firehol/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package fail2ban

import (
    "context"
    "errors"
    "fmt"
    "os"
    "os/exec"
    "strings"
    "time"

    "github.com/netdata/netdata/go/plugins/logger"
)

var errJailNotExist = errors.New("jail not exist")

const socketPathInDocker = "/host/var/run/fail2ban/fail2ban.sock"

func newFail2BanClientCliExec(ndsudoPath string, timeout time.Duration, log *logger.Logger) *fail2banClientCliExec {
    _, err := os.Stat("/host/var/run")

    return &fail2banClientCliExec{
        Logger:         log,
        ndsudoPath:     ndsudoPath,
        timeout:        timeout,
        isInsideDocker: err == nil,
    }
}

type fail2banClientCliExec struct {
    *logger.Logger

    ndsudoPath     string
    timeout        time.Duration
    isInsideDocker bool
}

func (e *fail2banClientCliExec) status() ([]byte, error) {
    if e.isInsideDocker {
        return e.execute("fail2ban-client-status-socket",
            "--socket_path", socketPathInDocker,
        )
    }
    return e.execute("fail2ban-client-status")
}

func (e *fail2banClientCliExec) jailStatus(jail string) ([]byte, error) {
    if e.isInsideDocker {
        return e.execute("fail2ban-client-status-jail-socket",
            "--jail", jail,
            "--socket_path", socketPathInDocker,
        )
    }
    return e.execute("fail2ban-client-status-jail",
        "--jail", jail,
    )
}

func (e *fail2banClientCliExec) execute(args ...string) ([]byte, error) {
    ctx, cancel := context.WithTimeout(context.Background(), e.timeout)
    defer cancel()

    cmd := exec.CommandContext(ctx, e.ndsudoPath, args...)
    e.Debugf("executing '%s'", cmd)

    bs, err := cmd.Output()
    if err != nil {
        if strings.HasPrefix(strings.TrimSpace(string(bs)), "Sorry but the jail") {
            return nil, errJailNotExist
        }
        return nil, fmt.Errorf("error on '%s': %v", cmd, err)
    }

    return bs, nil
}