xref: /openbmc/qemu/chardev/char-stdio.c (revision ddd17313)
1 /*
2  * QEMU System Emulator
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "qemu/module.h"
27 #include "qemu/option.h"
28 #include "qemu/sockets.h"
29 #include "qapi/error.h"
30 #include "chardev/char.h"
31 
32 #ifdef _WIN32
33 #include "chardev/char-win.h"
34 #include "chardev/char-win-stdio.h"
35 #else
36 #include <termios.h>
37 #include "chardev/char-fd.h"
38 #endif
39 
40 #ifndef _WIN32
41 /* init terminal so that we can grab keys */
42 static struct termios oldtty;
43 static int old_fd0_flags;
44 static int old_fd1_flags;
45 static bool stdio_in_use;
46 static bool stdio_allow_signal;
47 static bool stdio_echo_state;
48 
49 static void term_exit(void)
50 {
51     if (stdio_in_use) {
52         tcsetattr(0, TCSANOW, &oldtty);
53         fcntl(0, F_SETFL, old_fd0_flags);
54         fcntl(1, F_SETFL, old_fd1_flags);
55         stdio_in_use = false;
56     }
57 }
58 
59 static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
60 {
61     struct termios tty;
62 
63     stdio_echo_state = echo;
64     tty = oldtty;
65     if (!echo) {
66         tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
67                          | INLCR | IGNCR | ICRNL | IXON);
68         tty.c_oflag |= OPOST;
69         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
70         tty.c_cflag &= ~(CSIZE | PARENB);
71         tty.c_cflag |= CS8;
72         tty.c_cc[VMIN] = 1;
73         tty.c_cc[VTIME] = 0;
74     }
75     if (!stdio_allow_signal) {
76         tty.c_lflag &= ~ISIG;
77     }
78 
79     tcsetattr(0, TCSANOW, &tty);
80 }
81 
82 static void term_stdio_handler(int sig)
83 {
84     /* restore echo after resume from suspend. */
85     qemu_chr_set_echo_stdio(NULL, stdio_echo_state);
86 }
87 
88 static void qemu_chr_open_stdio(Chardev *chr,
89                                 ChardevBackend *backend,
90                                 bool *be_opened,
91                                 Error **errp)
92 {
93     ChardevStdio *opts = backend->u.stdio.data;
94     struct sigaction act;
95 
96     if (is_daemonized()) {
97         error_setg(errp, "cannot use stdio with -daemonize");
98         return;
99     }
100 
101     if (stdio_in_use) {
102         error_setg(errp, "cannot use stdio by multiple character devices");
103         return;
104     }
105 
106     stdio_in_use = true;
107     old_fd0_flags = fcntl(0, F_GETFL);
108     old_fd1_flags = fcntl(1, F_GETFL);
109     tcgetattr(0, &oldtty);
110     if (!g_unix_set_fd_nonblocking(0, true, NULL)) {
111         error_setg_errno(errp, errno, "Failed to set FD nonblocking");
112         return;
113     }
114     atexit(term_exit);
115 
116     memset(&act, 0, sizeof(act));
117     act.sa_handler = term_stdio_handler;
118     sigaction(SIGCONT, &act, NULL);
119 
120     qemu_chr_open_fd(chr, 0, 1);
121 
122     stdio_allow_signal = !opts->has_signal || opts->signal;
123     qemu_chr_set_echo_stdio(chr, false);
124 }
125 #endif
126 
127 static void qemu_chr_parse_stdio(QemuOpts *opts, ChardevBackend *backend,
128                                  Error **errp)
129 {
130     ChardevStdio *stdio;
131 
132     backend->type = CHARDEV_BACKEND_KIND_STDIO;
133     stdio = backend->u.stdio.data = g_new0(ChardevStdio, 1);
134     qemu_chr_parse_common(opts, qapi_ChardevStdio_base(stdio));
135     stdio->has_signal = true;
136     stdio->signal = qemu_opt_get_bool(opts, "signal", true);
137 }
138 
139 static void char_stdio_class_init(ObjectClass *oc, void *data)
140 {
141     ChardevClass *cc = CHARDEV_CLASS(oc);
142 
143     cc->parse = qemu_chr_parse_stdio;
144 #ifndef _WIN32
145     cc->open = qemu_chr_open_stdio;
146     cc->chr_set_echo = qemu_chr_set_echo_stdio;
147 #endif
148 }
149 
150 static void char_stdio_finalize(Object *obj)
151 {
152 #ifndef _WIN32
153     term_exit();
154 #endif
155 }
156 
157 static const TypeInfo char_stdio_type_info = {
158     .name = TYPE_CHARDEV_STDIO,
159 #ifdef _WIN32
160     .parent = TYPE_CHARDEV_WIN_STDIO,
161 #else
162     .parent = TYPE_CHARDEV_FD,
163 #endif
164     .instance_finalize = char_stdio_finalize,
165     .class_init = char_stdio_class_init,
166 };
167 
168 static void register_types(void)
169 {
170     type_register_static(&char_stdio_type_info);
171 }
172 
173 type_init(register_types);
174