[#349] Add service name generator to be able to run tests concurrently

[elfenpiff]

Notes for Reviewer

Fixes some parts of the problem but not everything

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5. [x] Branch follows the naming format (iox2-123-introduce-posix-ipc-example)
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   • [x] Commit messages have the issue ID ([#123] Add posix ipc example)
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• [x] Commits are properly organized and messages are according to the guideline
• [x] Unit tests have been written for new behavior
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1. [ ] All open points are addressed and tracked via issues

References

Relates to #349 Closes #475

[elfenpiff]

When set_log_level(LogLevel::TRACE) is active one test fails with this:

ServiceEventTest/0.open_or_create_service_does_exist

      353 [D] Builder { storage_name: FileName { value: FixedSizeByteString<255> { len: 40, data: "26380db3f2d1d21a17def8273faec2e5097cf3e2" } }, supplementary_size: 0, ha
s_ownership: false, config: Configuration { suffix: FileName { value: FixedSizeByteString<255> { len: 8, data: ".dynamic" } }, prefix: FileName { value: FixedSizeByteStrin
g<255> { len: 5, data: "iox2_" } }, path: Path { value: FixedSizeByteString<255> { len: 14, data: "/tmp/iceoryx2/" } }, _data: PhantomData<iceoryx2::service::dynamic_confi
g::DynamicConfig> }, timeout: 500ms, initializer: , _phantom_data: PhantomData<iceoryx2::service::dynamic_config::DynamicConfig> }
| Failed to open  since the version number was not set - (it is not initialized after 500ms).

Which then lead to a failure when opening the dynamic service info and then the builder assumes the services is in a corrupted state. This comes only up with bazel, never occurs with cmake or with Rust (which has the same test)

The mechanism that seems to fail here is the concurrent dynamic storage creation/opening for the ipc::Service. To support concurrent creation/opening the creation must somehow tell the opener that the initialization is still in progress. This is done with two mechanisms:

1. The permission is set to write only as long as the memory is initializing.
2. The first 8 byte (or so) are zeroed by the OS and
3. when the initialization is finished the version number is written.
4. The permission is set to read/write

When the opener comes it first checks if it has read/write permissions, if not, initialization is still in progress. If it has read/write permissions it also checks the version number. If it is zero, still in initialization, if not zero it must match its own local version number.

[elfenpiff]

Okay, there was an actual bug in the dynamic storage posix shared memory implementation. When the creation process is still initializing the memory, the opener takes a COPY of the version number instead of a pointer to it and checks it until it becomes non-zero.

The thing is, this is a bug that should only occur on OSes that do not support adjusting the permissions of the shm during runtime like Mac OS and Windows and not linux.

And this also does not fix the failing test

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.92%. Comparing base (cd27eee) to head (b3dfa90). Report is 27 commits behind head on main.

Additional details and impacted files

[](https://app.codecov.io/gh/eclipse-iceoryx/iceoryx2/pull/472?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eclipse-iceoryx) ```diff @@ Coverage Diff @@ ## main #472 +/- ## ========================================== - Coverage 78.93% 78.92% -0.01% ========================================== Files 197 198 +1 Lines 23637 23627 -10 ========================================== - Hits 18657 18647 -10 Misses 4980 4980 ``` | [Files with missing lines](https://app.codecov.io/gh/eclipse-iceoryx/iceoryx2/pull/472?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eclipse-iceoryx) | Coverage Δ | | |---|---|---| | [iceoryx2-bb/elementary/src/package\_version.rs](https://app.codecov.io/gh/eclipse-iceoryx/iceoryx2/pull/472?src=pr&el=tree&filepath=iceoryx2-bb%2Felementary%2Fsrc%2Fpackage_version.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eclipse-iceoryx#diff-aWNlb3J5eDItYmIvZWxlbWVudGFyeS9zcmMvcGFja2FnZV92ZXJzaW9uLnJz) | `87.50% <100.00%> (+17.50%)` | :arrow_up: | | [...yx2-cal/src/dynamic\_storage/posix\_shared\_memory.rs](https://app.codecov.io/gh/eclipse-iceoryx/iceoryx2/pull/472?src=pr&el=tree&filepath=iceoryx2-cal%2Fsrc%2Fdynamic_storage%2Fposix_shared_memory.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eclipse-iceoryx#diff-aWNlb3J5eDItY2FsL3NyYy9keW5hbWljX3N0b3JhZ2UvcG9zaXhfc2hhcmVkX21lbW9yeS5ycw==) | `89.29% <100.00%> (-0.25%)` | :arrow_down: | ... and [4 files with indirect coverage changes](https://app.codecov.io/gh/eclipse-iceoryx/iceoryx2/pull/472/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eclipse-iceoryx)