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t_scan.c revision 1.2 
      1 /* $NetBSD: t_scan.c,v 1.2 2021/10/10 19:17:31 wiz Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2021 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_scan.c,v 1.2 2021/10/10 19:17:31 wiz Exp $");
     31 
     32 #include <sys/event.h>
     33 #include <sys/time.h>
     34 #include <sys/types.h>
     35 
     36 #include <err.h>
     37 #include <pthread.h>
     38 #include <stdio.h>
     39 #include <stdlib.h>
     40 #include <unistd.h>
     41 
     42 #include <atf-c.h>
     43 
     44 /*
     45  * Each kevent thread will make this many kevent() calls, and if it
     46  * achieves this mark, we assume the race condition has not occurred
     47  * the declare the test passes.
     48  */
     49 #define	NKEVENT_CALLS		10000
     50 
     51 static int kq;
     52 
     53 static void *
     54 kevent_thread(void *arg)
     55 {
     56 	struct timespec ts = { 0, 0 };
     57 	struct kevent event;
     58 	int rv, i;
     59 
     60 	for (i = 0; i < NKEVENT_CALLS; i++) {
     61 		rv = kevent(kq, NULL, 0, &event, 1, &ts);
     62 		if (rv < 0) {
     63 			i = rv;
     64 			break;
     65 		}
     66 		if (rv != 1) {
     67 			break;
     68 		}
     69 	}
     70 
     71 	return (void *)(intptr_t)i;
     72 }
     73 
     74 ATF_TC(scan1);
     75 ATF_TC_HEAD(scan1, tc)
     76 {
     77 	atf_tc_set_md_var(tc, "descr",
     78 	    "Exercises multi-threaded kevent() calls (PR kern/50094)");
     79 }
     80 
     81 ATF_TC_BODY(scan1, tc)
     82 {
     83 	pthread_t t1, t2;
     84 	void *v1, *v2;
     85 	intptr_t r1, r2;
     86 	struct kevent event;
     87 	int p[2];
     88 
     89 	ATF_REQUIRE(pipe(p) == 0);
     90 	ATF_REQUIRE((kq = kqueue()) >= 0);
     91 
     92 	EV_SET(&event, p[0], EVFILT_READ, EV_ADD, 0, 0, 0);
     93 	ATF_REQUIRE(kevent(kq, &event, 1, NULL, 0, NULL) == 0);
     94 	ATF_REQUIRE(write(p[1], p, 1) == 1);
     95 
     96 	ATF_REQUIRE(pthread_create(&t1, NULL, kevent_thread, NULL) == 0);
     97 	ATF_REQUIRE(pthread_create(&t2, NULL, kevent_thread, NULL) == 0);
     98 
     99 	ATF_REQUIRE(pthread_join(t1, &v1) == 0);
    100 	r1 = (intptr_t)v1;
    101 
    102 	ATF_REQUIRE(pthread_join(t2, &v2) == 0);
    103 	r2 = (intptr_t)v2;
    104 
    105 	ATF_REQUIRE(r1 >= 0);
    106 	ATF_REQUIRE(r2 >= 0);
    107 
    108 	ATF_REQUIRE(r1 == NKEVENT_CALLS);
    109 	ATF_REQUIRE(r2 == NKEVENT_CALLS);
    110 }
    111 
    112 ATF_TP_ADD_TCS(tp)
    113 {
    114 	ATF_TP_ADD_TC(tp, scan1);
    115 
    116 	return atf_no_error();
    117 }
    118