xref: /illumos-gate/usr/src/test/os-tests/tests/eventfd.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 2021 OmniOS Community Edition (OmniOSce) Association.
14  */
15 
16 #include <err.h>
17 #include <errno.h>
18 #include <limits.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <sys/debug.h>
22 #include <sys/eventfd.h>
23 #include <unistd.h>
24 
25 static int
26 readn(int fd, uint_t n)
27 {
28 	uint_t i;
29 	int failures = 0;
30 
31 	for (i = 0; i < n; i++) {
32 		eventfd_t v = 0xdeadbeef;
33 		int ret;
34 
35 		ret = eventfd_read(fd, &v);
36 		if (ret != 0) {
37 			warn("Reading %u/%u got ret %d (expected 0)",
38 			    i + 1, n, ret);
39 			failures++;
40 		} else if (v != 1) {
41 			warnx("Reading %u/%u got value %"PRIu64" (expected 1)",
42 			    i + 1, n, v);
43 			failures++;
44 		}
45 	}
46 
47 	return (failures);
48 }
49 
50 static int
51 check_nosem(int fd)
52 {
53 	eventfd_t v = 0xdeadbeef;
54 	int failures = 0;
55 	int ret;
56 
57 	ret = eventfd_read(fd, &v);
58 
59 	if (ret != -1) {
60 		warnx("no semaphores read got ret %d (expected -1)", ret);
61 		failures++;
62 	}
63 
64 	if (errno != EAGAIN) {
65 		warn("no semaphores read expected EAGAIN but got");
66 		failures++;
67 	}
68 
69 	if (v != 0xdeadbeef) {
70 		warnx("no semaphores read modified value to %"PRIx64, v);
71 		failures++;
72 	}
73 
74 	return (failures);
75 }
76 
77 static int
78 check_badwrite(int fd)
79 {
80 	int failures = 0;
81 	int ret;
82 
83 	ret = eventfd_write(fd, ULLONG_MAX);
84 
85 	if (ret != -1) {
86 		warnx("bad write got ret %d (expected -1)", ret);
87 		failures++;
88 	}
89 
90 	if (errno != EINVAL) {
91 		warn("bad write expected EINVAL but got");
92 		failures++;
93 	}
94 
95 	return (failures);
96 }
97 
98 int
99 main(void)
100 {
101 	int fd, failures = 0;
102 
103 	/* Test eventfd semaphore semantics */
104 	fd = eventfd(2, EFD_NONBLOCK | EFD_CLOEXEC | EFD_SEMAPHORE);
105 	if (fd == -1)
106 		err(EXIT_FAILURE, "Could not create eventfd semaphore");
107 
108 	/* Consume the available semaphores */
109 	failures += readn(fd, 2);
110 
111 	/* The next read should return -1/EAGAIN */
112 	failures += check_nosem(fd);
113 
114 	/* Return two + three semaphores */
115 	if (eventfd_write(fd, 2) != 0) {
116 		warn("Error while returning two semaphores");
117 		failures++;
118 	}
119 	if (eventfd_write(fd, 3) != 0) {
120 		warn("Error while returning three semaphores");
121 		failures++;
122 	}
123 
124 	/* Consume the available semaphores */
125 	failures += readn(fd, 5);
126 
127 	/* The next read should return -1/EAGAIN */
128 	failures += check_nosem(fd);
129 
130 	/*
131 	 * Check that a writing too large a value results in an error from
132 	 * eventfd_write() - testing that an error from the underlying write()
133 	 * is passed back.
134 	 */
135 	failures += check_badwrite(fd);
136 
137 	VERIFY0(close(fd));
138 
139 	return (failures == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
140 }
141