src/nice.c

   1 /* nice -- run a program with modified scheduling priority
   2    Copyright (C) 90, 91, 92, 93, 94, 1995 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 #include <config.h>
  21 #include <stdio.h>
  22
  23 #define NDEBUG
  24 #include <assert.h>
  25
  26 #include <getopt.h>
  27 #include <sys/types.h>
  28 #ifndef NICE_PRIORITY
  29 #include <sys/time.h>
  30 #include <sys/resource.h>
  31 #endif
  32
  33 #include "version.h"
  34 #include "system.h"
  35 #include "long-options.h"
  36 #include "error.h"
  37
  38 #ifdef NICE_PRIORITY
  39 #define GET_PRIORITY() nice (0)
  40 #else
  41 #define GET_PRIORITY() getpriority (PRIO_PROCESS, 0)
  42 #endif
  43
  44 static int isinteger ();
  45 static void usage ();
  46
  47 /* The name this program was run with. */
  48 char *program_name;
  49
  50 static struct option const longopts[] =
  51 {
  52   {"adjustment", required_argument, NULL, 'n'},
  53   {NULL, 0, NULL, 0}
  54 };
  55
  56 void
  57 main (argc, argv)
  58      int argc;
  59      char **argv;
  60 {
  61   int current_priority;
  62   int adjustment = 0;
  63   int minusflag = 0;
  64   int adjustment_given = 0;
  65   int long_option_priority = 0;
  66   int last_optind = 0;
  67
  68   program_name = argv[0];
  69   parse_long_options (argc, argv, "nice", version_string, usage);
  70
  71   for (optind = 1; optind < argc; /* empty */)
  72     {
  73       char *s;
  74
  75       s = argv[optind];
  76
  77       if (s[0] == '-' && s[1] == '-' && ISDIGIT (s[2]))
  78         {
  79           if (!isinteger (&s[2]))
  80             error (1, 0, "invalid option `%s'", s);
  81
  82           minusflag = 1;
  83           adjustment = atoi (&s[2]);
  84           adjustment_given = 1;
  85           long_option_priority = 1;
  86           ++optind;
  87         }
  88       else
  89         {
  90           int optc;
  91           while ((optc = getopt_long (argc, argv, "+0123456789n:", longopts,
  92                                       (int *) 0)) != EOF)
  93             {
  94               switch (optc)
  95                 {
  96                 case '?':
  97                   usage (1);
  98
  99                 case 'n':
 100                   if (!isinteger (optarg))
 101                     error (1, 0, "invalid priority `%s'", optarg);
 102                   adjustment = atoi (optarg);
 103                   adjustment_given = 1;
 104                   break;
 105
 106                 default:
 107                   assert (ISDIGIT (optc));
 108                   /* Reset ADJUSTMENT if the last priority-specifying option
 109                      was not of the same type or if it was, but a separate
 110                      option.  */
 111                   if (long_option_priority ||
 112                       (adjustment_given && optind != last_optind))
 113                     {
 114                       long_option_priority = 0;
 115                       adjustment = 0;
 116                     }
 117                   adjustment = adjustment * 10 + optc - '0';
 118                   adjustment_given = 1;
 119                   last_optind = optind;
 120                 }
 121             }
 122           if (optc == EOF)
 123             break;
 124         }
 125     }
 126
 127   if (minusflag)
 128     adjustment = -adjustment;
 129   if (!adjustment_given)
 130     adjustment = 10;
 131
 132   if (optind == argc)
 133     {
 134       if (adjustment_given)
 135         {
 136           error (0, 0, "a command must be given with an adjustment");
 137           usage (1);
 138         }
 139       /* No command given; print the priority. */
 140       errno = 0;
 141       current_priority = GET_PRIORITY ();
 142       if (current_priority == -1 && errno != 0)
 143         error (1, errno, "cannot get priority");
 144       printf ("%d\n", current_priority);
 145       exit (0);
 146     }
 147
 148 #ifndef NICE_PRIORITY
 149   errno = 0;
 150   current_priority = GET_PRIORITY ();
 151   if (current_priority == -1 && errno != 0)
 152     error (1, errno, "cannot get priority");
 153   if (setpriority (PRIO_PROCESS, 0, current_priority + adjustment))
 154 #else
 155   if (nice (adjustment) == -1)
 156 #endif
 157     error (1, errno, "cannot set priority");
 158
 159   execvp (argv[optind], &argv[optind]);
 160   error (errno == ENOENT ? 127 : 126, errno, "%s", argv[optind]);
 161 }
 162
 163 /* Return nonzero if S represents a (possibly signed) decimal integer,
 164    zero if not. */
 165
 166 static int
 167 isinteger (s)
 168      char *s;
 169 {
 170   if (*s == '-' || *s == '+')
 171     ++s;
 172   if (*s == 0)
 173     return 0;
 174   while (*s)
 175     {
 176       if (!ISDIGIT (*s))
 177         return 0;
 178       ++s;
 179     }
 180   return 1;
 181 }
 182
 183 static void
 184 usage (status)
 185      int status;
 186 {
 187   if (status != 0)
 188     fprintf (stderr, "Try `%s --help' for more information.\n",
 189              program_name);
 190   else
 191     {
 192       printf ("Usage: %s [OPTION]... [COMMAND [ARG]...]\n", program_name);
 193       printf ("\
 194 Run COMMAND with an adjusted scheduling priority.\n\
 195 With no COMMAND, print the current scheduling priority.  ADJUST is 10\n\
 196 by default.  Range goes from -20 (highest priority) to 19 (lowest).\n\
 197 \n\
 198   -ADJUST                   increment priority by ADJUST first\n\
 199   -n, --adjustment=ADJUST   same as -ADJUST\n\
 200       --help                display this help and exit\n\
 201       --version             output version information and exit\n");
 202     }
 203   exit (status);
 204 }