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- // Copyright 2019 The go-ethereum Authors
- // This file is part of the go-ethereum library.
- //
- // The go-ethereum library is free software: you can redistribute it and/or modify
- // it under the terms of the GNU Lesser General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // The go-ethereum library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU Lesser General Public License for more details.
- //
- // You should have received a copy of the GNU Lesser General Public License
- // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
- package build
- import (
- "bytes"
- "crypto/sha256"
- "fmt"
- "io/ioutil"
- "net/http"
- "os"
- "path/filepath"
- "strings"
- )
- // EnsureGoSources ensures that path contains a file with the given SHA256 hash,
- // and if not, it downloads a fresh Go source package from upstream and replaces
- // path with it (if the hash matches).
- func EnsureGoSources(version string, hash []byte, path string) error {
- // Sanity check the destination path to ensure we don't do weird things
- if !strings.HasSuffix(path, ".tar.gz") {
- return fmt.Errorf("destination path (%s) must end with .tar.gz", path)
- }
- // If the file exists, validate it's hash
- if archive, err := ioutil.ReadFile(path); err == nil { // Go sources are ~20MB, it's fine to read all
- hasher := sha256.New()
- hasher.Write(archive)
- have := hasher.Sum(nil)
- if bytes.Equal(have, hash) {
- fmt.Printf("Go %s [%x] available at %s\n", version, hash, path)
- return nil
- }
- fmt.Printf("Go %s hash mismatch (have %x, want %x) at %s, deleting old archive\n", version, have, hash, path)
- if err := os.Remove(path); err != nil {
- return err
- }
- }
- // Archive missing or bad hash, download a new one
- fmt.Printf("Downloading Go %s [want %x] into %s\n", version, hash, path)
- res, err := http.Get(fmt.Sprintf("https://dl.google.com/go/go%s.src.tar.gz", version))
- if err != nil || res.StatusCode != http.StatusOK {
- return fmt.Errorf("failed to access Go sources: code %d, err %v", res.StatusCode, err)
- }
- defer res.Body.Close()
- archive, err := ioutil.ReadAll(res.Body)
- if err != nil {
- return err
- }
- // Sanity check the downloaded archive, save if checks out
- hasher := sha256.New()
- hasher.Write(archive)
- if have := hasher.Sum(nil); !bytes.Equal(have, hash) {
- return fmt.Errorf("downloaded Go %s hash mismatch (have %x, want %x)", version, have, hash)
- }
- if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
- return err
- }
- if err := ioutil.WriteFile(path, archive, 0644); err != nil {
- return err
- }
- fmt.Printf("Downloaded Go %s [%x] into %s\n", version, hash, path)
- return nil
- }
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