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      1 /*
      2  * Copyright (C) 2007 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 #ifndef _INIT_DEVICES_H
     18 #define _INIT_DEVICES_H
     19 
     20 #include <sys/stat.h>
     21 #include <sys/types.h>
     22 
     23 #include <algorithm>
     24 #include <set>
     25 #include <string>
     26 #include <vector>
     27 
     28 #include <android-base/file.h>
     29 #include <selinux/label.h>
     30 
     31 #include "uevent.h"
     32 
     33 namespace android {
     34 namespace init {
     35 
     36 class Permissions {
     37   public:
     38     Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid);
     39 
     40     bool Match(const std::string& path) const;
     41 
     42     mode_t perm() const { return perm_; }
     43     uid_t uid() const { return uid_; }
     44     gid_t gid() const { return gid_; }
     45 
     46   protected:
     47     const std::string& name() const { return name_; }
     48 
     49   private:
     50     std::string name_;
     51     mode_t perm_;
     52     uid_t uid_;
     53     gid_t gid_;
     54     bool prefix_;
     55     bool wildcard_;
     56 };
     57 
     58 class SysfsPermissions : public Permissions {
     59   public:
     60     SysfsPermissions(const std::string& name, const std::string& attribute, mode_t perm, uid_t uid,
     61                      gid_t gid)
     62         : Permissions(name, perm, uid, gid), attribute_(attribute) {}
     63 
     64     bool MatchWithSubsystem(const std::string& path, const std::string& subsystem) const;
     65     void SetPermissions(const std::string& path) const;
     66 
     67   private:
     68     const std::string attribute_;
     69 };
     70 
     71 class Subsystem {
     72   public:
     73     friend class SubsystemParser;
     74 
     75     Subsystem() {}
     76     Subsystem(std::string name) : name_(std::move(name)) {}
     77 
     78     // Returns the full path for a uevent of a device that is a member of this subsystem,
     79     // according to the rules parsed from ueventd.rc
     80     std::string ParseDevPath(const Uevent& uevent) const {
     81         std::string devname = devname_source_ == DevnameSource::DEVNAME_UEVENT_DEVNAME
     82                                   ? uevent.device_name
     83                                   : android::base::Basename(uevent.path);
     84 
     85         return dir_name_ + "/" + devname;
     86     }
     87 
     88     bool operator==(const std::string& string_name) const { return name_ == string_name; }
     89 
     90   private:
     91     enum class DevnameSource {
     92         DEVNAME_UEVENT_DEVNAME,
     93         DEVNAME_UEVENT_DEVPATH,
     94     };
     95 
     96     std::string name_;
     97     std::string dir_name_ = "/dev";
     98     DevnameSource devname_source_;
     99 };
    100 
    101 class DeviceHandler {
    102   public:
    103     friend class DeviceHandlerTester;
    104 
    105     DeviceHandler();
    106     DeviceHandler(std::vector<Permissions> dev_permissions,
    107                   std::vector<SysfsPermissions> sysfs_permissions, std::vector<Subsystem> subsystems,
    108                   std::set<std::string> boot_devices, bool skip_restorecon);
    109     ~DeviceHandler(){};
    110 
    111     void HandleDeviceEvent(const Uevent& uevent);
    112 
    113     std::vector<std::string> GetBlockDeviceSymlinks(const Uevent& uevent) const;
    114     void set_skip_restorecon(bool value) { skip_restorecon_ = value; }
    115 
    116   private:
    117     bool FindPlatformDevice(std::string path, std::string* platform_device_path) const;
    118     std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(
    119         const std::string& path, const std::vector<std::string>& links) const;
    120     void MakeDevice(const std::string& path, bool block, int major, int minor,
    121                     const std::vector<std::string>& links) const;
    122     void HandleDevice(const std::string& action, const std::string& devpath, bool block, int major,
    123                       int minor, const std::vector<std::string>& links) const;
    124     void FixupSysPermissions(const std::string& upath, const std::string& subsystem) const;
    125 
    126     std::vector<Permissions> dev_permissions_;
    127     std::vector<SysfsPermissions> sysfs_permissions_;
    128     std::vector<Subsystem> subsystems_;
    129     std::set<std::string> boot_devices_;
    130     bool skip_restorecon_;
    131     std::string sysfs_mount_point_;
    132 };
    133 
    134 // Exposed for testing
    135 void SanitizePartitionName(std::string* string);
    136 
    137 }  // namespace init
    138 }  // namespace android
    139 
    140 #endif
    141