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); 251