The OTA library enables you to manage the notification of a newly available update, download the update, and perform cryptographic verification of the firmware update. Using the library, you can logically separate firmware updates from the application running on your devices. The OTA library can share a network connection with the application, saving memory in resource-constrained devices. In addition, the OTA library lets you define application-specific logic for testing, committing, or rolling back a firmware update. The library supports different application protocols like Message Queuing Telemetry Transport (MQTT) and Hypertext Transfer Protocol (HTTP), and provides various configuration options you can fine tune depending on network type and conditions. This library is distributed under the MIT Open Source License.
This library has gone through code quality checks including verification that no function has a GNU Complexity score over 8. This library has also undergone static code analysis from Coverity static analysis.
See memory requirements for this library here.
AWS IoT Over-the-air Update Library v3.4.0 source code is part of the FreeRTOS 202210.00 LTS release.
AWS IoT Over-the-air Update Library v3.3.0 source code is part of the FreeRTOS 202012.01 LTS release.
The AWS IoT Over-the-air Updates library exposes configuration macros that are required for building the library. A list of all the configurations and their default values are defined in ota_config_defaults.h. To provide custom values for the configuration macros, a custom config file named ota_config.h can be provided by the user application to the library.
By default, a ota_config.h custom config is required to build the library. To disable this requirement and build the library with default configuration values, provide OTA_DO_NOT_USE_CUSTOM_CONFIG as a compile time preprocessor macro.
The otaFilePaths.cmake file contains the information of all source files and the header include paths required to build the AWS IoT Over-the-air Updates library.
As mentioned in the previous section, either a custom config file (i.e. ota_config.h) OR the OTA_DO_NOT_USE_CUSTOM_CONFIG macro needs to be provided to build the AWS IoT Over-the-air Updates library.
For a CMake example of building the AWS IoT Over-the-air Updates library with the otaFilePaths.cmake file, refer to the coverity_analysis library target in the test/CMakeLists.txt file.
By default, the submodules in this repository are configured with update=none in .gitmodules to avoid increasing clone time and disk space usage of other repositories (like AWS IoT Device SDK for Embedded C that submodules this repository).
To build unit tests, the submodule dependency of CMock is required. Use the following command to clone the submodule:
git submodule update --checkout --init --recursive test/unit-test/CMock
- For building the library, CMake 3.13.0 or later and a C90 compiler.
- For running unit tests, Ruby 2.0.0 or later is additionally required for the CMock test framework (that we use).
- For running the coverage target, gcov and lcov are additionally required.
-
Go to the root directory of this repository. (Make sure that the CMock submodule is cloned as described above.)
-
Run the cmake command:
cmake -S test -B build -
Run this command to build the library and unit tests:
make -C build all -
The generated test executables will be present in
build/bin/testsfolder. -
Run
cd build && ctestto execute all tests and view the test run summary.
The following table lists equivalent API function signatures in v2.0.0 (Release Candidate) and v3.4.0 declared in ota.h
| v2.0.0 (Release Candidate) | v3.4.0 | Notes |
|---|---|---|
OtaState_t OTA_Shutdown( uint32_t ticksToWait ); |
OtaState_t OTA_Shutdown( uint32_t ticksToWait, uint8_t unsubscribeFlag ); |
unsubscribeFlag indicates if unsubscribe operations should be performed from the job topics when shutdown is called. Set this as 1 to unsubscribe, 0 otherwise. |
Refer to OTA Migration document for the summary of updates to the API. Migration document for OTA PAL also provides a summary of updates required for upgrading the OTA-PAL to work with v3.4.0 of the library.
In order to support AWS IoT Over-the-air Updates on your device, it is necessary to provide the following components:
For enabling data transfer over HTTP dataplane the following component should also be provided:
NOTE When using OTA over HTTP dataplane, MQTT is required for control plane operations and should also be provided.
To learn more about CBMC and proofs specifically, review the training material here.
The test/cbmc/proofs directory contains CBMC proofs.
In order to run these proofs you will need to install CBMC and other tools by following the instructions here.
To run a single CBMC proof locally, you can build the Makefile in any of the CBMC proofs. The Makefile is located in the test/cbmc/proof/<the proof you want>/ directory.
Running make will produce a HTML-based report nearly identical to the one produced by the CI step.
A couple notes about CBMC Proofs
- macOS doesn't implement POSIX message queues (
mqueue.h); - It is possible that macOS fails to recognize your loop unwinding identifiers for function from the C standard libraries. For this case, you'll want to use the
__builtin___<function>_chkidentifier, e.g., instead of usingmemcpyadd__builtin___memcpy_chk.- For example, the requestJob_Mqtt proof fails on macOS with the following error:
Loop unwinding failures
[trace] __builtin___strncpy_chk.unwind.0 in line 36 in file <builtin-library-__builtin___strncpy_chk>
To solve this issue, replace strncpy with __builtin___strncpy_ch on this line.
Please refer to the demos of the AWS IoT Over-the-air Updates library in the following location for reference examples on POSIX and FreeRTOS:
| Platform | Location |
|---|---|
| POSIX | AWS IoT Device SDK for Embedded C |
| FreeRTOS | FreeRTOS/FreeRTOS |
| FreeRTOS | FreeRTOS AWS Reference Integrations |
For pre-generated documentation, please see the documentation linked in the locations below:
| Location |
|---|
| AWS IoT Device SDK for Embedded C |
| FreeRTOS.org |
Note that the latest included version of coreMQTT may differ across repositories.
The Doxygen references were created using Doxygen version 1.9.2. To generate the Doxygen pages, please run the following command from the root of this repository:
doxygen docs/doxygen/config.doxyfileSee CONTRIBUTING.md for information on contributing.