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/* Copyright 2016, Richard Lowe. */
13
14#include <sys/select.h>
15#include <sys/stat.h>
16#include <sys/time.h>
17#include <sys/types.h>
18
19#include <err.h>
20#include <errno.h>
21#include <fcntl.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <unistd.h>
26
27void
28diff_sets(fd_set *a, fd_set *b, size_t size)
29{
30	for (int i = 0; i < size; i++) {
31		if (FD_ISSET(i, a) != FD_ISSET(i, b))
32			printf("fd %d: %d should be %d\n", i, FD_ISSET(i, a),
33			    FD_ISSET(i, b));
34	}
35}
36
37void
38print_set(fd_set *a, size_t size)
39{
40	for (int i = 0; i < size; i++) {
41		if (FD_ISSET(i, a))
42			(void) putc('1', stdout);
43		else
44			(void) putc('0', stdout);
45	}
46
47	(void) putc('\n', stdout);
48}
49
50int
51main(int argc, char **argv)
52{
53	struct timeval tv = {0, 0};
54	fd_set check, proto;
55	fd_set *sread = NULL, *swrite = NULL, *serr = NULL;
56	int null, zero, maxfd = -1, nfds;
57	char buf[1];
58
59	if (argc != 2)
60		errx(1, "usage: select_test <number of fds>");
61
62	nfds = atoi(argv[1]);
63	if (errno != 0)
64		err(1, "couldn't convert %s to int", argv[1]);
65
66	if (nfds > FD_SETSIZE)
67		errx(1, "can't have more fds than FD_SETSIZE %d", FD_SETSIZE);
68
69	FD_ZERO(&proto);
70	FD_ZERO(&check);
71
72	switch (arc4random_uniform(3)) {
73	case 0:
74		sread = &check;
75		break;
76	case 1:
77		swrite = &check;
78		break;
79	case 2:
80		serr = &check;
81		break;
82	}
83
84	closefrom(3);
85
86	if ((null = open("/dev/null", O_RDONLY)) == -1)
87		err(1, "couldn't open /dev/null");
88	if (read(null, &buf, 1) < 0)
89		err(1, "failed to read fd");
90	if (read(null, &buf, 1) < 0)
91		err(1, "failed to read fd");
92
93	if ((zero = open("/dev/zero", O_RDWR)) == -1)
94		err(1, "couldn't open /dev/zero");
95
96	for (int i = zero; i < (zero + nfds); i++) {
97		int fd = (serr != NULL) ? null : zero;
98		if (arc4random_uniform(100) > 90) {
99			FD_SET(i, &proto);
100		}
101
102		if (dup2(fd, i) == -1)
103			err(1, "couldn't dup fd to fd %d", i);
104		maxfd = i;
105	}
106
107	if (swrite != NULL)
108		(void) puts("write");
109	else if (sread != NULL)
110		(void) puts("read");
111	else if (serr != NULL)
112		(void) puts("err");
113
114	print_set(&proto, 80);
115
116	memcpy(&check, &proto, sizeof (check));
117
118	if (select(maxfd + 1, sread, swrite, serr, &tv) == -1)
119		err(1, "select failed");
120
121	if (memcmp(&check, &proto, sizeof (check)) != 0) {
122		diff_sets(&check, &proto, sizeof (check));
123		warnx("fd set mismatch: check: %p  proto: %p", &check, &proto);
124		abort();
125	}
126
127	return (0);
128}
129