If a buffer smaller than Elf32_Ehdr was passed to Image, header()
would do an out-of-bounds read.
Make parse() check for that. Make most Image methods assert that the image
is_valid(). For that to work, set m_valid early in Image::parse()
instead of only at its end.
Also reorder a few things so that the fuzzer doesn't hit (valid)
assertions, which were harmless from a security PoV but which still
allowed userspace to crash the kernel with an invalid ELF file.
Make dbgprintf()s configurable at run time so that the fuzzer doesn't
produce lots of logspam.
This was supposed to be the foundation for some kind of pre-kernel
environment, but nobody is working on it right now, so let's move
everything back into the kernel and remove all the confusion.
functrace traces the function calls a program makes.
It's like strace, but for userspace.
It works by using Debugging functionality to insert breakpoints
at call&ret instructions.
