Re: error on startup with latest guile-vm

[Andy Wingo <wingo@pobox.com>]

Hi,

On Wed 15 Oct 2008 07:17, "Julian Graham" <joolean@gmail.com> writes:

> Next up on the list of stupid questions: I was able to compile one of
> my modules, but the resulting .go file got created with (what looks
> like) a weirdly restrictive umask -- mode 600, and not, say, 664 or
> 644.  Did I do something wrong?

Nope, it's just abuse of POSIX -- we create a temporary file then relink
it if the compilation succeeded. Temp files have those perms by default.
Patches welcome, to fix this to use the user's umask, to
call-with-output-file/atomic in (system base compile).

As an aside, it used to be that the file was truncated then rewritten.
This was bad. That part of the kernel is notoriously buggy. More
relevantly, truncating an mmapped file will cause SIGBUS, which we must
avoid. It seems that we are fine with our mmap strategy -- like with ELF
files -- but we have to take some care.

While I'm rambling, I was looking at the ELF format today, inspired by
razor (an *incredibly* fast package manager --
http://github.com/krh/razor/wikis/razor-design), and we really should do
more of that style of coding. Specifically regarding ELF, we should be
able to dump tagged SCM values into an ELF file, which would help with
undumping. And we should be able to write native code to ELF files. But
this is all future work. There is lots of exciting stuff to do in this
regard.

Andy
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