[Qemu-devel] Re: [PATCH 02/17] vrtio-9p: Implement P9_TVERSION for 9P

[Michael S. Tsirkin]

On Wed, Mar 03, 2010 at 01:00:59PM -0600, Anthony Liguori wrote:
> address@hidden: malloc to qemu_malloc coversion]
> 
> Signed-off-by: Anthony Liguori <address@hidden>
> Signed-off-by: Aneesh Kumar K.V <address@hidden>
> ---
>  hw/virtio-9p.c |  263 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 262 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
> index 93402c5..a057fbb 100644
> --- a/hw/virtio-9p.c
> +++ b/hw/virtio-9p.c
> @@ -111,10 +111,271 @@ static void free_pdu(V9fsState *s, V9fsPDU *pdu)
>      }
>  }
>  
> -static void v9fs_version(V9fsState *s, V9fsPDU *pdu)
> +static void v9fs_string_free(V9fsString *str)
> +{
> +    free(str->data);
> +    str->data = NULL;
> +    str->size = 0;
> +}
> +
> +static size_t pdu_unpack(void *dst, V9fsPDU *pdu, size_t offset, size_t size)
> +{
> +    struct iovec *sg = pdu->elem.out_sg;
> +    BUG_ON((offset + size) > sg[0].iov_len);
> +    memcpy(dst, sg[0].iov_base + offset, size);
> +    return size;
> +}
> +
> +/* FIXME i can do this with less variables */
> +static size_t pdu_pack(V9fsPDU *pdu, size_t offset, const void *src, size_t 
> size)

Is the point of this functuion to copy size bytes starting
at offset? Maybe generalize this to work on any iovec?

> +{
> +    struct iovec *sg = pdu->elem.in_sg;
> +    size_t off = 0;
> +    size_t copied = 0;
> +    int i = 0;
> +
> +    for (i = 0; size && i < pdu->elem.in_num; i++) {
> +     size_t len;

indentation by tabs.

> +
> +     if (offset >= off && offset < (off + sg[i].iov_len)) {

The above math might overflow. Not sure what the result will be.

> +         len = MIN(sg[i].iov_len - (offset - off), size);
> +         memcpy(sg[i].iov_base + (offset - off), src, len);
> +         size -= len;
> +         offset += len;
> +         off = offset;
> +         copied += len;
> +         src += len;
> +     } else
> +         off += sg[i].iov_len;

{}

> +    }
> +
> +    return copied;
> +}
> +
> +static int pdu_copy_sg(V9fsPDU *pdu, size_t offset, int rx, struct iovec *sg)
> +{

Maybe generalize this to work on any iovec?

> +    size_t pos = 0;
> +    int i, j;
> +    struct iovec *src_sg;
> +    unsigned int num;
> +
> +    if (rx) {
> +         src_sg = pdu->elem.in_sg;
> +         num = pdu->elem.in_num;
> +    } else {
> +         src_sg = pdu->elem.out_sg;
> +         num = pdu->elem.out_num;
> +    }
> +
> +    j = 0;
> +    for (i = 0; i < num; i++) {
> +     if (offset <= pos) {
> +         sg[j].iov_base = src_sg[i].iov_base;
> +         sg[j].iov_len = src_sg[i].iov_len;
> +         j++;
> +     } else if (offset < (src_sg[i].iov_len + pos)) {
> +         sg[j].iov_base = src_sg[i].iov_base;
> +         sg[j].iov_len = src_sg[i].iov_len;
> +         sg[j].iov_base += (offset - pos);
> +         sg[j].iov_len -= (offset - pos);
> +         j++;
> +     }
> +     pos += src_sg[i].iov_len;
> +    }
> +
> +    return j;
> +}
> +
> +static size_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, 
> ...)
> +{
> +    size_t old_offset = offset;
> +    va_list ap;
> +    int i;
> +
> +    va_start(ap, fmt);
> +    for (i = 0; fmt[i]; i++) {
> +     switch (fmt[i]) {
> +     case 'b': {
> +         int8_t *valp = va_arg(ap, int8_t *);
> +         offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
> +         break;
> +     }
> +     case 'w': {
> +         int16_t *valp = va_arg(ap, int16_t *);
> +         offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
> +         break;
> +     }
> +     case 'd': {
> +         int32_t *valp = va_arg(ap, int32_t *);
> +         offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
> +         break;
> +     }
> +     case 'q': {
> +         int64_t *valp = va_arg(ap, int64_t *);
> +         offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
> +         break;
> +     }
> +     case 'v': {
> +         struct iovec *iov = va_arg(ap, struct iovec *);
> +         int *iovcnt = va_arg(ap, int *);
> +         *iovcnt = pdu_copy_sg(pdu, offset, 0, iov);
> +         break;
> +     }
> +     case 's': {
> +         V9fsString *str = va_arg(ap, V9fsString *);
> +         offset += pdu_unmarshal(pdu, offset, "w", &str->size);
> +         /* FIXME: sanity check str->size */
> +         str->data = qemu_malloc(str->size + 1);
> +         offset += pdu_unpack(str->data, pdu, offset, str->size);
> +         str->data[str->size] = 0;
> +         break;
> +     }
> +     case 'Q': {
> +         V9fsQID *qidp = va_arg(ap, V9fsQID *);
> +         offset += pdu_unmarshal(pdu, offset, "bdq",
> +                                 &qidp->type, &qidp->version, &qidp->path);
> +         break;
> +     }
> +     case 'S': {
> +         V9fsStat *statp = va_arg(ap, V9fsStat *);
> +         offset += pdu_unmarshal(pdu, offset, "wwdQdddqsssssddd",
> +                                 &statp->size, &statp->type, &statp->dev,
> +                                 &statp->qid, &statp->mode, &statp->atime,
> +                                 &statp->mtime, &statp->length,
> +                                 &statp->name, &statp->uid, &statp->gid,
> +                                 &statp->muid, &statp->extension,
> +                                 &statp->n_uid, &statp->n_gid,
> +                                 &statp->n_muid);
> +         break;
> +     }
> +     default:
> +         break;
> +     }
> +    }
> +
> +    va_end(ap);
> +
> +    return offset - old_offset;
> +}
> +
> +static size_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>  {
> +    size_t old_offset = offset;
> +    va_list ap;
> +    int i;
> +
> +    va_start(ap, fmt);
> +    for (i = 0; fmt[i]; i++) {
> +     switch (fmt[i]) {
> +     case 'b': {
> +         int8_t val = va_arg(ap, int);
> +         offset += pdu_pack(pdu, offset, &val, sizeof(val));
> +         break;
> +     }
> +     case 'w': {
> +         int16_t val = va_arg(ap, int);
> +         offset += pdu_pack(pdu, offset, &val, sizeof(val));
> +         break;
> +     }
> +     case 'd': {
> +         int32_t val = va_arg(ap, int);
> +         offset += pdu_pack(pdu, offset, &val, sizeof(val));
> +         break;
> +     }
> +     case 'q': {
> +         int64_t val = va_arg(ap, int64_t);
> +         offset += pdu_pack(pdu, offset, &val, sizeof(val));
> +         break;
> +     }
> +     case 'v': {
> +         struct iovec *iov = va_arg(ap, struct iovec *);
> +         int *iovcnt = va_arg(ap, int *);
> +         *iovcnt = pdu_copy_sg(pdu, offset, 1, iov);
> +         break;
> +     }
> +     case 's': {
> +         V9fsString *str = va_arg(ap, V9fsString *);
> +         offset += pdu_marshal(pdu, offset, "w", str->size);
> +         offset += pdu_pack(pdu, offset, str->data, str->size);
> +         break;
> +     }
> +     case 'Q': {
> +         V9fsQID *qidp = va_arg(ap, V9fsQID *);
> +         offset += pdu_marshal(pdu, offset, "bdq",
> +                               qidp->type, qidp->version, qidp->path);
> +         break;
> +     }
> +     case 'S': {
> +         V9fsStat *statp = va_arg(ap, V9fsStat *);
> +         offset += pdu_marshal(pdu, offset, "wwdQdddqsssssddd",
> +                               statp->size, statp->type, statp->dev,
> +                               &statp->qid, statp->mode, statp->atime,
> +                               statp->mtime, statp->length, &statp->name,
> +                               &statp->uid, &statp->gid, &statp->muid,
> +                               &statp->extension, statp->n_uid,
> +                               statp->n_gid, statp->n_muid);
> +         break;
> +     }
> +     default:
> +         break;
> +     }
> +    }
> +    va_end(ap);
> +
> +    return offset - old_offset;
> +}
> +
> +static void complete_pdu(V9fsState *s, V9fsPDU *pdu, ssize_t len)
> +{
> +    int8_t id = pdu->id + 1; /* Response */
> +
> +    if (len < 0) {
> +     V9fsString str;
> +     int err = -len;
> +
> +     str.data = strerror(err);
> +     str.size = strlen(str.data);
> +
> +     len = 7;
> +     len += pdu_marshal(pdu, len, "s", &str);
> +     if (dotu)
> +         len += pdu_marshal(pdu, len, "d", err);
> +
> +     id = P9_RERROR;
> +    }
> +
> +    /* fill out the header */
> +    pdu_marshal(pdu, 0, "dbw", (int32_t)len, id, pdu->tag);
> +
> +    /* keep these in sync */
> +    pdu->size = len;
> +    pdu->id = id;
> +
>      if (debug_9p_pdu)
>       pprint_pdu(pdu);
> +
> +    /* push onto queue and notify */
> +    virtqueue_push(s->vq, &pdu->elem, len);
> +
> +    /* FIXME: we should batch these completions */
> +    virtio_notify(&s->vdev, s->vq);
> +
> +    free_pdu(s, pdu);
> +}
> +
> +static void v9fs_version(V9fsState *s, V9fsPDU *pdu)
> +{
> +    int32_t msize;
> +    V9fsString version;
> +    size_t offset = 7;
> +
> +    pdu_unmarshal(pdu, offset, "ds", &msize, &version);
> +    BUG_ON(strcmp(version.data, "9P2000.u") != 0);
> +
> +    offset += pdu_marshal(pdu, offset, "ds", msize, &version);
> +    complete_pdu(s, pdu, offset);
> +
> +    v9fs_string_free(&version);
>  }
>  
>  static void v9fs_attach(V9fsState *s, V9fsPDU *pdu)
> -- 
> 1.6.5.2
> 
>