Fix panic when parsing resolv.conf

vendor/golang.org/x/net/trace/events.go

@@ -39,9 +39,9 @@ var buckets = []bucket{
 }
 
 // RenderEvents renders the HTML page typically served at /debug/events.
-// It does not do any auth checking; see AuthRequest for the default auth check
-// used by the handler registered on http.DefaultServeMux.
-// req may be nil.
+// It does not do any auth checking. The request may be nil.
+//
+// Most users will use the Events handler.
 func RenderEvents(w http.ResponseWriter, req *http.Request, sensitive bool) {
 	now := time.Now()
 	data := &struct {

vendor/golang.org/x/net/trace/trace.go

@@ -64,7 +64,6 @@ package trace // import "golang.org/x/net/trace"
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"html/template"
 	"io"
@@ -111,30 +110,46 @@ var AuthRequest = func(req *http.Request) (any, sensitive bool) {
 }
 
 func init() {
-	http.HandleFunc("/debug/requests", func(w http.ResponseWriter, req *http.Request) {
-		any, sensitive := AuthRequest(req)
-		if !any {
-			http.Error(w, "not allowed", http.StatusUnauthorized)
-			return
-		}
-		w.Header().Set("Content-Type", "text/html; charset=utf-8")
-		Render(w, req, sensitive)
-	})
-	http.HandleFunc("/debug/events", func(w http.ResponseWriter, req *http.Request) {
-		any, sensitive := AuthRequest(req)
-		if !any {
-			http.Error(w, "not allowed", http.StatusUnauthorized)
-			return
-		}
-		w.Header().Set("Content-Type", "text/html; charset=utf-8")
-		RenderEvents(w, req, sensitive)
-	})
+	// TODO(jbd): Serve Traces from /debug/traces in the future?
+	// There is no requirement for a request to be present to have traces.
+	http.HandleFunc("/debug/requests", Traces)
+	http.HandleFunc("/debug/events", Events)
+}
+
+// Traces responds with traces from the program.
+// The package initialization registers it in http.DefaultServeMux
+// at /debug/requests.
+//
+// It performs authorization by running AuthRequest.
+func Traces(w http.ResponseWriter, req *http.Request) {
+	any, sensitive := AuthRequest(req)
+	if !any {
+		http.Error(w, "not allowed", http.StatusUnauthorized)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	Render(w, req, sensitive)
+}
+
+// Events responds with a page of events collected by EventLogs.
+// The package initialization registers it in http.DefaultServeMux
+// at /debug/events.
+//
+// It performs authorization by running AuthRequest.
+func Events(w http.ResponseWriter, req *http.Request) {
+	any, sensitive := AuthRequest(req)
+	if !any {
+		http.Error(w, "not allowed", http.StatusUnauthorized)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	RenderEvents(w, req, sensitive)
 }
 
 // Render renders the HTML page typically served at /debug/requests.
-// It does not do any auth checking; see AuthRequest for the default auth check
-// used by the handler registered on http.DefaultServeMux.
-// req may be nil.
+// It does not do any auth checking. The request may be nil.
+//
+// Most users will use the Traces handler.
 func Render(w io.Writer, req *http.Request, sensitive bool) {
 	data := &struct {
 		Families         []string
@@ -271,18 +286,6 @@ type contextKeyT string
 
 var contextKey = contextKeyT("golang.org/x/net/trace.Trace")
 
-// NewContext returns a copy of the parent context
-// and associates it with a Trace.
-func NewContext(ctx context.Context, tr Trace) context.Context {
-	return context.WithValue(ctx, contextKey, tr)
-}
-
-// FromContext returns the Trace bound to the context, if any.
-func FromContext(ctx context.Context) (tr Trace, ok bool) {
-	tr, ok = ctx.Value(contextKey).(Trace)
-	return
-}
-
 // Trace represents an active request.
 type Trace interface {
 	// LazyLog adds x to the event log. It will be evaluated each time the

vendor/golang.org/x/net/trace/trace_go16.go

@@ -0,0 +1,21 @@
+// Copyright 2017 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.
+
+// +build !go1.7
+
+package trace
+
+import "golang.org/x/net/context"
+
+// NewContext returns a copy of the parent context
+// and associates it with a Trace.
+func NewContext(ctx context.Context, tr Trace) context.Context {
+	return context.WithValue(ctx, contextKey, tr)
+}
+
+// FromContext returns the Trace bound to the context, if any.
+func FromContext(ctx context.Context) (tr Trace, ok bool) {
+	tr, ok = ctx.Value(contextKey).(Trace)
+	return
+}

vendor/golang.org/x/net/trace/trace_go17.go

@@ -0,0 +1,21 @@
+// Copyright 2017 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.
+
+// +build go1.7
+
+package trace
+
+import "context"
+
+// NewContext returns a copy of the parent context
+// and associates it with a Trace.
+func NewContext(ctx context.Context, tr Trace) context.Context {
+	return context.WithValue(ctx, contextKey, tr)
+}
+
+// FromContext returns the Trace bound to the context, if any.
+func FromContext(ctx context.Context) (tr Trace, ok bool) {
+	tr, ok = ctx.Value(contextKey).(Trace)
+	return
+}