1 //
2 // Copyright (C) 2019 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 "libgsi/libgsi.h"
18
19 #include <string.h>
20 #include <unistd.h>
21
22 #include <string>
23
24 #include <android-base/file.h>
25 #include <android-base/parseint.h>
26 #include <android-base/unique_fd.h>
27
28 #include "file_paths.h"
29 #include "libgsi_private.h"
30
31 namespace android {
32 namespace gsi {
33
34 using namespace std::literals;
35 using android::base::unique_fd;
36
IsGsiRunning()37 bool IsGsiRunning() {
38 return !access(kGsiBootedIndicatorFile, F_OK);
39 }
40
IsGsiInstalled()41 bool IsGsiInstalled() {
42 return !access(kGsiInstallStatusFile, F_OK);
43 }
44
WriteAndSyncFile(const std::string & data,const std::string & file)45 static bool WriteAndSyncFile(const std::string& data, const std::string& file) {
46 unique_fd fd(open(file.c_str(), O_WRONLY | O_NOFOLLOW | O_CLOEXEC));
47 if (fd < 0) {
48 return false;
49 }
50 if (!android::base::WriteFully(fd, data.c_str(), data.size())) {
51 return false;
52 }
53 return fsync(fd) == 0;
54 }
55
CanBootIntoGsi(std::string * error)56 static bool CanBootIntoGsi(std::string* error) {
57 if (!IsGsiInstalled()) {
58 *error = "not detected";
59 return false;
60 }
61
62 std::string boot_key;
63 if (!GetInstallStatus(&boot_key)) {
64 *error = "error ("s + strerror(errno) + ")";
65 return false;
66 }
67
68 // Give up if we've failed to boot kMaxBootAttempts times.
69 int attempts;
70 if (GetBootAttempts(boot_key, &attempts)) {
71 if (attempts + 1 > kMaxBootAttempts) {
72 *error = "exceeded max boot attempts";
73 return false;
74 }
75
76 std::string new_key;
77 if (!access(kGsiOneShotBootFile, F_OK)) {
78 // Mark the GSI as disabled. This only affects the next boot, not
79 // the current boot. Note that we leave the one_shot status behind.
80 // This is so IGsiService can still return GSI_STATE_SINGLE_BOOT
81 // while the GSI is running.
82 new_key = kInstallStatusDisabled;
83 } else {
84 new_key = std::to_string(attempts + 1);
85 }
86 if (!WriteAndSyncFile(new_key, kGsiInstallStatusFile)) {
87 *error = "error ("s + strerror(errno) + ")";
88 return false;
89 }
90 return true;
91 }
92
93 if (boot_key != kInstallStatusOk) {
94 *error = "not enabled";
95 return false;
96 }
97 return true;
98 }
99
CanBootIntoGsi(std::string * metadata_file,std::string * error)100 bool CanBootIntoGsi(std::string* metadata_file, std::string* error) {
101 // Always delete this as a safety precaution, so we can return to the
102 // original system image. If we're confident GSI will boot, this will
103 // get re-created by MarkSystemAsGsi.
104 android::base::RemoveFileIfExists(kGsiBootedIndicatorFile);
105
106 if (!CanBootIntoGsi(error)) {
107 return false;
108 }
109
110 *metadata_file = kGsiLpMetadataFile;
111 return true;
112 }
113
UninstallGsi()114 bool UninstallGsi() {
115 return android::base::WriteStringToFile(kInstallStatusWipe, kGsiInstallStatusFile);
116 }
117
DisableGsi()118 bool DisableGsi() {
119 return android::base::WriteStringToFile(kInstallStatusDisabled, kGsiInstallStatusFile);
120 }
121
MarkSystemAsGsi()122 bool MarkSystemAsGsi() {
123 return android::base::WriteStringToFile("1", kGsiBootedIndicatorFile);
124 }
125
GetInstallStatus(std::string * status)126 bool GetInstallStatus(std::string* status) {
127 return android::base::ReadFileToString(kGsiInstallStatusFile, status);
128 }
129
GetBootAttempts(const std::string & boot_key,int * attempts)130 bool GetBootAttempts(const std::string& boot_key, int* attempts) {
131 return android::base::ParseInt(boot_key, attempts);
132 }
133
134 } // namespace gsi
135 } // namespace android
136