xref: /freebsd/usr.bin/nice/nice.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993, 1994
5  *	The Regents of the University of California.  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  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/types.h>
33 #include <sys/time.h>
34 #include <sys/resource.h>
35 
36 #include <ctype.h>
37 #include <err.h>
38 #include <errno.h>
39 #include <limits.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <unistd.h>
43 #include <string.h>
44 
45 #define	DEFNICE	10
46 
47 void usage(void);
48 
49 int
50 main(int argc, char *argv[])
51 {
52 	long niceness = DEFNICE;
53 	int ch;
54 	char *ep;
55 
56 	/* Obsolescent syntax: -number, --number */
57 	if (argc >= 2 && argv[1][0] == '-' && (argv[1][1] == '-' ||
58 	    isdigit((unsigned char)argv[1][1])) && strcmp(argv[1], "--") != 0)
59 		if (asprintf(&argv[1], "-n%s", argv[1] + 1) < 0)
60 			err(1, "asprintf");
61 
62 	while ((ch = getopt(argc, argv, "n:")) != -1) {
63 		switch (ch) {
64 		case 'n':
65 			errno = 0;
66 			niceness = strtol(optarg, &ep, 10);
67 			if (ep == optarg || *ep != '\0' || errno ||
68 			    niceness < INT_MIN || niceness > INT_MAX)
69 				errx(1, "%s: invalid nice value", optarg);
70 			break;
71 		default:
72 			usage();
73 		}
74 	}
75 	argc -= optind;
76 	argv += optind;
77 
78 	if (argc == 0)
79 		usage();
80 
81 	errno = 0;
82 	niceness += getpriority(PRIO_PROCESS, 0);
83 	if (errno)
84 		warn("getpriority");
85 	else if (setpriority(PRIO_PROCESS, 0, (int)niceness))
86 		warn("setpriority");
87 	execvp(*argv, argv);
88 	err(errno == ENOENT ? 127 : 126, "%s", *argv);
89 }
90 
91 void
92 usage(void)
93 {
94 
95 	(void)fprintf(stderr,
96 	    "usage: nice [-n increment] utility [argument ...]\n");
97 	exit(1);
98 }
99