* * * * *
But it <EM>was</EM> possible …
The other day Rob [1] comes into my room. “I need some help,” he said. “I
made a mistake on my Sun box and I'm wondering if you could help me.”
Turns out Rob renamed a critical directory (/usr) and not only were most of
the commonly used programs stored under it, but so were all the runtime
libraries used by these commands, so nothing would run except for a few
statically compiled programs (programs that contained the libraries they
needed inside themselves). Nothing but the shell, mount, umount and fdisk
were available.
Now, I'm used to recovering with minimal commands [2] but there was no way to
rename a file, or change its permissions.
Heck, we were worse off than those in the classical Unix horror story [3].
Had I known SPARC assembly and how to call the kernel for Solaris 7, then
yes, we might have had a chance. Create the smallest binary to either create
a directory, or to rename a directory, and we'd be set. While it seems hard
to create a file without the normal commands one usually uses for such a
task, echo is a shell built-in, and using that with redirection and the
ability to specify arbitrary octal constants (with the “\nnn” notation
supported by the shell) and you have your program.
Okay, so you can't change the permissions on it, so pick some file you no
longer need with execute permissions and write over that, then you'll be able
to execute the hand-written program to get back into business.
Granted, that's if either of us new SPARC assembly and the executable format.
Since neither of us did, there wasn't much that could be done.
Well, maybe mounting the drives on another Solaris box, but Rob really didn't
care all that much since we was planning on reinstalling Solaris on that
system anyway.
But it was possible …
[1]
http://www.tragic-smurfs.com/
[2]
gopher://gopher.conman.org/0Phlog:1999/12/13.4
[3]
gopher://gopher.conman.org/0Phlog:2002/06/25/horror.txt
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