Don't be so silent about missing libraries

[nyh]

Currently, when we try to load a library needed (in DT_NEEDED) by a shared object, and can't find it, we print the error with

    debug("could not load %s\n", lib);

This message is not visible unless the "--verbose" (run.py -V) option is used. In the past this used to be deliberate - a lot of shared objects had a bunch of silly requirements that weren't really needed, and these messages were distracting. But I'm starting to think that these messages are important. We often get an application crashing on "failed looking up symbol", and it turns out this is not a symbol that OSv should have contained, but rather something from a library we failed to load because it was missing on the image or something. See for example issue #601.

One trivial fix is to change debug() to debug_always(). Maybe the message should also include the wording "Warning" or something.

[jeffreyxie0615]

Hi! My partner and I are from UT Austin as part of their Virtualization class, and we were wondering if we could tackle this issue as a first issue?

[nyh]

Hi! My partner and I are from UT Austin as part of their Virtualization class, and we were wondering if we could tackle this issue as a first issue?

Sure, go ahead :-) This is an easy issue but can get you introduced on how to build OSv, how to build it with an application, how to run it, and so on. If you don't know how to start please ask a question on the osv mailing list (osv-dev at googlegroups.com) and I'll try to answer.