pm/pkg/install.go

201 lines
4.4 KiB
Go
Raw Normal View History

2018-03-03 21:28:24 -08:00
package pkg
import (
2018-03-04 00:50:13 -08:00
"archive/tar"
2018-03-04 00:54:48 -08:00
"bufio"
"crypto/sha256"
"fmt"
2018-03-03 22:52:01 -08:00
"io"
2018-03-04 00:50:13 -08:00
"log"
2018-03-03 22:52:01 -08:00
"net/http"
"os"
"path/filepath"
2018-03-04 00:54:48 -08:00
"strings"
2018-03-03 21:28:24 -08:00
"github.com/pkg/errors"
2018-03-03 22:52:01 -08:00
"mcquay.me/fs"
"mcquay.me/pm"
"mcquay.me/pm/db"
2018-03-04 00:50:13 -08:00
"mcquay.me/pm/keyring"
2018-03-03 21:28:24 -08:00
)
2018-03-03 22:52:01 -08:00
const cache = "var/cache/pm"
2018-03-03 21:28:24 -08:00
// Install fetches and installs pkgs from appropriate remotes.
func Install(root string, pkgs []string) error {
av, err := db.LoadAvailable(root)
if err != nil {
return errors.Wrap(err, "loading available db")
}
ms, err := av.Installable(pkgs)
if err != nil {
return errors.Wrap(err, "checking ability to install")
}
2018-03-03 22:52:01 -08:00
cacheDir := filepath.Join(root, cache)
if !fs.Exists(cacheDir) {
if err := os.MkdirAll(cacheDir, 0755); err != nil {
return errors.Wrap(err, "creating non-existent cache dir")
}
}
if !fs.IsDir(cacheDir) {
return errors.Errorf("%q is not a directory!", cacheDir)
}
2018-03-03 22:52:01 -08:00
if err := download(cacheDir, ms); err != nil {
return errors.Wrap(err, "downloading")
}
2018-03-04 00:50:13 -08:00
for _, m := range ms {
2018-03-04 00:54:48 -08:00
log.Printf("%+v", m)
2018-03-04 00:50:13 -08:00
if err := verifyManifestIntegrity(root, m); err != nil {
return errors.Wrap(err, "verifying pkg integrity")
}
2018-03-04 00:54:48 -08:00
if err := verifyPkgContents(root, m); err != nil {
return errors.Wrap(err, "verifying pkg contents")
}
2018-03-04 00:50:13 -08:00
}
2018-03-03 21:28:24 -08:00
return errors.New("NYI")
}
2018-03-03 22:52:01 -08:00
func download(cache string, ms pm.Metas) error {
// TODO (sm): concurrently fetch
for _, m := range ms {
resp, err := http.Get(m.URL())
if err != nil {
return errors.Wrap(err, "http get")
}
fn := filepath.Join(cache, m.Pkg())
f, err := os.Create(fn)
if err != nil {
return errors.Wrap(err, "creating")
}
if n, err := io.Copy(f, resp.Body); err != nil {
return errors.Wrapf(err, "copy %q to disk after %d bytes", m.URL(), n)
}
if err := resp.Body.Close(); err != nil {
return errors.Wrap(err, "closing resp body")
}
}
return nil
}
2018-03-04 00:50:13 -08:00
func verifyManifestIntegrity(root string, m pm.Meta) error {
pn := filepath.Join(root, cache, m.Pkg())
man, err := getReadCloser(pn, "manifest.sha256")
if err != nil {
return errors.Wrap(err, "getting manifest reader")
}
sig, err := getReadCloser(pn, "manifest.sha256.asc")
if err != nil {
return errors.Wrap(err, "getting manifest reader")
}
if err := keyring.Verify(root, man, sig); err != nil {
return errors.Wrap(err, "verifying manifest")
}
if err := man.Close(); err != nil {
return errors.Wrap(err, "closing manifest reader")
}
if err := sig.Close(); err != nil {
return errors.Wrap(err, "closing manifest signature reader")
}
return nil
}
2018-03-04 00:54:48 -08:00
func verifyPkgContents(root string, m pm.Meta) error {
pn := filepath.Join(root, cache, m.Pkg())
man, err := getReadCloser(pn, "manifest.sha256")
if err != nil {
return errors.Wrap(err, "getting manifest reader")
}
cs := map[string]string{}
s := bufio.NewScanner(man)
for s.Scan() {
elems := strings.Split(s.Text(), "\t")
if len(elems) != 2 {
return errors.Errorf("manifest format error; got %d elements, want 2", len(elems))
}
cs[elems[1]] = elems[0]
}
if err := man.Close(); err != nil {
return errors.Wrap(err, "closing manifest reader")
}
if err := s.Err(); err != nil {
return errors.Wrap(err, "scanning manifest")
}
pf, err := os.Open(pn)
if err != nil {
return errors.Wrap(err, "opening pkg file")
}
tr := tar.NewReader(pf)
for {
hdr, err := tr.Next()
if err == io.EOF {
break
}
if err != nil {
return errors.Wrap(err, "tar traversal")
}
if hdr.Name == "manifest.sha256" || hdr.Name == "manifest.sha256.asc" {
continue
}
if hdr.FileInfo().IsDir() {
continue
}
sha, ok := cs[hdr.Name]
if !ok {
return errors.Errorf("extra file %q found in tarfile!", hdr.Name)
}
sr := sha256.New()
if n, err := io.Copy(sr, tr); err != nil {
return errors.Wrapf(err, "calculating checksum after %v bytes", n)
}
if sha != fmt.Sprintf("%x", sr.Sum(nil)) {
return errors.Errorf("%q checksum was incorrect", hdr.Name)
}
}
return nil
}
2018-03-04 00:50:13 -08:00
type tarSlurper struct {
f *os.File
tr *tar.Reader
}
func (ts *tarSlurper) Close() error {
return ts.f.Close()
}
func (ts *tarSlurper) Read(p []byte) (int, error) {
return ts.tr.Read(p)
}
func getReadCloser(tn, fn string) (io.ReadCloser, error) {
pf, err := os.Open(tn)
if err != nil {
return nil, errors.Wrap(err, "opening pkg file")
}
tr := tar.NewReader(pf)
for {
hdr, err := tr.Next()
if err == io.EOF {
break
}
if err != nil {
return nil, errors.Wrap(err, "tar traversal")
}
if hdr.Name == fn {
return &tarSlurper{pf, tr}, nil
}
}
return nil, errors.Errorf("%q not found", fn)
}