Using codeql for Cross Compiled environment

[axlev]

Hi,
Is cross compilation supported for C/C++?
Trying to run the database creation either with direct or indirect build ends up with:

/bin/sh: /lib/i386-linux-gnu/libc.so.6: version `GLIBC_2.17' not found (required by codeql/tools/linux64/lib32trace.so)

The libc installed both for 32 and 64 bit architecture on the host machine:
ldd --version
ldd (Ubuntu GLIBC 2.35-0ubuntu3.3) 2.35

Is that possible that libc for the target machine not found ? The target is i386 / x64 as well, but the rootfs is different.

Thanks!
Alex

[aibaars]

Cross compilation should be possible. The error message normally means that your libc is too old, so I'm a bit surprised to see this error message when you seem to have version 2.35 installed. Could you double check the stuff that is installed in the rootfs? Also make sure that the target is actually glibc based and not based on something like muslc .

[axlev]

The target is based on glibc, the version is actually higher than 2.17:

root@localhost:~# ldd --version
ldd (Debian GLIBC 2.19-18+deb8u10) 2.19

@aibaars Is the error message relates to host or target glibc version ?
Thanks!

[aibaars]

That's a lot older than 2.35 but still newer than the required 2.17 . Do you have multiple versions of glibc installed? Have you inspected /lib/i386-linux-gnu/libc.so.6 (both host and target) with ldd?

Could you also have a look in the database/log/build-tracer.log file? Hopefully, there is some information in there to help diagnose what is going wrong.

[aibaars]

@aibaars Is the error message relates to host or target glibc version ?

It depends, it's probably a mix. CodeQL uses LD_PRELOAD to inject its libARCHtrace.so libraries into all binaries that run as part of the build to intercept the compiler invocations (gcc and friends). Likely the main build script is running on the host, while the actual gcc calls are likely the binaries from the target.

[axlev]

We have a single repo from which few different images are created 2 of them seem to have ver 2.13 - indeed older than 2.17. However there is also image with libc 2.19.
Q1: are libc older than 2.17 not supported ? Many embedded systems are still running it as far as I know.
Q2: Is it possible to skip the files with unsupported libc and create database for supported only ? I think it is possible to do it indirectly by using start-tracing and end-tracing, is that the right way to address it ?
Thanks, @aibaars !

[aibaars]

Q1: are libc older than 2.17 not supported ? Many embedded systems are still running it as far as I know.

That's right. The CodeQL tracer requires glibc >= 2.17 to run. I guess things could work fine if you run the build on a modern OS but compile against the header files of the embedded system.

Q2: Is it possible to skip the files with unsupported libc and create database for supported only ? I think it is possible to do it indirectly by using start-tracing and end-tracing, is that the right way to address it ?

I think the easiest would be to only run the build commands for the supported targets.