github.com/rigado/snapd@v2.42.5-go-mod+incompatible/boot/kernel_os.go (about) 1 // -*- Mode: Go; indent-tabs-mode: t -*- 2 3 /* 4 * Copyright (C) 2014-2015 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 boot 21 22 import ( 23 "fmt" 24 "path/filepath" 25 26 "github.com/snapcore/snapd/bootloader" 27 "github.com/snapcore/snapd/logger" 28 "github.com/snapcore/snapd/snap" 29 ) 30 31 type coreBootParticipant struct { 32 s snap.PlaceInfo 33 t snap.Type 34 } 35 36 // ensure coreBootParticipant is a BootParticipant 37 var _ BootParticipant = (*coreBootParticipant)(nil) 38 39 func (*coreBootParticipant) IsTrivial() bool { return false } 40 41 func (bs *coreBootParticipant) SetNextBoot() error { 42 bootloader, err := bootloader.Find("", nil) 43 if err != nil { 44 return fmt.Errorf("cannot set next boot: %s", err) 45 } 46 47 var nextBoot, goodBoot string 48 switch bs.t { 49 case snap.TypeOS, snap.TypeBase: 50 nextBoot = "snap_try_core" 51 goodBoot = "snap_core" 52 case snap.TypeKernel: 53 nextBoot = "snap_try_kernel" 54 goodBoot = "snap_kernel" 55 } 56 blobName := filepath.Base(bs.s.MountFile()) 57 58 // check if we actually need to do anything, i.e. the exact same 59 // kernel/core revision got installed again (e.g. firstboot) 60 // and we are not in any special boot mode 61 m, err := bootloader.GetBootVars("snap_mode", goodBoot) 62 if err != nil { 63 return fmt.Errorf("cannot set next boot: %s", err) 64 } 65 if m[goodBoot] == blobName { 66 // If we were in anything but default ("") mode before 67 // and now switch to the good core/kernel again, make 68 // sure to clean the snap_mode here. This also 69 // mitigates https://forum.snapcraft.io/t/5253 70 if m["snap_mode"] != "" { 71 return bootloader.SetBootVars(map[string]string{ 72 "snap_mode": "", 73 nextBoot: "", 74 }) 75 } 76 return nil 77 } 78 79 return bootloader.SetBootVars(map[string]string{ 80 nextBoot: blobName, 81 "snap_mode": "try", 82 }) 83 } 84 85 func (bs *coreBootParticipant) ChangeRequiresReboot() bool { 86 bootloader, err := bootloader.Find("", nil) 87 if err != nil { 88 logger.Noticef("cannot get boot settings: %s", err) 89 return false 90 } 91 92 var nextBoot, goodBoot string 93 switch bs.t { 94 case snap.TypeKernel: 95 nextBoot = "snap_try_kernel" 96 goodBoot = "snap_kernel" 97 case snap.TypeOS, snap.TypeBase: 98 nextBoot = "snap_try_core" 99 goodBoot = "snap_core" 100 } 101 102 m, err := bootloader.GetBootVars(nextBoot, goodBoot) 103 if err != nil { 104 logger.Noticef("cannot get boot variables: %s", err) 105 return false 106 } 107 108 squashfsName := filepath.Base(bs.s.MountFile()) 109 if m[nextBoot] == squashfsName && m[goodBoot] != m[nextBoot] { 110 return true 111 } 112 113 return false 114 } 115 116 type coreKernel struct { 117 s snap.PlaceInfo 118 } 119 120 // ensure coreKernel is a Kernel 121 var _ BootKernel = (*coreKernel)(nil) 122 123 func (*coreKernel) IsTrivial() bool { return false } 124 125 func (k *coreKernel) RemoveKernelAssets() error { 126 // XXX: shouldn't we check the snap type? 127 bootloader, err := bootloader.Find("", nil) 128 if err != nil { 129 return fmt.Errorf("cannot remove kernel assets: %s", err) 130 } 131 132 // ask bootloader to remove the kernel assets if needed 133 return bootloader.RemoveKernelAssets(k.s) 134 } 135 136 func (k *coreKernel) ExtractKernelAssets(snapf snap.Container) error { 137 bootloader, err := bootloader.Find("", nil) 138 if err != nil { 139 return fmt.Errorf("cannot extract kernel assets: %s", err) 140 } 141 142 // ask bootloader to extract the kernel assets if needed 143 return bootloader.ExtractKernelAssets(k.s, snapf) 144 }