blob: 64213c68052da96c92da37eede12cc6d1c737302
| 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * renice implementation for busybox |
| 4 | * |
| 5 | * Copyright (C) 2005 Manuel Novoa III <mjn3@codepoet.org> |
| 6 | * |
| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| 8 | */ |
| 9 | |
| 10 | /* Notes: |
| 11 | * Setting an absolute priority was obsoleted in SUSv2 and removed |
| 12 | * in SUSv3. However, the common linux version of renice does |
| 13 | * absolute and not relative. So we'll continue supporting absolute, |
| 14 | * although the stdout logging has been removed since both SUSv2 and |
| 15 | * SUSv3 specify that stdout isn't used. |
| 16 | * |
| 17 | * This version is lenient in that it doesn't require any IDs. The |
| 18 | * options -p, -g, and -u are treated as mode switches for the |
| 19 | * following IDs (if any). Multiple switches are allowed. |
| 20 | */ |
| 21 | //config:config RENICE |
| 22 | //config: bool "renice" |
| 23 | //config: default y |
| 24 | //config: help |
| 25 | //config: Renice alters the scheduling priority of one or more running |
| 26 | //config: processes. |
| 27 | |
| 28 | //applet:IF_RENICE(APPLET(renice, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| 29 | |
| 30 | //kbuild:lib-$(CONFIG_RENICE) += renice.o |
| 31 | |
| 32 | //usage:#define renice_trivial_usage |
| 33 | //usage: "[-n] PRIORITY [[-p | -g | -u] ID...]..." |
| 34 | //usage:#define renice_full_usage "\n\n" |
| 35 | //usage: "Change scheduling priority of a running process\n" |
| 36 | //usage: "\n -n Add PRIORITY to current nice value" |
| 37 | //usage: "\n Without -n, nice value is set to PRIORITY" |
| 38 | //usage: "\n -p Process ids (default)" |
| 39 | //usage: "\n -g Process group ids" |
| 40 | //usage: "\n -u Process user names" |
| 41 | |
| 42 | #include "libbb.h" |
| 43 | #include <sys/resource.h> |
| 44 | |
| 45 | void BUG_bad_PRIO_PROCESS(void); |
| 46 | void BUG_bad_PRIO_PGRP(void); |
| 47 | void BUG_bad_PRIO_USER(void); |
| 48 | |
| 49 | int renice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 50 | int renice_main(int argc UNUSED_PARAM, char **argv) |
| 51 | { |
| 52 | static const char Xetpriority_msg[] ALIGN1 = "%cetpriority"; |
| 53 | |
| 54 | int retval = EXIT_SUCCESS; |
| 55 | int which = PRIO_PROCESS; /* Default 'which' value. */ |
| 56 | int use_relative = 0; |
| 57 | int adjustment, new_priority; |
| 58 | unsigned who; |
| 59 | char *arg; |
| 60 | |
| 61 | /* Yes, they are not #defines in glibc 2.4! #if won't work */ |
| 62 | if (PRIO_PROCESS < CHAR_MIN || PRIO_PROCESS > CHAR_MAX) |
| 63 | BUG_bad_PRIO_PROCESS(); |
| 64 | if (PRIO_PGRP < CHAR_MIN || PRIO_PGRP > CHAR_MAX) |
| 65 | BUG_bad_PRIO_PGRP(); |
| 66 | if (PRIO_USER < CHAR_MIN || PRIO_USER > CHAR_MAX) |
| 67 | BUG_bad_PRIO_USER(); |
| 68 | |
| 69 | arg = *++argv; |
| 70 | |
| 71 | /* Check if we are using a relative adjustment. */ |
| 72 | if (arg && arg[0] == '-' && arg[1] == 'n') { |
| 73 | use_relative = 1; |
| 74 | if (!arg[2]) |
| 75 | arg = *++argv; |
| 76 | else |
| 77 | arg += 2; |
| 78 | } |
| 79 | |
| 80 | if (!arg) { /* No args? Then show usage. */ |
| 81 | bb_show_usage(); |
| 82 | } |
| 83 | |
| 84 | /* Get the priority adjustment (absolute or relative). */ |
| 85 | adjustment = xatoi_range(arg, INT_MIN/2, INT_MAX/2); |
| 86 | |
| 87 | while ((arg = *++argv) != NULL) { |
| 88 | /* Check for a mode switch. */ |
| 89 | if (arg[0] == '-' && arg[1]) { |
| 90 | static const char opts[] ALIGN1 = { |
| 91 | 'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER |
| 92 | }; |
| 93 | const char *p = strchr(opts, arg[1]); |
| 94 | if (p) { |
| 95 | which = p[4]; |
| 96 | if (!arg[2]) |
| 97 | continue; |
| 98 | arg += 2; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | /* Process an ID arg. */ |
| 103 | if (which == PRIO_USER) { |
| 104 | struct passwd *p; |
| 105 | p = getpwnam(arg); |
| 106 | if (!p) { |
| 107 | bb_error_msg("unknown user %s", arg); |
| 108 | goto HAD_ERROR; |
| 109 | } |
| 110 | who = p->pw_uid; |
| 111 | } else { |
| 112 | who = bb_strtou(arg, NULL, 10); |
| 113 | if (errno) { |
| 114 | bb_error_msg("invalid number '%s'", arg); |
| 115 | goto HAD_ERROR; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | /* Get priority to use, and set it. */ |
| 120 | if (use_relative) { |
| 121 | int old_priority; |
| 122 | |
| 123 | errno = 0; /* Needed for getpriority error detection. */ |
| 124 | old_priority = getpriority(which, who); |
| 125 | if (errno) { |
| 126 | bb_perror_msg(Xetpriority_msg, 'g'); |
| 127 | goto HAD_ERROR; |
| 128 | } |
| 129 | |
| 130 | new_priority = old_priority + adjustment; |
| 131 | } else { |
| 132 | new_priority = adjustment; |
| 133 | } |
| 134 | |
| 135 | if (setpriority(which, who, new_priority) == 0) { |
| 136 | continue; |
| 137 | } |
| 138 | |
| 139 | bb_perror_msg(Xetpriority_msg, 's'); |
| 140 | HAD_ERROR: |
| 141 | retval = EXIT_FAILURE; |
| 142 | } |
| 143 | |
| 144 | /* No need to check for errors outputing to stderr since, if it |
| 145 | * was used, the HAD_ERROR label was reached and retval was set. */ |
| 146 | |
| 147 | return retval; |
| 148 | } |
| 149 |