minix/tests/t40g.c

   1 /* t40g.c
   2  *
   3  * Test select on character driver that does not support select
   4  *
   5  * We use /dev/zero for this right now.  If the memory driver ever implements
   6  * select support, this test should be changed to use another character driver.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <unistd.h>
  12 #include <sys/types.h>
  13 #include <sys/select.h>
  14 #include <sys/wait.h>
  15 #include <sys/time.h>
  16 #include <time.h>
  17 #include <errno.h>
  18 #include <string.h>
  19 #include <signal.h>
  20 #include <fcntl.h>
  21
  22 #include "common.h"
  23
  24 int
  25 main(int argc, char **argv)
  26 {
  27         fd_set set;
  28         int fd, retval;
  29
  30         /* Get subtest number */
  31         if (argc != 2 || sscanf(argv[1], "%d", &subtest) != 1) {
  32                 printf("Usage: %s subtest_no\n", argv[0]);
  33                 exit(-2);
  34         }
  35
  36         /*
  37          * Do a select on /dev/zero, with the expectation that it will fail
  38          * with an EBADF error code.
  39          */
  40         fd = open("/dev/zero", O_RDONLY);
  41         if (fd < 0) em(1, "unable to open /dev/zero");
  42
  43         FD_ZERO(&set);
  44         FD_SET(fd, &set);
  45
  46         retval = select(fd + 1, &set, NULL, NULL, NULL);
  47         if (retval != -1) em(2, "select call was expected to fail");
  48         if (errno != EBADF) em(3, "error code other than EBADF returned");
  49         if (!FD_ISSET(fd, &set)) em(4, "file descriptor set was modified");
  50
  51         exit(errct);
  52 }