quorum: Avoid bdrv_aio_writev() for rewrites
[qemu.git] / io / channel-buffer.c
1 /*
2 * QEMU I/O channels memory buffer driver
3 *
4 * Copyright (c) 2015 Red Hat, Inc.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 *
19 */
20
21 #include "qemu/osdep.h"
22 #include "io/channel-buffer.h"
23 #include "io/channel-watch.h"
24 #include "qemu/sockets.h"
25 #include "trace.h"
26
27 QIOChannelBuffer *
28 qio_channel_buffer_new(size_t capacity)
29 {
30 QIOChannelBuffer *ioc;
31
32 ioc = QIO_CHANNEL_BUFFER(object_new(TYPE_QIO_CHANNEL_BUFFER));
33
34 if (capacity) {
35 ioc->data = g_new0(uint8_t, capacity);
36 ioc->capacity = capacity;
37 }
38
39 return ioc;
40 }
41
42
43 static void qio_channel_buffer_finalize(Object *obj)
44 {
45 QIOChannelBuffer *ioc = QIO_CHANNEL_BUFFER(obj);
46 g_free(ioc->data);
47 ioc->capacity = ioc->usage = ioc->offset = 0;
48 }
49
50
51 static ssize_t qio_channel_buffer_readv(QIOChannel *ioc,
52 const struct iovec *iov,
53 size_t niov,
54 int **fds,
55 size_t *nfds,
56 Error **errp)
57 {
58 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
59 ssize_t ret = 0;
60 size_t i;
61
62 for (i = 0; i < niov; i++) {
63 size_t want = iov[i].iov_len;
64 if (bioc->offset >= bioc->usage) {
65 break;
66 }
67 if ((bioc->offset + want) > bioc->usage) {
68 want = bioc->usage - bioc->offset;
69 }
70 memcpy(iov[i].iov_base, bioc->data + bioc->offset, want);
71 ret += want;
72 bioc->offset += want;
73 }
74
75 return ret;
76 }
77
78 static ssize_t qio_channel_buffer_writev(QIOChannel *ioc,
79 const struct iovec *iov,
80 size_t niov,
81 int *fds,
82 size_t nfds,
83 Error **errp)
84 {
85 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
86 ssize_t ret = 0;
87 size_t i;
88 size_t towrite = 0;
89
90 for (i = 0; i < niov; i++) {
91 towrite += iov[i].iov_len;
92 }
93
94 if ((bioc->offset + towrite) > bioc->capacity) {
95 bioc->capacity = bioc->offset + towrite;
96 bioc->data = g_realloc(bioc->data, bioc->capacity);
97 }
98
99 if (bioc->offset > bioc->usage) {
100 memset(bioc->data, 0, bioc->offset - bioc->usage);
101 bioc->usage = bioc->offset;
102 }
103
104 for (i = 0; i < niov; i++) {
105 memcpy(bioc->data + bioc->usage,
106 iov[i].iov_base,
107 iov[i].iov_len);
108 bioc->usage += iov[i].iov_len;
109 bioc->offset += iov[i].iov_len;
110 ret += iov[i].iov_len;
111 }
112
113 return ret;
114 }
115
116 static int qio_channel_buffer_set_blocking(QIOChannel *ioc G_GNUC_UNUSED,
117 bool enabled G_GNUC_UNUSED,
118 Error **errp G_GNUC_UNUSED)
119 {
120 return 0;
121 }
122
123
124 static off_t qio_channel_buffer_seek(QIOChannel *ioc,
125 off_t offset,
126 int whence,
127 Error **errp)
128 {
129 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
130
131 bioc->offset = offset;
132
133 return offset;
134 }
135
136
137 static int qio_channel_buffer_close(QIOChannel *ioc,
138 Error **errp)
139 {
140 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
141
142 g_free(bioc->data);
143 bioc->data = NULL;
144 bioc->capacity = bioc->usage = bioc->offset = 0;
145
146 return 0;
147 }
148
149
150 typedef struct QIOChannelBufferSource QIOChannelBufferSource;
151 struct QIOChannelBufferSource {
152 GSource parent;
153 QIOChannelBuffer *bioc;
154 GIOCondition condition;
155 };
156
157 static gboolean
158 qio_channel_buffer_source_prepare(GSource *source,
159 gint *timeout)
160 {
161 QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
162
163 *timeout = -1;
164
165 return (G_IO_IN | G_IO_OUT) & bsource->condition;
166 }
167
168 static gboolean
169 qio_channel_buffer_source_check(GSource *source)
170 {
171 QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
172
173 return (G_IO_IN | G_IO_OUT) & bsource->condition;
174 }
175
176 static gboolean
177 qio_channel_buffer_source_dispatch(GSource *source,
178 GSourceFunc callback,
179 gpointer user_data)
180 {
181 QIOChannelFunc func = (QIOChannelFunc)callback;
182 QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source;
183
184 return (*func)(QIO_CHANNEL(bsource->bioc),
185 ((G_IO_IN | G_IO_OUT) & bsource->condition),
186 user_data);
187 }
188
189 static void
190 qio_channel_buffer_source_finalize(GSource *source)
191 {
192 QIOChannelBufferSource *ssource = (QIOChannelBufferSource *)source;
193
194 object_unref(OBJECT(ssource->bioc));
195 }
196
197 GSourceFuncs qio_channel_buffer_source_funcs = {
198 qio_channel_buffer_source_prepare,
199 qio_channel_buffer_source_check,
200 qio_channel_buffer_source_dispatch,
201 qio_channel_buffer_source_finalize
202 };
203
204 static GSource *qio_channel_buffer_create_watch(QIOChannel *ioc,
205 GIOCondition condition)
206 {
207 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc);
208 QIOChannelBufferSource *ssource;
209 GSource *source;
210
211 source = g_source_new(&qio_channel_buffer_source_funcs,
212 sizeof(QIOChannelBufferSource));
213 ssource = (QIOChannelBufferSource *)source;
214
215 ssource->bioc = bioc;
216 object_ref(OBJECT(bioc));
217
218 ssource->condition = condition;
219
220 return source;
221 }
222
223
224 static void qio_channel_buffer_class_init(ObjectClass *klass,
225 void *class_data G_GNUC_UNUSED)
226 {
227 QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
228
229 ioc_klass->io_writev = qio_channel_buffer_writev;
230 ioc_klass->io_readv = qio_channel_buffer_readv;
231 ioc_klass->io_set_blocking = qio_channel_buffer_set_blocking;
232 ioc_klass->io_seek = qio_channel_buffer_seek;
233 ioc_klass->io_close = qio_channel_buffer_close;
234 ioc_klass->io_create_watch = qio_channel_buffer_create_watch;
235 }
236
237 static const TypeInfo qio_channel_buffer_info = {
238 .parent = TYPE_QIO_CHANNEL,
239 .name = TYPE_QIO_CHANNEL_BUFFER,
240 .instance_size = sizeof(QIOChannelBuffer),
241 .instance_finalize = qio_channel_buffer_finalize,
242 .class_init = qio_channel_buffer_class_init,
243 };
244
245 static void qio_channel_buffer_register_types(void)
246 {
247 type_register_static(&qio_channel_buffer_info);
248 }
249
250 type_init(qio_channel_buffer_register_types);