summaryrefslogtreecommitdiff
path: root/src/nice.c
blob: b04f675fbc574865cec76db787d7552391e147d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/* nice -- run a program with modified niceness
   Copyright (C) 1990-2005, 2007-2009 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.  */

/* David MacKenzie <djm@gnu.ai.mit.edu> */

#include <config.h>
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>

#include "system.h"

#if ! HAVE_NICE
/* Include this after "system.h" so we're sure to have definitions
   (from time.h or sys/time.h) required for e.g. the ru_utime member.  */
# include <sys/resource.h>
#endif

#include "error.h"
#include "long-options.h"
#include "quote.h"
#include "xstrtol.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "nice"

#define AUTHORS proper_name ("David MacKenzie")

#if HAVE_NICE
# define GET_NICENESS() nice (0)
#else
# define GET_NICENESS() getpriority (PRIO_PROCESS, 0)
#endif

#ifndef NZERO
# define NZERO 20
#endif

/* This is required for Darwin Kernel Version 7.7.0.  */
#if NZERO == 0
# undef  NZERO
# define NZERO 20
#endif

static struct option const longopts[] =
{
  {"adjustment", required_argument, NULL, 'n'},
  {NULL, 0, NULL, 0}
};

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
             program_name);
  else
    {
      printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name);
      printf (_("\
Run COMMAND with an adjusted niceness, which affects process scheduling.\n\
With no COMMAND, print the current niceness.  Nicenesses range from\n\
%d (most favorable scheduling) to %d (least favorable).\n\
\n\
  -n, --adjustment=N   add integer N to the niceness (default 10)\n\
"),
              - NZERO, NZERO - 1);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
      emit_ancillary_info ();
    }
  exit (status);
}

int
main (int argc, char **argv)
{
  int current_niceness;
  int adjustment = 10;
  char const *adjustment_given = NULL;
  bool ok;
  int i;

  initialize_main (&argc, &argv);
  set_program_name (argv[0]);
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  initialize_exit_failure (EXIT_CANCELED);
  atexit (close_stdout);

  parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
                      usage, AUTHORS, (char const *) NULL);

  for (i = 1; i < argc; /* empty */)
    {
      char const *s = argv[i];

      if (s[0] == '-' && ISDIGIT (s[1 + (s[1] == '-' || s[1] == '+')]))
        {
          adjustment_given = s + 1;
          ++i;
        }
      else
        {
          int optc;
          int fake_argc = argc - (i - 1);
          char **fake_argv = argv + (i - 1);

          /* Ensure that any getopt diagnostics use the right name.  */
          fake_argv[0] = argv[0];

          /* Initialize getopt_long's internal state.  */
          optind = 0;

          optc = getopt_long (fake_argc, fake_argv, "+n:", longopts, NULL);
          i += optind - 1;

          if (optc == '?')
            usage (EXIT_CANCELED);
          else if (optc == 'n')
            adjustment_given = optarg;
          else /* optc == -1 */
            break;
        }
    }

  if (adjustment_given)
    {
      /* If the requested adjustment is outside the valid range,
         silently bring it to just within range; this mimics what
         "setpriority" and "nice" do.  */
      enum { MIN_ADJUSTMENT = 1 - 2 * NZERO, MAX_ADJUSTMENT = 2 * NZERO - 1 };
      long int tmp;
      if (LONGINT_OVERFLOW < xstrtol (adjustment_given, NULL, 10, &tmp, ""))
        error (EXIT_CANCELED, 0, _("invalid adjustment %s"),
               quote (adjustment_given));
      adjustment = MAX (MIN_ADJUSTMENT, MIN (tmp, MAX_ADJUSTMENT));
    }

  if (i == argc)
    {
      if (adjustment_given)
        {
          error (0, 0, _("a command must be given with an adjustment"));
          usage (EXIT_CANCELED);
        }
      /* No command given; print the niceness.  */
      errno = 0;
      current_niceness = GET_NICENESS ();
      if (current_niceness == -1 && errno != 0)
        error (EXIT_CANCELED, errno, _("cannot get niceness"));
      printf ("%d\n", current_niceness);
      exit (EXIT_SUCCESS);
    }

  errno = 0;
#if HAVE_NICE
  ok = (nice (adjustment) != -1 || errno == 0);
#else
  current_niceness = GET_NICENESS ();
  if (current_niceness == -1 && errno != 0)
    error (EXIT_CANCELED, errno, _("cannot get niceness"));
  ok = (setpriority (PRIO_PROCESS, 0, current_niceness + adjustment) == 0);
#endif
  if (!ok)
    error (errno == EPERM ? 0 : EXIT_CANCELED, errno, _("cannot set niceness"));

  execvp (argv[i], &argv[i]);

  {
    int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
    error (0, errno, "%s", argv[i]);
    exit (exit_status);
  }
}