[process][darwin] Fix #670 remove call to common.Pipeline (prone to race condition)

Also properly parse lsof to get second txt record instead of hoping the 5th line is the right one (wrong data returned for pid 57)

internal/common/common.go

@@ -332,49 +332,6 @@ func HostRun(combineWith ...string) string {
 	return GetEnv("HOST_RUN", "/run", combineWith...)
 }
 
-// https://gist.github.com/kylelemons/1525278
-func Pipeline(cmds ...*exec.Cmd) ([]byte, []byte, error) {
-	// Require at least one command
-	if len(cmds) < 1 {
-		return nil, nil, nil
-	}
-
-	// Collect the output from the command(s)
-	var output bytes.Buffer
-	var stderr bytes.Buffer
-
-	last := len(cmds) - 1
-	for i, cmd := range cmds[:last] {
-		var err error
-		// Connect each command's stdin to the previous command's stdout
-		if cmds[i+1].Stdin, err = cmd.StdoutPipe(); err != nil {
-			return nil, nil, err
-		}
-		// Connect each command's stderr to a buffer
-		cmd.Stderr = &stderr
-	}
-
-	// Connect the output and error for the last command
-	cmds[last].Stdout, cmds[last].Stderr = &output, &stderr
-
-	// Start each command
-	for _, cmd := range cmds {
-		if err := cmd.Start(); err != nil {
-			return output.Bytes(), stderr.Bytes(), err
-		}
-	}
-
-	// Wait for each command to complete
-	for _, cmd := range cmds {
-		if err := cmd.Wait(); err != nil {
-			return output.Bytes(), stderr.Bytes(), err
-		}
-	}
-
-	// Return the pipeline output and the collected standard error
-	return output.Bytes(), stderr.Bytes(), nil
-}
-
 // getSysctrlEnv sets LC_ALL=C in a list of env vars for use when running
 // sysctl commands (see DoSysctrl).
 func getSysctrlEnv(env []string) []string {

internal/common/common_unix.go

@@ -23,7 +23,7 @@ func CallLsofWithContext(ctx context.Context, invoke Invoker, pid int32, args ..
 	}
 	out, err := invoke.CommandWithContext(ctx, lsof, cmd...)
 	if err != nil {
-		// if no pid found, lsof returnes code 1.
+		// if no pid found, lsof returns code 1.
 		if err.Error() == "exit status 1" && len(out) == 0 {
 			return []string{}, nil
 		}

process/process_darwin.go

@@ -108,30 +108,21 @@ func (p *Process) ExeWithContext(ctx context.Context) (string, error) {
 	if err != nil {
 		return "", err
 	}
-
-	awk_bin, err := exec.LookPath("awk")
+	out, err := invoke.CommandWithContext(ctx, lsof_bin, "-p", strconv.Itoa(int(p.Pid)), "-Fpfn")
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("bad call to lsof: %s", err)
 	}
-
-	sed_bin, err := exec.LookPath("sed")
-	if err != nil {
-		return "", err
+	txtFound := 0
+	lines := strings.Split(string(out), "\n")
+	for i := 1; i < len(lines); i += 2 {
+		if lines[i] == "ftxt" {
+			txtFound++
+			if txtFound == 2 {
+				return lines[i-1][1:], nil
 			}
-
-	lsof := exec.CommandContext(ctx, lsof_bin, "-p", strconv.Itoa(int(p.Pid)), "-Fpfn")
-	awk := exec.CommandContext(ctx, awk_bin, "NR==5{print}")
-	sed := exec.CommandContext(ctx, sed_bin, "s/n\\//\\//")
-
-	output, _, err := common.Pipeline(lsof, awk, sed)
-
-	if err != nil {
-		return "", err
 		}
-
-	ret := strings.TrimSpace(string(output))
-
-	return ret, nil
+	}
+	return "", fmt.Errorf("missing txt data returned by lsof")
 }
 
 // Cmdline returns the command line arguments of the process as a string with