1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #pragma once
30 
31 #include <grp.h>
32 #include <pwd.h>
33 
34 #include "private/bionic_lock.h"
35 #include "platform/bionic/macros.h"
36 #include "private/grp_pwd.h"
37 
38 class MmapFile {
39  public:
40   MmapFile(const char* filename, const char* required_prefix);
41 
42   template <typename Line>
43   bool FindById(uid_t uid, Line* line);
44   template <typename Line>
45   bool FindByName(const char* name, Line* line);
46   void Unmap();
47 
48   BIONIC_DISALLOW_IMPLICIT_CONSTRUCTORS(MmapFile);
49 
50  private:
51   enum class FileStatus {
52     Uninitialized,
53     Initialized,
54     Error,
55   };
56 
57   bool GetFile(const char** start, const char** end);
58   bool DoMmap();
59 
60   template <typename Line, typename Predicate>
61   bool Find(Line* line, Predicate predicate);
62 
63   FileStatus status_ = FileStatus::Uninitialized;
64   Lock lock_;
65   const char* filename_ = nullptr;
66   const char* start_ = nullptr;
67   const char* end_ = nullptr;
68 #pragma clang diagnostic push
69 #pragma clang diagnostic ignored "-Wunused-private-field"
70   const char* required_prefix_;
71 #pragma clang diagnostic pop
72 };
73 
74 class PasswdFile {
75  public:
76   PasswdFile(const char* filename, const char* required_prefix);
77 
78   bool FindById(uid_t id, passwd_state_t* passwd_state);
79   bool FindByName(const char* name, passwd_state_t* passwd_state);
Unmap()80   void Unmap() {
81     mmap_file_.Unmap();
82   }
83 
84   BIONIC_DISALLOW_IMPLICIT_CONSTRUCTORS(PasswdFile);
85 
86  private:
87   MmapFile mmap_file_;
88 };
89 
90 class GroupFile {
91  public:
92   GroupFile(const char* filename, const char* required_prefix);
93 
94   bool FindById(gid_t id, group_state_t* group_state);
95   bool FindByName(const char* name, group_state_t* group_state);
Unmap()96   void Unmap() {
97     mmap_file_.Unmap();
98   }
99 
100   BIONIC_DISALLOW_IMPLICIT_CONSTRUCTORS(GroupFile);
101 
102  private:
103   MmapFile mmap_file_;
104 };
105