On Mon, Sep 02, 2019 at 02:00:27PM -0300, jcfaracco@xxxxxxxxx wrote:
> From: Julio Faracco <jcfaracco@xxxxxxxxx>
>
> This is an issue for LXC loop devices when you are trying to get loop
> devices info using `ioctl`. Modern apps uses `/sys/dev/block` to grab
> information about devices, but if you use the method mention you won't
> be able to retrive the associated file with that loop device. See
> example below from cryptsetup sources:
>
> static char *_ioctl_backing_file(const char *loop)
> {
> struct loop_info64 lo64 = {0};
> int loop_fd;
>
> loop_fd = open(loop, O_RDONLY);
> if (loop_fd < 0)
> return NULL;
>
> if (ioctl(loop_fd, LOOP_GET_STATUS64, &lo64) < 0) {
> close(loop_fd);
> return NULL;
> }
>
> lo64.lo_file_name[LO_NAME_SIZE-2] = '*';
> lo64.lo_file_name[LO_NAME_SIZE-1] = 0;
>
> close(loop_fd);
> return strdup((char*)lo64.lo_file_name);
> }
>
> It will return an empty string because lo_file_name was not set.
> Function `virFileLoopDeviceOpenSearch()` is using `ioctl` to query data,
> but it is not checking `lo_file_name` field.
>
> v1: I accidentally committed two wrong lines.
This type of message should be put after the "---" lines...
>
> Signed-off-by: Julio Faracco <jcfaracco@xxxxxxxxx>
> ---
Here, so that it doesn't get into git history when the patch
is applied
> src/util/virfile.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
Reviewed-by: Daniel P. Berrangé <berrange@xxxxxxxxxx>
and pushed to git
Regards,
Daniel
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