chardev/char-ringbuf.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
  25 #include "qemu/osdep.h"
  26 #include "chardev/char.h"
  27 #include "qapi/error.h"
  28 #include "qapi/qapi-commands-char.h"
  29 #include "qemu/base64.h"
  30 #include "qemu/module.h"
  31 #include "qemu/option.h"
  32
  33 /* Ring buffer chardev */
  34
  35 typedef struct {
  36     Chardev parent;
  37     size_t size;
  38     size_t prod;
  39     size_t cons;
  40     uint8_t *cbuf;
  41 } RingBufChardev;
  42
  43 #define RINGBUF_CHARDEV(obj)                                    \
  44     OBJECT_CHECK(RingBufChardev, (obj), TYPE_CHARDEV_RINGBUF)
  45
  46 static size_t ringbuf_count(const Chardev *chr)
  47 {
  48     const RingBufChardev *d = RINGBUF_CHARDEV(chr);
  49
  50     return d->prod - d->cons;
  51 }
  52
  53 static int ringbuf_chr_write(Chardev *chr, const uint8_t *buf, int len)
  54 {
  55     RingBufChardev *d = RINGBUF_CHARDEV(chr);
  56     int i;
  57
  58     if (!buf || (len < 0)) {
  59         return -1;
  60     }
  61
  62     for (i = 0; i < len; i++) {
  63         d->cbuf[d->prod++ & (d->size - 1)] = buf[i];
  64         if (d->prod - d->cons > d->size) {
  65             d->cons = d->prod - d->size;
  66         }
  67     }
  68
  69     return len;
  70 }
  71
  72 static int ringbuf_chr_read(Chardev *chr, uint8_t *buf, int len)
  73 {
  74     RingBufChardev *d = RINGBUF_CHARDEV(chr);
  75     int i;
  76
  77     qemu_mutex_lock(&chr->chr_write_lock);
  78     for (i = 0; i < len && d->cons != d->prod; i++) {
  79         buf[i] = d->cbuf[d->cons++ & (d->size - 1)];
  80     }
  81     qemu_mutex_unlock(&chr->chr_write_lock);
  82
  83     return i;
  84 }
  85
  86 static void char_ringbuf_finalize(Object *obj)
  87 {
  88     RingBufChardev *d = RINGBUF_CHARDEV(obj);
  89
  90     g_free(d->cbuf);
  91 }
  92
  93 static void qemu_chr_open_ringbuf(Chardev *chr,
  94                                   ChardevBackend *backend,
  95                                   bool *be_opened,
  96                                   Error **errp)
  97 {
  98     ChardevRingbuf *opts = backend->u.ringbuf.data;
  99     RingBufChardev *d = RINGBUF_CHARDEV(chr);
 100
 101     d->size = opts->has_size ? opts->size : 65536;
 102
 103     /* The size must be power of 2 */
 104     if (d->size & (d->size - 1)) {
 105         error_setg(errp, "size of ringbuf chardev must be power of two");
 106         return;
 107     }
 108
 109     d->prod = 0;
 110     d->cons = 0;
 111     d->cbuf = g_malloc0(d->size);
 112 }
 113
 114 void qmp_ringbuf_write(const char *device, const char *data,
 115                        bool has_format, enum DataFormat format,
 116                        Error **errp)
 117 {
 118     Chardev *chr;
 119     const uint8_t *write_data;
 120     int ret;
 121     gsize write_count;
 122
 123     chr = qemu_chr_find(device);
 124     if (!chr) {
 125         error_setg(errp, "Device '%s' not found", device);
 126         return;
 127     }
 128
 129     if (!CHARDEV_IS_RINGBUF(chr)) {
 130         error_setg(errp, "%s is not a ringbuf device", device);
 131         return;
 132     }
 133
 134     if (has_format && (format == DATA_FORMAT_BASE64)) {
 135         write_data = qbase64_decode(data, -1,
 136                                     &write_count,
 137                                     errp);
 138         if (!write_data) {
 139             return;
 140         }
 141     } else {
 142         write_data = (uint8_t *)data;
 143         write_count = strlen(data);
 144     }
 145
 146     ret = ringbuf_chr_write(chr, write_data, write_count);
 147
 148     if (write_data != (uint8_t *)data) {
 149         g_free((void *)write_data);
 150     }
 151
 152     if (ret < 0) {
 153         error_setg(errp, "Failed to write to device %s", device);
 154         return;
 155     }
 156 }
 157
 158 char *qmp_ringbuf_read(const char *device, int64_t size,
 159                        bool has_format, enum DataFormat format,
 160                        Error **errp)
 161 {
 162     Chardev *chr;
 163     uint8_t *read_data;
 164     size_t count;
 165     char *data;
 166
 167     chr = qemu_chr_find(device);
 168     if (!chr) {
 169         error_setg(errp, "Device '%s' not found", device);
 170         return NULL;
 171     }
 172
 173     if (!CHARDEV_IS_RINGBUF(chr)) {
 174         error_setg(errp, "%s is not a ringbuf device", device);
 175         return NULL;
 176     }
 177
 178     if (size <= 0) {
 179         error_setg(errp, "size must be greater than zero");
 180         return NULL;
 181     }
 182
 183     count = ringbuf_count(chr);
 184     size = size > count ? count : size;
 185     read_data = g_malloc(size + 1);
 186
 187     ringbuf_chr_read(chr, read_data, size);
 188
 189     if (has_format && (format == DATA_FORMAT_BASE64)) {
 190         data = g_base64_encode(read_data, size);
 191         g_free(read_data);
 192     } else {
 193         /*
 194          * FIXME should read only complete, valid UTF-8 characters up
 195          * to @size bytes.  Invalid sequences should be replaced by a
 196          * suitable replacement character.  Except when (and only
 197          * when) ring buffer lost characters since last read, initial
 198          * continuation characters should be dropped.
 199          */
 200         read_data[size] = 0;
 201         data = (char *)read_data;
 202     }
 203
 204     return data;
 205 }
 206
 207 static void qemu_chr_parse_ringbuf(QemuOpts *opts, ChardevBackend *backend,
 208                                    Error **errp)
 209 {
 210     int val;
 211     ChardevRingbuf *ringbuf;
 212
 213     backend->type = CHARDEV_BACKEND_KIND_RINGBUF;
 214     ringbuf = backend->u.ringbuf.data = g_new0(ChardevRingbuf, 1);
 215     qemu_chr_parse_common(opts, qapi_ChardevRingbuf_base(ringbuf));
 216
 217     val = qemu_opt_get_size(opts, "size", 0);
 218     if (val != 0) {
 219         ringbuf->has_size = true;
 220         ringbuf->size = val;
 221     }
 222 }
 223
 224 static void char_ringbuf_class_init(ObjectClass *oc, void *data)
 225 {
 226     ChardevClass *cc = CHARDEV_CLASS(oc);
 227
 228     cc->parse = qemu_chr_parse_ringbuf;
 229     cc->open = qemu_chr_open_ringbuf;
 230     cc->chr_write = ringbuf_chr_write;
 231 }
 232
 233 static const TypeInfo char_ringbuf_type_info = {
 234     .name = TYPE_CHARDEV_RINGBUF,
 235     .parent = TYPE_CHARDEV,
 236     .class_init = char_ringbuf_class_init,
 237     .instance_size = sizeof(RingBufChardev),
 238     .instance_finalize = char_ringbuf_finalize,
 239 };
 240
 241 /* Bug-compatibility: */
 242 static const TypeInfo char_memory_type_info = {
 243     .name = TYPE_CHARDEV_MEMORY,
 244     .parent = TYPE_CHARDEV_RINGBUF,
 245 };
 246
 247 static void register_types(void)
 248 {
 249     type_register_static(&char_ringbuf_type_info);
 250     type_register_static(&char_memory_type_info);
 251 }
 252
 253 type_init(register_types);