/* $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();
}