rebasing patches for go1.21

.github/workflows/build.yml

@@ -0,0 +1,108 @@
+name: Build toolchain
+
+permissions:
+  contents: write
+
+on:
+  push:
+    branches:
+      - tailscale
+      - 'tailscale.go1.21'
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  test:
+    runs-on: ubuntu-20.04
+    steps:
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: test
+      run: cd src && ./all.bash
+
+  build_release:
+    strategy:
+      matrix:
+        GOOS: ["linux", "darwin"]
+        GOARCH: ["amd64", "arm64"]
+    runs-on: ubuntu-20.04
+    if: github.event_name == 'push'
+    steps:
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: build
+      run: cd src && ./make.bash
+      env:
+        GOOS: "${{ matrix.GOOS }}"
+        GOARCH: "${{ matrix.GOARCH }}"
+        CGO_ENABLED: "0"
+    - name: trim unnecessary bits
+      run: |
+        rm -rf pkg/*_*
+        mv pkg/tool/${{ matrix.GOOS }}_${{ matrix.GOARCH }} pkg
+        rm -rf pkg/tool/*_*
+        mv -f bin/${{ matrix.GOOS }}_${{ matrix.GOARCH }}/* bin/ || true
+        rm -rf bin/${{ matrix.GOOS }}_${{ matrix.GOARCH }}
+        mv pkg/${{ matrix.GOOS }}_${{ matrix.GOARCH }} pkg/tool
+        find . -type d -name 'testdata' -print0 | xargs -0 rm -rf
+        find . -name '*_test.go' -delete
+    - name: archive
+      run: cd .. && tar --exclude-vcs -zcf ${{ matrix.GOOS }}-${{ matrix.GOARCH }}.tar.gz go
+    - name: save
+      uses: actions/upload-artifact@v1
+      with:
+        name: ${{ matrix.GOOS }}-${{ matrix.GOARCH }}
+        path: ../${{ matrix.GOOS }}-${{ matrix.GOARCH }}.tar.gz
+
+  create_release:
+    runs-on: ubuntu-20.04
+    if: github.event_name == 'push'
+    needs: [test, build_release]
+    outputs:
+      url: ${{ steps.create_release.outputs.upload_url }}
+    steps:
+    - name: create release
+      id: create_release
+      uses: actions/create-release@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        # Release name can't be the same as tag name, sigh
+        tag_name: build-${{ github.sha }}
+        release_name: ${{ github.sha }}
+        draft: false
+        prerelease: true
+
+  upload_release:
+    strategy:
+      matrix:
+        GOOS: ["linux", "darwin"]
+        GOARCH: ["amd64", "arm64"]
+    runs-on: ubuntu-20.04
+    if: github.event_name == 'push'
+    needs: [create_release]
+    steps:
+    - name: download artifact
+      uses: actions/download-artifact@v1
+      with:
+        name: ${{ matrix.GOOS }}-${{ matrix.GOARCH }}
+    - name: upload artifact
+      uses: actions/upload-release-asset@v1
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      with:
+        upload_url: ${{ needs.create_release.outputs.url }}
+        asset_path: ${{ matrix.GOOS }}-${{ matrix.GOARCH }}/${{ matrix.GOOS }}-${{ matrix.GOARCH }}.tar.gz
+        asset_name: ${{ matrix.GOOS }}-${{ matrix.GOARCH }}.tar.gz
+        asset_content_type: application/gzip
+
+  clean_old:
+    runs-on: ubuntu-20.04
+    if: github.event_name == 'push'
+    needs: [upload_release]
+    steps:
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: Delete older builds
+      run: ./.github/workflows/prune_old_builds.sh "${{ secrets.GITHUB_TOKEN }}"

.github/workflows/prune_old_builds.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+set -euo pipefail
+
+KEEP=10
+GITHUB_TOKEN=$1
+
+delete_release() {
+    release_id=$1
+    tag_name=$2
+    set -x
+    curl -X DELETE --header "Authorization: Bearer $GITHUB_TOKEN" "https://api.github.com/repos/tailscale/go/releases/$release_id"
+    curl -X DELETE --header "Authorization: Bearer $GITHUB_TOKEN" "https://api.github.com/repos/tailscale/go/git/refs/tags/$tag_name"
+    set +x
+}
+
+curl https://api.github.com/repos/tailscale/go/releases 2>/dev/null |\
+    jq -r '.[] | "\(.published_at) \(.id) \(.tag_name)"' |\
+    egrep '[^ ]+ [^ ]+ build-[0-9a-f]{40}' |\
+    sort |\
+    head --lines=-${KEEP}|\
+    while read date release_id tag_name; do
+        delete_release "$release_id" "$tag_name"
+    done

api/go1.99999.txt

@@ -0,0 +1,10 @@
+pkg net, func SetDialEnforcer(func(context.Context, []Addr) error) #55
+pkg net, func SetResolveEnforcer(func(context.Context, string, string, string, Addr) error) #55
+pkg net, func WithSockTrace(context.Context, *SockTrace) context.Context #58
+pkg net, func ContextSockTrace(context.Context) *SockTrace #58
+pkg net, type SockTrace struct #58
+pkg net, type SockTrace struct, DidRead func(int) #58
+pkg net, type SockTrace struct, DidWrite func(int) #58
+pkg net, type SockTrace struct, WillOverwrite func(*SockTrace) #58
+pkg net, type SockTrace struct, DidCreateTCPConn func(syscall.RawConn) #58
+pkg net, type SockTrace struct, WillCloseTCPConn func(syscall.RawConn) #58

src/cmd/dist/build.go

@@ -393,6 +393,12 @@ func findgoversion() string {
 		// its content if available, which is empty at this point.
 		// Only use the VERSION file if it is non-empty.
 		if b != "" {
+			if rev := os.Getenv("TAILSCALE_TOOLCHAIN_REV"); rev != "" {
+				if len(rev) > 10 {
+					rev = rev[:10]
+				}
+				b += "-ts" + chomp(rev)
+			}
 			return b
 		}
 	}

src/cmd/dist/buildgo.go

@@ -7,7 +7,6 @@ package main
 import (
 	"fmt"
 	"io"
-	"os"
 	"path/filepath"
 	"sort"
 	"strings"
@@ -119,7 +118,7 @@ func mkzcgo(dir, file string) {
 	writeHeader(&buf)
 	fmt.Fprintf(&buf, "package build\n")
 	fmt.Fprintln(&buf)
-	fmt.Fprintf(&buf, "const defaultCGO_ENABLED = %s\n", quote(os.Getenv("CGO_ENABLED")))
+	fmt.Fprintf(&buf, "const defaultCGO_ENABLED = %q\n", "")
 
 	writefile(buf.String(), file, writeSkipSame)
 }

src/net/dial.go

@@ -247,6 +247,24 @@ func parseNetwork(ctx context.Context, network string, needsProto bool) (afnet s
 	return "", 0, UnknownNetworkError(network)
 }
 
+// SetResolveEnforcer set a program-global resolver enforcer that can cause resolvers to
+// fail based on the context and/or other arguments.
+//
+// f must be non-nil, it can only be called once, and must not be called
+// concurrent with any dial/resolve.
+func SetResolveEnforcer(f func(ctx context.Context, op, network, addr string, hint Addr) error) {
+	if f == nil {
+		panic("nil func")
+	}
+	if resolveEnforcer != nil {
+		panic("already called")
+	}
+	resolveEnforcer = f
+}
+
+// resolveEnforcer, if non-nil, is the installed hook from SetResolveEnforcer.
+var resolveEnforcer func(ctx context.Context, op, network, addr string, hint Addr) error
+
 // resolveAddrList resolves addr using hint and returns a list of
 // addresses. The result contains at least one address when error is
 // nil.
@@ -269,6 +287,13 @@ func (r *Resolver) resolveAddrList(ctx context.Context, op, network, addr string
 		}
 		return addrList{addr}, nil
 	}
+
+	if resolveEnforcer != nil {
+		if err := resolveEnforcer(ctx, op, network, addr, hint); err != nil {
+			return nil, err
+		}
+	}
+
 	addrs, err := r.internetAddrList(ctx, afnet, addr)
 	if err != nil || op != "dial" || hint == nil {
 		return addrs, err
@@ -572,9 +597,32 @@ func (sd *sysDialer) dialParallel(ctx context.Context, primaries, fallbacks addr
 	}
 }
 
+// SetDialEnforcer set a program-global dial enforcer that can cause dials to
+// fail based on the context and/or Addr(s).
+//
+// f must be non-nil, it can only be called once, and must not be called
+// concurrent with any dial.
+func SetDialEnforcer(f func(context.Context, []Addr) error) {
+	if f == nil {
+		panic("nil func")
+	}
+	if dialEnforcer != nil {
+		panic("already called")
+	}
+	dialEnforcer = f
+}
+
+// dialEnforce, if non-nil, is any installed hook from SetDialEnforcer.
+var dialEnforcer func(context.Context, []Addr) error
+
 // dialSerial connects to a list of addresses in sequence, returning
 // either the first successful connection, or the first error.
 func (sd *sysDialer) dialSerial(ctx context.Context, ras addrList) (Conn, error) {
+	if dialEnforcer != nil {
+		if err := dialEnforcer(ctx, ras); err != nil {
+			return nil, err
+		}
+	}
 	var firstErr error // The error from the first address is most relevant.
 
 	for i, ra := range ras {