cmd/go: merge module support from x/vgo repo

This CL corresponds to CL 123361, the final manual CL in that repo,
making this the final manual sync.

All future commits will happen in this repo (the main Go repo),
and we'll update x/vgo automatically with a fixed patch+script.

Change-Id: I572243309c1809727604fd704705a23c30e85d1a
Reviewed-on: https://go-review.googlesource.com/123576
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
new file mode 100644
index 0000000000..27cd9ed5f8
--- /dev/null
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -0,0 +1,75 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modcmd
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/dirhash"
+	"cmd/go/internal/modfetch"
+	"cmd/go/internal/modload"
+	"cmd/go/internal/module"
+)
+
+func runVerify() {
+	ok := true
+	for _, mod := range modload.LoadBuildList()[1:] {
+		ok = verifyMod(mod) && ok
+	}
+	if ok {
+		fmt.Printf("all modules verified\n")
+	}
+}
+
+func verifyMod(mod module.Version) bool {
+	ok := true
+	zip := filepath.Join(modfetch.SrcMod, "cache/download", mod.Path, "/@v/", mod.Version+".zip")
+	_, zipErr := os.Stat(zip)
+	dir := filepath.Join(modfetch.SrcMod, mod.Path+"@"+mod.Version)
+	_, dirErr := os.Stat(dir)
+	data, err := ioutil.ReadFile(zip + "hash")
+	if err != nil {
+		if zipErr != nil && os.IsNotExist(zipErr) && dirErr != nil && os.IsNotExist(dirErr) {
+			// Nothing downloaded yet. Nothing to verify.
+			return true
+		}
+		base.Errorf("%s %s: missing ziphash: %v", mod.Path, mod.Version, err)
+		return false
+	}
+	h := string(bytes.TrimSpace(data))
+
+	if zipErr != nil && os.IsNotExist(zipErr) {
+		// ok
+	} else {
+		hZ, err := dirhash.HashZip(zip, dirhash.DefaultHash)
+		if err != nil {
+			base.Errorf("%s %s: %v", mod.Path, mod.Version, err)
+			return false
+		} else if hZ != h {
+			base.Errorf("%s %s: zip has been modified (%v)", mod.Path, mod.Version, zip)
+			ok = false
+		}
+	}
+	if dirErr != nil && os.IsNotExist(dirErr) {
+		// ok
+	} else {
+		hD, err := dirhash.HashDir(dir, mod.Path+"@"+mod.Version, dirhash.DefaultHash)
+		if err != nil {
+
+			base.Errorf("%s %s: %v", mod.Path, mod.Version, err)
+			return false
+		}
+		if hD != h {
+			base.Errorf("%s %s: dir has been modified (%v)", mod.Path, mod.Version, dir)
+			ok = false
+		}
+	}
+	return ok
+}