cosmopolitan/dsp/tty/ident.c
Justine Tunney 9e3e985ae5 Make terminal ui binaries work well everywhere
Here's some screenshots of an emulator tui program that was compiled on
Linux, then scp'd it to Windows, Mac, and FreeBSD.

https://justine.storage.googleapis.com/blinkenlights-cmdexe.png
https://justine.storage.googleapis.com/blinkenlights-imac.png
https://justine.storage.googleapis.com/blinkenlights-freebsd.png
https://justine.storage.googleapis.com/blinkenlights-lisp.png

How is this even possible that we have a nontrivial ui binary that just
works on Mac, Windows, Linux, and BSD? Surely a first ever achievement.

Fixed many bugs. Bootstrapped John McCarthy's metacircular evaluator on
bare metal in half the size of Altair BASIC (about 2.5kb) and ran it in
emulator for fun and profit.
2020-10-19 06:38:31 -07:00

97 lines
4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "dsp/tty/tty.h"
#include "libc/bits/safemacros.h"
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/calls/termios.h"
#include "libc/fmt/fmt.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/sock/sock.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/poll.h"
#include "libc/sysv/errfuns.h"
/* TODO(jart): DELETE */
static int ttyident_probe(struct TtyIdent *ti, int ttyinfd, int ttyoutfd,
const char *msg) {
ssize_t rc;
size_t got;
char buf[64];
int id, version;
if ((rc = write(ttyoutfd, msg, strlen(msg))) != -1) {
TryAgain:
if ((rc = read(ttyinfd, buf, sizeof(buf))) != -1) {
buf[min((got = (size_t)rc), sizeof(buf) - 1)] = '\0';
if (sscanf(buf, "\e[>%d;%d", &id, &version) >= 1) {
ti->id = id;
ti->version = version;
rc = 0;
} else {
rc = eio();
}
} else if (errno == EINTR) {
goto TryAgain;
} else if (errno == EAGAIN) {
if (poll((struct pollfd[]){{ttyinfd, POLLIN}}, 1, 100) != 0) {
goto TryAgain;
} else {
rc = etimedout();
}
}
}
return rc;
}
/**
* Identifies teletypewriter.
*
* For example, we can tell if process is running in a GNU Screen
* session Gnome Terminal.
*
* @return object if TTY responds, or NULL w/ errno
* @see ttyidentclear()
*/
int ttyident(struct TtyIdent *ti, int ttyinfd, int ttyoutfd) {
int rc;
struct termios old;
struct TtyIdent outer;
rc = -1;
if (!IsWindows()) {
if (ttyconfig(ttyinfd, ttysetrawdeadline, 3, &old) != -1) {
if (ttyident_probe(ti, ttyinfd, ttyoutfd, "\e[>c") != -1) {
rc = 0;
memset(&outer, 0, sizeof(outer));
if (ti->id == 83 /* GNU Screen */ && (ti->next || weaken(malloc)) &&
ttyident_probe(&outer, ttyinfd, ttyoutfd, "\eP\e[>c\e\\") != -1 &&
(ti->next = (ti->next ? ti->next
: weaken(malloc)(sizeof(struct TtyIdent))))) {
memcpy(ti->next, &outer, sizeof(outer));
} else {
free_s(&ti->next);
}
}
ttyrestore(ttyinfd, &old);
}
}
return rc;
}