qemu

char-ringbuf.c (6996B)

---

 /*
  * QEMU System Emulator
  *
  * Copyright (c) 2003-2008 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 
 #include "qemu/osdep.h"
 #include "chardev/char.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-char.h"
 #include "qemu/base64.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
 #include "qom/object.h"
 
 /* Ring buffer chardev */
 
 struct RingBufChardev {
     Chardev parent;
     size_t size;
     size_t prod;
     size_t cons;
     uint8_t *cbuf;
 };
 typedef struct RingBufChardev RingBufChardev;
 
 DECLARE_INSTANCE_CHECKER(RingBufChardev, RINGBUF_CHARDEV,
                          TYPE_CHARDEV_RINGBUF)
 
 static size_t ringbuf_count(const Chardev *chr)
 {
     const RingBufChardev *d = RINGBUF_CHARDEV(chr);
 
     return d->prod - d->cons;
 }
 
 static int ringbuf_chr_write(Chardev *chr, const uint8_t *buf, int len)
 {
     RingBufChardev *d = RINGBUF_CHARDEV(chr);
     int i;
 
     if (!buf || (len < 0)) {
         return -1;
     }
 
     for (i = 0; i < len; i++) {
         d->cbuf[d->prod++ & (d->size - 1)] = buf[i];
         if (d->prod - d->cons > d->size) {
             d->cons = d->prod - d->size;
         }
     }
 
     return len;
 }
 
 static int ringbuf_chr_read(Chardev *chr, uint8_t *buf, int len)
 {
     RingBufChardev *d = RINGBUF_CHARDEV(chr);
     int i;
 
     qemu_mutex_lock(&chr->chr_write_lock);
     for (i = 0; i < len && d->cons != d->prod; i++) {
         buf[i] = d->cbuf[d->cons++ & (d->size - 1)];
     }
     qemu_mutex_unlock(&chr->chr_write_lock);
 
     return i;
 }
 
 static void char_ringbuf_finalize(Object *obj)
 {
     RingBufChardev *d = RINGBUF_CHARDEV(obj);
 
     g_free(d->cbuf);
 }
 
 static void qemu_chr_open_ringbuf(Chardev *chr,
                                   ChardevBackend *backend,
                                   bool *be_opened,
                                   Error **errp)
 {
     ChardevRingbuf *opts = backend->u.ringbuf.data;
     RingBufChardev *d = RINGBUF_CHARDEV(chr);
 
     d->size = opts->has_size ? opts->size : 65536;
 
     /* The size must be power of 2 */
     if (d->size & (d->size - 1)) {
         error_setg(errp, "size of ringbuf chardev must be power of two");
         return;
     }
 
     d->prod = 0;
     d->cons = 0;
     d->cbuf = g_malloc0(d->size);
 }
 
 void qmp_ringbuf_write(const char *device, const char *data,
                        bool has_format, enum DataFormat format,
                        Error **errp)
 {
     Chardev *chr;
     const uint8_t *write_data;
     int ret;
     gsize write_count;
 
     chr = qemu_chr_find(device);
     if (!chr) {
         error_setg(errp, "Device '%s' not found", device);
         return;
     }
 
     if (!CHARDEV_IS_RINGBUF(chr)) {
         error_setg(errp, "%s is not a ringbuf device", device);
         return;
     }
 
     if (has_format && (format == DATA_FORMAT_BASE64)) {
         write_data = qbase64_decode(data, -1,
                                     &write_count,
                                     errp);
         if (!write_data) {
             return;
         }
     } else {
         write_data = (uint8_t *)data;
         write_count = strlen(data);
     }
 
     ret = ringbuf_chr_write(chr, write_data, write_count);
 
     if (write_data != (uint8_t *)data) {
         g_free((void *)write_data);
     }
 
     if (ret < 0) {
         error_setg(errp, "Failed to write to device %s", device);
         return;
     }
 }
 
 char *qmp_ringbuf_read(const char *device, int64_t size,
                        bool has_format, enum DataFormat format,
                        Error **errp)
 {
     Chardev *chr;
     uint8_t *read_data;
     size_t count;
     char *data;
 
     chr = qemu_chr_find(device);
     if (!chr) {
         error_setg(errp, "Device '%s' not found", device);
         return NULL;
     }
 
     if (!CHARDEV_IS_RINGBUF(chr)) {
         error_setg(errp, "%s is not a ringbuf device", device);
         return NULL;
     }
 
     if (size <= 0) {
         error_setg(errp, "size must be greater than zero");
         return NULL;
     }
 
     count = ringbuf_count(chr);
     size = size > count ? count : size;
     read_data = g_malloc(size + 1);
 
     ringbuf_chr_read(chr, read_data, size);
 
     if (has_format && (format == DATA_FORMAT_BASE64)) {
         data = g_base64_encode(read_data, size);
         g_free(read_data);
     } else {
         /*
          * FIXME should read only complete, valid UTF-8 characters up
          * to @size bytes.  Invalid sequences should be replaced by a
          * suitable replacement character.  Except when (and only
          * when) ring buffer lost characters since last read, initial
          * continuation characters should be dropped.
          */
         read_data[size] = 0;
         data = (char *)read_data;
     }
 
     return data;
 }
 
 static void qemu_chr_parse_ringbuf(QemuOpts *opts, ChardevBackend *backend,
                                    Error **errp)
 {
     int val;
     ChardevRingbuf *ringbuf;
 
     backend->type = CHARDEV_BACKEND_KIND_RINGBUF;
     ringbuf = backend->u.ringbuf.data = g_new0(ChardevRingbuf, 1);
     qemu_chr_parse_common(opts, qapi_ChardevRingbuf_base(ringbuf));
 
     val = qemu_opt_get_size(opts, "size", 0);
     if (val != 0) {
         ringbuf->has_size = true;
         ringbuf->size = val;
     }
 }
 
 static void char_ringbuf_class_init(ObjectClass *oc, void *data)
 {
     ChardevClass *cc = CHARDEV_CLASS(oc);
 
     cc->parse = qemu_chr_parse_ringbuf;
     cc->open = qemu_chr_open_ringbuf;
     cc->chr_write = ringbuf_chr_write;
 }
 
 static const TypeInfo char_ringbuf_type_info = {
     .name = TYPE_CHARDEV_RINGBUF,
     .parent = TYPE_CHARDEV,
     .class_init = char_ringbuf_class_init,
     .instance_size = sizeof(RingBufChardev),
     .instance_finalize = char_ringbuf_finalize,
 };
 
 /* Bug-compatibility: */
 static const TypeInfo char_memory_type_info = {
     .name = TYPE_CHARDEV_MEMORY,
     .parent = TYPE_CHARDEV_RINGBUF,
 };
 
 static void register_types(void)
 {
     type_register_static(&char_ringbuf_type_info);
     type_register_static(&char_memory_type_info);
 }
 
 type_init(register_types);