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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 "chre/util/entry_points.h"
32 
33 #include <stdint.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(2)
45 
46 //! The symbol name expected from the nanoapp's definition of its info struct
47 #define CHRE_NSL_DSO_NANOAPP_INFO_SYMBOL_NAME  "_chreNslDsoNanoappInfo"
48 
49 //! Maximum length of vendor and name strings
50 #define CHRE_NSL_DSO_NANOAPP_STRING_MAX_LEN  (32)
51 
52 /**
53  * DSO-based nanoapps must expose this struct under a symbol whose name is given
54  * by CHRE_NSL_DSO_NANOAPP_INFO_SYMBOL_NAME. When the nanoapp is loaded, dlsym()
55  * will be used to locate this symbol to register the nanoapp with the system.
56  */
57 struct chreNslNanoappInfo {
58   //! @see CHRE_NSL_NANOAPP_INFO_MAGIC
59   uint32_t magic;
60 
61   //! @see CHRE_NSL_NANOAPP_INFO_STRUCT_MINOR_VERSION
62   uint8_t structMinorVersion;
63 
64   //! Set to 1 if this nanoapp is a "system nanoapp" that should not show up in
65   //! the context hub HAL, likely because it implements some device
66   //! functionality beneath the HAL.
67   uint8_t isSystemNanoapp:1;
68 
69   //! Set to 1 if this nanoapp runs in tightly coupled memory. This flag is only
70   //! relevant to platforms that have the ability to run nanoapps within tightly
71   //! coupled memory.
72   //!
73   //! @since minor version 1
74   uint8_t isTcmNanoapp:1;
75 
76   //! Reserved for future use, set to 0. Assignment of this field to some use
77   //! must be accompanied by an increase of the struct minor version.
78   uint8_t reservedFlags:6;
79   uint8_t reserved;
80 
81   //! The CHRE API version that the nanoapp was compiled against
82   uint32_t targetApiVersion;
83 
84   //! A human-friendly name of the nanoapp vendor (null-terminated string,
85   //! maximum length CHRE_NSL_DSO_NANOAPP_STRING_MAX_LEN)
86   const char *vendor;
87 
88   //! A human-friendly name for the nanoapp (null-terminated string, maximum
89   //! length CHRE_NSL_DSO_NANOAPP_STRING_MAX_LEN)
90   const char *name;
91 
92   //! Identifies the vendor (most significant 5 bytes) and application
93   uint64_t appId;
94 
95   //! Application-specific version number
96   uint32_t appVersion;
97 
98   struct {
99     chreNanoappStartFunction *start;
100     chreNanoappHandleEventFunction *handleEvent;
101     chreNanoappEndFunction *end;
102   } entryPoints;
103 
104   //! Application-specific verison string. This might contain a commit hash at
105   //! which the app was built, but is up to the app itself.
106   //!
107   //! @since minor version 2
108   const char *appVersionString;
109 };
110 
111 /**
112  * Defined as a placeholder to enable future functionality extension.
113  *
114  * @param apiId
115  * @param apiHandle If this function returns true, this will be set to a pointer
116  *        to the associated structure containing the API
117  *
118  * @return true if the requested API is supported, false otherwise
119  */
120 bool chreNslDsoGetApi(uint32_t apiId, void **apiHandle);
121 
122 #ifdef __cplusplus
123 }
124 #endif
125 
126 #endif  // CHRE_PLATFORM_SHARED_NANOAPP_SUPPORT_LIB_DSO_H_
127