toaruos/apps/ttysize.c
2022-01-30 21:25:27 +09:00

114 lines
2.2 KiB
C

/**
* @brief ttysize - Magically divine terminal size
*
* This is called by getty to determine the size of foreign
* terminals, such as ones attached over serial.
*
* It works by placing the cursor in the lower right of the
* screen and requesting its position. Note that typing things
* while this happens can cause problems. Maybe we can flush
* stdin before doing this to try to avoid any conflicting data?
*
* @copyright
* This file is part of ToaruOS and is released under the terms
* of the NCSA / University of Illinois License - see LICENSE.md
* Copyright (C) 2018 K. Lange
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/fswait.h>
static struct termios old;
static void set_unbuffered() {
tcgetattr(fileno(stdin), &old);
struct termios new = old;
new.c_lflag &= (~ICANON & ~ECHO);
tcsetattr(fileno(stdin), TCSAFLUSH, &new);
}
static void set_buffered() {
tcsetattr(fileno(stdin), TCSAFLUSH, &old);
}
static int getc_timeout(FILE * f, int timeout) {
int fds[1] = {fileno(f)};
int index = fswait2(1,fds,timeout);
if (index == 0) {
return fgetc(f);
} else {
return -1;
}
}
static void divine_size(int * width, int * height) {
set_unbuffered();
*width = 80;
*height = 24;
fprintf(stderr, "\033[s\033[1000;1000H\033[6n\033[u");
fflush(stderr);
char buf[1024] = {0};
size_t i = 0;
while (1) {
int c = getc_timeout(stdin, 200);
if (c == 'R') break;
if (c == -1) goto _done;
if (c == '\033') continue;
if (c == '[') continue;
buf[i++] = c;
}
char * s = strstr(buf, ";");
if (s) {
*(s++) = '\0';
*height = atoi(buf);
*width = atoi(s);
}
_done:
fflush(stderr);
set_buffered();
}
int main(int argc, char * argv[]) {
int width, height;
int opt;
int quiet = 0;
while ((opt = getopt(argc, argv, "q")) != -1) {
switch (opt) {
case 'q':
quiet = 1;
break;
}
}
if (optind + 2 == argc) {
width = atoi(argv[optind]);
height = atoi(argv[optind+1]);
} else {
divine_size(&width, &height);
}
struct winsize w;
w.ws_col = width;
w.ws_row = height;
w.ws_xpixel = 0;
w.ws_ypixel = 0;
ioctl(0, TIOCSWINSZ, &w);
if (!quiet) {
fprintf(stderr, "%dx%d\n", width, height);
}
return 0;
}