Samba development notes

Development documentation ¶

Links, 2, 3, 4…

https://wiki.samba.org/index.php/Development_Resources

Protocol documentation from Microsoft, now freely available: https://msdn.microsoft.com/en-us/openspecifications/dn646763.aspx Keyword to search in MSDN: WSSP (Workgroup Server Protocol Program)

TDB file format ¶

In short:

if TDB_FEATURE_FLAG_MUTEX:
    tdb_mutexes:
        tdb_header
        allrecords_mutex
        allrecord_lock          // the type of the lock, short int
        mutexes[hash_size + 1]  // free list + one for each bucket
tdb_header                      // repeated if there are mutexes; it's RO anyway
offsets[hash_size + 1]          // same as mutexes: #0 is for free list, then one for each bucket
records[...]:
    tdb_record
    key
    data

Records are aligned, so one cannot assume one record follows another.

Records are allocated 25% larger than strictly required, to reduce the fragmentation. So typically the size of the record is larger then sizeof(*rec) + rec->key_size + rec->data_size. It’s never smaller, obviously.

TDB file format is defined, in addition to the above map, by the following structs:

• tdb_header
• tdb_mutexes (not interesting)
• tdb_record

These structures are read directly from file into the memory (__attribute__((packed)), where are you?), and, if required, converted to respect the endianness.