LXR busybox/miscutils/ionice.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * ionice implementation for busybox based on linux-utils-ng 2.14
   4 *
   5 * Copyright (C) 2008 by  <u173034@informatik.uni-oldenburg.de>
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8 */
   9
  10#include <sys/syscall.h>
  11#include <asm/unistd.h>
  12#include "libbb.h"
  13
  14static int ioprio_set(int which, int who, int ioprio)
  15{
  16        return syscall(SYS_ioprio_set, which, who, ioprio);
  17}
  18
  19static int ioprio_get(int which, int who)
  20{
  21        return syscall(SYS_ioprio_get, which, who);
  22}
  23
  24enum {
  25        IOPRIO_WHO_PROCESS = 1,
  26        IOPRIO_WHO_PGRP,
  27        IOPRIO_WHO_USER
  28};
  29
  30enum {
  31        IOPRIO_CLASS_NONE,
  32        IOPRIO_CLASS_RT,
  33        IOPRIO_CLASS_BE,
  34        IOPRIO_CLASS_IDLE
  35};
  36
  37static const char to_prio[] = "none\0realtime\0best-effort\0idle";
  38
  39#define IOPRIO_CLASS_SHIFT      13
  40
  41int ionice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  42int ionice_main(int argc UNUSED_PARAM, char **argv)
  43{
  44        /* Defaults */
  45        int ioclass = 0;
  46        int pri = 0;
  47        int pid = 0; /* affect own porcess */
  48        int opt;
  49        enum {
  50                OPT_n = 1,
  51                OPT_c = 2,
  52                OPT_p = 4,
  53        };
  54
  55        /* Numeric params */
  56        opt_complementary = "n+:c+:p+";
  57        /* '+': stop at first non-option */
  58        opt = getopt32(argv, "+n:c:p:", &pri, &ioclass, &pid);
  59        argv += optind;
  60
  61        if (opt & OPT_c) {
  62                if (ioclass > 3)
  63                        bb_error_msg_and_die("bad class %d", ioclass);
  64// Do we need this (compat?)?
  65//              if (ioclass == IOPRIO_CLASS_NONE)
  66//                      ioclass = IOPRIO_CLASS_BE;
  67//              if (ioclass == IOPRIO_CLASS_IDLE) {
  68//                      //if (opt & OPT_n)
  69//                      //      bb_error_msg("ignoring priority for idle class");
  70//                      pri = 7;
  71//              }
  72        }
  73
  74        if (!(opt & (OPT_n|OPT_c))) {
  75                if (!(opt & OPT_p) && *argv)
  76                        pid = xatoi_positive(*argv);
  77
  78                pri = ioprio_get(IOPRIO_WHO_PROCESS, pid);
  79                if (pri == -1)
  80                        bb_perror_msg_and_die("ioprio_%cet", 'g');
  81
  82                ioclass = (pri >> IOPRIO_CLASS_SHIFT) & 0x3;
  83                pri &= 0xff;
  84                printf((ioclass == IOPRIO_CLASS_IDLE) ? "%s\n" : "%s: prio %d\n",
  85                                nth_string(to_prio, ioclass), pri);
  86        } else {
  87//printf("pri=%d class=%d val=%x\n",
  88//pri, ioclass, pri | (ioclass << IOPRIO_CLASS_SHIFT));
  89                pri |= (ioclass << IOPRIO_CLASS_SHIFT);
  90                if (ioprio_set(IOPRIO_WHO_PROCESS, pid, pri) == -1)
  91                        bb_perror_msg_and_die("ioprio_%cet", 's');
  92                if (argv[0]) {
  93                        BB_EXECVP_or_die(argv);
  94                }
  95        }
  96
  97        return EXIT_SUCCESS;
  98}
  99