@samitouri / QOSamiQemu
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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 "chardev/char-io.h"
26
27 typedef struct IOWatchPoll {
28 GSource parent;
29
30 QIOChannel *ioc;
31 GSource *src;
32
33 IOCanReadHandler *fd_can_read;
34 GSourceFunc fd_read;
35 void *opaque;
36 GMainContext *context;
37 } IOWatchPoll;
38
39 static IOWatchPoll *io_watch_poll_from_source(GSource *source)
40 {
41 return container_of(source, IOWatchPoll, parent);
42 }
43
44 static gboolean io_watch_poll_prepare(GSource *source,
45 gint *timeout)
46 {
47 IOWatchPoll *iwp = io_watch_poll_from_source(source);
48 bool now_active = iwp->fd_can_read(iwp->opaque) > 0;
49 bool was_active = iwp->src != NULL;
50 if (was_active == now_active) {
51 return FALSE;
52 }
53
54 /*
55 * We do not register the QIOChannel watch as a child GSource.
56 * The 'prepare' function on the parent GSource will be
57 * skipped if a child GSource's 'prepare' function indicates
58 * readiness. We need this prepare function be guaranteed
59 * to run on *every* iteration of the main loop, because
60 * it is critical to ensure we remove the QIOChannel watch
61 * if 'fd_can_read' indicates the frontend cannot receive
62 * more data.
63 */
64 if (now_active) {
65 iwp->src = qio_channel_create_watch(
66 iwp->ioc, G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
67 g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
68 g_source_attach(iwp->src, iwp->context);
69 } else {
70 g_source_destroy(iwp->src);
71 g_source_unref(iwp->src);
72 iwp->src = NULL;
73 }
74 return FALSE;
75 }
76
77 static gboolean io_watch_poll_check(GSource *source)
78 {
79 return FALSE;
80 }
81
82 static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback,
83 gpointer user_data)
84 {
85 abort();
86 }
87
88 static void io_watch_poll_finalize(GSource *source)
89 {
90 IOWatchPoll *iwp = io_watch_poll_from_source(source);
91
92 object_unref(OBJECT(iwp->ioc));
93
94 if (iwp->src) {
95 g_source_destroy(iwp->src);
96 g_source_unref(iwp->src);
97 iwp->src = NULL;
98 }
99 }
100
101 static GSourceFuncs io_watch_poll_funcs = {
102 .prepare = io_watch_poll_prepare,
103 .check = io_watch_poll_check,
104 .dispatch = io_watch_poll_dispatch,
105 .finalize = io_watch_poll_finalize,
106 };
107
108 GSource *io_add_watch_poll(Chardev *chr,
109 QIOChannel *ioc,
110 IOCanReadHandler *fd_can_read,
111 QIOChannelFunc fd_read,
112 gpointer user_data,
113 GMainContext *context)
114 {
115 IOWatchPoll *iwp;
116 char *name;
117
118 iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
119 sizeof(IOWatchPoll));
120 iwp->fd_can_read = fd_can_read;
121 iwp->opaque = user_data;
122 iwp->ioc = ioc;
123 object_ref(OBJECT(iwp->ioc));
124
125 iwp->fd_read = (GSourceFunc) fd_read;
126 iwp->src = NULL;
127 iwp->context = context;
128
129 name = g_strdup_printf("chardev-iowatch-%s", chr->label);
130 g_source_set_name((GSource *)iwp, name);
131 g_free(name);
132
133 g_source_attach(&iwp->parent, context);
134 g_source_unref(&iwp->parent);
135 return (GSource *)iwp;
136 }
137
138 static void io_remove_watch_poll(GSource *source)
139 {
140 IOWatchPoll *iwp;
141
142 iwp = io_watch_poll_from_source(source);
143 g_source_destroy(&iwp->parent);
144 }
145
146 void remove_fd_in_watch(Chardev *chr)
147 {
148 if (chr->gsource) {
149 io_remove_watch_poll(chr->gsource);
150 chr->gsource = NULL;
151 }
152 }
153
154 int io_channel_send_full(QIOChannel *ioc,
155 const void *buf, size_t len,
156 int *fds, size_t nfds)
157 {
158 size_t offset = 0;
159
160 while (offset < len) {
161 ssize_t ret = 0;
162 struct iovec iov = { .iov_base = (char *)buf + offset,
163 .iov_len = len - offset };
164
165 ret = qio_channel_writev_full(
166 ioc, &iov, 1,
167 fds, nfds, 0, NULL);
168 if (ret == QIO_CHANNEL_ERR_BLOCK) {
169 if (offset) {
170 return offset;
171 }
172
173 errno = EAGAIN;
174 return -1;
175 } else if (ret < 0) {
176 errno = EINVAL;
177 return -1;
178 }
179
180 offset += ret;
181 }
182
183 return offset;
184 }
185
186 int io_channel_send(QIOChannel *ioc, const void *buf, size_t len)
187 {
188 return io_channel_send_full(ioc, buf, len, NULL, 0);
189 }
190
191 void remove_listener_fd_in_watch(Chardev *chr)
192 {
193 ChardevClass *cc = CHARDEV_GET_CLASS(chr);
194 if (cc->chr_listener_cleanup) {
195 cc->chr_listener_cleanup(chr);
196 }
197 }