is it possible to compile a kernel module on a live USB stick with Ubuntu 14.04 LTS? I have now tried for hours but all my attempts have failed.
What i've done. Installed the linux headers. Created a make file containing:
obj-m = hello.o
KVERSION = $(shell uname -r)
all:
make -C /lib/modules/$(KVERSION)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(KVERSION)/build M=$(PWD) clean
created a c file and added
#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_INFO */
#include <linux/init.h> /* Needed for the macros */
static int __init hello_start(void)
{
printk(KERN_INFO "Loading hello module...\n");
printk(KERN_INFO "Hello world\n");
return 0;
}
static void __exit hello_end(void)
{
printk(KERN_INFO "Goodbye Mr.\n");
}
module_init(hello_start);
module_exit(hello_end);
When i write "make hello" i get the responds:
ubuntu@ubuntu:~/Desktop/EmbeddedProgramming$ make hello
cc hello.c -o hello
hello.c:1:60: fatal error: linux/module.h: No such file or directory
#include <linux/module.h> /* Needed by all modules */
When i check uname -r i get back "3.16.0-30-generic". When i check the directory i can indeed find the module.h in that location. I got no idea why it say it cannot find the header file because it is there.
cc hello.c -o hellois the exact command being run, then it won't work. You need to use the-Iflag to specify that that directory should be included in the search for header files. Also, note that implicit rules are at play here. See this page.