xref: /illumos-gate/usr/src/test/os-tests/tests/ucontext.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2022 OmniOS Community Edition (OmniOSce) Association.
14  */
15 
16 #include <atomic.h>
17 #include <err.h>
18 #include <pthread.h>
19 #include <stdint.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <ucontext.h>
23 #include <unistd.h>
24 #include <sys/debug.h>
25 #include <sys/types.h>
26 
27 static __thread uint64_t tlsvar;
28 static ucontext_t ctx;
29 static uint32_t failures;
30 static pthread_t tid;
31 
32 #define	THREAD1_VALUE	0x1010
33 #define	THREAD2_VALUE	0x0202
34 
35 void
36 report(char *tag)
37 {
38 	pthread_t ltid = pthread_self();
39 
40 	printf("  %-14s: thread=%x, TLS variable=%x\n",
41 	    tag, (uint_t)ltid, tlsvar);
42 }
43 
44 void
45 run(void)
46 {
47 	pthread_t ltid = pthread_self();
48 
49 	printf("Coroutine started from second thread\n");
50 	report("coroutine");
51 
52 	if (ltid != tid) {
53 		fprintf(stderr,
54 		    "FAIL: coroutine thread ID is %x, expected %x\n",
55 		    ltid, tid);
56 		atomic_inc_32(&failures);
57 	}
58 
59 	if (tlsvar != THREAD2_VALUE) {
60 		fprintf(stderr,
61 		    "FAIL: coroutine TLS variable is %x, expected %x\n",
62 		    tlsvar, THREAD2_VALUE);
63 		atomic_inc_32(&failures);
64 	}
65 }
66 
67 void *
68 thread(void *arg __unused)
69 {
70 	tlsvar = THREAD2_VALUE;
71 
72 	report("second thread");
73 	/*
74 	 * setcontext() does not return if successful, checking the return
75 	 * value upsets smatch.
76 	 */
77 	(void) setcontext(&ctx);
78 	errx(EXIT_FAILURE, "setcontext() returned and should not have.");
79 
80 	return (NULL);
81 }
82 
83 int
84 main(void)
85 {
86 	char stk[SIGSTKSZ];
87 	void *status;
88 
89 	tlsvar = THREAD1_VALUE;
90 
91 	report("main thread");
92 
93 	VERIFY0(getcontext(&ctx));
94 	ctx.uc_link = NULL;
95 	ctx.uc_stack.ss_sp = stk;
96 	ctx.uc_stack.ss_size = sizeof (stk);
97 	makecontext(&ctx, run, 0);
98 
99 	VERIFY0(pthread_create(&tid, NULL, thread, NULL));
100 	VERIFY0(pthread_join(tid, &status));
101 
102 	return (failures == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
103 }
104