1 /*
2 * Copyright (C) 2016 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 <iostream>
18
19 #include <android-base/logging.h>
20 #include <android-base/strings.h>
21
22 #ifndef LOG_TAG
23 #define LOG_TAG "preopt2cachename"
24 #endif
25
26 static const char* kDalvikCacheDir = "/data/dalvik-cache/";
27 static const char* kOdexCacheSuffix = "@classes.dex";
28 static const char* kVdexCacheSuffix = "@classes.vdex";
29 static const char* kArtCacheSuffix = "@classes.art";
30
31 // Returns the ISA extracted from the file_location. file_location is formatted like
32 // /system{/product,}/{priv-,}app/<app_name>/oat/<isa>/<app_name>.{odex,vdex} for all functions. We
33 // return an empty string "" in error cases.
ExtractISA(const std::string & file_location)34 static std::string ExtractISA(const std::string& file_location) {
35 std::vector<std::string> split_file_location = android::base::Split(file_location, "/");
36 if (split_file_location.size() <= 1) {
37 return "";
38 } else if (split_file_location.size() != 7 && split_file_location.size() != 8) {
39 LOG(WARNING) << "Unexpected length for file-location. We expected 7 or 8 segments but found "
40 << split_file_location.size() << " for " << file_location;
41 }
42 return split_file_location[split_file_location.size() - 2];
43 }
44
45 // Returns the apk name extracted from the file_location.
46 // file_location is formatted like /system/app/<app_name>/oat/<isa>/<app_name>.{odex,vdex}.
47 // We return the final <app_name> with the .{odex,vdex} replaced with .apk.
ExtractAPKName(const std::string & file_location)48 static std::string ExtractAPKName(const std::string& file_location) {
49 // Find and copy filename.
50 size_t file_location_start = file_location.rfind('/');
51 if (file_location_start == std::string::npos) {
52 return "";
53 }
54 size_t ext_start = file_location.rfind('.');
55 if (ext_start == std::string::npos || ext_start < file_location_start) {
56 return "";
57 }
58 std::string apk_name = file_location.substr(file_location_start + 1,
59 ext_start - file_location_start);
60
61 // Replace extension with .apk.
62 apk_name += "apk";
63 return apk_name;
64 }
65
66 // The cache file name is /data/dalvik-cache/<isa>/ prior to this function
SystemBFilenameToCacheFile(const std::string & file_location,std::string & cache_file)67 static bool SystemBFilenameToCacheFile(const std::string& file_location,
68 /*in-out*/std::string& cache_file) {
69 // Skip the first '/' in file_location.
70 size_t initial_position = file_location[0] == '/' ? 1 : 0;
71 size_t apk_position = file_location.find("/oat", initial_position);
72 if (apk_position == std::string::npos) {
73 LOG(ERROR) << "Unable to find oat directory!";
74 return false;
75 }
76
77 size_t cache_file_position = cache_file.size();
78 cache_file += file_location.substr(initial_position, apk_position);
79 // '/' -> '@' up to where the apk would be.
80 cache_file_position = cache_file.find('/', cache_file_position);
81 while (cache_file_position != std::string::npos) {
82 cache_file[cache_file_position] = '@';
83 cache_file_position = cache_file.find('/', cache_file_position);
84 }
85
86 // Add <apk_name>.
87 std::string apk_name = ExtractAPKName(file_location);
88 if (apk_name.empty()) {
89 LOG(ERROR) << "Unable to determine apk name from file name '" << file_location << "'";
90 return false;
91 }
92 std::string::size_type pos = file_location.find_last_of('.');
93 if (pos == std::string::npos) {
94 LOG(ERROR) << "Invalid file location '" << file_location << "'";
95 return false;
96 }
97 cache_file += apk_name;
98 std::string extension(file_location.substr(pos));
99 if (extension == ".vdex") {
100 cache_file += kVdexCacheSuffix;
101 } else if (extension == ".art") {
102 cache_file += kArtCacheSuffix;
103 } else {
104 cache_file += kOdexCacheSuffix;
105 }
106 return true;
107 }
108
109 // Do the overall transformation from file_location to output_file_location. Prior to this the
110 // output_file_location is empty.
SystemBFileToCacheFile(const std::string & file_location,std::string & output_file_location)111 static bool SystemBFileToCacheFile(const std::string& file_location,
112 /*out*/std::string& output_file_location) {
113 std::string isa = ExtractISA(file_location);
114 if (isa.empty()) {
115 LOG(ERROR) << "Unable to determine isa for file '" << file_location << "', skipping";
116 return false;
117 }
118 output_file_location += isa;
119 output_file_location += '/';
120 return SystemBFilenameToCacheFile(file_location, output_file_location);
121 }
122
123 // This program is used to determine where in the /data directory the runtime will search for an
124 // odex file if it is unable to find one at the given 'preopt-name' location. This is used to allow
125 // us to store these preopted files in the unused system_b partition and copy them out on first
126 // boot of the device.
main(int argc,char * argv[])127 int main(int argc, char *argv[]) {
128 if (argc != 2) {
129 LOG(ERROR) << "usage: preopt2cachename preopt-location";
130 return 2;
131 }
132 std::string file_location(argv[1]);
133 std::string output_file_location(kDalvikCacheDir);
134 if (!SystemBFileToCacheFile(file_location, output_file_location)) {
135 return 1;
136 } else {
137 std::cout << output_file_location;
138 }
139 return 0;
140 }
141