What is an SDB file?

Question

In the abstract, I'm just wondering what an SDB file does and what role it plays. I see Radare2 is using them.. Here are some of the SDB files I have under ./libr/bin/d/dll/, what do these do?

./libr/bin/d/dll/csmfpapi.sdb
./libr/bin/d/dll/atl.sdb
./libr/bin/d/dll/msvbvm60.sdb
./libr/bin/d/dll/msi.sdb
./libr/bin/d/dll/mfc90u.sdb
./libr/bin/d/dll/msvbvm50.sdb
./libr/bin/d/dll/dsound.sdb
./libr/bin/d/dll/mfc71.sdb
./libr/bin/d/dll/olepro32.sdb

Answer 1

SDB stands for String Database.

sdb is a simple string key/value database based on cdb disk storage and supports JSON and arrays introspection.

You can see the SDB commands listed with the k command,

|Usage: k[s] [key[=value]]Sdb Query
| k foo=bar                 set value
| k foo                     show value
| k                         list keys
| ko [file.sdb] [ns]        open file into namespace
| kd [file.sdb] [ns]        dump namespace to disk
| ks [ns]                   enter the sdb query shell
| k anal/meta/*             ist kv from anal > meta namespaces
| k anal/**                 list namespaces under anal
| k anal/meta/meta.0x80404  get value for meta.0x80404 key

There's a whole post about it in radare2 blog, check it out here.
You can read more about it in this link from radare2's repository.
There's also a short, and not so detailed, chapter about it in r2book.

---

Edit: You added another question so I'll expand my answer accordingly.
These sdbfiles contain function names (DLL's exports) and their equivalent ordinals for each dll in ./libr/bin/d/dll/. Each file contains a key-value line in this format:

ordinal_num=export_name
another_ordinal_num=another_export_name

So, if we'll take msi.dll from the list you've mentioned, its sdb file will look like this:

...
232=Migrate10CachedPackagesW
1=MsiAdvertiseProductA
223=MsiAdvertiseProductExA
224=MsiAdvertiseProductExW
2=MsiAdvertiseProductW
...

These files are then compiled by MakeFile. To add sdb files for DLL you can follow "sdb_ordinal.md" article from radare2 docs.