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[coreutils.git] / src / nice.c
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1 /* nice -- run a program with modified niceness
2 Copyright (C) 1990-2005, 2007-2009 Free Software Foundation, Inc.
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 3 of the License, or
7 (at your option) any later version.
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.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* David MacKenzie <djm@gnu.ai.mit.edu> */
19 #include <config.h>
20 #include <stdio.h>
21 #include <getopt.h>
22 #include <sys/types.h>
24 #include "system.h"
26 #if ! HAVE_NICE
27 /* Include this after "system.h" so we're sure to have definitions
28 (from time.h or sys/time.h) required for e.g. the ru_utime member. */
29 # include <sys/resource.h>
30 #endif
32 #include "error.h"
33 #include "long-options.h"
34 #include "quote.h"
35 #include "xstrtol.h"
37 /* The official name of this program (e.g., no `g' prefix). */
38 #define PROGRAM_NAME "nice"
40 #define AUTHORS proper_name ("David MacKenzie")
42 #if HAVE_NICE
43 # define GET_NICENESS() nice (0)
44 #else
45 # define GET_NICENESS() getpriority (PRIO_PROCESS, 0)
46 #endif
48 #ifndef NZERO
49 # define NZERO 20
50 #endif
52 /* This is required for Darwin Kernel Version 7.7.0. */
53 #if NZERO == 0
54 # undef NZERO
55 # define NZERO 20
56 #endif
58 static struct option const longopts[] =
60 {"adjustment", required_argument, NULL, 'n'},
61 {NULL, 0, NULL, 0}
64 void
65 usage (int status)
67 if (status != EXIT_SUCCESS)
68 fprintf (stderr, _("Try `%s --help' for more information.\n"),
69 program_name);
70 else
72 printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name);
73 printf (_("\
74 Run COMMAND with an adjusted niceness, which affects process scheduling.\n\
75 With no COMMAND, print the current niceness. Nicenesses range from\n\
76 %d (most favorable scheduling) to %d (least favorable).\n\
77 \n\
78 -n, --adjustment=N add integer N to the niceness (default 10)\n\
79 "),
80 - NZERO, NZERO - 1);
81 fputs (HELP_OPTION_DESCRIPTION, stdout);
82 fputs (VERSION_OPTION_DESCRIPTION, stdout);
83 printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
84 emit_bug_reporting_address ();
86 exit (status);
89 int
90 main (int argc, char **argv)
92 int current_niceness;
93 int adjustment = 10;
94 char const *adjustment_given = NULL;
95 bool ok;
96 int i;
98 initialize_main (&argc, &argv);
99 set_program_name (argv[0]);
100 setlocale (LC_ALL, "");
101 bindtextdomain (PACKAGE, LOCALEDIR);
102 textdomain (PACKAGE);
104 initialize_exit_failure (EXIT_FAILURE);
105 atexit (close_stdout);
107 parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
108 usage, AUTHORS, (char const *) NULL);
110 for (i = 1; i < argc; /* empty */)
112 char const *s = argv[i];
114 if (s[0] == '-' && ISDIGIT (s[1 + (s[1] == '-' || s[1] == '+')]))
116 adjustment_given = s + 1;
117 ++i;
119 else
121 int optc;
122 int fake_argc = argc - (i - 1);
123 char **fake_argv = argv + (i - 1);
125 /* Ensure that any getopt diagnostics use the right name. */
126 fake_argv[0] = argv[0];
128 /* Initialize getopt_long's internal state. */
129 optind = 0;
131 optc = getopt_long (fake_argc, fake_argv, "+n:", longopts, NULL);
132 i += optind - 1;
134 if (optc == '?')
135 usage (EXIT_FAILURE);
136 else if (optc == 'n')
137 adjustment_given = optarg;
138 else /* optc == -1 */
139 break;
143 if (adjustment_given)
145 /* If the requested adjustment is outside the valid range,
146 silently bring it to just within range; this mimics what
147 "setpriority" and "nice" do. */
148 enum { MIN_ADJUSTMENT = 1 - 2 * NZERO, MAX_ADJUSTMENT = 2 * NZERO - 1 };
149 long int tmp;
150 if (LONGINT_OVERFLOW < xstrtol (adjustment_given, NULL, 10, &tmp, ""))
151 error (EXIT_FAILURE, 0, _("invalid adjustment %s"),
152 quote (adjustment_given));
153 adjustment = MAX (MIN_ADJUSTMENT, MIN (tmp, MAX_ADJUSTMENT));
156 if (i == argc)
158 if (adjustment_given)
160 error (0, 0, _("a command must be given with an adjustment"));
161 usage (EXIT_FAILURE);
163 /* No command given; print the niceness. */
164 errno = 0;
165 current_niceness = GET_NICENESS ();
166 if (current_niceness == -1 && errno != 0)
167 error (EXIT_FAILURE, errno, _("cannot get niceness"));
168 printf ("%d\n", current_niceness);
169 exit (EXIT_SUCCESS);
172 errno = 0;
173 #if HAVE_NICE
174 ok = (nice (adjustment) != -1 || errno == 0);
175 #else
176 current_niceness = GET_NICENESS ();
177 if (current_niceness == -1 && errno != 0)
178 error (EXIT_FAILURE, errno, _("cannot get niceness"));
179 ok = (setpriority (PRIO_PROCESS, 0, current_niceness + adjustment) == 0);
180 #endif
181 if (!ok)
182 error (errno == EPERM ? 0 : EXIT_FAILURE, errno, _("cannot set niceness"));
184 execvp (argv[i], &argv[i]);
187 int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
188 error (0, errno, "%s", argv[i]);
189 exit (exit_status);