xref: /openbmc/qemu/chardev/char-fe.c (revision 44b1ff31) 
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 #include "qemu/osdep.h"
25 #include "qemu/error-report.h"
26 #include "qapi/error.h"
27 #include "qapi-visit.h"
28 #include "sysemu/replay.h"
29 
30 #include "chardev/char-fe.h"
31 #include "chardev/char-io.h"
32 #include "chardev/char-mux.h"
33 
34 int qemu_chr_fe_write(CharBackend *be, const uint8_t *buf, int len)
35 {
36     Chardev *s = be->chr;
37 
38     if (!s) {
39         return 0;
40     }
41 
42     return qemu_chr_write(s, buf, len, false);
43 }
44 
45 int qemu_chr_fe_write_all(CharBackend *be, const uint8_t *buf, int len)
46 {
47     Chardev *s = be->chr;
48 
49     if (!s) {
50         return 0;
51     }
52 
53     return qemu_chr_write(s, buf, len, true);
54 }
55 
56 int qemu_chr_fe_read_all(CharBackend *be, uint8_t *buf, int len)
57 {
58     Chardev *s = be->chr;
59     int offset = 0, counter = 10;
60     int res;
61 
62     if (!s || !CHARDEV_GET_CLASS(s)->chr_sync_read) {
63         return 0;
64     }
65 
66     if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_PLAY) {
67         return replay_char_read_all_load(buf);
68     }
69 
70     while (offset < len) {
71     retry:
72         res = CHARDEV_GET_CLASS(s)->chr_sync_read(s, buf + offset,
73                                                   len - offset);
74         if (res == -1 && errno == EAGAIN) {
75             g_usleep(100);
76             goto retry;
77         }
78 
79         if (res == 0) {
80             break;
81         }
82 
83         if (res < 0) {
84             if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_RECORD) {
85                 replay_char_read_all_save_error(res);
86             }
87             return res;
88         }
89 
90         offset += res;
91 
92         if (!counter--) {
93             break;
94         }
95     }
96 
97     if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_RECORD) {
98         replay_char_read_all_save_buf(buf, offset);
99     }
100     return offset;
101 }
102 
103 int qemu_chr_fe_ioctl(CharBackend *be, int cmd, void *arg)
104 {
105     Chardev *s = be->chr;
106     int res;
107 
108     if (!s || !CHARDEV_GET_CLASS(s)->chr_ioctl || qemu_chr_replay(s)) {
109         res = -ENOTSUP;
110     } else {
111         res = CHARDEV_GET_CLASS(s)->chr_ioctl(s, cmd, arg);
112     }
113 
114     return res;
115 }
116 
117 int qemu_chr_fe_get_msgfd(CharBackend *be)
118 {
119     Chardev *s = be->chr;
120     int fd;
121     int res = (qemu_chr_fe_get_msgfds(be, &fd, 1) == 1) ? fd : -1;
122     if (s && qemu_chr_replay(s)) {
123         error_report("Replay: get msgfd is not supported "
124                      "for serial devices yet");
125         exit(1);
126     }
127     return res;
128 }
129 
130 int qemu_chr_fe_get_msgfds(CharBackend *be, int *fds, int len)
131 {
132     Chardev *s = be->chr;
133 
134     if (!s) {
135         return -1;
136     }
137 
138     return CHARDEV_GET_CLASS(s)->get_msgfds ?
139         CHARDEV_GET_CLASS(s)->get_msgfds(s, fds, len) : -1;
140 }
141 
142 int qemu_chr_fe_set_msgfds(CharBackend *be, int *fds, int num)
143 {
144     Chardev *s = be->chr;
145 
146     if (!s) {
147         return -1;
148     }
149 
150     return CHARDEV_GET_CLASS(s)->set_msgfds ?
151         CHARDEV_GET_CLASS(s)->set_msgfds(s, fds, num) : -1;
152 }
153 
154 void qemu_chr_fe_accept_input(CharBackend *be)
155 {
156     Chardev *s = be->chr;
157 
158     if (!s) {
159         return;
160     }
161 
162     if (CHARDEV_GET_CLASS(s)->chr_accept_input) {
163         CHARDEV_GET_CLASS(s)->chr_accept_input(s);
164     }
165     qemu_notify_event();
166 }
167 
168 void qemu_chr_fe_printf(CharBackend *be, const char *fmt, ...)
169 {
170     char buf[CHR_READ_BUF_LEN];
171     va_list ap;
172     va_start(ap, fmt);
173     vsnprintf(buf, sizeof(buf), fmt, ap);
174     /* XXX this blocks entire thread. Rewrite to use
175      * qemu_chr_fe_write and background I/O callbacks */
176     qemu_chr_fe_write_all(be, (uint8_t *)buf, strlen(buf));
177     va_end(ap);
178 }
179 
180 Chardev *qemu_chr_fe_get_driver(CharBackend *be)
181 {
182     /* this is unsafe for the users that support chardev hotswap */
183     assert(be->chr_be_change == NULL);
184     return be->chr;
185 }
186 
187 bool qemu_chr_fe_backend_connected(CharBackend *be)
188 {
189     return !!be->chr;
190 }
191 
192 bool qemu_chr_fe_backend_open(CharBackend *be)
193 {
194     return be->chr && be->chr->be_open;
195 }
196 
197 bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp)
198 {
199     int tag = 0;
200 
201     if (CHARDEV_IS_MUX(s)) {
202         MuxChardev *d = MUX_CHARDEV(s);
203 
204         if (d->mux_cnt >= MAX_MUX) {
205             goto unavailable;
206         }
207 
208         d->backends[d->mux_cnt] = b;
209         tag = d->mux_cnt++;
210     } else if (s->be) {
211         goto unavailable;
212     } else {
213         s->be = b;
214     }
215 
216     b->fe_open = false;
217     b->tag = tag;
218     b->chr = s;
219     return true;
220 
221 unavailable:
222     error_setg(errp, QERR_DEVICE_IN_USE, s->label);
223     return false;
224 }
225 
226 void qemu_chr_fe_deinit(CharBackend *b, bool del)
227 {
228     assert(b);
229 
230     if (b->chr) {
231         qemu_chr_fe_set_handlers(b, NULL, NULL, NULL, NULL, NULL, NULL, true);
232         if (b->chr->be == b) {
233             b->chr->be = NULL;
234         }
235         if (CHARDEV_IS_MUX(b->chr)) {
236             MuxChardev *d = MUX_CHARDEV(b->chr);
237             d->backends[b->tag] = NULL;
238         }
239         if (del) {
240             object_unparent(OBJECT(b->chr));
241         }
242         b->chr = NULL;
243     }
244 }
245 
246 void qemu_chr_fe_set_handlers(CharBackend *b,
247                               IOCanReadHandler *fd_can_read,
248                               IOReadHandler *fd_read,
249                               IOEventHandler *fd_event,
250                               BackendChangeHandler *be_change,
251                               void *opaque,
252                               GMainContext *context,
253                               bool set_open)
254 {
255     Chardev *s;
256     int fe_open;
257 
258     s = b->chr;
259     if (!s) {
260         return;
261     }
262 
263     if (!opaque && !fd_can_read && !fd_read && !fd_event) {
264         fe_open = 0;
265         remove_fd_in_watch(s);
266     } else {
267         fe_open = 1;
268     }
269     b->chr_can_read = fd_can_read;
270     b->chr_read = fd_read;
271     b->chr_event = fd_event;
272     b->chr_be_change = be_change;
273     b->opaque = opaque;
274 
275     qemu_chr_be_update_read_handlers(s, context);
276 
277     if (set_open) {
278         qemu_chr_fe_set_open(b, fe_open);
279     }
280 
281     if (fe_open) {
282         qemu_chr_fe_take_focus(b);
283         /* We're connecting to an already opened device, so let's make sure we
284            also get the open event */
285         if (s->be_open) {
286             qemu_chr_be_event(s, CHR_EVENT_OPENED);
287         }
288     }
289 
290     if (CHARDEV_IS_MUX(s)) {
291         mux_chr_set_handlers(s, context);
292     }
293 }
294 
295 void qemu_chr_fe_take_focus(CharBackend *b)
296 {
297     if (!b->chr) {
298         return;
299     }
300 
301     if (CHARDEV_IS_MUX(b->chr)) {
302         mux_set_focus(b->chr, b->tag);
303     }
304 }
305 
306 int qemu_chr_fe_wait_connected(CharBackend *be, Error **errp)
307 {
308     if (!be->chr) {
309         error_setg(errp, "missing associated backend");
310         return -1;
311     }
312 
313     return qemu_chr_wait_connected(be->chr, errp);
314 }
315 
316 void qemu_chr_fe_set_echo(CharBackend *be, bool echo)
317 {
318     Chardev *chr = be->chr;
319 
320     if (chr && CHARDEV_GET_CLASS(chr)->chr_set_echo) {
321         CHARDEV_GET_CLASS(chr)->chr_set_echo(chr, echo);
322     }
323 }
324 
325 void qemu_chr_fe_set_open(CharBackend *be, int fe_open)
326 {
327     Chardev *chr = be->chr;
328 
329     if (!chr) {
330         return;
331     }
332 
333     if (be->fe_open == fe_open) {
334         return;
335     }
336     be->fe_open = fe_open;
337     if (CHARDEV_GET_CLASS(chr)->chr_set_fe_open) {
338         CHARDEV_GET_CLASS(chr)->chr_set_fe_open(chr, fe_open);
339     }
340 }
341 
342 guint qemu_chr_fe_add_watch(CharBackend *be, GIOCondition cond,
343                             GIOFunc func, void *user_data)
344 {
345     Chardev *s = be->chr;
346     GSource *src;
347     guint tag;
348 
349     if (!s || CHARDEV_GET_CLASS(s)->chr_add_watch == NULL) {
350         return 0;
351     }
352 
353     src = CHARDEV_GET_CLASS(s)->chr_add_watch(s, cond);
354     if (!src) {
355         return 0;
356     }
357 
358     g_source_set_callback(src, (GSourceFunc)func, user_data, NULL);
359     tag = g_source_attach(src, NULL);
360     g_source_unref(src);
361 
362     return tag;
363 }
364 
365 void qemu_chr_fe_disconnect(CharBackend *be)
366 {
367     Chardev *chr = be->chr;
368 
369     if (chr && CHARDEV_GET_CLASS(chr)->chr_disconnect) {
370         CHARDEV_GET_CLASS(chr)->chr_disconnect(chr);
371     }
372 }
373