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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_SHARED_NANOAPP_SUPPORT_LIB_DSO_H_
18 #define CHRE_PLATFORM_SHARED_NANOAPP_SUPPORT_LIB_DSO_H_
19 
20 /**
21  * @file
22  * This provides the interface that the dynamic shared object (DSO) nanoapp
23  * nanoapp support library (NSL) uses to interface with the underlying CHRE
24  * implementation in a compatible manner.
25  *
26  * This header file must retain compatibility with C, and have minimal or no
27  * dependencies on other CHRE system header files, as it will be used when
28  * compiling external/dynamic nanoapps.
29  */
30 
31 #include <stdint.h>
32 
33 #include "chre_api/chre.h"
34 
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
38 
39 //! Special magic value to uniquely identify the nanoapp info structure
40 #define CHRE_NSL_NANOAPP_INFO_MAGIC UINT32_C(0x50e69977)
41 
42 //! The minor version in the nanoapp info structure to determine which fields
43 //! are available to support backwards compatibility.
44 #define CHRE_NSL_NANOAPP_INFO_STRUCT_MINOR_VERSION UINT8_C(3)
45 
46 //! Explicit definition of nanoapp info structure minor version three (3),
47 //! can be used to determine if a nanoapp supports app permissions declaration
48 #define CHRE_NSL_NANOAPP_INFO_STRUCT_MINOR_VERSION_3 UINT8_C(3)
49 
50 //! The symbol name expected from the nanoapp's definition of its info struct
51 #define CHRE_NSL_DSO_NANOAPP_INFO_SYMBOL_NAME "_chreNslDsoNanoappInfo"
52 
53 //! The symbol name expected from the nanoapp's definition of its unstable ID
54 //! char array
55 #define CHRE_NSL_DSO_NANOAPP_UNSTABLE_ID_SYMBOL_NAME "_chreNanoappUnstableId"
56 
57 //! Maximum length of vendor and name strings
58 #define CHRE_NSL_DSO_NANOAPP_STRING_MAX_LEN (32)
59 
60 //! @see nanoappStart()
61 typedef bool(chreNanoappStartFunction)(void);
62 
63 //! @see nanoappHandleEvent()
64 typedef void(chreNanoappHandleEventFunction)(uint32_t senderInstanceId,
65                                              uint16_t eventType,
66                                              const void *eventData);
67 
68 //! @see nanoappEnd()
69 typedef void(chreNanoappEndFunction)(void);
70 
71 /**
72  * DSO-based nanoapps must expose this struct under a symbol whose name is given
73  * by CHRE_NSL_DSO_NANOAPP_INFO_SYMBOL_NAME. When the nanoapp is loaded, dlsym()
74  * will be used to locate this symbol to register the nanoapp with the system.
75  */
76 struct chreNslNanoappInfo {
77   //! @see CHRE_NSL_NANOAPP_INFO_MAGIC
78   uint32_t magic;
79 
80   //! @see CHRE_NSL_NANOAPP_INFO_STRUCT_MINOR_VERSION
81   uint8_t structMinorVersion;
82 
83   //! Set to 1 if this nanoapp is a "system nanoapp" that should not show up in
84   //! the context hub HAL, likely because it implements some device
85   //! functionality beneath the HAL.
86   uint8_t isSystemNanoapp : 1;
87 
88   //! Set to 1 if this nanoapp runs in tightly coupled memory. This flag is only
89   //! relevant to platforms that have the ability to run nanoapps within tightly
90   //! coupled memory.
91   //!
92   //! @since minor version 1
93   uint8_t isTcmNanoapp : 1;
94 
95   //! Reserved for future use, set to 0. Assignment of this field to some use
96   //! must be accompanied by an increase of the struct minor version.
97   uint8_t reservedFlags : 6;
98   uint8_t reserved;
99 
100   //! The CHRE API version that the nanoapp was compiled against
101   uint32_t targetApiVersion;
102 
103   //! A human-friendly name of the nanoapp vendor (null-terminated string,
104   //! maximum length CHRE_NSL_DSO_NANOAPP_STRING_MAX_LEN)
105   const char *vendor;
106 
107   //! A human-friendly name for the nanoapp (null-terminated string, maximum
108   //! length CHRE_NSL_DSO_NANOAPP_STRING_MAX_LEN)
109   const char *name;
110 
111   //! Identifies the vendor (most significant 5 bytes) and application
112   uint64_t appId;
113 
114   //! Application-specific version number
115   uint32_t appVersion;
116 
117   struct {
118     chreNanoappStartFunction *start;
119     chreNanoappHandleEventFunction *handleEvent;
120     chreNanoappEndFunction *end;
121   } entryPoints;
122 
123   //! Application-specific verison string. This might contain a commit hash at
124   //! which the app was built, but is up to the app itself.
125   //!
126   //! @since minor version 2
127   const char *appVersionString;
128 
129   //! Set of permissions that determines what APIs the application is allowed to
130   //! use. See chre/util/system/napp_permissions.h for more details on what
131   //! permissions can be declared here and what their values are.
132   //!
133   //! @since minor version 3
134   uint32_t appPermissions;
135 };
136 
137 /**
138  * Get the Chre Nsl Nanoapp Info object
139  *
140  * @return struct chreNslNanoappInfo
141  */
142 const struct chreNslNanoappInfo *getChreNslDsoNanoappInfo();
143 
144 /**
145  * Defined as a placeholder to enable future functionality extension.
146  *
147  * @param apiId
148  * @param apiHandle If this function returns true, this will be set to a pointer
149  *        to the associated structure containing the API
150  *
151  * @return true if the requested API is supported, false otherwise
152  */
153 bool chreNslDsoGetApi(uint32_t apiId, void **apiHandle);
154 
155 #ifdef __cplusplus
156 }
157 #endif
158 
159 #endif  // CHRE_PLATFORM_SHARED_NANOAPP_SUPPORT_LIB_DSO_H_
160