/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2014 IBM Corp.
*
* Authors:
* Stefan Berger <stefanb@linux.vnet.ibm.com>
*
* 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-common.h"
#include "qemu/error-report.h"
#include "qemu/iov.h"
#include "qemu/sockets.h"
#include "qemu/coroutine.h"
#include "migration/migration.h"
#include "migration/qemu-file.h"
#include "migration/qemu-file-internal.h"
#include "trace.h"
#define QSB_CHUNK_SIZE (1 << 10)
#define QSB_MAX_CHUNK_SIZE (16 * QSB_CHUNK_SIZE)
/**
* Create a QEMUSizedBuffer
* This type of buffer uses scatter-gather lists internally and
* can grow to any size. Any data array in the scatter-gather list
* can hold different amount of bytes.
*
* @buffer: Optional buffer to copy into the QSB
* @len: size of initial buffer; if @buffer is given, buffer must
* hold at least len bytes
*
* Returns a pointer to a QEMUSizedBuffer or NULL on allocation failure
*/
QEMUSizedBuffer *qsb_create(const uint8_t *buffer, size_t len)
{
QEMUSizedBuffer *qsb;
size_t alloc_len, num_chunks, i, to_copy;
size_t chunk_size = (len > QSB_MAX_CHUNK_SIZE)
? QSB_MAX_CHUNK_SIZE
: QSB_CHUNK_SIZE;
num_chunks = DIV_ROUND_UP(len ? len : QSB_CHUNK_SIZE, chunk_size);
alloc_len = num_chunks * chunk_size;
qsb = g_try_new0(QEMUSizedBuffer, 1);
if (!qsb) {
return NULL;
}
qsb->iov = g_try_new0(struct iovec, num_chunks);
if (!qsb->iov) {
g_free(qsb);
return NULL;
}
qsb->n_iov = num_chunks;
for (i = 0; i < num_chunks; i++) {
qsb->iov[i].iov_base = g_try_malloc0(chunk_size);
if (!qsb->iov[i].iov_base) {
/* qsb_free is safe since g_free can cope with NULL */
qsb_free(qsb);
return NULL;
}
qsb->iov[i].iov_len = chunk_size;
if (buffer) {
to_copy = (len - qsb->used) > chunk_size
? chunk_size : (len - qsb->used);
memcpy(qsb->iov[i].iov_base, &buffer[qsb->used], to_copy);
qsb->used += to_copy;
}
}
qsb->size = alloc_len;
return qsb;
}
/**
* Free the QEMUSizedBuffer
*
* @qsb: The QEMUSizedBuffer to free
*/
void qsb_free(QEMUSizedBuffer *qsb)
{
size_t i;
if (!qsb) {
return;
}
for (i = 0; i < qsb->n_iov; i++) {
g_free(qsb->iov[i].iov_base);
}
g_free(qsb->iov);
g_free(qsb);
}
/**
* Get the number of used bytes in the QEMUSizedBuffer
*
* @qsb: A QEMUSizedBuffer
*
* Returns the number of bytes currently used in this buffer
*/
size_t qsb_get_length(const QEMUSizedBuffer *qsb)
{
return qsb->used;
}
/**
* Set the length of the buffer; the primary usage of this
* function is to truncate the number of used bytes in the buffer.
* The size will not be extended beyond the current number of
* allocated bytes in the QEMUSizedBuffer.
*
* @qsb: A QEMUSizedBuffer
* @new_len: The new length of bytes in the buffer
*
* Returns the number of bytes the buffer was truncated or extended
* to.
*/
size_t qsb_set_length(QEMUSizedBuffer *qsb, size_t new_len)
{
if (new_len <= qsb->size) {
qsb->used = new_len;
} else {
qsb->used = qsb->size;
}
return qsb->used;
}
/**
* Get the iovec that holds the data for a given position @pos.
*
* @qsb: A QEMUSizedBuffer
* @pos: The index of a byte in the buffer
* @d_off: Pointer to an offset that this function will indicate
* at what position within the returned iovec the byte
* is to be found
*
* Returns the index of the iovec that holds the byte at the given
* index @pos in the byte stream; a negative number if the iovec
* for the given position @pos does not exist.
*/
static ssize_t qsb_get_iovec(const QEMUSizedBuffer *qsb,
off_t pos, off_t *d_off)
{
ssize_t i;
off_t curr = 0;
if (pos > qsb->used) {
return -1;
}
for (i = 0; i < qsb->n_iov; i++) {
if (curr + qsb->iov[i].iov_len > pos) {
*d_off = pos - curr;
return i;
}
curr += qsb->iov[i].iov_len;
}
return -1;
}
/*
* Convert the QEMUSizedBuffer into a flat buffer.
*
* Note: If at all possible, try to avoid this function since it
* may unnecessarily copy memory around.
*
* @qsb: pointer to QEMUSizedBuffer
* @start: offset to start at
* @count: number of bytes to copy
* @buf: a pointer to a buffer to write into (at least @count bytes)
*
* Returns the number of bytes copied into the output buffer
*/
ssize_t qsb_get_buffer(const QEMUSizedBuffer *qsb, off_t start,
size_t count, uint8_t *buffer)
{
const struct iovec *iov;
size_t to_copy, all_copy;
ssize_t index;
off_t s_off;
off_t d_off = 0;
char *s;
if (start > qsb->used) {
return 0;
}
all_copy = qsb->used - start;
if (all_copy > count) {
all_copy = count;
} else {
count = all_copy;
}
index = qsb_get_iovec(qsb, start, &s_off);
if (index < 0) {
return 0;
}
while (all_copy > 0) {
iov = &qsb->iov[index];
s = iov->iov_base;
to_copy = iov->iov_len - s_off;
if (to_copy > all_copy) {
to_copy = all_copy;
}
memcpy(&buffer[d_off], &s[s_off], to_copy);
d_off += to_copy;
all_copy -= to_copy;
s_off = 0;
index++;
}
return count;
}
/**
* Grow the QEMUSizedBuffer to the given size and allocate
* memory for it.
*
* @qsb: A QEMUSizedBuffer
* @new_size: The new size of the buffer
*
* Return:
* a negative error code in case of memory allocation failure
* or
* the new size of the buffer. The returned size may be greater or equal
* to @new_size.
*/
static ssize_t qsb_grow(QEMUSizedBuffer *qsb, size_t new_size)
{
size_t needed_chunks, i;
if (qsb->size < new_size) {
struct iovec *new_iov;
size_t size_diff = new_size - qsb->size;
size_t chunk_size = (size_diff > QSB_MAX_CHUNK_SIZE)
? QSB_MAX_CHUNK_SIZE : QSB_CHUNK_SIZE;
needed_chunks = DIV_ROUND_UP(size_diff, chunk_size);
new_iov = g_try_new(struct iovec, qsb->n_iov + needed_chunks);
if (new_iov == NULL) {
return -ENOMEM;
}
/* Allocate new chunks as needed into new_iov */
for (i = qsb->n_iov; i < qsb->n_iov + needed_chunks; i++) {
new_iov[i].iov_base = g_try_malloc0(chunk_size);
new_iov[i].iov_len = chunk_size;
if (!new_iov[i].iov_base) {
size_t j;
/* Free previously allocated new chunks */
for (j = qsb->n_iov; j < i; j++) {
g_free(new_iov[j].iov_base);
}
g_free(new_iov);
return -ENOMEM;
}
}
/*
* Now we can't get any allocation errors, copy over to new iov
* and switch.
*/
for (i = 0; i < qsb->n_iov; i++) {
new_iov[i] = qsb->iov[i];
}
qsb->n_iov += needed_chunks;
g_free(qsb->iov);
qsb->iov = new_iov;
qsb->size += (needed_chunks * chunk_size);
}
return qsb->size;
}
/**
* Write into the QEMUSizedBuffer at a given position and a given
* number of bytes. This function will automatically grow the
* QEMUSizedBuffer.
*
* @qsb: A QEMUSizedBuffer
* @source: A byte array to copy data from
* @pos: The position within the @qsb to write data to
* @size: The number of bytes to copy into the @qsb
*
* Returns @size or a negative error code in case of memory allocation failure,
* or with an invalid 'pos'
*/
ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *source,
off_t pos, size_t count)
{
ssize_t rc = qsb_grow(qsb, pos + count);
size_t to_copy;
size_t all_copy = count;
const struct iovec *iov;
ssize_t index;
char *dest;
off_t d_off, s_off = 0;
if (rc < 0) {
return rc;
}
if (pos + count > qsb->used) {
qsb->used = pos + count;
}
index = qsb_get_iovec(qsb, pos, &d_off);
if (index < 0) {
return -EINVAL;
}
while (all_copy > 0) {
iov = &qsb->iov[index];
dest = iov->iov_base;
to_copy = iov->iov_len - d_off;
if (to_copy > all_copy) {
to_copy = all_copy;
}
memcpy(&dest[d_off], &source[s_off], to_copy);
s_off += to_copy;
all_copy -= to_copy;
d_off = 0;
index++;
}
return count;
}
typedef struct QEMUBuffer {
QEMUSizedBuffer *qsb;
QEMUFile *file;
bool qsb_allocated;
} QEMUBuffer;
static ssize_t buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
size_t size)
{
QEMUBuffer *s = opaque;
ssize_t len = qsb_get_length(s->qsb) - pos;
if (len <= 0) {
return 0;
}
if (len > size) {
len = size;
}
return qsb_get_buffer(s->qsb, pos, len, buf);
}
static ssize_t buf_put_buffer(void *opaque, const uint8_t *buf,
int64_t pos, size_t size)
{
QEMUBuffer *s = opaque;
return qsb_write_at(s->qsb, buf, pos, size);
}
static int buf_close(void *opaque)
{
QEMUBuffer *s = opaque;
if (s->qsb_allocated) {
qsb_free(s->qsb);
}
g_free(s);
return 0;
}
const QEMUSizedBuffer *qemu_buf_get(QEMUFile *f)
{
QEMUBuffer *p;
qemu_fflush(f);
p = f->opaque;
return p->qsb;
}
static const QEMUFileOps buf_read_ops = {
.get_buffer = buf_get_buffer,
.close = buf_close,
};
static const QEMUFileOps buf_write_ops = {
.put_buffer = buf_put_buffer,
.close = buf_close,
};
QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input)
{
QEMUBuffer *s;
if (mode == NULL || (mode[0] != 'r' && mode[0] != 'w') ||
mode[1] != '\0') {
error_report("qemu_bufopen: Argument validity check failed");
return NULL;
}
s = g_new0(QEMUBuffer, 1);
s->qsb = input;
if (s->qsb == NULL) {
s->qsb = qsb_create(NULL, 0);
s->qsb_allocated = true;
}
if (!s->qsb) {
g_free(s);
error_report("qemu_bufopen: qsb_create failed");
return NULL;
}
if (mode[0] == 'r') {
s->file = qemu_fopen_ops(s, &buf_read_ops);
} else {
s->file = qemu_fopen_ops(s, &buf_write_ops);
}
return s->file;
}
