summaryrefslogtreecommitdiffstats
path: root/chardev/char-ringbuf.c
blob: 87832e27920ec78cab71db564b38f7fccaf3f19e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
/*
 * 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/option.h"

/* Ring buffer chardev */

typedef struct {
    Chardev parent;
    size_t size;
    size_t prod;
    size_t cons;
    uint8_t *cbuf;
} RingBufChardev;

#define RINGBUF_CHARDEV(obj)                                    \
    OBJECT_CHECK(RingBufChardev, (obj), 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);