/*
 * Copyright (c) 2004, 2014-2015 Todd C. Miller <millert@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifndef INFTIM
#define INFTIM  -1
#endif

void usage(void);
void sigalrm(int);
void sigusr1(int);
void dopoll(pid_t, int, int, char *, int);
void doselect(pid_t, int, int, int);
void runtest(char *, int, int);
void eoftest(char *, int, int);

#if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) || \
    defined(__linux__)
extern char *__progname;
#else
char *__progname;
#endif

/*
 * Test FIFOs and poll(2) both with an emtpy and full FIFO.
 */
int
main(int argc, char **argv)
{
        struct sigaction sa;
#if !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__NetBSD__) && \
    !defined(__linux__)
        __progname = argv[0];
#endif
        if (argc != 2)
                usage();

        /* Just want EINTR from SIGALRM */
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;
        sa.sa_handler = sigalrm;
        sigaction(SIGALRM, &sa, NULL);

        /* SIGUSR1 is used for synchronization only. */
        sa.sa_flags = SA_RESTART;
        sa.sa_handler = sigusr1;
        sigaction(SIGUSR1, &sa, NULL);

        runtest(argv[1], 0, 0);
        runtest(argv[1], 0, INFTIM);
        runtest(argv[1], O_NONBLOCK, 0);
        runtest(argv[1], O_NONBLOCK, INFTIM);
        eoftest(argv[1], O_NONBLOCK, INFTIM);

        exit(0);
}

void
runtest(char *fifo, int flags, int timeout)
{
        ssize_t nread;
        int fd;
        char buf[BUFSIZ];

        (void)unlink(fifo);
        if (mkfifo(fifo, 0644) != 0) {
                printf("mkfifo %s: %s\n", fifo, strerror(errno));
                exit(1);
        }

        /* Note: O_RDWR not required by POSIX */
        alarm(2);
        if ((fd = open(fifo, O_RDWR | flags)) == -1) {
                printf("open %s: %s\n", fifo, strerror(errno));
                exit(1);
        }
        alarm(0);
        (void)unlink(fifo);
        printf("\nOpened fifo %s%s\n", fifo,
            (flags & O_NONBLOCK) ? " (nonblocking)" : "");

        printf("\nTesting empty FIFO:\n");
        dopoll(-1, fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
        dopoll(-1, fd, POLLIN, "POLLIN", timeout);
        dopoll(-1, fd, POLLOUT, "POLLOUT", timeout);
        dopoll(-1, fd, 0, "(none)", timeout);
        doselect(-1, fd, fd, timeout);
        doselect(-1, fd, -1, timeout);
        doselect(-1, -1, fd, timeout);
        doselect(-1, -1, -1, timeout);

        if (write(fd, "test", 4) != 4) {
                printf("write error: %s\n", strerror(errno));
                exit(1);
        }

        printf("\nTesting full FIFO:\n");
        dopoll(-1, fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
        dopoll(-1, fd, POLLIN, "POLLIN", timeout);
        dopoll(-1, fd, POLLOUT, "POLLOUT", timeout);
        dopoll(-1, fd, 0, "(none)", timeout);
        doselect(-1, fd, fd, timeout);
        doselect(-1, fd, -1, timeout);
        doselect(-1, -1, fd, timeout);
        doselect(-1, -1, -1, timeout);

        if ((nread = read(fd, buf, sizeof(buf))) <= 0) {
                printf("read error: %s\n", (nread == 0) ? "EOF" : strerror(errno));
                exit(1);
        }
        buf[nread] = '\0';
        printf("\treceived '%s' from FIFO\n", buf);
}

pid_t
eof_writer(const char *fifo, int flags)
{
        int fd;
        pid_t pid;
        sigset_t mask, omask;

        /* Block SIGUSR1 (in child). */
        sigemptyset(&mask);
        sigaddset(&mask, SIGUSR1);
        sigprocmask(SIG_BLOCK, &mask, &omask);

        switch ((pid = fork())) {
        case -1:
                printf("fork: %s\n", strerror(errno));
                return -1;
        case 0:
                /* child */
                break;
        default:
                /* parent */
                sigprocmask(SIG_SETMASK, &omask, NULL);
                return pid;
        }

        /* Wait for reader. */
        sigemptyset(&mask);
        sigsuspend(&mask);
        sigprocmask(SIG_SETMASK, &omask, NULL);

        /* connect to FIFO. */
        alarm(2);
        fd = open(fifo, O_WRONLY | flags);
        alarm(0);
        if (fd == -1) {
                printf("open %s O_WRONLY: %s\n", fifo, strerror(errno));
                return -1;
        }

        /*
         * We need to give the reader time to call poll() or select()
         * before we close the fd.  This is racey...
         */
        usleep(100000);
        close(fd);
        _exit(0);
}

void
eoftest(char *fifo, int flags, int timeout)
{
        ssize_t nread;
        int fd = -1, pass, status;
        pid_t writer;
        char buf[BUFSIZ];

        /*
         * Test all combinations of select and poll.
         */
        for (pass = 0; pass < 16; pass++) {
                /*
                 * We run each test twice, once with a fresh fifo,
                 * and once with a reused one.
                 */
                if ((pass & 1) == 0) {
                        if (fd != -1)
                                close(fd);
                        (void)unlink(fifo);
                        if (mkfifo(fifo, 0644) != 0) {
                                printf("mkfifo %s: %s\n", fifo, strerror(errno));
                                exit(1);
                        }

                        /* XXX - also verify that we get alarm for O_RDWR */
                        alarm(2);
                        if ((fd = open(fifo, O_RDONLY | flags, 0644)) == -1) {
                                printf("open %s: %s\n", fifo, strerror(errno));
                                exit(1);
                        }
                        alarm(0);

                        printf("\nOpened fifo for reading %s%s\n", fifo,
                            (flags & O_NONBLOCK) ? " (nonblocking)" : "");
                }

                printf("\nTesting EOF FIFO behavior (pass %d):\n", pass);

                /*
                 * The writer will sleep for a bit to give the reader time
                 * to call select() before anything has been written.
                 */
                writer = eof_writer(fifo, flags);
                if (writer == -1)
                        exit(1);

                switch (pass) {
                case 0:
                case 1:
                    dopoll(writer, fd, POLLIN|POLLOUT, "POLLIN|POLLOUT", timeout);
                    break;
                case 2:
                case 3:
                    dopoll(writer, fd, POLLIN, "POLLIN", timeout);
                    break;
                case 4:
                case 5:
                    dopoll(writer, fd, POLLOUT, "POLLOUT", timeout);
                    break;
                case 6:
                case 7:
                    dopoll(writer, fd, 0, "(none)", timeout);
                    break;
                case 8:
                case 9:
                    doselect(writer, fd, fd, timeout);
                    break;
                case 10:
                case 11:
                    doselect(writer, fd, -1, timeout);
                    break;
                case 12:
                case 13:
                    doselect(writer, -1, fd, timeout);
                    break;
                case 14:
                case 15:
                    doselect(writer, -1, -1, timeout);
                    break;
                }
                wait(&status);
                if ((nread = read(fd, buf, sizeof(buf))) < 0) {
                        printf("read error: %s\n", strerror(errno));
                        exit(1);
                }
                buf[nread] = '\0';
                printf("\treceived %s%s%s from FIFO\n", nread ? "'" : "",
                    nread ? buf : "EOF", nread ? "'" : "");
        }
        close(fd);
        (void)unlink(fifo);
}

void
dopoll(pid_t writer, int fd, int events, char *str, int timeout)
{
        struct pollfd pfd;
        int nready;

        pfd.fd = fd;
        pfd.events = events;

        printf("\tpoll %s, timeout=%d\n", str, timeout);
        pfd.events = events;
        if (writer != -1)
                kill(writer, SIGUSR1);
        alarm(2);
        nready = poll(&pfd, 1, timeout);
        alarm(0);
        if (nready < 0) {
                printf("poll: %s\n", strerror(errno));
                return;
        }
        printf("\t\t%d fd(s) ready%s", nready, nready ? ", revents ==" : "");
        if (pfd.revents & POLLIN)
                printf(" POLLIN");
        if (pfd.revents & POLLOUT)
                printf(" POLLOUT");
        if (pfd.revents & POLLERR)
                printf(" POLLERR");
        if (pfd.revents & POLLHUP)
                printf(" POLLHUP");
        if (pfd.revents & POLLNVAL)
                printf(" POLLNVAL");
        printf("\n");
}

void
doselect(pid_t writer, int rfd, int wfd, int timeout)
{
        struct timeval tv, *tvp;
        fd_set *rfds = NULL, *wfds = NULL;
        int nready, maxfd;

        if (timeout == INFTIM)
                tvp = NULL;
        else {
                tv.tv_sec = timeout / 1000;
                tv.tv_usec = (timeout % 1000) * 1000;
                tvp = &tv;
        }
        maxfd = rfd > wfd ? rfd : wfd;
        if (rfd != -1) {
                rfds = calloc(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
                if (rfds == NULL) {
                        printf("unable to allocate memory\n");
                        exit(1);
                }
                FD_SET(rfd, rfds);
        }
        if (wfd != -1) {
                wfds = calloc(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
                if (wfds == NULL) {
                        printf("unable to allocate memory\n");
                        exit(1);
                }
                FD_SET(wfd, wfds);
        }

        printf("\tselect%s%s, timeout=%d\n", rfds ? " read" : "",
            wfds ? " write" : rfds ? "" : " (none)", timeout);
        if (writer != -1)
                kill(writer, SIGUSR1);
        alarm(2);
        nready = select(maxfd + 1, rfds, wfds, NULL, tvp);
        alarm(0);
        if (nready < 0) {
                printf("select: %s\n", strerror(errno));
                goto cleanup;
        }
        printf("\t\t%d fd(s) ready", nready);
        if (rfds != NULL && FD_ISSET(rfd, rfds))
                printf(", readable");
        if (wfds != NULL && FD_ISSET(wfd, wfds))
                printf(", writeable");
        printf("\n");
cleanup:
        free(rfds);
        free(wfds);
}

void
sigalrm(int dummy)
{
        /* Just cause EINTR */
        return;
}

void
sigusr1(int dummy)
{
        return;
}

void
usage(void)
{
        fprintf(stderr, "usage: %s fifoname\n", __progname);
        exit(1);
}