summaryrefslogtreecommitdiffhomepage
path: root/cmd/nardump/nardump.go
diff options
context:
space:
mode:
Diffstat (limited to 'cmd/nardump/nardump.go')
-rw-r--r--cmd/nardump/nardump.go368
1 files changed, 184 insertions, 184 deletions
diff --git a/cmd/nardump/nardump.go b/cmd/nardump/nardump.go
index 05be7b65a..241475537 100644
--- a/cmd/nardump/nardump.go
+++ b/cmd/nardump/nardump.go
@@ -1,184 +1,184 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-// nardump is like nix-store --dump, but in Go, writing a NAR
-// file (tar-like, but focused on being reproducible) to stdout
-// or to a hash with the --sri flag.
-//
-// It lets us calculate a Nix sha256 without the person running
-// git-pull-oss.sh having Nix available.
-package main
-
-// For the format, see:
-// See https://gist.github.com/jbeda/5c79d2b1434f0018d693
-
-import (
- "bufio"
- "crypto/sha256"
- "encoding/base64"
- "encoding/binary"
- "flag"
- "fmt"
- "io"
- "io/fs"
- "log"
- "os"
- "path"
- "sort"
-)
-
-var sri = flag.Bool("sri", false, "print SRI")
-
-func main() {
- flag.Parse()
- if flag.NArg() != 1 {
- log.Fatal("usage: nardump <dir>")
- }
- arg := flag.Arg(0)
- if err := os.Chdir(arg); err != nil {
- log.Fatal(err)
- }
- if *sri {
- hash := sha256.New()
- if err := writeNAR(hash, os.DirFS(".")); err != nil {
- log.Fatal(err)
- }
- fmt.Printf("sha256-%s\n", base64.StdEncoding.EncodeToString(hash.Sum(nil)))
- return
- }
- bw := bufio.NewWriter(os.Stdout)
- if err := writeNAR(bw, os.DirFS(".")); err != nil {
- log.Fatal(err)
- }
- bw.Flush()
-}
-
-// writeNARError is a sentinel panic type that's recovered by writeNAR
-// and converted into the wrapped error.
-type writeNARError struct{ err error }
-
-// narWriter writes NAR files.
-type narWriter struct {
- w io.Writer
- fs fs.FS
-}
-
-// writeNAR writes a NAR file to w from the root of fs.
-func writeNAR(w io.Writer, fs fs.FS) (err error) {
- defer func() {
- if e := recover(); e != nil {
- if we, ok := e.(writeNARError); ok {
- err = we.err
- return
- }
- panic(e)
- }
- }()
- nw := &narWriter{w: w, fs: fs}
- nw.str("nix-archive-1")
- return nw.writeDir(".")
-}
-
-func (nw *narWriter) writeDir(dirPath string) error {
- ents, err := fs.ReadDir(nw.fs, dirPath)
- if err != nil {
- return err
- }
- sort.Slice(ents, func(i, j int) bool {
- return ents[i].Name() < ents[j].Name()
- })
- nw.str("(")
- nw.str("type")
- nw.str("directory")
- for _, ent := range ents {
- nw.str("entry")
- nw.str("(")
- nw.str("name")
- nw.str(ent.Name())
- nw.str("node")
- mode := ent.Type()
- sub := path.Join(dirPath, ent.Name())
- var err error
- switch {
- case mode.IsRegular():
- err = nw.writeRegular(sub)
- case mode.IsDir():
- err = nw.writeDir(sub)
- default:
- // TODO(bradfitz): symlink, but requires fighting io/fs a bit
- // to get at Readlink or the osFS via fs. But for now
- // we don't need symlinks because they're not in Go's archive.
- return fmt.Errorf("unsupported file type %v at %q", sub, mode)
- }
- if err != nil {
- return err
- }
- nw.str(")")
- }
- nw.str(")")
- return nil
-}
-
-func (nw *narWriter) writeRegular(path string) error {
- nw.str("(")
- nw.str("type")
- nw.str("regular")
- fi, err := fs.Stat(nw.fs, path)
- if err != nil {
- return err
- }
- if fi.Mode()&0111 != 0 {
- nw.str("executable")
- nw.str("")
- }
- contents, err := fs.ReadFile(nw.fs, path)
- if err != nil {
- return err
- }
- nw.str("contents")
- if err := writeBytes(nw.w, contents); err != nil {
- return err
- }
- nw.str(")")
- return nil
-}
-
-func (nw *narWriter) str(s string) {
- if err := writeString(nw.w, s); err != nil {
- panic(writeNARError{err})
- }
-}
-
-func writeString(w io.Writer, s string) error {
- var buf [8]byte
- binary.LittleEndian.PutUint64(buf[:], uint64(len(s)))
- if _, err := w.Write(buf[:]); err != nil {
- return err
- }
- if _, err := io.WriteString(w, s); err != nil {
- return err
- }
- return writePad(w, len(s))
-}
-
-func writeBytes(w io.Writer, b []byte) error {
- var buf [8]byte
- binary.LittleEndian.PutUint64(buf[:], uint64(len(b)))
- if _, err := w.Write(buf[:]); err != nil {
- return err
- }
- if _, err := w.Write(b); err != nil {
- return err
- }
- return writePad(w, len(b))
-}
-
-func writePad(w io.Writer, n int) error {
- pad := n % 8
- if pad == 0 {
- return nil
- }
- var zeroes [8]byte
- _, err := w.Write(zeroes[:8-pad])
- return err
-}
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// nardump is like nix-store --dump, but in Go, writing a NAR
+// file (tar-like, but focused on being reproducible) to stdout
+// or to a hash with the --sri flag.
+//
+// It lets us calculate a Nix sha256 without the person running
+// git-pull-oss.sh having Nix available.
+package main
+
+// For the format, see:
+// See https://gist.github.com/jbeda/5c79d2b1434f0018d693
+
+import (
+ "bufio"
+ "crypto/sha256"
+ "encoding/base64"
+ "encoding/binary"
+ "flag"
+ "fmt"
+ "io"
+ "io/fs"
+ "log"
+ "os"
+ "path"
+ "sort"
+)
+
+var sri = flag.Bool("sri", false, "print SRI")
+
+func main() {
+ flag.Parse()
+ if flag.NArg() != 1 {
+ log.Fatal("usage: nardump <dir>")
+ }
+ arg := flag.Arg(0)
+ if err := os.Chdir(arg); err != nil {
+ log.Fatal(err)
+ }
+ if *sri {
+ hash := sha256.New()
+ if err := writeNAR(hash, os.DirFS(".")); err != nil {
+ log.Fatal(err)
+ }
+ fmt.Printf("sha256-%s\n", base64.StdEncoding.EncodeToString(hash.Sum(nil)))
+ return
+ }
+ bw := bufio.NewWriter(os.Stdout)
+ if err := writeNAR(bw, os.DirFS(".")); err != nil {
+ log.Fatal(err)
+ }
+ bw.Flush()
+}
+
+// writeNARError is a sentinel panic type that's recovered by writeNAR
+// and converted into the wrapped error.
+type writeNARError struct{ err error }
+
+// narWriter writes NAR files.
+type narWriter struct {
+ w io.Writer
+ fs fs.FS
+}
+
+// writeNAR writes a NAR file to w from the root of fs.
+func writeNAR(w io.Writer, fs fs.FS) (err error) {
+ defer func() {
+ if e := recover(); e != nil {
+ if we, ok := e.(writeNARError); ok {
+ err = we.err
+ return
+ }
+ panic(e)
+ }
+ }()
+ nw := &narWriter{w: w, fs: fs}
+ nw.str("nix-archive-1")
+ return nw.writeDir(".")
+}
+
+func (nw *narWriter) writeDir(dirPath string) error {
+ ents, err := fs.ReadDir(nw.fs, dirPath)
+ if err != nil {
+ return err
+ }
+ sort.Slice(ents, func(i, j int) bool {
+ return ents[i].Name() < ents[j].Name()
+ })
+ nw.str("(")
+ nw.str("type")
+ nw.str("directory")
+ for _, ent := range ents {
+ nw.str("entry")
+ nw.str("(")
+ nw.str("name")
+ nw.str(ent.Name())
+ nw.str("node")
+ mode := ent.Type()
+ sub := path.Join(dirPath, ent.Name())
+ var err error
+ switch {
+ case mode.IsRegular():
+ err = nw.writeRegular(sub)
+ case mode.IsDir():
+ err = nw.writeDir(sub)
+ default:
+ // TODO(bradfitz): symlink, but requires fighting io/fs a bit
+ // to get at Readlink or the osFS via fs. But for now
+ // we don't need symlinks because they're not in Go's archive.
+ return fmt.Errorf("unsupported file type %v at %q", sub, mode)
+ }
+ if err != nil {
+ return err
+ }
+ nw.str(")")
+ }
+ nw.str(")")
+ return nil
+}
+
+func (nw *narWriter) writeRegular(path string) error {
+ nw.str("(")
+ nw.str("type")
+ nw.str("regular")
+ fi, err := fs.Stat(nw.fs, path)
+ if err != nil {
+ return err
+ }
+ if fi.Mode()&0111 != 0 {
+ nw.str("executable")
+ nw.str("")
+ }
+ contents, err := fs.ReadFile(nw.fs, path)
+ if err != nil {
+ return err
+ }
+ nw.str("contents")
+ if err := writeBytes(nw.w, contents); err != nil {
+ return err
+ }
+ nw.str(")")
+ return nil
+}
+
+func (nw *narWriter) str(s string) {
+ if err := writeString(nw.w, s); err != nil {
+ panic(writeNARError{err})
+ }
+}
+
+func writeString(w io.Writer, s string) error {
+ var buf [8]byte
+ binary.LittleEndian.PutUint64(buf[:], uint64(len(s)))
+ if _, err := w.Write(buf[:]); err != nil {
+ return err
+ }
+ if _, err := io.WriteString(w, s); err != nil {
+ return err
+ }
+ return writePad(w, len(s))
+}
+
+func writeBytes(w io.Writer, b []byte) error {
+ var buf [8]byte
+ binary.LittleEndian.PutUint64(buf[:], uint64(len(b)))
+ if _, err := w.Write(buf[:]); err != nil {
+ return err
+ }
+ if _, err := w.Write(b); err != nil {
+ return err
+ }
+ return writePad(w, len(b))
+}
+
+func writePad(w io.Writer, n int) error {
+ pad := n % 8
+ if pad == 0 {
+ return nil
+ }
+ var zeroes [8]byte
+ _, err := w.Write(zeroes[:8-pad])
+ return err
+}
Copyright © 2025 - 2026 Wayne Cole. WTFPL. Attribution appreciated. No warranty. Not liable for bodily damages.