replace shell call with a file based detection + user opt in/out

[DRoppelt]

#9956

[DRoppelt]

I have no idea how to add a test that could cover this part.

    for(File f : allFilesInLib) {
      if(f.getPath().startsWith("/lib/libc.musl")) return true;
    }
    return false;

I have however verified it manually on an alpine and ubuntu image of adoptium

Alpine

➜  rocksdb git:(main) ✗ docker run -it --entrypoint sh eclipse-temurin:17.0.3_7-jdk-alpine
/ # jshell
May 10, 2022 8:03:23 PM java.util.prefs.FileSystemPreferences$1 run
INFO: Created user preferences directory.
|  Welcome to JShell -- Version 17.0.3
|  For an introduction type: /help intro

jshell> boolean resolveIsMuslLibc() {
   ...>     File[] allFilesInLib = new File("/lib/").listFiles();
   ...>     if(allFilesInLib == null) return false;
   ...>     for(File f : allFilesInLib) {
   ...>       if(f.getPath().startsWith("/lib/libc.musl")) return true;
   ...>     }
   ...>     return false;
   ...>   }
|  created method resolveIsMuslLibc()

jshell> resolveIsMuslLibc()
$2 ==> true

jshell>

Ubuntu

➜  rocksdb git:(main) ✗ docker run -it --entrypoint sh eclipse-temurin:17.0.3_7-jdk
# jshell
May 10, 2022 7:23:08 PM java.util.prefs.FileSystemPreferences$1 run
INFO: Created user preferences directory.
|  Welcome to JShell -- Version 17.0.3
|  For an introduction type: /help intro
jshell> boolean resolveIsMuslLibc() {
   ...>     File[] allFilesInLib = new File("/lib/").listFiles();
   ...>     if(allFilesInLib == null) return false;
   ...>     for(File f : allFilesInLib) {
   ...>       if(f.getPath().startsWith("/lib/libc.musl")) return true;
   ...>     }
   ...>     return false;
   ...>   }
|  created method resolveIsMuslLibc()

jshell> resolveIsMuslLibc()
$6 ==> false

[riversand963]

Hi @adamretter, could you take a look at this sometime?

[adamretter]

@DRoppelt I created a new PR which incorporates your work and extends it here - #10889. My goal was to add adopt your feature for allowing the user to specify an option, and your search for musl libc files in lib, whilst preserving the existing approach and adding a small optimisation.

If you are happy with my (our combined PR) in #10889 let me know, and I suggest we close this PR.

[DRoppelt]

@adamretter LGTM, thank you. For my usecase I would like to see the filebased approach first but I understand that preserving the previous behavior is more important. In a security rescricted env, a failed call to shell might still be flagged. But I can opt-out via the env-var so all good for me 👍