pm/pkg/install.go
2018-03-05 23:43:42 -08:00

335 lines
8.0 KiB
Go

package pkg
import (
"archive/tar"
"bufio"
"compress/bzip2"
"crypto/sha256"
"fmt"
"io"
"io/ioutil"
"net/http"
"os"
"os/exec"
"path/filepath"
"strings"
"github.com/pkg/errors"
"mcquay.me/fs"
"mcquay.me/pm"
"mcquay.me/pm/db"
"mcquay.me/pm/keyring"
)
const cache = "var/cache/pm"
const installed = "var/lib/pm/installed"
// 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")
}
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)
}
installedDir := filepath.Join(root, installed)
if !fs.Exists(installedDir) {
if err := os.MkdirAll(installedDir, 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)
}
if err := download(cacheDir, ms); err != nil {
return errors.Wrap(err, "downloading")
}
for _, m := range ms {
if err := verifyManifestIntegrity(root, m); err != nil {
return errors.Wrap(err, "verifying pkg integrity")
}
if err := expandPkgContents(root, m); err != nil {
if err := os.RemoveAll(filepath.Join(root, installed, string(m.Name))); err != nil {
err = errors.Wrap(err, "cleaning up")
}
return errors.Wrap(err, "verifying pkg contents")
}
if err := script(root, m, "pre-install"); err != nil {
return errors.Wrap(err, "pre-install")
}
if err := expandRoot(root, m); err != nil {
return errors.Wrap(err, "root expansion")
}
if err := script(root, m, "post-install"); err != nil {
return errors.Wrap(err, "pre-install")
}
if err := os.Remove(filepath.Join(cacheDir, m.Pkg())); err != nil {
return errors.Wrapf(err, "cleaning up pkg %v", m.Pkg())
}
}
return nil
}
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
}
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
}
func expandPkgContents(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")
}
ip := filepath.Join(root, installed, string(m.Name))
if err := os.MkdirAll(ip, 0755); err != nil {
return errors.Wrapf(err, "making install dir for %q", m.Name)
}
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() {
if hdr.Name != "bin" {
return errors.Errorf("%v is unexpected", hdr.Name)
}
if err := os.MkdirAll(filepath.Join(ip, hdr.Name), hdr.FileInfo().Mode()); err != nil {
return errors.Wrapf(err, "mkdir for %v", hdr.Name)
}
continue
}
sha, ok := cs[hdr.Name]
if !ok {
return errors.Errorf("extra file %q found in tarfile!", hdr.Name)
}
name := filepath.Join(ip, hdr.Name)
sr := sha256.New()
var o io.WriteCloser
o = close{ioutil.Discard}
if hdr.Name != "root.tar.bz2" {
f, err := os.OpenFile(filepath.Join(ip, hdr.Name), os.O_WRONLY|os.O_CREATE, hdr.FileInfo().Mode())
if err != nil {
return errors.Wrap(err, "open file in install dir")
}
o = f
}
w := io.MultiWriter(o, sr)
if n, err := io.Copy(w, tr); err != nil {
return errors.Wrapf(err, "copying file %q after %v bytes", hdr.Name, n)
}
if sha != fmt.Sprintf("%x", sr.Sum(nil)) {
return errors.Errorf("%q checksum was incorrect", hdr.Name)
}
if err := o.Close(); err != nil {
return errors.Wrapf(err, "closing %v", name)
}
}
return nil
}
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)
}
// close should be used to wrap ioutil.Discard to give it a noop Close method.
type close struct {
io.Writer
}
func (close) Close() error {
return nil
}
func script(root string, m pm.Meta, name string) error {
bin := filepath.Join(root, installed, string(m.Name), "bin", name)
if !fs.Exists(bin) {
return nil
}
cmd := exec.Command(bin)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
return cmd.Run()
}
func expandRoot(root string, m pm.Meta) error {
bomn := filepath.Join(root, installed, string(m.Name), "bom.sha256")
bf, err := os.Open(bomn)
if err != nil {
return errors.Wrap(err, "opening bom")
}
cs := map[string]string{}
s := bufio.NewScanner(bf)
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]
}
pn := filepath.Join(root, cache, m.Pkg())
tbz, err := getReadCloser(pn, "root.tar.bz2")
if err != nil {
return errors.Wrap(err, "getting root.tar.bz2 reader")
}
tr := tar.NewReader(bzip2.NewReader(tbz))
for {
hdr, err := tr.Next()
if err == io.EOF {
break
}
if err != nil {
return errors.Wrap(err, "tar traversal")
}
if hdr.FileInfo().IsDir() {
d := filepath.Join(root, hdr.Name)
if err := os.MkdirAll(d, hdr.FileInfo().Mode()); err != nil {
return errors.Wrapf(err, "making directory %q", d)
}
continue
}
f, err := os.OpenFile(filepath.Join(root, hdr.Name), os.O_WRONLY|os.O_CREATE, hdr.FileInfo().Mode())
if err != nil {
return errors.Wrapf(err, "open output file %q", hdr.Name)
}
if n, err := io.Copy(f, tr); err != nil {
return errors.Wrapf(err, "copy file %q after %v bytes", hdr.Name, n)
}
if err := f.Close(); err != nil {
return errors.Wrapf(err, "closing %q", hdr.Name)
}
}
return nil
}