commands/nice/nice.c

   1 /*
   2  * Copyright (c) 1989, 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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/types.h>
  35 #include <sys/time.h>
  36 #include <sys/resource.h>
  37
  38 #include <ctype.h>
  39 #include <errno.h>
  40 #include <limits.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <unistd.h>
  44 #include <string.h>
  45
  46 #define DEFNICE 10
  47
  48 void usage(void);
  49
  50 int
  51 main(int argc, char *argv[])
  52 {
  53         long niceness = DEFNICE;
  54         int ch;
  55         char *ep;
  56         char arg1[10];
  57
  58         /* Obsolescent syntax: -number, --number */
  59         if (argc >= 2 && argv[1][0] == '-' && (argv[1][1] == '-' ||
  60             isdigit((unsigned char)argv[1][1])) && strcmp(argv[1], "--") != 0) {
  61                 snprintf(arg1, sizeof(arg1), "-n%s", argv[1] + 1);
  62                 argv[1] = arg1;
  63         }
  64
  65         while ((ch = getopt(argc, argv, "n:")) != -1) {
  66                 switch (ch) {
  67                 case 'n':
  68                         errno = 0;
  69                         niceness = strtol(optarg, &ep, 10);
  70                         if (ep == optarg || *ep != '\0' || errno ||
  71                             niceness < INT_MIN || niceness > INT_MAX) {
  72                                 fprintf(stderr, "%s: invalid nice value", optarg);
  73                                 return 1;
  74                         }
  75                         break;
  76                 default:
  77                         usage();
  78                 }
  79         }
  80         argc -= optind;
  81         argv += optind;
  82
  83         if (argc == 0)
  84                 usage();
  85
  86         errno = 0;
  87         niceness += getpriority(PRIO_PROCESS, 0);
  88         if (errno) {
  89                 perror("getpriority");
  90                 return 1;
  91         }
  92         if (setpriority(PRIO_PROCESS, 0, (int)niceness)) {
  93                 perror("setpriority");
  94                 return 1;
  95         }
  96         errno = 0;
  97         execvp(*argv, argv);
  98         perror("execvp");
  99         return 1;
 100 }
 101
 102 void
 103 usage(void)
 104 {
 105
 106         (void)fprintf(stderr, "usage: nice [-n incr] utility [arguments]\n");
 107         exit(1);
 108 }