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