busybox/miscutils/ionice.c

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/* vi: set sw=4 ts=4: */
/*
* ionice implementation for busybox based on linux-utils-ng 2.14
*
* Copyright (C) 2008 by <u173034@informatik.uni-oldenburg.de>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <sys/syscall.h>
#include <asm/unistd.h>
#include "libbb.h"
static int ioprio_set(int which, int who, int ioprio)
{
return syscall(SYS_ioprio_set, which, who, ioprio);
}
static int ioprio_get(int which, int who)
{
return syscall(SYS_ioprio_get, which, who);
}
enum {
IOPRIO_WHO_PROCESS = 1,
IOPRIO_WHO_PGRP,
IOPRIO_WHO_USER
};
enum {
IOPRIO_CLASS_NONE,
IOPRIO_CLASS_RT,
IOPRIO_CLASS_BE,
IOPRIO_CLASS_IDLE
};
static const char to_prio[] = "none\0realtime\0best-effort\0idle";
#define IOPRIO_CLASS_SHIFT 13
int ionice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ionice_main(int argc UNUSED_PARAM, char **argv)
{
/* Defaults */
int ioclass = 0;
int pri = 0;
int pid = 0; /* affect own porcess */
int opt;
enum {
OPT_n = 1,
OPT_c = 2,
OPT_p = 4,
};
/* Numeric params */
opt_complementary = "n+:c+:p+";
/* '+': stop at first non-option */
opt = getopt32(argv, "+n:c:p:", &pri, &ioclass, &pid);
argv += optind;
if (opt & OPT_c) {
if (ioclass > 3)
bb_error_msg_and_die("bad class %d", ioclass);
// Do we need this (compat?)?
// if (ioclass == IOPRIO_CLASS_NONE)
// ioclass = IOPRIO_CLASS_BE;
// if (ioclass == IOPRIO_CLASS_IDLE) {
// //if (opt & OPT_n)
// // bb_error_msg("ignoring priority for idle class");
// pri = 7;
// }
}
if (!(opt & (OPT_n|OPT_c))) {
if (!(opt & OPT_p) && *argv)
pid = xatoi_u(*argv);
pri = ioprio_get(IOPRIO_WHO_PROCESS, pid);
if (pri == -1)
bb_perror_msg_and_die("ioprio_%cet", 'g');
ioclass = (pri >> IOPRIO_CLASS_SHIFT) & 0x3;
pri &= 0xff;
printf((ioclass == IOPRIO_CLASS_IDLE) ? "%s\n" : "%s: prio %d\n",
nth_string(to_prio, ioclass), pri);
} else {
//printf("pri=%d class=%d val=%x\n",
//pri, ioclass, pri | (ioclass << IOPRIO_CLASS_SHIFT));
pri |= (ioclass << IOPRIO_CLASS_SHIFT);
if (ioprio_set(IOPRIO_WHO_PROCESS, pid, pri) == -1)
bb_perror_msg_and_die("ioprio_%cet", 's');
if (*argv) {
BB_EXECVP(*argv, argv);
bb_simple_perror_msg_and_die(*argv);
}
}
return EXIT_SUCCESS;
}