source: MondoRescue/branches/3.2/mindi-busybox/coreutils/nice.c@ 3828

/* vi: set sw=4 ts=4: */
/*
 * nice implementation for busybox
 *
 * Copyright (C) 2005  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

//usage:#define nice_trivial_usage
//usage:       "[-n ADJUST] [PROG ARGS]"
//usage:#define nice_full_usage "\n\n"
//usage:       "Change scheduling priority, run PROG\n"
//usage:     "\n    -n ADJUST   Adjust priority by ADJUST"

#include <sys/resource.h>
#include "libbb.h"

int nice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nice_main(int argc, char **argv)
{
    int old_priority, adjustment;

    old_priority = getpriority(PRIO_PROCESS, 0);

    if (!*++argv) { /* No args, so (GNU) output current nice value. */
        printf("%d\n", old_priority);
        fflush_stdout_and_exit(EXIT_SUCCESS);
    }

    adjustment = 10;  /* Set default adjustment. */

    if (argv[0][0] == '-') {
        if (argv[0][1] == 'n') { /* -n */
            if (argv[0][2]) { /* -nNNNN (w/o space) */
                argv[0] += 2; argv--; argc++;
            }
        } else { /* -NNN (NNN may be negative) == -n NNN */
            argv[0] += 1; argv--; argc++;
        }
        if (argc < 4) {  /* Missing priority and/or utility! */
            bb_show_usage();
        }
        adjustment = xatoi_range(argv[1], INT_MIN/2, INT_MAX/2);
        argv += 2;
    }

    {  /* Set our priority. */
        int prio = old_priority + adjustment;

        if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
            bb_perror_msg_and_die("setpriority(%d)", prio);
        }
    }

    BB_EXECVP_or_die(argv);
}