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 "odr_fs_utils.h"
18
19 #include <dirent.h>
20 #include <ftw.h>
21 #include <string.h>
22 #include <sys/stat.h>
23 #include <sys/statvfs.h>
24 #include <unistd.h>
25
26 #include <iosfwd>
27 #include <memory>
28 #include <ostream>
29 #include <queue>
30 #include <string>
31 #include <string_view>
32 #include <type_traits>
33 #include <vector>
34
35 #include <android-base/logging.h>
36 #include <android-base/macros.h>
37 #include <android-base/strings.h>
38 #include <base/os.h>
39
40 namespace art {
41 namespace odrefresh {
42
43 // Callback for use with nftw(3) to assist with clearing files and sub-directories.
44 // This method removes files and directories below the top-level directory passed to nftw().
NftwCleanUpCallback(const char * fpath,const struct stat * sb,int typeflag,struct FTW * ftwbuf)45 static int NftwCleanUpCallback(const char* fpath,
46 [[maybe_unused]] const struct stat* sb,
47 int typeflag,
48 struct FTW* ftwbuf) {
49 switch (typeflag) {
50 case FTW_F:
51 return unlink(fpath);
52 case FTW_DP:
53 return (ftwbuf->level == 0) ? 0 : rmdir(fpath);
54 default:
55 return -1;
56 }
57 }
58
RemoveDirectory(const std::string & dir_path)59 WARN_UNUSED bool RemoveDirectory(const std::string& dir_path) {
60 if (!OS::DirectoryExists(dir_path.c_str())) {
61 return true;
62 }
63
64 static constexpr int kMaxDescriptors = 4; // Limit the need for nftw() to re-open descriptors.
65 if (nftw(dir_path.c_str(), NftwCleanUpCallback, kMaxDescriptors, FTW_DEPTH | FTW_MOUNT) != 0) {
66 LOG(ERROR) << "Failed to clean-up '" << dir_path << "'";
67 return false;
68 }
69
70 if (rmdir(dir_path.c_str()) != 0) {
71 // It's possible that we are not able to remove the directory itself. For example, when
72 // odrefresh is running in CompOS, the staging dir is prepared beforehand passed to the VM as an
73 // FD. In this case, just log and ignore the error. It's okay to keep the directory.
74 LOG(WARNING) << "Failed to delete '" << dir_path << "'";
75 }
76
77 return true;
78 }
79
EnsureDirectoryExists(const std::string & absolute_path)80 WARN_UNUSED bool EnsureDirectoryExists(const std::string& absolute_path) {
81 if (absolute_path.empty() || absolute_path[0] != '/') {
82 LOG(ERROR) << "Path not absolute '" << absolute_path << "'";
83 return false;
84 }
85 std::string path;
86 for (const std::string& directory : android::base::Split(absolute_path, "/")) {
87 path.append("/").append(directory);
88 if (!OS::DirectoryExists(path.c_str())) {
89 static constexpr mode_t kDirectoryMode = S_IRWXU | S_IRGRP | S_IXGRP| S_IROTH | S_IXOTH;
90 if (mkdir(path.c_str(), kDirectoryMode) != 0) {
91 PLOG(ERROR) << "Could not create directory: " << path;
92 return false;
93 }
94 }
95 }
96 return true;
97 }
98
GetFreeSpace(const std::string & path,uint64_t * bytes)99 bool GetFreeSpace(const std::string& path, uint64_t* bytes) {
100 struct statvfs sv;
101 if (statvfs(path.c_str(), &sv) != 0) {
102 PLOG(ERROR) << "statvfs '" << path << "'";
103 return false;
104 }
105 *bytes = sv.f_bfree * sv.f_bsize;
106 return true;
107 }
108
GetUsedSpace(const std::string & path,uint64_t * bytes)109 bool GetUsedSpace(const std::string& path, uint64_t* bytes) {
110 static constexpr std::string_view kCurrentDirectory{"."};
111 static constexpr std::string_view kParentDirectory{".."};
112 static constexpr size_t kBytesPerBlock = 512; // see manual page for stat(2).
113
114 uint64_t file_bytes = 0;
115 std::queue<std::string> unvisited;
116 unvisited.push(path);
117 while (!unvisited.empty()) {
118 std::string current = unvisited.front();
119 unvisited.pop();
120 std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(current.c_str()), closedir);
121 if (!dir) {
122 continue;
123 }
124 for (auto entity = readdir(dir.get()); entity != nullptr; entity = readdir(dir.get())) {
125 std::string_view name{entity->d_name};
126 if (name == kCurrentDirectory || name == kParentDirectory) {
127 continue;
128 }
129 std::string entity_name = current + "/" + entity->d_name;
130 if (entity->d_type == DT_DIR) {
131 unvisited.push(entity_name.c_str());
132 } else if (entity->d_type == DT_REG) {
133 struct stat sb;
134 if (stat(entity_name.c_str(), &sb) != 0) {
135 PLOG(ERROR) << "Failed to stat() file " << entity_name;
136 continue;
137 }
138 file_bytes += sb.st_blocks * kBytesPerBlock;
139 }
140 }
141 }
142 *bytes = file_bytes;
143 return true;
144 }
145
146 } // namespace odrefresh
147 } // namespace art
148