* Dr. David Alan Gilbert (git) (dgilb...@redhat.com) wrote: > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > This is based on Stefan and Joel's patch that creates a QEMUFile that goes > to a memory buffer; from:
Actually, just spotted a bug in this; v4 coming shortly. Dave > > http://lists.gnu.org/archive/html/qemu-devel/2013-03/msg05036.html > > Using the QEMUFile interface, this patch adds support functions for > operating on in-memory sized buffers that can be written to or read from. > > Signed-off-by: Stefan Berger <stef...@linux.vnet.ibm.com> > Signed-off-by: Joel Schopp <jsch...@linux.vnet.ibm.com> > > For fixes/tweeks I've done: > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > --- > include/migration/qemu-file.h | 28 +++ > include/qemu/typedefs.h | 1 + > qemu-file.c | 457 > ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 486 insertions(+) > > diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h > index c90f529..6ef8ebc 100644 > --- a/include/migration/qemu-file.h > +++ b/include/migration/qemu-file.h > @@ -25,6 +25,8 @@ > #define QEMU_FILE_H 1 > #include "exec/cpu-common.h" > > +#include <stdint.h> > + > /* This function writes a chunk of data to a file at the given position. > * The pos argument can be ignored if the file is only being used for > * streaming. The handler should try to write all of the data it can. > @@ -94,11 +96,21 @@ typedef struct QEMUFileOps { > QEMURamSaveFunc *save_page; > } QEMUFileOps; > > +struct QEMUSizedBuffer { > + struct iovec *iov; > + size_t n_iov; > + size_t size; /* total allocated size in all iov's */ > + size_t used; /* number of used bytes */ > +}; > + > +typedef struct QEMUSizedBuffer QEMUSizedBuffer; > + > QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops); > QEMUFile *qemu_fopen(const char *filename, const char *mode); > QEMUFile *qemu_fdopen(int fd, const char *mode); > QEMUFile *qemu_fopen_socket(int fd, const char *mode); > QEMUFile *qemu_popen_cmd(const char *command, const char *mode); > +QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input); > int qemu_get_fd(QEMUFile *f); > int qemu_fclose(QEMUFile *f); > int64_t qemu_ftell(QEMUFile *f); > @@ -111,6 +123,22 @@ void qemu_put_byte(QEMUFile *f, int v); > void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size); > bool qemu_file_mode_is_not_valid(const char *mode); > > +QEMUSizedBuffer *qsb_create(const uint8_t *buffer, size_t len); > +QEMUSizedBuffer *qsb_clone(const QEMUSizedBuffer *); > +void qsb_free(QEMUSizedBuffer *); > +size_t qsb_set_length(QEMUSizedBuffer *qsb, size_t length); > +size_t qsb_get_length(const QEMUSizedBuffer *qsb); > +ssize_t qsb_get_buffer(const QEMUSizedBuffer *, off_t start, size_t count, > + uint8_t *buf); > +ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *buf, > + off_t pos, size_t count); > + > + > +/* > + * For use on files opened with qemu_bufopen > + */ > +const QEMUSizedBuffer *qemu_buf_get(QEMUFile *f); > + > static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v) > { > qemu_put_byte(f, (int)v); > diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h > index 5f20b0e..db1153a 100644 > --- a/include/qemu/typedefs.h > +++ b/include/qemu/typedefs.h > @@ -60,6 +60,7 @@ typedef struct PCIEAERLog PCIEAERLog; > typedef struct PCIEAERErr PCIEAERErr; > typedef struct PCIEPort PCIEPort; > typedef struct PCIESlot PCIESlot; > +typedef struct QEMUSizedBuffer QEMUSizedBuffer; > typedef struct MSIMessage MSIMessage; > typedef struct SerialState SerialState; > typedef struct PCMCIACardState PCMCIACardState; > diff --git a/qemu-file.c b/qemu-file.c > index a8e3912..9b83991 100644 > --- a/qemu-file.c > +++ b/qemu-file.c > @@ -878,3 +878,460 @@ 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) { > + size_t j; > + > + for (j = 0; j < i; j++) { > + g_free(qsb->iov[j].iov_base); > + } > + g_free(qsb->iov); > + g_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 allocated > + * memory for it. > + * > + * @qsb: A QEMUSizedBuffer > + * @new_size: The new size of the buffer > + * > + * Returns an error code in case of memory allocation failure > + * or the new size of the buffer otherwise. 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_malloc_n(qsb->n_iov + needed_chunks, > + sizeof(struct iovec)); > + 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 (!qsb->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 = (QEMUBuffer *)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) { > + 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; > +} > -- > 1.9.3 > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
