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
  23 #include <assert.h>
  24
  25 #include <getopt.h>
  26 #include <sys/types.h>
  27
  28 #include "system.h"
  29
  30 #if ! HAVE_NICE
  31 /* Include this after "system.h" so we're sure to have definitions
  32    (from time.h or sys/time.h) required for e.g. the ru_utime member.  */
  33 # include <sys/resource.h>
  34 #endif
  35
  36 #include "error.h"
  37 #include "long-options.h"
  38 #include "quote.h"
  39 #include "xstrtol.h"
  40
  41 /* The official name of this program (e.g., no `g' prefix).  */
  42 #define PROGRAM_NAME "nice"
  43
  44 #define AUTHORS "David MacKenzie"
  45
  46 #if HAVE_NICE
  47 # define GET_NICENESS() nice (0)
  48 #else
  49 # define GET_NICENESS() getpriority (PRIO_PROCESS, 0)
  50 #endif
  51
  52 #ifndef NZERO
  53 # define NZERO 20
  54 #endif
  55
  56 /* This is required for Darwin Kernel Version 7.7.0.  */
  57 #if NZERO == 0
  58 # undef  NZERO
  59 # define NZERO 20
  60 #endif
  61
  62 /* The name this program was run with. */
  63 char *program_name;
  64
  65 static struct option const longopts[] =
  66 {
  67   {"adjustment", required_argument, NULL, 'n'},
  68   {NULL, 0, NULL, 0}
  69 };
  70
  71 void
  72 usage (int status)
  73 {
  74   if (status != EXIT_SUCCESS)
  75     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  76              program_name);
  77   else
  78     {
  79       printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name);
  80       printf (_("\
  81 Run COMMAND with an adjusted niceness, which affects process scheduling.\n\
  82 With no COMMAND, print the current niceness.  Nicenesses range from\n\
  83 %d (most favorable scheduling) to %d (least favorable).\n\
  84 \n\
  85   -n, --adjustment=N   add integer N to the niceness (default 10)\n\
  86 "),
  87               - NZERO, NZERO - 1);
  88       fputs (HELP_OPTION_DESCRIPTION, stdout);
  89       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  90       printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
  91       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  92     }
  93   exit (status);
  94 }
  95
  96 int
  97 main (int argc, char **argv)
  98 {
  99   int current_niceness;
 100   int adjustment = 10;
 101   char const *adjustment_given = NULL;
 102   bool ok;
 103   int i;
 104
 105   initialize_main (&argc, &argv);
 106   program_name = argv[0];
 107   setlocale (LC_ALL, "");
 108   bindtextdomain (PACKAGE, LOCALEDIR);
 109   textdomain (PACKAGE);
 110
 111   initialize_exit_failure (EXIT_FAIL);
 112   atexit (close_stdout);
 113
 114   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
 115                       usage, AUTHORS, (char const *) NULL);
 116
 117   for (i = 1; i < argc; /* empty */)
 118     {
 119       char const *s = argv[i];
 120
 121       if (s[0] == '-' && ISDIGIT (s[1 + (s[1] == '-' || s[1] == '+')]))
 122         {
 123           adjustment_given = s + 1;
 124           ++i;
 125         }
 126       else
 127         {
 128           int optc;
 129           int fake_argc = argc - (i - 1);
 130           char **fake_argv = argv + (i - 1);
 131
 132           /* Ensure that any getopt diagnostics use the right name.  */
 133           fake_argv[0] = program_name;
 134
 135           /* Initialize getopt_long's internal state.  */
 136           optind = 0;
 137
 138           optc = getopt_long (fake_argc, fake_argv, "+n:", longopts, NULL);
 139           i += optind - 1;
 140
 141           if (optc == '?')
 142             usage (EXIT_FAIL);
 143           else if (optc == 'n')
 144             adjustment_given = optarg;
 145           else /* optc == -1 */
 146             break;
 147         }
 148     }
 149
 150   if (adjustment_given)
 151     {
 152       /* If the requested adjustment is outside the valid range,
 153          silently bring it to just within range; this mimics what
 154          "setpriority" and "nice" do.  */
 155       enum { MIN_ADJUSTMENT = 1 - 2 * NZERO, MAX_ADJUSTMENT = 2 * NZERO - 1 };
 156       long int tmp;
 157       if (LONGINT_OVERFLOW < xstrtol (adjustment_given, NULL, 10, &tmp, ""))
 158         error (EXIT_FAIL, 0, _("invalid adjustment %s"),
 159                quote (adjustment_given));
 160       adjustment = MAX (MIN_ADJUSTMENT, MIN (tmp, MAX_ADJUSTMENT));
 161     }
 162
 163   if (i == argc)
 164     {
 165       if (adjustment_given)
 166         {
 167           error (0, 0, _("a command must be given with an adjustment"));
 168           usage (EXIT_FAIL);
 169         }
 170       /* No command given; print the niceness.  */
 171       errno = 0;
 172       current_niceness = GET_NICENESS ();
 173       if (current_niceness == -1 && errno != 0)
 174         error (EXIT_FAIL, errno, _("cannot get niceness"));
 175       printf ("%d\n", current_niceness);
 176       exit (EXIT_SUCCESS);
 177     }
 178
 179   errno = 0;
 180 #if HAVE_NICE
 181   ok = (nice (adjustment) != -1 || errno == 0);
 182 #else
 183   current_niceness = GET_NICENESS ();
 184   if (current_niceness == -1 && errno != 0)
 185     error (EXIT_FAIL, errno, _("cannot get niceness"));
 186   ok = (setpriority (PRIO_PROCESS, 0, current_niceness + adjustment) == 0);
 187 #endif
 188   if (!ok)
 189     error (errno == EPERM ? 0 : EXIT_FAIL, errno, _("cannot set niceness"));
 190
 191   execvp (argv[i], &argv[i]);
 192
 193   {
 194     int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
 195     error (0, errno, "%s", argv[i]);
 196     exit (exit_status);
 197   }
 198 }