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 #include "qom/object.h"
  33
  34 /* Ring buffer chardev */
  35
  36 struct RingBufChardev {
  37     Chardev parent;
  38     size_t size;
  39     size_t prod;
  40     size_t cons;
  41     uint8_t *cbuf;
  42 };
  43 typedef struct RingBufChardev RingBufChardev;
  44
  45 DECLARE_INSTANCE_CHECKER(RingBufChardev, RINGBUF_CHARDEV,
  46                          TYPE_CHARDEV_RINGBUF)
  47
  48 static size_t ringbuf_count(const Chardev *chr)
  49 {
  50     const RingBufChardev *d = RINGBUF_CHARDEV(chr);
  51
  52     return d->prod - d->cons;
  53 }
  54
  55 static int ringbuf_chr_write(Chardev *chr, const uint8_t *buf, int len)
  56 {
  57     RingBufChardev *d = RINGBUF_CHARDEV(chr);
  58     int i;
  59
  60     if (!buf || (len < 0)) {
  61         return -1;
  62     }
  63
  64     for (i = 0; i < len; i++) {
  65         d->cbuf[d->prod++ & (d->size - 1)] = buf[i];
  66         if (d->prod - d->cons > d->size) {
  67             d->cons = d->prod - d->size;
  68         }
  69     }
  70
  71     return len;
  72 }
  73
  74 static int ringbuf_chr_read(Chardev *chr, uint8_t *buf, int len)
  75 {
  76     RingBufChardev *d = RINGBUF_CHARDEV(chr);
  77     int i;
  78
  79     qemu_mutex_lock(&chr->chr_write_lock);
  80     for (i = 0; i < len && d->cons != d->prod; i++) {
  81         buf[i] = d->cbuf[d->cons++ & (d->size - 1)];
  82     }
  83     qemu_mutex_unlock(&chr->chr_write_lock);
  84
  85     return i;
  86 }
  87
  88 static void char_ringbuf_finalize(Object *obj)
  89 {
  90     RingBufChardev *d = RINGBUF_CHARDEV(obj);
  91
  92     g_free(d->cbuf);
  93 }
  94
  95 static void qemu_chr_open_ringbuf(Chardev *chr,
  96                                   ChardevBackend *backend,
  97                                   bool *be_opened,
  98                                   Error **errp)
  99 {
 100     ChardevRingbuf *opts = backend->u.ringbuf.data;
 101     RingBufChardev *d = RINGBUF_CHARDEV(chr);
 102
 103     d->size = opts->has_size ? opts->size : 65536;
 104
 105     /* The size must be power of 2 */
 106     if (d->size & (d->size - 1)) {
 107         error_setg(errp, "size of ringbuf chardev must be power of two");
 108         return;
 109     }
 110
 111     d->prod = 0;
 112     d->cons = 0;
 113     d->cbuf = g_malloc0(d->size);
 114 }
 115
 116 void qmp_ringbuf_write(const char *device, const char *data,
 117                        bool has_format, enum DataFormat format,
 118                        Error **errp)
 119 {
 120     Chardev *chr;
 121     const uint8_t *write_data;
 122     int ret;
 123     gsize write_count;
 124
 125     chr = qemu_chr_find(device);
 126     if (!chr) {
 127         error_setg(errp, "Device '%s' not found", device);
 128         return;
 129     }
 130
 131     if (!CHARDEV_IS_RINGBUF(chr)) {
 132         error_setg(errp, "%s is not a ringbuf device", device);
 133         return;
 134     }
 135
 136     if (has_format && (format == DATA_FORMAT_BASE64)) {
 137         write_data = qbase64_decode(data, -1,
 138                                     &write_count,
 139                                     errp);
 140         if (!write_data) {
 141             return;
 142         }
 143     } else {
 144         write_data = (uint8_t *)data;
 145         write_count = strlen(data);
 146     }
 147
 148     ret = ringbuf_chr_write(chr, write_data, write_count);
 149
 150     if (write_data != (uint8_t *)data) {
 151         g_free((void *)write_data);
 152     }
 153
 154     if (ret < 0) {
 155         error_setg(errp, "Failed to write to device %s", device);
 156         return;
 157     }
 158 }
 159
 160 char *qmp_ringbuf_read(const char *device, int64_t size,
 161                        bool has_format, enum DataFormat format,
 162                        Error **errp)
 163 {
 164     Chardev *chr;
 165     uint8_t *read_data;
 166     size_t count;
 167     char *data;
 168
 169     chr = qemu_chr_find(device);
 170     if (!chr) {
 171         error_setg(errp, "Device '%s' not found", device);
 172         return NULL;
 173     }
 174
 175     if (!CHARDEV_IS_RINGBUF(chr)) {
 176         error_setg(errp, "%s is not a ringbuf device", device);
 177         return NULL;
 178     }
 179
 180     if (size <= 0) {
 181         error_setg(errp, "size must be greater than zero");
 182         return NULL;
 183     }
 184
 185     count = ringbuf_count(chr);
 186     size = size > count ? count : size;
 187     read_data = g_malloc(size + 1);
 188
 189     ringbuf_chr_read(chr, read_data, size);
 190
 191     if (has_format && (format == DATA_FORMAT_BASE64)) {
 192         data = g_base64_encode(read_data, size);
 193         g_free(read_data);
 194     } else {
 195         /*
 196          * FIXME should read only complete, valid UTF-8 characters up
 197          * to @size bytes.  Invalid sequences should be replaced by a
 198          * suitable replacement character.  Except when (and only
 199          * when) ring buffer lost characters since last read, initial
 200          * continuation characters should be dropped.
 201          */
 202         read_data[size] = 0;
 203         data = (char *)read_data;
 204     }
 205
 206     return data;
 207 }
 208
 209 static void qemu_chr_parse_ringbuf(QemuOpts *opts, ChardevBackend *backend,
 210                                    Error **errp)
 211 {
 212     int val;
 213     ChardevRingbuf *ringbuf;
 214
 215     backend->type = CHARDEV_BACKEND_KIND_RINGBUF;
 216     ringbuf = backend->u.ringbuf.data = g_new0(ChardevRingbuf, 1);
 217     qemu_chr_parse_common(opts, qapi_ChardevRingbuf_base(ringbuf));
 218
 219     val = qemu_opt_get_size(opts, "size", 0);
 220     if (val != 0) {
 221         ringbuf->has_size = true;
 222         ringbuf->size = val;
 223     }
 224 }
 225
 226 static void char_ringbuf_class_init(ObjectClass *oc, void *data)
 227 {
 228     ChardevClass *cc = CHARDEV_CLASS(oc);
 229
 230     cc->parse = qemu_chr_parse_ringbuf;
 231     cc->open = qemu_chr_open_ringbuf;
 232     cc->chr_write = ringbuf_chr_write;
 233 }
 234
 235 static const TypeInfo char_ringbuf_type_info = {
 236     .name = TYPE_CHARDEV_RINGBUF,
 237     .parent = TYPE_CHARDEV,
 238     .class_init = char_ringbuf_class_init,
 239     .instance_size = sizeof(RingBufChardev),
 240     .instance_finalize = char_ringbuf_finalize,
 241 };
 242
 243 /* Bug-compatibility: */
 244 static const TypeInfo char_memory_type_info = {
 245     .name = TYPE_CHARDEV_MEMORY,
 246     .parent = TYPE_CHARDEV_RINGBUF,
 247 };
 248
 249 static void register_types(void)
 250 {
 251     type_register_static(&char_ringbuf_type_info);
 252     type_register_static(&char_memory_type_info);
 253 }
 254
 255 type_init(register_types);