Hi libtool devs, Historically, rpm has included its own OpenPGP implementation. This implementation is incomplete and buggy, and the maintainers of rpm have decided that they would like to use a different OpenPGP implementation.
There are two major constraints. Because rpm's OpenPGP API is public, it must be preserved until the next soname bump. And, the OpenPGP backend should be pluggable. https://github.com/rpm-software-management/rpm/issues/1935 https://github.com/rpm-software-management/rpm/issues/1978#issuecomment-1080606598 I've recently created an alternate OpenPGP backend for rpm based on Sequoia PGP. Sequoia is written in Rust. I created a Rust shim (rpm-sequoia), which implements rpm's OpenPGP API: https://gitlab.com/sequoia-pgp/rpm-sequoia In other words, I've created a library called librpm_sequoia, which provides symbols like pgpPubkeyKeyID, which were previously provided by librpmio.so directly. That is, using the internal OpenPGP implementation, librpmio.so includes these symbols: $ objdump -T /usr/lib/x86_64-linux-gnu/librpmio.so.9.1.2 | grep pgp | head -n2 0000000000018330 g DF .text 0000000000000101 Base pgpValString 0000000000019200 g DF .text 000000000000005c Base pgpPubkeyKeyID When using my replacement backend, librpmio.so must continue to provide these symbols. In this way, some program foo that links against librpmio (i.e., has a DT_NEEDED for librpmio) should be able to use our Sequoia-based librpmio without relinking. Similarly, a program foo that is linked against the Sequoia variant of librpmio should still be usable with a variant of librpmio that uses the internal OpenPGP implementation. Unfortunately, I can't figure out how to get librpmio to reexport librpm_sequoia's symbols. Currently, foo needs to be relinked explicitly against librpm_sequoia.so. For instance, here you can see that rpmpgpcheck is now explicitly linked against librpmio.la *and* librpm_sequoia.so: rpmpgpcheck_LDADD = ../rpmio/librpmio.la \ @WITH_RPM_SEQUOIA_LIB@ https://github.com/rpm-software-management/rpm/blob/master/tests/Makefile.am#L15 Before it was enough to just link against librpmio.la. Yes, librpmio is linked against librpm_sequoia: librpmio_la_LIBADD = \ ... \ @WITH_RPM_SEQUOIA_LIB@ \ https://github.com/rpm-software-management/rpm/blob/master/rpmio/Makefile.am#L39 And the resulting librpmio does have a DT_NEEDED on librpm_sequoia: $ objdump -p .libs/librpmio.so | grep sequoia NEEDED librpm_sequoia.so And the symbols are mentioned: $ objdump -T .libs/librpmio.so | grep pgp | head -n2 0000000000000000 DF *UND* 0000000000000000 Base pgpSignatureType 0000000000000000 DF *UND* 0000000000000000 Base pgpPubkeyKeyID This appears to be sufficient to resolve librpmio's use of librpm_sequoia's symbols. But, when linking a program like rpmpgpcheck against librpmio.la, the linker does not consider librpm_sequoia.so's symbols unless it is explicitly linked against against librpm_sequoia.so. That is, changing rpmpgpcheck to only link against librpmio: rpmpgpcheck_LDADD = ../rpmio/librpmio.la results in the following errors: libtool: link: cc -shared -fPIC -DPIC .libs/argv.o .libs/more....o -Wl,--whole-archive ../misc/.libs/libmisc.a -Wl,--no-whole-archive -L/tmp/rpm-sequoia/release -lrpm_sequoia -lbz2 -lz -lpopt -llzma -llua5.4 -ldl -lpthread -g -O2 -Wl,-soname -Wl,librpmio.so.9 -o .libs/librpmio.so.9.3.0 ... libtool: link: cc -Wall -Wpointer-arith -Wmissing-prototypes -Wstrict-prototypes -fno-strict-aliasing -fno-strict-overflow -fno-delete-null-pointer-checks -Wempty-body -g -O2 -o .libs/rpmpgpcheck rpmpgpcheck.o ../rpmio/.libs/librpmio.so -ldl -lpthread -Wl,-rpath -Wl,/home/us/neal/work/pep/rpm/b/../i/lib /usr/bin/ld: rpmpgpcheck.o: undefined reference to symbol 'pgpDigParamsFree' /usr/bin/ld: /tmp/rpm-sequoia/release/librpm_sequoia.so: error adding symbols: DSO missing from command line My understanding is that this error message means: the symbol pgpDigParamsFree is needed, it was not found in any of the mentioned libraries, but it is present in librpm_sequoia.so, so link to that. My conclusion is that I somehow need to get librpmio to reexport librpm_sequoia's symbols. Despite spending hours searching, I haven't figured out how to do that. I'd appreciate any hints that might lead me to a solution. Thanks, :) Neal
