nice.c

/* nice -- run a program with modified scheduling priority
   Copyright (C) 1990-2002 Free Software Foundation, Inc.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
/* David MacKenzie <[email protected]> */
 
#include <config.h>
#include <stdio.h>
 
#include <assert.h>
 
#include <getopt.h>
#include <sys/types.h>
#ifndef NICE_PRIORITY
# include <sys/time.h>
# include <sys/resource.h>
#endif
 
#include "system.h"
#include "closeout.h"
#include "error.h"
#include "long-options.h"
#include "posixver.h"
#include "xstrtol.h"
 
/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "nice"
 
#define AUTHORS "David MacKenzie"
 
#ifdef NICE_PRIORITY
# define GET_PRIORITY() nice (0)
#else
# define GET_PRIORITY() getpriority (PRIO_PROCESS, 0)
#endif
 
/* The name this program was run with. */
char *program_name;
 
static struct option const longopts[] =
{
  {"adjustment", required_argument, NULL, 'n'},
  {NULL, 0, NULL, 0}
};
 
void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
         program_name);
  else
    {
      printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name);
      fputs (_("\
Run COMMAND with an adjusted scheduling priority.\n\
With no COMMAND, print the current scheduling priority.  ADJUST is 10\n\
by default.  Range goes from -20 (highest priority) to 19 (lowest).\n\
\n\
  -n, --adjustment=ADJUST   increment priority by ADJUST first\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    }
  exit (status);
}
 
int
main (int argc, char **argv)
{
  int current_priority;
  long int adjustment = 0;
  int minusflag = 0;
  int adjustment_given = 0;
  int i;
 
  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);
 
  atexit (close_stdout);
 
  parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
              AUTHORS, usage);
 
  for (i = 1; i < argc; /* empty */)
    {
      char *s = argv[i];
 
      if (s[0] == '-' && s[1] == '-' && ISDIGIT (s[2])
      && (posix2_version () < 200112 || !getenv ("POSIXLY_CORRECT")))
    {
      if (xstrtol (&s[2], NULL, 10, &adjustment, "") != LONGINT_OK)
        error (EXIT_FAILURE, 0, _("invalid option `%s'"), s);
 
      minusflag = 1;
      adjustment_given = 1;
      ++i;
    }
      else if (s[0] == '-'
           && (ISDIGIT (s[1]) || (s[1] == '+' && ISDIGIT (s[2])))
           && (posix2_version () < 200112 || !getenv ("POSIXLY_CORRECT")))
    {
      if (s[1] == '+')
        ++s;
      if (xstrtol (&s[1], NULL, 10, &adjustment, "") != LONGINT_OK)
        error (EXIT_FAILURE, 0, _("invalid option `%s'"), s);
 
      minusflag = 0;
      adjustment_given = 1;
      ++i;
    }
      else
    {
      int optc;
      char **fake_argv = argv + i - 1;
 
      /* Initialize getopt_long's internal state.  */
      optind = 0;
 
      if ((optc = getopt_long (argc - (i - 1), fake_argv, "+n:",
                   longopts, NULL)) != -1)
        {
          switch (optc)
        {
        case '?':
          usage (EXIT_FAILURE);
 
        case 'n':
          if (xstrtol (optarg, NULL, 10, &adjustment, "")
              != LONGINT_OK)
            error (EXIT_FAILURE, 0, _("invalid priority `%s'"), optarg);
 
          minusflag = 0;
          adjustment_given = 1;
          break;
        }
        }
 
      i += optind - 1;
 
      if (optc == EOF)
        break;
    }
    }
 
  if (minusflag)
    adjustment = -adjustment;
  if (!adjustment_given)
    adjustment = 10;
 
  if (i == argc)
    {
      if (adjustment_given)
    {
      error (0, 0, _("a command must be given with an adjustment"));
      usage (EXIT_FAILURE);
    }
      /* No command given; print the priority. */
      errno = 0;
      current_priority = GET_PRIORITY ();
      if (current_priority == -1 && errno != 0)
    error (EXIT_FAILURE, errno, _("cannot get priority"));
      printf ("%d\n", current_priority);
      exit (EXIT_SUCCESS);
    }
 
#ifndef NICE_PRIORITY
  errno = 0;
  current_priority = GET_PRIORITY ();
  if (current_priority == -1 && errno != 0)
    error (EXIT_FAILURE, errno, _("cannot get priority"));
  if (setpriority (PRIO_PROCESS, 0, current_priority + adjustment))
#else
  if (nice (adjustment) == -1)
#endif
    error (EXIT_FAILURE, errno, _("cannot set priority"));
 
  execvp (argv[i], &argv[i]);
 
  {
    int exit_status = (errno == ENOENT ? 127 : 126);
    error (0, errno, "%s", argv[i]);
    exit (exit_status);
  }
}