1//
2// Copyright (C) 2015 The Android Open Source Project
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8//      http://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15//
16
17#include "update_engine/boot_control_android.h"
18
19#include <base/bind.h>
20#include <base/files/file_util.h>
21#include <base/logging.h>
22#include <base/strings/string_util.h>
23#include <brillo/make_unique_ptr.h>
24#include <brillo/message_loops/message_loop.h>
25#include <cutils/properties.h>
26#include <fs_mgr.h>
27
28#include "update_engine/common/utils.h"
29
30using std::string;
31
32namespace {
33
34// Open the appropriate fstab file and fallback to /fstab.device if
35// that's what's being used.
36static struct fstab* OpenFSTab() {
37  char propbuf[PROPERTY_VALUE_MAX];
38  struct fstab* fstab;
39
40  property_get("ro.hardware", propbuf, "");
41  string fstab_name = string("/fstab.") + propbuf;
42  fstab = fs_mgr_read_fstab(fstab_name.c_str());
43  if (fstab != nullptr)
44    return fstab;
45
46  fstab = fs_mgr_read_fstab("/fstab.device");
47  return fstab;
48}
49
50}  // namespace
51
52
53namespace chromeos_update_engine {
54
55namespace boot_control {
56
57// Factory defined in boot_control.h.
58std::unique_ptr<BootControlInterface> CreateBootControl() {
59  std::unique_ptr<BootControlAndroid> boot_control(new BootControlAndroid());
60  if (!boot_control->Init()) {
61    return nullptr;
62  }
63  return brillo::make_unique_ptr(boot_control.release());
64}
65
66}  // namespace boot_control
67
68bool BootControlAndroid::Init() {
69  const hw_module_t* hw_module;
70  int ret;
71
72  ret = hw_get_module(BOOT_CONTROL_HARDWARE_MODULE_ID, &hw_module);
73  if (ret != 0) {
74    LOG(ERROR) << "Error loading boot_control HAL implementation.";
75    return false;
76  }
77
78  module_ = reinterpret_cast<boot_control_module_t*>(const_cast<hw_module_t*>(hw_module));
79  module_->init(module_);
80
81  LOG(INFO) << "Loaded boot_control HAL "
82            << "'" << hw_module->name << "' "
83            << "version " << (hw_module->module_api_version>>8) << "."
84            << (hw_module->module_api_version&0xff) << " "
85            << "authored by '" << hw_module->author << "'.";
86  return true;
87}
88
89unsigned int BootControlAndroid::GetNumSlots() const {
90  return module_->getNumberSlots(module_);
91}
92
93BootControlInterface::Slot BootControlAndroid::GetCurrentSlot() const {
94  return module_->getCurrentSlot(module_);
95}
96
97bool BootControlAndroid::GetPartitionDevice(const string& partition_name,
98                                            Slot slot,
99                                            string* device) const {
100  struct fstab* fstab;
101  struct fstab_rec* record;
102
103  // We can't use fs_mgr to look up |partition_name| because fstab
104  // doesn't list every slot partition (it uses the slotselect option
105  // to mask the suffix).
106  //
107  // We can however assume that there's an entry for the /misc mount
108  // point and use that to get the device file for the misc
109  // partition. This helps us locate the disk that |partition_name|
110  // resides on. From there we'll assume that a by-name scheme is used
111  // so we can just replace the trailing "misc" by the given
112  // |partition_name| and suffix corresponding to |slot|, e.g.
113  //
114  //   /dev/block/platform/soc.0/7824900.sdhci/by-name/misc ->
115  //   /dev/block/platform/soc.0/7824900.sdhci/by-name/boot_a
116  //
117  // If needed, it's possible to relax the by-name assumption in the
118  // future by trawling /sys/block looking for the appropriate sibling
119  // of misc and then finding an entry in /dev matching the sysfs
120  // entry.
121
122  fstab = OpenFSTab();
123  if (fstab == nullptr) {
124    LOG(ERROR) << "Error opening fstab file.";
125    return false;
126  }
127  record = fs_mgr_get_entry_for_mount_point(fstab, "/misc");
128  if (record == nullptr) {
129    LOG(ERROR) << "Error finding /misc entry in fstab file.";
130    fs_mgr_free_fstab(fstab);
131    return false;
132  }
133
134  base::FilePath misc_device = base::FilePath(record->blk_device);
135  fs_mgr_free_fstab(fstab);
136
137  if (!utils::IsSymlink(misc_device.value().c_str())) {
138    LOG(ERROR) << "Device file " << misc_device.value() << " for /misc "
139               << "is not a symlink.";
140    return false;
141  }
142
143  const char* suffix = module_->getSuffix(module_, slot);
144  if (suffix == nullptr) {
145    LOG(ERROR) << "boot_control impl returned no suffix for slot "
146               << SlotName(slot);
147    return false;
148  }
149
150  base::FilePath path = misc_device.DirName().Append(partition_name + suffix);
151  if (!base::PathExists(path)) {
152    LOG(ERROR) << "Device file " << path.value() << " does not exist.";
153    return false;
154  }
155
156  *device = path.value();
157  return true;
158}
159
160bool BootControlAndroid::IsSlotBootable(Slot slot) const {
161  int ret = module_->isSlotBootable(module_, slot);
162  if (ret < 0) {
163    LOG(ERROR) << "Unable to determine if slot " << SlotName(slot)
164               << " is bootable: " << strerror(-ret);
165    return false;
166  }
167  return ret == 1;
168}
169
170bool BootControlAndroid::MarkSlotUnbootable(Slot slot) {
171  int ret = module_->setSlotAsUnbootable(module_, slot);
172  if (ret < 0) {
173    LOG(ERROR) << "Unable to mark slot " << SlotName(slot)
174               << " as bootable: " << strerror(-ret);
175    return false;
176  }
177  return ret == 0;
178}
179
180bool BootControlAndroid::SetActiveBootSlot(Slot slot) {
181  int ret = module_->setActiveBootSlot(module_, slot);
182  if (ret < 0) {
183    LOG(ERROR) << "Unable to set the active slot to slot " << SlotName(slot)
184               << ": " << strerror(-ret);
185  }
186  return ret == 0;
187}
188
189bool BootControlAndroid::MarkBootSuccessfulAsync(
190    base::Callback<void(bool)> callback) {
191  int ret = module_->markBootSuccessful(module_);
192  if (ret < 0) {
193    LOG(ERROR) << "Unable to mark boot successful: " << strerror(-ret);
194  }
195  return brillo::MessageLoop::current()->PostTask(
196             FROM_HERE, base::Bind(callback, ret == 0)) !=
197         brillo::MessageLoop::kTaskIdNull;
198}
199
200}  // namespace chromeos_update_engine
201