liblogdb – A save and simple append only key-/value-database format

What is liblogdb?

Logdb is a simple and save append only key/value database. Ideal for crypto key storages and similar applications.

• pure C89
• no dependencies
• high test coverage
• memory leak free (valgrind check during CI)

Data format

The data serialization format was designed to allow detection of all types of file corruption. Because logdb only appends data, possible file corruptions should be reduced. In case of a corrupt file, the static record header-magic as well as the per-record 16byte sha256 allows to identify records.

[8 bytes]          per file magic 0xF9, 0xAA, 0x03, 0xBA
[int32_t/4 bytes]  version number
[int32_t/4 bytes]  version flags
---- records
  [8 bytes]          static per record magic 0x88, 0x61, 0xAD, 0xFC, 0x5A, 0x11, 0x22, 0xF8
  [16 bytes]         partial sha256 hash (first 16 bytes) of the record body
  ---- record-body start ----
  [1 byte]           record type (0 = write | 1 = erase)
  [varint]           length of the key
  [variable]         key data
  [varint]           length of the value
  [variable]         value data
  ---- record-body end ----
  [16 bytes]         partial sha256 of *all data* up to this point in logdb
  ---- record end ---
  ---- more records

How to Build

./autogen.sh
./configure
make check

Who is using logdb

• libbtc, https://github.com/libbtc/libbtc