blob: 77f400a1d643bbfd174005bda1a9246cf7ed0f02
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 | |
22 | //usage:#define renice_trivial_usage |
23 | //usage: "{{-n INCREMENT} | PRIORITY} [[-p | -g | -u] ID...]" |
24 | //usage:#define renice_full_usage "\n\n" |
25 | //usage: "Change scheduling priority for a running process\n" |
26 | //usage: "\n -n Adjust current nice value (smaller is faster)" |
27 | //usage: "\n -p Process id(s) (default)" |
28 | //usage: "\n -g Process group id(s)" |
29 | //usage: "\n -u Process user name(s) and/or id(s)" |
30 | |
31 | #include "libbb.h" |
32 | #include <sys/resource.h> |
33 | |
34 | void BUG_bad_PRIO_PROCESS(void); |
35 | void BUG_bad_PRIO_PGRP(void); |
36 | void BUG_bad_PRIO_USER(void); |
37 | |
38 | int renice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
39 | int renice_main(int argc UNUSED_PARAM, char **argv) |
40 | { |
41 | static const char Xetpriority_msg[] ALIGN1 = "%cetpriority"; |
42 | |
43 | int retval = EXIT_SUCCESS; |
44 | int which = PRIO_PROCESS; /* Default 'which' value. */ |
45 | int use_relative = 0; |
46 | int adjustment, new_priority; |
47 | unsigned who; |
48 | char *arg; |
49 | |
50 | /* Yes, they are not #defines in glibc 2.4! #if won't work */ |
51 | if (PRIO_PROCESS < CHAR_MIN || PRIO_PROCESS > CHAR_MAX) |
52 | BUG_bad_PRIO_PROCESS(); |
53 | if (PRIO_PGRP < CHAR_MIN || PRIO_PGRP > CHAR_MAX) |
54 | BUG_bad_PRIO_PGRP(); |
55 | if (PRIO_USER < CHAR_MIN || PRIO_USER > CHAR_MAX) |
56 | BUG_bad_PRIO_USER(); |
57 | |
58 | arg = *++argv; |
59 | |
60 | /* Check if we are using a relative adjustment. */ |
61 | if (arg && arg[0] == '-' && arg[1] == 'n') { |
62 | use_relative = 1; |
63 | if (!arg[2]) |
64 | arg = *++argv; |
65 | else |
66 | arg += 2; |
67 | } |
68 | |
69 | if (!arg) { /* No args? Then show usage. */ |
70 | bb_show_usage(); |
71 | } |
72 | |
73 | /* Get the priority adjustment (absolute or relative). */ |
74 | adjustment = xatoi_range(arg, INT_MIN/2, INT_MAX/2); |
75 | |
76 | while ((arg = *++argv) != NULL) { |
77 | /* Check for a mode switch. */ |
78 | if (arg[0] == '-' && arg[1]) { |
79 | static const char opts[] ALIGN1 = { |
80 | 'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER |
81 | }; |
82 | const char *p = strchr(opts, arg[1]); |
83 | if (p) { |
84 | which = p[4]; |
85 | if (!arg[2]) |
86 | continue; |
87 | arg += 2; |
88 | } |
89 | } |
90 | |
91 | /* Process an ID arg. */ |
92 | if (which == PRIO_USER) { |
93 | struct passwd *p; |
94 | p = getpwnam(arg); |
95 | if (!p) { |
96 | bb_error_msg("unknown user %s", arg); |
97 | goto HAD_ERROR; |
98 | } |
99 | who = p->pw_uid; |
100 | } else { |
101 | who = bb_strtou(arg, NULL, 10); |
102 | if (errno) { |
103 | bb_error_msg("invalid number '%s'", arg); |
104 | goto HAD_ERROR; |
105 | } |
106 | } |
107 | |
108 | /* Get priority to use, and set it. */ |
109 | if (use_relative) { |
110 | int old_priority; |
111 | |
112 | errno = 0; /* Needed for getpriority error detection. */ |
113 | old_priority = getpriority(which, who); |
114 | if (errno) { |
115 | bb_perror_msg(Xetpriority_msg, 'g'); |
116 | goto HAD_ERROR; |
117 | } |
118 | |
119 | new_priority = old_priority + adjustment; |
120 | } else { |
121 | new_priority = adjustment; |
122 | } |
123 | |
124 | if (setpriority(which, who, new_priority) == 0) { |
125 | continue; |
126 | } |
127 | |
128 | bb_perror_msg(Xetpriority_msg, 's'); |
129 | HAD_ERROR: |
130 | retval = EXIT_FAILURE; |
131 | } |
132 | |
133 | /* No need to check for errors outputing to stderr since, if it |
134 | * was used, the HAD_ERROR label was reached and retval was set. */ |
135 | |
136 | return retval; |
137 | } |
138 |