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      1 /* $NetBSD: t_sigaltstack.c,v 1.2 2020/05/01 21:35:30 christos Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2020 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __RCSID("$NetBSD: t_sigaltstack.c,v 1.2 2020/05/01 21:35:30 christos Exp $");
     31 
     32 #include <signal.h>
     33 #include <stdbool.h>
     34 
     35 #include <atf-c.h>
     36 
     37 #include "h_macros.h"
     38 
     39 static stack_t sigstk;
     40 static bool handler_called;
     41 static bool handler_use_altstack;
     42 
     43 static void
     44 handler(int signo __unused)
     45 {
     46 	char sp[128];
     47 
     48 	handler_called = true;
     49 
     50 	/* checking if the stack pointer is within the range of altstack */
     51 	if ((char *)sigstk.ss_sp <= sp &&
     52 	    ((char *)sigstk.ss_sp + sigstk.ss_size) > sp)
     53 		handler_use_altstack = true;
     54 	else
     55 		handler_use_altstack = false;
     56 }
     57 
     58 ATF_TC(sigaltstack_onstack);
     59 ATF_TC_HEAD(sigaltstack_onstack, tc)
     60 {
     61 	atf_tc_set_md_var(tc, "descr",
     62 	    "Checks for using signal stack with SA_ONSTACK");
     63 }
     64 
     65 ATF_TC_BODY(sigaltstack_onstack, tc)
     66 {
     67 	struct sigaction sa;
     68 	int i;
     69 
     70 	/* set a signal handler use alternative stack */
     71 	memset(&sigstk, 0, sizeof(sigstk));
     72 	sigstk.ss_sp = malloc(SIGSTKSZ);
     73 	ATF_REQUIRE(sigstk.ss_sp != NULL);
     74 	sigstk.ss_size = SIGSTKSZ;
     75 	sigstk.ss_flags = 0;
     76 	ATF_REQUIRE(sigaltstack(&sigstk, 0) == 0);
     77 
     78 	sigemptyset(&sa.sa_mask);
     79 	sa.sa_handler = handler;
     80 	sa.sa_flags = SA_ONSTACK;
     81 	sigaction(SIGUSR1, &sa, NULL);
     82 
     83 	/* test several times */
     84 	for (i = 1; i <= 5; i++) {
     85 		handler_called = false;
     86 		kill(getpid(), SIGUSR1);
     87 
     88 		if (!handler_called)
     89 			atf_tc_fail("signal handler wasn't called (count=%d)", i);
     90 		if (!handler_use_altstack)
     91 			atf_tc_fail("alternative stack wasn't used (count=%d)", i);
     92 	}
     93 }
     94 
     95 ATF_TP_ADD_TCS(tp)
     96 {
     97 	ATF_TP_ADD_TC(tp, sigaltstack_onstack);
     98 
     99 	return atf_no_error();
    100 }
    101