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/* vi: set sw=4 ts=4: */
/*
* chrt - manipulate real-time attributes of a process
* Copyright (c) 2006-2007 Bernhard Fischer
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "busybox.h"
#include <unistd.h>
#include <sched.h>
#include <getopt.h> /* optind */
#ifndef _POSIX_PRIORITY_SCHEDULING
#warning your system may be foobared
#endif
static const struct {
const int policy;
const char const name[12];
} policies[] = {
{SCHED_OTHER, "SCHED_OTHER"},
{SCHED_FIFO, "SCHED_FIFO"},
{SCHED_RR, "SCHED_RR"}
};
static void show_min_max(int pol) {
const char *fmt = "%s min/max priority\t: %d/%d\n\0%s not supported?\n";
int max, min;
max = sched_get_priority_max(pol);
min = sched_get_priority_min(pol);
if (max >= 0 && min >= 0)
printf(fmt, policies[pol].name, min, max);
else {
fmt += 29;
printf(fmt, policies[pol].name);
}
}
#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);
int chrt_main(int argc, char** argv)
{
pid_t pid = 0;
unsigned opt;
struct sched_param sp;
char *p_opt = NULL, *priority = NULL;
const char *state = "current\0new";
int prio = 0, policy = SCHED_RR;
opt_complementary = "r--fo:f--ro:r--fo"; /* only one policy accepted */
opt = getopt32(argc, argv, "+mp:rfo", &p_opt);
if (opt & OPT_r)
policy = SCHED_RR;
if (opt & OPT_f)
policy = SCHED_FIFO;
if (opt & OPT_o)
policy = SCHED_OTHER;
if (opt & OPT_m) { /* print min/max */
show_min_max(SCHED_FIFO);
show_min_max(SCHED_RR);
show_min_max(SCHED_OTHER);
fflush_stdout_and_exit(EXIT_SUCCESS);
}
if (opt & OPT_p) {
if (argc == optind+1) { /* -p <priority> <pid> */
priority = p_opt;
p_opt = argv[optind];
}
argv += optind; /* me -p <arg> */
pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */
} else {
argv += optind; /* me -p <arg> */
priority = *argv;
}
if (priority) {
/* 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
the static priority 0. [...] SCHED_FIFO or
SCHED_RR can have a static priority in the range 1 to 99.
*/
prio = xstrtol_range(priority, 0, policy == SCHED_OTHER
? 0 : 1, 99);
}
if (opt & OPT_p) {
int pol = 0;
print_rt_info:
pol = sched_getscheduler(pid);
if (pol < 0)
bb_perror_msg_and_die("failed to %cet pid %d's policy", 'g', pid);
printf("pid %d's %s scheduling policy: %s\n",
pid, state, policies[pol].name);
if (sched_getparam(pid, &sp))
bb_perror_msg_and_die("failed to get pid %d's attributes", pid);
printf("pid %d's %s scheduling priority: %d\n",
pid, state, sp.sched_priority);
if (!*argv) /* no new prio given or we did print already, done. */
return EXIT_SUCCESS;
}
sp.sched_priority = prio;
if (sched_setscheduler(pid, policy, &sp) < 0)
bb_perror_msg_and_die("failed to %cet pid %d's policy", 's', pid);
if (opt & OPT_p) {
state += 8;
++argv;
goto print_rt_info;
}
++argv;
BB_EXECVP(*argv, argv);
bb_perror_msg_and_die("%s", *argv);
}
#undef OPT_p
#undef OPT_r
#undef OPT_f
#undef OPT_o
#undef OPT_m
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