usr/src/test/libc-tests/tests/select/select_test.c

   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
  27 void
  28 diff_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
  37 void
  38 print_set(fd_set *a, size_t size)
  39 {
  40         for (int i = 0; i < size; i++) {
  41                 if (FD_ISSET(i, a))
  42                         putc('1', stdout);
  43                 else
  44                         putc('0', stdout);
  45         }
  46
  47         putc('\n', stdout);
  48 }
  49
  50 int
  51 main(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         read(null, &buf, 1);
  89         read(null, &buf, 1);
  90
  91         if ((zero = open("/dev/zero", O_RDWR)) == -1)
  92                 err(1, "couldn't open /dev/zero");
  93
  94         for (int i = zero; i < (zero + nfds); i++) {
  95                 int fd = (serr != NULL) ? null : zero;
  96                 if (arc4random_uniform(100) > 90) {
  97                         FD_SET(i, &proto);
  98                 }
  99
 100                 if (dup2(fd, i) == -1)
 101                         err(1, "couldn't dup fd to fd %d", i);
 102                 maxfd = i;
 103         }
 104
 105         if (swrite != NULL)
 106                 puts("write");
 107         else if (sread != NULL)
 108                 puts("read");
 109         else if (serr != NULL)
 110                 puts("err");
 111
 112         print_set(&proto, 80);
 113
 114         memcpy(&check, &proto, sizeof (check));
 115
 116         if (select(maxfd + 1, sread, swrite, serr, &tv) == -1)
 117                 err(1, "select failed");
 118
 119         if (memcmp(&check, &proto, sizeof (check)) != 0) {
 120                 diff_sets(&check, &proto, sizeof (check));
 121                 warnx("fd set mismatch: check: %p  proto: %p", &check, &proto);
 122                 abort();
 123         }
 124
 125         return (0);
 126 }