Don't call UpdateLayerIDMap when creating a layer with no parent #1735
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I am fine with this change, I've tested it and seems to work well |
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LGTM |
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@mtrmac ready to go forward with this? |
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Yes, I think this makes sense to merge. |
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: giuseppe, mtrmac The full list of commands accepted by this bot can be found here. The pull request process is described here
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/hold |
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@mtrmac do you want to change the commit message or do we keep the "RFC:" tag there? |
rhatdan
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Should not change behavior. Signed-off-by: Miloslav Trmač <mitr@redhat.com>
AFAICS this call is intended to "remap" the parent layer's contents to the desired IDMappings; but when there is no parent layer, there is nothing to remap. Signed-off-by: Miloslav Trmač <mitr@redhat.com>
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Oops, fixed the commit title. Thanks. |
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/lgtm |
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Signed-off-by: Miloslav Trmač <mitr@redhat.com>
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After containers/storage#1735 , we don't need the conditional, so remove it. Signed-off-by: Miloslav Trmač <mitr@redhat.com>
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After containers/storage#1735 , we don't need the condition, so remove it. Signed-off-by: Miloslav Trmač <mitr@redhat.com>
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Signed-off-by: Miloslav Trmač <mitr@redhat.com>
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After containers/storage#1735 , we don't need the condition, so remove it. Signed-off-by: Miloslav Trmač <mitr@redhat.com>
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Warning: I don’t really know what I’m doing.
AFAICS this call is intended to "remap" the parent layer's contents to the desired IDMappings; but when there is no parent layer, there is nothing to remap.
Motivation: I’m trying to get c/image tests of c/storage working completely unprivileged.
On macOS that actually works out of the box (where some potentially relevant points are that after #811 ,
pkg/chrootarchivedoes not chroot on Darwin, and thatpkg/idtools.SafeChowndoes not really chown on Darwin).On Linux, the out-of-the-box setup starts initializing
vfsby chowning to (0, 0), and that fails. There is some pre-existing code in https://github.com/containers/image/blob/6bf0d1f0ae6682a5dd9a9d07d41f78be160d4383/storage/storage_test.go#L69-L78 to avoid that by remapping (“user-to-current”), and that part seems to work on Linux…… but with the “user-to-current” ID maps, on macOS, layer creation fails of the first (no-parent) layer fails, because the current logic gets the ID map from the new layer from the store’s configuration (”user-to-current”), but defaults the ID map of the (nonexistent) parent to empty, sees a difference, and triggers
UpdateLayerIDMap. And that tries to really chroot, and fails.(Ultimately, on Linux, layer extraction seems to always chroot, so I am failing with my overall goal. Anyway, this seems to be conceptually the right thing to do.)
So, this entirely avoids the
UpdateLayerIDMapcall. Again, warning: I don’t know what I’m doing.Some alternatives:
Store.PutLayersets the ID maps from its options; but the nonexistent-parent ID map is set to entirely empty. Instead,Store.PutLayercould calllayerStore.createwith new options providing the store’s ID map to use as the nonexistent-parent ID map value. That would have the same effect, except thatlayerStore.createwould think there is a “parent ID map”. I think that’s more invasive, and conceptually a bit less correct (there is no parent, so there is no parent ID map at all).UpdateLayerIDMapimplementation should follow in steps of Limited support for operating on images on macOS #811 and not chroot, even if it is called.@nalind @giuseppe PTAL