On Mon, Sep 02, 2019 at 02:00:27PM -0300, jcfaracco@gmail.com wrote:
From: Julio Faracco <jcfaracco@gmail.com>
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@gmail.com> ---
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@redhat.com> and pushed to git Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|