Re: compat_linux failures due to execve, openat, etc.

[Kevin Bloom <ktnb%posteo.net@localhost>]

Robert Swindells <rjs%fdy2.co.uk@localhost> wrote:

> 
> Kevin Bloom <ktnb%posteo.net@localhost> wrote:
> > I've been wanting to try out NetBSD compat_linux(8) for a long time
> > and I've finally had a situation that seems like a good candidate for
> > testing it out. I've done the setup as explained in the man page,
> > however, it appears that there is some issue with finding some key
> > functions, specifically: execve, access, open, stat64, statfs,
> > and connect. When I view the ktrace(1) dump
> > I see lines like:
> >
> > 13390  13390 nix-env  CALL execve(0x7f7fffffdec0, 0x7f7fff223a90, 0x7f7fff223ab0)
> > 13390  13390 nix-env  NAMI "/nix/store/${hash1}-nix-2.32.2/bin/nix-env"
> > 13390  13390 nix-env  NAMI "/emul/linux"
> > 13390  13390 nix-env  NAMI "/emul/linux/nix/store/${hash2}-glibc-2.40-66/lib/ld-linux-x86-64.so.2"a
> > 13390  13390 nix-env  NAMI "/nix/store/${hash2}-glibc-2.40-66/lib/ld-linux-x86-64.so.2"
> > 13390  13390 nix-env  EMUL "linux"
> > 13390  13390 nix-env  RET execve -1 errno -2 No such file or directory
> >
> > When I look in the glibc directory I do see that shared lib in there
> > so I'm confused why it's saying it's missing.
> >
> > I honestly don't no much about how the compat layer works other than
> > what is in the wiki and man page. Any ideas to debug this more?
> >
> > PS: I know that nix doesn't work on NetBSD but I have a situation
> > where being able to ues nix on NetBSD for _linux_ programs would be
> > handy.
> 
> What is the hash1 & hash2 for?

I'm not totally sure why nix does that. Every program in nix is given
a hash. My guess would be to avoid confusion with the naming of the
program or something.

> Are they really part of the names of actual files or is some part of
> the nix environment expected to expand them to something else?

I'm nix will just symlink in $HOME/.nix-profile/bin to the
/nix/store/ hashed version of /bin. In other words, if you had a
program called foo you'd have:
$ ls -l $HOME/.nix-profile/bin
$HOME/.nix-profile/bin/foo -> /nix/store/hash-foo-1.2.3/bin/foo