/*      $OpenBSD: exec_self.c,v 1.3 2024/01/23 10:27:12 anton Exp $     */
/*
 *      Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <sys/types.h>
#include <sys/mman.h>

struct {
        const char pad1[256*1024];      /* avoid read-ahead. */
        const char string[256*1024];    /* at least one page */
        const char pad2[256*1024];      /* avoid read-behind. */
} const blob __attribute__((section(".openbsd.mutable"))) = {
        "padding1",
        "the_test",
        "padding2"
};

int
main(int argc, char **argv)
{
        int pgsz = getpagesize();
        vaddr_t va, off;

        if (argc > 1) {
                return (0);
        }
        va = (vaddr_t)&blob;
        off = va & (pgsz - 1);

        /* Make sure that nothing in the "blob" is cached. */
        if (madvise((void *)(va - off), sizeof(blob) + (off > 0 ? pgsz : 0),
            MADV_FREE))
                err(1, "madvise");

        if (execl(argv[0], argv[0], &blob.string, (char *)NULL))
                err(1, "execl");

        /* NOTREACHED */
        return (1);
}