1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/* vi: set sw=4 ts=4: */
/*
* chrt - manipulate real-time attributes of a process
* Copyright (c) 2006-2007 Bernhard Reutner-Fischer
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config CHRT
//config: bool "chrt (4.4 kb)"
//config: default y
//config: help
//config: manipulate real-time attributes of a process.
//config: This requires sched_{g,s}etparam support in your libc.
//applet:IF_CHRT(APPLET(chrt, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_CHRT) += chrt.o
//usage:#define chrt_trivial_usage
//usage: "[-prfom] [PRIO] [PID | PROG ARGS]"
//usage:#define chrt_full_usage "\n\n"
//usage: "Change scheduling priority and class for a process\n"
//usage: "\n -p Operate on PID"
//usage: "\n -r Set SCHED_RR class"
//usage: "\n -f Set SCHED_FIFO class"
//usage: "\n -o Set SCHED_OTHER class"
//usage: "\n -m Show min/max priorities"
//usage:
//usage:#define chrt_example_usage
//usage: "$ chrt -r 4 sleep 900; x=$!\n"
//usage: "$ chrt -f -p 3 $x\n"
//usage: "You need CAP_SYS_NICE privileges to set scheduling attributes of a process"
#include <sched.h>
#include "libbb.h"
static const struct {
int policy;
char name[sizeof("SCHED_OTHER")];
} policies[] = {
{SCHED_OTHER, "SCHED_OTHER"},
{SCHED_FIFO, "SCHED_FIFO"},
{SCHED_RR, "SCHED_RR"}
};
//TODO: add
// -b, SCHED_BATCH
// -i, SCHED_IDLE
static void show_min_max(int pol)
{
const char *fmt = "%s min/max priority\t: %u/%u\n";
int max, min;
max = sched_get_priority_max(pol);
min = sched_get_priority_min(pol);
if ((max|min) < 0)
fmt = "%s not supported\n";
printf(fmt, policies[pol].name, min, max);
}
#define OPT_m (1<<0)
#define OPT_p (1<<1)
#define OPT_r (1<<2)
#define OPT_f (1<<3)
#define OPT_o (1<<4)
int chrt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chrt_main(int argc UNUSED_PARAM, char **argv)
{
pid_t pid = 0;
unsigned opt;
struct sched_param sp;
char *pid_str;
char *priority = priority; /* for compiler */
const char *current_new;
int policy = SCHED_RR;
/* only one policy accepted */
opt_complementary = "r--fo:f--ro:o--rf";
opt = getopt32(argv, "+mprfo");
if (opt & OPT_m) { /* print min/max and exit */
show_min_max(SCHED_FIFO);
show_min_max(SCHED_RR);
show_min_max(SCHED_OTHER);
fflush_stdout_and_exit(EXIT_SUCCESS);
}
if (opt & OPT_r)
policy = SCHED_RR;
if (opt & OPT_f)
policy = SCHED_FIFO;
if (opt & OPT_o)
policy = SCHED_OTHER;
argv += optind;
if (!argv[0])
bb_show_usage();
if (opt & OPT_p) {
pid_str = *argv++;
if (*argv) { /* "-p <priority> <pid> [...]" */
priority = pid_str;
pid_str = *argv;
}
/* else "-p <pid>", and *argv == NULL */
pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
} else {
priority = *argv++;
if (!*argv)
bb_show_usage();
}
current_new = "current\0new";
if (opt & OPT_p) {
int pol;
print_rt_info:
pol = sched_getscheduler(pid);
if (pol < 0)
bb_perror_msg_and_die("can't %cet pid %d's policy", 'g', (int)pid);
printf("pid %d's %s scheduling policy: %s\n",
pid, current_new, policies[pol].name);
if (sched_getparam(pid, &sp))
bb_perror_msg_and_die("can't get pid %d's attributes", (int)pid);
printf("pid %d's %s scheduling priority: %d\n",
(int)pid, current_new, sp.sched_priority);
if (!*argv) {
/* Either it was just "-p <pid>",
* or it was "-p <priority> <pid>" and we came here
* for the second time (see goto below) */
return EXIT_SUCCESS;
}
*argv = NULL;
current_new += 8;
}
/* from the manpage of sched_getscheduler:
[...] sched_priority can have a value in the range 0 to 99.
[...] SCHED_OTHER or SCHED_BATCH must be assigned static priority 0.
[...] SCHED_FIFO or SCHED_RR can have static priority in 1..99 range.
*/
sp.sched_priority = xstrtou_range(priority, 0, policy != SCHED_OTHER ? 1 : 0, 99);
if (sched_setscheduler(pid, policy, &sp) < 0)
bb_perror_msg_and_die("can't %cet pid %d's policy", 's', (int)pid);
if (!argv[0]) /* "-p <priority> <pid> [...]" */
goto print_rt_info;
BB_EXECVP_or_die(argv);
}
|
