// SPDX-License-Identifier: GPL-2.0

/*
 * Copyright 2017 John Sperbeck
 *
 * Test that an access to a mapped but inaccessible area causes a SEGV and
 * reports si_code == SEGV_ACCERR.
 */

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/mman.h>
#include <assert.h>
#include <ucontext.h>

#include "utils.h"

static bool faulted;
static int si_code;

static void segv_handler(int n, siginfo_t *info, void *ctxt_v)
{
        ucontext_t *ctxt = (ucontext_t *)ctxt_v;
        struct pt_regs *regs = ctxt->uc_mcontext.regs;

        faulted = true;
        si_code = info->si_code;
        regs->nip += 4;
}

int test_segv_errors(void)
{
        struct sigaction act = {
                .sa_sigaction = segv_handler,
                .sa_flags = SA_SIGINFO,
        };
        char c, *p = NULL;

        p = mmap(NULL, getpagesize(), 0, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
        FAIL_IF(p == MAP_FAILED);

        FAIL_IF(sigaction(SIGSEGV, &act, NULL) != 0);

        faulted = false;
        si_code = 0;

        /*
         * We just need a compiler barrier, but mb() works and has the nice
         * property of being easy to spot in the disassembly.
         */
        mb();
        c = *p;
        mb();

        FAIL_IF(!faulted);
        FAIL_IF(si_code != SEGV_ACCERR);

        faulted = false;
        si_code = 0;

        mb();
        *p = c;
        mb();

        FAIL_IF(!faulted);
        FAIL_IF(si_code != SEGV_ACCERR);

        return 0;
}

int main(void)
{
        return test_harness(test_segv_errors, "segv_errors");
}