Minirighi Code

- re-design the skel and prototypes of sys_open(), sys_close(), sys_read() and
sys_write()

- fix: correctly handle spurious IRQs

This also fixes a bug running minirighi on Bochs, that reported a lot of
messages like the following:

unhandled_interrupt(): unexepected IRQ number 007!

Bug reported by: Jon Rafkind <rafkind@...>

- fix: add an opportune suffix for the assembly instructions to specify
register size of atomic operations

- fix: missing variable declaration in lookup_chrdev() / lookup_blkdev()

/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.c: In function ‘lookup_chrdev’:
/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.c:109: error: ‘i’ undeclared (first use in this function)
/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.c:109: error: (Each undeclared identifier is reported only once
/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.c:109: error: for each function it appears in.)
/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.c: In function ‘lookup_blkdev’:
/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.c:203: error: ‘i’ undeclared (first use in this function)
make[2]: *** [/home/righiandr/projects/minirighi/trunk/os/fs/vfs/vfs.o] Error 1
make[1]: *** [kernel] Error 2
make: *** [world] Error 2

- implemented functions to get/lookup structures of registered character and
block devices

struct chrdev_struct *get_chrdev(unsigned int major);
struct chrdev_struct *lookup_chrdev(const char *name);
struct blkdev_struct *get_blkdev(unsigned int major);
struct blkdev_struct *lookup_blkdev(const char *name);

added lsdev userspace application, that use the lsdev() syscall

- implemented the lsdev() system call

This system call allows to print the list of block and character devices
registered in the kernel. This can be used to debug the device manager
subsystem for now, since no block or character device are registered in the
kernel yet.

- implemented an ugly (but working) way to execute files from ext2 filesystem

Now it is possible to execute files from an ext2 filesystem defined on the
hard-disk, using the syntax "ext2:filename" from the shell. This is just a
proof-of-concept for now and it would be really great to have a real block
device manager with a virtual filesystem layer ASAP.

implemented ext2_load_file()

- fix: set correct minirighi version in grub menu.

Remember to do this even if it's automatically fixed by make.