1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Use the core scheduling prctl() to test core scheduling cookies control.
4  *
5  * Copyright (c) 2021 Oracle and/or its affiliates.
6  * Author: Chris Hyser <chris.hyser@oracle.com>
7  *
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of version 2.1 of the GNU Lesser General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This library is distributed in the hope that it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
16  * for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public License
19  * along with this library; if not, see <http://www.gnu.org/licenses>.
20  */
21 
22 #define _GNU_SOURCE
23 #include <sys/eventfd.h>
24 #include <sys/wait.h>
25 #include <sys/types.h>
26 #include <sched.h>
27 #include <sys/prctl.h>
28 #include <unistd.h>
29 #include <time.h>
30 #include <errno.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 
35 #if __GLIBC_PREREQ(2, 30) == 0
36 #include <sys/syscall.h>
gettid(void)37 static pid_t gettid(void)
38 {
39 	return syscall(SYS_gettid);
40 }
41 #endif
42 
43 #ifndef PR_SCHED_CORE
44 #define PR_SCHED_CORE			62
45 # define PR_SCHED_CORE_GET		0
46 # define PR_SCHED_CORE_CREATE		1 /* create unique core_sched cookie */
47 # define PR_SCHED_CORE_SHARE_TO		2 /* push core_sched cookie to pid */
48 # define PR_SCHED_CORE_SHARE_FROM	3 /* pull core_sched cookie to pid */
49 # define PR_SCHED_CORE_MAX		4
50 #endif
51 
52 #define MAX_PROCESSES 128
53 #define MAX_THREADS   128
54 
55 static const char USAGE[] = "cs_prctl_test [options]\n"
56 "    options:\n"
57 "	-P  : number of processes to create.\n"
58 "	-T  : number of threads per process to create.\n"
59 "	-d  : delay time to keep tasks alive.\n"
60 "	-k  : keep tasks alive until keypress.\n";
61 
62 enum pid_type {PIDTYPE_PID = 0, PIDTYPE_TGID, PIDTYPE_PGID};
63 
64 const int THREAD_CLONE_FLAGS = CLONE_THREAD | CLONE_SIGHAND | CLONE_FS | CLONE_VM | CLONE_FILES;
65 
66 struct child_args {
67 	int num_threads;
68 	int pfd[2];
69 	int cpid;
70 	int thr_tids[MAX_THREADS];
71 };
72 
73 static struct child_args procs[MAX_PROCESSES];
74 static int num_processes = 2;
75 static int need_cleanup = 0;
76 
_prctl(int option,unsigned long arg2,unsigned long arg3,unsigned long arg4,unsigned long arg5)77 static int _prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4,
78 		  unsigned long arg5)
79 {
80 	int res;
81 
82 	res = prctl(option, arg2, arg3, arg4, arg5);
83 	printf("%d = prctl(%d, %ld, %ld, %ld, %lx)\n", res, option, (long)arg2, (long)arg3,
84 	       (long)arg4, arg5);
85 	return res;
86 }
87 
88 #define STACK_SIZE (1024 * 1024)
89 
90 #define handle_error(msg) __handle_error(__FILE__, __LINE__, msg)
__handle_error(char * fn,int ln,char * msg)91 static void __handle_error(char *fn, int ln, char *msg)
92 {
93 	int pidx;
94 	printf("(%s:%d) - ", fn, ln);
95 	perror(msg);
96 	if (need_cleanup) {
97 		for (pidx = 0; pidx < num_processes; ++pidx)
98 			kill(procs[pidx].cpid, 15);
99 		need_cleanup = 0;
100 	}
101 	exit(EXIT_FAILURE);
102 }
103 
handle_usage(int rc,char * msg)104 static void handle_usage(int rc, char *msg)
105 {
106 	puts(USAGE);
107 	puts(msg);
108 	putchar('\n');
109 	exit(rc);
110 }
111 
get_cs_cookie(int pid)112 static unsigned long get_cs_cookie(int pid)
113 {
114 	unsigned long long cookie;
115 	int ret;
116 
117 	ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid, PIDTYPE_PID,
118 		    (unsigned long)&cookie);
119 	if (ret) {
120 		printf("Not a core sched system\n");
121 		return -1UL;
122 	}
123 
124 	return cookie;
125 }
126 
child_func_thread(void * arg)127 static int child_func_thread(void __attribute__((unused))*arg)
128 {
129 	while (1)
130 		usleep(20000);
131 	return 0;
132 }
133 
create_threads(int num_threads,int thr_tids[])134 static void create_threads(int num_threads, int thr_tids[])
135 {
136 	void *child_stack;
137 	pid_t tid;
138 	int i;
139 
140 	for (i = 0; i < num_threads; ++i) {
141 		child_stack = malloc(STACK_SIZE);
142 		if (!child_stack)
143 			handle_error("child stack allocate");
144 
145 		tid = clone(child_func_thread, child_stack + STACK_SIZE, THREAD_CLONE_FLAGS, NULL);
146 		if (tid == -1)
147 			handle_error("clone thread");
148 		thr_tids[i] = tid;
149 	}
150 }
151 
child_func_process(void * arg)152 static int child_func_process(void *arg)
153 {
154 	struct child_args *ca = (struct child_args *)arg;
155 	int ret;
156 
157 	close(ca->pfd[0]);
158 
159 	create_threads(ca->num_threads, ca->thr_tids);
160 
161 	ret = write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads);
162 	if (ret == -1)
163 		printf("write failed on pfd[%d] - error (%s)\n",
164 			ca->pfd[1], strerror(errno));
165 
166 	close(ca->pfd[1]);
167 
168 	while (1)
169 		usleep(20000);
170 	return 0;
171 }
172 
173 static unsigned char child_func_process_stack[STACK_SIZE];
174 
create_processes(int num_processes,int num_threads,struct child_args proc[])175 void create_processes(int num_processes, int num_threads, struct child_args proc[])
176 {
177 	pid_t cpid;
178 	int i, ret;
179 
180 	for (i = 0; i < num_processes; ++i) {
181 		proc[i].num_threads = num_threads;
182 
183 		if (pipe(proc[i].pfd) == -1)
184 			handle_error("pipe() failed");
185 
186 		cpid = clone(child_func_process, child_func_process_stack + STACK_SIZE,
187 			     SIGCHLD, &proc[i]);
188 		proc[i].cpid = cpid;
189 		close(proc[i].pfd[1]);
190 	}
191 
192 	for (i = 0; i < num_processes; ++i) {
193 		ret = read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads);
194 		if (ret == -1)
195 			printf("read failed on proc[%d].pfd[0] error (%s)\n",
196 				i, strerror(errno));
197 		close(proc[i].pfd[0]);
198 	}
199 }
200 
disp_processes(int num_processes,struct child_args proc[])201 void disp_processes(int num_processes, struct child_args proc[])
202 {
203 	int i, j;
204 
205 	printf("tid=%d, / tgid=%d / pgid=%d: %lx\n", gettid(), getpid(), getpgid(0),
206 	       get_cs_cookie(getpid()));
207 
208 	for (i = 0; i < num_processes; ++i) {
209 		printf("    tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].cpid, proc[i].cpid,
210 		       getpgid(proc[i].cpid), get_cs_cookie(proc[i].cpid));
211 		for (j = 0; j < proc[i].num_threads; ++j) {
212 			printf("        tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].thr_tids[j],
213 			       proc[i].cpid, getpgid(0), get_cs_cookie(proc[i].thr_tids[j]));
214 		}
215 	}
216 	puts("\n");
217 }
218 
219 static int errors;
220 
221 #define validate(v) _validate(__LINE__, v, #v)
_validate(int line,int val,char * msg)222 void _validate(int line, int val, char *msg)
223 {
224 	if (!val) {
225 		++errors;
226 		printf("(%d) FAILED: %s\n", line, msg);
227 	} else {
228 		printf("(%d) PASSED: %s\n", line, msg);
229 	}
230 }
231 
main(int argc,char * argv[])232 int main(int argc, char *argv[])
233 {
234 	int keypress = 0;
235 	int num_threads = 3;
236 	int delay = 0;
237 	int res = 0;
238 	int pidx;
239 	int pid;
240 	int opt;
241 
242 	while ((opt = getopt(argc, argv, ":hkT:P:d:")) != -1) {
243 		switch (opt) {
244 		case 'P':
245 			num_processes = (int)strtol(optarg, NULL, 10);
246 			break;
247 		case 'T':
248 			num_threads = (int)strtoul(optarg, NULL, 10);
249 			break;
250 		case 'd':
251 			delay = (int)strtol(optarg, NULL, 10);
252 			break;
253 		case 'k':
254 			keypress = 1;
255 			break;
256 		case 'h':
257 			printf(USAGE);
258 			exit(EXIT_SUCCESS);
259 		default:
260 			handle_usage(20, "unknown option");
261 		}
262 	}
263 
264 	if (num_processes < 1 || num_processes > MAX_PROCESSES)
265 		handle_usage(1, "Bad processes value");
266 
267 	if (num_threads < 1 || num_threads > MAX_THREADS)
268 		handle_usage(2, "Bad thread value");
269 
270 	if (keypress)
271 		delay = -1;
272 
273 	srand(time(NULL));
274 
275 	/* put into separate process group */
276 	if (setpgid(0, 0) != 0)
277 		handle_error("process group");
278 
279 	printf("\n## Create a thread/process/process group hiearchy\n");
280 	create_processes(num_processes, num_threads, procs);
281 	need_cleanup = 1;
282 	disp_processes(num_processes, procs);
283 	validate(get_cs_cookie(0) == 0);
284 
285 	printf("\n## Set a cookie on entire process group\n");
286 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 0, PIDTYPE_PGID, 0) < 0)
287 		handle_error("core_sched create failed -- PGID");
288 	disp_processes(num_processes, procs);
289 
290 	validate(get_cs_cookie(0) != 0);
291 
292 	/* get a random process pid */
293 	pidx = rand() % num_processes;
294 	pid = procs[pidx].cpid;
295 
296 	validate(get_cs_cookie(0) == get_cs_cookie(pid));
297 	validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));
298 
299 	printf("\n## Set a new cookie on entire process/TGID [%d]\n", pid);
300 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, pid, PIDTYPE_TGID, 0) < 0)
301 		handle_error("core_sched create failed -- TGID");
302 	disp_processes(num_processes, procs);
303 
304 	validate(get_cs_cookie(0) != get_cs_cookie(pid));
305 	validate(get_cs_cookie(pid) != 0);
306 	validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));
307 
308 	printf("\n## Copy the cookie of current/PGID[%d], to pid [%d] as PIDTYPE_PID\n",
309 	       getpid(), pid);
310 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, pid, PIDTYPE_PID, 0) < 0)
311 		handle_error("core_sched share to itself failed -- PID");
312 	disp_processes(num_processes, procs);
313 
314 	validate(get_cs_cookie(0) == get_cs_cookie(pid));
315 	validate(get_cs_cookie(pid) != 0);
316 	validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));
317 
318 	printf("\n## Copy cookie from a thread [%d] to current/PGID [%d] as PIDTYPE_PID\n",
319 	       procs[pidx].thr_tids[0], getpid());
320 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, procs[pidx].thr_tids[0],
321 		   PIDTYPE_PID, 0) < 0)
322 		handle_error("core_sched share from thread failed -- PID");
323 	disp_processes(num_processes, procs);
324 
325 	validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));
326 	validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));
327 
328 	printf("\n## Copy cookie from current [%d] to current as pidtype PGID\n", getpid());
329 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 0) < 0)
330 		handle_error("core_sched share to self failed -- PGID");
331 	disp_processes(num_processes, procs);
332 
333 	validate(get_cs_cookie(0) == get_cs_cookie(pid));
334 	validate(get_cs_cookie(pid) != 0);
335 	validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));
336 
337 	validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_MAX, 0, PIDTYPE_PGID, 0) < 0
338 		&& errno == EINVAL);
339 
340 	validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 1) < 0
341 		&& errno == EINVAL);
342 
343 	if (errors) {
344 		printf("TESTS FAILED. errors: %d\n", errors);
345 		res = 10;
346 	} else {
347 		printf("SUCCESS !!!\n");
348 	}
349 
350 	if (keypress)
351 		getchar();
352 	else
353 		sleep(delay);
354 
355 	for (pidx = 0; pidx < num_processes; ++pidx)
356 		kill(procs[pidx].cpid, 15);
357 
358 	return res;
359 }
360