fix(cmake): fixed 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]

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[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

[FedeDP]

/milestone 0.18.0