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/*
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* QEMU buffered QEMUFile
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*
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* Copyright IBM, Corp. 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#include "qemu-common.h" |
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#include "hw/hw.h" |
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#include "qemu/timer.h" |
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#include "buffered_file.h" |
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//#define DEBUG_BUFFERED_FILE
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typedef struct QEMUFileBuffered |
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{ |
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MigrationState *migration_state; |
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QEMUFile *file; |
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int freeze_output;
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size_t bytes_xfer; |
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size_t xfer_limit; |
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uint8_t *buffer; |
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size_t buffer_size; |
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size_t buffer_capacity; |
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QEMUTimer *timer; |
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} QEMUFileBuffered; |
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#ifdef DEBUG_BUFFERED_FILE
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#define DPRINTF(fmt, ...) \
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do { printf("buffered-file: " fmt, ## __VA_ARGS__); } while (0) |
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#else
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#define DPRINTF(fmt, ...) \
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do { } while (0) |
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#endif
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static void buffered_append(QEMUFileBuffered *s, |
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const uint8_t *buf, size_t size)
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{ |
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if (size > (s->buffer_capacity - s->buffer_size)) {
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DPRINTF("increasing buffer capacity from %zu by %zu\n",
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s->buffer_capacity, size + 1024);
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s->buffer_capacity += size + 1024;
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s->buffer = g_realloc(s->buffer, s->buffer_capacity); |
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} |
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memcpy(s->buffer + s->buffer_size, buf, size); |
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s->buffer_size += size; |
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} |
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static ssize_t buffered_flush(QEMUFileBuffered *s)
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{ |
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size_t offset = 0;
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ssize_t ret = 0;
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DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size);
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while (s->bytes_xfer < s->xfer_limit && offset < s->buffer_size) {
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ret = migrate_fd_put_buffer(s->migration_state, s->buffer + offset, |
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s->buffer_size - offset); |
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if (ret == -EAGAIN) {
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DPRINTF("backend not ready, freezing\n");
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ret = 0;
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s->freeze_output = 1;
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break;
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} |
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if (ret <= 0) { |
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DPRINTF("error flushing data, %zd\n", ret);
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break;
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} else {
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DPRINTF("flushed %zd byte(s)\n", ret);
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offset += ret; |
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s->bytes_xfer += ret; |
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} |
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} |
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DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size);
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memmove(s->buffer, s->buffer + offset, s->buffer_size - offset); |
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s->buffer_size -= offset; |
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if (ret < 0) { |
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return ret;
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} |
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return offset;
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} |
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static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, int size) |
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{ |
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QEMUFileBuffered *s = opaque; |
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ssize_t error; |
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DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos); |
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error = qemu_file_get_error(s->file); |
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if (error) {
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DPRINTF("flush when error, bailing: %s\n", strerror(-error));
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return error;
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} |
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DPRINTF("unfreezing output\n");
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s->freeze_output = 0;
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if (size > 0) { |
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DPRINTF("buffering %d bytes\n", size - offset);
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buffered_append(s, buf, size); |
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} |
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error = buffered_flush(s); |
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if (error < 0) { |
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DPRINTF("buffered flush error. bailing: %s\n", strerror(-error));
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return error;
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} |
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if (pos == 0 && size == 0) { |
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DPRINTF("file is ready\n");
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if (!s->freeze_output && s->bytes_xfer < s->xfer_limit) {
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DPRINTF("notifying client\n");
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migrate_fd_put_ready(s->migration_state); |
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} |
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} |
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return size;
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} |
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static int buffered_close(void *opaque) |
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{ |
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QEMUFileBuffered *s = opaque; |
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ssize_t ret = 0;
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int ret2;
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DPRINTF("closing\n");
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s->xfer_limit = INT_MAX; |
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while (!qemu_file_get_error(s->file) && s->buffer_size) {
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ret = buffered_flush(s); |
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if (ret < 0) { |
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break;
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} |
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if (s->freeze_output) {
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ret = migrate_fd_wait_for_unfreeze(s->migration_state); |
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if (ret < 0) { |
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break;
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} |
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} |
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} |
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ret2 = migrate_fd_close(s->migration_state); |
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if (ret >= 0) { |
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ret = ret2; |
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} |
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qemu_del_timer(s->timer); |
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qemu_free_timer(s->timer); |
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g_free(s->buffer); |
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g_free(s); |
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return ret;
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} |
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/*
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* The meaning of the return values is:
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* 0: We can continue sending
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* 1: Time to stop
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* negative: There has been an error
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*/
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static int buffered_get_fd(void *opaque) |
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{ |
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QEMUFileBuffered *s = opaque; |
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return qemu_get_fd(s->file);
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} |
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static int buffered_rate_limit(void *opaque) |
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{ |
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QEMUFileBuffered *s = opaque; |
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int ret;
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ret = qemu_file_get_error(s->file); |
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if (ret) {
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return ret;
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} |
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if (s->freeze_output)
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return 1; |
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if (s->bytes_xfer > s->xfer_limit)
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return 1; |
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return 0; |
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} |
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static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate) |
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{ |
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QEMUFileBuffered *s = opaque; |
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if (qemu_file_get_error(s->file)) {
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goto out;
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} |
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if (new_rate > SIZE_MAX) {
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new_rate = SIZE_MAX; |
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} |
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s->xfer_limit = new_rate / 10;
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out:
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return s->xfer_limit;
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} |
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static int64_t buffered_get_rate_limit(void *opaque) |
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{ |
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QEMUFileBuffered *s = opaque; |
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return s->xfer_limit;
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} |
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static void buffered_rate_tick(void *opaque) |
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{ |
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QEMUFileBuffered *s = opaque; |
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if (qemu_file_get_error(s->file)) {
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buffered_close(s); |
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return;
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} |
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qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100);
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if (s->freeze_output)
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return;
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s->bytes_xfer = 0;
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buffered_put_buffer(s, NULL, 0, 0); |
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} |
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static const QEMUFileOps buffered_file_ops = { |
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.get_fd = buffered_get_fd, |
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.put_buffer = buffered_put_buffer, |
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.close = buffered_close, |
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.rate_limit = buffered_rate_limit, |
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.get_rate_limit = buffered_get_rate_limit, |
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.set_rate_limit = buffered_set_rate_limit, |
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}; |
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QEMUFile *qemu_fopen_ops_buffered(MigrationState *migration_state) |
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{ |
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QEMUFileBuffered *s; |
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s = g_malloc0(sizeof(*s));
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s->migration_state = migration_state; |
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s->xfer_limit = migration_state->bandwidth_limit / 10;
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s->file = qemu_fopen_ops(s, &buffered_file_ops); |
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s->timer = qemu_new_timer_ms(rt_clock, buffered_rate_tick, s); |
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qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100);
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return s->file;
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} |