merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

7 files changed, 872 insertions, 0 deletions

diff --git a/third_party/git/contrib/persistent-https/LICENSE b/third_party/git/contrib/persistent-https/LICENSE
new file mode 100644
index 000000000000..d64569567334
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/LICENSE
@@ -0,0 +1,202 @@
+
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+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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diff --git a/third_party/git/contrib/persistent-https/Makefile b/third_party/git/contrib/persistent-https/Makefile
new file mode 100644
index 000000000000..52b84ba3d439
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/Makefile
@@ -0,0 +1,40 @@
+# Copyright 2012 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+BUILD_LABEL=$(shell cut -d" " -f3 ../../GIT-VERSION-FILE)
+TAR_OUT=$(shell go env GOOS)_$(shell go env GOARCH).tar.gz
+
+all: git-remote-persistent-https git-remote-persistent-https--proxy \
+	git-remote-persistent-http
+
+git-remote-persistent-https--proxy: git-remote-persistent-https
+	ln -f -s git-remote-persistent-https git-remote-persistent-https--proxy
+
+git-remote-persistent-http: git-remote-persistent-https
+	ln -f -s git-remote-persistent-https git-remote-persistent-http
+
+git-remote-persistent-https:
+	case $$(go version) in \
+	"go version go"1.[0-5].*) EQ=" " ;; *) EQ="=" ;; esac && \
+	go build -o git-remote-persistent-https \
+		-ldflags "-X main._BUILD_EMBED_LABEL$${EQ}$(BUILD_LABEL)"
+
+clean:
+	rm -f git-remote-persistent-http* *.tar.gz
+
+tar: clean all
+	@chmod 555 git-remote-persistent-https
+	@tar -czf $(TAR_OUT) git-remote-persistent-http* README LICENSE
+	@echo
+	@echo "Created $(TAR_OUT)"
diff --git a/third_party/git/contrib/persistent-https/README b/third_party/git/contrib/persistent-https/README
new file mode 100644
index 000000000000..7c4cd8d257da
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/README
@@ -0,0 +1,72 @@
+git-remote-persistent-https
+
+The git-remote-persistent-https binary speeds up SSL operations
+by running a daemon job (git-remote-persistent-https--proxy) that
+keeps a connection open to a server.
+
+
+PRE-BUILT BINARIES
+
+Darwin amd64:
+https://commondatastorage.googleapis.com/git-remote-persistent-https/darwin_amd64.tar.gz
+
+Linux amd64:
+https://commondatastorage.googleapis.com/git-remote-persistent-https/linux_amd64.tar.gz
+
+
+INSTALLING
+
+Move all of the git-remote-persistent-http* binaries to a directory
+in PATH.
+
+
+USAGE
+
+HTTPS requests can be delegated to the proxy by using the
+"persistent-https" scheme, e.g.
+
+git clone persistent-https://kernel.googlesource.com/pub/scm/git/git
+
+Likewise, .gitconfig can be updated as follows to rewrite https urls
+to use persistent-https:
+
+[url "persistent-https"]
+	insteadof = https
+[url "persistent-http"]
+	insteadof = http
+
+You may also want to allow the use of the persistent-https helper for
+submodule URLs (since any https URLs pointing to submodules will be
+rewritten, and Git's out-of-the-box defaults forbid submodules from
+using unknown remote helpers):
+
+[protocol "persistent-https"]
+	allow = always
+[protocol "persistent-http"]
+	allow = always
+
+
+#####################################################################
+# BUILDING FROM SOURCE
+#####################################################################
+
+LOCATION
+
+The source is available in the contrib/persistent-https directory of
+the Git source repository. The Git source repository is available at
+git://git.kernel.org/pub/scm/git/git.git/
+https://kernel.googlesource.com/pub/scm/git/git
+
+
+PREREQUISITES
+
+The code is written in Go (http://golang.org/) and the Go compiler is
+required. Currently, the compiler must be built and installed from tip
+of source, in order to include a fix in the reverse http proxy:
+http://code.google.com/p/go/source/detail?r=a615b796570a2cd8591884767a7d67ede74f6648
+
+
+BUILDING
+
+Run "make" to build the binaries. See the section on
+INSTALLING above.
diff --git a/third_party/git/contrib/persistent-https/client.go b/third_party/git/contrib/persistent-https/client.go
new file mode 100644
index 000000000000..71125b5832d3
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/client.go
@@ -0,0 +1,189 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"net"
+	"net/url"
+	"os"
+	"os/exec"
+	"strings"
+	"syscall"
+	"time"
+)
+
+type Client struct {
+	ProxyBin string
+	Args     []string
+
+	insecure bool
+}
+
+func (c *Client) Run() error {
+	if err := c.resolveArgs(); err != nil {
+		return fmt.Errorf("resolveArgs() got error: %v", err)
+	}
+
+	// Connect to the proxy.
+	uconn, hconn, addr, err := c.connect()
+	if err != nil {
+		return fmt.Errorf("connect() got error: %v", err)
+	}
+	// Keep the unix socket connection open for the duration of the request.
+	defer uconn.Close()
+	// Keep a connection to the HTTP server open, so no other user can
+	// bind on the same address so long as the process is running.
+	defer hconn.Close()
+
+	// Start the git-remote-http subprocess.
+	cargs := []string{"-c", fmt.Sprintf("http.proxy=%v", addr), "remote-http"}
+	cargs = append(cargs, c.Args...)
+	cmd := exec.Command("git", cargs...)
+
+	for _, v := range os.Environ() {
+		if !strings.HasPrefix(v, "GIT_PERSISTENT_HTTPS_SECURE=") {
+			cmd.Env = append(cmd.Env, v)
+		}
+	}
+	// Set the GIT_PERSISTENT_HTTPS_SECURE environment variable when
+	// the proxy is using a SSL connection.  This allows credential helpers
+	// to identify secure proxy connections, despite being passed an HTTP
+	// scheme.
+	if !c.insecure {
+		cmd.Env = append(cmd.Env, "GIT_PERSISTENT_HTTPS_SECURE=1")
+	}
+
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		if eerr, ok := err.(*exec.ExitError); ok {
+			if stat, ok := eerr.ProcessState.Sys().(syscall.WaitStatus); ok && stat.ExitStatus() != 0 {
+				os.Exit(stat.ExitStatus())
+			}
+		}
+		return fmt.Errorf("git-remote-http subprocess got error: %v", err)
+	}
+	return nil
+}
+
+func (c *Client) connect() (uconn net.Conn, hconn net.Conn, addr string, err error) {
+	uconn, err = DefaultSocket.Dial()
+	if err != nil {
+		if e, ok := err.(*net.OpError); ok && (os.IsNotExist(e.Err) || e.Err == syscall.ECONNREFUSED) {
+			if err = c.startProxy(); err == nil {
+				uconn, err = DefaultSocket.Dial()
+			}
+		}
+		if err != nil {
+			return
+		}
+	}
+
+	if addr, err = c.readAddr(uconn); err != nil {
+		return
+	}
+
+	// Open a tcp connection to the proxy.
+	if hconn, err = net.Dial("tcp", addr); err != nil {
+		return
+	}
+
+	// Verify the address hasn't changed ownership.
+	var addr2 string
+	if addr2, err = c.readAddr(uconn); err != nil {
+		return
+	} else if addr != addr2 {
+		err = fmt.Errorf("address changed after connect. got %q, want %q", addr2, addr)
+		return
+	}
+	return
+}
+
+func (c *Client) readAddr(conn net.Conn) (string, error) {
+	conn.SetDeadline(time.Now().Add(5 * time.Second))
+	data := make([]byte, 100)
+	n, err := conn.Read(data)
+	if err != nil {
+		return "", fmt.Errorf("error reading unix socket: %v", err)
+	} else if n == 0 {
+		return "", errors.New("empty data response")
+	}
+	conn.Write([]byte{1}) // Ack
+
+	var addr string
+	if addrs := strings.Split(string(data[:n]), "\n"); len(addrs) != 2 {
+		return "", fmt.Errorf("got %q, wanted 2 addresses", data[:n])
+	} else if c.insecure {
+		addr = addrs[1]
+	} else {
+		addr = addrs[0]
+	}
+	return addr, nil
+}
+
+func (c *Client) startProxy() error {
+	cmd := exec.Command(c.ProxyBin)
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	defer stdout.Close()
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	result := make(chan error)
+	go func() {
+		bytes, _, err := bufio.NewReader(stdout).ReadLine()
+		if line := string(bytes); err == nil && line != "OK" {
+			err = fmt.Errorf("proxy returned %q, want \"OK\"", line)
+		}
+		result <- err
+	}()
+	select {
+	case err := <-result:
+		return err
+	case <-time.After(5 * time.Second):
+		return errors.New("timeout waiting for proxy to start")
+	}
+	panic("not reachable")
+}
+
+func (c *Client) resolveArgs() error {
+	if nargs := len(c.Args); nargs == 0 {
+		return errors.New("remote needed")
+	} else if nargs > 2 {
+		return fmt.Errorf("want at most 2 args, got %v", c.Args)
+	}
+
+	// Rewrite the url scheme to be http.
+	idx := len(c.Args) - 1
+	rawurl := c.Args[idx]
+	rurl, err := url.Parse(rawurl)
+	if err != nil {
+		return fmt.Errorf("invalid remote: %v", err)
+	}
+	c.insecure = rurl.Scheme == "persistent-http"
+	rurl.Scheme = "http"
+	c.Args[idx] = rurl.String()
+	if idx != 0 && c.Args[0] == rawurl {
+		c.Args[0] = c.Args[idx]
+	}
+	return nil
+}
diff --git a/third_party/git/contrib/persistent-https/main.go b/third_party/git/contrib/persistent-https/main.go
new file mode 100644
index 000000000000..fd1b1077439b
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/main.go
@@ -0,0 +1,82 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// The git-remote-persistent-https binary speeds up SSL operations by running
+// a daemon job that keeps a connection open to a Git server. This ensures the
+// git-remote-persistent-https--proxy is running and delegating execution
+// to the git-remote-http binary with the http_proxy set to the daemon job.
+// A unix socket is used to authenticate the proxy and discover the
+// HTTP address. Note, both the client and proxy are included in the same
+// binary.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+	"time"
+)
+
+var (
+	forceProxy = flag.Bool("proxy", false, "Whether to start the binary in proxy mode")
+	proxyBin   = flag.String("proxy_bin", "git-remote-persistent-https--proxy", "Path to the proxy binary")
+	printLabel = flag.Bool("print_label", false, "Prints the build label for the binary")
+
+	// Variable that should be defined through the -X linker flag.
+	_BUILD_EMBED_LABEL string
+)
+
+const (
+	defaultMaxIdleDuration    = 24 * time.Hour
+	defaultPollUpdateInterval = 15 * time.Minute
+)
+
+func main() {
+	flag.Parse()
+	if *printLabel {
+		// Short circuit execution to print the build label
+		fmt.Println(buildLabel())
+		return
+	}
+
+	var err error
+	if *forceProxy || strings.HasSuffix(os.Args[0], "--proxy") {
+		log.SetPrefix("git-remote-persistent-https--proxy: ")
+		proxy := &Proxy{
+			BuildLabel:         buildLabel(),
+			MaxIdleDuration:    defaultMaxIdleDuration,
+			PollUpdateInterval: defaultPollUpdateInterval,
+		}
+		err = proxy.Run()
+	} else {
+		log.SetPrefix("git-remote-persistent-https: ")
+		client := &Client{
+			ProxyBin: *proxyBin,
+			Args:     flag.Args(),
+		}
+		err = client.Run()
+	}
+	if err != nil {
+		log.Fatalln(err)
+	}
+}
+
+func buildLabel() string {
+	if _BUILD_EMBED_LABEL == "" {
+		log.Println(`unlabeled build; build with "make" to label`)
+	}
+	return _BUILD_EMBED_LABEL
+}
diff --git a/third_party/git/contrib/persistent-https/proxy.go b/third_party/git/contrib/persistent-https/proxy.go
new file mode 100644
index 000000000000..bb0cdba3864c
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/proxy.go
@@ -0,0 +1,190 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"os"
+	"os/exec"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+)
+
+type Proxy struct {
+	BuildLabel         string
+	MaxIdleDuration    time.Duration
+	PollUpdateInterval time.Duration
+
+	ul        net.Listener
+	httpAddr  string
+	httpsAddr string
+}
+
+func (p *Proxy) Run() error {
+	hl, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		return fmt.Errorf("http listen failed: %v", err)
+	}
+	defer hl.Close()
+
+	hsl, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		return fmt.Errorf("https listen failed: %v", err)
+	}
+	defer hsl.Close()
+
+	p.ul, err = DefaultSocket.Listen()
+	if err != nil {
+		c, derr := DefaultSocket.Dial()
+		if derr == nil {
+			c.Close()
+			fmt.Println("OK\nA proxy is already running... exiting")
+			return nil
+		} else if e, ok := derr.(*net.OpError); ok && e.Err == syscall.ECONNREFUSED {
+			// Nothing is listening on the socket, unlink it and try again.
+			syscall.Unlink(DefaultSocket.Path())
+			p.ul, err = DefaultSocket.Listen()
+		}
+		if err != nil {
+			return fmt.Errorf("unix listen failed on %v: %v", DefaultSocket.Path(), err)
+		}
+	}
+	defer p.ul.Close()
+	go p.closeOnSignal()
+	go p.closeOnUpdate()
+
+	p.httpAddr = hl.Addr().String()
+	p.httpsAddr = hsl.Addr().String()
+	fmt.Printf("OK\nListening on unix socket=%v http=%v https=%v\n",
+		p.ul.Addr(), p.httpAddr, p.httpsAddr)
+
+	result := make(chan error, 2)
+	go p.serveUnix(result)
+	go func() {
+		result <- http.Serve(hl, &httputil.ReverseProxy{
+			FlushInterval: 500 * time.Millisecond,
+			Director:      func(r *http.Request) {},
+		})
+	}()
+	go func() {
+		result <- http.Serve(hsl, &httputil.ReverseProxy{
+			FlushInterval: 500 * time.Millisecond,
+			Director: func(r *http.Request) {
+				r.URL.Scheme = "https"
+			},
+		})
+	}()
+	return <-result
+}
+
+type socketContext struct {
+	sync.WaitGroup
+	mutex sync.Mutex
+	last  time.Time
+}
+
+func (sc *socketContext) Done() {
+	sc.mutex.Lock()
+	defer sc.mutex.Unlock()
+	sc.last = time.Now()
+	sc.WaitGroup.Done()
+}
+
+func (p *Proxy) serveUnix(result chan<- error) {
+	sockCtx := &socketContext{}
+	go p.closeOnIdle(sockCtx)
+
+	var err error
+	for {
+		var uconn net.Conn
+		uconn, err = p.ul.Accept()
+		if err != nil {
+			err = fmt.Errorf("accept failed: %v", err)
+			break
+		}
+		sockCtx.Add(1)
+		go p.handleUnixConn(sockCtx, uconn)
+	}
+	sockCtx.Wait()
+	result <- err
+}
+
+func (p *Proxy) handleUnixConn(sockCtx *socketContext, uconn net.Conn) {
+	defer sockCtx.Done()
+	defer uconn.Close()
+	data := []byte(fmt.Sprintf("%v\n%v", p.httpsAddr, p.httpAddr))
+	uconn.SetDeadline(time.Now().Add(5 * time.Second))
+	for i := 0; i < 2; i++ {
+		if n, err := uconn.Write(data); err != nil {
+			log.Printf("error sending http addresses: %+v\n", err)
+			return
+		} else if n != len(data) {
+			log.Printf("sent %d data bytes, wanted %d\n", n, len(data))
+			return
+		}
+		if _, err := uconn.Read([]byte{0, 0, 0, 0}); err != nil {
+			log.Printf("error waiting for Ack: %+v\n", err)
+			return
+		}
+	}
+	// Wait without a deadline for the client to finish via EOF
+	uconn.SetDeadline(time.Time{})
+	uconn.Read([]byte{0, 0, 0, 0})
+}
+
+func (p *Proxy) closeOnIdle(sockCtx *socketContext) {
+	for d := p.MaxIdleDuration; d > 0; {
+		time.Sleep(d)
+		sockCtx.Wait()
+		sockCtx.mutex.Lock()
+		if d = sockCtx.last.Add(p.MaxIdleDuration).Sub(time.Now()); d <= 0 {
+			log.Println("graceful shutdown from idle timeout")
+			p.ul.Close()
+		}
+		sockCtx.mutex.Unlock()
+	}
+}
+
+func (p *Proxy) closeOnUpdate() {
+	for {
+		time.Sleep(p.PollUpdateInterval)
+		if out, err := exec.Command(os.Args[0], "--print_label").Output(); err != nil {
+			log.Printf("error polling for updated binary: %v\n", err)
+		} else if s := string(out[:len(out)-1]); p.BuildLabel != s {
+			log.Printf("graceful shutdown from updated binary: %q --> %q\n", p.BuildLabel, s)
+			p.ul.Close()
+			break
+		}
+	}
+}
+
+func (p *Proxy) closeOnSignal() {
+	ch := make(chan os.Signal, 10)
+	signal.Notify(ch, os.Interrupt, os.Kill, os.Signal(syscall.SIGTERM), os.Signal(syscall.SIGHUP))
+	sig := <-ch
+	p.ul.Close()
+	switch sig {
+	case os.Signal(syscall.SIGHUP):
+		log.Printf("graceful shutdown from signal: %v\n", sig)
+	default:
+		log.Fatalf("exiting from signal: %v\n", sig)
+	}
+}
diff --git a/third_party/git/contrib/persistent-https/socket.go b/third_party/git/contrib/persistent-https/socket.go
new file mode 100644
index 000000000000..193b911dd13a
--- /dev/null
+++ b/third_party/git/contrib/persistent-https/socket.go
@@ -0,0 +1,97 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// A Socket is a wrapper around a Unix socket that verifies directory
+// permissions.
+type Socket struct {
+	Dir string
+}
+
+func defaultDir() string {
+	sockPath := ".git-credential-cache"
+	if home := os.Getenv("HOME"); home != "" {
+		return filepath.Join(home, sockPath)
+	}
+	log.Printf("socket: cannot find HOME path. using relative directory %q for socket", sockPath)
+	return sockPath
+}
+
+// DefaultSocket is a Socket in the $HOME/.git-credential-cache directory.
+var DefaultSocket = Socket{Dir: defaultDir()}
+
+// Listen announces the local network address of the unix socket. The
+// permissions on the socket directory are verified before attempting
+// the actual listen.
+func (s Socket) Listen() (net.Listener, error) {
+	network, addr := "unix", s.Path()
+	if err := s.mkdir(); err != nil {
+		return nil, &net.OpError{Op: "listen", Net: network, Addr: &net.UnixAddr{Name: addr, Net: network}, Err: err}
+	}
+	return net.Listen(network, addr)
+}
+
+// Dial connects to the unix socket. The permissions on the socket directory
+// are verified before attempting the actual dial.
+func (s Socket) Dial() (net.Conn, error) {
+	network, addr := "unix", s.Path()
+	if err := s.checkPermissions(); err != nil {
+		return nil, &net.OpError{Op: "dial", Net: network, Addr: &net.UnixAddr{Name: addr, Net: network}, Err: err}
+	}
+	return net.Dial(network, addr)
+}
+
+// Path returns the fully specified file name of the unix socket.
+func (s Socket) Path() string {
+	return filepath.Join(s.Dir, "persistent-https-proxy-socket")
+}
+
+func (s Socket) mkdir() error {
+	if err := s.checkPermissions(); err == nil {
+		return nil
+	} else if !os.IsNotExist(err) {
+		return err
+	}
+	if err := os.MkdirAll(s.Dir, 0700); err != nil {
+		return err
+	}
+	return s.checkPermissions()
+}
+
+func (s Socket) checkPermissions() error {
+	fi, err := os.Stat(s.Dir)
+	if err != nil {
+		return err
+	}
+	if !fi.IsDir() {
+		return fmt.Errorf("socket: got file, want directory for %q", s.Dir)
+	}
+	if fi.Mode().Perm() != 0700 {
+		return fmt.Errorf("socket: got perm %o, want 700 for %q", fi.Mode().Perm(), s.Dir)
+	}
+	if st := fi.Sys().(*syscall.Stat_t); int(st.Uid) != os.Getuid() {
+		return fmt.Errorf("socket: got uid %d, want %d for %q", st.Uid, os.Getuid(), s.Dir)
+	}
+	return nil
+}