/*-
 * Copyright (c) 2018 Thomas Munro
 * All rights reserved.
 *
 * 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 AUTHOR 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 AUTHOR 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>
#include <assert.h>
#include <atf-c.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sys/procctl.h>
#include <sys/ptrace.h>
#include <sys/signal.h>
#include <sys/types.h>

static void
dummy_signal_handler(int signum)
{
}

ATF_TC_WITHOUT_HEAD(arg_validation);
ATF_TC_BODY(arg_validation, tc)
{
        int signum;
        int rc;

        /* bad signal */
        signum = 8888;
        rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
        ATF_CHECK_EQ(-1, rc);
        ATF_CHECK_EQ(EINVAL, errno);

        /* bad id type */
        signum = SIGINFO;
        rc = procctl(8888, 0, PROC_PDEATHSIG_CTL, &signum);
        ATF_CHECK_EQ(-1, rc);
        ATF_CHECK_EQ(EINVAL, errno);

        /* bad id (pid that doesn't match mine or zero) */
        signum = SIGINFO;
        rc = procctl(P_PID, (((getpid() + 1) % 10) + 100),
            PROC_PDEATHSIG_CTL, &signum);
        ATF_CHECK_EQ(-1, rc);
        ATF_CHECK_EQ(EINVAL, errno);

        /* null pointer */
        signum = SIGINFO;
        rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, NULL);
        ATF_CHECK_EQ(-1, rc);
        ATF_CHECK_EQ(EFAULT, errno);

        /* good (pid == 0) */
        signum = SIGINFO;
        rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
        ATF_CHECK_EQ(0, rc);

        /* good (pid == my pid) */
        signum = SIGINFO;
        rc = procctl(P_PID, getpid(), PROC_PDEATHSIG_CTL, &signum);
        ATF_CHECK_EQ(0, rc);

        /* check that we can read the signal number back */
        signum = 0xdeadbeef;
        rc = procctl(P_PID, 0, PROC_PDEATHSIG_STATUS, &signum);
        ATF_CHECK_EQ(0, rc);
        ATF_CHECK_EQ(SIGINFO, signum);
}

ATF_TC_WITHOUT_HEAD(fork_no_inherit);
ATF_TC_BODY(fork_no_inherit, tc)
{
        int status;
        int signum;
        int rc;

        /* request a signal on parent death in the parent */
        signum = SIGINFO;
        rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);

        rc = fork();
        ATF_REQUIRE(rc != -1);
        if (rc == 0) {
                /* check that we didn't inherit the setting */
                signum = 0xdeadbeef;
                rc = procctl(P_PID, 0, PROC_PDEATHSIG_STATUS, &signum);
                assert(rc == 0);
                assert(signum == 0);
                _exit(0);
        }

        /* wait for the child to exit successfully */
        waitpid(rc, &status, 0);
        ATF_CHECK_EQ(0, status);
}

ATF_TC_WITHOUT_HEAD(exec_inherit);
ATF_TC_BODY(exec_inherit, tc)
{
        int status;
        int rc;

        rc = fork();
        ATF_REQUIRE(rc != -1);
        if (rc == 0) {
                char exec_path[1024];
                int signum;

                /* compute the path of the helper executable */
                snprintf(exec_path, sizeof(exec_path), "%s/pdeathsig_helper",
                         atf_tc_get_config_var(tc, "srcdir"));

                /* request a signal on parent death and register a handler */
                signum = SIGINFO;
                rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
                assert(rc == 0);

                /* execute helper program: it asserts that it has the setting */
                rc = execl(exec_path, exec_path, NULL);
                assert(rc == 0);
                _exit(0);
        }

        /* wait for the child to exit successfully */
        waitpid(rc, &status, 0);
        ATF_CHECK_EQ(0, status);
}

ATF_TC_WITHOUT_HEAD(signal_delivered);
ATF_TC_BODY(signal_delivered, tc)
{
        sigset_t sigset;
        int signum;
        int rc;
        int pipe_ca[2];
        int pipe_cb[2];
        char buffer;

        rc = pipe(pipe_ca);
        ATF_REQUIRE(rc == 0);
        rc = pipe(pipe_cb);
        ATF_REQUIRE(rc == 0);

        rc = fork();
        ATF_REQUIRE(rc != -1);
        if (rc == 0) {
                rc = fork();
                assert(rc >= 0);
                if (rc == 0) {
                        /* process C */
                        signum = SIGINFO;

                        /* block signals so we can handle them synchronously */
                        rc = sigfillset(&sigset);
                        assert(rc == 0);
                        rc = sigprocmask(SIG_SETMASK, &sigset, NULL);
                        assert(rc == 0);

                        /* register a dummy handler or the kernel will not queue it */
                        signal(signum, dummy_signal_handler);

                        /* request a signal on death of our parent B */
                        rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
                        assert(rc == 0);

                        /* tell B that we're ready for it to exit now */
                        rc = write(pipe_cb[1], ".", 1);
                        assert(rc == 1);

                        /* wait for B to die and signal us... */
                        signum = 0xdeadbeef;
                        rc = sigwait(&sigset, &signum);
                        assert(rc == 0);
                        assert(signum == SIGINFO);

                        /* tell A the test passed */
                        rc = write(pipe_ca[1], ".", 1);
                        assert(rc == 1);
                        _exit(0);
                }

                /* process B */

                /* wait for C to tell us it is ready for us to exit */
                rc = read(pipe_cb[0], &buffer, 1);
                assert(rc == 1);

                /* now we exit so that C gets a signal */
                _exit(0);
        }
        /* process A */

        /* wait for C to tell us the test passed */
        rc = read(pipe_ca[0], &buffer, 1);
        ATF_CHECK_EQ(1, rc);
}

ATF_TC_WITHOUT_HEAD(signal_delivered_ptrace);
ATF_TC_BODY(signal_delivered_ptrace, tc)
{
        sigset_t sigset;
        int signum;
        int rc;
        int pipe_ca[2];
        int pipe_db[2];
        int pipe_cd[2];
        char buffer;
        int status;

        rc = pipe(pipe_ca);
        ATF_REQUIRE(rc == 0);
        rc = pipe(pipe_db);
        ATF_REQUIRE(rc == 0);
        rc = pipe(pipe_cd);
        assert(rc == 0);

        rc = fork();
        ATF_REQUIRE(rc != -1);
        if (rc == 0) {
                pid_t c_pid;

                /* process B */

                rc = fork();
                assert(rc >= 0);
                if (rc == 0) {
                        /* process C */
                        signum = SIGINFO;

                        /* block signals so we can handle them synchronously */
                        rc = sigfillset(&sigset);
                        assert(rc == 0);
                        rc = sigprocmask(SIG_SETMASK, &sigset, NULL);
                        assert(rc == 0);

                        /* register a dummy handler or the kernel will not queue it */
                        signal(signum, dummy_signal_handler);

                        /* request a signal on parent death and register a handler */
                        rc = procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
                        assert(rc == 0);

                        rc = write(pipe_cd[1], "x", 1);
                        assert(rc == 1);

                        /* wait for B to die and signal us... */
                        signum = 0xdeadbeef;
                        rc = sigwait(&sigset, &signum);
                        assert(rc == 0);
                        assert(signum == SIGINFO);

                        /* tell A the test passed */
                        rc = write(pipe_ca[1], ".", 1);
                        assert(rc == 1);
                        _exit(0);
                }
                c_pid = rc;


                /* fork another process to ptrace C */
                rc = fork();
                assert(rc >= 0);
                if (rc == 0) {

                        /* process D */
                        rc = ptrace(PT_ATTACH, c_pid, 0, 0);
                        assert(rc == 0);

                        waitpid(c_pid, &status, 0);
                        assert(WIFSTOPPED(status));
                        assert(WSTOPSIG(status) == SIGSTOP);

                        rc = ptrace(PT_CONTINUE, c_pid, (caddr_t) 1, 0);
                        assert(rc == 0);

                        rc = read(pipe_cd[0], &buffer, 1);
                        assert(rc == 1);

                        /* tell B that we're ready for it to exit now */
                        rc = write(pipe_db[1], ".", 1);
                        assert(rc == 1);

                        waitpid(c_pid, &status, 0);
                        assert(WIFSTOPPED(status));
                        assert(WSTOPSIG(status) == SIGINFO);

                        rc = ptrace(PT_CONTINUE, c_pid, (caddr_t) 1,
                                    WSTOPSIG(status));
                        assert(rc == 0);

                        waitpid(c_pid, &status, 0);
                        if (!WIFEXITED(status))
                                ptrace(PT_DETACH, c_pid, 0, 0);

                        _exit(0);
                }

                /* wait for D to tell us it is ready for us to exit */
                rc = read(pipe_db[0], &buffer, 1);
                assert(rc == 1);

                /* now we exit so that C gets a signal */
                _exit(0);
        }

        /* process A */

        /* wait for C to tell us the test passed */
        rc = read(pipe_ca[0], &buffer, 1);
        ATF_CHECK_EQ(1, rc);
}

ATF_TP_ADD_TCS(tp)
{
        ATF_TP_ADD_TC(tp, arg_validation);
        ATF_TP_ADD_TC(tp, fork_no_inherit);
        ATF_TP_ADD_TC(tp, exec_inherit);
        ATF_TP_ADD_TC(tp, signal_delivered);
        ATF_TP_ADD_TC(tp, signal_delivered_ptrace);
        return (atf_no_error());
}