2 * QEMU buffered QEMUFile
4 * Copyright IBM, Corp. 2008
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
14 #include "qemu-common.h"
16 #include "qemu-timer.h"
18 #include "qemu-char.h"
19 #include "buffered_file.h"
21 //#define DEBUG_BUFFERED_FILE
23 typedef struct QEMUFileBuffered
25 BufferedPutFunc *put_buffer;
26 BufferedPutReadyFunc *put_ready;
27 BufferedWaitForUnfreezeFunc *wait_for_unfreeze;
28 BufferedCloseFunc *close;
37 size_t buffer_capacity;
41 #ifdef DEBUG_BUFFERED_FILE
42 #define DPRINTF(fmt, ...) \
43 do { printf("buffered-file: " fmt, ## __VA_ARGS__); } while (0)
45 #define DPRINTF(fmt, ...) \
49 static void buffered_append(QEMUFileBuffered *s,
50 const uint8_t *buf, size_t size)
52 if (size > (s->buffer_capacity - s->buffer_size)) {
55 DPRINTF("increasing buffer capacity from %zu by %zu\n",
56 s->buffer_capacity, size + 1024);
58 s->buffer_capacity += size + 1024;
60 tmp = qemu_realloc(s->buffer, s->buffer_capacity);
62 fprintf(stderr, "qemu file buffer expansion failed\n");
69 memcpy(s->buffer + s->buffer_size, buf, size);
70 s->buffer_size += size;
73 static void buffered_flush(QEMUFileBuffered *s)
78 DPRINTF("flush when error, bailing\n");
82 DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size);
84 while (offset < s->buffer_size) {
87 ret = s->put_buffer(s->opaque, s->buffer + offset,
88 s->buffer_size - offset);
90 DPRINTF("backend not ready, freezing\n");
96 DPRINTF("error flushing data, %zd\n", ret);
100 DPRINTF("flushed %zd byte(s)\n", ret);
105 DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size);
106 memmove(s->buffer, s->buffer + offset, s->buffer_size - offset);
107 s->buffer_size -= offset;
110 static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size)
112 QEMUFileBuffered *s = opaque;
116 DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos);
119 DPRINTF("flush when error, bailing\n");
123 DPRINTF("unfreezing output\n");
124 s->freeze_output = 0;
128 while (!s->freeze_output && offset < size) {
129 if (s->bytes_xfer > s->xfer_limit) {
130 DPRINTF("transfer limit exceeded when putting\n");
134 ret = s->put_buffer(s->opaque, buf + offset, size - offset);
135 if (ret == -EAGAIN) {
136 DPRINTF("backend not ready, freezing\n");
137 s->freeze_output = 1;
142 DPRINTF("error putting\n");
148 DPRINTF("put %zd byte(s)\n", ret);
150 s->bytes_xfer += ret;
154 DPRINTF("buffering %d bytes\n", size - offset);
155 buffered_append(s, buf + offset, size - offset);
159 if (pos == 0 && size == 0) {
160 DPRINTF("file is ready\n");
161 if (s->bytes_xfer <= s->xfer_limit) {
162 DPRINTF("notifying client\n");
163 s->put_ready(s->opaque);
170 static int buffered_close(void *opaque)
172 QEMUFileBuffered *s = opaque;
175 DPRINTF("closing\n");
177 while (!s->has_error && s->buffer_size) {
179 if (s->freeze_output)
180 s->wait_for_unfreeze(s);
183 ret = s->close(s->opaque);
185 qemu_del_timer(s->timer);
186 qemu_free_timer(s->timer);
187 qemu_free(s->buffer);
193 static int buffered_rate_limit(void *opaque)
195 QEMUFileBuffered *s = opaque;
200 if (s->freeze_output)
203 if (s->bytes_xfer > s->xfer_limit)
209 static size_t buffered_set_rate_limit(void *opaque, size_t new_rate)
211 QEMUFileBuffered *s = opaque;
216 s->xfer_limit = new_rate / 10;
219 return s->xfer_limit;
222 static size_t buffered_get_rate_limit(void *opaque)
224 QEMUFileBuffered *s = opaque;
226 return s->xfer_limit;
229 static void buffered_rate_tick(void *opaque)
231 QEMUFileBuffered *s = opaque;
238 qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
240 if (s->freeze_output)
247 /* Add some checks around this */
248 s->put_ready(s->opaque);
251 QEMUFile *qemu_fopen_ops_buffered(void *opaque,
252 size_t bytes_per_sec,
253 BufferedPutFunc *put_buffer,
254 BufferedPutReadyFunc *put_ready,
255 BufferedWaitForUnfreezeFunc *wait_for_unfreeze,
256 BufferedCloseFunc *close)
260 s = qemu_mallocz(sizeof(*s));
263 s->xfer_limit = bytes_per_sec / 10;
264 s->put_buffer = put_buffer;
265 s->put_ready = put_ready;
266 s->wait_for_unfreeze = wait_for_unfreeze;
269 s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
270 buffered_close, buffered_rate_limit,
271 buffered_set_rate_limit,
272 buffered_get_rate_limit);
274 s->timer = qemu_new_timer(rt_clock, buffered_rate_tick, s);
276 qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);