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      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 "private/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   DISALLOW_COPY_AND_ASSIGN(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   const char* required_prefix_;
     69 };
     70 
     71 class PasswdFile {
     72  public:
     73   PasswdFile(const char* filename, const char* required_prefix);
     74 
     75   bool FindById(uid_t id, passwd_state_t* passwd_state);
     76   bool FindByName(const char* name, passwd_state_t* passwd_state);
     77   void Unmap() {
     78     mmap_file_.Unmap();
     79   }
     80 
     81   DISALLOW_COPY_AND_ASSIGN(PasswdFile);
     82 
     83  private:
     84   MmapFile mmap_file_;
     85 };
     86 
     87 class GroupFile {
     88  public:
     89   GroupFile(const char* filename, const char* required_prefix);
     90 
     91   bool FindById(gid_t id, group_state_t* group_state);
     92   bool FindByName(const char* name, group_state_t* group_state);
     93   void Unmap() {
     94     mmap_file_.Unmap();
     95   }
     96 
     97   DISALLOW_COPY_AND_ASSIGN(GroupFile);
     98 
     99  private:
    100   MmapFile mmap_file_;
    101 };
    102