[Spice-devel] [PATCH spice-vdagent v6 1/2] file-xfer: Check free space before file transfer

Victor Toso victortoso at redhat.com
Thu Jun 1 09:04:04 UTC 2017


Hi,

On Wed, May 24, 2017 at 05:01:38PM +0200, Jakub Janků wrote:
> Add function get_free_space_available that retrieves amount of free
> space in the given directory. The statvfs may fail even when there's
> enough free space (e.g. when not supported by system), in this case
> return G_MAXUINT64 so that the transfer isn't terminated groundlessly.
>
> When the file is too big, send VDAgentFileXferStatusMessage with
> result VD_AGENT_FILE_XFER_STATUS_NOT_ENOUGH_SPACE and amount of free
> space available, if the result isn't supported by client, send
> VD_AGENT_FILE_XFER_STATUS_ERROR. Client then terminates the transfer.
>
> Change send_file_xfer_status() to support sending file xfer status
> messages with additional (error) data, can be used for reporting
> more file xfer errors.
> ---
>  src/vdagent/file-xfers.c | 40 ++++++++++++++++++++++++++++++
>  src/vdagentd/vdagentd.c  | 64 ++++++++++++++++++++++++++++++++----------------
>  2 files changed, 83 insertions(+), 21 deletions(-)
>
> diff --git a/src/vdagent/file-xfers.c b/src/vdagent/file-xfers.c
> index b3937a4..51fccd7 100644
> --- a/src/vdagent/file-xfers.c
> +++ b/src/vdagent/file-xfers.c
> @@ -32,6 +32,7 @@
>  #include <fcntl.h>
>  #include <errno.h>
>  #include <sys/stat.h>
> +#include <sys/statvfs.h>
>  #include <sys/types.h>
>  #include <spice/vd_agent.h>
>  #include <glib.h>
> @@ -168,6 +169,17 @@ error:
>      return NULL;
>  }
>
> +static uint64_t get_free_space_available(const char *path)
> +{
> +    struct statvfs stat;
> +    if (statvfs(path, &stat) != 0) {
> +        syslog(LOG_WARNING, "file-xfer: failed to get free space, statvfs error: %s",
> +               strerror(errno));
> +        return G_MAXUINT64;
> +    }
> +    return stat.f_bsize * stat.f_bavail;
> +}
> +
>  void vdagent_file_xfers_start(struct vdagent_file_xfers *xfers,
>      VDAgentFileXferStartMessage *msg)
>  {
> @@ -175,6 +187,7 @@ void vdagent_file_xfers_start(struct vdagent_file_xfers *xfers,
>      char *dir = NULL, *path = NULL, *file_path = NULL;
>      struct stat st;
>      int i;
> +    uint64_t free_space;
>
>      g_return_if_fail(xfers != NULL);
>
> @@ -193,6 +206,33 @@ void vdagent_file_xfers_start(struct vdagent_file_xfers *xfers,
>
>      file_path = g_build_filename(xfers->save_dir, task->file_name, NULL);
>
> +    free_space = get_free_space_available(xfers->save_dir);
> +    if (task->file_size > free_space) {
> +        gchar *free_space_str, *file_size_str;
> +#if GLIB_CHECK_VERSION(2, 30, 0)
> +        free_space_str = g_format_size(free_space);
> +        file_size_str = g_format_size(task->file_size);
> +#else
> +        free_space_str = g_format_size_for_display(free_space);
> +        file_size_str = g_format_size_for_display(task->file_size);
> +#endif
> +        syslog(LOG_ERR, "file-xfer: not enough free space (%s to copy, %s free)",
> +               file_size_str, free_space_str);
> +        g_free(free_space_str);
> +        g_free(file_size_str);
> +
> +        udscs_write(xfers->vdagentd,
> +                    VDAGENTD_FILE_XFER_STATUS,
> +                    msg->id,
> +                    VD_AGENT_FILE_XFER_STATUS_NOT_ENOUGH_SPACE,
> +                    (uint8_t *)&free_space,
> +                    sizeof(free_space));
> +        vdagent_file_xfer_task_free(task);
> +        g_free(file_path);
> +        g_free(dir);
> +        return;
> +    }
> +
>      dir = g_path_get_dirname(file_path);
>      if (g_mkdir_with_parents(dir, S_IRWXU) == -1) {
>          syslog(LOG_ERR, "file-xfer: Failed to create dir %s", dir);
> diff --git a/src/vdagentd/vdagentd.c b/src/vdagentd/vdagentd.c
> index f3ac606..d647fab 100644
> --- a/src/vdagentd/vdagentd.c
> +++ b/src/vdagentd/vdagentd.c
> @@ -301,20 +301,38 @@ static void do_client_clipboard(struct vdagent_virtio_port *vport,
>                  data, size);
>  }
>
> -/* To be used by vdagentd for failures in file-xfer such as when file-xfer was
> - * cancelled or an error happened */
> +/* Send file-xfer status to the client. In the case status is an error,
> + * optional data for the client and log message may be specified. */
>  static void send_file_xfer_status(struct vdagent_virtio_port *vport,
> -                                  const char *msg, uint32_t id, uint32_t xfer_status)
> +                                  const char *msg, uint32_t id, uint32_t xfer_status,
> +                                  const uint8_t *data, uint32_t data_size)
>  {
> -    VDAgentFileXferStatusMessage status = {
> -        .id = GUINT32_TO_LE(id),
> -        .result = GUINT32_TO_LE(xfer_status),
> -    };
> -    syslog(LOG_WARNING, msg, id);
> +    VDAgentFileXferStatusMessage *status;
> +
> +    /* Replace new detailed errors with older generic VD_AGENT_FILE_XFER_STATUS_ERROR
> +     * when not supported by client */
> +    if (xfer_status > VD_AGENT_FILE_XFER_STATUS_SUCCESS &&
> +        !VD_AGENT_HAS_CAPABILITY(capabilities, capabilities_size,
> +                                VD_AGENT_CAP_FILE_XFER_DETAILED_ERRORS)) {
> +        xfer_status = VD_AGENT_FILE_XFER_STATUS_ERROR;
> +        data_size = 0;
> +    }
> +
> +    status = malloc(sizeof(*status) + data_size);
> +    status->id = GUINT32_TO_LE(id);
> +    status->result = GUINT32_TO_LE(xfer_status);
> +    if (data)
> +        memcpy(status->data, data, data_size);

So, data here will be a uint64_t, the free space. You will need to
convert it to little endian. As `uint8_t *data` is a bit generic per
_xfer_detailed_errors, it is better to request this to be converted to
LE before calling send_file_xfer_status(). Maybe you can do it on
agent_read_complete() to keep the changes related to endianess in
vdagentd as much as possible (using GUINT64_TO_LE())

> @@ -175,6 +187,7 @@ void vdagent_file_xfers_start(struct vdagent_file_xfers *xfers,
>      char *dir = NULL, *path = NULL, *file_path = NULL;
>      struct stat st;
>      int i;

> +
> +    if (msg)
> +        syslog(LOG_WARNING, msg, id);
> +
>      if (vport)
>          vdagent_virtio_port_write(vport, VDP_CLIENT_PORT,
>                                    VD_AGENT_FILE_XFER_STATUS, 0,
> -                                  (uint8_t *)&status, sizeof(status));
> +                                  (uint8_t *)status, sizeof(*status) + data_size);
> +
> +    free(status);
>  }
>
>  static void do_client_file_xfer(struct vdagent_virtio_port *vport,
> @@ -331,14 +349,14 @@ static void do_client_file_xfer(struct vdagent_virtio_port *vport,
>              send_file_xfer_status(vport,
>                 "Could not find an agent connection belonging to the "
>                 "active session, cancelling client file-xfer request %u",
> -               s->id, VD_AGENT_FILE_XFER_STATUS_CANCELLED);
> +               s->id, VD_AGENT_FILE_XFER_STATUS_CANCELLED, NULL, 0);
>              return;
>          } else if (session_info_session_is_locked(session_info)) {
>              syslog(LOG_DEBUG, "Session is locked, skipping file-xfer-start");
>              send_file_xfer_status(vport,
>                 "User's session is locked and cannot start file transfer. "
>                 "Cancelling client file-xfer request %u",
> -               s->id, VD_AGENT_FILE_XFER_STATUS_ERROR);
> +               s->id, VD_AGENT_FILE_XFER_STATUS_ERROR, NULL, 0);
>              return;
>          }
>          udscs_write(active_session_conn, VDAGENTD_FILE_XFER_START, 0, 0,
> @@ -810,7 +828,7 @@ static gboolean remove_active_xfers(gpointer key, gpointer value, gpointer conn)
>          send_file_xfer_status(virtio_port,
>                                "Agent disc; cancelling file-xfer %u",
>                                GPOINTER_TO_UINT(key),
> -                              VD_AGENT_FILE_XFER_STATUS_CANCELLED);
> +                              VD_AGENT_FILE_XFER_STATUS_CANCELLED, NULL, 0);
>          return 1;
>      } else
>          return 0;
> @@ -903,17 +921,21 @@ static void agent_read_complete(struct udscs_connection **connp,
>          }
>          break;
>      case VDAGENTD_FILE_XFER_STATUS:{
> -        VDAgentFileXferStatusMessage status;
> -        status.id = GUINT32_TO_LE(header->arg1);
> -        status.result = GUINT32_TO_LE(header->arg2);
> -        vdagent_virtio_port_write(virtio_port, VDP_CLIENT_PORT,
> -                                  VD_AGENT_FILE_XFER_STATUS, 0,
> -                                  (uint8_t *)&status, sizeof(status));
> -        if (status.result == VD_AGENT_FILE_XFER_STATUS_CAN_SEND_DATA)
> -            g_hash_table_insert(active_xfers, GUINT_TO_POINTER(status.id),
> +        /* header->arg1 = file xfer task id, header->arg2 = file xfer status */
> +        switch (header->arg2) {
> +            case VD_AGENT_FILE_XFER_STATUS_NOT_ENOUGH_SPACE:
> +                send_file_xfer_status(virtio_port, "Not enough free space. Cancelling file-xfer %u",
> +                                      header->arg1, header->arg2, data, sizeof(uint64_t));
> +                break;
> +            default:
> +                send_file_xfer_status(virtio_port, NULL, header->arg1, header->arg2, NULL, 0);
> +        }
> +
> +        if (header->arg2 == VD_AGENT_FILE_XFER_STATUS_CAN_SEND_DATA)
> +            g_hash_table_insert(active_xfers, GUINT_TO_POINTER(GUINT32_TO_LE(header->arg1)),
>                                  *connp);

Sorry if i missed this before in early reviews. Do you mind splitting
this chunk in two patches? One will be an intermediary patch to make you
use send_file_xfer_status() here, using header->arg1 and header->arg2 as
parameters.

The *msg could be NULL which means you will also need to add the current
if (msg) { syslog(LOG_WARNING, msg, id); } in send_file_xfer_status()

With this preparatory patch, the change related to  check-free-space
will be more clear.

Cheers!

>          else
> -            g_hash_table_remove(active_xfers, GUINT_TO_POINTER(status.id));
> +            g_hash_table_remove(active_xfers, GUINT_TO_POINTER(GUINT32_TO_LE(header->arg1)));
>          break;
>      }
>
> -- 
> 2.13.0
> 
> _______________________________________________
> Spice-devel mailing list
> Spice-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/spice-devel
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