Fix "cli_strdup(): s == NULL" error with clamonacc --wait

[rzvncj]

Issue occured when --ping # option was missing.

Fixes #443.

[rzvncj]

Looking at the code, I've seen this sort of thing happening a bit:

if (attempt_str) {
    free(attempt_str);
}

But free(NULL) should be perfectly safe (according to 7.20.3.2 of ISO-IEC 9899), so it seems like we could simplify those. Do we need to work with non-compliant compilers?

[rzvncj]

Is there anything I can do to fix the Windows PR check? I remember it didn't work on my previous (now merged) PR either.

[val-ms]

Is there anything I can do to fix the Windows PR check? I remember it didn't work on my previous (now merged) PR either.

Nothing you can easily do. I would not be surprised if we need to upgrade to a newer version of the lukka/run-cmake action to get it working again.

But the latest version has a different interface and also requires using a CMakePresets.json file.
Since we support all sorts of builds on Linux, Mac, Windows, and FreeBSD, setting up such a thing seems daunting. I need to do some reading and testing to try to solve that.

Don't worry about it for now. We do additional testing on Windows 10, 7, 32bit, and 64bit on our internal Jenkins and I will verify that all is well there for each PR. And also since this is only touching Clamonacc which doesn't exist for Windows -- even less need to worry. :)

[val-ms]

Thank you @rzvncj !!!

[val-ms]

Looking at the code, I've seen this sort of thing happening a bit:

if (attempt_str) {
    free(attempt_str);
}

But free(NULL) should be perfectly safe (according to 7.20.3.2 of ISO-IEC 9899), so it seems like we could simplify those. Do we need to work with non-compliant compilers?

Forgot to reply to this. It's fine to skip NULL checks for free(). I think we often do it habitually, but it doesn't really matter. Though there are some functions for cleaning up structures where you must do a NULL-check first. In that sense, it may be safer to be in the habit of doing NULL-checks. 🤷

[rzvncj]

Thank you @rzvncj !!!

Happy to help! 👍