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package buildah
import (
"bufio"
"io"
"os"
"strconv"
"strings"
"github.com/containers/storage/pkg/archive"
"github.com/containers/storage/pkg/chrootarchive"
"github.com/containers/storage/pkg/idtools"
"github.com/containers/storage/pkg/reexec"
rspec "github.com/opencontainers/runtime-spec/specs-go"
"github.com/pkg/errors"
)
// InitReexec is a wrapper for reexec.Init(). It should be called at
// the start of main(), and if it returns true, main() should return
// immediately.
func InitReexec() bool {
return reexec.Init()
}
func copyStringStringMap(m map[string]string) map[string]string {
n := map[string]string{}
for k, v := range m {
n[k] = v
}
return n
}
func copyStringSlice(s []string) []string {
t := make([]string, len(s))
copy(t, s)
return t
}
func stringInSlice(s string, slice []string) bool {
for _, v := range slice {
if v == s {
return true
}
}
return false
}
func convertStorageIDMaps(UIDMap, GIDMap []idtools.IDMap) ([]rspec.LinuxIDMapping, []rspec.LinuxIDMapping) {
uidmap := make([]rspec.LinuxIDMapping, 0, len(UIDMap))
gidmap := make([]rspec.LinuxIDMapping, 0, len(GIDMap))
for _, m := range UIDMap {
uidmap = append(uidmap, rspec.LinuxIDMapping{
HostID: uint32(m.HostID),
ContainerID: uint32(m.ContainerID),
Size: uint32(m.Size),
})
}
for _, m := range GIDMap {
gidmap = append(gidmap, rspec.LinuxIDMapping{
HostID: uint32(m.HostID),
ContainerID: uint32(m.ContainerID),
Size: uint32(m.Size),
})
}
return uidmap, gidmap
}
func convertRuntimeIDMaps(UIDMap, GIDMap []rspec.LinuxIDMapping) ([]idtools.IDMap, []idtools.IDMap) {
uidmap := make([]idtools.IDMap, 0, len(UIDMap))
gidmap := make([]idtools.IDMap, 0, len(GIDMap))
for _, m := range UIDMap {
uidmap = append(uidmap, idtools.IDMap{
HostID: int(m.HostID),
ContainerID: int(m.ContainerID),
Size: int(m.Size),
})
}
for _, m := range GIDMap {
gidmap = append(gidmap, idtools.IDMap{
HostID: int(m.HostID),
ContainerID: int(m.ContainerID),
Size: int(m.Size),
})
}
return uidmap, gidmap
}
// copyFileWithTar returns a function which copies a single file from outside
// of any container into our working container, mapping permissions using the
// container's ID maps, possibly overridden using the passed-in chownOpts
func (b *Builder) copyFileWithTar(chownOpts *idtools.IDPair) func(src, dest string) error {
convertedUIDMap, convertedGIDMap := convertRuntimeIDMaps(b.IDMappingOptions.UIDMap, b.IDMappingOptions.GIDMap)
untarMappings := idtools.NewIDMappingsFromMaps(convertedUIDMap, convertedGIDMap)
archiver := chrootarchive.NewArchiverWithChown(nil, chownOpts, untarMappings)
return archiver.CopyFileWithTar
}
// copyWithTar returns a function which copies a directory tree from outside of
// any container into our working container, mapping permissions using the
// container's ID maps, possibly overridden using the passed-in chownOpts
func (b *Builder) copyWithTar(chownOpts *idtools.IDPair) func(src, dest string) error {
convertedUIDMap, convertedGIDMap := convertRuntimeIDMaps(b.IDMappingOptions.UIDMap, b.IDMappingOptions.GIDMap)
untarMappings := idtools.NewIDMappingsFromMaps(convertedUIDMap, convertedGIDMap)
archiver := chrootarchive.NewArchiverWithChown(nil, chownOpts, untarMappings)
return archiver.CopyWithTar
}
// untarPath returns a function which extracts an archive in a specified
// location into our working container, mapping permissions using the
// container's ID maps, possibly overridden using the passed-in chownOpts
func (b *Builder) untarPath(chownOpts *idtools.IDPair) func(src, dest string) error {
convertedUIDMap, convertedGIDMap := convertRuntimeIDMaps(b.IDMappingOptions.UIDMap, b.IDMappingOptions.GIDMap)
untarMappings := idtools.NewIDMappingsFromMaps(convertedUIDMap, convertedGIDMap)
archiver := chrootarchive.NewArchiverWithChown(nil, chownOpts, untarMappings)
return archiver.UntarPath
}
// tarPath returns a function which creates an archive of a specified
// location in the container's filesystem, mapping permissions using the
// container's ID maps
func (b *Builder) tarPath() func(path string) (io.ReadCloser, error) {
convertedUIDMap, convertedGIDMap := convertRuntimeIDMaps(b.IDMappingOptions.UIDMap, b.IDMappingOptions.GIDMap)
tarMappings := idtools.NewIDMappingsFromMaps(convertedUIDMap, convertedGIDMap)
return func(path string) (io.ReadCloser, error) {
return archive.TarWithOptions(path, &archive.TarOptions{
Compression: archive.Uncompressed,
UIDMaps: tarMappings.UIDs(),
GIDMaps: tarMappings.GIDs(),
})
}
}
// getProcIDMappings reads mappings from the named node under /proc.
func getProcIDMappings(path string) ([]rspec.LinuxIDMapping, error) {
var mappings []rspec.LinuxIDMapping
f, err := os.Open(path)
if err != nil {
return nil, errors.Wrapf(err, "error reading ID mappings from %q", path)
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
line := scanner.Text()
fields := strings.Fields(line)
if len(fields) != 3 {
return nil, errors.Errorf("line %q from %q has %d fields, not 3", line, path, len(fields))
}
cid, err := strconv.ParseUint(fields[0], 10, 32)
if err != nil {
return nil, errors.Wrapf(err, "error parsing container ID value %q from line %q in %q", fields[0], line, path)
}
hid, err := strconv.ParseUint(fields[1], 10, 32)
if err != nil {
return nil, errors.Wrapf(err, "error parsing host ID value %q from line %q in %q", fields[1], line, path)
}
size, err := strconv.ParseUint(fields[2], 10, 32)
if err != nil {
return nil, errors.Wrapf(err, "error parsing size value %q from line %q in %q", fields[2], line, path)
}
mappings = append(mappings, rspec.LinuxIDMapping{ContainerID: uint32(cid), HostID: uint32(hid), Size: uint32(size)})
}
return mappings, nil
}
// getHostIDs uses ID mappings to compute the host-level IDs that will
// correspond to a UID/GID pair in the container.
func getHostIDs(uidmap, gidmap []rspec.LinuxIDMapping, uid, gid uint32) (uint32, uint32, error) {
uidMapped := true
for _, m := range uidmap {
uidMapped = false
if uid >= m.ContainerID && uid < m.ContainerID+m.Size {
uid = (uid - m.ContainerID) + m.HostID
uidMapped = true
break
}
}
if !uidMapped {
return 0, 0, errors.Errorf("container uses ID mappings, but doesn't map UID %d", uid)
}
gidMapped := true
for _, m := range gidmap {
gidMapped = false
if gid >= m.ContainerID && gid < m.ContainerID+m.Size {
gid = (gid - m.ContainerID) + m.HostID
gidMapped = true
break
}
}
if !gidMapped {
return 0, 0, errors.Errorf("container uses ID mappings, but doesn't map GID %d", gid)
}
return uid, gid, nil
}
// getHostRootIDs uses ID mappings in spec to compute the host-level IDs that will
// correspond to UID/GID 0/0 in the container.
func getHostRootIDs(spec *rspec.Spec) (uint32, uint32, error) {
if spec.Linux == nil {
return 0, 0, nil
}
return getHostIDs(spec.Linux.UIDMappings, spec.Linux.GIDMappings, 0, 0)
}
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