qemu/chardev/char-stdio.c
Maxim Mikityanskiy 837864aa6c char-stdio: Restore blocking mode of stdout on exit
qemu_chr_open_fd() sets stdout into non-blocking mode. Restore the old
fd flags on exit to avoid breaking unsuspecting applications that run on
the same terminal after qemu and don't expect to get EAGAIN.

While at at, also ensure term_exit is called once (at the moment it's
called both from char_stdio_finalize() and as the atexit() hook.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2423
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Link: https://lore.kernel.org/r/20240703190812.3459514-1-maxtram95@gmail.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit a0124e333e)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2024-07-05 15:04:11 +03:00

174 lines
4.7 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/module.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 int old_fd1_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);
fcntl(1, F_SETFL, old_fd1_flags);
stdio_in_use = false;
}
}
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);
old_fd1_flags = fcntl(1, F_GETFL);
tcgetattr(0, &oldtty);
if (!g_unix_set_fd_nonblocking(0, true, NULL)) {
error_setg_errno(errp, errno, "Failed to set FD nonblocking");
return;
}
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);
stdio_allow_signal = !opts->has_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);