Including the BlobContainer system program in a KasperskyOS-based solution
If a solution uses dynamic libraries, the system program BlobContainer must be included in this solution (this system program is provided by the executable file sysroot-aarch64-kos/bin/BlobContainer from KasperskyOS Community Edition).
The BlobContainer program can be included in a solution either automatically or manually. This program is automatically included in a solution by running the CMake commands build_kos_qemu_image() and build_kos_hw_image() if at least one executable file in the solution is linked to a dynamic library. (To disable automatic inclusion of the BlobContainer program in a solution, you need to add the NO_AUTO_BLOB_CONTAINER value to the parameters of the CMake commands build_kos_qemu_image() and build_kos_hw_image().) If programs in a solution work with dynamic libraries using only a POSIX interface (the dlopen(), dlsym(), dlerror(), and dlclose() functions), the BlobContainer program needs to be manually included in the solution.
The VFS working with files of dynamic libraries must be a separate process. You need to create an IPC channel from the process of the BlobContainer program to the VFS process.
You must create IPC channels from the processes using dynamic libraries to the process of the BlobContainer program. These IPC channels can be created statically or dynamically. If a statically created IPC channel is not available, the client and server parts of the BlobContainer program attempt to dynamically create an IPC channel using the name server.
If the BlobContainer program is automatically included in a solution, the @INIT_EXTERNAL_ENTITIES@, @INIT_<program name>_ENTITY_CONNECTIONS@ and @INIT_<program name>_ENTITY_CONNECTIONS+@ macros used in the init.yaml.in file automatically create within the init description dictionaries of IPC channels that enable static creation of IPC channels from processes created based on executable files linked to dynamic libraries to the process of the BlobContainer program. (The process of the BlobContainer program receives the name kl.bc.BlobContainer, while the IPC channels receive the name kl.BlobContainer.) However, dictionaries of IPC channels to the BlobContainer program process are not automatically created for processes that work with dynamic libraries using only a POSIX interface. To ensure that the required IPC channels are statically created, these dictionaries must be manually created (these IPC channels must have the name kl.BlobContainer).
If the BlobContainer program is manually included in the solution and you need to statically create IPC channels from processes using dynamic libraries to the BlobContainer program process, you must manually create dictionaries of the required IPC channels in the init description. By default, the IPC channel to the BlobContainer program process has the name kl.BlobContainer. However, this name can be changed through the environment variable _BLOB_CONTAINER_BACKEND. This variable must be defined for the BlobContainer process and for processes using dynamic libraries.
The environment variable _BLOB_CONTAINER_BACKEND defines not only the name of statically created IPC channels to the BlobContainer program process, but also defines the endpoint name that is published on the name server and used to dynamically create IPC channels to the BlobContainer program process. This is convenient when multiple processes of the BlobContainer program are running simultaneously (for example, to isolate its own dynamic libraries from external ones), and when different processes using dynamic libraries must interact over IPC with different processes of the BlobContainer program. In this case, you need to define different values for the environment variable _BLOB_CONTAINER_BACKEND for different processes of the BlobContainer program, and then use these values for the environment variable _BLOB_CONTAINER_BACKEND for processes using dynamic libraries. The specific value must be selected depending on the specific process of the BlobContainer program that requires the dynamically created IPC channel.
Example use of the environment variable _BLOB_CONTAINER_BACKEND in the init.yaml.in file:
Example use of the environment variable _BLOB_CONTAINER_BACKEND in CMake commands: