88 lines
2.1 KiB
Go
88 lines
2.1 KiB
Go
package oci
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import (
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"bytes"
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"context"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"github.com/docker/docker/pkg/idtools"
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"github.com/moby/buildkit/executor"
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"github.com/moby/buildkit/identity"
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"github.com/pkg/errors"
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)
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const defaultHostname = "buildkitsandbox"
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func GetHostsFile(ctx context.Context, stateDir string, extraHosts []executor.HostIP, idmap *idtools.IdentityMapping, hostname string) (string, func(), error) {
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if len(extraHosts) != 0 || hostname != defaultHostname {
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return makeHostsFile(stateDir, extraHosts, idmap, hostname)
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}
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_, err := g.Do(ctx, stateDir, func(ctx context.Context) (interface{}, error) {
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_, _, err := makeHostsFile(stateDir, nil, idmap, hostname)
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return nil, err
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})
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if err != nil {
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return "", nil, err
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}
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return filepath.Join(stateDir, "hosts"), func() {}, nil
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}
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func makeHostsFile(stateDir string, extraHosts []executor.HostIP, idmap *idtools.IdentityMapping, hostname string) (string, func(), error) {
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p := filepath.Join(stateDir, "hosts")
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if len(extraHosts) != 0 || hostname != defaultHostname {
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p += "." + identity.NewID()
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}
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_, err := os.Stat(p)
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if err == nil {
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return "", func() {}, nil
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}
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if !errors.Is(err, os.ErrNotExist) {
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return "", nil, err
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}
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b := &bytes.Buffer{}
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if _, err := b.Write([]byte(initHostsFile(hostname))); err != nil {
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return "", nil, err
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}
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for _, h := range extraHosts {
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if _, err := b.Write([]byte(fmt.Sprintf("%s\t%s\n", h.IP.String(), h.Host))); err != nil {
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return "", nil, err
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}
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}
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tmpPath := p + ".tmp"
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if err := ioutil.WriteFile(tmpPath, b.Bytes(), 0644); err != nil {
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return "", nil, err
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}
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if idmap != nil {
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root := idmap.RootPair()
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if err := os.Chown(tmpPath, root.UID, root.GID); err != nil {
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return "", nil, err
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}
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}
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if err := os.Rename(tmpPath, p); err != nil {
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return "", nil, err
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}
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return p, func() {
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os.RemoveAll(p)
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}, nil
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}
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func initHostsFile(hostname string) string {
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var hosts string
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if hostname != "" {
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hosts = fmt.Sprintf("127.0.0.1 localhost %s", hostname)
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} else {
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hosts = fmt.Sprintf("127.0.0.1 localhost %s", defaultHostname)
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}
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hosts = fmt.Sprintf("%s\n::1 localhost ip6-localhost ip6-loopback\n", hosts)
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return hosts
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}
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