github.com/david-imola/snapd@v0.0.0-20210611180407-2de8ddeece6d/overlord/snapstate/policy/gadget.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2019 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package policy
    21  
    22  import (
    23  	"github.com/snapcore/snapd/boot"
    24  	"github.com/snapcore/snapd/overlord/snapstate"
    25  	"github.com/snapcore/snapd/overlord/state"
    26  	"github.com/snapcore/snapd/snap"
    27  )
    28  
    29  type gadgetPolicy struct {
    30  	modelGadget string
    31  }
    32  
    33  func (p *gadgetPolicy) CanRemove(st *state.State, snapst *snapstate.SnapState, rev snap.Revision, dev boot.Device) error {
    34  	name := snapst.InstanceName()
    35  	if name == "" {
    36  		// not installed, or something. What are you even trying to do.
    37  		return errNoName
    38  	}
    39  
    40  	if ephemeral(dev) {
    41  		return errEphemeralSnapsNotRemovalable
    42  	}
    43  
    44  	if p.modelGadget != name {
    45  		return nil
    46  	}
    47  
    48  	if !rev.Unset() {
    49  		return nil
    50  	}
    51  
    52  	return errIsModel
    53  }