/* $NetBSD: t_sig.c,v 1.5 2024/07/10 22:03:59 rillig Exp $ */

/*-
* Copyright (c) 2002, 2008, 2021 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Luke Mewburn and Jaromir Dolecek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__COPYRIGHT("@(#) Copyright (c) 2008\
The NetBSD Foundation, inc. All rights reserved.");
__RCSID("$NetBSD: t_sig.c,v 1.5 2024/07/10 22:03:59 rillig Exp $");

#include <sys/event.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/wait.h>

#include <inttypes.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <atf-c.h>

#include "h_macros.h"

#define NSIGNALS 5

ATF_TC(sig);
ATF_TC_HEAD(sig, tc)
{
       atf_tc_set_md_var(tc, "descr", "Checks EVFILT_SIGNAL");
}
ATF_TC_BODY(sig, tc)
{
       struct timespec timeout;
       struct kfilter_mapping km;
       struct kevent event[1];
       char namebuf[32];
       pid_t pid, child;
       int kq, n, num, status;

       pid = getpid();
       (void)printf("my pid: %d\n", pid);

       /* fork a child to send signals */
       RL(child = fork());
       if (child == 0) {
               int i;
               (void)sleep(2);
               for(i = 0; i < NSIGNALS; ++i) {
                       (void)kill(pid, SIGUSR1);
                       (void)sleep(2);
               }
               _exit(0);
               /* NOTREACHED */
       }

       RL(kq = kqueue());

       (void)strlcpy(namebuf, "EVFILT_SIGNAL", sizeof(namebuf));
       km.name = namebuf;
       RL(ioctl(kq, KFILTER_BYNAME, &km));
       (void)printf("got %d as filter number for `%s'.\n", km.filter, km.name);

       /* ignore the signal to avoid taking it for real */
       REQUIRE_LIBC(signal(SIGUSR1, SIG_IGN), SIG_ERR);

       event[0].ident = SIGUSR1;
       event[0].filter = km.filter;
       event[0].flags = EV_ADD | EV_ENABLE;

       RL(kevent(kq, event, 1, NULL, 0, NULL));

       (void)sleep(1);

       timeout.tv_sec = 1;
       timeout.tv_nsec = 0;

       for (num = 0; num < NSIGNALS; num += n) {
               struct timeval then, now, diff;

               RL(gettimeofday(&then, NULL));
               RL(n = kevent(kq, NULL, 0, event, 1, &timeout));
               RL(gettimeofday(&now, NULL));
               timersub(&now, &then, &diff);

               (void)printf("sig: kevent returned %d in %lld.%06ld\n",
                   n, (long long)diff.tv_sec, (long)diff.tv_usec);

               if (n == 0)
                       continue;

               (void)printf("sig: kevent flags: 0x%x, data: %" PRId64 " (# "
                   "times signal posted)\n", event[0].flags, event[0].data);
       }

       (void)waitpid(child, &status, 0);
       (void)printf("sig: finished successfully\n");
}

/*
* This test case exercises code paths in the kernel that KASSERT()
* some assumptions about EVFILT_SIGNAL and EVFILT_PROC implementation
* details.
*/
ATF_TC(sig_and_proc);
ATF_TC_HEAD(sig_and_proc, tc)
{
       atf_tc_set_md_var(tc, "descr",
           "Validates implementation detail assumptions about "
           "EVFILT_SIGNAL and EVFILT_PROC");
}
ATF_TC_BODY(sig_and_proc, tc)
{
       struct kevent events[3];
       pid_t pid;
       int kq;

       pid = fork();
       ATF_REQUIRE(pid != -1);

       if (pid == 0) {
               /*
                * Child: create a kqueue and attach signal knotes
                * to curproc->p_klist.
                */
               kq = kqueue();
               ATF_REQUIRE(kq >= 0);

               ATF_REQUIRE(signal(SIGUSR1, SIG_IGN) != SIG_ERR);
               ATF_REQUIRE(signal(SIGUSR2, SIG_IGN) != SIG_ERR);

               EV_SET(&events[0], SIGUSR1, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
               EV_SET(&events[1], SIGUSR2, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);

               ATF_REQUIRE(kevent(kq, events, 2, &events[2], 1, NULL) == 1);
               ATF_REQUIRE(events[2].filter == EVFILT_SIGNAL);
               ATF_REQUIRE(events[2].ident == SIGUSR1);

               /*
                * When we exit here, the kernel will close all of
                * its file descriptors (including our kq), which
                * will in turn remove the signal notes from
                * curproc->p_klist.
                *
                * Then, later on, the kernel will post a NOTE_EXIT
                * on our parent's kqueue using the proc note that
                * our parent attached to (our) curproc->p_klist.
                * That code path KASSERT()s that the signal knotes
                * have already been removed.
                */
               _exit(0);
       }

       /*
        * Parent: create a kqueue and attach a proc note to
        * child->p_klist.
        */
       kq = kqueue();
       ATF_REQUIRE(kq >= 0);

       EV_SET(&events[0], pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);

       ATF_REQUIRE(kevent(kq, events, 1, NULL, 0, NULL) == 0);

       /* Ensure we never see stale data. */
       memset(events, 0, sizeof(events));

       /* Signal child to exit. */
       ATF_REQUIRE(kill(pid, SIGUSR1) == 0);

       ATF_REQUIRE(kevent(kq, NULL, 0, events, 1, NULL) == 1);
       ATF_REQUIRE(events[0].filter == EVFILT_PROC);
       ATF_REQUIRE(events[0].ident == (uintptr_t)pid);
       ATF_REQUIRE(events[0].fflags == NOTE_EXIT);
}

ATF_TP_ADD_TCS(tp)
{
       ATF_TP_ADD_TC(tp, sig);
       ATF_TP_ADD_TC(tp, sig_and_proc);

       return atf_no_error();
}