realksh.c - A shell for running Kernel-mode C code

realksh.c

realksh.c is an interactive shell that runs C source code. A line of input is handled as a line in module_init() function, and the resulting C code is compiled to build a kernel module. The module is then inserted into the kernel, and removed from the kernel. kernel message output prepended with KMSG: is copied to standard out for convenience, so that functions like printk can be used for easy debugging.

If a line starting with # such as #include <stdio.h> is entered, it is added to every code after that at the start of sourcecode.

The list of such lines can be seen with ##

The following is an example session

$ sudo ./realksh.c
REAL ksh: printk ("hello\n");
  Building modules, stage 2.
KMSG: <4>hello

REAL ksh: printk ("%x\n", mfmsr()); Building modules, stage 2. KMSG: <4>9032

REAL ksh: printk ("%x\n", mfspr(SPRN_MMCR0)); Building modules, stage 2. KMSG: <4>0

REAL ksh:

The following is how the C code looks like.

#include <linux/module.h>
#include <linux/init.h>
MODULE_AUTHOR("dancerj");
MODULE_DESCRIPTION("....");
MODULE_LICENSE("GPL");
static int __init realkshmod2_init(void)
{
input-line
return 0; 
}
static void __exit realkshmod2_cleanup(void)
{
}
module_init(realkshmod2_init);
module_exit(realkshmod2_cleanup);

Junichi Uekawa (dancer@debian.org)

Upstream page is available at http://www.netfort.gr.jp/~dancer/software/

binfmtc-interpreter(1), realcsh.c(1)