Linker issues when linking with LLD 18

[dlots]

LLD 18 enables --no-undefined flag by default, producing errors like this:

ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_aead_getdata' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_aead_outbuflen' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_init' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_destroy' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_setkey' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_setpubkey' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_encrypt' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_decrypt' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_sign' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_verify' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_init_enc' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_init_dec' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_init_sgn' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_init_vfy' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_update' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_update_last' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.12.0' to symbol 'kcapi_akcipher_stream_op' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.14.0' to symbol 'kcapi_akcipher_encrypt_aio' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.14.0' to symbol 'kcapi_akcipher_decrypt_aio' failed: symbol not defined
ld.lld: error: version script assignment of 'LIBKCAPI_0.14.0' to symbol 'kcapi_akcipher_sign_aio' failed: symbol not defined
ld.lld: error: too many errors emitted, stopping now (use --error-limit=0 to see all errors)

Need to add --undefined-version flag to allow undefined again.

[smuellerDD]

Am Montag, 17. Februar 2025, 19:57:41 CET schrieb Dmitry Sazanov: Hi Dmitry,

dlots left a comment (smuellerDD/libkcapi#191) Also, could you please explain to me, why version script need to include deprecated symbols that were scraped from the code completely? Is this backwards compatibility requirement?

First of all, thanks for the report. The symbols of kcapi_aead_getdata and kcapi_aead_outbuflen are indeed an oversight and should be removed. However, the akcipher API is not: It can be conditionally enabled and compiled with the --enable-lib-asym configure flag. Other parts of the library can be disabled with the respective --disable flags. As I am unaware of how to tell the version script to conditionally ignore some flags, I am not sure how to properly solve the issue. Any ideas? Ciao Stephan

[dlots]

From top of my head, you could have conditionally enabled symbols in a separate files and compose a final version script in automake, adding necessary extra symbols depending on which options are enabled.

[smuellerDD]

Am Dienstag, 18. Februar 2025, 14:53:26 CET schrieb Dmitry Sazanov: Hi Dmitry,

dlots left a comment (smuellerDD/libkcapi#191) From top of my head, you could have conditionally enabled symbols in a separate files and compose a final version script in automake, adding necessary extra symbols depending on which options are enabled.

Hm, I do not think I would want that considering you have 7 options that can selectively disable API parts where you can mix-n-match them. Each of those options effectively allow/prevent the compilation of one C file in lib/ Furthermore, I am also working on another library, leancrypto, which has many many more options to disable features and thus prevent APIs to compile. Granted, I do not yet have a version.lds there, but I plan to once I figured out how to do that with Meson. Ciao Stephan