src/nice.c

   1 /* nice -- run a program with modified niceness
   2    Copyright (C) 1990-2005 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 Foundation,
  16    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  17
  18 /* David MacKenzie <djm@gnu.ai.mit.edu> */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <getopt.h>
  23 #include <sys/types.h>
  24
  25 #include "system.h"
  26
  27 #if ! HAVE_NICE
  28 /* Include this after "system.h" so we're sure to have definitions
  29    (from time.h or sys/time.h) required for e.g. the ru_utime member.  */
  30 # include <sys/resource.h>
  31 #endif
  32
  33 #include "error.h"
  34 #include "long-options.h"
  35 #include "quote.h"
  36 #include "xstrtol.h"
  37
  38 /* The official name of this program (e.g., no `g' prefix).  */
  39 #define PROGRAM_NAME "nice"
  40
  41 #define AUTHORS "David MacKenzie"
  42
  43 #if HAVE_NICE
  44 # define GET_NICENESS() nice (0)
  45 #else
  46 # define GET_NICENESS() getpriority (PRIO_PROCESS, 0)
  47 #endif
  48
  49 #ifndef NZERO
  50 # define NZERO 20
  51 #endif
  52
  53 /* This is required for Darwin Kernel Version 7.7.0.  */
  54 #if NZERO == 0
  55 # undef  NZERO
  56 # define NZERO 20
  57 #endif
  58
  59 /* The name this program was run with. */
  60 char *program_name;
  61
  62 static struct option const longopts[] =
  63 {
  64   {"adjustment", required_argument, NULL, 'n'},
  65   {NULL, 0, NULL, 0}
  66 };
  67
  68 void
  69 usage (int status)
  70 {
  71   if (status != EXIT_SUCCESS)
  72     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  73              program_name);
  74   else
  75     {
  76       printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name);
  77       printf (_("\
  78 Run COMMAND with an adjusted niceness, which affects process scheduling.\n\
  79 With no COMMAND, print the current niceness.  Nicenesses range from\n\
  80 %d (most favorable scheduling) to %d (least favorable).\n\
  81 \n\
  82   -n, --adjustment=N   add integer N to the niceness (default 10)\n\
  83 "),
  84               - NZERO, NZERO - 1);
  85       fputs (HELP_OPTION_DESCRIPTION, stdout);
  86       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  87       printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
  88       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  89     }
  90   exit (status);
  91 }
  92
  93 int
  94 main (int argc, char **argv)
  95 {
  96   int current_niceness;
  97   int adjustment = 10;
  98   char const *adjustment_given = NULL;
  99   bool ok;
 100   int i;
 101
 102   initialize_main (&argc, &argv);
 103   program_name = argv[0];
 104   setlocale (LC_ALL, "");
 105   bindtextdomain (PACKAGE, LOCALEDIR);
 106   textdomain (PACKAGE);
 107
 108   initialize_exit_failure (EXIT_FAIL);
 109   atexit (close_stdout);
 110
 111   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
 112                       usage, AUTHORS, (char const *) NULL);
 113
 114   for (i = 1; i < argc; /* empty */)
 115     {
 116       char const *s = argv[i];
 117
 118       if (s[0] == '-' && ISDIGIT (s[1 + (s[1] == '-' || s[1] == '+')]))
 119         {
 120           adjustment_given = s + 1;
 121           ++i;
 122         }
 123       else
 124         {
 125           int optc;
 126           int fake_argc = argc - (i - 1);
 127           char **fake_argv = argv + (i - 1);
 128
 129           /* Ensure that any getopt diagnostics use the right name.  */
 130           fake_argv[0] = program_name;
 131
 132           /* Initialize getopt_long's internal state.  */
 133           optind = 0;
 134
 135           optc = getopt_long (fake_argc, fake_argv, "+n:", longopts, NULL);
 136           i += optind - 1;
 137
 138           if (optc == '?')
 139             usage (EXIT_FAIL);
 140           else if (optc == 'n')
 141             adjustment_given = optarg;
 142           else /* optc == -1 */
 143             break;
 144         }
 145     }
 146
 147   if (adjustment_given)
 148     {
 149       /* If the requested adjustment is outside the valid range,
 150          silently bring it to just within range; this mimics what
 151          "setpriority" and "nice" do.  */
 152       enum { MIN_ADJUSTMENT = 1 - 2 * NZERO, MAX_ADJUSTMENT = 2 * NZERO - 1 };
 153       long int tmp;
 154       if (LONGINT_OVERFLOW < xstrtol (adjustment_given, NULL, 10, &tmp, ""))
 155         error (EXIT_FAIL, 0, _("invalid adjustment %s"),
 156                quote (adjustment_given));
 157       adjustment = MAX (MIN_ADJUSTMENT, MIN (tmp, MAX_ADJUSTMENT));
 158     }
 159
 160   if (i == argc)
 161     {
 162       if (adjustment_given)
 163         {
 164           error (0, 0, _("a command must be given with an adjustment"));
 165           usage (EXIT_FAIL);
 166         }
 167       /* No command given; print the niceness.  */
 168       errno = 0;
 169       current_niceness = GET_NICENESS ();
 170       if (current_niceness == -1 && errno != 0)
 171         error (EXIT_FAIL, errno, _("cannot get niceness"));
 172       printf ("%d\n", current_niceness);
 173       exit (EXIT_SUCCESS);
 174     }
 175
 176   errno = 0;
 177 #if HAVE_NICE
 178   ok = (nice (adjustment) != -1 || errno == 0);
 179 #else
 180   current_niceness = GET_NICENESS ();
 181   if (current_niceness == -1 && errno != 0)
 182     error (EXIT_FAIL, errno, _("cannot get niceness"));
 183   ok = (setpriority (PRIO_PROCESS, 0, current_niceness + adjustment) == 0);
 184 #endif
 185   if (!ok)
 186     error (errno == EPERM ? 0 : EXIT_FAIL, errno, _("cannot set niceness"));
 187
 188   execvp (argv[i], &argv[i]);
 189
 190   {
 191     int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
 192     error (0, errno, "%s", argv[i]);
 193     exit (exit_status);
 194   }
 195 }