Re: Executable shared object

[Segher Boessenkool <segher@xxxxxxxxx>]

Paolo Massimino wrote:
> Hi All!
> I have a problem. I need to build a sherd object that, like libc do, can 
> print some information when you execute it like a normal executable.
> Anyone can help me ?
> Thank you
> Paolo

Assuming you are on an ELF GNU/Linux system...

Link normally, but add -Wl,-e,the_name_of_your_entry_point
for example this Makefile fragment:

--- 8< ---
dop.so: dop.c
	gcc -Wall -W -fPIC -shared -o dop.so dop.c -lc -Wl,-e,my_main
--- 8< ---

and add code like this:

--- 8< ---
const char my_interp[] __attribute__((section(".interp"))) = "/lib/ld.so.1";

void my_main(int argc, char **argv)
{
	int i;

	printf("Called as:");
	for (i = 0; i < argc; i++)
		printf(" %s", argv[i]);
	printf("\n");

	exit(0);
}
--- 8< ---


Have fun,

Segher