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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2022 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package ctlcmd
import (
"errors"
"fmt"
"github.com/snapcore/snapd/i18n"
"github.com/snapcore/snapd/interfaces"
"github.com/snapcore/snapd/osutil/kmod"
"github.com/snapcore/snapd/overlord/hookstate"
"github.com/snapcore/snapd/overlord/ifacestate"
)
var (
shortKmodHelp = i18n.G("Load or unload kernel modules")
longKmodHelp = i18n.G(`
The kmod command handles loading and unloading of kernel modules.`)
kmodLoadModule = kmod.LoadModule
kmodUnloadModule = kmod.UnloadModule
)
func init() {
addCommand("kmod", shortKmodHelp, longKmodHelp, func() command {
cmd := &kmodCommand{}
cmd.InsertCmd.kmod = cmd
cmd.RemoveCmd.kmod = cmd
return cmd
})
}
func (m *kmodCommand) Execute([]string) error {
// This is needed in order to implement the interface, but it's never
// called.
return nil
}
type kmodCommand struct {
baseCommand
InsertCmd KModInsertCmd `command:"insert" description:"load a kernel module"`
RemoveCmd KModRemoveCmd `command:"remove" description:"unload a kernel module"`
}
type KModInsertCmd struct {
Positional struct {
Module string `positional-arg-name:"<module>" required:"yes" description:"kernel module name"`
Options []string `positional-arg-name:"<options>" description:"kernel module options"`
} `positional-args:"yes" required:"yes"`
kmod *kmodCommand
}
func (k *KModInsertCmd) Execute([]string) error {
context, err := k.kmod.ensureContext()
if err != nil {
return err
}
if err := kmodCheckConnection(context, k.Positional.Module, k.Positional.Options); err != nil {
return fmt.Errorf("cannot load module %q: %v", k.Positional.Module, err)
}
if err := kmodLoadModule(k.Positional.Module, k.Positional.Options); err != nil {
return fmt.Errorf("cannot load module %q: %v", k.Positional.Module, err)
}
return nil
}
type KModRemoveCmd struct {
Positional struct {
Module string `positional-arg-name:"<module>" required:"yes" description:"kernel module name"`
} `positional-args:"yes" required:"yes"`
kmod *kmodCommand
}
func (k *KModRemoveCmd) Execute([]string) error {
context, err := k.kmod.ensureContext()
if err != nil {
return err
}
if err := kmodCheckConnection(context, k.Positional.Module, []string{}); err != nil {
return fmt.Errorf("cannot unload module %q: %v", k.Positional.Module, err)
}
if err := kmodUnloadModule(k.Positional.Module); err != nil {
return fmt.Errorf("cannot unload module %q: %v", k.Positional.Module, err)
}
return nil
}
// kmodMatchConnection checks whether the given kmod connection attributes give
// the snap permission to execute the kmod command
func kmodMatchConnection(attributes map[string]any, moduleName string, moduleOptions []string) bool {
load, found := attributes["load"]
if !found || load.(string) != "dynamic" {
return false
}
if moduleName != attributes["name"].(string) {
return false
}
if len(moduleOptions) > 0 {
// snapctl can be invoked with options only if the "options" attribute
// on the plug is set to "*"
optionsAttr, ok := attributes["options"]
if !ok || optionsAttr.(string) != "*" {
return false
}
}
return true
}
// kmodCheckConnection walks through the established connections to find one which
// is compatible with a kmod operation on the given moduleName and
// moduleOptions. Returns an error if not found.
var kmodCheckConnection = func(context *hookstate.Context, moduleName string, moduleOptions []string) (err error) {
snapName := context.InstanceName()
st := context.State()
st.Lock()
defer st.Unlock()
conns, err := ifacestate.ConnectionStates(st)
if err != nil {
return fmt.Errorf("internal error: cannot get connections: %s", err)
}
for connId, connState := range conns {
if connState.Interface != "kernel-module-load" {
continue
}
if !connState.Active() {
continue
}
connRef, err := interfaces.ParseConnRef(connId)
if err != nil {
return err
}
if connRef.PlugRef.Snap != snapName {
continue
}
modules, ok := connState.StaticPlugAttrs["modules"].([]any)
if !ok {
continue
}
for _, moduleAttributes := range modules {
attributes := moduleAttributes.(map[string]any)
if kmodMatchConnection(attributes, moduleName, moduleOptions) {
return nil
}
}
}
return errors.New("required interface not connected")
}
|
