linux-user: Add support for a group of btrfs ioctls used for snapshots
[qemu.git] / chardev / char-pty.c
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-common.h"
27 #include "qapi/error.h"
28 #include "chardev/char.h"
29 #include "io/channel-file.h"
30 #include "qemu/sockets.h"
31 #include "qemu/error-report.h"
32 #include "qemu/module.h"
33 #include "qemu/qemu-print.h"
34
35 #include "chardev/char-io.h"
36
37 typedef struct {
38 Chardev parent;
39 QIOChannel *ioc;
40 int read_bytes;
41
42 int connected;
43 GSource *timer_src;
44 } PtyChardev;
45
46 #define PTY_CHARDEV(obj) OBJECT_CHECK(PtyChardev, (obj), TYPE_CHARDEV_PTY)
47
48 static void pty_chr_state(Chardev *chr, int connected);
49
50 static void pty_chr_timer_cancel(PtyChardev *s)
51 {
52 if (s->timer_src) {
53 g_source_destroy(s->timer_src);
54 g_source_unref(s->timer_src);
55 s->timer_src = NULL;
56 }
57 }
58
59 static gboolean pty_chr_timer(gpointer opaque)
60 {
61 struct Chardev *chr = CHARDEV(opaque);
62 PtyChardev *s = PTY_CHARDEV(opaque);
63
64 pty_chr_timer_cancel(s);
65 if (!s->connected) {
66 /* Next poll ... */
67 qemu_chr_be_update_read_handlers(chr, chr->gcontext);
68 }
69 return FALSE;
70 }
71
72 static void pty_chr_rearm_timer(Chardev *chr, int ms)
73 {
74 PtyChardev *s = PTY_CHARDEV(chr);
75 char *name;
76
77 pty_chr_timer_cancel(s);
78 name = g_strdup_printf("pty-timer-%s", chr->label);
79 s->timer_src = qemu_chr_timeout_add_ms(chr, ms, pty_chr_timer, chr);
80 g_source_set_name(s->timer_src, name);
81 g_free(name);
82 }
83
84 static void pty_chr_update_read_handler(Chardev *chr)
85 {
86 PtyChardev *s = PTY_CHARDEV(chr);
87 GPollFD pfd;
88 int rc;
89 QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
90
91 pfd.fd = fioc->fd;
92 pfd.events = G_IO_OUT;
93 pfd.revents = 0;
94 do {
95 rc = g_poll(&pfd, 1, 0);
96 } while (rc == -1 && errno == EINTR);
97 assert(rc >= 0);
98
99 if (pfd.revents & G_IO_HUP) {
100 pty_chr_state(chr, 0);
101 } else {
102 pty_chr_state(chr, 1);
103 }
104 }
105
106 static int char_pty_chr_write(Chardev *chr, const uint8_t *buf, int len)
107 {
108 PtyChardev *s = PTY_CHARDEV(chr);
109
110 if (!s->connected) {
111 return len;
112 }
113 return io_channel_send(s->ioc, buf, len);
114 }
115
116 static GSource *pty_chr_add_watch(Chardev *chr, GIOCondition cond)
117 {
118 PtyChardev *s = PTY_CHARDEV(chr);
119 if (!s->connected) {
120 return NULL;
121 }
122 return qio_channel_create_watch(s->ioc, cond);
123 }
124
125 static int pty_chr_read_poll(void *opaque)
126 {
127 Chardev *chr = CHARDEV(opaque);
128 PtyChardev *s = PTY_CHARDEV(opaque);
129
130 s->read_bytes = qemu_chr_be_can_write(chr);
131 return s->read_bytes;
132 }
133
134 static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
135 {
136 Chardev *chr = CHARDEV(opaque);
137 PtyChardev *s = PTY_CHARDEV(opaque);
138 gsize len;
139 uint8_t buf[CHR_READ_BUF_LEN];
140 ssize_t ret;
141
142 len = sizeof(buf);
143 if (len > s->read_bytes) {
144 len = s->read_bytes;
145 }
146 if (len == 0) {
147 return TRUE;
148 }
149 ret = qio_channel_read(s->ioc, (char *)buf, len, NULL);
150 if (ret <= 0) {
151 pty_chr_state(chr, 0);
152 return FALSE;
153 } else {
154 pty_chr_state(chr, 1);
155 qemu_chr_be_write(chr, buf, ret);
156 }
157 return TRUE;
158 }
159
160 static void pty_chr_state(Chardev *chr, int connected)
161 {
162 PtyChardev *s = PTY_CHARDEV(chr);
163
164 if (!connected) {
165 remove_fd_in_watch(chr);
166 s->connected = 0;
167 /* (re-)connect poll interval for idle guests: once per second.
168 * We check more frequently in case the guests sends data to
169 * the virtual device linked to our pty. */
170 pty_chr_rearm_timer(chr, 1000);
171 } else {
172 pty_chr_timer_cancel(s);
173 if (!s->connected) {
174 s->connected = 1;
175 qemu_chr_be_event(chr, CHR_EVENT_OPENED);
176 }
177 if (!chr->gsource) {
178 chr->gsource = io_add_watch_poll(chr, s->ioc,
179 pty_chr_read_poll,
180 pty_chr_read,
181 chr, chr->gcontext);
182 }
183 }
184 }
185
186 static void char_pty_finalize(Object *obj)
187 {
188 Chardev *chr = CHARDEV(obj);
189 PtyChardev *s = PTY_CHARDEV(obj);
190
191 pty_chr_state(chr, 0);
192 object_unref(OBJECT(s->ioc));
193 pty_chr_timer_cancel(s);
194 qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
195 }
196
197 static void char_pty_open(Chardev *chr,
198 ChardevBackend *backend,
199 bool *be_opened,
200 Error **errp)
201 {
202 PtyChardev *s;
203 int master_fd, slave_fd;
204 char pty_name[PATH_MAX];
205 char *name;
206
207 master_fd = qemu_openpty_raw(&slave_fd, pty_name);
208 if (master_fd < 0) {
209 error_setg_errno(errp, errno, "Failed to create PTY");
210 return;
211 }
212
213 close(slave_fd);
214 qemu_set_nonblock(master_fd);
215
216 chr->filename = g_strdup_printf("pty:%s", pty_name);
217 qemu_printf("char device redirected to %s (label %s)\n",
218 pty_name, chr->label);
219
220 s = PTY_CHARDEV(chr);
221 s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
222 name = g_strdup_printf("chardev-pty-%s", chr->label);
223 qio_channel_set_name(QIO_CHANNEL(s->ioc), name);
224 g_free(name);
225 s->timer_src = NULL;
226 *be_opened = false;
227 }
228
229 static void char_pty_class_init(ObjectClass *oc, void *data)
230 {
231 ChardevClass *cc = CHARDEV_CLASS(oc);
232
233 cc->open = char_pty_open;
234 cc->chr_write = char_pty_chr_write;
235 cc->chr_update_read_handler = pty_chr_update_read_handler;
236 cc->chr_add_watch = pty_chr_add_watch;
237 }
238
239 static const TypeInfo char_pty_type_info = {
240 .name = TYPE_CHARDEV_PTY,
241 .parent = TYPE_CHARDEV,
242 .instance_size = sizeof(PtyChardev),
243 .instance_finalize = char_pty_finalize,
244 .class_init = char_pty_class_init,
245 };
246
247 static void register_types(void)
248 {
249 type_register_static(&char_pty_type_info);
250 }
251
252 type_init(register_types);