xref: /freebsd/tools/regression/p1003_1b/sched.c (revision ae83180158c4c937f170e31eff311b18c0286a93)
1 /*
2  * Copyright (c) 1996-1999
3  *	HD Associates, Inc.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by HD Associates, Inc
16  * 4. Neither the name of the author nor the names of any co-contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  * $FreeBSD$
32  *
33  */
34 
35 /* XXX: The spec says that if _POSIX_C_SOURCE is defined then
36  *      _POSIX_SOURCE is ignored.  However, this is similar to
37  *      the code in the O'Reilly "POSIX.4" book
38  */
39 
40 #define _POSIX_VERSION 199309L
41 #define _POSIX_SOURCE
42 #define _POSIX_C_SOURCE 199309L
43 
44 #include <unistd.h>
45 #include <stdlib.h>
46 
47 #include <stdio.h>
48 #include <string.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <sys/mman.h>
52 
53 #include <sched.h>
54 
55 #include "prutil.h"
56 
57 static FILE *verbose;
58 
59 static void
60 checkpris(int sched)
61 {
62 	int smin;
63 	int smax;
64 
65 	errno = 0;
66 
67 	if ( (smin = sched_get_priority_min(sched)) == -1 && errno)
68 		quit("sched_get_priority_min");
69 
70 	if ( (smax = sched_get_priority_max(sched)) == -1 && errno)
71 		quit("sched_get_priority_max");
72 
73 	if (smax - smin + 1 < 32 || smax < smin) {
74 		fprintf(stderr, "Illegal priority range for %s: %d to %d\n",
75 		sched_text(sched), smin, smax);
76 		exit(-1);
77 	}
78 
79 	if (verbose)
80 		fprintf(verbose, "%12s: sched_min %2d sched_max %2d\n",
81 		sched_text(sched), smin, smax);
82 }
83 
84 /* Set "try_anyway" to quit if you don't want to go on when
85  * it doesn't look like something should work.
86  */
87 static void try_anyway(const char *s)
88 {
89 	fputs(s, stderr);
90 	fprintf(stderr, "(trying anyway)\n");
91 	errno = 0;
92 }
93 
94 static void q(int line, int code, const char *text)
95 {
96 	if (code == -1)
97 	{
98 		fprintf(stderr, "Error at line %d:\n", line);
99 		perror(text);
100 		exit(errno);
101 	}
102 }
103 
104 int sched(int ac, char *av[])
105 {
106 	int fifo_schedmin, fifo_schedmax;
107 	int i;
108 	struct sched_param rt_param;
109 	int n_instances = 10;
110 	int sched;
111 
112 	verbose = 0;
113 
114 #if _POSIX_VERSION < 199309
115 	try_anyway("The _POSIX_VERSION predates P1003.1B\n");
116 #endif
117 
118 #if !defined(_POSIX_PRIORITY_SCHEDULING)
119 	try_anyway(
120 	"The environment does not claim to support Posix scheduling.\n");
121 #endif
122 
123 	/* Is priority scheduling configured?
124 	 */
125 	errno = 0;
126 	if (sysconf(_SC_PRIORITY_SCHEDULING) == -1) {
127 		if (errno != 0) {
128 			/* This isn't valid - may be a standard violation
129 			 */
130 			quit("(should not happen) sysconf(_SC_PRIORITY_SCHEDULING)");
131 		}
132 		else {
133 			try_anyway(
134 			"The environment does not have run-time "
135 			"support for Posix scheduling.\n");
136 		}
137 	}
138 
139 	/* Check that the priorities seem reasonable.
140 	 */
141 
142 	checkpris(SCHED_FIFO);
143 	checkpris(SCHED_RR);
144 	checkpris(SCHED_OTHER);
145 
146 /* BSD extensions?
147  */
148 #if defined(SCHED_IDLE)
149 	checkpris(SCHED_IDLE);
150 #endif
151 
152 	fifo_schedmin = sched_get_priority_min(SCHED_FIFO);
153 	fifo_schedmax = sched_get_priority_max(SCHED_FIFO);
154 
155 	/* Make sure we can do some basic schedule switching:
156 	 */
157 	{
158 		struct sched_param orig_param, shouldbe;
159 		int orig_scheduler = sched_is(__LINE__, &orig_param, -1);
160 
161 		if (verbose)
162 			fprintf(verbose,
163 			"The original scheduler is %s and the priority is %d.\n",
164 			sched_text(orig_scheduler), orig_param.sched_priority);
165 
166 		/* Basic check: Try to set current settings:
167 		 */
168 		q(__LINE__, sched_setscheduler(0, orig_scheduler, &orig_param),
169 			"sched_setscheduler: Can't set original scheduler");
170 
171 		rt_param.sched_priority = fifo_schedmin;
172 
173 		q(__LINE__, sched_setscheduler(0, SCHED_FIFO, &rt_param),
174 		"sched_setscheduler SCHED_FIFO");
175 
176 		(void)sched_is(__LINE__, 0, SCHED_FIFO);
177 
178 		q(__LINE__, sched_getparam(0, &shouldbe), "sched_getparam");
179 
180 		if (shouldbe.sched_priority != fifo_schedmin)
181 			quit("sched_setscheduler wrong priority (min)");
182 
183 		rt_param.sched_priority = fifo_schedmin;
184 
185 		q(__LINE__, sched_setparam(0, &rt_param),
186 			"sched_setparam to fifo_schedmin");
187 
188 		rt_param.sched_priority = fifo_schedmin + 1;
189 
190 		q(__LINE__, sched_setparam(0, &rt_param),
191 			"sched_setparam to fifo_schedmin + 1");
192 
193 		q(__LINE__, sched_getparam(0, &shouldbe),
194 			"sched_getparam");
195 
196 		if (shouldbe.sched_priority != fifo_schedmin + 1)
197 			quit("sched_setscheduler wrong priority (min + 1)");
198 
199 		q(__LINE__, sched_setscheduler(0, SCHED_RR, &rt_param),
200 			"sched_setscheduler SCHED_RR");
201 
202 		(void)sched_is(__LINE__, 0, SCHED_RR);
203 
204 		q(__LINE__, sched_setscheduler(0, orig_scheduler, &orig_param),
205 			"sched_setscheduler restoring original scheduler");
206 
207 		(void)sched_is(__LINE__, 0, orig_scheduler);
208 	}
209 
210 
211 	{
212 #define NAM "P1003_1b_schedXXXX"
213 		char nam[L_tmpnam];
214 		int fd;
215 		pid_t p;
216 		pid_t *lastrun;
217 
218 		strcpy(nam, NAM);
219 		if (tmpnam(nam) != nam)
220 			q(__LINE__, errno, "tmpnam " NAM);
221 		q(__LINE__, (fd = open(nam, O_RDWR|O_CREAT, 0666)),
222 			"open " NAM);
223 
224 		(void)unlink(nam);
225 
226 		p = (pid_t)0;
227 
228 		write(fd, &p, sizeof(p));
229 
230 		q(__LINE__,  (int)(lastrun = mmap(0, sizeof(*lastrun), PROT_READ|PROT_WRITE,
231 		MAP_SHARED, fd, 0)), "mmap");
232 
233 		/* Set our priority at the highest:
234 		 */
235 		sched = SCHED_FIFO;
236 		rt_param.sched_priority = fifo_schedmax;
237 		q(__LINE__, sched_setscheduler(0, sched, &rt_param),
238 		"sched_setscheduler sched");
239 
240 		for (i = 0; i < n_instances; i++)
241 		{
242 			pid_t me;
243 
244 			/* XXX This is completely bogus.  The children never run.
245 			 */
246 			if ((me = fork()) != 0)
247 			{
248 				/* Parent.
249 				 */
250 				(void)sched_is(__LINE__, 0, sched);
251 
252 				/* Lower our priority:
253 				 */
254 				rt_param.sched_priority--;
255 
256 				q(__LINE__, sched_setscheduler(0, sched, &rt_param),
257 				"sched_setscheduler sched");
258 
259 				while (1)
260 				{
261 					q(__LINE__, sched_getparam(0, &rt_param), "sched_getparam");
262 
263 					rt_param.sched_priority--;
264 
265 
266 					if (rt_param.sched_priority < fifo_schedmin)
267 						exit(0);
268 
269 					*lastrun = me;
270 					q(__LINE__, sched_setparam(0, &rt_param), "sched_setparam");
271 
272 					if (*lastrun == me)
273 					{
274 						/* The child will run twice
275 						 * at  the end:
276 						 */
277 						if (!me || rt_param.sched_priority != 0)
278 						{
279 							fprintf(stderr,
280 							"ran process %ld twice at priority %d\n",
281 							(long)me, rt_param.sched_priority + 1);
282 							exit(-1);
283 						}
284 					}
285 				}
286 			}
287 		}
288 	}
289 
290 	return 0;
291 }
292 #ifdef STANDALONE_TESTS
293 int main(int argc, char *argv[]) { return sched(argc, argv); }
294 #endif
295