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1 /*
2  * Copyright (C) 2016 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 CHRE_PLATFORM_SLPI_PLATFORM_NANOAPP_BASE_H_
18 #define CHRE_PLATFORM_SLPI_PLATFORM_NANOAPP_BASE_H_
19 
20 #include <cstddef>
21 #include <cstdint>
22 
23 #include "chre/platform/shared/nanoapp_support_lib_dso.h"
24 #include "chre/util/entry_points.h"
25 
26 namespace chre {
27 
28 /**
29  * SLPI-specific nanoapp functionality.
30  */
31 class PlatformNanoappBase {
32  public:
33   /**
34    * Sets app info that will be used later when the app is loaded into the
35    * system.
36    *
37    * @param appId The unique app identifier associated with this binary
38    * @param appVersion An application-defined version number
39    * @param appFilename The filename of the app that should be loaded from disk
40    * @param targetApiVersion The target API version the nanoapp was compiled for
41    *
42    * @return true if the info was successfully stored
43    */
44   bool setAppInfo(uint64_t appId, uint32_t appVersion, const char *appFilename,
45                   uint32_t targetApiVersion);
46 
47   /**
48    * Reserves buffer space for a nanoapp's binary. This method should be called
49    * before copyNanoappFragment is called.
50    *
51    * @param appId The unique app identifier associated with this binary
52    * @param appVersion An application-defined version number
53    * @param appFlags The flags provided by the app being loaded
54    * @param appBinaryLen Size of appBinary, in bytes
55    *
56    * @return true if the allocation was successful, false otherwise
57    */
58   bool reserveBuffer(uint64_t appId, uint32_t appVersion, uint32_t appFlags,
59                      size_t appBinarylen, uint32_t targetApiVersion);
60 
61   /**
62    * Copies the (possibly fragmented) application binary data into the allocated
63    * buffer, and updates the pointer to the next address to write into. The
64    * application may be invalid - full checking and initialization happens just
65    * before invoking start() nanoapp entry point.
66    *
67    * @param buffer The pointer to the buffer
68    * @param bufferSize The size of the buffer in bytes
69    *
70    * @return true if the reserved buffer did not overflow, false otherwise
71    */
72   bool copyNanoappFragment(const void *buffer, size_t bufferSize);
73 
74   /**
75    * Associate this Nanoapp instance with a nanoapp that is statically built
76    * into the CHRE binary with the given app info structure.
77    */
78   void loadStatic(const struct chreNslNanoappInfo *appInfo);
79 
80   /**
81    * @return true if the app's binary data is resident in memory or if the app's
82    *         filename is saved, i.e. all binary fragments are loaded through
83    *         copyNanoappFragment, loadFromFile/loadStatic() was successful, or
84    *         setAppInfo was successful.
85    */
86   bool isLoaded() const;
87 
88   /**
89    * @return true if the app runs in micro-image.
90    */
91   bool isUimgApp() const;
92 
93   /**
94    * Retrieves the nanoapp's version string. This is intended to be a human
95    * readable version string to aid in debugging (ie: commit hash). This must
96    * always return a valid string so if none is available it is recommended to
97    * return "<undefined>" or similar.
98    */
99   const char *getAppVersionString() const;
100 
101  protected:
102   //! The app ID we received in the metadata alongside the nanoapp binary. This
103   //! is also included in (and checked against) mAppInfo.
104   uint64_t mExpectedAppId;
105 
106   //! The application-defined version number we received in the metadata
107   //! alongside the nanoapp binary. This is also included in (and checked
108   //! against) mAppInfo.
109   uint32_t mExpectedAppVersion = 0;
110 
111   //! The app target API version in the metadata alongside the nanoapp binary.
112   uint32_t mExpectedTargetApiVersion = 0;
113 
114   //! Buffer containing the complete DSO binary - only populated if
115   //! copyNanoappFragment() was used to load this nanoapp
116   void *mAppBinary = nullptr;
117   size_t mAppBinaryLen = 0;
118 
119   //! Null-terminated ASCII string containing the file name that contains the
120   //! app binary to be loaded. This is used over mAppBinary to load the nanoapp
121   //! if set.
122   char *mAppFilename = nullptr;
123 
124   //! The dynamic shared object (DSO) handle returned by dlopenbuf()
125   void *mDsoHandle = nullptr;
126 
127   //! Pointer to the app info structure within this nanoapp
128   const struct chreNslNanoappInfo *mAppInfo = nullptr;
129 
130   //! Set to true if this app is built into the CHRE binary, and was loaded via
131   //! loadStatic(). In this case, the member variables above are not valid or
132   //! applicable.
133   bool mIsStatic = false;
134 
135   //! True if the nanoapp runs in micro-image.
136   bool mIsUimgApp = false;
137 
138   //! The number of bytes of the binary that has been loaded so far.
139   size_t mBytesLoaded = 0;
140 
141   /**
142    * Calls through to openNanoappFromBuffer or openNanoappFromFile, depending on
143    * how this nanoapp was loaded.
144    */
145   bool openNanoapp();
146 
147   /**
148    * Calls dlopenbuf on the app binary, and fetches and validates the app info
149    * pointer. This will result in execution of any on-load handlers (e.g. static
150    * global constructors) in the nanoapp.
151    *
152    * @return true if the app was opened successfully and the app info structure
153    *         passed validation
154    */
155   bool openNanoappFromBuffer();
156 
157   /**
158    * Calls dlopen on the app file name, and fetches and validates the app info
159    * pointer. This will result in execution of any on-load handlers (e.g. static
160    * global constructors) in the nanoapp.
161    *
162    * @return true if the app was opened successfully and the app info structure
163    *         passed validation
164    */
165   bool openNanoappFromFile();
166 
167   /**
168    * Loads the nanoapp symbols from the currently loaded binary and verifies
169    * they match the expected information the nanoapp should have.
170    *
171    * @return true if the app info structure passed validation.
172    */
173   bool verifyNanoappInfo();
174 
175   /**
176    * Releases the DSO handle if it was active, by calling dlclose(). This will
177    * result in execution of any unload handlers in the nanoapp.
178    */
179   void closeNanoapp();
180 };
181 
182 }  // namespace chre
183 
184 #endif  // CHRE_PLATFORM_SLPI_PLATFORM_NANOAPP_BASE_H_
185