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[process] Fix #607 properly check PID existence #713

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merged 3 commits into from
Jul 27, 2019
Merged

[process] Fix #607 properly check PID existence #713

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5b15bc6
[process][posix] Fix #607 check pid existence with a signal instead o…
Lomanic Jul 6, 2019
4ad0300
[process][windows] Remove magic numbers and useless constants
Lomanic Jul 6, 2019
4a95469
[process][windows] Fix #607 check pid existence with OpenProcess+GetE…
Lomanic Jul 7, 2019
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15 changes: 0 additions & 15 deletions process/process.go
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Original file line number Diff line number Diff line change
Expand Up @@ -139,21 +139,6 @@ func PidExists(pid int32) (bool, error) {
return PidExistsWithContext(context.Background(), pid)
}

func PidExistsWithContext(ctx context.Context, pid int32) (bool, error) {
pids, err := Pids()
if err != nil {
return false, err
}

for _, i := range pids {
if i == pid {
return true, err
}
}

return false, err
}

// Background returns true if the process is in background, false otherwise.
func (p *Process) Background() (bool, error) {
return p.BackgroundWithContext(context.Background())
Expand Down
15 changes: 15 additions & 0 deletions process/process_fallback.go
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,21 @@ func NewProcess(pid int32) (*Process, error) {
return nil, common.ErrNotImplementedError
}

func PidExistsWithContext(ctx context.Context, pid int32) (bool, error) {
pids, err := PidsWithContext(ctx)
if err != nil {
return false, err
}

for _, i := range pids {
if i == pid {
return true, err
}
}

return false, err
}

func (p *Process) Ppid() (int32, error) {
return p.PpidWithContext(context.Background())
}
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29 changes: 29 additions & 0 deletions process/process_posix.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ package process

import (
"context"
"fmt"
"os"
"os/user"
"path/filepath"
Expand Down Expand Up @@ -69,6 +70,34 @@ func getTerminalMap() (map[uint64]string, error) {
return ret, nil
}

func PidExistsWithContext(ctx context.Context, pid int32) (bool, error) {
if pid <= 0 {
return false, fmt.Errorf("invalid pid %v", pid)
}
proc, err := os.FindProcess(int(pid))
if err != nil {
return false, err
}
err = proc.Signal(syscall.Signal(0))
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This line actually breaks the whole story if you are running inside container, and you are tracking host processes.
More details can be found here:
influxdata/telegraf#6813

if err == nil {
return true, nil
}
if err.Error() == "os: process already finished" {
return false, nil
}
errno, ok := err.(syscall.Errno)
if !ok {
return false, err
}
switch errno {
case syscall.ESRCH:
return false, nil
case syscall.EPERM:
return true, nil
}
return false, err
}

// SendSignal sends a unix.Signal to the process.
// Currently, SIGSTOP, SIGCONT, SIGTERM and SIGKILL are supported.
func (p *Process) SendSignal(sig syscall.Signal) error {
Expand Down
68 changes: 48 additions & 20 deletions process/process_windows.go
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Expand Up @@ -19,11 +19,6 @@ import (
"golang.org/x/sys/windows"
)

const (
NoMoreFiles = 0x12
MaxPathLength = 260
)

var (
modpsapi = windows.NewLazySystemDLL("psapi.dll")
procGetProcessMemoryInfo = modpsapi.NewProc("GetProcessMemoryInfo")
Expand Down Expand Up @@ -185,6 +180,44 @@ func PidsWithContext(ctx context.Context) ([]int32, error) {

}

func PidExistsWithContext(ctx context.Context, pid int32) (bool, error) {
if pid == 0 { // special case for pid 0 System Idle Process
return true, nil
}
if pid < 0 {
return false, fmt.Errorf("invalid pid %v", pid)
}
if pid%4 != 0 {
// OpenProcess will succeed even on non-existing pid here https://devblogs.microsoft.com/oldnewthing/20080606-00/?p=22043
// so we list every pid just to be sure and be future-proof
pids, err := PidsWithContext(ctx)
if err != nil {
return false, err
}
for _, i := range pids {
if i == pid {
return true, err
}
}
return false, err
}
const STILL_ACTIVE = 259 // https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-getexitcodeprocess
h, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, uint32(pid))
if err == windows.ERROR_ACCESS_DENIED {
return true, nil
}
if err == windows.ERROR_INVALID_PARAMETER {
return false, nil
}
if err != nil {
return false, err
}
defer syscall.CloseHandle(syscall.Handle(h))
var exitCode uint32
err = windows.GetExitCodeProcess(h, &exitCode)
return exitCode == STILL_ACTIVE, err
}

func (p *Process) Ppid() (int32, error) {
return p.PpidWithContext(context.Background())
}
Expand Down Expand Up @@ -238,12 +271,11 @@ func (p *Process) Exe() (string, error) {
}

func (p *Process) ExeWithContext(ctx context.Context) (string, error) {
// 0x1000 is PROCESS_QUERY_LIMITED_INFORMATION
c, err := syscall.OpenProcess(0x1000, false, uint32(p.Pid))
c, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, uint32(p.Pid))
if err != nil {
return "", err
}
defer syscall.CloseHandle(c)
defer windows.CloseHandle(c)
buf := make([]uint16, syscall.MAX_LONG_PATH)
size := uint32(syscall.MAX_LONG_PATH)
if err := procQueryFullProcessImageNameW.Find(); err == nil { // Vista+
Expand Down Expand Up @@ -346,15 +378,14 @@ func (p *Process) Username() (string, error) {

func (p *Process) UsernameWithContext(ctx context.Context) (string, error) {
pid := p.Pid
// 0x1000 is PROCESS_QUERY_LIMITED_INFORMATION
c, err := syscall.OpenProcess(0x1000, false, uint32(pid))
c, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, uint32(pid))
if err != nil {
return "", err
}
defer syscall.CloseHandle(c)
defer windows.CloseHandle(c)

var token syscall.Token
err = syscall.OpenProcessToken(c, syscall.TOKEN_QUERY, &token)
err = syscall.OpenProcessToken(syscall.Handle(c), syscall.TOKEN_QUERY, &token)
if err != nil {
return "", err
}
Expand Down Expand Up @@ -411,19 +442,18 @@ func (p *Process) Nice() (int32, error) {
}

func (p *Process) NiceWithContext(ctx context.Context) (int32, error) {
// 0x1000 is PROCESS_QUERY_LIMITED_INFORMATION
c, err := syscall.OpenProcess(0x1000, false, uint32(p.Pid))
c, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, uint32(p.Pid))
if err != nil {
return 0, err
}
defer syscall.CloseHandle(c)
defer windows.CloseHandle(c)
ret, _, err := procGetPriorityClass.Call(uintptr(c))
if ret == 0 {
return 0, err
}
priority, ok := priorityClasses[int(ret)]
if !ok {
return 0, fmt.Errorf("unknown priority class %s", ret)
return 0, fmt.Errorf("unknown priority class %v", ret)
}
return priority, nil
}
Expand Down Expand Up @@ -788,8 +818,7 @@ func getRusage(pid int32) (*windows.Rusage, error) {

func getMemoryInfo(pid int32) (PROCESS_MEMORY_COUNTERS, error) {
var mem PROCESS_MEMORY_COUNTERS
// PROCESS_QUERY_LIMITED_INFORMATION is 0x1000
c, err := windows.OpenProcess(0x1000, false, uint32(pid))
c, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, uint32(pid))
if err != nil {
return mem, err
}
Expand Down Expand Up @@ -823,8 +852,7 @@ type SYSTEM_TIMES struct {
func getProcessCPUTimes(pid int32) (SYSTEM_TIMES, error) {
var times SYSTEM_TIMES

// PROCESS_QUERY_LIMITED_INFORMATION is 0x1000
h, err := windows.OpenProcess(0x1000, false, uint32(pid))
h, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, uint32(pid))
if err != nil {
return times, err
}
Expand Down