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