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 2.1 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/module.h" 25 #include "qemu/sockets.h" 26 #include "trace.h" 27 28 QIOChannelBuffer * 29 qio_channel_buffer_new(size_t capacity) 30 { 31 QIOChannelBuffer *ioc; 32 33 ioc = QIO_CHANNEL_BUFFER(object_new(TYPE_QIO_CHANNEL_BUFFER)); 34 35 if (capacity) { 36 ioc->data = g_new0(uint8_t, capacity); 37 ioc->capacity = capacity; 38 } 39 40 return ioc; 41 } 42 43 44 static void qio_channel_buffer_finalize(Object *obj) 45 { 46 QIOChannelBuffer *ioc = QIO_CHANNEL_BUFFER(obj); 47 g_free(ioc->data); 48 ioc->capacity = ioc->usage = ioc->offset = 0; 49 } 50 51 52 static ssize_t qio_channel_buffer_readv(QIOChannel *ioc, 53 const struct iovec *iov, 54 size_t niov, 55 int **fds, 56 size_t *nfds, 57 Error **errp) 58 { 59 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc); 60 ssize_t ret = 0; 61 size_t i; 62 63 for (i = 0; i < niov; i++) { 64 size_t want = iov[i].iov_len; 65 if (bioc->offset >= bioc->usage) { 66 break; 67 } 68 if ((bioc->offset + want) > bioc->usage) { 69 want = bioc->usage - bioc->offset; 70 } 71 memcpy(iov[i].iov_base, bioc->data + bioc->offset, want); 72 ret += want; 73 bioc->offset += want; 74 } 75 76 return ret; 77 } 78 79 static ssize_t qio_channel_buffer_writev(QIOChannel *ioc, 80 const struct iovec *iov, 81 size_t niov, 82 int *fds, 83 size_t nfds, 84 Error **errp) 85 { 86 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc); 87 ssize_t ret = 0; 88 size_t i; 89 size_t towrite = 0; 90 91 for (i = 0; i < niov; i++) { 92 towrite += iov[i].iov_len; 93 } 94 95 if ((bioc->offset + towrite) > bioc->capacity) { 96 bioc->capacity = bioc->offset + towrite; 97 bioc->data = g_realloc(bioc->data, bioc->capacity); 98 } 99 100 if (bioc->offset > bioc->usage) { 101 memset(bioc->data, 0, bioc->offset - bioc->usage); 102 bioc->usage = bioc->offset; 103 } 104 105 for (i = 0; i < niov; i++) { 106 memcpy(bioc->data + bioc->usage, 107 iov[i].iov_base, 108 iov[i].iov_len); 109 bioc->usage += iov[i].iov_len; 110 bioc->offset += iov[i].iov_len; 111 ret += iov[i].iov_len; 112 } 113 114 return ret; 115 } 116 117 static int qio_channel_buffer_set_blocking(QIOChannel *ioc G_GNUC_UNUSED, 118 bool enabled G_GNUC_UNUSED, 119 Error **errp G_GNUC_UNUSED) 120 { 121 return 0; 122 } 123 124 125 static off_t qio_channel_buffer_seek(QIOChannel *ioc, 126 off_t offset, 127 int whence, 128 Error **errp) 129 { 130 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc); 131 132 bioc->offset = offset; 133 134 return offset; 135 } 136 137 138 static int qio_channel_buffer_close(QIOChannel *ioc, 139 Error **errp) 140 { 141 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc); 142 143 g_free(bioc->data); 144 bioc->data = NULL; 145 bioc->capacity = bioc->usage = bioc->offset = 0; 146 147 return 0; 148 } 149 150 151 typedef struct QIOChannelBufferSource QIOChannelBufferSource; 152 struct QIOChannelBufferSource { 153 GSource parent; 154 QIOChannelBuffer *bioc; 155 GIOCondition condition; 156 }; 157 158 static gboolean 159 qio_channel_buffer_source_prepare(GSource *source, 160 gint *timeout) 161 { 162 QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source; 163 164 *timeout = -1; 165 166 return (G_IO_IN | G_IO_OUT) & bsource->condition; 167 } 168 169 static gboolean 170 qio_channel_buffer_source_check(GSource *source) 171 { 172 QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source; 173 174 return (G_IO_IN | G_IO_OUT) & bsource->condition; 175 } 176 177 static gboolean 178 qio_channel_buffer_source_dispatch(GSource *source, 179 GSourceFunc callback, 180 gpointer user_data) 181 { 182 QIOChannelFunc func = (QIOChannelFunc)callback; 183 QIOChannelBufferSource *bsource = (QIOChannelBufferSource *)source; 184 185 return (*func)(QIO_CHANNEL(bsource->bioc), 186 ((G_IO_IN | G_IO_OUT) & bsource->condition), 187 user_data); 188 } 189 190 static void 191 qio_channel_buffer_source_finalize(GSource *source) 192 { 193 QIOChannelBufferSource *ssource = (QIOChannelBufferSource *)source; 194 195 object_unref(OBJECT(ssource->bioc)); 196 } 197 198 GSourceFuncs qio_channel_buffer_source_funcs = { 199 qio_channel_buffer_source_prepare, 200 qio_channel_buffer_source_check, 201 qio_channel_buffer_source_dispatch, 202 qio_channel_buffer_source_finalize 203 }; 204 205 static GSource *qio_channel_buffer_create_watch(QIOChannel *ioc, 206 GIOCondition condition) 207 { 208 QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc); 209 QIOChannelBufferSource *ssource; 210 GSource *source; 211 212 source = g_source_new(&qio_channel_buffer_source_funcs, 213 sizeof(QIOChannelBufferSource)); 214 ssource = (QIOChannelBufferSource *)source; 215 216 ssource->bioc = bioc; 217 object_ref(OBJECT(bioc)); 218 219 ssource->condition = condition; 220 221 return source; 222 } 223 224 225 static void qio_channel_buffer_class_init(ObjectClass *klass, 226 void *class_data G_GNUC_UNUSED) 227 { 228 QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); 229 230 ioc_klass->io_writev = qio_channel_buffer_writev; 231 ioc_klass->io_readv = qio_channel_buffer_readv; 232 ioc_klass->io_set_blocking = qio_channel_buffer_set_blocking; 233 ioc_klass->io_seek = qio_channel_buffer_seek; 234 ioc_klass->io_close = qio_channel_buffer_close; 235 ioc_klass->io_create_watch = qio_channel_buffer_create_watch; 236 } 237 238 static const TypeInfo qio_channel_buffer_info = { 239 .parent = TYPE_QIO_CHANNEL, 240 .name = TYPE_QIO_CHANNEL_BUFFER, 241 .instance_size = sizeof(QIOChannelBuffer), 242 .instance_finalize = qio_channel_buffer_finalize, 243 .class_init = qio_channel_buffer_class_init, 244 }; 245 246 static void qio_channel_buffer_register_types(void) 247 { 248 type_register_static(&qio_channel_buffer_info); 249 } 250 251 type_init(qio_channel_buffer_register_types); 252