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