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 #include "uevent_handler.h"
33 
34 namespace android {
35 namespace init {
36 
37 class Permissions {
38   public:
39     friend void TestPermissions(const Permissions& expected, const Permissions& test);
40 
41     Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid);
42 
43     bool Match(const std::string& path) const;
44 
perm()45     mode_t perm() const { return perm_; }
uid()46     uid_t uid() const { return uid_; }
gid()47     gid_t gid() const { return gid_; }
48 
49   protected:
name()50     const std::string& name() const { return name_; }
51 
52   private:
53     std::string name_;
54     mode_t perm_;
55     uid_t uid_;
56     gid_t gid_;
57     bool prefix_;
58     bool wildcard_;
59 };
60 
61 class SysfsPermissions : public Permissions {
62   public:
63     friend void TestSysfsPermissions(const SysfsPermissions& expected, const SysfsPermissions& test);
64 
SysfsPermissions(const std::string & name,const std::string & attribute,mode_t perm,uid_t uid,gid_t gid)65     SysfsPermissions(const std::string& name, const std::string& attribute, mode_t perm, uid_t uid,
66                      gid_t gid)
67         : Permissions(name, perm, uid, gid), attribute_(attribute) {}
68 
69     bool MatchWithSubsystem(const std::string& path, const std::string& subsystem) const;
70     void SetPermissions(const std::string& path) const;
71 
72   private:
73     const std::string attribute_;
74 };
75 
76 class Subsystem {
77   public:
78     friend class SubsystemParser;
79     friend void TestSubsystems(const Subsystem& expected, const Subsystem& test);
80 
81     enum DevnameSource {
82         DEVNAME_UEVENT_DEVNAME,
83         DEVNAME_UEVENT_DEVPATH,
84     };
85 
Subsystem()86     Subsystem() {}
Subsystem(std::string name)87     Subsystem(std::string name) : name_(std::move(name)) {}
Subsystem(std::string name,DevnameSource source,std::string dir_name)88     Subsystem(std::string name, DevnameSource source, std::string dir_name)
89         : name_(std::move(name)), devname_source_(source), dir_name_(std::move(dir_name)) {}
90 
91     // Returns the full path for a uevent of a device that is a member of this subsystem,
92     // according to the rules parsed from ueventd.rc
ParseDevPath(const Uevent & uevent)93     std::string ParseDevPath(const Uevent& uevent) const {
94         std::string devname = devname_source_ == DEVNAME_UEVENT_DEVNAME
95                                       ? uevent.device_name
96                                       : android::base::Basename(uevent.path);
97 
98         return dir_name_ + "/" + devname;
99     }
100 
101     bool operator==(const std::string& string_name) const { return name_ == string_name; }
102 
103   private:
104     std::string name_;
105     DevnameSource devname_source_ = DEVNAME_UEVENT_DEVNAME;
106     std::string dir_name_ = "/dev";
107 };
108 
109 class DeviceHandler : public UeventHandler {
110   public:
111     friend class DeviceHandlerTester;
112 
113     DeviceHandler();
114     DeviceHandler(std::vector<Permissions> dev_permissions,
115                   std::vector<SysfsPermissions> sysfs_permissions, std::vector<Subsystem> subsystems,
116                   std::set<std::string> boot_devices, bool skip_restorecon);
117     virtual ~DeviceHandler() = default;
118 
119     void HandleUevent(const Uevent& uevent) override;
120     void ColdbootDone() override;
121 
122     std::vector<std::string> GetBlockDeviceSymlinks(const Uevent& uevent) const;
123 
124   private:
125     bool FindPlatformDevice(std::string path, std::string* platform_device_path) const;
126     std::tuple<mode_t, uid_t, gid_t> GetDevicePermissions(
127         const std::string& path, const std::vector<std::string>& links) const;
128     void MakeDevice(const std::string& path, bool block, int major, int minor,
129                     const std::vector<std::string>& links) const;
130     void HandleDevice(const std::string& action, const std::string& devpath, bool block, int major,
131                       int minor, const std::vector<std::string>& links) const;
132     void FixupSysPermissions(const std::string& upath, const std::string& subsystem) const;
133     void HandleAshmemUevent(const Uevent& uevent);
134 
135     std::vector<Permissions> dev_permissions_;
136     std::vector<SysfsPermissions> sysfs_permissions_;
137     std::vector<Subsystem> subsystems_;
138     std::set<std::string> boot_devices_;
139     bool skip_restorecon_;
140     std::string sysfs_mount_point_;
141 };
142 
143 // Exposed for testing
144 void SanitizePartitionName(std::string* string);
145 
146 }  // namespace init
147 }  // namespace android
148 
149 #endif
150