1 /* vi: set sw=4 ts=4: */
3 * chrt - manipulate real-time attributes of a process
4 * Copyright (c) 2006-2007 Bernhard Fischer
6 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
10 #include <getopt.h> /* optind */
12 #ifndef _POSIX_PRIORITY_SCHEDULING
13 #warning your system may be foobared
17 const char const name[12];
19 {SCHED_OTHER, "SCHED_OTHER"},
20 {SCHED_FIFO, "SCHED_FIFO"},
21 {SCHED_RR, "SCHED_RR"}
24 static void show_min_max(int pol)
26 const char *fmt = "%s min/max priority\t: %d/%d\n\0%s not supported?\n";
28 max = sched_get_priority_max(pol);
29 min = sched_get_priority_min(pol);
30 if (max >= 0 && min >= 0)
31 printf(fmt, policies[pol].name, min, max);
34 printf(fmt, policies[pol].name);
44 int chrt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
45 int chrt_main(int argc, char **argv)
49 struct sched_param sp;
50 char *p_opt = NULL, *priority = NULL;
51 const char *state = "current\0new";
52 int prio = 0, policy = SCHED_RR;
54 opt_complementary = "r--fo:f--ro:r--fo"; /* only one policy accepted */
55 opt = getopt32(argv, "+mp:rfo", &p_opt);
63 if (opt & OPT_m) { /* print min/max */
64 show_min_max(SCHED_FIFO);
65 show_min_max(SCHED_RR);
66 show_min_max(SCHED_OTHER);
67 fflush_stdout_and_exit(EXIT_SUCCESS);
70 if (argc == optind+1) { /* -p <priority> <pid> */
74 argv += optind; /* me -p <arg> */
75 pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */
77 argv += optind; /* me -p <arg> */
81 /* from the manpage of sched_getscheduler:
82 [...] sched_priority can have a value
84 [...] SCHED_OTHER or SCHED_BATCH must be assigned
85 the static priority 0. [...] SCHED_FIFO or
86 SCHED_RR can have a static priority in the range 1 to 99.
88 prio = xstrtol_range(priority, 0, policy == SCHED_OTHER
95 pol = sched_getscheduler(pid);
97 bb_perror_msg_and_die("failed to %cet pid %d's policy", 'g', pid);
98 printf("pid %d's %s scheduling policy: %s\n",
99 pid, state, policies[pol].name);
100 if (sched_getparam(pid, &sp))
101 bb_perror_msg_and_die("failed to get pid %d's attributes", pid);
102 printf("pid %d's %s scheduling priority: %d\n",
103 pid, state, sp.sched_priority);
104 if (!*argv) /* no new prio given or we did print already, done. */
108 sp.sched_priority = prio;
109 if (sched_setscheduler(pid, policy, &sp) < 0)
110 bb_perror_msg_and_die("failed to %cet pid %d's policy", 's', pid);
117 BB_EXECVP(*argv, argv);
118 bb_simple_perror_msg_and_die(*argv);