SUSE/saptune

package system

import (
    "fmt"
    "os/exec"
    "strings"
)

// GetCurrentLogins returns the user ids of the currently logged in users
func GetCurrentLogins() []string {
    uID := []string{}
    cmdName := "/usr/bin/loginctl"
    cmdArgs := []string{"--no-pager", "--no-legend", "--no-ask-password", "list-users"}
    if !CmdIsAvailable(cmdName) {
        WarningLog("command '%s' not found", cmdName)
        return uID
    }
    running, err := IsSystemRunning()
    if err != nil {
        ErrorLog("%v - Failed to call command systemctl", err)
        return uID
    }
    if running {
        cmdOut, err := exec.Command(cmdName, cmdArgs...).CombinedOutput()
        if err != nil {
            WarningLog("failed to invoke external command '%s %v': %v, output: %s", cmdName, cmdArgs, err, string(cmdOut))
            return uID
        }
        for _, logins := range strings.Split(string(cmdOut), "\n") {
            if logins == "" {
                continue
            }
            user := strings.Split(strings.TrimSpace(logins), " ")
            uID = append(uID, user[0])
        }
    }
    return uID
}

// GetTasksMax returns the current limit of TasksMax for a given user id
// which is the value for UserTasksMax
func GetTasksMax(userID string) string {
    //systemctl show -p TasksMax user-<uid>.slice
    uSlice := "user-" + userID + ".slice"
    cmdName := "/usr/bin/systemctl"
    cmdArgs := []string{"show", "-p", "TasksMax", uSlice}
    DebugLog("GetTasksMax - calling '%s' with '%s' args", cmdName, strings.Join(cmdArgs, " "))

    if !CmdIsAvailable(cmdName) {
        WarningLog("command '%s' not found", cmdName)
        return ""
    }
    cmdOut, err := exec.Command(cmdName, cmdArgs...).CombinedOutput()
    if err != nil {
        WarningLog("failed to invoke external command '%s %v': %v, output: %s", cmdName, cmdArgs, err, string(cmdOut))
        return ""
    }
    tasksMax := strings.Split(strings.TrimSpace(string(cmdOut)), "=")
    DebugLog("GetTasksMax - cmd returns '%+v'", tasksMax)
    // The result of strings.Split of an 'empty' string is a slice with
    // one element - the empty string.
    if len(tasksMax) == 1 && tasksMax[0] == "" {
        return tasksMax[0]
    }
    return tasksMax[1]
}

// SetTasksMax sets the limit of TasksMax for a given user id to 'limit'
func SetTasksMax(userID, limit string) error {
    //systemctl  --runtime set-property user-<uid>.slice TasksMax=infinity
    uSlice := "user-" + userID + ".slice"
    tmLimit := "TasksMax=" + limit
    cmdName := "/usr/bin/systemctl"
    cmdArgs := []string{"--runtime", "set-property", uSlice, tmLimit}

    if !CmdIsAvailable(cmdName) {
        return fmt.Errorf("command '%s' not found", cmdName)
    }
    _, err := exec.Command(cmdName, cmdArgs...).CombinedOutput()
    return err
}