       "\e[?1000;1002;1015;1006h"
#define ENABLE_ALL_MOUSE_TRACKING   "\e[?1000;1003;1015;1006h"
#define DISABLE_MOUSE_TRACKING      "\e[?1000;1002;1003;1015;1006l"
#define RESET_VIDEO                 "\e[1;0;0m\e[?25h\n"
#define PROBE_DISPLAY_SIZE          "\e7\e[9979;9979H\e[6n\e8"
#define GOTO_LASTLINE               "\e[26;0H\e[0J"

static void onkilled(int sig)
{
    exit(1);                /* calls tty_restore in exit handler */
}

void tty_restore(void)
{
    WRITE(1, DISABLE_MOUSE_TRACKING);
    WRITE(1, RESET_VIDEO);
    if (flags & ExitLastLine)
        WRITE(1, GOTO_LASTLINE);
    tcsetattr(1, TCSADRAIN, &oldterm);
}

void tty_enable_unikey(void)
{
    t.c_cc[VMIN] = 1;         /* requires ESC ESC ESC for ESC */
    t.c_cc[VTIME] = 1;
    t.c_iflag &= ~(INPCK | ISTRIP | PARMRK | INLCR | IGNCR | ICRNL | IXON |
                   IGNBRK | BRKINT);
    if (flags & Utf8)
        t.c_iflag |= IUTF8;         /* correct kernel backspace behaviour */
    t.c_lflag &= ~(IEXTEN | ICANON | ECHO | ECHONL | ISIG);
    if (flags & CatchISig)
        t.c_lflag |= ISIG;
    t.c_cflag &= ~(CSIZE | PARENB);
    t.c_cflag |= CS8;
    tcsetattr(1, TCSADRAIN, &t);
    WRITE(1, ENABLE_SAFE_PASTE);
    if (flags & FullMouseTracking) {
        WRITE(1, ENABLE_ALL_MOUSE_TRACKING);
    } else if (flags & MouseTracking) {
        WRITE(1, ENABLE_MOUSE_TRACKING);
    }
}

void tty_fullbuffer(void)
{
    fflush(stdout);
#if ELKS
    /* use existing stdout buffer to save heap space */
    setvbuf(stdout, (char *)stdout->bufstart, _IOFBF, stdout->bufend - stdout->bufstart);
#else
    setvbuf(stdout, NULL, _IOFBF, 0);
#endif
}

void tty_linebuffer(void)
{
    fflush(stdout);
#if ELKS
    /* use existing stdout buffer to save heap space */
    setvbuf(stdout, (char *)stdout->bufstart, _IOLBF, stdout->bufend - stdout->bufstart);
#else
    setvbuf(stdout, NULL, _IOLBF, 0);
#endif
}

int tty_iselksconsole(int fd)
{
#if ELKS
    char *p = ttyname(fd);

    if (!p) return 0;
    return !strcmp(p, "/dev/tty1") ||
           !strcmp(p, "/dev/tty2") ||
           !strcmp(p, "/dev/tty3");
#else
    return 0;
#endif
}

int tty_init(enum ttyflags f)
{
    static int once;

    flags = f;
    if (!once) {
        if (tcgetattr(1, &oldterm) != -1) {
            atexit(tty_restore);
            signal(SIGTERM, onkilled);
            signal(SIGINT, onkilled);
        } else {
            return -1;
        }
        once = 1;
        memcpy(&t, &oldterm, sizeof(t));
        iselksconsole = tty_iselksconsole(1);
    }
    tty_enable_unikey();
    if (flags & FullBuffer)
        tty_fullbuffer();
    return 0;
}