xref: /freebsd/bin/sleep/sleep.c (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
1 /*-
2  * Copyright (c) 1988, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if 0
31 #ifndef lint
32 static char const copyright[] =
33 "@(#) Copyright (c) 1988, 1993, 1994\n\
34 	The Regents of the University of California.  All rights reserved.\n";
35 #endif /* not lint */
36 
37 #ifndef lint
38 static char sccsid[] = "@(#)sleep.c	8.3 (Berkeley) 4/2/94";
39 #endif /* not lint */
40 #endif
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 #include <capsicum_helpers.h>
45 #include <ctype.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <limits.h>
49 #include <signal.h>
50 #include <stdint.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <time.h>
54 
55 static void usage(void);
56 
57 static volatile sig_atomic_t report_requested;
58 static void
59 report_request(int signo __unused)
60 {
61 
62 	report_requested = 1;
63 }
64 
65 int
66 main(int argc, char *argv[])
67 {
68 	struct timespec time_to_sleep;
69 	double d;
70 	time_t original;
71 	char buf[2];
72 
73 	if (caph_limit_stdio() < 0 || (cap_enter() < 0 && errno != ENOSYS))
74 		err(1, "capsicum");
75 
76 	if (argc != 2)
77 		usage();
78 
79 	if (sscanf(argv[1], "%lf%1s", &d, buf) != 1)
80 		usage();
81 	if (d > INT_MAX)
82 		usage();
83 	if (d <= 0)
84 		return (0);
85 	original = time_to_sleep.tv_sec = (time_t)d;
86 	time_to_sleep.tv_nsec = 1e9 * (d - time_to_sleep.tv_sec);
87 
88 	signal(SIGINFO, report_request);
89 
90 	/*
91 	 * Note: [EINTR] is supposed to happen only when a signal was handled
92 	 * but the kernel also returns it when a ptrace-based debugger
93 	 * attaches. This is a bug but it is hard to fix.
94 	 */
95 	while (nanosleep(&time_to_sleep, &time_to_sleep) != 0) {
96 		if (report_requested) {
97 			/* Reporting does not bother with nanoseconds. */
98 			warnx("about %d second(s) left out of the original %d",
99 			    (int)time_to_sleep.tv_sec, (int)original);
100 			report_requested = 0;
101 		} else if (errno != EINTR)
102 			err(1, "nanosleep");
103 	}
104 	return (0);
105 }
106 
107 static void
108 usage(void)
109 {
110 
111 	fprintf(stderr, "usage: sleep seconds\n");
112 	exit(1);
113 }
114