1 /*
2 * Copyright (C) 2018 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 "idmap2/FileUtils.h"
18
19 #include <dirent.h>
20 #include <sys/types.h>
21 #include <unistd.h>
22
23 #include <cerrno>
24 #include <climits>
25 #include <cstdlib>
26 #include <cstring>
27 #include <fstream>
28 #include <memory>
29 #include <string>
30 #include <utility>
31 #include <vector>
32
33 #include "android-base/file.h"
34 #include "android-base/macros.h"
35 #include "android-base/stringprintf.h"
36 #include "private/android_filesystem_config.h"
37
38 namespace android::idmap2::utils {
39
FindFiles(const std::string & root,bool recurse,const FindFilesPredicate & predicate)40 std::unique_ptr<std::vector<std::string>> FindFiles(const std::string& root, bool recurse,
41 const FindFilesPredicate& predicate) {
42 DIR* dir = opendir(root.c_str());
43 if (dir == nullptr) {
44 return nullptr;
45 }
46 std::unique_ptr<std::vector<std::string>> vector(new std::vector<std::string>());
47 struct dirent* dirent;
48 while ((dirent = readdir(dir)) != nullptr) {
49 const std::string path = root + "/" + dirent->d_name;
50 if (predicate(dirent->d_type, path)) {
51 vector->push_back(path);
52 }
53 if (recurse && dirent->d_type == DT_DIR && strcmp(dirent->d_name, ".") != 0 &&
54 strcmp(dirent->d_name, "..") != 0) {
55 auto sub_vector = FindFiles(path, recurse, predicate);
56 if (!sub_vector) {
57 closedir(dir);
58 return nullptr;
59 }
60 vector->insert(vector->end(), sub_vector->begin(), sub_vector->end());
61 }
62 }
63 closedir(dir);
64
65 return vector;
66 }
67
ReadFile(const std::string & path)68 std::unique_ptr<std::string> ReadFile(const std::string& path) {
69 std::unique_ptr<std::string> str(new std::string());
70 std::ifstream fin(path);
71 str->append({std::istreambuf_iterator<char>(fin), std::istreambuf_iterator<char>()});
72 fin.close();
73 return str;
74 }
75
ReadFile(int fd)76 std::unique_ptr<std::string> ReadFile(int fd) {
77 static constexpr const size_t kBufSize = 1024;
78
79 std::unique_ptr<std::string> str(new std::string());
80 char buf[kBufSize];
81 ssize_t r;
82 while ((r = read(fd, buf, sizeof(buf))) > 0) {
83 str->append(buf, r);
84 }
85 return r == 0 ? std::move(str) : nullptr;
86 }
87
88 #ifdef __ANDROID__
UidHasWriteAccessToPath(uid_t uid,const std::string & path)89 bool UidHasWriteAccessToPath(uid_t uid, const std::string& path) {
90 // resolve symlinks and relative paths; the directories must exist
91 std::string canonical_path;
92 if (!base::Realpath(base::Dirname(path), &canonical_path)) {
93 return false;
94 }
95
96 const std::string cache_subdir = base::StringPrintf("%s/", kIdmapCacheDir);
97 if (canonical_path == kIdmapCacheDir ||
98 canonical_path.compare(0, cache_subdir.size(), cache_subdir) == 0) {
99 // limit access to /data/resource-cache to root and system
100 return uid == AID_ROOT || uid == AID_SYSTEM;
101 }
102 return true;
103 }
104 #else
UidHasWriteAccessToPath(uid_t uid ATTRIBUTE_UNUSED,const std::string & path ATTRIBUTE_UNUSED)105 bool UidHasWriteAccessToPath(uid_t uid ATTRIBUTE_UNUSED, const std::string& path ATTRIBUTE_UNUSED) {
106 return true;
107 }
108 #endif
109
110 } // namespace android::idmap2::utils
111