--- /dev/null
+/*
+ * 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 "block/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 int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int 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 int buf_put_buffer(void *opaque, const uint8_t *buf,
+ int64_t pos, int 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_malloc0(sizeof(QEMUBuffer));
+ 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;
+}
Code Review / kvmfornfv.git / blobdiff