qemu-e2k/chardev/char-stdio.c
Daniel P. Berrangé 1507bd136f chardev: don't splatter terminal settings on exit if not previously set
The stdio chardev finalize method calls term_exit() to restore the
original terminal settings that were saved in the "oldtty" global. If
the qemu_chr_open_stdio() method exited with an error, we might not have
any original terminal settings saved in "oldtty" yet.

eg

  $ qemu-system-x86_64 -monitor stdio -daemonize
  qemu-system-x86_64: -monitor stdio: cannot use stdio with -daemonize

will cause QEMU to splatter the terminal settings with an all-zeros
"struct termios", with predictably unpleasant results. Fortunately the
existing "stdio_in_use" flag is suitable witness for whether "oldtty"
contains settings that need restoring.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20180604123043.13985-1-berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-06-28 19:05:30 +02:00

168 lines
4.5 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu/option.h"
#include "qemu/sockets.h"
#include "qapi/error.h"
#include "chardev/char.h"
#ifdef _WIN32
#include "chardev/char-win.h"
#include "chardev/char-win-stdio.h"
#else
#include <termios.h>
#include "chardev/char-fd.h"
#endif
#ifndef _WIN32
/* init terminal so that we can grab keys */
static struct termios oldtty;
static int old_fd0_flags;
static bool stdio_in_use;
static bool stdio_allow_signal;
static bool stdio_echo_state;
static void term_exit(void)
{
if (stdio_in_use) {
tcsetattr(0, TCSANOW, &oldtty);
fcntl(0, F_SETFL, old_fd0_flags);
}
}
static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
{
struct termios tty;
stdio_echo_state = echo;
tty = oldtty;
if (!echo) {
tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
| INLCR | IGNCR | ICRNL | IXON);
tty.c_oflag |= OPOST;
tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
tty.c_cflag &= ~(CSIZE | PARENB);
tty.c_cflag |= CS8;
tty.c_cc[VMIN] = 1;
tty.c_cc[VTIME] = 0;
}
if (!stdio_allow_signal) {
tty.c_lflag &= ~ISIG;
}
tcsetattr(0, TCSANOW, &tty);
}
static void term_stdio_handler(int sig)
{
/* restore echo after resume from suspend. */
qemu_chr_set_echo_stdio(NULL, stdio_echo_state);
}
static void qemu_chr_open_stdio(Chardev *chr,
ChardevBackend *backend,
bool *be_opened,
Error **errp)
{
ChardevStdio *opts = backend->u.stdio.data;
struct sigaction act;
if (is_daemonized()) {
error_setg(errp, "cannot use stdio with -daemonize");
return;
}
if (stdio_in_use) {
error_setg(errp, "cannot use stdio by multiple character devices");
return;
}
stdio_in_use = true;
old_fd0_flags = fcntl(0, F_GETFL);
tcgetattr(0, &oldtty);
qemu_set_nonblock(0);
atexit(term_exit);
memset(&act, 0, sizeof(act));
act.sa_handler = term_stdio_handler;
sigaction(SIGCONT, &act, NULL);
qemu_chr_open_fd(chr, 0, 1);
if (opts->has_signal) {
stdio_allow_signal = opts->signal;
}
qemu_chr_set_echo_stdio(chr, false);
}
#endif
static void qemu_chr_parse_stdio(QemuOpts *opts, ChardevBackend *backend,
Error **errp)
{
ChardevStdio *stdio;
backend->type = CHARDEV_BACKEND_KIND_STDIO;
stdio = backend->u.stdio.data = g_new0(ChardevStdio, 1);
qemu_chr_parse_common(opts, qapi_ChardevStdio_base(stdio));
stdio->has_signal = true;
stdio->signal = qemu_opt_get_bool(opts, "signal", true);
}
static void char_stdio_class_init(ObjectClass *oc, void *data)
{
ChardevClass *cc = CHARDEV_CLASS(oc);
cc->parse = qemu_chr_parse_stdio;
#ifndef _WIN32
cc->open = qemu_chr_open_stdio;
cc->chr_set_echo = qemu_chr_set_echo_stdio;
#endif
}
static void char_stdio_finalize(Object *obj)
{
#ifndef _WIN32
term_exit();
#endif
}
static const TypeInfo char_stdio_type_info = {
.name = TYPE_CHARDEV_STDIO,
#ifdef _WIN32
.parent = TYPE_CHARDEV_WIN_STDIO,
#else
.parent = TYPE_CHARDEV_FD,
#endif
.instance_finalize = char_stdio_finalize,
.class_init = char_stdio_class_init,
};
static void register_types(void)
{
type_register_static(&char_stdio_type_info);
}
type_init(register_types);