Re: [Qemu-devel] [PATCH -v2 02/22] vrtio-9p: Implement P9_TVERSION for 9P

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 03/16/2010 04:15 AM, Aneesh Kumar K.V wrote:
> From: Anthony Liguori<aliguori@us.ibm.com>
>
> [kiran@linux.vnet.ibm.com: malloc to qemu_malloc coversion]
>
> Signed-off-by: Anthony Liguori<aliguori@us.ibm.com>
> Signed-off-by: Aneesh Kumar K.V<aneesh.kumar@linux.vnet.ibm.com>
> ---
>   hw/virtio-9p.c |  263 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>   1 files changed, 261 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
> index 115c93b..53b3d78 100644
> --- a/hw/virtio-9p.c
> +++ b/hw/virtio-9p.c
> @@ -111,10 +111,269 @@ static void free_pdu(V9fsState *s, V9fsPDU *pdu)
>       }
>   }
>
> +static void v9fs_string_free(V9fsString *str)
> +{
> +    free(str->data);
>    

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

Adding the marshalling in  patch to implement P9_TVERSION is probably 
not ideal.

Regards,

Anthony Liguori

> +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;
> +
> +    /* 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)
>   {
> -    if (debug_9p_pdu)
> -        pprint_pdu(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)
>