test/select/test03.c

   1 /*
   2  * Test name: test02.c
   3  *
   4  * Objetive: The purpose of this test is to make sure that select works
   5  * when working with files.
   6  *
   7  * Description: This test shows more cases than in test02.c, where every
   8  * descriptor is ready. Here in one select call only half of the fd's will
   9  * be ready and in the next one none of them will be ready.
  10  *
  11  * Jose M. Gomez
  12  */
  13
  14 #include <sys/types.h>
  15 #include <fcntl.h>
  16 #include <unistd.h>
  17 #include <sys/select.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <limits.h>
  21 #include <sys/time.h>
  22
  23 void dump_fdset(fd_set *set) {
  24         int i;
  25         for (i = 0; i < OPEN_MAX; i++)
  26         if (FD_ISSET(i, set))
  27                 printf(" %d ", i);
  28         printf("\n");
  29 }
  30
  31 void main(void) {
  32         int fd1, fd2, fd3, fd4, fd5, fd6;       /* file descriptors of files */
  33         fd_set fds_read, fds_write;             /* bit maps */
  34         struct timeval timeout;                 /* timeout */
  35         int retval;                             /* ret value */
  36
  37         /* Creates the dummy files with different modes */
  38         fd1 = open("dummy1.txt", O_CREAT | O_RDONLY);
  39         if (fd1 < 0) {
  40                 perror("Error opening file");
  41                 exit(-1);
  42         }
  43
  44         fd2 = open("dummy2.txt", O_CREAT | O_RDONLY);
  45         if (fd2 < 0) {
  46                 perror("Error opening file");
  47                 exit(-1);
  48         }
  49
  50         fd3 = open("dummy3.txt", O_CREAT | O_WRONLY);
  51         if (fd3 < 0) {
  52                 perror("Error opening file");
  53                 exit(-1);
  54         }
  55
  56         fd4 = open("dummy4.txt", O_CREAT | O_WRONLY);
  57         if (fd4 < 0) {
  58                 perror("Error opening file");
  59                 exit(-1);
  60         }
  61
  62         fd5 = open("dummy5.txt", O_CREAT | O_RDWR);
  63         if (fd5 < 0) {
  64                 perror("Error opening file");
  65                 exit(-1);
  66         }
  67
  68         fd6 = open("dummy6.txt", O_CREAT | O_RDWR);
  69         if (fd6 < 0) {
  70                 perror("Error opening file");
  71                 exit(-1);
  72         }
  73
  74         /* Create the fd_set structures */
  75         FD_ZERO(&fds_read);
  76         FD_ZERO(&fds_write);
  77         FD_SET(fd1, &fds_write);        /* fd1 => O_RDONLY */
  78         FD_SET(fd2, &fds_write);        /* fd2 => O_RDONLY */
  79         FD_SET(fd3, &fds_read);         /* fd3 => O_WRONLY */
  80         FD_SET(fd4, &fds_read);         /* fd4 => O_WRONLY */
  81         FD_SET(fd5, &fds_read);         /* fd5 => O_RDWR */
  82         FD_SET(fd5, &fds_write);        /* fd5 => O_RDWR */
  83         FD_SET(fd6, &fds_read);         /* fd6 => O_RDWR */
  84         FD_SET(fd6, &fds_write);        /* fd6 => O_RDWR */
  85
  86         printf("* Dump INPUT fds_read:\n");
  87         dump_fdset(&fds_read);
  88         printf("* Dump INPUT fds_write:\n");
  89         dump_fdset(&fds_write);
  90
  91         retval=select(9, &fds_read, &fds_write, NULL, NULL);
  92         printf("\n***********************\n");
  93         printf("After select: \n");
  94         printf("Return value: %d\n", retval);
  95         printf("* Dump RESULTING fds_read:\n");
  96         dump_fdset(&fds_read);
  97         printf("* Dump RESULTING fds_write:\n");
  98         dump_fdset(&fds_write);
  99
 100         /* make a select call where none of them are ready (don't use fd5 and fd6) */
 101
 102         FD_ZERO(&fds_read);
 103         FD_ZERO(&fds_write);
 104         FD_SET(fd1, &fds_write);        /* fd1 => O_RDONLY */
 105         FD_SET(fd2, &fds_write);        /* fd2 => O_RDONLY */
 106         FD_SET(fd3, &fds_read);         /* fd3 => O_WRONLY */
 107         FD_SET(fd4, &fds_read);         /* fd4 => O_WRONLY */
 108
 109         /* make a select call where none of them are ready (don't use fd5 and fd6) */
 110         /* create a timeout as well */
 111         timeout.tv_sec = 5;
 112         timeout.tv_usec = 0;
 113         retval=select(7, &fds_read, &fds_write, NULL, NULL);
 114         printf("\n***********************\n");
 115         printf("After select: \n");
 116         printf("Return value: %d\n", retval);
 117         printf("* Dump RESULTING fds_read:\n");
 118         dump_fdset(&fds_read);
 119         printf("* Dump RESULTING fds_write:\n");
 120         dump_fdset(&fds_write);
 121
 122         /* close and delete dummy files */
 123         close(fd1);
 124         close(fd2);
 125         close(fd3);
 126         close(fd4);
 127         close(fd5);
 128         close(fd6);
 129         unlink("dummy1.txt");
 130         unlink("dummy2.txt");
 131         unlink("dummy3.txt");
 132         unlink("dummy4.txt");
 133         unlink("dummy5.txt");
 134         unlink("dummy6.txt");
 135 }