/* $OpenBSD: select.c,v 1.3 2003/07/31 21:48:06 deraadt Exp $ */ /* * Copyright (c) 1993, 1994, 1995, 1996 by Chris Provenzano and contributors, * proven@mit.edu 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Chris Provenzano, * the University of California, Berkeley, and contributors. * 4. Neither the name of Chris Provenzano, the University, nor the names of * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO 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 CHRIS PROVENZANO, THE REGENTS 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. */ /* * Rudimentary test of select(). */ #include #include #include #include #include #include #include #include #include #include "test.h" #define NLOOPS 10000 int ntouts = 0; static void * bg_routine(void *arg) { char dot = '.'; int n; SET_NAME("bg"); /* Busy loop, printing dots */ for (;;) { pthread_yield(); write(STDOUT_FILENO, &dot, sizeof dot); pthread_yield(); n = NLOOPS; while (n-- > 0) pthread_yield(); } } static void * fg_routine(void *arg) { int flags; int n; fd_set r; int fd = fileno((FILE *) arg); int tty = isatty(fd); int maxfd; int nb; char buf[128]; SET_NAME("fg"); /* Set the file descriptor to non-blocking */ flags = fcntl(fd, F_GETFL); CHECKr(fcntl(fd, F_SETFL, flags | O_NONBLOCK)); for (;;) { /* Print a prompt if it's a tty: */ if (tty) { printf("type something> "); fflush(stdout); } /* Select on the fdesc: */ FD_ZERO(&r); FD_SET(fd, &r); maxfd = fd; errno = 0; CHECKe(n = select(maxfd + 1, &r, (fd_set *) 0, (fd_set *) 0, (struct timeval *) 0)); if (n > 0) { /* Something was ready for read. */ printf("select returned %d\n", n); while ((nb = read(fd, buf, sizeof(buf) - 1)) > 0) { printf("read %d: `%.*s'\n", nb, nb, buf); } printf("last read was %d, errno = %d %s\n", nb, errno, errno == 0 ? "success" : strerror(errno)); if (nb < 0) ASSERTe(errno, == EWOULDBLOCK || errno == EAGAIN); if (nb == 0) break; } else ntouts++; } printf("read finished\n"); return (NULL); } int main(int argc, char *argv[]) { pthread_t bg_thread, fg_thread; FILE * slpr; /* Create a fdesc that will block for a while on read: */ CHECKn(slpr = popen("sleep 2; echo foo", "r")); /* Create a busy loop thread that yields a lot: */ CHECKr(pthread_create(&bg_thread, NULL, bg_routine, 0)); /* Create the thread that reads the fdesc: */ CHECKr(pthread_create(&fg_thread, NULL, fg_routine, (void *) slpr)); /* Wait for the reader thread to finish */ CHECKr(pthread_join(fg_thread, NULL)); /* Clean up*/ CHECKe(pclose(slpr)); SUCCEED; }