Index: head/bin/pwait/pwait.c
===================================================================
--- head/bin/pwait/pwait.c	(revision 357139)
+++ head/bin/pwait/pwait.c	(revision 357140)
@@ -1,195 +1,195 @@
 /*-
  * Copyright (c) 2004-2009, Jilles Tjoelker
  * 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 COPYRIGHT HOLDERS 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
  * COPYRIGHT OWNER 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>
 __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/event.h>
 #include <sys/time.h>
 #include <sys/wait.h>
 
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sysexits.h>
 #include <unistd.h>
 
 static void
 usage(void)
 {
 
 	errx(EX_USAGE, "usage: pwait [-t timeout] [-v] pid ...");
 }
 
 /*
  * pwait - wait for processes to terminate
  */
 int
 main(int argc, char *argv[])
 {
 	struct itimerval itv;
 	int kq;
 	struct kevent *e;
 	int tflag, verbose;
 	int opt, nleft, n, i, status;
 	long pid;
 	char *s, *end;
 	double timeout;
 
 	tflag = verbose = 0;
 	memset(&itv, 0, sizeof(itv));
 	while ((opt = getopt(argc, argv, "t:v")) != -1) {
 		switch (opt) {
 		case 't':
 			tflag = 1;
 			errno = 0;
 			timeout = strtod(optarg, &end);
 			if (end == optarg || errno == ERANGE ||
 			    timeout < 0)
 				errx(EX_DATAERR, "timeout value");
 			switch(*end) {
 			case 0:
 			case 's':
 				break;
 			case 'h':
 				timeout *= 60;
 				/* FALLTHROUGH */
 			case 'm':
 				timeout *= 60;
 				break;
 			default:
 				errx(EX_DATAERR, "timeout unit");
 			}
 			if (timeout > 100000000L)
 				errx(EX_DATAERR, "timeout value");
 			itv.it_value.tv_sec = (time_t)timeout;
 			timeout -= (time_t)timeout;
 			itv.it_value.tv_usec =
 			    (suseconds_t)(timeout * 1000000UL);
 			break;
 		case 'v':
 			verbose = 1;
 			break;
 		default:
 			usage();
 			/* NOTREACHED */
 		}
 	}
 
 	argc -= optind;
 	argv += optind;
 
 	if (argc == 0)
 		usage();
 
 	kq = kqueue();
 	if (kq == -1)
 		err(EX_OSERR, "kqueue");
 
 	e = malloc((argc + tflag) * sizeof(struct kevent));
 	if (e == NULL)
 		err(EX_OSERR, "malloc");
 	nleft = 0;
 	for (n = 0; n < argc; n++) {
 		s = argv[n];
 		if (!strncmp(s, "/proc/", 6)) /* Undocumented Solaris compat */
 			s += 6;
 		errno = 0;
 		pid = strtol(s, &end, 10);
 		if (pid < 0 || *end != '\0' || errno != 0) {
 			warnx("%s: bad process id", s);
 			continue;
 		}
 		for (i = 0; i < nleft; i++) {
 			if (e[i].ident == (uintptr_t)pid)
 				break;
 		}
 		if (i < nleft) {
 			/* Duplicate. */
 			continue;
 		}
 		EV_SET(e + nleft, pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
 		if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
 			warn("%ld", pid);
 		else
 			nleft++;
 	}
 
-	if (tflag) {
+	if (nleft > 0 && tflag) {
 		/*
 		 * Explicitly detect SIGALRM so that an exit status of 124
 		 * can be returned rather than 142.
 		 */
 		EV_SET(e + nleft, SIGALRM, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
 		if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
 			err(EX_OSERR, "kevent");
 		/* Ignore SIGALRM to not interrupt kevent(2). */
 		signal(SIGALRM, SIG_IGN);
 		if (setitimer(ITIMER_REAL, &itv, NULL) == -1)
 			err(EX_OSERR, "setitimer");
 	}
 	while (nleft > 0) {
 		n = kevent(kq, NULL, 0, e, nleft + tflag, NULL);
 		if (n == -1)
 			err(EX_OSERR, "kevent");
 		for (i = 0; i < n; i++) {
 			if (e[i].filter == EVFILT_SIGNAL) {
 				if (verbose)
 					printf("timeout\n");
 				exit(124);
 			}
 			if (verbose) {
 				status = e[i].data;
 				if (WIFEXITED(status))
 					printf("%ld: exited with status %d.\n",
 					    (long)e[i].ident,
 					    WEXITSTATUS(status));
 				else if (WIFSIGNALED(status))
 					printf("%ld: killed by signal %d.\n",
 					    (long)e[i].ident,
 					    WTERMSIG(status));
 				else
 					printf("%ld: terminated.\n",
 					    (long)e[i].ident);
 			}
 			--nleft;
 		}
 	}
 
 	exit(EX_OK);
 }