fix(cmake): improve shared libs and pkg config files

[Apteryks]

What type of PR is this?

/kind bug

Any specific area of the project related to this PR?

/area build

/area libscap-engine-gvisor

/area libpman

/area libsinsp

What this PR does / why we need it:

It sanitizes the generated pkg-config files of libscap.pc and libsinsp.pc, and add missing includes needed to build as shared libraries.

Which issue(s) this PR fixes:

Fixes #1820

Special notes for your reviewer:

Also see #1825, which is not addressed by this PR but can be easily worked around.

Does this PR introduce a user-facing change?:

NONE

[poiana]

Welcome @Apteryks! It looks like this is your first PR to falcosecurity/libs 🎉

[Apteryks]

I've now successfully built sysdig against a shared library falcosecurity-libs distinct package with this series, on GNU Guix.

[FedeDP]

Hi! Thanks for this PR!
I will invoke our cmake experts for a review :)
To me, changes look good btw!

cc @federico-sysdig @geraldcombs

EDIT: i will edit the PR title and body to follow our template (as per our commit convention: https://github.com/falcosecurity/.github/blob/main/CONTRIBUTING.md#commit-convention)

[federico-sysdig]

It's an interesting PR and there's excellent work on the corrections for the generated pkgconfig files.
I do believe that something else is desirable for the management of the dependent libraries other than the proposed generator expressions.

I'm curious; I have tried to implement the ability to integrate falcosecurity/libs in a client project through find_package, which is a better, more CMake-oriented, way to use a library. This is not to say that pkgconfig should be left behind, just another option. What are your thoughts on that?

[Apteryks]

It's an interesting PR and there's excellent work on the corrections for the generated pkgconfig files. I do believe that something else is desirable for the management of the dependent libraries other than the proposed generator expressions.

I'll get to these in a bit.

I'm curious; I have tried to implement the ability to integrate falcosecurity/libs in a client project through find_package, which is a better, more CMake-oriented, way to use a library. This is not to say that pkgconfig should be left behind, just another option. What are your thoughts on that?

My immediate thought on this is that a FindFalcosecurityLibs.cmake or similarly named module implementing the logic forfind_package could be implemented viapkg_check_modules, with the obvious drawback that it adds a requirement on a pkg-config binary being available in the environment. Whatever the implementation detail chosen for an eventual CMake-based find_package module for this project, I think it can and should remain a distinct effort from this PR, which focuses on improving the pkg-config generated files :-).

[federico-sysdig]

Whatever the implementation detail chosen for an eventual CMake-based find_package module for this project, I think it can and should remain a distinct effort from this PR, which focuses on improving the pkg-config generated files :-).

Of course, I wasn't suggesting to change the scope of this PR.

[geraldcombs]

The "build-shared-libs-macos-amd64" job is failing because CFlags in libscap.pc no longer includes -I/opt/homebrew/include:

In file included from /tmp/libs-test/include/falcosecurity/libsinsp/sinsp.h:45:
In file included from /tmp/libs-test/include/falcosecurity/libscap/scap.h:66:
/tmp/libs-test/include/falcosecurity/libscap/uthash_ext.h:24:10: fatal error: 'uthash.h' file not found
#include "uthash.h"
         ^~~~~~~~~~

[Apteryks]

The "build-shared-libs-macos-amd64" job is failing because CFlags in libscap.pc no longer includes -I/opt/homebrew/include:

In file included from /tmp/libs-test/include/falcosecurity/libsinsp/sinsp.h:45:
In file included from /tmp/libs-test/include/falcosecurity/libscap/scap.h:66:
/tmp/libs-test/include/falcosecurity/libscap/uthash_ext.h:24:10: fatal error: 'uthash.h' file not found
#include "uthash.h"
         ^~~~~~~~~~

The Cflags of the libscap.pc file shouldn't have changed; I've only added two new entries to them. For example, on my machine, the old copy (master) looks like:

 $ cat ./libscap/libscap.pc 
prefix=${pcfiledir}/../..
libdir=${prefix}/lib64
includedir=${prefix}/include

Name: libscap
Description: lib for System CAPture
Version: 0.0.0

Libs: -L${libdir} -L/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/lib -L/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/lib -L/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/lib -L/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/lib -L/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/lib -lscap -lz -lprotobuf -ljsoncpp -lscap_engine_nodriver -lscap_engine_test_input -lscap_engine_source_plugin -lscap_engine_kmod -lscap_engine_bpf -lelf -lscap_engine_modern_bpf -lpman
Cflags: -I${includedir}/falcosecurity/libscap

With this change it now reads:

$ cat ../build/libscap/libscap.pc
prefix=/usr/local
libdir=${prefix}/lib64
includedir=${prefix}/include

Name: libscap
Description: lib for System CAPture
Version: 0.0.0

Requires: zlib
Libs: -L${libdir} -L{libdir}/falcosecurity/libscap  -lscap -lscap_engine_nodriver -lscap_engine_test_input -lscap_engine_source_plugin -lscap_engine_kmod -lscap_engine_bpf -lscap_engine_modern_bpf
Cflags: -I${includedir}/falcosecurity/libscap -I${includedir}/falcosecurity/driver -I${includedir}/falcosecurity

Probably this header was found via libsinsp.pc, which was capturing a lot of build-specific, non-installed directories, which I think shouldn't be baked in the generated .pc file.

Previously, it looked like:

$ cat ./libsinsp/libsinsp.pc 
prefix=${pcfiledir}/../..
libdir=${prefix}/lib64
includedir=${prefix}/include

Name: libsinsp
Description: lib for System INSPection
Version: 0.0.0

Requires: libscap
Libs: -L${libdir} -lsinsp -L/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/lib -lz -lcurl -ljsoncpp -lre2 -lcares -lgRPC::grpc++ -lgRPC::grpc -lgRPC::gpr -lprotobuf -lcares -lrt -lanl -lssl -lcrypto -ldl -lpthread
Cflags: -I${includedir}/falcosecurity/libsinsp -I/home/maxim/src/falcosecurity-libs -I/home/maxim/src/falcosecurity-libs/userspace -I/home/maxim/src/falcosecurity-libs/userspace/libscap -I/home/maxim/src/falcosecurity-libs/build_orig -I/home/maxim/src/falcosecurity-libs/build_orig/driver/src -I/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/include/tbb -I/gnu/store/65iv1fc7z68cammywngh0dn5995ylbmk-profile/include

Now, it looks like:

$ cat ../build/libsinsp/libsinsp.pc 
prefix=/usr/local
libdir=${prefix}/lib64
includedir=${prefix}/include

Name: libsinsp
Description: lib for System INSPection
Version: 0.0.0

Requires: libscap jsoncpp libcares gpr grpc grpc++ protobuf libcrypto libssl
Requires.private: libcurl re2 tbb
Libs: -L${libdir} -lsinsp -lrt -lanl -ldl -lpthread
Cflags: -I${includedir}/falcosecurity/libsinsp -I${includedir}/falcosecurity/driver -I${includedir}/falcosecurity

[leogr]

Any updates on this?

Since 0.20 is too close, moving this to
/milestone 0.21.0

[Apteryks]

test-scap-{amd64,arm64} tests are failing with:

make[3]: *** No rule to make target 'protobuf-prefix/src/protobuf/target/lib/libprotobuf.a', needed by 'test/libscap/libscap_test'. Stop.

Care to give it a look @Apteryks ?

Sorry for the long wait, I'll take a look at it now.

[FedeDP]

No problem :)

[Apteryks]

Lot's have changed (for the better it seems); there's less in this PR following a rebase. I've been conservative in my edits in the hope that even the most exotic platforms shouldn't be impacted in the CI; let's see.

[Apteryks]

Lot's have changed (for the better it seems); there's less in this PR following a rebase. I've been conservative in my edits in the hope that even the most exotic platforms shouldn't be impacted in the CI; let's see.

Actually, the pkg-config files Libs: entries are back to contain a bit too much, which is correct for the static build case but leads to overlinking on GNU/Linux, which is not fatal. I'm not sure how to fix this cleanly for both builds to pass, so I guess I'll leave it at that.

[Apteryks]

Actually, the pkg-config files Libs: entries are back to contain a bit too much, which is correct for the static build case but leads to overlinking on GNU/Linux, which is not fatal. I'm not sure how to fix this cleanly for both builds to pass, so I guess I'll leave it at that.

The latest revision resolves that. It's a bit hacky in the add_pkgconfig_library macro, but to be honest, it already was :-). The result looks great and I could build sysdig (which a few edits there to support the latest falcosecurity-libs).

I'm sharing the content of the freshly built pkg-config files, for a build configured with the flags: cmake -DBUILD_SHARED_LIBS=ON -DUSE_BUNDLED_DEPS=OFF -DCMAKE_INSTALL_PREFIX=$PWD/install "-DBUILD_DRIVER=OFF" "-DENABLE_DKMS=OFF" "-DBUILD_LIBSCAP_MODERN_BPF=ON":

$ cat install/lib64/pkgconfig/libscap.pc
prefix=/home/maxim/src/falcosecurity-libs/buildc/install
libdir=${prefix}/lib64
includedir=${prefix}/include/falcosecurity

Name: libscap
Description: lib for System CAPture
Version: 0.21.0-19+d07beb8

# Note: jsoncpp and protobuf are required by scap_engine_gvisor, which
# currently lacks its own pkg-config file.
Requires: jsoncpp libpman protobuf
Requires.private: zlib
Libs: -L${libdir}  -lscap -lscap_event_schema -lscap_platform -lscap_engine_nodriver -lscap_engine_test_input -lscap_engine_source_plugin -lscap_engine_kmod -lscap_event_schema -lscap_platform -lscap_engine_bpf -lscap_event_schema -lscap_platform -lelf -lscap_engine_modern_bpf -lscap_engine_gvisor -lscap_event_schema
Cflags: -I${includedir} -I${includedir}/libscap -I${includedir}/driver -I/gnu/store/4b30xdqjj81dcyl5p518rp33vlm2iag8-profile/include

$ cat install/lib64/pkgconfig/libsinsp.pc
prefix=/home/maxim/src/falcosecurity-libs/buildc/install
libdir=${prefix}/lib64
includedir=${prefix}/include/falcosecurity

Name: libsinsp
Description: lib for System INSPection
Version: 0.21.0-19+d07beb8

Requires: libscap jsoncpp libcares gpr grpc grpc++ protobuf libcares libcrypto libssl
Requires.private: libcurl re2 tbb
Libs: -L${libdir}  -lsinsp
Cflags: -I${includedir} -I${includedir}/libsinsp -I${includedir}/driver -I/gnu/store/4b30xdqjj81dcyl5p518rp33vlm2iag8-profile/include/tbb -I/gnu/store/4b30xdqjj81dcyl5p518rp33vlm2iag8-profile/include

$ cat install/lib64/pkgconfig/libpman.pc
prefix=/home/maxim/src/falcosecurity-libs/buildc/install
libdir=${prefix}/lib64
includedir=${prefix}/include

Name: libpman
Description: Utility library for BPF probes
Version: 0.21.0-19+d07beb8

Requires: libbpf zlib
Libs: -L${libdir} -lpman -lscap_event_schema -lscap_platform
Cflags: -I${includedir}

[Apteryks]

I think that's ready to be reviewed again.

[Apteryks]

Only the sinsp example with pkg-config test appears to fail when building as a shared library on Linux and MacOS. I'll look into it; perhaps the install directory needs to be added to PKG_CONFIG_PATH.

[Apteryks]

These tests pass locally, on my Guix System. I needed to use lib64 instead of lib in the PKG_CONFIG_PATH (and LIBRARY_PATH) though, so perhaps the paths in the ci.yml file need a similar adjustment?

[Apteryks]

Phew. I think my last push hopefully addresses the remaining test failures. I've made the Requires and Requires.private for libscap conditionally computed like for libsinsp, and dropped what seemed like an extraneous protobuf link dependency I had added to the scap unit test.