/*-
 * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * PR:  272585
 * Test provided by John F. Carr
 */

#include <sys/systm.h>
#include <sys/mman.h>
#include <vm/vm_param.h>

#include <atf-c.h>
#include <signal.h>
#include <unistd.h>

static void
sigsegv_handler(int sig __unused)
{

        atf_tc_fail("Invalid stack protection mode after grows");
}

ATF_TC_WITHOUT_HEAD(mprotect_exec_test);
ATF_TC_BODY(mprotect_exec_test, tc)
{
        long pagesize;
        char *addr, *guard;
        size_t alloc_size;

        signal(SIGSEGV, sigsegv_handler);

        pagesize = sysconf(_SC_PAGESIZE);
        ATF_REQUIRE(pagesize > 0);

        alloc_size = SGROWSIZ * 2;
        addr = mmap(NULL, alloc_size, PROT_READ | PROT_WRITE,
            MAP_STACK | MAP_PRIVATE | MAP_ANON, -1, 0);
        ATF_REQUIRE(addr != MAP_FAILED);

        /*
         * Change prot of the last page in the mmaped stack area.
         */
        guard = addr + alloc_size - SGROWSIZ;
        ATF_REQUIRE(mprotect(guard, pagesize, PROT_NONE) == 0);

        ((volatile char *)guard)[-1];
}

ATF_TP_ADD_TCS(tp)
{

        ATF_TP_ADD_TC(tp, mprotect_exec_test);

        return (atf_no_error());
}