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
io_watch_poll_from_source(GSource * source)39 static IOWatchPoll *io_watch_poll_from_source(GSource *source)
40 {
41 return container_of(source, IOWatchPoll, parent);
42 }
43
io_watch_poll_prepare(GSource * source,gint * timeout)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
io_watch_poll_check(GSource * source)77 static gboolean io_watch_poll_check(GSource *source)
78 {
79 return FALSE;
80 }
81
io_watch_poll_dispatch(GSource * source,GSourceFunc callback,gpointer user_data)82 static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback,
83 gpointer user_data)
84 {
85 abort();
86 }
87
io_watch_poll_finalize(GSource * source)88 static void io_watch_poll_finalize(GSource *source)
89 {
90 IOWatchPoll *iwp = io_watch_poll_from_source(source);
91 if (iwp->src) {
92 g_source_destroy(iwp->src);
93 g_source_unref(iwp->src);
94 iwp->src = NULL;
95 }
96 }
97
98 static GSourceFuncs io_watch_poll_funcs = {
99 .prepare = io_watch_poll_prepare,
100 .check = io_watch_poll_check,
101 .dispatch = io_watch_poll_dispatch,
102 .finalize = io_watch_poll_finalize,
103 };
104
io_add_watch_poll(Chardev * chr,QIOChannel * ioc,IOCanReadHandler * fd_can_read,QIOChannelFunc fd_read,gpointer user_data,GMainContext * context)105 GSource *io_add_watch_poll(Chardev *chr,
106 QIOChannel *ioc,
107 IOCanReadHandler *fd_can_read,
108 QIOChannelFunc fd_read,
109 gpointer user_data,
110 GMainContext *context)
111 {
112 IOWatchPoll *iwp;
113 char *name;
114
115 iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
116 sizeof(IOWatchPoll));
117 iwp->fd_can_read = fd_can_read;
118 iwp->opaque = user_data;
119 iwp->ioc = ioc;
120 iwp->fd_read = (GSourceFunc) fd_read;
121 iwp->src = NULL;
122 iwp->context = context;
123
124 name = g_strdup_printf("chardev-iowatch-%s", chr->label);
125 g_source_set_name((GSource *)iwp, name);
126 g_free(name);
127
128 g_source_attach(&iwp->parent, context);
129 g_source_unref(&iwp->parent);
130 return (GSource *)iwp;
131 }
132
io_remove_watch_poll(GSource * source)133 static void io_remove_watch_poll(GSource *source)
134 {
135 IOWatchPoll *iwp;
136
137 iwp = io_watch_poll_from_source(source);
138 g_source_destroy(&iwp->parent);
139 }
140
remove_fd_in_watch(Chardev * chr)141 void remove_fd_in_watch(Chardev *chr)
142 {
143 if (chr->gsource) {
144 io_remove_watch_poll(chr->gsource);
145 chr->gsource = NULL;
146 }
147 }
148
io_channel_send_full(QIOChannel * ioc,const void * buf,size_t len,int * fds,size_t nfds)149 int io_channel_send_full(QIOChannel *ioc,
150 const void *buf, size_t len,
151 int *fds, size_t nfds)
152 {
153 size_t offset = 0;
154
155 while (offset < len) {
156 ssize_t ret = 0;
157 struct iovec iov = { .iov_base = (char *)buf + offset,
158 .iov_len = len - offset };
159
160 ret = qio_channel_writev_full(
161 ioc, &iov, 1,
162 fds, nfds, 0, NULL);
163 if (ret == QIO_CHANNEL_ERR_BLOCK) {
164 if (offset) {
165 return offset;
166 }
167
168 errno = EAGAIN;
169 return -1;
170 } else if (ret < 0) {
171 errno = EINVAL;
172 return -1;
173 }
174
175 offset += ret;
176 }
177
178 return offset;
179 }
180
io_channel_send(QIOChannel * ioc,const void * buf,size_t len)181 int io_channel_send(QIOChannel *ioc, const void *buf, size_t len)
182 {
183 return io_channel_send_full(ioc, buf, len, NULL, 0);
184 }
185