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