slirp: VMStatify sbuf
[qemu.git] / chardev / char-io.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 #include "qemu/osdep.h"
25 #include "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 if (now_active) {
55 iwp->src = qio_channel_create_watch(
56 iwp->ioc, G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
57 g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
58 g_source_attach(iwp->src, iwp->context);
59 } else {
60 g_source_destroy(iwp->src);
61 g_source_unref(iwp->src);
62 iwp->src = NULL;
63 }
64 return FALSE;
65 }
66
67 static gboolean io_watch_poll_check(GSource *source)
68 {
69 return FALSE;
70 }
71
72 static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback,
73 gpointer user_data)
74 {
75 abort();
76 }
77
78 static void io_watch_poll_finalize(GSource *source)
79 {
80 /* Due to a glib bug, removing the last reference to a source
81 * inside a finalize callback causes recursive locking (and a
82 * deadlock). This is not a problem inside other callbacks,
83 * including dispatch callbacks, so we call io_remove_watch_poll
84 * to remove this source. At this point, iwp->src must
85 * be NULL, or we would leak it.
86 *
87 * This would be solved much more elegantly by child sources,
88 * but we support older glib versions that do not have them.
89 */
90 IOWatchPoll *iwp = io_watch_poll_from_source(source);
91 assert(iwp->src == NULL);
92 }
93
94 static GSourceFuncs io_watch_poll_funcs = {
95 .prepare = io_watch_poll_prepare,
96 .check = io_watch_poll_check,
97 .dispatch = io_watch_poll_dispatch,
98 .finalize = io_watch_poll_finalize,
99 };
100
101 guint io_add_watch_poll(Chardev *chr,
102 QIOChannel *ioc,
103 IOCanReadHandler *fd_can_read,
104 QIOChannelFunc fd_read,
105 gpointer user_data,
106 GMainContext *context)
107 {
108 IOWatchPoll *iwp;
109 int tag;
110 char *name;
111
112 iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
113 sizeof(IOWatchPoll));
114 iwp->fd_can_read = fd_can_read;
115 iwp->opaque = user_data;
116 iwp->ioc = ioc;
117 iwp->fd_read = (GSourceFunc) fd_read;
118 iwp->src = NULL;
119 iwp->context = context;
120
121 name = g_strdup_printf("chardev-iowatch-%s", chr->label);
122 g_source_set_name((GSource *)iwp, name);
123 g_free(name);
124
125 tag = g_source_attach(&iwp->parent, context);
126 g_source_unref(&iwp->parent);
127 return tag;
128 }
129
130 static void io_remove_watch_poll(guint tag, GMainContext *context)
131 {
132 GSource *source;
133 IOWatchPoll *iwp;
134
135 g_return_if_fail(tag > 0);
136
137 source = g_main_context_find_source_by_id(context, tag);
138 g_return_if_fail(source != NULL);
139
140 iwp = io_watch_poll_from_source(source);
141 if (iwp->src) {
142 g_source_destroy(iwp->src);
143 g_source_unref(iwp->src);
144 iwp->src = NULL;
145 }
146 g_source_destroy(&iwp->parent);
147 }
148
149 void remove_fd_in_watch(Chardev *chr, GMainContext *context)
150 {
151 if (chr->fd_in_tag) {
152 io_remove_watch_poll(chr->fd_in_tag, context);
153 chr->fd_in_tag = 0;
154 }
155 }
156
157 int io_channel_send_full(QIOChannel *ioc,
158 const void *buf, size_t len,
159 int *fds, size_t nfds)
160 {
161 size_t offset = 0;
162
163 while (offset < len) {
164 ssize_t ret = 0;
165 struct iovec iov = { .iov_base = (char *)buf + offset,
166 .iov_len = len - offset };
167
168 ret = qio_channel_writev_full(
169 ioc, &iov, 1,
170 fds, nfds, NULL);
171 if (ret == QIO_CHANNEL_ERR_BLOCK) {
172 if (offset) {
173 return offset;
174 }
175
176 errno = EAGAIN;
177 return -1;
178 } else if (ret < 0) {
179 errno = EINVAL;
180 return -1;
181 }
182
183 offset += ret;
184 }
185
186 return offset;
187 }
188
189 int io_channel_send(QIOChannel *ioc, const void *buf, size_t len)
190 {
191 return io_channel_send_full(ioc, buf, len, NULL, 0);
192 }