//+build !windows
 

 package daemon
 
 import (

 	"fmt"

 	"os/exec"

 	"regexp"

 	"strconv"
 	"strings"
 

 	"github.com/docker/docker/api/types/container"

 )
 

 func validatePSArgs(psArgs string) error {
 	// NOTE: \\s does not detect unicode whitespaces.
 	// So we use fieldsASCII instead of strings.Fields in parsePSOutput.
 	// See https://github.com/docker/docker/pull/24358
 	re := regexp.MustCompile("\\s+([^\\s]*)=\\s*(PID[^\\s]*)")
 	for _, group := range re.FindAllStringSubmatch(psArgs, -1) {
 		if len(group) >= 3 {
 			k := group[1]
 			v := group[2]
 			if k != "pid" {
 				return fmt.Errorf("specifying \"%s=%s\" is not allowed", k, v)
 			}
 		}

 	}

 	return nil
 }

 // fieldsASCII is similar to strings.Fields but only allows ASCII whitespaces
 func fieldsASCII(s string) []string {
 	fn := func(r rune) bool {
 		switch r {
 		case '\t', '\n', '\f', '\r', ' ':
 			return true
 		}
 		return false

 	}

 	return strings.FieldsFunc(s, fn)
 }

 func parsePSOutput(output []byte, pids []int) (*container.ContainerTopOKBody, error) {
 	procList := &container.ContainerTopOKBody{}

 	lines := strings.Split(string(output), "\n")

 	procList.Titles = fieldsASCII(lines[0])

 	pidIndex := -1

 	for i, name := range procList.Titles {

 		if name == "PID" {
 			pidIndex = i

 		}

 	}
 	if pidIndex == -1 {

 		return nil, fmt.Errorf("Couldn't find PID field in ps output")

 	}

 	// loop through the output and extract the PID from each line

 	for _, line := range lines[1:] {
 		if len(line) == 0 {
 			continue
 		}

 		fields := fieldsASCII(line)

 		p, err := strconv.Atoi(fields[pidIndex])
 		if err != nil {

 			return nil, fmt.Errorf("Unexpected pid '%s': %s", fields[pidIndex], err)

 		}

 		for _, pid := range pids {
 			if pid == p {
 				// Make sure number of fields equals number of header titles
 				// merging "overhanging" fields

 				process := fields[:len(procList.Titles)-1]
 				process = append(process, strings.Join(fields[len(procList.Titles)-1:], " "))
 				procList.Processes = append(procList.Processes, process)

 			}
 		}
 	}

 	return procList, nil
 }
 
 // ContainerTop lists the processes running inside of the given
 // container by calling ps with the given args, or with the flags
 // "-ef" if no args are given.  An error is returned if the container
 // is not found, or is not running, or if there are any problems
 // running ps, or parsing the output.

 func (daemon *Daemon) ContainerTop(name string, psArgs string) (*container.ContainerTopOKBody, error) {

 	if psArgs == "" {
 		psArgs = "-ef"
 	}
 
 	if err := validatePSArgs(psArgs); err != nil {
 		return nil, err
 	}
 
 	container, err := daemon.GetContainer(name)
 	if err != nil {
 		return nil, err
 	}
 
 	if !container.IsRunning() {
 		return nil, errNotRunning{container.ID}
 	}
 
 	if container.IsRestarting() {
 		return nil, errContainerIsRestarting(container.ID)
 	}
 
 	pids, err := daemon.containerd.GetPidsForContainer(container.ID)
 	if err != nil {
 		return nil, err
 	}
 
 	output, err := exec.Command("ps", strings.Split(psArgs, " ")...).Output()
 	if err != nil {
 		return nil, fmt.Errorf("Error running ps: %v", err)
 	}
 	procList, err := parsePSOutput(output, pids)
 	if err != nil {
 		return nil, err
 	}

 	daemon.LogContainerEvent(container, "top")

 	return procList, nil

 }