src/cmd/pprof/pprof.go - go - Git at Google

 // Copyright 2014 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.

 // pprof is a tool for visualization of profile.data. It is based on
 // the upstream version at github.com/google/pprof, with minor
 // modifications specific to the Go distribution. Please consider
 // upstreaming any modifications to these packages.

 package main

 import (
 	"crypto/tls"
 	"debug/dwarf"
 	"fmt"
 	"io"
 	"net/http"
 	"net/url"
 	"os"
 	"regexp"
 	"strconv"
 	"strings"
 	"sync"
 	"time"

 	"cmd/internal/objfile"

 	"github.com/google/pprof/driver"
 	"github.com/google/pprof/profile"
 )

 func main() {
 	options := &driver.Options{
 		Fetch: new(fetcher),
 		Obj:   new(objTool),
 		UI:    newUI(),
 	}
 	if err := driver.PProf(options); err != nil {
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		os.Exit(2)
 	}
 }

 type fetcher struct {
 }

 func (f *fetcher) Fetch(src string, duration, timeout time.Duration) (*profile.Profile, string, error) {
 	sourceURL, timeout := adjustURL(src, duration, timeout)
 	if sourceURL == "" {
 		// Could not recognize URL, let regular pprof attempt to fetch the profile (eg. from a file)
 		return nil, "", nil
 	}
 	fmt.Fprintln(os.Stderr, "Fetching profile over HTTP from", sourceURL)
 	if duration > 0 {
 		fmt.Fprintf(os.Stderr, "Please wait... (%v)\n", duration)
 	}
 	p, err := getProfile(sourceURL, timeout)
 	return p, sourceURL, err
 }

 func getProfile(source string, timeout time.Duration) (*profile.Profile, error) {
 	url, err := url.Parse(source)
 	if err != nil {
 		return nil, err
 	}

 	var tlsConfig *tls.Config
 	if url.Scheme == "https+insecure" {
 		tlsConfig = &tls.Config{
 			InsecureSkipVerify: true,
 		}
 		url.Scheme = "https"
 		source = url.String()
 	}

 	client := &http.Client{
 		Transport: &http.Transport{
 			ResponseHeaderTimeout: timeout + 5*time.Second,
 			Proxy:                 http.ProxyFromEnvironment,
 			TLSClientConfig:       tlsConfig,
 		},
 	}
 	resp, err := client.Get(source)
 	if err != nil {
 		return nil, err
 	}
 	if resp.StatusCode != http.StatusOK {
 		defer resp.Body.Close()
 		return nil, statusCodeError(resp)
 	}
 	return profile.Parse(resp.Body)
 }

 func statusCodeError(resp *http.Response) error {
 	if resp.Header.Get("X-Go-Pprof") != "" && strings.Contains(resp.Header.Get("Content-Type"), "text/plain") {
 		// error is from pprof endpoint
 		if body, err := io.ReadAll(resp.Body); err == nil {
 			return fmt.Errorf("server response: %s - %s", resp.Status, body)
 		}
 	}
 	return fmt.Errorf("server response: %s", resp.Status)
 }

 // cpuProfileHandler is the Go pprof CPU profile handler URL.
 const cpuProfileHandler = "/debug/pprof/profile"

 // adjustURL applies the duration/timeout values and Go specific defaults
 func adjustURL(source string, duration, timeout time.Duration) (string, time.Duration) {
 	u, err := url.Parse(source)
 	if err != nil || (u.Host == "" && u.Scheme != "" && u.Scheme != "file") {
 		// Try adding http:// to catch sources of the form hostname:port/path.
 		// url.Parse treats "hostname" as the scheme.
 		u, err = url.Parse("http://" + source)
 	}
 	if err != nil || u.Host == "" {
 		return "", 0
 	}

 	if u.Path == "" || u.Path == "/" {
 		u.Path = cpuProfileHandler
 	}

 	// Apply duration/timeout overrides to URL.
 	values := u.Query()
 	if duration > 0 {
 		values.Set("seconds", fmt.Sprint(int(duration.Seconds())))
 	} else {
 		if urlSeconds := values.Get("seconds"); urlSeconds != "" {
 			if us, err := strconv.ParseInt(urlSeconds, 10, 32); err == nil {
 				duration = time.Duration(us) * time.Second
 			}
 		}
 	}
 	if timeout <= 0 {
 		if duration > 0 {
 			timeout = duration + duration/2
 		} else {
 			timeout = 60 * time.Second
 		}
 	}
 	u.RawQuery = values.Encode()
 	return u.String(), timeout
 }

 // objTool implements driver.ObjTool using Go libraries
 // (instead of invoking GNU binutils).
 type objTool struct {
 	mu          sync.Mutex
 	disasmCache map[string]*objfile.Disasm
 }

 func (*objTool) Open(name string, start, limit, offset uint64, relocationSymbol string) (driver.ObjFile, error) {
 	of, err := objfile.Open(name)
 	if err != nil {
 		return nil, err
 	}
 	f := &file{
 		name: name,
 		file: of,
 	}
 	if start != 0 {
 		if load, err := of.LoadAddress(); err == nil {
 			f.offset = start - load
 		}
 	}
 	return f, nil
 }

 func (*objTool) Demangle(names []string) (map[string]string, error) {
 	// No C++, nothing to demangle.
 	return make(map[string]string), nil
 }

 func (t *objTool) Disasm(file string, start, end uint64, intelSyntax bool) ([]driver.Inst, error) {
 	if intelSyntax {
 		return nil, fmt.Errorf("printing assembly in Intel syntax is not supported")
 	}
 	d, err := t.cachedDisasm(file)
 	if err != nil {
 		return nil, err
 	}
 	var asm []driver.Inst
 	d.Decode(start, end, nil, false, func(pc, size uint64, file string, line int, text string) {
 		asm = append(asm, driver.Inst{Addr: pc, File: file, Line: line, Text: text})
 	})
 	return asm, nil
 }

 func (t *objTool) cachedDisasm(file string) (*objfile.Disasm, error) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 	if t.disasmCache == nil {
 		t.disasmCache = make(map[string]*objfile.Disasm)
 	}
 	d := t.disasmCache[file]
 	if d != nil {
 		return d, nil
 	}
 	f, err := objfile.Open(file)
 	if err != nil {
 		return nil, err
 	}
 	d, err = f.Disasm()
 	f.Close()
 	if err != nil {
 		return nil, err
 	}
 	t.disasmCache[file] = d
 	return d, nil
 }

 func (*objTool) SetConfig(config string) {
 	// config is usually used to say what binaries to invoke.
 	// Ignore entirely.
 }

 // file implements driver.ObjFile using Go libraries
 // (instead of invoking GNU binutils).
 // A file represents a single executable being analyzed.
 type file struct {
 	name   string
 	offset uint64
 	sym    []objfile.Sym
 	file   *objfile.File
 	pcln   objfile.Liner

 	triedDwarf bool
 	dwarf      *dwarf.Data
 }

 func (f *file) Name() string {
 	return f.name
 }

 func (f *file) ObjAddr(addr uint64) (uint64, error) {
 	// No support for shared libraries, so translation is a no-op.
 	return addr, nil
 }

 func (f *file) BuildID() string {
 	// No support for build ID.
 	return ""
 }

 func (f *file) SourceLine(addr uint64) ([]driver.Frame, error) {
 	if f.pcln == nil {
 		pcln, err := f.file.PCLineTable()
 		if err != nil {
 			return nil, err
 		}
 		f.pcln = pcln
 	}
 	addr -= f.offset
 	file, line, fn := f.pcln.PCToLine(addr)
 	if fn != nil {
 		frame := []driver.Frame{
 			{
 				Func: fn.Name,
 				File: file,
 				Line: line,
 			},
 		}
 		return frame, nil
 	}

 	frames := f.dwarfSourceLine(addr)
 	if frames != nil {
 		return frames, nil
 	}

 	return nil, fmt.Errorf("no line information for PC=%#x", addr)
 }

 // dwarfSourceLine tries to get file/line information using DWARF.
 // This is for C functions that appear in the profile.
 // Returns nil if there is no information available.
 func (f *file) dwarfSourceLine(addr uint64) []driver.Frame {
 	if f.dwarf == nil && !f.triedDwarf {
 		// Ignore any error--we don't care exactly why there
 		// is no DWARF info.
 		f.dwarf, _ = f.file.DWARF()
 		f.triedDwarf = true
 	}

 	if f.dwarf != nil {
 		r := f.dwarf.Reader()
 		unit, err := r.SeekPC(addr)
 		if err == nil {
 			if frames := f.dwarfSourceLineEntry(r, unit, addr); frames != nil {
 				return frames
 			}
 		}
 	}

 	return nil
 }

 // dwarfSourceLineEntry tries to get file/line information from a
 // DWARF compilation unit. Returns nil if it doesn't find anything.
 func (f *file) dwarfSourceLineEntry(r *dwarf.Reader, entry *dwarf.Entry, addr uint64) []driver.Frame {
 	lines, err := f.dwarf.LineReader(entry)
 	if err != nil {
 		return nil
 	}
 	var lentry dwarf.LineEntry
 	if err := lines.SeekPC(addr, &lentry); err != nil {
 		return nil
 	}

 	// Try to find the function name.
 	name := ""
 FindName:
 	for entry, err := r.Next(); entry != nil && err == nil; entry, err = r.Next() {
 		if entry.Tag == dwarf.TagSubprogram {
 			ranges, err := f.dwarf.Ranges(entry)
 			if err != nil {
 				return nil
 			}
 			for _, pcs := range ranges {
 				if pcs[0] <= addr && addr < pcs[1] {
 					var ok bool
 					// TODO: AT_linkage_name, AT_MIPS_linkage_name.
 					name, ok = entry.Val(dwarf.AttrName).(string)
 					if ok {
 						break FindName
 					}
 				}
 			}
 		}
 	}

 	// TODO: Report inlined functions.

 	frames := []driver.Frame{
 		{
 			Func: name,
 			File: lentry.File.Name,
 			Line: lentry.Line,
 		},
 	}

 	return frames
 }

 func (f *file) Symbols(r *regexp.Regexp, addr uint64) ([]*driver.Sym, error) {
 	if f.sym == nil {
 		sym, err := f.file.Symbols()
 		if err != nil {
 			return nil, err
 		}
 		f.sym = sym
 	}
 	var out []*driver.Sym
 	for _, s := range f.sym {
 		// Ignore a symbol with address 0 and size 0.
 		// An ELF STT_FILE symbol will look like that.
 		if s.Addr == 0 && s.Size == 0 {
 			continue
 		}
 		if (r == nil || r.MatchString(s.Name)) && (addr == 0 || s.Addr <= addr && addr < s.Addr+uint64(s.Size)) {
 			out = append(out, &driver.Sym{
 				Name:  []string{s.Name},
 				File:  f.name,
 				Start: s.Addr,
 				End:   s.Addr + uint64(s.Size) - 1,
 			})
 		}
 	}
 	return out, nil
 }

 func (f *file) Close() error {
 	f.file.Close()
 	return nil
 }

 // newUI will be set in readlineui.go in some platforms
 // for interactive readline functionality.
 var newUI = func() driver.UI { return nil }
	// Copyright 2014 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.

	// pprof is a tool for visualization of profile.data. It is based on
	// the upstream version at github.com/google/pprof, with minor
	// modifications specific to the Go distribution. Please consider
	// upstreaming any modifications to these packages.

	package main

	import (
	"crypto/tls"
	"debug/dwarf"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"regexp"
	"strconv"
	"strings"
	"sync"
	"time"

	"cmd/internal/objfile"

	"github.com/google/pprof/driver"
	"github.com/google/pprof/profile"
	)

	func main() {
	options := &driver.Options{
	Fetch: new(fetcher),
	Obj: new(objTool),
	UI: newUI(),
	}
	if err := driver.PProf(options); err != nil {
	fmt.Fprintf(os.Stderr, "%v\n", err)
	os.Exit(2)
	}
	}

	type fetcher struct {
	}

	func (f fetcher) Fetch(src string, duration, timeout time.Duration) (profile.Profile, string, error) {
	sourceURL, timeout := adjustURL(src, duration, timeout)
	if sourceURL == "" {
	// Could not recognize URL, let regular pprof attempt to fetch the profile (eg. from a file)
	return nil, "", nil
	}
	fmt.Fprintln(os.Stderr, "Fetching profile over HTTP from", sourceURL)
	if duration > 0 {
	fmt.Fprintf(os.Stderr, "Please wait... (%v)\n", duration)
	}
	p, err := getProfile(sourceURL, timeout)
	return p, sourceURL, err
	}

	func getProfile(source string, timeout time.Duration) (*profile.Profile, error) {
	url, err := url.Parse(source)
	if err != nil {
	return nil, err
	}

	var tlsConfig *tls.Config
	if url.Scheme == "https+insecure" {
	tlsConfig = &tls.Config{
	InsecureSkipVerify: true,
	}
	url.Scheme = "https"
	source = url.String()
	}

	client := &http.Client{
	Transport: &http.Transport{
	ResponseHeaderTimeout: timeout + 5*time.Second,
	Proxy: http.ProxyFromEnvironment,
	TLSClientConfig: tlsConfig,
	},
	}
	resp, err := client.Get(source)
	if err != nil {
	return nil, err
	}
	if resp.StatusCode != http.StatusOK {
	defer resp.Body.Close()
	return nil, statusCodeError(resp)
	}
	return profile.Parse(resp.Body)
	}

	func statusCodeError(resp *http.Response) error {
	if resp.Header.Get("X-Go-Pprof") != "" && strings.Contains(resp.Header.Get("Content-Type"), "text/plain") {
	// error is from pprof endpoint
	if body, err := io.ReadAll(resp.Body); err == nil {
	return fmt.Errorf("server response: %s - %s", resp.Status, body)
	}
	}
	return fmt.Errorf("server response: %s", resp.Status)
	}

	// cpuProfileHandler is the Go pprof CPU profile handler URL.
	const cpuProfileHandler = "/debug/pprof/profile"

	// adjustURL applies the duration/timeout values and Go specific defaults
	func adjustURL(source string, duration, timeout time.Duration) (string, time.Duration) {
	u, err := url.Parse(source)
	if err != nil \|\| (u.Host == "" && u.Scheme != "" && u.Scheme != "file") {
	// Try adding http:// to catch sources of the form hostname:port/path.
	// url.Parse treats "hostname" as the scheme.
	u, err = url.Parse("http://" + source)
	}
	if err != nil \|\| u.Host == "" {
	return "", 0
	}

	if u.Path == "" \|\| u.Path == "/" {
	u.Path = cpuProfileHandler
	}

	// Apply duration/timeout overrides to URL.
	values := u.Query()
	if duration > 0 {
	values.Set("seconds", fmt.Sprint(int(duration.Seconds())))
	} else {
	if urlSeconds := values.Get("seconds"); urlSeconds != "" {
	if us, err := strconv.ParseInt(urlSeconds, 10, 32); err == nil {
	duration = time.Duration(us) * time.Second
	}
	}
	}
	if timeout <= 0 {
	if duration > 0 {
	timeout = duration + duration/2
	} else {
	timeout = 60 * time.Second
	}
	}
	u.RawQuery = values.Encode()
	return u.String(), timeout
	}

	// objTool implements driver.ObjTool using Go libraries
	// (instead of invoking GNU binutils).
	type objTool struct {
	mu sync.Mutex
	disasmCache map[string]*objfile.Disasm
	}

	func (*objTool) Open(name string, start, limit, offset uint64, relocationSymbol string) (driver.ObjFile, error) {
	of, err := objfile.Open(name)
	if err != nil {
	return nil, err
	}
	f := &file{
	name: name,
	file: of,
	}
	if start != 0 {
	if load, err := of.LoadAddress(); err == nil {
	f.offset = start - load
	}
	}
	return f, nil
	}

	func (*objTool) Demangle(names []string) (map[string]string, error) {
	// No C++, nothing to demangle.
	return make(map[string]string), nil
	}

	func (t *objTool) Disasm(file string, start, end uint64, intelSyntax bool) ([]driver.Inst, error) {
	if intelSyntax {
	return nil, fmt.Errorf("printing assembly in Intel syntax is not supported")
	}
	d, err := t.cachedDisasm(file)
	if err != nil {
	return nil, err
	}
	var asm []driver.Inst
	d.Decode(start, end, nil, false, func(pc, size uint64, file string, line int, text string) {
	asm = append(asm, driver.Inst{Addr: pc, File: file, Line: line, Text: text})
	})
	return asm, nil
	}

	func (t objTool) cachedDisasm(file string) (objfile.Disasm, error) {
	t.mu.Lock()
	defer t.mu.Unlock()
	if t.disasmCache == nil {
	t.disasmCache = make(map[string]*objfile.Disasm)
	}
	d := t.disasmCache[file]
	if d != nil {
	return d, nil
	}
	f, err := objfile.Open(file)
	if err != nil {
	return nil, err
	}
	d, err = f.Disasm()
	f.Close()
	if err != nil {
	return nil, err
	}
	t.disasmCache[file] = d
	return d, nil
	}

	func (*objTool) SetConfig(config string) {
	// config is usually used to say what binaries to invoke.
	// Ignore entirely.
	}

	// file implements driver.ObjFile using Go libraries
	// (instead of invoking GNU binutils).
	// A file represents a single executable being analyzed.
	type file struct {
	name string
	offset uint64
	sym []objfile.Sym
	file *objfile.File
	pcln objfile.Liner

	triedDwarf bool
	dwarf *dwarf.Data
	}

	func (f *file) Name() string {
	return f.name
	}

	func (f *file) ObjAddr(addr uint64) (uint64, error) {
	// No support for shared libraries, so translation is a no-op.
	return addr, nil
	}

	func (f *file) BuildID() string {
	// No support for build ID.
	return ""
	}

	func (f *file) SourceLine(addr uint64) ([]driver.Frame, error) {
	if f.pcln == nil {
	pcln, err := f.file.PCLineTable()
	if err != nil {
	return nil, err
	}
	f.pcln = pcln
	}
	addr -= f.offset
	file, line, fn := f.pcln.PCToLine(addr)
	if fn != nil {
	frame := []driver.Frame{
	{
	Func: fn.Name,
	File: file,
	Line: line,
	},
	}
	return frame, nil
	}

	frames := f.dwarfSourceLine(addr)
	if frames != nil {
	return frames, nil
	}

	return nil, fmt.Errorf("no line information for PC=%#x", addr)
	}

	// dwarfSourceLine tries to get file/line information using DWARF.
	// This is for C functions that appear in the profile.
	// Returns nil if there is no information available.
	func (f *file) dwarfSourceLine(addr uint64) []driver.Frame {
	if f.dwarf == nil && !f.triedDwarf {
	// Ignore any error--we don't care exactly why there
	// is no DWARF info.
	f.dwarf, _ = f.file.DWARF()
	f.triedDwarf = true
	}

	if f.dwarf != nil {
	r := f.dwarf.Reader()
	unit, err := r.SeekPC(addr)
	if err == nil {
	if frames := f.dwarfSourceLineEntry(r, unit, addr); frames != nil {
	return frames
	}
	}
	}

	return nil
	}

	// dwarfSourceLineEntry tries to get file/line information from a
	// DWARF compilation unit. Returns nil if it doesn't find anything.
	func (f file) dwarfSourceLineEntry(r dwarf.Reader, entry *dwarf.Entry, addr uint64) []driver.Frame {
	lines, err := f.dwarf.LineReader(entry)
	if err != nil {
	return nil
	}
	var lentry dwarf.LineEntry
	if err := lines.SeekPC(addr, &lentry); err != nil {
	return nil
	}

	// Try to find the function name.
	name := ""
	FindName:
	for entry, err := r.Next(); entry != nil && err == nil; entry, err = r.Next() {
	if entry.Tag == dwarf.TagSubprogram {
	ranges, err := f.dwarf.Ranges(entry)
	if err != nil {
	return nil
	}
	for _, pcs := range ranges {
	if pcs[0] <= addr && addr < pcs[1] {
	var ok bool
	// TODO: AT_linkage_name, AT_MIPS_linkage_name.
	name, ok = entry.Val(dwarf.AttrName).(string)
	if ok {
	break FindName
	}
	}
	}
	}
	}

	// TODO: Report inlined functions.

	frames := []driver.Frame{
	{
	Func: name,
	File: lentry.File.Name,
	Line: lentry.Line,
	},
	}

	return frames
	}

	func (f file) Symbols(r regexp.Regexp, addr uint64) ([]*driver.Sym, error) {
	if f.sym == nil {
	sym, err := f.file.Symbols()
	if err != nil {
	return nil, err
	}
	f.sym = sym
	}
	var out []*driver.Sym
	for _, s := range f.sym {
	// Ignore a symbol with address 0 and size 0.
	// An ELF STT_FILE symbol will look like that.
	if s.Addr == 0 && s.Size == 0 {
	continue
	}
	if (r == nil \|\| r.MatchString(s.Name)) && (addr == 0 \|\| s.Addr <= addr && addr < s.Addr+uint64(s.Size)) {
	out = append(out, &driver.Sym{
	Name: []string{s.Name},
	File: f.name,
	Start: s.Addr,
	End: s.Addr + uint64(s.Size) - 1,
	})
	}
	}
	return out, nil
	}

	func (f *file) Close() error {
	f.file.Close()
	return nil
	}

	// newUI will be set in readlineui.go in some platforms
	// for interactive readline functionality.
	var newUI = func() driver.UI { return nil }