1 /*
2 * Copyright (C) 2024 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 <memory>
18 #include <sys/sendfile.h>
19 #include <dirent.h>
20 #include <stdio.h>
21 #include <openssl/sha.h>
22 #include <fstream>
23 #include <sstream>
24
25 #include <android-base/file.h>
26 #include <android-base/logging.h>
27 #include <android-base/unique_fd.h>
28
29 #include "aconfigd_util.h"
30
31 using namespace android::base;
32
33 namespace android {
34 namespace aconfigd {
35
36 /// Remove all files in a dir
RemoveFilesInDir(const std::string & dir)37 Result<void> RemoveFilesInDir(const std::string& dir) {
38 auto dir_ptr = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(dir.c_str()), closedir);
39 if (!dir_ptr) {
40 return ErrnoError() << "failed to open dir " << dir;
41 }
42
43 struct dirent* entry;
44 while ((entry = readdir(dir_ptr.get())) != nullptr) {
45 if (entry->d_type != DT_REG) {
46 continue;
47 }
48 auto file = dir + "/" + entry->d_name;
49 if (unlink(file.c_str()) == -1) {
50 return ErrnoError() << "unlink() failed for " << file;
51 }
52 }
53
54 return {};
55 }
56
57 /// Copy file
CopyFile(const std::string & src,const std::string & dst,mode_t mode)58 Result<void> CopyFile(const std::string& src, const std::string& dst, mode_t mode) {
59 android::base::unique_fd src_fd(
60 TEMP_FAILURE_RETRY(open(src.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
61 if (src_fd == -1) {
62 return ErrnoError() << "open() failed for " << src;
63 }
64
65 if (FileExists(dst.c_str())) {
66 if (chmod(dst.c_str(), 0644) == -1) {
67 return ErrnoError() << "chmod() failed for " << dst;
68 }
69 }
70
71 android::base::unique_fd dst_fd(TEMP_FAILURE_RETRY(
72 open(dst.c_str(), O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0644)));
73 if (dst_fd == -1) {
74 return ErrnoError() << "open() failed for " << dst;
75 }
76
77 struct stat st;
78 if (fstat(src_fd.get(), &st) == -1) {
79 return ErrnoError() << "fstat() failed";
80 }
81 auto len = st.st_size;
82
83 if (sendfile(dst_fd, src_fd, nullptr, len) == -1) {
84 return ErrnoError() << "sendfile() failed";
85 }
86
87 if (chmod(dst.c_str(), mode) == -1) {
88 return ErrnoError() << "chmod() failed";
89 }
90
91 return {};
92 }
93
94 /// Get a file's timestamp in nano second
GetFileTimeStamp(const std::string & file)95 Result<uint64_t> GetFileTimeStamp(const std::string& file) {
96 struct stat st;
97 int result = stat(file.c_str(), &st);
98 if (result == -1) {
99 return ErrnoError() << "stat() failed";
100 }
101 uint64_t timestamp = st.st_mtim.tv_sec*1000000000 + st.st_mtim.tv_nsec;
102 return timestamp;
103 }
104
FileExists(const std::string & file)105 bool FileExists(const std::string& file) {
106 struct stat st;
107 return stat(file.c_str(), &st) == 0 ? true : false;
108 }
109
FileNonZeroSize(const std::string & file)110 bool FileNonZeroSize(const std::string& file) {
111 struct stat st;
112 return stat(file.c_str(), &st) == 0 ? st.st_size > 0 : false;
113 }
114
GetFilesDigest(const std::vector<std::string> & files)115 Result<std::string> GetFilesDigest(const std::vector<std::string>& files) {
116 SHA512_CTX ctx;
117 SHA512_Init(&ctx);
118
119 for (const auto& file : files) {
120 std::ifstream stream(file, std::ios::binary);
121 if (stream.bad()) {
122 return Error() << "Failed to open " << file;
123 }
124
125 char buf[1024];
126 while (!stream.eof()) {
127 stream.read(buf, 1024);
128 if (stream.bad()) {
129 return Error() << "Failed to read " << file;
130 }
131 int bytes_read = stream.gcount();
132 SHA512_Update(&ctx, buf, bytes_read);
133 }
134 }
135
136 uint8_t hash[SHA512_DIGEST_LENGTH];
137 SHA512_Final(hash, &ctx);
138 std::stringstream ss;
139 ss << std::hex;
140 for (int i = 0; i < SHA512_DIGEST_LENGTH; i++) {
141 ss << std::setw(2) << std::setfill('0') << static_cast<int>(hash[i]);
142 }
143 return ss.str();
144 }
145
146 } // namespace aconfig
147 } // namespace android
148