github.com/portworx/docker@v1.12.1/daemon/top_unix.go (about)

     1  //+build !windows
     2  
     3  package daemon
     4  
     5  import (
     6  	"fmt"
     7  	"os/exec"
     8  	"regexp"
     9  	"strconv"
    10  	"strings"
    11  
    12  	"github.com/docker/engine-api/types"
    13  )
    14  
    15  func validatePSArgs(psArgs string) error {
    16  	// NOTE: \\s does not detect unicode whitespaces.
    17  	// So we use fieldsASCII instead of strings.Fields in parsePSOutput.
    18  	// See https://github.com/docker/docker/pull/24358
    19  	re := regexp.MustCompile("\\s+([^\\s]*)=\\s*(PID[^\\s]*)")
    20  	for _, group := range re.FindAllStringSubmatch(psArgs, -1) {
    21  		if len(group) >= 3 {
    22  			k := group[1]
    23  			v := group[2]
    24  			if k != "pid" {
    25  				return fmt.Errorf("specifying \"%s=%s\" is not allowed", k, v)
    26  			}
    27  		}
    28  	}
    29  	return nil
    30  }
    31  
    32  // fieldsASCII is similar to strings.Fields but only allows ASCII whitespaces
    33  func fieldsASCII(s string) []string {
    34  	fn := func(r rune) bool {
    35  		switch r {
    36  		case '\t', '\n', '\f', '\r', ' ':
    37  			return true
    38  		}
    39  		return false
    40  	}
    41  	return strings.FieldsFunc(s, fn)
    42  }
    43  
    44  func parsePSOutput(output []byte, pids []int) (*types.ContainerProcessList, error) {
    45  	procList := &types.ContainerProcessList{}
    46  
    47  	lines := strings.Split(string(output), "\n")
    48  	procList.Titles = fieldsASCII(lines[0])
    49  
    50  	pidIndex := -1
    51  	for i, name := range procList.Titles {
    52  		if name == "PID" {
    53  			pidIndex = i
    54  		}
    55  	}
    56  	if pidIndex == -1 {
    57  		return nil, fmt.Errorf("Couldn't find PID field in ps output")
    58  	}
    59  
    60  	// loop through the output and extract the PID from each line
    61  	for _, line := range lines[1:] {
    62  		if len(line) == 0 {
    63  			continue
    64  		}
    65  		fields := fieldsASCII(line)
    66  		p, err := strconv.Atoi(fields[pidIndex])
    67  		if err != nil {
    68  			return nil, fmt.Errorf("Unexpected pid '%s': %s", fields[pidIndex], err)
    69  		}
    70  
    71  		for _, pid := range pids {
    72  			if pid == p {
    73  				// Make sure number of fields equals number of header titles
    74  				// merging "overhanging" fields
    75  				process := fields[:len(procList.Titles)-1]
    76  				process = append(process, strings.Join(fields[len(procList.Titles)-1:], " "))
    77  				procList.Processes = append(procList.Processes, process)
    78  			}
    79  		}
    80  	}
    81  	return procList, nil
    82  }
    83  
    84  // ContainerTop lists the processes running inside of the given
    85  // container by calling ps with the given args, or with the flags
    86  // "-ef" if no args are given.  An error is returned if the container
    87  // is not found, or is not running, or if there are any problems
    88  // running ps, or parsing the output.
    89  func (daemon *Daemon) ContainerTop(name string, psArgs string) (*types.ContainerProcessList, error) {
    90  	if psArgs == "" {
    91  		psArgs = "-ef"
    92  	}
    93  
    94  	if err := validatePSArgs(psArgs); err != nil {
    95  		return nil, err
    96  	}
    97  
    98  	container, err := daemon.GetContainer(name)
    99  	if err != nil {
   100  		return nil, err
   101  	}
   102  
   103  	if !container.IsRunning() {
   104  		return nil, errNotRunning{container.ID}
   105  	}
   106  
   107  	if container.IsRestarting() {
   108  		return nil, errContainerIsRestarting(container.ID)
   109  	}
   110  
   111  	pids, err := daemon.containerd.GetPidsForContainer(container.ID)
   112  	if err != nil {
   113  		return nil, err
   114  	}
   115  
   116  	output, err := exec.Command("ps", strings.Split(psArgs, " ")...).Output()
   117  	if err != nil {
   118  		return nil, fmt.Errorf("Error running ps: %v", err)
   119  	}
   120  	procList, err := parsePSOutput(output, pids)
   121  	if err != nil {
   122  		return nil, err
   123  	}
   124  	daemon.LogContainerEvent(container, "top")
   125  	return procList, nil
   126  }