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/*
* QEMU buffered QEMUFile
*
* Copyright IBM, Corp. 2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu-common.h"
#include "hw/hw.h"
#include "qemu-timer.h"
#include "sysemu.h"
#include "qemu-char.h"
#include "buffered_file.h"
//#define DEBUG_BUFFERED_FILE
typedef struct QEMUFileBuffered
{
BufferedPutFunc *put_buffer;
BufferedPutReadyFunc *put_ready;
BufferedWaitForUnfreezeFunc *wait_for_unfreeze;
BufferedCloseFunc *close;
void *opaque;
QEMUFile *file;
int has_error;
int freeze_output;
size_t bytes_xfer;
size_t xfer_limit;
uint8_t *buffer;
size_t buffer_size;
size_t buffer_capacity;
QEMUTimer *timer;
} QEMUFileBuffered;
#ifdef DEBUG_BUFFERED_FILE
#define DPRINTF(fmt, ...) \
do { printf("buffered-file: " fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
do { } while (0)
#endif
static void buffered_append(QEMUFileBuffered *s,
const uint8_t *buf, size_t size)
{
if (size > (s->buffer_capacity - s->buffer_size)) {
void *tmp;
DPRINTF("increasing buffer capacity from %zu by %zu\n",
s->buffer_capacity, size + 1024);
s->buffer_capacity += size + 1024;
tmp = qemu_realloc(s->buffer, s->buffer_capacity);
if (tmp == NULL) {
fprintf(stderr, "qemu file buffer expansion failed\n");
exit(1);
}
s->buffer = tmp;
}
memcpy(s->buffer + s->buffer_size, buf, size);
s->buffer_size += size;
}
static void buffered_flush(QEMUFileBuffered *s)
{
size_t offset = 0;
if (s->has_error) {
DPRINTF("flush when error, bailing\n");
return;
}
DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size);
while (offset < s->buffer_size) {
ssize_t ret;
ret = s->put_buffer(s->opaque, s->buffer + offset,
s->buffer_size - offset);
if (ret == -EAGAIN) {
DPRINTF("backend not ready, freezing\n");
s->freeze_output = 1;
break;
}
if (ret <= 0) {
DPRINTF("error flushing data, %zd\n", ret);
s->has_error = 1;
break;
} else {
DPRINTF("flushed %zd byte(s)\n", ret);
offset += ret;
}
}
DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size);
memmove(s->buffer, s->buffer + offset, s->buffer_size - offset);
s->buffer_size -= offset;
}
static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size)
{
QEMUFileBuffered *s = opaque;
int offset = 0;
ssize_t ret;
DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos);
if (s->has_error) {
DPRINTF("flush when error, bailing\n");
return -EINVAL;
}
DPRINTF("unfreezing output\n");
s->freeze_output = 0;
buffered_flush(s);
while (!s->freeze_output && offset < size) {
if (s->bytes_xfer > s->xfer_limit) {
DPRINTF("transfer limit exceeded when putting\n");
break;
}
ret = s->put_buffer(s->opaque, buf + offset, size - offset);
if (ret == -EAGAIN) {
DPRINTF("backend not ready, freezing\n");
s->freeze_output = 1;
break;
}
if (ret <= 0) {
DPRINTF("error putting\n");
s->has_error = 1;
offset = -EINVAL;
break;
}
DPRINTF("put %zd byte(s)\n", ret);
offset += ret;
s->bytes_xfer += ret;
}
if (offset >= 0) {
DPRINTF("buffering %d bytes\n", size - offset);
buffered_append(s, buf + offset, size - offset);
offset = size;
}
if (pos == 0 && size == 0) {
DPRINTF("file is ready\n");
if (s->bytes_xfer <= s->xfer_limit) {
DPRINTF("notifying client\n");
s->put_ready(s->opaque);
}
}
return offset;
}
static int buffered_close(void *opaque)
{
QEMUFileBuffered *s = opaque;
int ret;
DPRINTF("closing\n");
while (!s->has_error && s->buffer_size) {
buffered_flush(s);
if (s->freeze_output)
s->wait_for_unfreeze(s);
}
ret = s->close(s->opaque);
qemu_del_timer(s->timer);
qemu_free_timer(s->timer);
qemu_free(s->buffer);
qemu_free(s);
return ret;
}
static int buffered_rate_limit(void *opaque)
{
QEMUFileBuffered *s = opaque;
if (s->has_error)
return 0;
if (s->freeze_output)
return 1;
if (s->bytes_xfer > s->xfer_limit)
return 1;
return 0;
}
static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate)
{
QEMUFileBuffered *s = opaque;
if (s->has_error)
goto out;
if (new_rate > SIZE_MAX) {
new_rate = SIZE_MAX;
}
s->xfer_limit = new_rate / 10;
out:
return s->xfer_limit;
}
static int64_t buffered_get_rate_limit(void *opaque)
{
QEMUFileBuffered *s = opaque;
return s->xfer_limit;
}
static void buffered_rate_tick(void *opaque)
{
QEMUFileBuffered *s = opaque;
if (s->has_error) {
buffered_close(s);
return;
}
qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
if (s->freeze_output)
return;
s->bytes_xfer = 0;
buffered_flush(s);
/* Add some checks around this */
s->put_ready(s->opaque);
}
QEMUFile *qemu_fopen_ops_buffered(void *opaque,
size_t bytes_per_sec,
BufferedPutFunc *put_buffer,
BufferedPutReadyFunc *put_ready,
BufferedWaitForUnfreezeFunc *wait_for_unfreeze,
BufferedCloseFunc *close)
{
QEMUFileBuffered *s;
s = qemu_mallocz(sizeof(*s));
s->opaque = opaque;
s->xfer_limit = bytes_per_sec / 10;
s->put_buffer = put_buffer;
s->put_ready = put_ready;
s->wait_for_unfreeze = wait_for_unfreeze;
s->close = close;
s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
buffered_close, buffered_rate_limit,
buffered_set_rate_limit,
buffered_get_rate_limit);
s->timer = qemu_new_timer(rt_clock, buffered_rate_tick, s);
qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 100);
return s->file;
}
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