| /* 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. |
| */ |
| |
| //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" |
| #ifndef _POSIX_PRIORITY_SCHEDULING |
| #warning your system may be foobared |
| #endif |
| |
| 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); |
| } |