@@ -1,7 +1,6 @@

 package docker

 import (

-	"bufio"

 	"encoding/json"

 	"errors"

 	"fmt"

@@ -690,34 +689,54 @@ func (srv *Server) ImageHistory(name string) ([]APIHistory, error) {

 func (srv *Server) ContainerTop(name, psArgs string) (*APITop, error) {

 	if container := srv.runtime.Get(name); container != nil {

-		output, err := exec.Command("lxc-ps", "--name", container.ID, "--", psArgs).CombinedOutput()

+		pids, err := utils.GetPidsForContainer(container.ID)

 		if err != nil {

-			return nil, fmt.Errorf("lxc-ps: %s (%s)", err, output)

+			return nil, err

+		}

+		if len(psArgs) == 0 {

+			psArgs = "-ef"

+		}

+		output, err := exec.Command("ps", psArgs).Output()

+		if err != nil {

+			return nil, fmt.Errorf("Error running ps: %s", err)

+		}

+

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

+		header := strings.Fields(lines[0])

+		procs := APITop{

+			Titles: header,

+		}

+

+		pidIndex := -1

+		for i, name := range header {

+			if name == "PID" {

+				pidIndex = i

+			}

 		}

-		procs := APITop{}

-		for i, line := range strings.Split(string(output), "\n") {

+		if pidIndex == -1 {

+			return nil, errors.New("Couldn't find PID field in ps output")

+		}

+

+		for _, line := range lines[1:] {

 			if len(line) == 0 {

 				continue

 			}

-			words := []string{}

-			scanner := bufio.NewScanner(strings.NewReader(line))

-			scanner.Split(bufio.ScanWords)

-			if !scanner.Scan() {

-				return nil, fmt.Errorf("Wrong output using lxc-ps")

+			fields := strings.Fields(line)

+			p, err := strconv.Atoi(fields[pidIndex])

+			if err != nil {

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

 			}

-			// no scanner.Text because we skip container id

-			for scanner.Scan() {

-				if i != 0 && len(words) == len(procs.Titles) {

-					words[len(words)-1] = fmt.Sprintf("%s %s", words[len(words)-1], scanner.Text())

-				} else {

-					words = append(words, scanner.Text())

+

+			for _, pid := range pids {

+				if pid == p {

+					// Make sure number of fields equals number of header titles

+					// merging "overhanging" fields

+					processes := fields[:len(procs.Titles)-1]

+					processes = append(processes, strings.Join(fields[len(procs.Titles)-1:], " "))

+

+					procs.Processes = append(procs.Processes, processes)

 				}

 			}

-			if i == 0 {

-				procs.Titles = words

-			} else {

-				procs.Processes = append(procs.Processes, words)

-			}

 		}

 		return &procs, nil

@@ -1117,3 +1117,59 @@ func CopyFile(src, dst string) (int64, error) {

 	defer df.Close()

 	return io.Copy(df, sf)

 }

+

+// Returns the relative path to the cgroup docker is running in.

+func GetThisCgroup(cgroupType string) (string, error) {

+	output, err := ioutil.ReadFile("/proc/self/cgroup")

+	if err != nil {

+		return "", err

+	}

+	for _, line := range strings.Split(string(output), "\n") {

+		parts := strings.Split(line, ":")

+		// any type used by docker should work

+		if parts[1] == cgroupType {

+			return parts[2], nil

+		}

+	}

+	return "", fmt.Errorf("cgroup '%s' not found in /proc/self/cgroup", cgroupType)

+}

+

+// Returns a list of pids for the given container.

+func GetPidsForContainer(id string) ([]int, error) {

+	pids := []int{}

+

+	// memory is chosen randomly, any cgroup used by docker works

+	cgroupType := "memory"

+

+	cgroupRoot, err := FindCgroupMountpoint(cgroupType)

+	if err != nil {

+		return pids, err

+	}

+

+	cgroupThis, err := GetThisCgroup(cgroupType)

+	if err != nil {

+		return pids, err

+	}

+

+	filename := filepath.Join(cgroupRoot, cgroupThis, id, "tasks")

+	if _, err := os.Stat(filename); os.IsNotExist(err) {

+		// With more recent lxc versions use, cgroup will be in lxc/

+		filename = filepath.Join(cgroupRoot, cgroupThis, "lxc", id, "tasks")

+	}

+

+	output, err := ioutil.ReadFile(filename)

+	if err != nil {

+		return pids, err

+	}

+	for _, p := range strings.Split(string(output), "\n") {

+		if len(p) == 0 {

+			continue

+		}

+		pid, err := strconv.Atoi(p)

+		if err != nil {

+			return pids, fmt.Errorf("Invalid pid '%s': %s", p, err)

+		}

+		pids = append(pids, pid)

+	}

+	return pids, nil

+}