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// 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");
}
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