1 /*
2 * Copyright (C) 2013 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 <dirent.h>
18
19 #include <fcntl.h>
20 #include <errno.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #include "private/bionic_macros.h"
26 #include "private/ScopedReaddir.h"
27
28 // A smart pointer to the scandir dirent**.
29 class ScandirResult {
30 public:
ScandirResult()31 ScandirResult() : names_(nullptr), size_(0), capacity_(0) {
32 }
33
~ScandirResult()34 ~ScandirResult() {
35 while (size_ > 0) {
36 free(names_[--size_]);
37 }
38 free(names_);
39 }
40
size()41 size_t size() {
42 return size_;
43 }
44
release()45 dirent** release() {
46 dirent** result = names_;
47 names_ = nullptr;
48 size_ = capacity_ = 0;
49 return result;
50 }
51
Add(dirent * entry)52 bool Add(dirent* entry) {
53 if (size_ >= capacity_) {
54 size_t new_capacity = capacity_ + 32;
55 dirent** new_names =
56 reinterpret_cast<dirent**>(realloc(names_, new_capacity * sizeof(dirent*)));
57 if (new_names == nullptr) {
58 return false;
59 }
60 names_ = new_names;
61 capacity_ = new_capacity;
62 }
63
64 dirent* copy = CopyDirent(entry);
65 if (copy == nullptr) {
66 return false;
67 }
68 names_[size_++] = copy;
69 return true;
70 }
71
Sort(int (* comparator)(const dirent **,const dirent **))72 void Sort(int (*comparator)(const dirent**, const dirent**)) {
73 // If we have entries and a comparator, sort them.
74 if (size_ > 0 && comparator != nullptr) {
75 qsort(names_, size_, sizeof(dirent*),
76 reinterpret_cast<int (*)(const void*, const void*)>(comparator));
77 }
78 }
79
80 private:
81 dirent** names_;
82 size_t size_;
83 size_t capacity_;
84
CopyDirent(dirent * original)85 static dirent* CopyDirent(dirent* original) {
86 // Allocate the minimum number of bytes necessary, rounded up to a 4-byte boundary.
87 size_t size = ((original->d_reclen + 3) & ~3);
88 dirent* copy = reinterpret_cast<dirent*>(malloc(size));
89 memcpy(copy, original, original->d_reclen);
90 return copy;
91 }
92
93 BIONIC_DISALLOW_COPY_AND_ASSIGN(ScandirResult);
94 };
95
scandirat(int parent_fd,const char * dir_name,dirent *** name_list,int (* filter)(const dirent *),int (* comparator)(const dirent **,const dirent **))96 int scandirat(int parent_fd, const char* dir_name, dirent*** name_list,
97 int (*filter)(const dirent*),
98 int (*comparator)(const dirent**, const dirent**)) {
99 DIR* dir = nullptr;
100 if (parent_fd == AT_FDCWD) {
101 dir = opendir(dir_name);
102 } else {
103 int dir_fd = openat(parent_fd, dir_name, O_CLOEXEC | O_DIRECTORY | O_RDONLY);
104 if (dir_fd != -1) {
105 dir = fdopendir(dir_fd);
106 }
107 }
108
109 ScopedReaddir reader(dir);
110 if (reader.IsBad()) {
111 return -1;
112 }
113
114 ScandirResult names;
115 dirent* entry;
116 while ((entry = reader.ReadEntry()) != nullptr) {
117 // If we have a filter, skip names that don't match.
118 if (filter != nullptr && !(*filter)(entry)) {
119 continue;
120 }
121 names.Add(entry);
122 }
123
124 names.Sort(comparator);
125
126 size_t size = names.size();
127 *name_list = names.release();
128 return size;
129 }
130 __strong_alias(scandirat64, scandirat);
131
scandir(const char * dir_path,dirent *** name_list,int (* filter)(const dirent *),int (* comparator)(const dirent **,const dirent **))132 int scandir(const char* dir_path, dirent*** name_list,
133 int (*filter)(const dirent*),
134 int (*comparator)(const dirent**, const dirent**)) {
135 return scandirat(AT_FDCWD, dir_path, name_list, filter, comparator);
136 }
137 __strong_alias(scandir64, scandir);
138