cosmopolitan/dsp/tty/ident.c

98 lines
4.0 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.internal.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;
}