1 /*
2 * Copyright (C) 2021 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 "checkpoint_handling.h"
18 #include "log.h"
19
20 #include <fstab/fstab.h>
21 #include <cstring>
22 #include <string>
23
24 namespace {
25
26 bool checkpointingDoneForever = false;
27
28 } // namespace
29
is_data_checkpoint_active(bool * active)30 int is_data_checkpoint_active(bool* active) {
31 if (!active) {
32 ALOGE("active out parameter is null");
33 return 0;
34 }
35
36 *active = false;
37
38 if (checkpointingDoneForever) {
39 return 0;
40 }
41
42 android::fs_mgr::Fstab procMounts;
43 bool success = android::fs_mgr::ReadFstabFromFile("/proc/mounts", &procMounts);
44 if (!success) {
45 ALOGE("Could not parse /proc/mounts\n");
46 /* Really bad. Tell the caller to abort the write. */
47 return -1;
48 }
49
50 android::fs_mgr::FstabEntry* dataEntry =
51 android::fs_mgr::GetEntryForMountPoint(&procMounts, "/data");
52 if (dataEntry == NULL) {
53 ALOGE("/data is not mounted yet\n");
54 return 0;
55 }
56
57 /* We can't handle e.g., ext4. Nothing we can do about it for now. */
58 if (dataEntry->fs_type != "f2fs") {
59 ALOGW("Checkpoint status not supported for filesystem %s\n", dataEntry->fs_type.c_str());
60 checkpointingDoneForever = true;
61 return 0;
62 }
63
64 /*
65 * The data entry looks like "... blah,checkpoint=disable:0,blah ...".
66 * checkpoint=disable means checkpointing is on (yes, arguably reversed).
67 */
68 size_t checkpointPos = dataEntry->fs_options.find("checkpoint=disable");
69 if (checkpointPos == std::string::npos) {
70 /* Assumption is that once checkpointing turns off, it stays off */
71 checkpointingDoneForever = true;
72 } else {
73 *active = true;
74 }
75
76 return 0;
77 }
78