src/nice.c

   1 /* nice -- run a program with modified scheduling priority
   2    Copyright (C) 1990, 1991 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 /* David MacKenzie <djm@gnu.ai.mit.edu> */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #if defined (CONFIG_BROKETS)
  22 /* We use <config.h> instead of "config.h" so that a compilation
  23    using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
  24    (which it would do because it found this file in $srcdir).  */
  25 #include <config.h>
  26 #else
  27 #include "config.h"
  28 #endif
  29 #endif
  30
  31 #include <stdio.h>
  32 #include <getopt.h>
  33 #include <sys/types.h>
  34 #ifndef NICE_PRIORITY
  35 #include <sys/time.h>
  36 #include <sys/resource.h>
  37 #endif
  38
  39 #include "version.h"
  40 #include "system.h"
  41
  42 #ifdef NICE_PRIORITY
  43 #define GET_PRIORITY() nice (0)
  44 #else
  45 #define GET_PRIORITY() getpriority (PRIO_PROCESS, 0)
  46 #endif
  47
  48 void error ();
  49
  50 static int isinteger ();
  51 static void usage ();
  52
  53 /* The name this program was run with. */
  54 char *program_name;
  55
  56 /* If non-zero, display usage information and exit.  */
  57 static int show_help;
  58
  59 /* If non-zero, print the version on standard output and exit.  */
  60 static int show_version;
  61
  62 static struct option const longopts[] =
  63 {
  64   {"adjustment", required_argument, NULL, 'n'},
  65   {"help", no_argument, &show_help, 1},
  66   {"version", no_argument, &show_version, 1},
  67   {NULL, 0, NULL, 0}
  68 };
  69
  70 void
  71 main (argc, argv)
  72      int argc;
  73      char **argv;
  74 {
  75   int current_priority;
  76   int adjustment = 0;
  77   int minusflag = 0;
  78   int adjustment_given = 0;
  79   int optc;
  80
  81   program_name = argv[0];
  82
  83   while ((optc = getopt_long (argc, argv, "+0123456789-n:", longopts,
  84                               (int *) 0)) != EOF)
  85     {
  86       switch (optc)
  87         {
  88         case '?':
  89           usage ();
  90
  91         case 0:
  92           break;
  93
  94         case 'n':
  95           if (!isinteger (optarg))
  96             error (1, 0, "invalid priority `%s'", optarg);
  97           adjustment = atoi (optarg);
  98           adjustment_given = 1;
  99           break;
 100
 101         case '-':
 102           minusflag = 1;
 103           break;
 104
 105         default:
 106           adjustment = adjustment * 10 + optc - '0';
 107           adjustment_given = 1;
 108         }
 109     }
 110
 111   if (show_version)
 112     {
 113       printf ("%s\n", version_string);
 114       exit (0);
 115     }
 116
 117   if (show_help)
 118     usage ();
 119
 120   if (minusflag)
 121     adjustment = -adjustment;
 122   if (!adjustment_given)
 123     adjustment = 10;
 124
 125   if (optind == argc)
 126     {
 127       if (adjustment_given)
 128         usage ();
 129       /* No command given; print the priority. */
 130       errno = 0;
 131       current_priority = GET_PRIORITY ();
 132       if (current_priority == -1 && errno != 0)
 133         error (1, errno, "cannot get priority");
 134       printf ("%d\n", current_priority);
 135       exit (0);
 136     }
 137
 138 #ifndef NICE_PRIORITY
 139   errno = 0;
 140   current_priority = GET_PRIORITY ();
 141   if (current_priority == -1 && errno != 0)
 142     error (1, errno, "cannot get priority");
 143   if (setpriority (PRIO_PROCESS, 0, current_priority + adjustment))
 144 #else
 145   if (nice (adjustment) == -1)
 146 #endif
 147     error (1, errno, "cannot set priority");
 148
 149   execvp (argv[optind], &argv[optind]);
 150   error (errno == ENOENT ? 127 : 126, errno, "%s", argv[optind]);
 151 }
 152
 153 /* Return nonzero if S represents a (possibly signed) decimal integer,
 154    zero if not. */
 155
 156 static int
 157 isinteger (s)
 158      char *s;
 159 {
 160   if (*s == '-')
 161     ++s;
 162   if (*s == 0)
 163     return 0;
 164   while (*s)
 165     {
 166       if (*s < '0' || *s > '9')
 167         return 0;
 168       ++s;
 169     }
 170   return 1;
 171 }
 172
 173 static void
 174 usage ()
 175 {
 176   fprintf (stderr, "\
 177 Usage: %s [-n adjustment] [-adjustment] [--adjustment=adjustment]\n\
 178        [command [arg...]]\n",
 179            program_name);
 180   exit (1);
 181 }