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      1 /*	$NetBSD: cmd_pollpal.c,v 1.1 2020/04/30 00:48:10 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2020 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: cmd_pollpal.c,v 1.1 2020/04/30 00:48:10 christos Exp $");
     31 
     32 #include <sys/mman.h>
     33 
     34 #include <errno.h>
     35 #include <err.h>
     36 #include <fcntl.h>
     37 #include <poll.h>
     38 #include <signal.h>
     39 #include <stdio.h>
     40 #include <stdlib.h>
     41 #include <stdarg.h>
     42 #include <string.h>
     43 #include <unistd.h>
     44 
     45 #define BUFFLEN 100
     46 #define TIMEOUT 10000
     47 
     48 static int fd;
     49 
     50 static __dead __printflike(2, 3) void
     51 done(int e, const char *msg, ...)
     52 {
     53 	if (msg) {
     54 		va_list ap;
     55 
     56 		va_start(ap, msg);
     57 		verr(e, msg, ap);
     58 		/*NOTREACHED*/
     59 		va_end(ap);
     60 	}
     61 	exit(e);
     62 }
     63 
     64 static __dead void
     65 handler(int sig)
     66 {
     67 	done(EXIT_SUCCESS, NULL);
     68 }
     69 
     70 static const char dev[] = "/dev/pollpal";
     71 static const char wbuf[] = "abcdefghijklmnopqrstuvwxyz";
     72 
     73 int
     74 main(int argc, char **argv)
     75 {
     76 	struct pollfd fds;
     77 	ssize_t ret;
     78 	size_t i;
     79 	char rbuf[BUFFLEN];
     80 
     81 	setprogname(argv[0]);
     82 
     83 	fd = open(dev, O_RDWR, 0);
     84 	if (fd == -1)
     85 		err(EXIT_FAILURE, "open `%s'", dev);
     86 
     87 	fds.fd = fd;
     88 	fds.events = POLLOUT|POLLIN;
     89 
     90 	signal(SIGINT, handler);
     91 	for (i = 1; i <= 100; i++) {
     92 		ret = poll(&fds, 1, TIMEOUT);
     93 		if (ret == -1) {
     94 			if (errno == EINTR)
     95 				continue;
     96 			done(EXIT_FAILURE, "poll");
     97 		}
     98 		printf("Poll_executing %zu times\n", i);
     99 		if (ret == 0) {
    100 			printf("%d seconds elapsed \n.TIMEOUT.\n",
    101 			    TIMEOUT / 1000);
    102 			done(EXIT_SUCCESS, NULL);
    103 		}
    104 
    105 		if (fds.revents & (POLLERR | POLLHUP | POLLNVAL))
    106 			done(EXIT_FAILURE, "ERR|HUP|NVAL");
    107 
    108 		if (fds.revents & POLLOUT) {
    109 			do {
    110 				ret = write(fd, wbuf, sizeof(wbuf) - 1);
    111 			} while (ret == -1 && errno == EINTR);
    112 
    113 			if (ret == -1) {
    114 				done(EXIT_FAILURE, "write");
    115 			}
    116 			printf("Wrote %zd byte\n", ret);
    117 		}
    118 		if (fds.revents & POLLIN) {
    119 			memset(rbuf, 0, BUFFLEN);
    120 			do {
    121 				ret = read(fd, rbuf, BUFFLEN);
    122 			} while (ret == -1 && errno == EINTR);
    123 			if (ret == -1) {
    124 				done(EXIT_FAILURE, "read");
    125 			}
    126 			printf("Read %zd bytes\n", ret);
    127 		}
    128 	}
    129 	done(EXIT_SUCCESS, NULL);
    130 }
    131