Historically, the page header provides 4-byte data alignment.
Therefore, unfortunately, the meta page data is also aligned on a 4-byte boundary, but contains 64-bit values.
This commit eliminates potentially unsafe access (SPARC, MIPS, etc) to these 64-bit values aligned on a 4-byte boundary.
Thus, a build with the `-fsanitize=undefined` now passes the tests both with CLANG 11 and GCC 10.
Change-Id: Ie441103e53ed96fd40507d8c0be0689e3fee69f5
Acknowledgements:
-----------------
- Jens Alfke (Mobile Architect at [Couchbase](https://www.couchbase.com/)) for [NimDBX](https://github.com/snej/nimdbx).
- Clément Renault (CTO at [MeiliSearch](https://www.meilisearch.com/)) for [mdbx-rs](https://github.com/Kerollmops/mdbx-rs).
- Alex Sharov (Go-Lang Teach Lead at [TurboGeth/Ethereum](https://ethereum.org/)) for an extreme test cases and bug reporting.
- George Hazan (CTO at [Miranda NG](https://www.miranda-ng.org/)) for bug reporting.
- [Positive Technologies](https://www.ptsecurity.com/) for funding and [The Standoff](https://standoff365.com/).
Added features:
---------------
- Provided package for [buildroot](https://buildroot.org/).
- Binding for Nim is [available](https://github.com/snej/nimdbx) now by Jens Alfke.
- Added `mdbx_env_delete()` for deletion an environment files in a proper and multiprocess-safe way.
- Added `mdbx_txn_commit_ex()` with collecting latency information.
- Fast completion pure nested transactions.
- Added `LIBMDBX_INLINE_API` macro and inline versions of some API functions.
- Added `mdbx_cursor_copy()` function.
- Extended tests for checking cursor tracking.
- Added `MDBX_SET_LOWERBOUND` operation for `mdbx_cursor_get()`.
Fixes:
------
- Fixed missing installation of `mdbx.h++`.
- Fixed use of obsolete `__noreturn`.
- Fixed use of `yield` instruction on ARM if unsupported.
- Added pthread workaround for buggy toolchain/cmake/buildroot.
- Fixed use of `pthread_yield()` for non-GLIBC.
- Fixed use of `RegGetValueA()` on Windows 2000/XP.
- Fixed use of `GetTickCount64()` on Windows 2000/XP.
- Fixed opening DB on a network shares (in the exclusive mode).
- Fixed copy&paste typos.
- Fixed minor false-positive GCC warning.
- Added workaround for broken `DEFINE_ENUM_FLAG_OPERATORS` from Windows SDK.
- Fixed cursor state after multimap/dupsort repeated deletes (https://github.com/erthink/libmdbx/issues/121).
- Added `SIGPIPE` suppression for internal thread during `mdbx_env_copy()`.
- Fixed extra-rare `MDBX_KEY_EXIST` error during `mdbx_commit()` (https://github.com/erthink/libmdbx/issues/131).
- Fixed spilled pages checking (https://github.com/erthink/libmdbx/issues/126).
- Fixed `mdbx_load` for 'plain text' and without `-s name` cases (https://github.com/erthink/libmdbx/issues/136).
- Fixed save/restore/commit of cursors for nested transactions.
- Fixed cursors state in rare/special cases (move next beyond end-of-data, after deletion and so on).
- Added workaround for MSVC 19.28 (Visual Studio 16.8) (but may still hang during compilation).
- Fixed paranoidal Clang C++ UB for bitwise operations with flags defined by enums.
- Fixed large pages checking (for compatibility and to avoid false-positive errors from `mdbx_chk`).
- Added workaround for Wine (https://github.com/miranda-ng/miranda-ng/issues/1209).
- Fixed `ERROR_NOT_SUPPORTED` while opening DB by UNC pathnames (https://github.com/miranda-ng/miranda-ng/issues/2627).
- Added handling `EXCEPTION_POSSIBLE_DEADLOCK` condition for Windows.
TODO for v0.9.3:
----------------
- Engage new terminology (https://github.com/erthink/libmdbx/issues/137).
- Rework/speedup the implementation of the dirty page list (lazy compactification, lazy sorting via merge).
- Resolve few TODOs (https://github.com/erthink/libmdbx/issues/123, https://github.com/erthink/libmdbx/issues/124, https://github.com/erthink/libmdbx/issues/127, https://github.com/erthink/libmdbx/issues/128, https://github.com/erthink/libmdbx/issues/132, https://github.com/erthink/libmdbx/issues/115).
- Finalize C++ API (few typos and trivia bugs are still likely for now).
- Packages for ROSA Linux, ALT Linux, Fedora/RHEL, Debian/Ubuntu.
Change-Id: I1f0ac4505052f169e36b326243e5d56497b9c037
Signed-off-by: Leonid Yuriev <leo@yuriev.ru>
Added features:
- Preliminary C++ API with support for C++17 polymorphic allocators.
- [Online C++ API reference](https://erthink.github.io/libmdbx/) by Doxygen.
- Quick reference for Insert/Update/Delete operations.
- Explicit `MDBX_SYNC_DURABLE` to sync modes for API clarity.
- Explicit `MDBX_ALLDUPS` and `MDBX_UPSERT` for API clarity.
- Support for read transactions preparation (`MDBX_TXN_RDONLY_PREPARE` flag).
- Support for cursor preparation/(pre)allocation and reusing (`mdbx_cursor_create()` and `mdbx_cursor_bind()` functions).
- Support for checking database using specified meta-page (see `mdbx_chk -h`).
- Support for turn to the specific meta-page after checking (see `mdbx_chk -h`).
- Support for explicit reader threads (de)registration.
- The `mdbx_txn_break()` function to explicitly mark a transaction as broken.
- Improved handling of corrupted databases by `mdbx_chk` utility and `mdbx_walk_tree()` function.
- Improved DB corruption detection by checking parent-page-txnid.
- Improved opening large DB (> 4Gb) from 32-bit code.
- Provided `pure-function` and `const-function` attributes to C API.
- Support for user-settable context for transactions & cursors.
- Revised API and documentation related to Handle-Slow-Readers callback feature.
Deprecated functions and flags:
- For clarity and API simplification the `MDBX_MAPASYNC` flag is deprecated.
Just use `MDBX_SAFE_NOSYNC` or `MDBX_UTTERLY_NOSYNC` instead of it.
- `MDBX_oom_func`, `mdbx_env_set_oomfunc()` and `mdbx_env_get_oomfunc()`
replaced with `MDBX_hsr_func`, `mdbx_env_get_hsr` and `mdbx_env_get_hsr()`.
Fixes:
- Fix `mdbx_strerror()` for `MDBX_BUSY` error (no error description is returned).
- Fix update internal meta-geo information in read-only mode (`EACCESS` or `EBADFD` error).
- Fix `mdbx_page_get()` null-defer when DB corrupted (crash by `SIGSEGV`).
- Fix `mdbx_env_open()` for re-opening after non-fatal errors (`mdbx_chk` unexpected failures).
- Workaround for MSVC 19.27 `static_assert()` bug.
- Doxygen descriptions and refinement.
- Update Valgrind's suppressions.
- Workaround to avoid infinite loop of 'nested' testcase on MIPS under QEMU.
- Fix a lot of typos & spelling (Thanks to Josh Soref for PR).
- Fix `getopt()` messages for Windows (Thanks to Andrey Sporaw for reporting).
- Fix MSVC compiler version requirements (Thanks to Andrey Sporaw for reporting).
- Workarounds for QEMU's bugs to run tests for cross-builded library under QEMU.
- Now C++ compiler optional for building by CMake.
TODO for next version(s):
- Rework/speedup the implementation of the dirty page list (lazy compactification, lazy sorting via merge).
- Finalize C++ API (few typos and trivia bugs are likely for now).
- Packages for ROSA Linux, ALT Linux, Fedora/RHEL, Debian/Ubuntu.
Change-Id: I668d77e4545d444b60708b8c64a66ce43b2c56a0
