Automatically update default offset

[rossburton]

If I want to build a disk image without a partition table which is several pieces of data glued together without a partition table I need to maintain the offsets for every partition by hand. This is because the offset automatically being the end of the previous partition only works for partitions which are in the partition table.

Can this auto-offset logic work for all images, and not just ones with a partition table?

[michaelolbrich]

If you set partition-table-type to none then you could just pretend that all partitions are in the partition table (which does not exist, so it doesn't matter). Then the offset will be calculated automatically. If you don't want any gaps at all, then you should also set align to 1.

[rossburton]

Like this?

image pack.img {
    hdimage {
        partition-table-type = "none"
    }
    partition 1 {
        image = "1"
    }
    partition 2 {
        image = "2"
    }
    partition 3 {
        image = "3"
    }
}

ERROR: hdimage(pack.img): partition 2 (offset 0x0, size 0xc) overlaps previous partition 1 (offset 0x0, size 0xc)

(new to genimage, may be doing something dumb)

[michaelolbrich]

Ah, we overwrite the in-partition-table flag when there is no partition table: https://github.com/pengutronix/genimage/blob/master/image-hd.c#L680

And I suppose that's correct that way: The default alignment for in-partition-table = true only makes sense on regular disk image with a normal sector size. When you use it for something else then a default alignment doesn't make sense.

So I'm not sure what the best way to fix this is. Probably just do auto offset for all partitions when no partition table is generated.