Re: [Qemu-devel] [PATCH v4 5/5] usb-mtp: Advertise SendObjectInfo for write support

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Feb 20, 2018 at 05:59:04PM -0500, Bandan Das wrote:
> This patch implements a dummy ObjectInfo structure so that
> it's easy to typecast the incoming data. If the metadata is
> valid, write_pending is set. Also, the incoming filename
> is utf-16, so, instead of depending on external libraries, just
> implement a simple function to get the filename
> 
> Signed-off-by: Bandan Das <bsd@redhat.com>
> ---
>  hw/usb/dev-mtp.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 130 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
> index 9b51708614..086296f415 100644
> --- a/hw/usb/dev-mtp.c
> +++ b/hw/usb/dev-mtp.c
> @@ -47,6 +47,7 @@ enum mtp_code {
>      CMD_GET_OBJECT_INFO            = 0x1008,
>      CMD_GET_OBJECT                 = 0x1009,
>      CMD_DELETE_OBJECT              = 0x100b,
> +    CMD_SEND_OBJECT_INFO           = 0x100c,
>      CMD_SEND_OBJECT                = 0x100d,
>      CMD_GET_PARTIAL_OBJECT         = 0x101b,
>      CMD_GET_OBJECT_PROPS_SUPPORTED = 0x9801,
> @@ -67,8 +68,10 @@ enum mtp_code {
>      RES_STORE_FULL                 = 0x200c,
>      RES_STORE_READ_ONLY            = 0x200e,
>      RES_PARTIAL_DELETE             = 0x2012,
> +    RES_STORE_NOT_AVAILABLE        = 0x2013,
>      RES_SPEC_BY_FORMAT_UNSUPPORTED = 0x2014,
>      RES_INVALID_OBJECTINFO         = 0x2015,
> +    RES_DESTINATION_UNSUPPORTED    = 0x2020,
>      RES_INVALID_PARENT_OBJECT      = 0x201a,
>      RES_INVALID_PARAMETER          = 0x201d,
>      RES_SESSION_ALREADY_OPEN       = 0x201e,
> @@ -196,6 +199,34 @@ struct MTPState {
>      } dataset;
>  };
>  
> +/*
> + * ObjectInfo dataset received from initiator
> + * Fields we don't care about are ignored
> + */
> +typedef struct {
> +    uint32_t storage_id; /*unused*/
> +    uint16_t format;
> +    uint16_t protection_status; /*unused*/
> +    uint32_t size;
> +    uint16_t thumb_format; /*unused*/
> +    uint32_t thumb_comp_sz; /*unused*/
> +    uint32_t thumb_pix_width; /*unused*/
> +    uint32_t thumb_pix_height; /*unused*/
> +    uint32_t image_pix_width; /*unused*/
> +    uint32_t image_pix_height; /*unused*/
> +    uint32_t image_bit_depth; /*unused*/
> +    uint32_t parent; /*unused*/
> +    uint16_t assoc_type;
> +    uint32_t assoc_desc;
> +    uint32_t seq_no; /*unused*/
> +    uint8_t length; /*part of filename field*/
> +    uint16_t filename[0];
> +    char date_created[0]; /*unused*/
> +    char date_modified[0]; /*unused*/
> +    char keywords[0]; /*unused*/
> +    /* string and other data follows */
> +} QEMU_PACKED ObjectInfo;
> +
>  #define TYPE_USB_MTP "usb-mtp"
>  #define USB_MTP(obj) OBJECT_CHECK(MTPState, (obj), TYPE_USB_MTP)
>  
> @@ -437,7 +468,6 @@ static MTPObject *usb_mtp_add_child(MTPState *s, MTPObject *o,
>      return child;
>  }
>  
> -#ifdef CONFIG_INOTIFY1
>  static MTPObject *usb_mtp_object_lookup_name(MTPObject *parent,
>                                               char *name, int len)
>  {
> @@ -452,6 +482,7 @@ static MTPObject *usb_mtp_object_lookup_name(MTPObject *parent,
>      return NULL;
>  }
>  
> +#ifdef CONFIG_INOTIFY1
>  static MTPObject *usb_mtp_object_lookup_wd(MTPState *s, int wd)
>  {
>      MTPObject *iter;
> @@ -815,6 +846,7 @@ static MTPData *usb_mtp_get_device_info(MTPState *s, MTPControl *c)
>          CMD_GET_OBJECT_HANDLES,
>          CMD_GET_OBJECT_INFO,
>          CMD_DELETE_OBJECT,
> +        CMD_SEND_OBJECT_INFO,

Same question about filtering this out for read-only devices,
and somewhere else in this patch validating it too.

>          CMD_SEND_OBJECT,
>          CMD_GET_OBJECT,
>          CMD_GET_PARTIAL_OBJECT,
> @@ -1243,7 +1275,7 @@ static void usb_mtp_object_delete(MTPState *s, uint32_t handle,
>  static void usb_mtp_command(MTPState *s, MTPControl *c)
>  {
>      MTPData *data_in = NULL;
> -    MTPObject *o;
> +    MTPObject *o = NULL;
>      uint32_t nres = 0, res0 = 0;
>  
>      /* sanity checks */
> @@ -1390,6 +1422,37 @@ static void usb_mtp_command(MTPState *s, MTPControl *c)
>          nres = 1;
>          res0 = data_in->length;
>          break;
> +    case CMD_SEND_OBJECT_INFO:
> +        /* First parameter points to storage id or is 0 */
> +        if (c->argv[0] && (c->argv[0] != QEMU_STORAGE_ID)) {
> +            usb_mtp_queue_result(s, RES_STORE_NOT_AVAILABLE, c->trans,
> +                                 0, 0, 0, 0);
> +        } else if (c->argv[1] && !c->argv[0]) {
> +            /* If second parameter is specified, first must also be specified */
> +            usb_mtp_queue_result(s, RES_DESTINATION_UNSUPPORTED, c->trans,
> +                                 0, 0, 0, 0);
> +        } else {
> +            uint32_t handle = c->argv[1];
> +            if (handle == 0xFFFFFFFF || handle == 0) {
> +                /* root object */
> +                o = QTAILQ_FIRST(&s->objects);
> +            } else {
> +                o = usb_mtp_object_lookup(s, handle);
> +            }
> +            if (o == NULL) {
> +                usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE, c->trans,
> +                                     0, 0, 0, 0);
> +            }
> +            if (o->format != FMT_ASSOCIATION) {
> +                usb_mtp_queue_result(s, RES_INVALID_PARENT_OBJECT, c->trans,
> +                                     0, 0, 0, 0);
> +            }
> +        }
> +        if (o) {
> +            s->dataset.parent_handle = o->handle;
> +        }
> +        s->data_out = usb_mtp_data_alloc(c);
> +        return;
>      case CMD_SEND_OBJECT:
>          if (!s->write_pending) {
>              usb_mtp_queue_result(s, RES_INVALID_OBJECTINFO,
> @@ -1492,6 +1555,19 @@ static void usb_mtp_cancel_packet(USBDevice *dev, USBPacket *p)
>      fprintf(stderr, "%s\n", __func__);
>  }
>  
> +static void utf16_to_str(uint8_t len, uint16_t *arr, char *name)
> +{
> +    int count;
> +    wchar_t *wstr = g_new0(wchar_t, len);
> +
> +    for (count = 0; count < len; count++) {
> +        wstr[count] = (wchar_t)arr[count];
> +    }
> +
> +    wcstombs(name, wstr, len);
> +    g_free(wstr);
> +}
> +
>  static void usb_mtp_write_data(MTPState *s)
>  {
>      MTPData *d = s->data_out;
> @@ -1565,6 +1641,45 @@ free:
>      s->write_pending = false;
>  }
>  
> +static void usb_mtp_write_metadata(MTPState *s)
> +{
> +    MTPData *d = s->data_out;
> +    ObjectInfo *dataset = (ObjectInfo *)d->data;
> +    char *filename = g_new0(char, dataset->length);
> +    MTPObject *o;
> +    MTPObject *p = usb_mtp_object_lookup(s, s->dataset.parent_handle);
> +    uint32_t next_handle = s->next_handle;
> +
> +    assert(!s->write_pending);
> +
> +    utf16_to_str(dataset->length, dataset->filename, filename);
> +
> +    o = usb_mtp_object_lookup_name(p, filename, dataset->length);
> +    if (o != NULL) {
> +        next_handle = o->handle;
> +    }
> +
> +    s->dataset.filename = filename;
> +    s->dataset.format = dataset->format;
> +    s->dataset.size = dataset->size;
> +    s->dataset.filename = filename;
> +    s->write_pending = true;
> +
> +    if (s->dataset.format == FMT_ASSOCIATION) {
> +        usb_mtp_write_data(s);
> +        /* next_handle will be allocated to the newly created dir */
> +        if (d->fd == -1) {
> +            usb_mtp_queue_result(s, RES_STORE_FULL, d->trans,
> +                                 0, 0, 0, 0);
> +            return;
> +        }
> +        d->fd = -1;
> +    }
> +
> +    usb_mtp_queue_result(s, RES_OK, d->trans, 3, QEMU_STORAGE_ID,
> +                         s->dataset.parent_handle, next_handle);
> +}
> +
>  static void usb_mtp_get_data(MTPState *s, mtp_container *container,
>                               USBPacket *p)
>  {
> @@ -1589,6 +1704,19 @@ static void usb_mtp_get_data(MTPState *s, mtp_container *container,
>      }
>  
>      switch (d->code) {
> +    case CMD_SEND_OBJECT_INFO:
> +        usb_packet_copy(p, d->data + d->offset, dlen);
> +        d->offset += dlen;
> +        if (d->offset == d->length) {
> +            /* The operation might have already failed */
> +            if (!s->result) {
> +                usb_mtp_write_metadata(s);
> +            }
> +            usb_mtp_data_free(s->data_out);
> +            s->data_out = NULL;
> +            return;
> +        }
> +        break;
>      case CMD_SEND_OBJECT:
>          usb_packet_copy(p, d->data + d->offset, dlen);
>          d->offset += dlen;
> -- 
> 2.14.3
> 
> 

Regards,
Daniel
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