/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1996-1999
* HD Associates, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by HD Associates, Inc
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/* XXX: The spec says that if _POSIX_C_SOURCE is defined then
* _POSIX_SOURCE is ignored. However, this is similar to
* the code in the O'Reilly "POSIX.4" book
*/
#define _POSIX_VERSION 199309L
#define _POSIX_SOURCE
#define _POSIX_C_SOURCE 199309L
#include <sys/mman.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <sched.h>
#include <stdio.h>
#define __XSI_VISIBLE 1
#include <stdlib.h>
#undef __XSI_VISIBLE
#include <string.h>
#include <unistd.h>
#include "prutil.h"
static FILE *verbose;
static void
checkpris(int sched)
{
int smin;
int smax;
errno = 0;
if ( (smin = sched_get_priority_min(sched)) == -1 && errno)
quit("sched_get_priority_min");
if ( (smax = sched_get_priority_max(sched)) == -1 && errno)
quit("sched_get_priority_max");
if (smax - smin + 1 < 32 || smax < smin) {
fprintf(stderr, "Illegal priority range for %s: %d to %d\n",
sched_text(sched), smin, smax);
exit(-1);
}
if (verbose)
fprintf(verbose, "%12s: sched_min %2d sched_max %2d\n",
sched_text(sched), smin, smax);
}
/* Set "try_anyway" to quit if you don't want to go on when
* it doesn't look like something should work.
*/
static void try_anyway(const char *s)
{
fputs(s, stderr);
fprintf(stderr, "(trying anyway)\n");
errno = 0;
}
static void q(int line, int code, const char *text)
{
if (code == -1)
{
fprintf(stderr, "Error at line %d:\n", line);
perror(text);
exit(errno);
}
}
int sched(int ac, char *av[])
{
int fifo_schedmin, fifo_schedmax;
int i;
struct sched_param rt_param;
int n_instances = 10;
int sched;
verbose = 0;
#if _POSIX_VERSION < 199309
try_anyway("The _POSIX_VERSION predates P1003.1B\n");
#endif
#if !defined(_POSIX_PRIORITY_SCHEDULING)
try_anyway(
"The environment does not claim to support Posix scheduling.\n");
#endif
/* Is priority scheduling configured?
*/
errno = 0;
if (sysconf(_SC_PRIORITY_SCHEDULING) == -1) {
if (errno != 0) {
/* This isn't valid - may be a standard violation
*/
quit("(should not happen) sysconf(_SC_PRIORITY_SCHEDULING)");
}
else {
try_anyway(
"The environment does not have run-time "
"support for Posix scheduling.\n");
}
}
/* Check that the priorities seem reasonable.
*/
checkpris(SCHED_FIFO);
checkpris(SCHED_RR);
checkpris(SCHED_OTHER);
/* BSD extensions?
*/
#if defined(SCHED_IDLE)
checkpris(SCHED_IDLE);
#endif
fifo_schedmin = sched_get_priority_min(SCHED_FIFO);
fifo_schedmax = sched_get_priority_max(SCHED_FIFO);
/* Make sure we can do some basic schedule switching:
*/
{
struct sched_param orig_param, shouldbe;
int orig_scheduler = sched_is(__LINE__, &orig_param, -1);
if (verbose)
fprintf(verbose,
"The original scheduler is %s and the priority is %d.\n",
sched_text(orig_scheduler), orig_param.sched_priority);
/* Basic check: Try to set current settings:
*/
q(__LINE__, sched_setscheduler(0, orig_scheduler, &orig_param),
"sched_setscheduler: Can't set original scheduler");
rt_param.sched_priority = fifo_schedmin;
q(__LINE__, sched_setscheduler(0, SCHED_FIFO, &rt_param),
"sched_setscheduler SCHED_FIFO");
(void)sched_is(__LINE__, 0, SCHED_FIFO);
q(__LINE__, sched_getparam(0, &shouldbe), "sched_getparam");
if (shouldbe.sched_priority != fifo_schedmin)
quit("sched_setscheduler wrong priority (min)");
rt_param.sched_priority = fifo_schedmin;
q(__LINE__, sched_setparam(0, &rt_param),
"sched_setparam to fifo_schedmin");
rt_param.sched_priority = fifo_schedmin + 1;
q(__LINE__, sched_setparam(0, &rt_param),
"sched_setparam to fifo_schedmin + 1");
q(__LINE__, sched_getparam(0, &shouldbe),
"sched_getparam");
if (shouldbe.sched_priority != fifo_schedmin + 1)
quit("sched_setscheduler wrong priority (min + 1)");
q(__LINE__, sched_setscheduler(0, SCHED_RR, &rt_param),
"sched_setscheduler SCHED_RR");
(void)sched_is(__LINE__, 0, SCHED_RR);
q(__LINE__, sched_setscheduler(0, orig_scheduler, &orig_param),
"sched_setscheduler restoring original scheduler");
(void)sched_is(__LINE__, 0, orig_scheduler);
}
{
char nam[] = "P1003_1b_schedXXXXXX";
int fd;
pid_t p;
pid_t *lastrun;
fd = mkstemp(nam);
if (fd == -1)
q(__LINE__, errno, "mkstemp failed");
(void)unlink(nam);
p = (pid_t)0;
write(fd, &p, sizeof(p));
q(__LINE__, (int)(lastrun = mmap(0, sizeof(*lastrun), PROT_READ|PROT_WRITE,
MAP_SHARED, fd, 0)), "mmap");
/* Set our priority at the highest:
*/
sched = SCHED_FIFO;
rt_param.sched_priority = fifo_schedmax;
q(__LINE__, sched_setscheduler(0, sched, &rt_param),
"sched_setscheduler sched");
for (i = 0; i < n_instances; i++)
{
pid_t me;
/* XXX This is completely bogus. The children never run.
*/
if ((me = fork()) != 0)
{
/* Parent.
*/
(void)sched_is(__LINE__, 0, sched);
/* Lower our priority:
*/
rt_param.sched_priority--;
q(__LINE__, sched_setscheduler(0, sched, &rt_param),
"sched_setscheduler sched");
while (1)
{
q(__LINE__, sched_getparam(0, &rt_param), "sched_getparam");
rt_param.sched_priority--;
if (rt_param.sched_priority < fifo_schedmin)
exit(0);
*lastrun = me;
q(__LINE__, sched_setparam(0, &rt_param), "sched_setparam");
if (*lastrun == me)
{
/* The child will run twice
* at the end:
*/
if (!me || rt_param.sched_priority != 0)
{
fprintf(stderr,
"ran process %ld twice at priority %d\n",
(long)me, rt_param.sched_priority + 1);
exit(-1);
}
}
}
}
}
}
return 0;
}
#ifdef STANDALONE_TESTS
int main(int argc, char *argv[]) { return sched(argc, argv); }
#endif
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