1/* vi: set sw=4 ts=4: */ 2/* 3 * chrt - manipulate real-time attributes of a process 4 * Copyright (c) 2006-2007 Bernhard Fischer 5 * 6 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. 7 */ 8 9#include <sched.h> 10#include <getopt.h> /* optind */ 11#include "libbb.h" 12#ifndef _POSIX_PRIORITY_SCHEDULING 13#warning your system may be foobared 14#endif 15static const struct { 16 const int policy; 17 const char const name[12]; 18} policies[] = { 19 {SCHED_OTHER, "SCHED_OTHER"}, 20 {SCHED_FIFO, "SCHED_FIFO"}, 21 {SCHED_RR, "SCHED_RR"} 22}; 23 24static void show_min_max(int pol) 25{ 26 const char *fmt = "%s min/max priority\t: %d/%d\n\0%s not supported?\n"; 27 int max, min; 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); 32 else { 33 fmt += 29; 34 printf(fmt, policies[pol].name); 35 } 36} 37 38#define OPT_m (1<<0) 39#define OPT_p (1<<1) 40#define OPT_r (1<<2) 41#define OPT_f (1<<3) 42#define OPT_o (1<<4) 43 44int chrt_main(int argc, char** argv); 45int chrt_main(int argc, char** argv) 46{ 47 pid_t pid = 0; 48 unsigned opt; 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; 53 54 opt_complementary = "r--fo:f--ro:r--fo"; /* only one policy accepted */ 55 opt = getopt32(argv, "+mp:rfo", &p_opt); 56 if (opt & OPT_r) 57 policy = SCHED_RR; 58 if (opt & OPT_f) 59 policy = SCHED_FIFO; 60 if (opt & OPT_o) 61 policy = SCHED_OTHER; 62 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); 68 } 69 if (opt & OPT_p) { 70 if (argc == optind+1) { /* -p <priority> <pid> */ 71 priority = p_opt; 72 p_opt = argv[optind]; 73 } 74 argv += optind; /* me -p <arg> */ 75 pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */ 76 } else { 77 argv += optind; /* me -p <arg> */ 78 priority = *argv; 79 } 80 if (priority) { 81 /* from the manpage of sched_getscheduler: 82 [...] sched_priority can have a value 83 in the range 0 to 99. 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. 87 */ 88 prio = xstrtol_range(priority, 0, policy == SCHED_OTHER 89 ? 0 : 1, 99); 90 } 91 92 if (opt & OPT_p) { 93 int pol = 0; 94print_rt_info: 95 pol = sched_getscheduler(pid); 96 if (pol < 0) 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. */ 105 return EXIT_SUCCESS; 106 } 107 108 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); 111 if (opt & OPT_p) { 112 state += 8; 113 ++argv; 114 goto print_rt_info; 115 } 116 ++argv; 117 BB_EXECVP(*argv, argv); 118 bb_perror_msg_and_die("%s", *argv); 119} 120#undef OPT_p 121#undef OPT_r 122#undef OPT_f 123#undef OPT_o 124#undef OPT_m 125