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