source: branches/stable/mindi-busybox/coreutils/nice.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 2.3 KB
RevLine 
[821]1/* vi: set sw=4 ts=4: */
2/*
3 * nice implementation for busybox
4 *
5 * Copyright (C) 2005  Manuel Novoa III  <mjn3@codepoet.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 */
22
23#include <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26#include <limits.h>
27#include <errno.h>
28#include <unistd.h>
29#include <sys/resource.h>
30#include "busybox.h"
31
32static inline int int_add_no_wrap(int a, int b)
33{
34    int s = a + b;
35
36    if (b < 0) {
37        if (s > a) s = INT_MIN;
38    } else {
39        if (s < a) s = INT_MAX;
40    }
41
42    return s;
43}
44
45int nice_main(int argc, char **argv)
46{
47    static const char Xetpriority_msg[] = "cannot %cet priority";
48
49    int old_priority, adjustment;
50
51    errno = 0;           /* Needed for getpriority error detection. */
52    old_priority = getpriority(PRIO_PROCESS, 0);
53    if (errno) {
54        bb_perror_msg_and_die(Xetpriority_msg, 'g');
55    }
56
57    if (!*++argv) { /* No args, so (GNU) output current nice value. */
58        bb_printf("%d\n", old_priority);
59        bb_fflush_stdout_and_exit(EXIT_SUCCESS);
60    }
61
62    adjustment = 10;            /* Set default adjustment. */
63
64    if ((argv[0][0] == '-') && (argv[0][1] == 'n') && !argv[0][2]) { /* "-n" */
65        if (argc < 4) {         /* Missing priority and/or utility! */
66            bb_show_usage();
67        }
68        adjustment = bb_xgetlarg(argv[1], 10, INT_MIN, INT_MAX);
69        argv += 2;
70    }
71
72    {  /* Set our priority.  Handle integer wrapping for old + adjust. */
73        int new_priority = int_add_no_wrap(old_priority, adjustment);
74
75        if (setpriority(PRIO_PROCESS, 0, new_priority) < 0) {
76            bb_perror_msg_and_die(Xetpriority_msg, 's');
77        }
78    }
79
80    execvp(*argv, argv);        /* Now exec the desired program. */
81
82    /* The exec failed... */
83    bb_default_error_retval = (errno == ENOENT) ? 127 : 126; /* SUSv3 */
84    bb_perror_msg_and_die("%s", *argv);
85}
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