xref: /openbmc/qemu/chardev/char-stdio.c (revision 6016b7b4)
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 bool stdio_in_use;
45 static bool stdio_allow_signal;
46 static bool stdio_echo_state;
47 
48 static void term_exit(void)
49 {
50     if (stdio_in_use) {
51         tcsetattr(0, TCSANOW, &oldtty);
52         fcntl(0, F_SETFL, old_fd0_flags);
53     }
54 }
55 
56 static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
57 {
58     struct termios tty;
59 
60     stdio_echo_state = echo;
61     tty = oldtty;
62     if (!echo) {
63         tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
64                          | INLCR | IGNCR | ICRNL | IXON);
65         tty.c_oflag |= OPOST;
66         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
67         tty.c_cflag &= ~(CSIZE | PARENB);
68         tty.c_cflag |= CS8;
69         tty.c_cc[VMIN] = 1;
70         tty.c_cc[VTIME] = 0;
71     }
72     if (!stdio_allow_signal) {
73         tty.c_lflag &= ~ISIG;
74     }
75 
76     tcsetattr(0, TCSANOW, &tty);
77 }
78 
79 static void term_stdio_handler(int sig)
80 {
81     /* restore echo after resume from suspend. */
82     qemu_chr_set_echo_stdio(NULL, stdio_echo_state);
83 }
84 
85 static void qemu_chr_open_stdio(Chardev *chr,
86                                 ChardevBackend *backend,
87                                 bool *be_opened,
88                                 Error **errp)
89 {
90     ChardevStdio *opts = backend->u.stdio.data;
91     struct sigaction act;
92 
93     if (is_daemonized()) {
94         error_setg(errp, "cannot use stdio with -daemonize");
95         return;
96     }
97 
98     if (stdio_in_use) {
99         error_setg(errp, "cannot use stdio by multiple character devices");
100         return;
101     }
102 
103     stdio_in_use = true;
104     old_fd0_flags = fcntl(0, F_GETFL);
105     tcgetattr(0, &oldtty);
106     qemu_set_nonblock(0);
107     atexit(term_exit);
108 
109     memset(&act, 0, sizeof(act));
110     act.sa_handler = term_stdio_handler;
111     sigaction(SIGCONT, &act, NULL);
112 
113     qemu_chr_open_fd(chr, 0, 1);
114 
115     stdio_allow_signal = !opts->has_signal || opts->signal;
116     qemu_chr_set_echo_stdio(chr, false);
117 }
118 #endif
119 
120 static void qemu_chr_parse_stdio(QemuOpts *opts, ChardevBackend *backend,
121                                  Error **errp)
122 {
123     ChardevStdio *stdio;
124 
125     backend->type = CHARDEV_BACKEND_KIND_STDIO;
126     stdio = backend->u.stdio.data = g_new0(ChardevStdio, 1);
127     qemu_chr_parse_common(opts, qapi_ChardevStdio_base(stdio));
128     stdio->has_signal = true;
129     stdio->signal = qemu_opt_get_bool(opts, "signal", true);
130 }
131 
132 static void char_stdio_class_init(ObjectClass *oc, void *data)
133 {
134     ChardevClass *cc = CHARDEV_CLASS(oc);
135 
136     cc->parse = qemu_chr_parse_stdio;
137 #ifndef _WIN32
138     cc->open = qemu_chr_open_stdio;
139     cc->chr_set_echo = qemu_chr_set_echo_stdio;
140 #endif
141 }
142 
143 static void char_stdio_finalize(Object *obj)
144 {
145 #ifndef _WIN32
146     term_exit();
147 #endif
148 }
149 
150 static const TypeInfo char_stdio_type_info = {
151     .name = TYPE_CHARDEV_STDIO,
152 #ifdef _WIN32
153     .parent = TYPE_CHARDEV_WIN_STDIO,
154 #else
155     .parent = TYPE_CHARDEV_FD,
156 #endif
157     .instance_finalize = char_stdio_finalize,
158     .class_init = char_stdio_class_init,
159 };
160 
161 static void register_types(void)
162 {
163     type_register_static(&char_stdio_type_info);
164 }
165 
166 type_init(register_types);
167