core: remove unused kernel module helpers

kmod.go was entirely dead: IsBuiltinKernelModule, LoadKernelModule,
CheckKernelModuleParam, and the getKernelVersion helper had no callers
anywhere in the repo (verified with grep, deadcode, and staticcheck).
Remove the file.

Signed-off-by: Joshua Hoblitt <josh@hoblitt.com>

pkg/util/sys/kmod.go

@@ -1,76 +0,0 @@
-/*
-Copyright 2016 The Rook Authors. All rights reserved.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-	http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-package sys
-
-import (
-	"fmt"
-	"os/exec"
-	"strings"
-
-	pkgexec "github.com/rook/rook/pkg/util/exec"
-)
-
-func getKernelVersion() (string, error) {
-	var output []byte
-	cmd := exec.Command("uname", "-r")
-	output, err := cmd.Output()
-	out := strings.TrimSpace(string(output))
-	if err != nil {
-		return out, err
-	}
-
-	return out, nil
-}
-
-func IsBuiltinKernelModule(name string, executor pkgexec.Executor) (bool, error) {
-	kv, err := getKernelVersion()
-	if err != nil {
-		return false, fmt.Errorf("failed to get kernel version: %+v", err)
-	}
-
-	kv = fmt.Sprintf("/lib/modules/%s/modules.builtin", kv)
-	out, err := executor.ExecuteCommandWithCombinedOutput("cat", kv)
-	if err != nil {
-		return false, fmt.Errorf("failed to cat %s: %+v", kv, err)
-	}
-
-	result := Grep(out, name)
-	return result != "", nil
-}
-
-func LoadKernelModule(name string, options []string, executor pkgexec.Executor) error {
-	if options == nil {
-		options = []string{}
-	}
-
-	args := append([]string{name}, options...)
-
-	if err := executor.ExecuteCommand("modprobe", args[:]...); err != nil {
-		return fmt.Errorf("failed to load kernel module %s: %+v", name, err)
-	}
-
-	return nil
-}
-
-func CheckKernelModuleParam(name, param string, executor pkgexec.Executor) (bool, error) {
-	out, err := executor.ExecuteCommandWithOutput("modinfo", "-F", "parm", name)
-	if err != nil {
-		return false, fmt.Errorf("failed to check for %s module %s param: %+v", name, param, err)
-	}
-
-	result := Grep(out, fmt.Sprintf("^%s", param))
-	return result != "", nil
-}