| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * renice 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 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | */
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| 9 |
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| 10 | /* Notes:
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| 11 | * Setting an absolute priority was obsoleted in SUSv2 and removed
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| 12 | * in SUSv3. However, the common linux version of renice does
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| 13 | * absolute and not relative. So we'll continue supporting absolute,
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| 14 | * although the stdout logging has been removed since both SUSv2 and
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| 15 | * SUSv3 specify that stdout isn't used.
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| 16 | *
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| 17 | * This version is lenient in that it doesn't require any IDs. The
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| 18 | * options -p, -g, and -u are treated as mode switches for the
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| 19 | * following IDs (if any). Multiple switches are allowed.
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| 20 | */
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| 21 |
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| 22 | //usage:#define renice_trivial_usage
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| 23 | //usage: "[-n] PRIORITY [[-p | -g | -u] ID...]..."
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| 24 | //usage:#define renice_full_usage "\n\n"
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| 25 | //usage: "Change scheduling priority of a running process\n"
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| 26 | //usage: "\n -n Add PRIORITY to current nice value"
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| 27 | //usage: "\n Without -n, nice value is set to PRIORITY"
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| 28 | //usage: "\n -p Process ids (default)"
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| 29 | //usage: "\n -g Process group ids"
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| 30 | //usage: "\n -u Process user names"
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| 31 |
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| 32 | #include "libbb.h"
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| 33 | #include <sys/resource.h>
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| 34 |
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| 35 | void BUG_bad_PRIO_PROCESS(void);
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| 36 | void BUG_bad_PRIO_PGRP(void);
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| 37 | void BUG_bad_PRIO_USER(void);
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| 38 |
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| 39 | int renice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 40 | int renice_main(int argc UNUSED_PARAM, char **argv)
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| 41 | {
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| 42 | static const char Xetpriority_msg[] ALIGN1 = "%cetpriority";
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| 43 |
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| 44 | int retval = EXIT_SUCCESS;
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| 45 | int which = PRIO_PROCESS; /* Default 'which' value. */
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| 46 | int use_relative = 0;
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| 47 | int adjustment, new_priority;
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| 48 | unsigned who;
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| 49 | char *arg;
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| 50 |
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| 51 | /* Yes, they are not #defines in glibc 2.4! #if won't work */
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| 52 | if (PRIO_PROCESS < CHAR_MIN || PRIO_PROCESS > CHAR_MAX)
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| 53 | BUG_bad_PRIO_PROCESS();
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| 54 | if (PRIO_PGRP < CHAR_MIN || PRIO_PGRP > CHAR_MAX)
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| 55 | BUG_bad_PRIO_PGRP();
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| 56 | if (PRIO_USER < CHAR_MIN || PRIO_USER > CHAR_MAX)
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| 57 | BUG_bad_PRIO_USER();
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| 58 |
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| 59 | arg = *++argv;
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| 60 |
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| 61 | /* Check if we are using a relative adjustment. */
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| 62 | if (arg && arg[0] == '-' && arg[1] == 'n') {
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| 63 | use_relative = 1;
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| 64 | if (!arg[2])
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| 65 | arg = *++argv;
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| 66 | else
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| 67 | arg += 2;
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| 68 | }
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| 69 |
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| 70 | if (!arg) { /* No args? Then show usage. */
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| 71 | bb_show_usage();
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| 72 | }
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| 73 |
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| 74 | /* Get the priority adjustment (absolute or relative). */
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| 75 | adjustment = xatoi_range(arg, INT_MIN/2, INT_MAX/2);
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| 76 |
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| 77 | while ((arg = *++argv) != NULL) {
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| 78 | /* Check for a mode switch. */
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| 79 | if (arg[0] == '-' && arg[1]) {
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| 80 | static const char opts[] ALIGN1 = {
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| 81 | 'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER
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| 82 | };
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| 83 | const char *p = strchr(opts, arg[1]);
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| 84 | if (p) {
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| 85 | which = p[4];
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| 86 | if (!arg[2])
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| 87 | continue;
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| 88 | arg += 2;
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| 89 | }
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| 90 | }
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| 91 |
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| 92 | /* Process an ID arg. */
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| 93 | if (which == PRIO_USER) {
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| 94 | struct passwd *p;
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| 95 | p = getpwnam(arg);
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| 96 | if (!p) {
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| 97 | bb_error_msg("unknown user %s", arg);
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| 98 | goto HAD_ERROR;
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| 99 | }
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| 100 | who = p->pw_uid;
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| 101 | } else {
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| 102 | who = bb_strtou(arg, NULL, 10);
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| 103 | if (errno) {
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| 104 | bb_error_msg("invalid number '%s'", arg);
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| 105 | goto HAD_ERROR;
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| 106 | }
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| 107 | }
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| 108 |
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| 109 | /* Get priority to use, and set it. */
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| 110 | if (use_relative) {
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| 111 | int old_priority;
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| 112 |
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| 113 | errno = 0; /* Needed for getpriority error detection. */
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| 114 | old_priority = getpriority(which, who);
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| 115 | if (errno) {
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| 116 | bb_perror_msg(Xetpriority_msg, 'g');
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| 117 | goto HAD_ERROR;
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| 118 | }
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| 119 |
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| 120 | new_priority = old_priority + adjustment;
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| 121 | } else {
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| 122 | new_priority = adjustment;
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| 123 | }
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| 124 |
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| 125 | if (setpriority(which, who, new_priority) == 0) {
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| 126 | continue;
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| 127 | }
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| 128 |
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| 129 | bb_perror_msg(Xetpriority_msg, 's');
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| 130 | HAD_ERROR:
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| 131 | retval = EXIT_FAILURE;
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| 132 | }
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| 133 |
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| 134 | /* No need to check for errors outputing to stderr since, if it
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| 135 | * was used, the HAD_ERROR label was reached and retval was set. */
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| 136 |
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| 137 | return retval;
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| 138 | }
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