Initialize module and dependencies

vendor/golang.org/x/telemetry/internal/config/config.go

@@ -0,0 +1,140 @@
+// Copyright 2023 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 config provides methods for loading and querying a
+// telemetry upload config file.
+package config
+
+import (
+	"encoding/json"
+	"os"
+	"strings"
+
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+// Config is a wrapper around telemetry.UploadConfig that provides some
+// convenience methods for checking the contents of a report.
+type Config struct {
+	*telemetry.UploadConfig
+	program         map[string]bool
+	goos            map[string]bool
+	goarch          map[string]bool
+	goversion       map[string]bool
+	pgversion       map[pgkey]bool
+	pgcounter       map[pgkey]bool
+	pgcounterprefix map[pgkey]bool
+	pgstack         map[pgkey]bool
+	rate            map[pgkey]float64
+}
+
+type pgkey struct {
+	program, key string
+}
+
+func ReadConfig(file string) (*Config, error) {
+	data, err := os.ReadFile(file)
+	if err != nil {
+		return nil, err
+	}
+	var cfg telemetry.UploadConfig
+	if err := json.Unmarshal(data, &cfg); err != nil {
+		return nil, err
+	}
+	return NewConfig(&cfg), nil
+}
+
+func NewConfig(cfg *telemetry.UploadConfig) *Config {
+	ucfg := Config{UploadConfig: cfg}
+	ucfg.goos = set(ucfg.GOOS)
+	ucfg.goarch = set(ucfg.GOARCH)
+	ucfg.goversion = set(ucfg.GoVersion)
+	ucfg.program = make(map[string]bool, len(ucfg.Programs))
+	ucfg.pgversion = make(map[pgkey]bool, len(ucfg.Programs))
+	ucfg.pgcounter = make(map[pgkey]bool, len(ucfg.Programs))
+	ucfg.pgcounterprefix = make(map[pgkey]bool, len(ucfg.Programs))
+	ucfg.pgstack = make(map[pgkey]bool, len(ucfg.Programs))
+	ucfg.rate = make(map[pgkey]float64)
+	for _, p := range ucfg.Programs {
+		ucfg.program[p.Name] = true
+		for _, v := range p.Versions {
+			ucfg.pgversion[pgkey{p.Name, v}] = true
+		}
+		for _, c := range p.Counters {
+			for _, e := range Expand(c.Name) {
+				ucfg.pgcounter[pgkey{p.Name, e}] = true
+				ucfg.rate[pgkey{p.Name, e}] = c.Rate
+			}
+			prefix, _, found := strings.Cut(c.Name, ":")
+			if found {
+				ucfg.pgcounterprefix[pgkey{p.Name, prefix}] = true
+			}
+		}
+		for _, s := range p.Stacks {
+			ucfg.pgstack[pgkey{p.Name, s.Name}] = true
+			ucfg.rate[pgkey{p.Name, s.Name}] = s.Rate
+		}
+	}
+	return &ucfg
+}
+
+func (r *Config) HasProgram(s string) bool {
+	return r.program[s]
+}
+
+func (r *Config) HasGOOS(s string) bool {
+	return r.goos[s]
+}
+
+func (r *Config) HasGOARCH(s string) bool {
+	return r.goarch[s]
+}
+
+func (r *Config) HasGoVersion(s string) bool {
+	return r.goversion[s]
+}
+
+func (r *Config) HasVersion(program, version string) bool {
+	return r.pgversion[pgkey{program, version}]
+}
+
+func (r *Config) HasCounter(program, counter string) bool {
+	return r.pgcounter[pgkey{program, counter}]
+}
+
+func (r *Config) HasCounterPrefix(program, prefix string) bool {
+	return r.pgcounterprefix[pgkey{program, prefix}]
+}
+
+func (r *Config) HasStack(program, stack string) bool {
+	return r.pgstack[pgkey{program, stack}]
+}
+
+func (r *Config) Rate(program, name string) float64 {
+	return r.rate[pgkey{program, name}]
+}
+
+func set(slice []string) map[string]bool {
+	s := make(map[string]bool, len(slice))
+	for _, v := range slice {
+		s[v] = true
+	}
+	return s
+}
+
+// Expand takes a counter defined with buckets and expands it into distinct
+// strings for each bucket.
+func Expand(counter string) []string {
+	prefix, rest, hasBuckets := strings.Cut(counter, "{")
+	var counters []string
+	if hasBuckets {
+		buckets := strings.Split(strings.TrimSuffix(rest, "}"), ",")
+		for _, b := range buckets {
+			counters = append(counters, prefix+b)
+		}
+	} else {
+		counters = append(counters, prefix)
+	}
+	return counters
+}

vendor/golang.org/x/telemetry/internal/configstore/download.go

@@ -0,0 +1,86 @@
+// Copyright 2023 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 configstore abstracts interaction with the telemetry config server.
+// Telemetry config (golang.org/x/telemetry/config) is distributed as a go
+// module containing go.mod and config.json. Programs that upload collected
+// counters download the latest config using `go mod download`. This provides
+// verification of downloaded configuration and cacheability.
+package configstore
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sync/atomic"
+
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+const (
+	ModulePath     = "golang.org/x/telemetry/config"
+	configFileName = "config.json"
+)
+
+// needNoConsole is used on windows to set the windows.CREATE_NO_WINDOW
+// creation flag.
+var needNoConsole = func(cmd *exec.Cmd) {}
+
+var downloads int64
+
+// Downloads reports, for testing purposes, the number of times [Download] has
+// been called.
+func Downloads() int64 {
+	return atomic.LoadInt64(&downloads)
+}
+
+// Download fetches the requested telemetry UploadConfig using "go mod
+// download". If envOverlay is provided, it is appended to the environment used
+// for invoking the go command.
+//
+// The second result is the canonical version of the requested configuration.
+func Download(version string, envOverlay []string) (*telemetry.UploadConfig, string, error) {
+	atomic.AddInt64(&downloads, 1)
+
+	if version == "" {
+		version = "latest"
+	}
+	modVer := ModulePath + "@" + version
+	var stdout, stderr bytes.Buffer
+	cmd := exec.Command("go", "mod", "download", "-json", modVer)
+	needNoConsole(cmd)
+	cmd.Env = append(os.Environ(), envOverlay...)
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	if err := cmd.Run(); err != nil {
+		var info struct {
+			Error string
+		}
+		if err := json.Unmarshal(stdout.Bytes(), &info); err == nil && info.Error != "" {
+			return nil, "", fmt.Errorf("failed to download config module: %v", info.Error)
+		}
+		return nil, "", fmt.Errorf("failed to download config module: %w\n%s", err, &stderr)
+	}
+
+	var info struct {
+		Dir     string
+		Version string
+		Error   string
+	}
+	if err := json.Unmarshal(stdout.Bytes(), &info); err != nil || info.Dir == "" {
+		return nil, "", fmt.Errorf("failed to download config module (invalid JSON): %w", err)
+	}
+	data, err := os.ReadFile(filepath.Join(info.Dir, configFileName))
+	if err != nil {
+		return nil, "", fmt.Errorf("invalid config module: %w", err)
+	}
+	cfg := new(telemetry.UploadConfig)
+	if err := json.Unmarshal(data, cfg); err != nil {
+		return nil, "", fmt.Errorf("invalid config: %w", err)
+	}
+	return cfg, info.Version, nil
+}

vendor/golang.org/x/telemetry/internal/configstore/download_windows.go

@@ -0,0 +1,33 @@
+// Copyright 2024 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.
+
+//go:build windows
+
+package configstore
+
+import (
+	"os/exec"
+	"syscall"
+
+	"golang.org/x/sys/windows"
+)
+
+func init() {
+	needNoConsole = needNoConsoleWindows
+}
+
+func needNoConsoleWindows(cmd *exec.Cmd) {
+	// The uploader main process is likely a daemonized process with no console.
+	// (see x/telemetry/start_windows.go) The console creation behavior when
+	// a parent is a console process without console is not clearly documented
+	// but empirically we observed the new console is created and attached to the
+	// subprocess in the default setup.
+	//
+	// Ensure no new console is attached to the subprocess by setting CREATE_NO_WINDOW.
+	//   https://learn.microsoft.com/en-us/windows/console/creation-of-a-console
+	//   https://learn.microsoft.com/en-us/windows/win32/procthread/process-creation-flags
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		CreationFlags: windows.CREATE_NO_WINDOW,
+	}
+}

vendor/golang.org/x/telemetry/internal/counter/counter.go

@@ -0,0 +1,401 @@
+// Copyright 2023 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 internal/counter implements the internals of the public counter package.
+// In addition to the public API, this package also includes APIs to parse and
+// manage the counter files, needed by the upload package.
+package counter
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"strings"
+	"sync/atomic"
+)
+
+var (
+	// Note: not using internal/godebug, so that internal/godebug can use
+	// internal/counter.
+	debugCounter = strings.Contains(os.Getenv("GODEBUG"), "countertrace=1")
+	CrashOnBugs  = false // for testing; if set, exit on fatal log messages
+)
+
+// debugPrintf formats a debug message if GODEBUG=countertrace=1.
+func debugPrintf(format string, args ...any) {
+	if debugCounter {
+		if len(format) == 0 || format[len(format)-1] != '\n' {
+			format += "\n"
+		}
+		fmt.Fprintf(os.Stderr, "counter: "+format, args...)
+	}
+}
+
+// debugFatalf logs a fatal error if GODEBUG=countertrace=1.
+func debugFatalf(format string, args ...any) {
+	if debugCounter || CrashOnBugs {
+		if len(format) == 0 || format[len(format)-1] != '\n' {
+			format += "\n"
+		}
+		fmt.Fprintf(os.Stderr, "counter bug: "+format, args...)
+		os.Exit(1)
+	}
+}
+
+// A Counter is a single named event counter.
+// A Counter is safe for use by multiple goroutines simultaneously.
+//
+// Counters should typically be created using New
+// and stored as global variables, like:
+//
+//	package mypackage
+//	var errorCount = counter.New("mypackage/errors")
+//
+// (The initialization of errorCount in this example is handled
+// entirely by the compiler and linker; this line executes no code
+// at program startup.)
+//
+// Then code can call Add to increment the counter
+// each time the corresponding event is observed.
+//
+// Although it is possible to use New to create
+// a Counter each time a particular event needs to be recorded,
+// that usage fails to amortize the construction cost over
+// multiple calls to Add, so it is more expensive and not recommended.
+type Counter struct {
+	name string
+	file *file
+
+	next  atomic.Pointer[Counter]
+	state counterState
+	ptr   counterPtr
+}
+
+func (c *Counter) Name() string {
+	return c.name
+}
+
+type counterPtr struct {
+	m     *mappedFile
+	count *atomic.Uint64
+}
+
+type counterState struct {
+	bits atomic.Uint64
+}
+
+func (s *counterState) load() counterStateBits {
+	return counterStateBits(s.bits.Load())
+}
+
+func (s *counterState) update(old *counterStateBits, new counterStateBits) bool {
+	if s.bits.CompareAndSwap(uint64(*old), uint64(new)) {
+		*old = new
+		return true
+	}
+	return false
+}
+
+type counterStateBits uint64
+
+const (
+	stateReaders    counterStateBits = 1<<30 - 1
+	stateLocked     counterStateBits = stateReaders
+	stateHavePtr    counterStateBits = 1 << 30
+	stateExtraShift                  = 31
+	stateExtra      counterStateBits = 1<<64 - 1<<stateExtraShift
+)
+
+func (b counterStateBits) readers() int  { return int(b & stateReaders) }
+func (b counterStateBits) locked() bool  { return b&stateReaders == stateLocked }
+func (b counterStateBits) havePtr() bool { return b&stateHavePtr != 0 }
+func (b counterStateBits) extra() uint64 { return uint64(b&stateExtra) >> stateExtraShift }
+
+func (b counterStateBits) incReader() counterStateBits    { return b + 1 }
+func (b counterStateBits) decReader() counterStateBits    { return b - 1 }
+func (b counterStateBits) setLocked() counterStateBits    { return b | stateLocked }
+func (b counterStateBits) clearLocked() counterStateBits  { return b &^ stateLocked }
+func (b counterStateBits) setHavePtr() counterStateBits   { return b | stateHavePtr }
+func (b counterStateBits) clearHavePtr() counterStateBits { return b &^ stateHavePtr }
+func (b counterStateBits) clearExtra() counterStateBits   { return b &^ stateExtra }
+func (b counterStateBits) addExtra(n uint64) counterStateBits {
+	const maxExtra = uint64(stateExtra) >> stateExtraShift // 0x1ffffffff
+	x := b.extra()
+	if x+n < x || x+n > maxExtra {
+		x = maxExtra
+	} else {
+		x += n
+	}
+	return b.clearExtra() | counterStateBits(x)<<stateExtraShift
+}
+
+// New returns a counter with the given name.
+// New can be called in global initializers and will be compiled down to
+// linker-initialized data. That is, calling New to initialize a global
+// has no cost at program startup.
+func New(name string) *Counter {
+	// Note: not calling defaultFile.New in order to keep this
+	// function something the compiler can inline and convert
+	// into static data initializations, with no init-time footprint.
+	return &Counter{name: name, file: &defaultFile}
+}
+
+// Inc adds 1 to the counter.
+func (c *Counter) Inc() {
+	c.Add(1)
+}
+
+// Add adds n to the counter. n cannot be negative, as counts cannot decrease.
+func (c *Counter) Add(n int64) {
+	debugPrintf("Add %q += %d", c.name, n)
+
+	if n < 0 {
+		panic("Counter.Add negative")
+	}
+	if n == 0 {
+		return
+	}
+	c.file.register(c)
+
+	state := c.state.load()
+	for ; ; state = c.state.load() {
+		switch {
+		case !state.locked() && state.havePtr():
+			if !c.state.update(&state, state.incReader()) {
+				continue
+			}
+			// Counter unlocked or counter shared; has an initialized count pointer; acquired shared lock.
+			if c.ptr.count == nil {
+				for !c.state.update(&state, state.addExtra(uint64(n))) {
+					// keep trying - we already took the reader lock
+					state = c.state.load()
+				}
+				debugPrintf("Add %q += %d: nil extra=%d\n", c.name, n, state.extra())
+			} else {
+				sum := c.add(uint64(n))
+				debugPrintf("Add %q += %d: count=%d\n", c.name, n, sum)
+			}
+			c.releaseReader(state)
+			return
+
+		case state.locked():
+			if !c.state.update(&state, state.addExtra(uint64(n))) {
+				continue
+			}
+			debugPrintf("Add %q += %d: locked extra=%d\n", c.name, n, state.extra())
+			return
+
+		case !state.havePtr():
+			if !c.state.update(&state, state.addExtra(uint64(n)).setLocked()) {
+				continue
+			}
+			debugPrintf("Add %q += %d: noptr extra=%d\n", c.name, n, state.extra())
+			c.releaseLock(state)
+			return
+		}
+	}
+}
+
+func (c *Counter) releaseReader(state counterStateBits) {
+	for ; ; state = c.state.load() {
+		// If we are the last reader and havePtr was cleared
+		// while this batch of readers was using c.ptr,
+		// it's our job to update c.ptr by upgrading to a full lock
+		// and letting releaseLock do the work.
+		// Note: no new reader will attempt to add itself now that havePtr is clear,
+		// so we are only racing against possible additions to extra.
+		if state.readers() == 1 && !state.havePtr() {
+			if !c.state.update(&state, state.setLocked()) {
+				continue
+			}
+			debugPrintf("releaseReader %s: last reader, need ptr\n", c.name)
+			c.releaseLock(state)
+			return
+		}
+
+		// Release reader.
+		if !c.state.update(&state, state.decReader()) {
+			continue
+		}
+		debugPrintf("releaseReader %s: released (%d readers now)\n", c.name, state.readers())
+		return
+	}
+}
+
+func (c *Counter) releaseLock(state counterStateBits) {
+	for ; ; state = c.state.load() {
+		if !state.havePtr() {
+			// Set havePtr before updating ptr,
+			// to avoid race with the next clear of havePtr.
+			if !c.state.update(&state, state.setHavePtr()) {
+				continue
+			}
+			debugPrintf("releaseLock %s: reset havePtr (extra=%d)\n", c.name, state.extra())
+
+			// Optimization: only bother loading a new pointer
+			// if we have a value to add to it.
+			c.ptr = counterPtr{nil, nil}
+			if state.extra() != 0 {
+				c.ptr = c.file.lookup(c.name)
+				debugPrintf("releaseLock %s: ptr=%v\n", c.name, c.ptr)
+			}
+		}
+
+		if extra := state.extra(); extra != 0 && c.ptr.count != nil {
+			if !c.state.update(&state, state.clearExtra()) {
+				continue
+			}
+			sum := c.add(extra)
+			debugPrintf("releaseLock %s: flush extra=%d -> count=%d\n", c.name, extra, sum)
+		}
+
+		// Took care of refreshing ptr and flushing extra.
+		// Now we can release the lock, unless of course
+		// another goroutine cleared havePtr or added to extra,
+		// in which case we go around again.
+		if !c.state.update(&state, state.clearLocked()) {
+			continue
+		}
+		debugPrintf("releaseLock %s: unlocked\n", c.name)
+		return
+	}
+}
+
+// add wraps the atomic.Uint64.Add operation to handle integer overflow.
+func (c *Counter) add(n uint64) uint64 {
+	count := c.ptr.count
+	for {
+		old := count.Load()
+		sum := old + n
+		if sum < old {
+			sum = ^uint64(0)
+		}
+		if count.CompareAndSwap(old, sum) {
+			runtime.KeepAlive(c.ptr.m)
+			return sum
+		}
+	}
+}
+
+func (c *Counter) invalidate() {
+	for {
+		state := c.state.load()
+		if !state.havePtr() {
+			debugPrintf("invalidate %s: no ptr\n", c.name)
+			return
+		}
+		if c.state.update(&state, state.clearHavePtr()) {
+			debugPrintf("invalidate %s: cleared havePtr\n", c.name)
+			return
+		}
+	}
+}
+
+func (c *Counter) refresh() {
+	for {
+		state := c.state.load()
+		if state.havePtr() || state.readers() > 0 || state.extra() == 0 {
+			debugPrintf("refresh %s: havePtr=%v readers=%d extra=%d\n", c.name, state.havePtr(), state.readers(), state.extra())
+			return
+		}
+		if c.state.update(&state, state.setLocked()) {
+			debugPrintf("refresh %s: locked havePtr=%v readers=%d extra=%d\n", c.name, state.havePtr(), state.readers(), state.extra())
+			c.releaseLock(state)
+			return
+		}
+	}
+}
+
+// Read reads the given counter.
+// This is the implementation of x/telemetry/counter/countertest.ReadCounter.
+func Read(c *Counter) (uint64, error) {
+	if c.file.current.Load() == nil {
+		return c.state.load().extra(), nil
+	}
+	pf, err := readFile(c.file)
+	if err != nil {
+		return 0, err
+	}
+	v, ok := pf.Count[DecodeStack(c.Name())]
+	if !ok {
+		return v, fmt.Errorf("not found:%q", DecodeStack(c.Name()))
+	}
+	return v, nil
+}
+
+func readFile(f *file) (*File, error) {
+	if f == nil {
+		debugPrintf("No file")
+		return nil, fmt.Errorf("counter is not initialized - was Open called?")
+	}
+
+	// Note: don't call f.rotate here as this will enqueue a follow-up rotation.
+	f.rotate1()
+
+	if f.err != nil {
+		return nil, fmt.Errorf("failed to rotate mapped file - %v", f.err)
+	}
+	current := f.current.Load()
+	if current == nil {
+		return nil, fmt.Errorf("counter has no mapped file")
+	}
+	name := current.f.Name()
+	data, err := ReadMapped(name)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read from file: %v", err)
+	}
+	pf, err := Parse(name, data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse: %v", err)
+	}
+	return pf, nil
+}
+
+// ReadFile reads the counters and stack counters from the given file.
+// This is the implementation of x/telemetry/counter/countertest.ReadFile.
+func ReadFile(name string) (counters, stackCounters map[string]uint64, _ error) {
+	// TODO: Document the format of the stackCounters names.
+
+	data, err := ReadMapped(name)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to read from file: %v", err)
+	}
+	pf, err := Parse(name, data)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to parse: %v", err)
+	}
+	counters = make(map[string]uint64)
+	stackCounters = make(map[string]uint64)
+	for k, v := range pf.Count {
+		if IsStackCounter(k) {
+			stackCounters[DecodeStack(k)] = v
+		} else {
+			counters[k] = v
+		}
+	}
+	return counters, stackCounters, nil
+}
+
+// ReadMapped reads the contents of the given file by memory mapping.
+//
+// This avoids file synchronization issues.
+func ReadMapped(name string) ([]byte, error) {
+	f, err := os.OpenFile(name, os.O_RDWR, 0666)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	fi, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	mapping, err := memmap(f)
+	if err != nil {
+		return nil, err
+	}
+	data := make([]byte, fi.Size())
+	copy(data, mapping.Data)
+	munmap(mapping)
+	return data, nil
+}

vendor/golang.org/x/telemetry/internal/counter/file.go

@@ -0,0 +1,814 @@
+// Copyright 2023 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 counter
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"math/rand"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime"
+	"runtime/debug"
+	"sync"
+	"sync/atomic"
+	"time"
+	"unsafe"
+
+	"golang.org/x/telemetry/internal/mmap"
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+// A file is a counter file.
+type file struct {
+	// Linked list of all known counters.
+	// (Linked list insertion is easy to make lock-free,
+	// and we don't want the initial counters incremented
+	// by a program to cause significant contention.)
+	counters atomic.Pointer[Counter] // head of list
+	end      Counter                 // list ends at &end instead of nil
+
+	mu                 sync.Mutex
+	buildInfo          *debug.BuildInfo
+	timeBegin, timeEnd time.Time
+	err                error
+	// current holds the current file mapping, which may change when the file is
+	// rotated or extended.
+	//
+	// current may be read without holding mu, but may be nil.
+	//
+	// The cleanup logic for file mappings is complicated, because invalidating
+	// counter pointers is reentrant: [file.invalidateCounters] may call
+	// [file.lookup], which acquires mu. Therefore, writing current must be done
+	// as follows:
+	//  1. record the previous value of current
+	//  2. Store a new value in current
+	//  3. unlock mu
+	//  4. call invalidateCounters
+	//  5. close the previous mapped value from (1)
+	// TODO(rfindley): simplify
+	current atomic.Pointer[mappedFile]
+}
+
+var defaultFile file
+
+// register ensures that the counter c is registered with the file.
+func (f *file) register(c *Counter) {
+	debugPrintf("register %s %p\n", c.Name(), c)
+
+	// If counter is not registered with file, register it.
+	// Doing this lazily avoids init-time work
+	// as well as any execution cost at all for counters
+	// that are not used in a given program.
+	wroteNext := false
+	for wroteNext || c.next.Load() == nil {
+		head := f.counters.Load()
+		next := head
+		if next == nil {
+			next = &f.end
+		}
+		debugPrintf("register %s next %p\n", c.Name(), next)
+		if !wroteNext {
+			if !c.next.CompareAndSwap(nil, next) {
+				debugPrintf("register %s cas failed %p\n", c.Name(), c.next.Load())
+				continue
+			}
+			wroteNext = true
+		} else {
+			c.next.Store(next)
+		}
+		if f.counters.CompareAndSwap(head, c) {
+			debugPrintf("registered %s %p\n", c.Name(), f.counters.Load())
+			return
+		}
+		debugPrintf("register %s cas2 failed %p %p\n", c.Name(), f.counters.Load(), head)
+	}
+}
+
+// invalidateCounters marks as invalid all the pointers
+// held by f's counters and then refreshes them.
+//
+// invalidateCounters cannot be called while holding f.mu,
+// because a counter refresh may call f.lookup.
+func (f *file) invalidateCounters() {
+	// Mark every counter as needing to refresh its count pointer.
+	if head := f.counters.Load(); head != nil {
+		for c := head; c != &f.end; c = c.next.Load() {
+			c.invalidate()
+		}
+		for c := head; c != &f.end; c = c.next.Load() {
+			c.refresh()
+		}
+	}
+}
+
+// lookup looks up the counter with the given name in the file,
+// allocating it if needed, and returns a pointer to the atomic.Uint64
+// containing the counter data.
+// If the file has not been opened yet, lookup returns nil.
+func (f *file) lookup(name string) counterPtr {
+	current := f.current.Load()
+	if current == nil {
+		debugPrintf("lookup %s - no mapped file\n", name)
+		return counterPtr{}
+	}
+	ptr := f.newCounter(name)
+	if ptr == nil {
+		return counterPtr{}
+	}
+	return counterPtr{current, ptr}
+}
+
+// ErrDisabled is the error returned when telemetry is disabled.
+var ErrDisabled = errors.New("counter: disabled as Go telemetry is off")
+
+var (
+	errNoBuildInfo = errors.New("counter: missing build info")
+	errCorrupt     = errors.New("counter: corrupt counter file")
+)
+
+// weekEnd returns the day of the week on which uploads occur (and therefore
+// counters expire).
+//
+// Reads the weekends file, creating one if none exists.
+func weekEnd() (time.Weekday, error) {
+	// If there is no 'weekends' file create it and initialize it
+	// to a random day of the week. There is a short interval for
+	// a race.
+	weekends := filepath.Join(telemetry.Default.LocalDir(), "weekends")
+	day := fmt.Sprintf("%d\n", rand.Intn(7))
+	if _, err := os.ReadFile(weekends); err != nil {
+		if err := os.MkdirAll(telemetry.Default.LocalDir(), 0777); err != nil {
+			debugPrintf("%v: could not create telemetry.LocalDir %s", err, telemetry.Default.LocalDir())
+			return 0, err
+		}
+		if err = os.WriteFile(weekends, []byte(day), 0666); err != nil {
+			return 0, err
+		}
+	}
+
+	// race is over, read the file
+	buf, err := os.ReadFile(weekends)
+	// There is no reasonable way of recovering from errors
+	// so we just fail
+	if err != nil {
+		return 0, err
+	}
+	buf = bytes.TrimSpace(buf)
+	if len(buf) == 0 {
+		return 0, fmt.Errorf("empty weekends file")
+	}
+	weekend := time.Weekday(buf[0] - '0') // 0 is Sunday
+	// paranoia to make sure the value is legal
+	weekend %= 7
+	if weekend < 0 {
+		weekend += 7
+	}
+	return weekend, nil
+}
+
+// rotate checks to see whether the file f needs to be rotated,
+// meaning to start a new counter file with a different date in the name.
+// rotate is also used to open the file initially, meaning f.current can be nil.
+// In general rotate should be called just once for each file.
+// rotate will arrange a timer to call itself again when necessary.
+func (f *file) rotate() {
+	expiry := f.rotate1()
+	if !expiry.IsZero() {
+		delay := time.Until(expiry)
+		// Some tests set CounterTime to a time in the past, causing delay to be
+		// negative. Avoid infinite loops by delaying at least a short interval.
+		//
+		// TODO(rfindley): instead, just also mock AfterFunc.
+		const minDelay = 1 * time.Minute
+		if delay < minDelay {
+			delay = minDelay
+		}
+		// TODO(rsc): Does this do the right thing for laptops closing?
+		time.AfterFunc(delay, f.rotate)
+	}
+}
+
+func nop() {}
+
+// CounterTime returns the current UTC time.
+// Mutable for testing.
+var CounterTime = func() time.Time {
+	return time.Now().UTC()
+}
+
+// counterSpan returns the current time span for a counter file, as determined
+// by [CounterTime] and the [weekEnd].
+func counterSpan() (begin, end time.Time, _ error) {
+	year, month, day := CounterTime().Date()
+	begin = time.Date(year, month, day, 0, 0, 0, 0, time.UTC)
+	// files always begin today, but expire on the next day of the week
+	// from the 'weekends' file.
+	weekend, err := weekEnd()
+	if err != nil {
+		return time.Time{}, time.Time{}, err
+	}
+	incr := int(weekend - begin.Weekday())
+	if incr <= 0 {
+		incr += 7 // ensure that end is later than begin
+	}
+	end = time.Date(year, month, day+incr, 0, 0, 0, 0, time.UTC)
+	return begin, end, nil
+}
+
+// rotate1 rotates the current counter file, returning its expiry, or the zero
+// time if rotation failed.
+func (f *file) rotate1() time.Time {
+	// Cleanup must be performed while unlocked, since invalidateCounters may
+	// involve calls to f.lookup.
+	var previous *mappedFile // read below while holding the f.mu.
+	defer func() {
+		// Counters must be invalidated whenever the mapped file changes.
+		if next := f.current.Load(); next != previous {
+			f.invalidateCounters()
+			// Ensure that the previous counter mapped file is closed.
+			if previous != nil {
+				previous.close() // safe to call multiple times
+			}
+		}
+	}()
+
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	previous = f.current.Load()
+
+	if f.err != nil {
+		return time.Time{} // already in failed state; nothing to do
+	}
+
+	fail := func(err error) {
+		debugPrintf("rotate: %v", err)
+		f.err = err
+		f.current.Store(nil)
+	}
+
+	if mode, _ := telemetry.Default.Mode(); mode == "off" {
+		// TODO(rfindley): do we ever want to make ErrDisabled recoverable?
+		// Specifically, if f.err is ErrDisabled, should we check again during when
+		// rotating?
+		fail(ErrDisabled)
+		return time.Time{}
+	}
+
+	if f.buildInfo == nil {
+		bi, ok := debug.ReadBuildInfo()
+		if !ok {
+			fail(errNoBuildInfo)
+			return time.Time{}
+		}
+		f.buildInfo = bi
+	}
+
+	begin, end, err := counterSpan()
+	if err != nil {
+		fail(err)
+		return time.Time{}
+	}
+	if f.timeBegin.Equal(begin) && f.timeEnd.Equal(end) {
+		return f.timeEnd // nothing to do
+	}
+	f.timeBegin, f.timeEnd = begin, end
+
+	goVers, progPath, progVers := telemetry.ProgramInfo(f.buildInfo)
+	meta := fmt.Sprintf("TimeBegin: %s\nTimeEnd: %s\nProgram: %s\nVersion: %s\nGoVersion: %s\nGOOS: %s\nGOARCH: %s\n\n",
+		f.timeBegin.Format(time.RFC3339), f.timeEnd.Format(time.RFC3339),
+		progPath, progVers, goVers, runtime.GOOS, runtime.GOARCH)
+	if len(meta) > maxMetaLen { // should be impossible for our use
+		fail(fmt.Errorf("metadata too long"))
+		return time.Time{}
+	}
+
+	if progVers != "" {
+		progVers = "@" + progVers
+	}
+	baseName := fmt.Sprintf("%s%s-%s-%s-%s-%s.%s.count",
+		path.Base(progPath),
+		progVers,
+		goVers,
+		runtime.GOOS,
+		runtime.GOARCH,
+		f.timeBegin.Format(telemetry.DateOnly),
+		FileVersion,
+	)
+	dir := telemetry.Default.LocalDir()
+	if err := os.MkdirAll(dir, 0777); err != nil {
+		fail(fmt.Errorf("making local dir: %v", err))
+		return time.Time{}
+	}
+	name := filepath.Join(dir, baseName)
+
+	m, err := openMapped(name, meta)
+	if err != nil {
+		// Mapping failed:
+		// If there used to be a mapped file, after cleanup
+		// incrementing counters will only change their internal state.
+		// (before cleanup the existing mapped file would be updated)
+		fail(fmt.Errorf("openMapped: %v", err))
+		return time.Time{}
+	}
+
+	debugPrintf("using %v", m.f.Name())
+	f.current.Store(m)
+	return f.timeEnd
+}
+
+func (f *file) newCounter(name string) *atomic.Uint64 {
+	v, cleanup := f.newCounter1(name)
+	cleanup()
+	return v
+}
+
+func (f *file) newCounter1(name string) (v *atomic.Uint64, cleanup func()) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	current := f.current.Load()
+	if current == nil {
+		return nil, nop
+	}
+	debugPrintf("newCounter %s in %s\n", name, current.f.Name())
+	if v, _, _, _ := current.lookup(name); v != nil {
+		return v, nop
+	}
+	v, newM, err := current.newCounter(name)
+	if err != nil {
+		debugPrintf("newCounter %s: %v\n", name, err)
+		return nil, nop
+	}
+
+	cleanup = nop
+	if newM != nil {
+		f.current.Store(newM)
+		cleanup = func() {
+			f.invalidateCounters()
+			current.close()
+		}
+	}
+	return v, cleanup
+}
+
+var (
+	openOnce sync.Once
+	// rotating reports whether the call to Open had rotate = true.
+	//
+	// In golang/go#68497, we observed that file rotation can break runtime
+	// deadlock detection. To minimize the fix for 1.23, we are splitting the
+	// Open API into one version that rotates the counter file, and another that
+	// does not. The rotating variable guards against use of both APIs from the
+	// same process.
+	rotating bool
+)
+
+// Open associates counting with the defaultFile.
+// The returned function is for testing only, and should
+// be called after all Inc()s are finished, but before
+// any reports are generated.
+// (Otherwise expired count files will not be deleted on Windows.)
+func Open(rotate bool) func() {
+	if telemetry.DisabledOnPlatform {
+		return func() {}
+	}
+	close := func() {}
+	openOnce.Do(func() {
+		rotating = rotate
+		if mode, _ := telemetry.Default.Mode(); mode == "off" {
+			// Don't open the file when telemetry is off.
+			defaultFile.err = ErrDisabled
+			// No need to clean up.
+			return
+		}
+		debugPrintf("Open(%v)", rotate)
+		if rotate {
+			defaultFile.rotate() // calls rotate1 and schedules a rotation
+		} else {
+			defaultFile.rotate1()
+		}
+		close = func() {
+			// Once this has been called, the defaultFile is no longer usable.
+			mf := defaultFile.current.Load()
+			if mf == nil {
+				// telemetry might have been off
+				return
+			}
+			mf.close()
+		}
+	})
+	if rotating != rotate {
+		panic("BUG: Open called with inconsistent values for 'rotate'")
+	}
+	return close
+}
+
+const (
+	FileVersion = "v1"
+	hdrPrefix   = "# telemetry/counter file " + FileVersion + "\n"
+	recordUnit  = 32
+	maxMetaLen  = 512
+	numHash     = 512 // 2kB for hash table
+	maxNameLen  = 4 * 1024
+	limitOff    = 0
+	hashOff     = 4
+	pageSize    = 16 * 1024
+	minFileLen  = 16 * 1024
+)
+
+// A mappedFile is a counter file mmapped into memory.
+//
+// The file layout for a mappedFile m is as follows:
+//
+//	offset, byte size:                 description
+//	------------------                 -----------
+//	0, hdrLen:                         header, containing metadata; see [mappedHeader]
+//	hdrLen+limitOff, 4:                uint32 allocation limit (byte offset of the end of counter records)
+//	hdrLen+hashOff, 4*numHash:         hash table, stores uint32 heads of a linked list of records, keyed by name hash
+//	hdrLen+hashOff+4*numHash to limit: counter records: see record syntax below
+//
+// The record layout is as follows:
+//
+//	offset, byte size: description
+//	------------------ -----------
+//	0, 8:              uint64 counter value
+//	8, 12:             uint32 name length
+//	12, 16:            uint32 offset of next record in linked list
+//	16, name length:   counter name
+type mappedFile struct {
+	meta      string
+	hdrLen    uint32
+	zero      [4]byte
+	closeOnce sync.Once
+	f         *os.File
+	mapping   *mmap.Data
+}
+
+// openMapped opens and memory maps a file.
+//
+// name is the path to the file.
+//
+// meta is the file metadata, which must match the metadata of the file on disk
+// exactly.
+//
+// existing should be nil the first time this is called for a file,
+// and when remapping, should be the previous mappedFile.
+func openMapped(name, meta string) (_ *mappedFile, err error) {
+	hdr, err := mappedHeader(meta)
+	if err != nil {
+		return nil, err
+	}
+
+	f, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE, 0666)
+	if err != nil {
+		return nil, err
+	}
+	// Note: using local variable m here, not return value,
+	// so that return nil, err does not set m = nil and break the code in the defer.
+	m := &mappedFile{
+		f:    f,
+		meta: meta,
+	}
+
+	defer func() {
+		if err != nil {
+			m.close()
+		}
+	}()
+
+	info, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	// Establish file header and initial data area if not already present.
+	if info.Size() < minFileLen {
+		if _, err := f.WriteAt(hdr, 0); err != nil {
+			return nil, err
+		}
+		// Write zeros at the end of the file to extend it to minFileLen.
+		if _, err := f.WriteAt(m.zero[:], int64(minFileLen-len(m.zero))); err != nil {
+			return nil, err
+		}
+		info, err = f.Stat()
+		if err != nil {
+			return nil, err
+		}
+		if info.Size() < minFileLen {
+			return nil, fmt.Errorf("counter: writing file did not extend it")
+		}
+	}
+
+	// Map into memory.
+	mapping, err := memmap(f)
+	if err != nil {
+		return nil, err
+	}
+	m.mapping = mapping
+	if !bytes.HasPrefix(m.mapping.Data, hdr) {
+		// TODO(rfindley): we can and should do better here, reading the mapped
+		// header length and comparing headers exactly.
+		return nil, fmt.Errorf("counter: header mismatch")
+	}
+	m.hdrLen = uint32(len(hdr))
+
+	return m, nil
+}
+
+func mappedHeader(meta string) ([]byte, error) {
+	if len(meta) > maxMetaLen {
+		return nil, fmt.Errorf("counter: metadata too large")
+	}
+	np := round(len(hdrPrefix), 4)
+	n := round(np+4+len(meta), 32)
+	hdr := make([]byte, n)
+	copy(hdr, hdrPrefix)
+	*(*uint32)(unsafe.Pointer(&hdr[np])) = uint32(n)
+	copy(hdr[np+4:], meta)
+	return hdr, nil
+}
+
+func (m *mappedFile) place(limit uint32, name string) (start, end uint32) {
+	if limit == 0 {
+		// first record in file
+		limit = m.hdrLen + hashOff + 4*numHash
+	}
+	n := round(uint32(16+len(name)), recordUnit)
+	start = round(limit, recordUnit) // should already be rounded but just in case
+	// Note: Checking for crossing a page boundary would be
+	// start/pageSize != (start+n-1)/pageSize,
+	// but we are checking for reaching the page end, so no -1.
+	// The page end is reserved for use by extend.
+	// See the comment in m.extend.
+	if start/pageSize != (start+n)/pageSize {
+		// bump start to next page
+		start = round(limit, pageSize)
+	}
+	return start, start + n
+}
+
+var memmap = mmap.Mmap
+var munmap = mmap.Munmap
+
+func (m *mappedFile) close() {
+	m.closeOnce.Do(func() {
+		if m.mapping != nil {
+			munmap(m.mapping)
+			m.mapping = nil
+		}
+		if m.f != nil {
+			m.f.Close() // best effort
+			m.f = nil
+		}
+	})
+}
+
+// hash returns the hash code for name.
+// The implementation is FNV-1a.
+// This hash function is a fixed detail of the file format.
+// It cannot be changed without also changing the file format version.
+func hash(name string) uint32 {
+	const (
+		offset32 = 2166136261
+		prime32  = 16777619
+	)
+	h := uint32(offset32)
+	for i := 0; i < len(name); i++ {
+		c := name[i]
+		h = (h ^ uint32(c)) * prime32
+	}
+	return (h ^ (h >> 16)) % numHash
+}
+
+func (m *mappedFile) load32(off uint32) uint32 {
+	if int64(off) >= int64(len(m.mapping.Data)) {
+		return 0
+	}
+	return (*atomic.Uint32)(unsafe.Pointer(&m.mapping.Data[off])).Load()
+}
+
+func (m *mappedFile) cas32(off, old, new uint32) bool {
+	if int64(off) >= int64(len(m.mapping.Data)) {
+		panic("bad cas32") // return false would probably loop
+	}
+	return (*atomic.Uint32)(unsafe.Pointer(&m.mapping.Data[off])).CompareAndSwap(old, new)
+}
+
+// entryAt reads a counter record at the given byte offset.
+//
+// See the documentation for [mappedFile] for a description of the counter record layout.
+func (m *mappedFile) entryAt(off uint32) (name []byte, next uint32, v *atomic.Uint64, ok bool) {
+	if off < m.hdrLen+hashOff || int64(off)+16 > int64(len(m.mapping.Data)) {
+		return nil, 0, nil, false
+	}
+	nameLen := m.load32(off+8) & 0x00ffffff
+	if nameLen == 0 || int64(off)+16+int64(nameLen) > int64(len(m.mapping.Data)) {
+		return nil, 0, nil, false
+	}
+	name = m.mapping.Data[off+16 : off+16+nameLen]
+	next = m.load32(off + 12)
+	v = (*atomic.Uint64)(unsafe.Pointer(&m.mapping.Data[off]))
+	return name, next, v, true
+}
+
+// writeEntryAt writes a new counter record at the given offset.
+//
+// See the documentation for [mappedFile] for a description of the counter record layout.
+//
+// writeEntryAt only returns false in the presence of some form of corruption:
+// an offset outside the bounds of the record region in the mapped file.
+func (m *mappedFile) writeEntryAt(off uint32, name string) (next *atomic.Uint32, v *atomic.Uint64, ok bool) {
+	// TODO(rfindley): shouldn't this first condition be off < m.hdrLen+hashOff+4*numHash?
+	if off < m.hdrLen+hashOff || int64(off)+16+int64(len(name)) > int64(len(m.mapping.Data)) {
+		return nil, nil, false
+	}
+	copy(m.mapping.Data[off+16:], name)
+	atomic.StoreUint32((*uint32)(unsafe.Pointer(&m.mapping.Data[off+8])), uint32(len(name))|0xff000000)
+	next = (*atomic.Uint32)(unsafe.Pointer(&m.mapping.Data[off+12]))
+	v = (*atomic.Uint64)(unsafe.Pointer(&m.mapping.Data[off]))
+	return next, v, true
+}
+
+// lookup searches the mapped file for a counter record with the given name, returning:
+//   - v: the mapped counter value
+//   - headOff: the offset of the head pointer (see [mappedFile])
+//   - head: the value of the head pointer
+//   - ok: whether lookup succeeded
+func (m *mappedFile) lookup(name string) (v *atomic.Uint64, headOff, head uint32, ok bool) {
+	h := hash(name)
+	headOff = m.hdrLen + hashOff + h*4
+	head = m.load32(headOff)
+	off := head
+	for off != 0 {
+		ename, next, v, ok := m.entryAt(off)
+		if !ok {
+			return nil, 0, 0, false
+		}
+		if string(ename) == name {
+			return v, headOff, head, true
+		}
+		off = next
+	}
+	return nil, headOff, head, true
+}
+
+// newCounter allocates and writes a new counter record with the given name.
+//
+// If name is already recorded in the file, newCounter returns the existing counter.
+func (m *mappedFile) newCounter(name string) (v *atomic.Uint64, m1 *mappedFile, err error) {
+	if len(name) > maxNameLen {
+		return nil, nil, fmt.Errorf("counter name too long")
+	}
+	orig := m
+	defer func() {
+		if m != orig {
+			if err != nil {
+				m.close()
+			} else {
+				m1 = m
+			}
+		}
+	}()
+
+	v, headOff, head, ok := m.lookup(name)
+	for tries := 0; !ok; tries++ {
+		if tries >= 10 {
+			debugFatalf("corrupt: failed to remap after 10 tries")
+			return nil, nil, errCorrupt
+		}
+		// Lookup found an invalid pointer,
+		// perhaps because the file has grown larger than the mapping.
+		limit := m.load32(m.hdrLen + limitOff)
+		if limit, datalen := int64(limit), int64(len(m.mapping.Data)); limit <= datalen {
+			// Mapping doesn't need to grow, so lookup found actual corruption,
+			// in the form of an entry pointer that exceeds the recorded allocation
+			// limit. This should never happen, unless the actual file contents are
+			// corrupt.
+			debugFatalf("corrupt: limit %d is within mapping length %d", limit, datalen)
+			return nil, nil, errCorrupt
+		}
+		// That the recorded limit is greater than the mapped data indicates that
+		// an external process has extended the file. Re-map to pick up this extension.
+		newM, err := openMapped(m.f.Name(), m.meta)
+		if err != nil {
+			return nil, nil, err
+		}
+		if limit, datalen := int64(limit), int64(len(newM.mapping.Data)); limit > datalen {
+			// We've re-mapped, yet limit still exceeds the data length. This
+			// indicates that the underlying file was somehow truncated, or the
+			// recorded limit is corrupt.
+			debugFatalf("corrupt: limit %d exceeds file size %d", limit, datalen)
+			return nil, nil, errCorrupt
+		}
+		// If m != orig, this is at least the second time around the loop
+		// trying to open the mapping. Close the previous attempt.
+		if m != orig {
+			m.close()
+		}
+		m = newM
+		v, headOff, head, ok = m.lookup(name)
+	}
+	if v != nil {
+		return v, nil, nil
+	}
+
+	// Reserve space for new record.
+	// We are competing against other programs using the same file,
+	// so we use a compare-and-swap on the allocation limit in the header.
+	var start, end uint32
+	for {
+		// Determine where record should end, and grow file if needed.
+		limit := m.load32(m.hdrLen + limitOff)
+		start, end = m.place(limit, name)
+		debugPrintf("place %s at %#x-%#x\n", name, start, end)
+		if int64(end) > int64(len(m.mapping.Data)) {
+			newM, err := m.extend(end)
+			if err != nil {
+				return nil, nil, err
+			}
+			if m != orig {
+				m.close()
+			}
+			m = newM
+			continue
+		}
+
+		// Attempt to reserve that space for our record.
+		if m.cas32(m.hdrLen+limitOff, limit, end) {
+			break
+		}
+	}
+
+	// Write record.
+	next, v, ok := m.writeEntryAt(start, name)
+	if !ok {
+		debugFatalf("corrupt: failed to write entry: %#x+%d vs %#x\n", start, len(name), len(m.mapping.Data))
+		return nil, nil, errCorrupt // more likely our math is wrong
+	}
+
+	// Link record into hash chain, making sure not to introduce a duplicate.
+	// We know name does not appear in the chain starting at head.
+	for {
+		next.Store(head)
+		if m.cas32(headOff, head, start) {
+			return v, nil, nil
+		}
+
+		// Check new elements in chain for duplicates.
+		old := head
+		head = m.load32(headOff)
+		for off := head; off != old; {
+			ename, enext, v, ok := m.entryAt(off)
+			if !ok {
+				return nil, nil, errCorrupt
+			}
+			if string(ename) == name {
+				next.Store(^uint32(0)) // mark ours as dead
+				return v, nil, nil
+			}
+			off = enext
+		}
+	}
+}
+
+func (m *mappedFile) extend(end uint32) (*mappedFile, error) {
+	end = round(end, pageSize)
+	info, err := m.f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	if info.Size() < int64(end) {
+		// Note: multiple processes could be calling extend at the same time,
+		// but this write only writes the last 4 bytes of the page.
+		// The last 4 bytes of the page are reserved for this purpose and hold no data.
+		// (In m.place, if a new record would extend to the very end of the page,
+		// it is placed in the next page instead.)
+		// So it is fine if multiple processes extend at the same time.
+		if _, err := m.f.WriteAt(m.zero[:], int64(end)-int64(len(m.zero))); err != nil {
+			return nil, err
+		}
+	}
+	newM, err := openMapped(m.f.Name(), m.meta)
+	if err != nil {
+		return nil, err
+	}
+	if int64(len(newM.mapping.Data)) < int64(end) {
+		// File system or logic bug: new file is somehow not extended.
+		// See go.dev/issue/68311, where this appears to have been happening.
+		newM.close()
+		return nil, errCorrupt
+	}
+	return newM, err
+}
+
+// round returns x rounded up to the next multiple of unit,
+// which must be a power of two.
+func round[T int | uint32](x T, unit T) T {
+	return (x + unit - 1) &^ (unit - 1)
+}

vendor/golang.org/x/telemetry/internal/counter/parse.go

@@ -0,0 +1,82 @@
+// Copyright 2023 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 counter
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"unsafe"
+
+	"golang.org/x/telemetry/internal/mmap"
+)
+
+type File struct {
+	Meta  map[string]string
+	Count map[string]uint64
+}
+
+func Parse(filename string, data []byte) (*File, error) {
+	if !bytes.HasPrefix(data, []byte(hdrPrefix)) || len(data) < pageSize {
+		if len(data) < pageSize {
+			return nil, fmt.Errorf("%s: file too short (%d<%d)", filename, len(data), pageSize)
+		}
+		return nil, fmt.Errorf("%s: wrong hdr (not %q)", filename, hdrPrefix)
+	}
+	corrupt := func() (*File, error) {
+		// TODO(rfindley): return a useful error message.
+		return nil, fmt.Errorf("%s: corrupt counter file", filename)
+	}
+
+	f := &File{
+		Meta:  make(map[string]string),
+		Count: make(map[string]uint64),
+	}
+	np := round(len(hdrPrefix), 4)
+	hdrLen := *(*uint32)(unsafe.Pointer(&data[np]))
+	if hdrLen > pageSize {
+		return corrupt()
+	}
+	meta := data[np+4 : hdrLen]
+	if i := bytes.IndexByte(meta, 0); i >= 0 {
+		meta = meta[:i]
+	}
+	m := &mappedFile{
+		meta:    string(meta),
+		hdrLen:  hdrLen,
+		mapping: &mmap.Data{Data: data},
+	}
+
+	lines := strings.Split(m.meta, "\n")
+	for _, line := range lines {
+		if line == "" {
+			continue
+		}
+		k, v, ok := strings.Cut(line, ": ")
+		if !ok {
+			return corrupt()
+		}
+		f.Meta[k] = v
+	}
+
+	for i := uint32(0); i < numHash; i++ {
+		headOff := hdrLen + hashOff + i*4
+		head := m.load32(headOff)
+		off := head
+		for off != 0 {
+			ename, next, v, ok := m.entryAt(off)
+			if !ok {
+				return corrupt()
+			}
+			if _, ok := f.Count[string(ename)]; ok {
+				return corrupt()
+			}
+			ctrName := DecodeStack(string(ename))
+			f.Count[ctrName] = v.Load()
+			off = next
+		}
+	}
+	return f, nil
+}

vendor/golang.org/x/telemetry/internal/counter/stackcounter.go

@@ -0,0 +1,212 @@
+// Copyright 2023 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 counter
+
+import (
+	"fmt"
+	"runtime"
+	"strings"
+	"sync"
+)
+
+// On the disk, and upstream, stack counters look like sets of
+// regular counters with names that include newlines.
+
+// a StackCounter is the in-memory knowledge about a stack counter.
+// StackCounters are more expensive to use than regular Counters,
+// requiring, at a minimum, a call to runtime.Callers.
+type StackCounter struct {
+	name  string
+	depth int
+	file  *file
+
+	mu sync.Mutex
+	// as this is a detail of the implementation, it could be replaced
+	// by a more efficient mechanism
+	stacks []stack
+}
+
+type stack struct {
+	pcs     []uintptr
+	counter *Counter
+}
+
+func NewStack(name string, depth int) *StackCounter {
+	return &StackCounter{name: name, depth: depth, file: &defaultFile}
+}
+
+// Inc increments a stack counter. It computes the caller's stack and
+// looks up the corresponding counter. It then increments that counter,
+// creating it if necessary.
+func (c *StackCounter) Inc() {
+	pcs := make([]uintptr, c.depth)
+	n := runtime.Callers(2, pcs) // caller of Inc
+	pcs = pcs[:n]
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// Existing counter?
+	var ctr *Counter
+	for _, s := range c.stacks {
+		if eq(s.pcs, pcs) {
+			if s.counter != nil {
+				ctr = s.counter
+				break
+			}
+		}
+	}
+
+	if ctr == nil {
+		// Create new counter.
+		ctr = &Counter{
+			name: EncodeStack(pcs, c.name),
+			file: c.file,
+		}
+		c.stacks = append(c.stacks, stack{pcs: pcs, counter: ctr})
+	}
+
+	ctr.Inc()
+}
+
+// EncodeStack returns the name of the counter to
+// use for the given stack of program counters.
+// The name encodes the stack.
+func EncodeStack(pcs []uintptr, prefix string) string {
+	var locs []string
+	lastImport := ""
+	frs := runtime.CallersFrames(pcs)
+	for {
+		fr, more := frs.Next()
+		// TODO(adonovan): this CutLast(".") operation isn't
+		// appropriate for generic function symbols.
+		path, fname := cutLastDot(fr.Function)
+		if path == lastImport {
+			path = `"` // (a ditto mark)
+		} else {
+			lastImport = path
+		}
+		var loc string
+		if fr.Func != nil {
+			// Use function-relative line numbering.
+			// f:+2 means two lines into function f.
+			// f:-1 should never happen, but be conservative.
+			//
+			// An inlined call is replaced by a NOP instruction
+			// with the correct pclntab information.
+			_, entryLine := fr.Func.FileLine(fr.Entry)
+			loc = fmt.Sprintf("%s.%s:%+d,+0x%x", path, fname, fr.Line-entryLine, fr.PC-fr.Entry)
+		} else {
+			// The function is non-Go code or is fully inlined:
+			// use absolute line number within enclosing file.
+			//
+			// For inlined calls, the PC and Entry values
+			// both refer to the enclosing combined function.
+			// For example, both these PCs are relative to "caller":
+			//
+			//   callee:=1,+0x12        ('=' means inlined)
+			//   caller:+2,+0x34
+			loc = fmt.Sprintf("%s.%s:=%d,+0x%x", path, fname, fr.Line, fr.PC-fr.Entry)
+		}
+		locs = append(locs, loc)
+		if !more {
+			break
+		}
+	}
+
+	name := prefix + "\n" + strings.Join(locs, "\n")
+	if len(name) > maxNameLen {
+		const bad = "\ntruncated\n"
+		name = name[:maxNameLen-len(bad)] + bad
+	}
+	return name
+}
+
+// DecodeStack expands the (compressed) stack encoded in the counter name.
+func DecodeStack(ename string) string {
+	if !strings.Contains(ename, "\n") {
+		return ename // not a stack counter
+	}
+	lines := strings.Split(ename, "\n")
+	var lastPath string // empty or ends with .
+	for i, line := range lines {
+		path, rest := cutLastDot(line)
+		if len(path) == 0 {
+			continue // unchanged
+		}
+		if len(path) == 1 && path[0] == '"' {
+			lines[i] = lastPath + rest
+		} else {
+			lastPath = path + "."
+			// line unchanged
+		}
+	}
+	return strings.Join(lines, "\n") // trailing \n?
+}
+
+// input is <import path>.<function name>
+// output is (import path, function name)
+func cutLastDot(x string) (before, after string) {
+	i := strings.LastIndex(x, ".")
+	if i < 0 {
+		return "", x
+	}
+	return x[:i], x[i+1:]
+}
+
+// Names reports all the counter names associated with a StackCounter.
+func (c *StackCounter) Names() []string {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	names := make([]string, len(c.stacks))
+	for i, s := range c.stacks {
+		names[i] = s.counter.Name()
+	}
+	return names
+}
+
+// Counters returns the known Counters for a StackCounter.
+// There may be more in the count file.
+func (c *StackCounter) Counters() []*Counter {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	counters := make([]*Counter, len(c.stacks))
+	for i, s := range c.stacks {
+		counters[i] = s.counter
+	}
+	return counters
+}
+
+func eq(a, b []uintptr) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// ReadStack reads the given stack counter.
+// This is the implementation of
+// golang.org/x/telemetry/counter/countertest.ReadStackCounter.
+func ReadStack(c *StackCounter) (map[string]uint64, error) {
+	ret := map[string]uint64{}
+	for _, ctr := range c.Counters() {
+		v, err := Read(ctr)
+		if err != nil {
+			return nil, err
+		}
+		ret[DecodeStack(ctr.Name())] = v
+	}
+	return ret, nil
+}
+
+// IsStackCounter reports whether the counter name is for a stack counter.
+func IsStackCounter(name string) bool {
+	return strings.Contains(name, "\n")
+}

vendor/golang.org/x/telemetry/internal/crashmonitor/monitor.go

@@ -0,0 +1,328 @@
+// Copyright 2024 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 crashmonitor
+
+// This file defines a monitor that reports arbitrary Go runtime
+// crashes to telemetry.
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"reflect"
+	"runtime/debug"
+	"strconv"
+	"strings"
+
+	"golang.org/x/telemetry/internal/counter"
+)
+
+// Parent sets up the parent side of the crashmonitor. It requires
+// exclusive use of a writable pipe connected to the child process's stdin.
+func Parent(pipe *os.File) {
+	writeSentinel(pipe)
+	// Ensure that we get pc=0x%x values in the traceback.
+	debug.SetTraceback("system")
+	debug.SetCrashOutput(pipe, debug.CrashOptions{}) // ignore error
+}
+
+// Child runs the part of the crashmonitor that runs in the child process.
+// It expects its stdin to be connected via a pipe to the parent which has
+// run Parent.
+func Child() {
+	// Wait for parent process's dying gasp.
+	// If the parent dies for any reason this read will return.
+	data, err := io.ReadAll(os.Stdin)
+	if err != nil {
+		log.Fatalf("failed to read from input pipe: %v", err)
+	}
+
+	// If the only line is the sentinel, it wasn't a crash.
+	if bytes.Count(data, []byte("\n")) < 2 {
+		childExitHook()
+		os.Exit(0) // parent exited without crash report
+	}
+
+	log.Printf("parent reported crash:\n%s", data)
+
+	// Parse the stack out of the crash report
+	// and record a telemetry count for it.
+	name, err := telemetryCounterName(data)
+	if err != nil {
+		// Keep count of how often this happens
+		// so that we can investigate if necessary.
+		incrementCounter("crash/malformed")
+
+		// Something went wrong.
+		// Save the crash securely in the file system.
+		f, err := os.CreateTemp(os.TempDir(), "*.crash")
+		if err != nil {
+			log.Fatal(err)
+		}
+		if _, err := f.Write(data); err != nil {
+			log.Fatal(err)
+		}
+		if err := f.Close(); err != nil {
+			log.Fatal(err)
+		}
+		log.Printf("failed to report crash to telemetry: %v", err)
+		log.Fatalf("crash report saved at %s", f.Name())
+	}
+
+	incrementCounter(name)
+
+	childExitHook()
+	log.Fatalf("telemetry crash recorded")
+}
+
+// (stubbed by test)
+var (
+	incrementCounter = func(name string) { counter.New(name).Inc() }
+	childExitHook    = func() {}
+)
+
+// The sentinel function returns its address. The difference between
+// this value as observed by calls in two different processes of the
+// same executable tells us the relative offset of their text segments.
+//
+// It would be nice if SetCrashOutput took care of this as it's fiddly
+// and likely to confuse every user at first.
+func sentinel() uint64 {
+	return uint64(reflect.ValueOf(sentinel).Pointer())
+}
+
+func writeSentinel(out io.Writer) {
+	fmt.Fprintf(out, "sentinel %x\n", sentinel())
+}
+
+// telemetryCounterName parses a crash report produced by the Go
+// runtime, extracts the stack of the first runnable goroutine,
+// converts each line into telemetry form ("symbol:relative-line"),
+// and returns this as the name of a counter.
+func telemetryCounterName(crash []byte) (string, error) {
+	pcs, err := parseStackPCs(string(crash))
+	if err != nil {
+		return "", err
+	}
+
+	// Limit the number of frames we request.
+	pcs = pcs[:min(len(pcs), 16)]
+
+	if len(pcs) == 0 {
+		// This can occur if all goroutines are idle, as when
+		// caught in a deadlock, or killed by an async signal
+		// while blocked.
+		//
+		// TODO(adonovan): consider how to report such
+		// situations. Reporting a goroutine in [sleep] or
+		// [select] state could be quite confusing without
+		// further information about the nature of the crash,
+		// as the problem is not local to the code location.
+		//
+		// For now, we keep count of this situation so that we
+		// can access whether it needs a more involved solution.
+		return "crash/no-running-goroutine", nil
+	}
+
+	// This string appears at the start of all
+	// crashmonitor-generated counter names.
+	//
+	// It is tempting to expose this as a parameter of Start, but
+	// it is not without risk. What value should most programs
+	// provide? There's no point giving the name of the executable
+	// as this is already recorded by telemetry. What if the
+	// application runs in multiple modes? Then it might be useful
+	// to record the mode. The problem is that an application with
+	// multiple modes probably doesn't know its mode by line 1 of
+	// main.main: it might require flag or argument parsing, or
+	// even validation of an environment variable, and we really
+	// want to steer users aware from any logic before Start. The
+	// flags and arguments will be wrong in the child process, and
+	// every extra conditional branch creates a risk that the
+	// recursively executed child program will behave not like the
+	// monitor but like the application. If the child process
+	// exits before calling Start, then the parent application
+	// will not have a monitor, and its crash reports will be
+	// discarded (written in to a pipe that is never read).
+	//
+	// So for now, we use this constant string.
+	const prefix = "crash/crash"
+	return counter.EncodeStack(pcs, prefix), nil
+}
+
+// parseStackPCs parses the parent process's program counters for the
+// first running goroutine out of a GOTRACEBACK=system traceback,
+// adjusting them so that they are valid for the child process's text
+// segment.
+//
+// This function returns only program counter values, ensuring that
+// there is no possibility of strings from the crash report (which may
+// contain PII) leaking into the telemetry system.
+func parseStackPCs(crash string) ([]uintptr, error) {
+	// getSymbol parses the symbol name out of a line of the form:
+	// SYMBOL(ARGS)
+	//
+	// Note: SYMBOL may contain parens "pkg.(*T).method". However, type
+	// parameters are always replaced with ..., so they cannot introduce
+	// more parens. e.g., "pkg.(*T[...]).method".
+	//
+	// ARGS can contain parens. We want the first paren that is not
+	// immediately preceded by a ".".
+	//
+	// TODO(prattmic): This is mildly complicated and is only used to find
+	// runtime.sigpanic, so perhaps simplify this by checking explicitly
+	// for sigpanic.
+	getSymbol := func(line string) (string, error) {
+		var prev rune
+		for i, c := range line {
+			if line[i] != '(' {
+				prev = c
+				continue
+			}
+			if prev == '.' {
+				prev = c
+				continue
+			}
+			return line[:i], nil
+		}
+		return "", fmt.Errorf("no symbol for stack frame: %s", line)
+	}
+
+	// getPC parses the PC out of a line of the form:
+	//     \tFILE:LINE +0xRELPC sp=... fp=... pc=...
+	getPC := func(line string) (uint64, error) {
+		_, pcstr, ok := strings.Cut(line, " pc=") // e.g. pc=0x%x
+		if !ok {
+			return 0, fmt.Errorf("no pc= for stack frame: %s", line)
+		}
+		return strconv.ParseUint(pcstr, 0, 64) // 0 => allow 0x prefix
+	}
+
+	var (
+		pcs            []uintptr
+		parentSentinel uint64
+		childSentinel  = sentinel()
+		on             = false // are we in the first running goroutine?
+		lines          = strings.Split(crash, "\n")
+		symLine        = true // within a goroutine, every other line is a symbol or file/line/pc location, starting with symbol.
+		currSymbol     string
+		prevSymbol     string // symbol of the most recent previous frame with a PC.
+	)
+	for i := 0; i < len(lines); i++ {
+		line := lines[i]
+
+		// Read sentinel value.
+		if parentSentinel == 0 && strings.HasPrefix(line, "sentinel ") {
+			_, err := fmt.Sscanf(line, "sentinel %x", &parentSentinel)
+			if err != nil {
+				return nil, fmt.Errorf("can't read sentinel line")
+			}
+			continue
+		}
+
+		// Search for "goroutine GID [STATUS]"
+		if !on {
+			if strings.HasPrefix(line, "goroutine ") &&
+				strings.Contains(line, " [running]:") {
+				on = true
+
+				if parentSentinel == 0 {
+					return nil, fmt.Errorf("no sentinel value in crash report")
+				}
+			}
+			continue
+		}
+
+		// A blank line marks end of a goroutine stack.
+		if line == "" {
+			break
+		}
+
+		// Skip the final "created by SYMBOL in goroutine GID" part.
+		if strings.HasPrefix(line, "created by ") {
+			break
+		}
+
+		// Expect a pair of lines:
+		//   SYMBOL(ARGS)
+		//   \tFILE:LINE +0xRELPC sp=0x%x fp=0x%x pc=0x%x
+		// Note: SYMBOL may contain parens "pkg.(*T).method"
+		// The RELPC is sometimes missing.
+
+		if symLine {
+			var err error
+			currSymbol, err = getSymbol(line)
+			if err != nil {
+				return nil, fmt.Errorf("error extracting symbol: %v", err)
+			}
+
+			symLine = false // Next line is FILE:LINE.
+		} else {
+			// Parse the PC, and correct for the parent and child's
+			// different mappings of the text section.
+			pc, err := getPC(line)
+			if err != nil {
+				// Inlined frame, perhaps; skip it.
+
+				// Done with this frame. Next line is a new frame.
+				//
+				// Don't update prevSymbol; we only want to
+				// track frames with a PC.
+				currSymbol = ""
+				symLine = true
+				continue
+			}
+
+			pc = pc - parentSentinel + childSentinel
+
+			// If the previous frame was sigpanic, then this frame
+			// was a trap (e.g., SIGSEGV).
+			//
+			// Typically all middle frames are calls, and report
+			// the "return PC". That is, the instruction following
+			// the CALL where the callee will eventually return to.
+			//
+			// runtime.CallersFrames is aware of this property and
+			// will decrement each PC by 1 to "back up" to the
+			// location of the CALL, which is the actual line
+			// number the user expects.
+			//
+			// This does not work for traps, as a trap is not a
+			// call, so the reported PC is not the return PC, but
+			// the actual PC of the trap.
+			//
+			// runtime.Callers is aware of this and will
+			// intentionally increment trap PCs in order to correct
+			// for the decrement performed by
+			// runtime.CallersFrames. See runtime.tracebackPCs and
+			// runtume.(*unwinder).symPC.
+			//
+			// We must emulate the same behavior, otherwise we will
+			// report the location of the instruction immediately
+			// prior to the trap, which may be on a different line,
+			// or even a different inlined functions.
+			//
+			// TODO(prattmic): The runtime applies the same trap
+			// behavior for other "injected calls", see injectCall
+			// in runtime.(*unwinder).next. Do we want to handle
+			// those as well? I don't believe we'd ever see
+			// runtime.asyncPreempt or runtime.debugCallV2 in a
+			// typical crash.
+			if prevSymbol == "runtime.sigpanic" {
+				pc++
+			}
+
+			pcs = append(pcs, uintptr(pc))
+
+			// Done with this frame. Next line is a new frame.
+			prevSymbol = currSymbol
+			currSymbol = ""
+			symLine = true
+		}
+	}
+	return pcs, nil
+}

vendor/golang.org/x/telemetry/internal/mmap/mmap.go

@@ -0,0 +1,36 @@
+// Copyright 2011 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.
+
+// This package is a lightly modified version of the mmap code
+// in github.com/google/codesearch/index.
+
+// The mmap package provides an abstraction for memory mapping files
+// on different platforms.
+package mmap
+
+import (
+	"os"
+)
+
+// The backing file is never closed, so Data
+// remains valid for the lifetime of the process.
+type Data struct {
+	// TODO(pjw): might be better to define versions of Data
+	// for the 3 specializations
+	f    *os.File
+	Data []byte
+	// Some windows magic
+	Windows interface{}
+}
+
+// Mmap maps the given file into memory.
+// When remapping a file, pass the most recently returned Data.
+func Mmap(f *os.File) (*Data, error) {
+	return mmapFile(f)
+}
+
+// Munmap unmaps the given file from memory.
+func Munmap(d *Data) error {
+	return munmapFile(d)
+}

vendor/golang.org/x/telemetry/internal/mmap/mmap_other.go

@@ -0,0 +1,25 @@
+// Copyright 2022 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.
+
+//go:build (js && wasm) || wasip1 || plan9
+
+package mmap
+
+import (
+	"io"
+	"os"
+)
+
+// mmapFile on other systems doesn't mmap the file. It just reads everything.
+func mmapFile(f *os.File) (*Data, error) {
+	b, err := io.ReadAll(f)
+	if err != nil {
+		return nil, err
+	}
+	return &Data{f, b, nil}, nil
+}
+
+func munmapFile(_ *Data) error {
+	return nil
+}

vendor/golang.org/x/telemetry/internal/mmap/mmap_unix.go

@@ -0,0 +1,47 @@
+// Copyright 2011 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.
+
+//go:build unix
+
+package mmap
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"syscall"
+)
+
+func mmapFile(f *os.File) (*Data, error) {
+	st, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	size := st.Size()
+	pagesize := int64(os.Getpagesize())
+	if int64(int(size+(pagesize-1))) != size+(pagesize-1) {
+		return nil, fmt.Errorf("%s: too large for mmap", f.Name())
+	}
+	n := int(size)
+	if n == 0 {
+		return &Data{f, nil, nil}, nil
+	}
+	mmapLength := int(((size + pagesize - 1) / pagesize) * pagesize) // round up to page size
+	data, err := syscall.Mmap(int(f.Fd()), 0, mmapLength, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
+	if err != nil {
+		return nil, &fs.PathError{Op: "mmap", Path: f.Name(), Err: err}
+	}
+	return &Data{f, data[:n], nil}, nil
+}
+
+func munmapFile(d *Data) error {
+	if len(d.Data) == 0 {
+		return nil
+	}
+	err := syscall.Munmap(d.Data)
+	if err != nil {
+		return &fs.PathError{Op: "munmap", Path: d.f.Name(), Err: err}
+	}
+	return nil
+}

vendor/golang.org/x/telemetry/internal/mmap/mmap_windows.go

@@ -0,0 +1,52 @@
+// Copyright 2011 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 mmap
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+func mmapFile(f *os.File) (*Data, error) {
+	st, err := f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	size := st.Size()
+	if size == 0 {
+		return &Data{f, nil, nil}, nil
+	}
+	// set the min and max sizes to zero to map the whole file, as described in
+	// https://learn.microsoft.com/en-us/windows/win32/memory/creating-a-file-mapping-object#file-mapping-size
+	h, err := windows.CreateFileMapping(windows.Handle(f.Fd()), nil, syscall.PAGE_READWRITE, 0, 0, nil)
+	if err != nil {
+		return nil, fmt.Errorf("CreateFileMapping %s: %w", f.Name(), err)
+	}
+	// the mapping extends from zero to the end of the file mapping
+	// https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-mapviewoffile
+	addr, err := windows.MapViewOfFile(h, syscall.FILE_MAP_READ|syscall.FILE_MAP_WRITE, 0, 0, 0)
+	if err != nil {
+		return nil, fmt.Errorf("MapViewOfFile %s: %w", f.Name(), err)
+	}
+	// Note: previously, we called windows.VirtualQuery here to get the exact
+	// size of the memory mapped region, but VirtualQuery reported sizes smaller
+	// than the actual file size (hypothesis: VirtualQuery only reports pages in
+	// a certain state, and newly written pages may not be counted).
+	return &Data{f, unsafe.Slice((*byte)(unsafe.Pointer(addr)), size), h}, nil
+}
+
+func munmapFile(d *Data) error {
+	err := windows.UnmapViewOfFile(uintptr(unsafe.Pointer(&d.Data[0])))
+	x, ok := d.Windows.(windows.Handle)
+	if ok {
+		windows.CloseHandle(x)
+	}
+	d.f.Close()
+	return err
+}

vendor/golang.org/x/telemetry/internal/telemetry/dateonly.go

@@ -0,0 +1,9 @@
+// Copyright 2024 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 telemetry
+
+// TODO(rfindley): replace uses of DateOnly with time.DateOnly once we no
+// longer support building gopls with go 1.19.
+const DateOnly = "2006-01-02"

vendor/golang.org/x/telemetry/internal/telemetry/dir.go

@@ -0,0 +1,163 @@
+// Copyright 2023 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 telemetry manages the telemetry mode file.
+package telemetry
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
+)
+
+// Default is the default directory containing Go telemetry configuration and
+// data.
+//
+// If Default is uninitialized, Default.Mode will be "off". As a consequence,
+// no data should be written to the directory, and so the path values of
+// LocalDir, UploadDir, etc. must not matter.
+//
+// Default is a global for convenience and testing, but should not be mutated
+// outside of tests.
+//
+// TODO(rfindley): it would be nice to completely eliminate this global state,
+// or at least push it in the golang.org/x/telemetry package
+var Default Dir
+
+// A Dir holds paths to telemetry data inside a directory.
+type Dir struct {
+	dir, local, upload, debug, modefile string
+}
+
+// NewDir creates a new Dir encapsulating paths in the given dir.
+//
+// NewDir does not create any new directories or files--it merely encapsulates
+// the telemetry directory layout.
+func NewDir(dir string) Dir {
+	return Dir{
+		dir:      dir,
+		local:    filepath.Join(dir, "local"),
+		upload:   filepath.Join(dir, "upload"),
+		debug:    filepath.Join(dir, "debug"),
+		modefile: filepath.Join(dir, "mode"),
+	}
+}
+
+func init() {
+	cfgDir, err := os.UserConfigDir()
+	if err != nil {
+		return
+	}
+	Default = NewDir(filepath.Join(cfgDir, "go", "telemetry"))
+}
+
+func (d Dir) Dir() string {
+	return d.dir
+}
+
+func (d Dir) LocalDir() string {
+	return d.local
+}
+
+func (d Dir) UploadDir() string {
+	return d.upload
+}
+
+func (d Dir) DebugDir() string {
+	return d.debug
+}
+
+func (d Dir) ModeFile() string {
+	return d.modefile
+}
+
+// SetMode updates the telemetry mode with the given mode.
+// Acceptable values for mode are "on", "off", or "local".
+//
+// SetMode always writes the mode file, and explicitly records the date at
+// which the modefile was updated. This means that calling SetMode with "on"
+// effectively resets the timeout before the next telemetry report is uploaded.
+func (d Dir) SetMode(mode string) error {
+	return d.SetModeAsOf(mode, time.Now())
+}
+
+// SetModeAsOf is like SetMode, but accepts an explicit time to use to
+// back-date the mode state. This exists only for testing purposes.
+func (d Dir) SetModeAsOf(mode string, asofTime time.Time) error {
+	mode = strings.TrimSpace(mode)
+	switch mode {
+	case "on", "off", "local":
+	default:
+		return fmt.Errorf("invalid telemetry mode: %q", mode)
+	}
+	if d.modefile == "" {
+		return fmt.Errorf("cannot determine telemetry mode file name")
+	}
+	// TODO(rfindley): why is this not 777, consistent with the use of 666 below?
+	if err := os.MkdirAll(filepath.Dir(d.modefile), 0755); err != nil {
+		return fmt.Errorf("cannot create a telemetry mode file: %w", err)
+	}
+
+	asof := asofTime.UTC().Format(DateOnly)
+	// Defensively guarantee that we can parse the asof time.
+	if _, err := time.Parse(DateOnly, asof); err != nil {
+		return fmt.Errorf("internal error: invalid mode date %q: %v", asof, err)
+	}
+
+	data := []byte(mode + " " + asof)
+	return os.WriteFile(d.modefile, data, 0666)
+}
+
+// Mode returns the current telemetry mode, as well as the time that the mode
+// was effective.
+//
+// If there is no effective time, the second result is the zero time.
+//
+// If Mode is "off", no data should be written to the telemetry directory, and
+// the other paths values referenced by Dir should be considered undefined.
+// This accounts for the case where initializing [Default] fails, and therefore
+// local telemetry paths are unknown.
+func (d Dir) Mode() (string, time.Time) {
+	if d.modefile == "" {
+		return "off", time.Time{} // it's likely LocalDir/UploadDir are empty too. Turn off telemetry.
+	}
+	data, err := os.ReadFile(d.modefile)
+	if err != nil {
+		return "local", time.Time{} // default
+	}
+	mode := string(data)
+	mode = strings.TrimSpace(mode)
+
+	// Forward compatibility for https://go.dev/issue/63142#issuecomment-1734025130
+	//
+	// If the modefile contains a date, return it.
+	if idx := strings.Index(mode, " "); idx >= 0 {
+		d, err := time.Parse(DateOnly, mode[idx+1:])
+		if err != nil {
+			d = time.Time{}
+		}
+		return mode[:idx], d
+	}
+
+	return mode, time.Time{}
+}
+
+// DisabledOnPlatform indicates whether telemetry is disabled
+// due to bugs in the current platform.
+//
+// TODO(rfindley): move to a more appropriate file.
+const DisabledOnPlatform = false ||
+	// The following platforms could potentially be supported in the future:
+	runtime.GOOS == "openbsd" || // #60614
+	runtime.GOOS == "solaris" || // #60968 #60970
+	runtime.GOOS == "android" || // #60967
+	runtime.GOOS == "illumos" || // #65544
+	// These platforms fundamentally can't be supported:
+	runtime.GOOS == "js" || // #60971
+	runtime.GOOS == "wasip1" || // #60971
+	runtime.GOOS == "plan9" || // https://github.com/golang/go/issues/57540#issuecomment-1470766639
+	runtime.GOARCH == "mips" || runtime.GOARCH == "mipsle" // mips lacks cross-process 64-bit atomics

vendor/golang.org/x/telemetry/internal/telemetry/proginfo.go

@@ -0,0 +1,57 @@
+// Copyright 2024 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 telemetry
+
+import (
+	"go/version"
+	"os"
+	"path/filepath"
+	"runtime/debug"
+	"strings"
+)
+
+// IsToolchainProgram reports whether a program with the given path is a Go
+// toolchain program.
+func IsToolchainProgram(progPath string) bool {
+	return strings.HasPrefix(progPath, "cmd/")
+}
+
+// ProgramInfo extracts the go version, program package path, and program
+// version to use for counter files.
+//
+// For programs in the Go toolchain, the program version will be the same as
+// the Go version, and will typically be of the form "go1.2.3", not a semantic
+// version of the form "v1.2.3". Go versions may also include spaces and
+// special characters.
+func ProgramInfo(info *debug.BuildInfo) (goVers, progPath, progVers string) {
+	goVers = info.GoVersion
+	if strings.Contains(goVers, "devel") || strings.Contains(goVers, "-") || !version.IsValid(goVers) {
+		goVers = "devel"
+	}
+
+	progPath = info.Path
+	if progPath == "" {
+		progPath = strings.TrimSuffix(filepath.Base(os.Args[0]), ".exe")
+	}
+
+	// Main module version information is not populated for the cmd module, but
+	// we can re-use the Go version here.
+	if IsToolchainProgram(progPath) {
+		progVers = goVers
+	} else {
+		progVers = info.Main.Version
+		if strings.Contains(progVers, "devel") || strings.Count(progVers, "-") > 1 {
+			// Heuristically mark all pseudo-version-like version strings as "devel"
+			// to avoid creating too many counter files.
+			// We should not use regexp that pulls in large dependencies.
+			// Pseudo-versions have at least three parts (https://go.dev/ref/mod#pseudo-versions).
+			// This heuristic still allows use to track prerelease
+			// versions (e.g. gopls@v0.16.0-pre.1, vscgo@v0.42.0-rc.1).
+			progVers = "devel"
+		}
+	}
+
+	return goVers, progPath, progVers
+}

vendor/golang.org/x/telemetry/internal/telemetry/types.go

@@ -0,0 +1,51 @@
+// Copyright 2023 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 telemetry
+
+// Common types and directories used by multiple packages.
+
+// An UploadConfig controls what data is uploaded.
+type UploadConfig struct {
+	GOOS       []string
+	GOARCH     []string
+	GoVersion  []string
+	SampleRate float64
+	Programs   []*ProgramConfig
+}
+
+type ProgramConfig struct {
+	// the counter names may have to be
+	// repeated for each program. (e.g., if the counters are in a package
+	// that is used in more than one program.)
+	Name     string
+	Versions []string        // versions present in a counterconfig
+	Counters []CounterConfig `json:",omitempty"`
+	Stacks   []CounterConfig `json:",omitempty"`
+}
+
+type CounterConfig struct {
+	Name  string  // The "collapsed" counter: <chart>:{<bucket1>,<bucket2>,...}
+	Rate  float64 // If X <= Rate, report this counter
+	Depth int     `json:",omitempty"` // for stack counters
+}
+
+// A Report is the weekly aggregate of counters.
+type Report struct {
+	Week     string  // End day this report covers (YYYY-MM-DD)
+	LastWeek string  // Week field from latest previous report uploaded
+	X        float64 // A random probability used to determine which counters are uploaded
+	Programs []*ProgramReport
+	Config   string // version of UploadConfig used
+}
+
+type ProgramReport struct {
+	Program   string // Package path of the program.
+	Version   string // Program version. Go version if the program is part of the go distribution. Module version, otherwise.
+	GoVersion string // Go version used to build the program.
+	GOOS      string
+	GOARCH    string
+	Counters  map[string]int64
+	Stacks    map[string]int64
+}

vendor/golang.org/x/telemetry/internal/upload/Doc.txt

@@ -0,0 +1,45 @@
+The upload process converts count files into reports, and
+uploads reports. There will be only one report, named YYYY-MM-DD.json,
+for a given day.
+
+First phase. Look at the localdir (os.UserConfigdir()/go/telemetry/local)
+and find all .count and .json files. Find the count files that are no
+longer active by looking at their metadata.
+
+Second phase. Group the inactive count files by their expiry date, and
+for each date generate the local report and the upload report. (The upload
+report only contains the counters in the upload configuration.) The upload
+report is saved in the local directory with a name like YYYY-MM-DD.json, if
+there is no file already existing with that name.
+If the local report is different, it is saved in the local directory
+with a name like local.YYYY-MM-DD.json. The new upload report is
+added to the list of .json files from the first phase. At this point
+the count files are no longer needed and can be deleted.
+
+Third phase. Look at the .json files in the list from the first phase.
+If the name starts with local, skip it. If there is a file with the
+identical name in the upload directory, remove the one in the local directory.
+Otherwise try to upload the one in the local directory,
+If the upload succeeds, move the file to the uploaded directory.
+
+
+There are various error conditions.
+1. Several processes could look at localdir and see work to do.
+1A. They could see different sets of expired count files for some day.
+    This could happen if another process is removing count files. In this
+    case there is already a YYYY-MM-DD.json file either in localdir
+    or updatedir, so the process seeing fewer count files will not generate
+    a report.
+1B. They could see the same count files, and no report in either directory.
+    They will both generate (in memory) reports and check to see if there
+    is a YYYY-MM-DD.json file in either directory. They could both then
+    write two files with the same name, but different X values, but
+    otherwise the same contents. The X values are very close to the front
+    of the file. Assuming reasonable file system semantics one version of
+    the file will be written. To minimize this, just before writing reports
+    the code checks again to see if they exist.
+1C. Once there is an existing well-formed file YYYY-MM-DD.json in localdir
+    eventually the upload will succeed, and the file will be moved to updatedir.
+    It is possible that other processes will not see the file in updatedir and
+    upload it again and also move it to uploaddir. This is harmless as all
+    the uploaded files are identical.

vendor/golang.org/x/telemetry/internal/upload/date.go

@@ -0,0 +1,85 @@
+// Copyright 2023 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 upload
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"time"
+
+	"golang.org/x/telemetry/internal/counter"
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+// time and date handling
+
+var distantPast = 21 * 24 * time.Hour
+
+// reports that are too old (21 days) are not uploaded
+func (u *uploader) tooOld(date string, uploadStartTime time.Time) bool {
+	t, err := time.Parse(telemetry.DateOnly, date)
+	if err != nil {
+		u.logger.Printf("tooOld: %v", err)
+		return false
+	}
+	age := uploadStartTime.Sub(t)
+	return age > distantPast
+}
+
+// counterDateSpan parses the counter file named fname and returns the (begin,
+// end) span recorded in its metadata, or an error if this data could not be
+// extracted.
+func (u *uploader) counterDateSpan(fname string) (begin, end time.Time, _ error) {
+	parsed, err := u.parseCountFile(fname)
+	if err != nil {
+		return time.Time{}, time.Time{}, err
+	}
+	timeBegin, ok := parsed.Meta["TimeBegin"]
+	if !ok {
+		return time.Time{}, time.Time{}, fmt.Errorf("missing counter metadata for TimeBegin")
+	}
+	begin, err = time.Parse(time.RFC3339, timeBegin)
+	if err != nil {
+		return time.Time{}, time.Time{}, fmt.Errorf("failed to parse TimeBegin: %v", err)
+	}
+	timeEnd, ok := parsed.Meta["TimeEnd"]
+	if !ok {
+		return time.Time{}, time.Time{}, fmt.Errorf("missing counter metadata for TimeEnd")
+	}
+	end, err = time.Parse(time.RFC3339, timeEnd)
+	if err != nil {
+		return time.Time{}, time.Time{}, fmt.Errorf("failed to parse TimeEnd: %v", err)
+	}
+	return begin, end, nil
+}
+
+// avoid parsing count files multiple times
+type parsedCache struct {
+	mu sync.Mutex
+	m  map[string]*counter.File
+}
+
+func (u *uploader) parseCountFile(fname string) (*counter.File, error) {
+	u.cache.mu.Lock()
+	defer u.cache.mu.Unlock()
+	if u.cache.m == nil {
+		u.cache.m = make(map[string]*counter.File)
+	}
+	if f, ok := u.cache.m[fname]; ok {
+		return f, nil
+	}
+	buf, err := os.ReadFile(fname)
+	if err != nil {
+		return nil, fmt.Errorf("parse ReadFile: %v for %s", err, fname)
+	}
+	f, err := counter.Parse(fname, buf)
+	if err != nil {
+
+		return nil, fmt.Errorf("parse Parse: %v for %s", err, fname)
+	}
+	u.cache.m[fname] = f
+	return f, nil
+}

vendor/golang.org/x/telemetry/internal/upload/findwork.go

@@ -0,0 +1,102 @@
+// Copyright 2023 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 upload
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// files to handle
+type work struct {
+	// absolute file names
+	countfiles []string // count files to process
+	readyfiles []string // old reports to upload
+	// relative names
+	uploaded map[string]bool // reports that have been uploaded
+}
+
+// find all the files that look like counter files or reports
+// that need to be uploaded. (There may be unexpected leftover files
+// and uploading is supposed to be idempotent.)
+func (u *uploader) findWork() work {
+	localdir, uploaddir := u.dir.LocalDir(), u.dir.UploadDir()
+	var ans work
+	fis, err := os.ReadDir(localdir)
+	if err != nil {
+		u.logger.Printf("Could not find work: failed to read local dir %s: %v", localdir, err)
+		return ans
+	}
+
+	mode, asof := u.dir.Mode()
+	u.logger.Printf("Finding work: mode %s asof %s", mode, asof)
+
+	// count files end in .v1.count
+	// reports end in .json. If they are not to be uploaded they
+	// start with local.
+	for _, fi := range fis {
+		if strings.HasSuffix(fi.Name(), ".v1.count") {
+			fname := filepath.Join(localdir, fi.Name())
+			_, expiry, err := u.counterDateSpan(fname)
+			switch {
+			case err != nil:
+				u.logger.Printf("Error reading expiry for count file %s: %v", fi.Name(), err)
+			case expiry.After(u.startTime):
+				u.logger.Printf("Skipping count file %s: still active", fi.Name())
+			default:
+				u.logger.Printf("Collecting count file %s", fi.Name())
+				ans.countfiles = append(ans.countfiles, fname)
+			}
+		} else if strings.HasPrefix(fi.Name(), "local.") {
+			// skip
+		} else if strings.HasSuffix(fi.Name(), ".json") && mode == "on" {
+			// Collect reports that are ready for upload.
+			reportDate := u.uploadReportDate(fi.Name())
+			if !asof.IsZero() && !reportDate.IsZero() {
+				// If both the mode asof date and the report date are present, do the
+				// right thing...
+				//
+				// (see https://github.com/golang/go/issues/63142#issuecomment-1734025130)
+				if asof.Before(reportDate) {
+					// Note: since this report was created after telemetry was enabled,
+					// we can only assume that the process that created it checked that
+					// the counter data contained therein was all from after the asof
+					// date.
+					//
+					// TODO(rfindley): store the begin date in reports, so that we can
+					// verify this assumption.
+					u.logger.Printf("Uploadable: %s", fi.Name())
+					ans.readyfiles = append(ans.readyfiles, filepath.Join(localdir, fi.Name()))
+				}
+			} else {
+				// ...otherwise fall back on the old behavior of uploading all
+				// unuploaded files.
+				//
+				// TODO(rfindley): invert this logic following more testing. We
+				// should only upload if we know both the asof date and the report
+				// date, and they are acceptable.
+				u.logger.Printf("Uploadable (missing date): %s", fi.Name())
+				ans.readyfiles = append(ans.readyfiles, filepath.Join(localdir, fi.Name()))
+			}
+		}
+	}
+
+	fis, err = os.ReadDir(uploaddir)
+	if err != nil {
+		os.MkdirAll(uploaddir, 0777)
+		return ans
+	}
+	// There should be only one of these per day; maybe sometime
+	// we'll want to clean the directory.
+	ans.uploaded = make(map[string]bool)
+	for _, fi := range fis {
+		if strings.HasSuffix(fi.Name(), ".json") {
+			u.logger.Printf("Already uploaded: %s", fi.Name())
+			ans.uploaded[fi.Name()] = true
+		}
+	}
+	return ans
+}

vendor/golang.org/x/telemetry/internal/upload/reports.go

@@ -0,0 +1,344 @@
+// Copyright 2023 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 upload
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"math"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"golang.org/x/telemetry/internal/config"
+	"golang.org/x/telemetry/internal/counter"
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+// reports generates reports from inactive count files
+func (u *uploader) reports(todo *work) ([]string, error) {
+	if mode, _ := u.dir.Mode(); mode == "off" {
+		return nil, nil // no reports
+	}
+	thisInstant := u.startTime
+	today := thisInstant.Format(telemetry.DateOnly)
+	lastWeek := latestReport(todo.uploaded)
+	if lastWeek >= today { //should never happen
+		lastWeek = ""
+	}
+	u.logger.Printf("Last week: %s, today: %s", lastWeek, today)
+	countFiles := make(map[string][]string) // expiry date string->filenames
+	earliest := make(map[string]time.Time)  // earliest begin time for any counter
+	for _, f := range todo.countfiles {
+		begin, end, err := u.counterDateSpan(f)
+		if err != nil {
+			// This shouldn't happen: we should have already skipped count files that
+			// don't contain valid start or end times.
+			u.logger.Printf("BUG: failed to parse expiry for collected count file: %v", err)
+			continue
+		}
+
+		if end.Before(thisInstant) {
+			expiry := end.Format(dateFormat)
+			countFiles[expiry] = append(countFiles[expiry], f)
+			if earliest[expiry].IsZero() || earliest[expiry].After(begin) {
+				earliest[expiry] = begin
+			}
+		}
+	}
+	for expiry, files := range countFiles {
+		if notNeeded(expiry, *todo) {
+			u.logger.Printf("Files for %s not needed, deleting %v", expiry, files)
+			// The report already exists.
+			// There's another check in createReport.
+			u.deleteFiles(files)
+			continue
+		}
+		fname, err := u.createReport(earliest[expiry], expiry, files, lastWeek)
+		if err != nil {
+			u.logger.Printf("Failed to create report for %s: %v", expiry, err)
+			continue
+		}
+		if fname != "" {
+			u.logger.Printf("Ready to upload: %s", filepath.Base(fname))
+			todo.readyfiles = append(todo.readyfiles, fname)
+		}
+	}
+	return todo.readyfiles, nil
+}
+
+// latestReport returns the YYYY-MM-DD of the last report uploaded
+// or the empty string if there are no reports.
+func latestReport(uploaded map[string]bool) string {
+	var latest string
+	for name := range uploaded {
+		if strings.HasSuffix(name, ".json") {
+			if name > latest {
+				latest = name
+			}
+		}
+	}
+	if latest == "" {
+		return ""
+	}
+	// strip off the .json
+	return latest[:len(latest)-len(".json")]
+}
+
+// notNeeded returns true if the report for date has already been created
+func notNeeded(date string, todo work) bool {
+	if todo.uploaded != nil && todo.uploaded[date+".json"] {
+		return true
+	}
+	// maybe the report is already in todo.readyfiles
+	for _, f := range todo.readyfiles {
+		if strings.Contains(f, date) {
+			return true
+		}
+	}
+	return false
+}
+
+func (u *uploader) deleteFiles(files []string) {
+	for _, f := range files {
+		if err := os.Remove(f); err != nil {
+			// this could be a race condition.
+			// conversely, on Windows, err may be nil and
+			// the file not deleted if anyone has it open.
+			u.logger.Printf("%v failed to remove %s", err, f)
+		}
+	}
+}
+
+// createReport creates local and upload report files by
+// combining all the count files for the expiryDate, and
+// returns the upload report file's path.
+// It may delete the count files once local and upload report
+// files are successfully created.
+func (u *uploader) createReport(start time.Time, expiryDate string, countFiles []string, lastWeek string) (string, error) {
+	uploadOK := true
+	mode, asof := u.dir.Mode()
+	if mode != "on" {
+		u.logger.Printf("No upload config or mode %q is not 'on'", mode)
+		uploadOK = false // no config, nothing to upload
+	}
+	if u.tooOld(expiryDate, u.startTime) {
+		u.logger.Printf("Expiry date %s is too old", expiryDate)
+		uploadOK = false
+	}
+	// If the mode is recorded with an asof date, don't upload if the report
+	// includes any data on or before the asof date.
+	if !asof.IsZero() && !asof.Before(start) {
+		u.logger.Printf("As-of date %s is not before start %s", asof, start)
+		uploadOK = false
+	}
+	// TODO(rfindley): check that all the x.Meta are consistent for GOOS, GOARCH, etc.
+	report := &telemetry.Report{
+		Config:   u.configVersion,
+		X:        computeRandom(), // json encodes all the bits
+		Week:     expiryDate,
+		LastWeek: lastWeek,
+	}
+	if report.X > u.config.SampleRate && u.config.SampleRate > 0 {
+		u.logger.Printf("X: %f > SampleRate:%f, not uploadable", report.X, u.config.SampleRate)
+		uploadOK = false
+	}
+	var succeeded bool
+	for _, f := range countFiles {
+		fok := false
+		x, err := u.parseCountFile(f)
+		if err != nil {
+			u.logger.Printf("Unparseable count file %s: %v", filepath.Base(f), err)
+			continue
+		}
+		prog := findProgReport(x.Meta, report)
+		for k, v := range x.Count {
+			if counter.IsStackCounter(k) {
+				// stack
+				prog.Stacks[k] += int64(v)
+			} else {
+				// counter
+				prog.Counters[k] += int64(v)
+			}
+			succeeded = true
+			fok = true
+		}
+		if !fok {
+			u.logger.Printf("no counters found in %s", f)
+		}
+	}
+	if !succeeded {
+		return "", fmt.Errorf("none of the %d count files for %s contained counters", len(countFiles), expiryDate)
+	}
+	// 1. generate the local report
+	localContents, err := json.MarshalIndent(report, "", " ")
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal report for %s: %v", expiryDate, err)
+	}
+	// check that the report can be read back
+	// TODO(pjw): remove for production?
+	var report2 telemetry.Report
+	if err := json.Unmarshal(localContents, &report2); err != nil {
+		return "", fmt.Errorf("failed to unmarshal local report for %s: %v", expiryDate, err)
+	}
+
+	var uploadContents []byte
+	if uploadOK {
+		// 2. create the uploadable version
+		cfg := config.NewConfig(u.config)
+		upload := &telemetry.Report{
+			Week:     report.Week,
+			LastWeek: report.LastWeek,
+			X:        report.X,
+			Config:   report.Config,
+		}
+		for _, p := range report.Programs {
+			// does the uploadConfig want this program?
+			// if so, copy over the Stacks and Counters
+			// that the uploadConfig mentions.
+			if !cfg.HasGoVersion(p.GoVersion) || !cfg.HasProgram(p.Program) || !cfg.HasVersion(p.Program, p.Version) {
+				continue
+			}
+			x := &telemetry.ProgramReport{
+				Program:   p.Program,
+				Version:   p.Version,
+				GOOS:      p.GOOS,
+				GOARCH:    p.GOARCH,
+				GoVersion: p.GoVersion,
+				Counters:  make(map[string]int64),
+				Stacks:    make(map[string]int64),
+			}
+			upload.Programs = append(upload.Programs, x)
+			for k, v := range p.Counters {
+				if cfg.HasCounter(p.Program, k) && report.X <= cfg.Rate(p.Program, k) {
+					x.Counters[k] = v
+				}
+			}
+			// and the same for Stacks
+			// this can be made more efficient, when it matters
+			for k, v := range p.Stacks {
+				before, _, _ := strings.Cut(k, "\n")
+				if cfg.HasStack(p.Program, before) && report.X <= cfg.Rate(p.Program, before) {
+					x.Stacks[k] = v
+				}
+			}
+		}
+
+		uploadContents, err = json.MarshalIndent(upload, "", " ")
+		if err != nil {
+			return "", fmt.Errorf("failed to marshal upload report for %s: %v", expiryDate, err)
+		}
+	}
+	localFileName := filepath.Join(u.dir.LocalDir(), "local."+expiryDate+".json")
+	uploadFileName := filepath.Join(u.dir.LocalDir(), expiryDate+".json")
+
+	/* Prepare to write files */
+	// if either file exists, someone has been here ahead of us
+	// (there is still a race, but this check shortens the open window)
+	if _, err := os.Stat(localFileName); err == nil {
+		u.deleteFiles(countFiles)
+		return "", fmt.Errorf("local report %s already exists", localFileName)
+	}
+	if _, err := os.Stat(uploadFileName); err == nil {
+		u.deleteFiles(countFiles)
+		return "", fmt.Errorf("report %s already exists", uploadFileName)
+	}
+	// write the uploadable file
+	var errUpload, errLocal error
+	if uploadOK {
+		_, errUpload = exclusiveWrite(uploadFileName, uploadContents)
+	}
+	// write the local file
+	_, errLocal = exclusiveWrite(localFileName, localContents)
+	/*  Wrote the files */
+
+	// even though these errors won't occur, what should happen
+	// if errUpload == nil and it is ok to upload, and errLocal != nil?
+	if errLocal != nil {
+		return "", fmt.Errorf("failed to write local file %s (%v)", localFileName, errLocal)
+	}
+	if errUpload != nil {
+		return "", fmt.Errorf("failed to write upload file %s (%v)", uploadFileName, errUpload)
+	}
+	u.logger.Printf("Created %s, deleting %d count files", filepath.Base(uploadFileName), len(countFiles))
+	u.deleteFiles(countFiles)
+	if uploadOK {
+		return uploadFileName, nil
+	}
+	return "", nil
+}
+
+// exclusiveWrite attempts to create filename exclusively, and if successful,
+// writes content to the resulting file handle.
+//
+// It returns a boolean indicating whether the exclusive handle was acquired,
+// and an error indicating whether the operation succeeded.
+// If the file already exists, exclusiveWrite returns (false, nil).
+func exclusiveWrite(filename string, content []byte) (_ bool, rerr error) {
+	f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644)
+	if err != nil {
+		if os.IsExist(err) {
+			return false, nil
+		}
+		return false, err
+	}
+	defer func() {
+		if err := f.Close(); err != nil && rerr == nil {
+			rerr = err
+		}
+	}()
+	if _, err := f.Write(content); err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
+// return an existing ProgremReport, or create anew
+func findProgReport(meta map[string]string, report *telemetry.Report) *telemetry.ProgramReport {
+	for _, prog := range report.Programs {
+		if prog.Program == meta["Program"] && prog.Version == meta["Version"] &&
+			prog.GoVersion == meta["GoVersion"] && prog.GOOS == meta["GOOS"] &&
+			prog.GOARCH == meta["GOARCH"] {
+			return prog
+		}
+	}
+	prog := telemetry.ProgramReport{
+		Program:   meta["Program"],
+		Version:   meta["Version"],
+		GoVersion: meta["GoVersion"],
+		GOOS:      meta["GOOS"],
+		GOARCH:    meta["GOARCH"],
+		Counters:  make(map[string]int64),
+		Stacks:    make(map[string]int64),
+	}
+	report.Programs = append(report.Programs, &prog)
+	return &prog
+}
+
+// computeRandom returns a cryptographic random float64 in the range [0, 1],
+// with 52 bits of precision.
+func computeRandom() float64 {
+	for {
+		b := make([]byte, 8)
+		_, err := rand.Read(b)
+		if err != nil {
+			panic(fmt.Sprintf("rand.Read failed: %v", err))
+		}
+		// and turn it into a float64
+		x := math.Float64frombits(binary.LittleEndian.Uint64(b))
+		if math.IsNaN(x) || math.IsInf(x, 0) {
+			continue
+		}
+		x = math.Abs(x)
+		if x < 0x1p-1000 { // avoid underflow patterns
+			continue
+		}
+		frac, _ := math.Frexp(x) // 52 bits of randomness
+		return frac*2 - 1
+	}
+}

vendor/golang.org/x/telemetry/internal/upload/run.go

@@ -0,0 +1,226 @@
+// Copyright 2023 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 upload
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime/debug"
+	"strings"
+	"time"
+
+	"golang.org/x/telemetry/internal/configstore"
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+// RunConfig configures non-default behavior of a call to Run.
+//
+// All fields are optional, for testing or observability.
+type RunConfig struct {
+	TelemetryDir string    // if set, overrides the telemetry data directory
+	UploadURL    string    // if set, overrides the telemetry upload endpoint
+	LogWriter    io.Writer // if set, used for detailed logging of the upload process
+	Env          []string  // if set, appended to the config download environment
+	StartTime    time.Time // if set, overrides the upload start time
+}
+
+// Run generates and uploads reports, as allowed by the mode file.
+func Run(config RunConfig) error {
+	defer func() {
+		if err := recover(); err != nil {
+			log.Printf("upload recover: %v", err)
+		}
+	}()
+	uploader, err := newUploader(config)
+	if err != nil {
+		return err
+	}
+	defer uploader.Close()
+	return uploader.Run()
+}
+
+// uploader encapsulates a single upload operation, carrying parameters and
+// shared state.
+type uploader struct {
+	// config is used to select counters to upload.
+	config        *telemetry.UploadConfig //
+	configVersion string                  // version of the config
+	dir           telemetry.Dir           // the telemetry dir to process
+
+	uploadServerURL string
+	startTime       time.Time
+
+	cache parsedCache
+
+	logFile *os.File
+	logger  *log.Logger
+}
+
+// newUploader creates a new uploader to use for running the upload for the
+// given config.
+//
+// Uploaders should only be used for one call to [uploader.Run].
+func newUploader(rcfg RunConfig) (*uploader, error) {
+	// Determine the upload directory.
+	var dir telemetry.Dir
+	if rcfg.TelemetryDir != "" {
+		dir = telemetry.NewDir(rcfg.TelemetryDir)
+	} else {
+		dir = telemetry.Default
+	}
+
+	// Determine the upload URL.
+	uploadURL := rcfg.UploadURL
+	if uploadURL == "" {
+		uploadURL = "https://telemetry.go.dev/upload"
+	}
+
+	// Determine the upload logger.
+	//
+	// This depends on the provided rcfg.LogWriter and the presence of
+	// dir.DebugDir, as follows:
+	//  1. If LogWriter is present, log to it.
+	//  2. If DebugDir is present, log to a file within it.
+	//  3. If both LogWriter and DebugDir are present, log to a multi writer.
+	//  4. If neither LogWriter nor DebugDir are present, log to a noop logger.
+	var logWriters []io.Writer
+	logFile, err := debugLogFile(dir.DebugDir())
+	if err != nil {
+		logFile = nil
+	}
+	if logFile != nil {
+		logWriters = append(logWriters, logFile)
+	}
+	if rcfg.LogWriter != nil {
+		logWriters = append(logWriters, rcfg.LogWriter)
+	}
+	var logWriter io.Writer
+	switch len(logWriters) {
+	case 0:
+		logWriter = io.Discard
+	case 1:
+		logWriter = logWriters[0]
+	default:
+		logWriter = io.MultiWriter(logWriters...)
+	}
+	logger := log.New(logWriter, "", log.Ltime|log.Lmicroseconds|log.Lshortfile)
+
+	// Fetch the upload config, if it is not provided.
+	var (
+		config        *telemetry.UploadConfig
+		configVersion string
+	)
+
+	if mode, _ := dir.Mode(); mode == "on" {
+		// golang/go#68946: only download the upload config if it will be used.
+		//
+		// TODO(rfindley): This is a narrow change aimed at minimally fixing the
+		// associated bug. In the future, we should read the mode only once during
+		// the upload process.
+		config, configVersion, err = configstore.Download("latest", rcfg.Env)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		config = &telemetry.UploadConfig{}
+		configVersion = "v0.0.0-0"
+	}
+
+	// Set the start time, if it is not provided.
+	startTime := time.Now().UTC()
+	if !rcfg.StartTime.IsZero() {
+		startTime = rcfg.StartTime
+	}
+
+	return &uploader{
+		config:          config,
+		configVersion:   configVersion,
+		dir:             dir,
+		uploadServerURL: uploadURL,
+		startTime:       startTime,
+
+		logFile: logFile,
+		logger:  logger,
+	}, nil
+}
+
+// Close cleans up any resources associated with the uploader.
+func (u *uploader) Close() error {
+	if u.logFile == nil {
+		return nil
+	}
+	return u.logFile.Close()
+}
+
+// Run generates and uploads reports
+func (u *uploader) Run() error {
+	if telemetry.DisabledOnPlatform {
+		return nil
+	}
+	todo := u.findWork()
+	ready, err := u.reports(&todo)
+	if err != nil {
+		u.logger.Printf("Error building reports: %v", err)
+		return fmt.Errorf("reports failed: %v", err)
+	}
+	u.logger.Printf("Uploading %d reports", len(ready))
+	for _, f := range ready {
+		u.uploadReport(f)
+	}
+	return nil
+}
+
+// debugLogFile arranges to write a log file in the given debug directory, if
+// it exists.
+func debugLogFile(debugDir string) (*os.File, error) {
+	fd, err := os.Stat(debugDir)
+	if os.IsNotExist(err) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	if !fd.IsDir() {
+		return nil, fmt.Errorf("debug path %q is not a directory", debugDir)
+	}
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return nil, fmt.Errorf("no build info")
+	}
+	year, month, day := time.Now().UTC().Date()
+	goVers := info.GoVersion
+	// E.g.,  goVers:"go1.22-20240109-RC01 cl/597041403 +dcbe772469 X:loopvar"
+	words := strings.Fields(goVers)
+	goVers = words[0]
+	progPkgPath := info.Path
+	if progPkgPath == "" {
+		progPkgPath = strings.TrimSuffix(filepath.Base(os.Args[0]), ".exe")
+	}
+	prog := path.Base(progPkgPath)
+	progVers := info.Main.Version
+	if progVers == "(devel)" { // avoid special characters in created file names
+		progVers = "devel"
+	}
+	logBase := strings.ReplaceAll(
+		fmt.Sprintf("%s-%s-%s-%4d%02d%02d-%d.log", prog, progVers, goVers, year, month, day, os.Getpid()),
+		" ", "")
+	fname := filepath.Join(debugDir, logBase)
+	if _, err := os.Stat(fname); err == nil {
+		// This process previously called upload.Run
+		return nil, nil
+	}
+	f, err := os.OpenFile(fname, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
+	if err != nil {
+		if os.IsExist(err) {
+			return nil, nil // this process previously called upload.Run
+		}
+		return nil, err
+	}
+	return f, nil
+}

vendor/golang.org/x/telemetry/internal/upload/upload.go

@@ -0,0 +1,117 @@
+// Copyright 2023 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 upload
+
+import (
+	"bytes"
+	"net/http"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+
+	"golang.org/x/telemetry/internal/telemetry"
+)
+
+var (
+	dateRE     = regexp.MustCompile(`(\d\d\d\d-\d\d-\d\d)[.]json$`)
+	dateFormat = telemetry.DateOnly
+	// TODO(rfindley): use dateFormat throughout.
+)
+
+// uploadReportDate returns the date component of the upload file name, or "" if the
+// date was unmatched.
+func (u *uploader) uploadReportDate(fname string) time.Time {
+	match := dateRE.FindStringSubmatch(fname)
+	if match == nil || len(match) < 2 {
+		u.logger.Printf("malformed report name: missing date: %q", filepath.Base(fname))
+		return time.Time{}
+	}
+	d, err := time.Parse(dateFormat, match[1])
+	if err != nil {
+		u.logger.Printf("malformed report name: bad date: %q", filepath.Base(fname))
+		return time.Time{}
+	}
+	return d
+}
+
+func (u *uploader) uploadReport(fname string) {
+	thisInstant := u.startTime
+	// TODO(rfindley): use uploadReportDate here, once we've done a gopls release.
+
+	// first make sure it is not in the future
+	today := thisInstant.Format(telemetry.DateOnly)
+	match := dateRE.FindStringSubmatch(fname)
+	if match == nil || len(match) < 2 {
+		u.logger.Printf("Report name %q missing date", filepath.Base(fname))
+	} else if match[1] > today {
+		u.logger.Printf("Report date for %q is later than today (%s)", filepath.Base(fname), today)
+		return // report is in the future, which shouldn't happen
+	}
+	buf, err := os.ReadFile(fname)
+	if err != nil {
+		u.logger.Printf("%v reading %s", err, fname)
+		return
+	}
+	if u.uploadReportContents(fname, buf) {
+		// anything left to do?
+	}
+}
+
+// try to upload the report, 'true' if successful
+func (u *uploader) uploadReportContents(fname string, buf []byte) bool {
+	fdate := strings.TrimSuffix(filepath.Base(fname), ".json")
+	fdate = fdate[len(fdate)-len(telemetry.DateOnly):]
+
+	newname := filepath.Join(u.dir.UploadDir(), fdate+".json")
+
+	// Lock the upload, to prevent duplicate uploads.
+	{
+		lockname := newname + ".lock"
+		lockfile, err := os.OpenFile(lockname, os.O_CREATE|os.O_EXCL, 0666)
+		if err != nil {
+			u.logger.Printf("Failed to acquire lock %s: %v", lockname, err)
+			return false
+		}
+		_ = lockfile.Close()
+		defer os.Remove(lockname)
+	}
+
+	if _, err := os.Stat(newname); err == nil {
+		// Another process uploaded but failed to clean up (or hasn't yet cleaned
+		// up). Ensure that cleanup occurs.
+		u.logger.Printf("After acquire: report already uploaded")
+		_ = os.Remove(fname)
+		return false
+	}
+
+	endpoint := u.uploadServerURL + "/" + fdate
+	b := bytes.NewReader(buf)
+	resp, err := http.Post(endpoint, "application/json", b)
+	if err != nil {
+		u.logger.Printf("Error upload %s to %s: %v", filepath.Base(fname), endpoint, err)
+		return false
+	}
+	// hope for a 200, remove file on a 4xx, otherwise it will be retried by another process
+	if resp.StatusCode != 200 {
+		u.logger.Printf("Failed to upload %s to %s: %s", filepath.Base(fname), endpoint, resp.Status)
+		if resp.StatusCode >= 400 && resp.StatusCode < 500 {
+			err := os.Remove(fname)
+			if err == nil {
+				u.logger.Printf("Removed local/%s", filepath.Base(fname))
+			} else {
+				u.logger.Printf("Error removing local/%s: %v", filepath.Base(fname), err)
+			}
+		}
+		return false
+	}
+	// Store a copy of the uploaded report in the uploaded directory.
+	if err := os.WriteFile(newname, buf, 0644); err == nil {
+		os.Remove(fname) // if it exists
+	}
+	u.logger.Printf("Uploaded %s to %q", fdate+".json", endpoint)
+	return true
+}