From 977184db39678624c1fc11d0d834a33127745904 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Fri, 12 Dec 2014 11:13:41 +0000 Subject: Split the QEMU buffered file code out The splitting of qemu-file and addition of the buffered file landed at the same time; so now split the buffered file code out. Signed-off-by: Dr. David Alan Gilbert Signed-off-by: Amit Shah --- migration/qemu-file.c | 455 -------------------------------------------------- 1 file changed, 455 deletions(-) (limited to 'migration/qemu-file.c') diff --git a/migration/qemu-file.c b/migration/qemu-file.c index 671fba988a..d2d40073f0 100644 --- a/migration/qemu-file.c +++ b/migration/qemu-file.c @@ -517,458 +517,3 @@ uint64_t qemu_get_be64(QEMUFile *f) v |= qemu_get_be32(f); return v; } - -#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; -} - -/** - * Create a deep copy of the given QEMUSizedBuffer. - * - * @qsb: A QEMUSizedBuffer - * - * Returns a clone of @qsb or NULL on allocation failure - */ -QEMUSizedBuffer *qsb_clone(const QEMUSizedBuffer *qsb) -{ - QEMUSizedBuffer *out = qsb_create(NULL, qsb_get_length(qsb)); - size_t i; - ssize_t res; - off_t pos = 0; - - if (!out) { - return NULL; - } - - for (i = 0; i < qsb->n_iov; i++) { - res = qsb_write_at(out, qsb->iov[i].iov_base, - pos, qsb->iov[i].iov_len); - if (res < 0) { - qsb_free(out); - return NULL; - } - pos += res; - } - - return out; -} - -typedef struct QEMUBuffer { - QEMUSizedBuffer *qsb; - QEMUFile *file; -} 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; - - 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)); - if (mode[0] == 'r') { - s->qsb = input; - } - - if (s->qsb == NULL) { - s->qsb = qsb_create(NULL, 0); - } - 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; -} -- cgit v1.2.1