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https://github.com/token2/snapd.git
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3de3d65923
When a gadget is installed, we compare the previous gadget to detect removed files and remove them. Preserved files that are removed from content list are kept. This is important to be able to remove old boot firmware since some, like shim, change behavior depending of files that are present. This does not support directories. If the gadget install directories with content, the files in the directories will not be removed.
126 lines
4.0 KiB
Go
126 lines
4.0 KiB
Go
// -*- Mode: Go; indent-tabs-mode: t -*-
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/*
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* Copyright (C) 2014-2022 Canonical Ltd
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 3 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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package image
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// TODO: put these in appropriate package(s) once they are clarified a bit more
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import (
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"fmt"
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"os"
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"path/filepath"
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"github.com/snapcore/snapd/asserts"
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"github.com/snapcore/snapd/asserts/snapasserts"
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"github.com/snapcore/snapd/gadget"
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"github.com/snapcore/snapd/release"
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"github.com/snapcore/snapd/snap"
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)
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// FetchAndCheckSnapAssertions fetches and cross checks the snap assertions
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// matching the given snap file using the provided asserts.Fetcher and
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// assertion database.
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// The optional model assertion must be passed for full cross checks.
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func FetchAndCheckSnapAssertions(snapPath string, info *snap.Info, model *asserts.Model, f asserts.Fetcher, db asserts.RODatabase) (*asserts.SnapDeclaration, error) {
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sha3_384, size, err := asserts.SnapFileSHA3_384(snapPath)
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if err != nil {
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return nil, err
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}
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expectedProv := info.Provenance()
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// this assumes series "16"
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if err := snapasserts.FetchSnapAssertions(f, sha3_384, expectedProv); err != nil {
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return nil, fmt.Errorf("cannot fetch snap signatures/assertions: %v", err)
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}
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// cross checks
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verifiedRev, err := snapasserts.CrossCheck(info.InstanceName(), sha3_384, expectedProv, size, &info.SideInfo, model, db)
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if err != nil {
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return nil, err
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}
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if err := snapasserts.CheckProvenanceWithVerifiedRevision(snapPath, verifiedRev); err != nil {
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return nil, err
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}
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a, err := db.Find(asserts.SnapDeclarationType, map[string]string{
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"series": release.Series,
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"snap-id": info.SnapID,
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})
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if err != nil {
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return nil, fmt.Errorf("internal error: lost snap declaration for %q: %v", info.InstanceName(), err)
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}
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return a.(*asserts.SnapDeclaration), nil
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}
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// var so that it can be mocked for tests
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var writeResolvedContent = writeResolvedContentImpl
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// writeResolvedContent takes gadget.Info and the unpacked
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// gadget/kernel snaps and outputs the resolved content from the
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// {gadget,kernel}.yaml into a filesystem tree with the structure:
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// <prepareImageDir>/resolved-content/<volume-name>/part<structure-nr>/...
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//
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// E.g.
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// /tmp/prep-img/resolved-content/pi/part0/{config.txt,bootcode.bin,...}
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func writeResolvedContentImpl(prepareDir string, info *gadget.Info, gadgetUnpackDir, kernelUnpackDir string) error {
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fullPrepareDir, err := filepath.Abs(prepareDir)
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if err != nil {
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return err
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}
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targetDir := filepath.Join(fullPrepareDir, "resolved-content")
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opts := &gadget.LayoutOptions{
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GadgetRootDir: gadgetUnpackDir,
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KernelRootDir: kernelUnpackDir,
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}
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for volName, vol := range info.Volumes {
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pvol, err := gadget.LayoutVolume(vol, gadget.OnDiskStructsFromGadget(vol), opts)
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if err != nil {
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return err
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}
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for i, ps := range pvol.LaidOutStructure {
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if !ps.HasFilesystem() {
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continue
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}
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mw, err := gadget.NewMountedFilesystemWriter(nil, &ps, nil)
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if err != nil {
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return err
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}
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// ubuntu-image uses the "part{}" nomenclature
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dst := filepath.Join(targetDir, volName, fmt.Sprintf("part%d", i))
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// on UC20, ensure system-seed links back to the
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// <PrepareDir>/system-seed
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if ps.Role() == gadget.SystemSeed {
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uc20systemSeedDir := filepath.Join(fullPrepareDir, "system-seed")
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if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
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return err
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}
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if err := os.Symlink(uc20systemSeedDir, dst); err != nil {
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return err
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}
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}
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if err := mw.Write(dst, nil); err != nil {
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return err
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}
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}
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}
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return nil
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}
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