all: make vendored copy of reexec (#28382)

a little copying is better than a little dependency

-- go proverb

We have this dependency on docker, a.k.a moby: a gigantic library, and we only need ~70 LOC,
so here I tried moving it inline instead.

Co-authored-by: Felix Lange <fjl@twurst.com>

build/update-license.go

@@ -65,10 +65,8 @@ var (
 		"vendor/", "tests/testdata/", "build/",
 
 		// don't relicense vendored sources
-		"cmd/internal/browser",
 		"common/bitutil/bitutil",
 		"common/prque/",
-		"consensus/ethash/xor.go",
 		"crypto/blake2b/",
 		"crypto/bn256/",
 		"crypto/bls12381/",
@@ -78,6 +76,7 @@ var (
 		"log/",
 		"metrics/",
 		"signer/rules/deps",
+		"internal/reexec",
 
 		// skip special licenses
 		"crypto/secp256k1", // Relicensed to BSD-3 via https://github.com/ethereum/go-ethereum/pull/17225

cmd/clef/run_test.go

@@ -21,8 +21,8 @@ import (
 	"os"
 	"testing"
 
-	"github.com/docker/docker/pkg/reexec"
 	"github.com/ethereum/go-ethereum/internal/cmdtest"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 )
 
 const registeredName = "clef-test"

cmd/ethkey/run_test.go

@@ -21,8 +21,8 @@ import (
 	"os"
 	"testing"
 
-	"github.com/docker/docker/pkg/reexec"
 	"github.com/ethereum/go-ethereum/internal/cmdtest"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 )
 
 type testEthkey struct {

cmd/evm/t8n_test.go

@@ -24,9 +24,9 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/docker/docker/pkg/reexec"
 	"github.com/ethereum/go-ethereum/cmd/evm/internal/t8ntool"
 	"github.com/ethereum/go-ethereum/internal/cmdtest"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 )
 
 func TestMain(m *testing.M) {

cmd/geth/logging_test.go

@@ -29,7 +29,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/docker/docker/pkg/reexec"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 )
 
 func runSelf(args ...string) ([]byte, error) {

cmd/geth/run_test.go

@@ -23,8 +23,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/docker/docker/pkg/reexec"
 	"github.com/ethereum/go-ethereum/internal/cmdtest"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 	"github.com/ethereum/go-ethereum/rpc"
 )
 

go.mod

@@ -19,7 +19,6 @@ require (
 	github.com/crate-crypto/go-kzg-4844 v0.7.0
 	github.com/davecgh/go-spew v1.1.1
 	github.com/deckarep/golang-set/v2 v2.1.0
-	github.com/docker/docker v24.0.5+incompatible
 	github.com/dop251/goja v0.0.0-20230806174421-c933cf95e127
 	github.com/ethereum/c-kzg-4844 v0.4.0
 	github.com/fatih/color v1.13.0
@@ -141,6 +140,5 @@ require (
 	golang.org/x/net v0.17.0 // indirect
 	google.golang.org/protobuf v1.27.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
-	gotest.tools/v3 v3.5.1 // indirect
 	rsc.io/tmplfunc v0.0.3 // indirect
 )

go.sum

@@ -169,8 +169,6 @@ github.com/dlclark/regexp2 v1.4.1-0.20201116162257-a2a8dda75c91/go.mod h1:2pZnwu
 github.com/dlclark/regexp2 v1.7.0 h1:7lJfhqlPssTb1WQx4yvTHN0uElPEv52sbaECrAQxjAo=
 github.com/dlclark/regexp2 v1.7.0/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
 github.com/dnaeon/go-vcr v1.2.0 h1:zHCHvJYTMh1N7xnV7zf1m1GPBF9Ad0Jk/whtQ1663qI=
-github.com/docker/docker v24.0.5+incompatible h1:WmgcE4fxyI6EEXxBRxsHnZXrO1pQ3smi0k/jho4HLeY=
-github.com/docker/docker v24.0.5+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
 github.com/dop251/goja v0.0.0-20211022113120-dc8c55024d06/go.mod h1:R9ET47fwRVRPZnOGvHxxhuZcbrMCuiqOz3Rlrh4KSnk=
 github.com/dop251/goja v0.0.0-20230806174421-c933cf95e127 h1:qwcF+vdFrvPSEUDSX5RVoRccG8a5DhOdWdQ4zN62zzo=
 github.com/dop251/goja v0.0.0-20230806174421-c933cf95e127/go.mod h1:QMWlm50DNe14hD7t24KEqZuUdC9sOTy8W6XbCU1mlw4=
@@ -963,8 +961,6 @@ gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gotest.tools/v3 v3.5.1 h1:EENdUnS3pdur5nybKYIh2Vfgc8IUNBjxDPSjtiJcOzU=
-gotest.tools/v3 v3.5.1/go.mod h1:isy3WKz7GK6uNw/sbHzfKBLvlvXwUyV06n6brMxxopU=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

internal/cmdtest/test_cmd.go

@@ -32,7 +32,7 @@ import (
 	"text/template"
 	"time"
 
-	"github.com/docker/docker/pkg/reexec"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 )
 
 func NewTestCmd(t *testing.T, data interface{}) *TestCmd {

internal/reexec/reexec.go

@@ -0,0 +1,35 @@
+// This file originates from Docker/Moby,
+// https://github.com/moby/moby/blob/master/pkg/reexec/reexec.go
+// Licensed under Apache License 2.0: https://github.com/moby/moby/blob/master/LICENSE
+// Copyright 2013-2018 Docker, Inc.
+//
+// Package reexec facilitates the busybox style reexec of the docker binary that
+// we require because of the forking limitations of using Go.  Handlers can be
+// registered with a name and the argv 0 of the exec of the binary will be used
+// to find and execute custom init paths.
+package reexec
+
+import (
+	"fmt"
+	"os"
+)
+
+var registeredInitializers = make(map[string]func())
+
+// Register adds an initialization func under the specified name
+func Register(name string, initializer func()) {
+	if _, exists := registeredInitializers[name]; exists {
+		panic(fmt.Sprintf("reexec func already registered under name %q", name))
+	}
+	registeredInitializers[name] = initializer
+}
+
+// Init is called as the first part of the exec process and returns true if an
+// initialization function was called.
+func Init() bool {
+	if initializer, ok := registeredInitializers[os.Args[0]]; ok {
+		initializer()
+		return true
+	}
+	return false
+}

internal/reexec/self_linux.go

@@ -0,0 +1,14 @@
+// This file originates from Docker/Moby,
+// https://github.com/moby/moby/blob/master/pkg/reexec/
+// Licensed under Apache License 2.0: https://github.com/moby/moby/blob/master/LICENSE
+// Copyright 2013-2018 Docker, Inc.
+
+//go:build linux
+
+package reexec
+
+// Self returns the path to the current process's binary.
+// Returns "/proc/self/exe".
+func Self() string {
+	return "/proc/self/exe"
+}

internal/reexec/self_others.go

@@ -0,0 +1,32 @@
+// This file originates from Docker/Moby,
+// https://github.com/moby/moby/blob/master/pkg/reexec/
+// Licensed under Apache License 2.0: https://github.com/moby/moby/blob/master/LICENSE
+// Copyright 2013-2018 Docker, Inc.
+
+//go:build !linux
+
+package reexec
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+)
+
+// Self returns the path to the current process's binary.
+// Uses os.Args[0].
+func Self() string {
+	name := os.Args[0]
+	if filepath.Base(name) == name {
+		if lp, err := exec.LookPath(name); err == nil {
+			return lp
+		}
+	}
+	// handle conversion of relative paths to absolute
+	if absName, err := filepath.Abs(name); err == nil {
+		return absName
+	}
+	// if we couldn't get absolute name, return original
+	// (NOTE: Go only errors on Abs() if os.Getwd fails)
+	return name
+}

p2p/simulations/adapters/exec.go

@@ -34,7 +34,7 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/docker/docker/pkg/reexec"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/p2p"

p2p/simulations/adapters/types.go

@@ -25,8 +25,8 @@ import (
 	"os"
 	"strconv"
 
-	"github.com/docker/docker/pkg/reexec"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/internal/reexec"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/p2p"