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/* t40c.c
*
* Test (pseudo) terminal devices
*
* Select works on regular files, (pseudo) terminal devices, streams-based
* files, FIFOs, pipes, and sockets. This test verifies selecting for (pseudo)
* terminal devices.
*
* This test is part of a bigger select test. It expects as argument which sub-
* test it is.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <sys/syslimits.h>
#include <errno.h>
#include <sys/wait.h>
#include <string.h>
#include "common.h"
#define TERMINALW "/dev/ttypf"
#define TERMINALR "/dev/ptypf"
#define SENDSTRING "minixrocks"
#define MAX_ERROR 5
static void open_terminal(int *child_fd, int *parent_fd) {
int fd1, fd2, i;
char opentermw[5+OPEN_MAX+1];
char opentermr[5+OPEN_MAX+1];
char *term[] = {"f","e","d","c","b","a","9","8","7","6","5","4","3","2","1"};
#define TERMS (sizeof(term)/sizeof(term[0]))
if (!child_fd || !parent_fd) exit(EXIT_FAILURE);
for (i = 0; i < TERMS; i++) {
snprintf(opentermw, 5+OPEN_MAX, "/dev/ttyp%s", term[i]);
snprintf(opentermr, 5+OPEN_MAX, "/dev/ptyp%s", term[i]);
/* Open master terminal for writing */
if((fd1 = open(opentermw, O_WRONLY)) == -1) continue;
/* Open slave terminal for reading */
if((fd2 = open(opentermr, O_RDONLY)) == -1) {
close(fd1);
continue;
}
*child_fd = fd1;
*parent_fd = fd2;
return;
}
/* If we get here we failed to find a terminal pair */
exit(EXIT_FAILURE);
}
static int do_child(int terminal) {
/* Going to sleep for two seconds to allow the parent proc to get ready */
sleep(2);
/* Try to write. Doesn't matter how many bytes we actually send. */
(void) write(terminal, SENDSTRING, strlen(SENDSTRING));
/* Wait for another second to allow the parent to process incoming data */
sleep(1);
/* Write some more, and wait some more. */
(void) write(terminal, SENDSTRING, strlen(SENDSTRING));
sleep(1);
close(terminal);
exit(0);
}
static int do_parent(int child, int terminal) {
fd_set fds_read, fds_read2, fds_write, fds_error;
int retval, terminal2, highest;
char buf[256];
/* Clear bit masks */
FD_ZERO(&fds_read); FD_ZERO(&fds_write); FD_ZERO(&fds_error);
/* Set read bits */
FD_SET(terminal, &fds_read);
FD_SET(terminal, &fds_write);
/* Test if we can read or write from/to fd. As fd is opened read only we
* cannot actually write, so the select should return immediately with fd
* set in fds_write, but not in fds_read. Note that the child waits two
* seconds before sending data. This gives us the opportunity run this
* sub-test as reading from fd is blocking at this point. */
retval = select(terminal+1, &fds_read, &fds_write, &fds_error, NULL);
if(retval != 1) em(1, "incorrect amount of ready file descriptors");
if(FD_ISSET(terminal, &fds_read)) em(2, "read should NOT be set");
if(!FD_ISSET(terminal, &fds_write)) em(3, "write should be set");
if(FD_ISSET(terminal, &fds_error)) em(4, "error should NOT be set");
/* Block until ready; until child wrote stuff */
FD_ZERO(&fds_read); FD_ZERO(&fds_write); FD_ZERO(&fds_error);
FD_SET(terminal, &fds_read);
retval = select(terminal+1, &fds_read, NULL, &fds_error, NULL);
if(retval != 1) em(5, "incorrect amount of ready file descriptors");
if(!FD_ISSET(terminal, &fds_read)) em(6, "read should be set");
if(FD_ISSET(terminal, &fds_error)) em(7, "error should not be set");
FD_ZERO(&fds_read); FD_ZERO(&fds_error);
FD_SET(terminal, &fds_write);
retval = select(terminal+1, NULL, &fds_write, NULL, NULL);
/* As it is impossible to write to a read only fd, this select should return
* immediately with fd set in fds_write. */
if(retval != 1) em(8, "incorrect amount or ready file descriptors");
/* See if selecting on the same object with two different fds results in both
* fds being returned as ready, immediately.
*/
terminal2 = dup(terminal);
if (terminal2 < 0) em(9, "unable to dup file descriptor");
FD_ZERO(&fds_read);
FD_SET(terminal, &fds_read);
FD_SET(terminal2, &fds_read);
fds_read2 = fds_read;
highest = terminal > terminal2 ? terminal : terminal2;
retval = select(highest+1, &fds_read, NULL, NULL, NULL);
if (retval != 2) em(10, "incorrect amount of ready file descriptors");
if (!FD_ISSET(terminal, &fds_read)) em(11, "first fd missing from set");
if (!FD_ISSET(terminal2, &fds_read)) em(12, "second fd missing from set");
/* Empty the buffer. */
if (read(terminal, buf, sizeof(buf)) <= 0) em(13, "unable to read data");
/* Repeat the test, now with a delay. */
retval = select(highest+1, &fds_read2, NULL, NULL, NULL);
if (retval != 2) em(10, "incorrect amount of ready file descriptors");
if (!FD_ISSET(terminal, &fds_read2)) em(11, "first fd missing from set");
if (!FD_ISSET(terminal2, &fds_read2)) em(12, "second fd missing from set");
close(terminal2);
close(terminal);
waitpid(child, &retval, 0);
exit(errct);
}
int main(int argc, char **argv) {
int forkres;
int master, slave;
/* Get subtest number */
if(argc != 2) {
printf("Usage: %s subtest_no\n", argv[0]);
exit(-1);
} else if(sscanf(argv[1], "%d", &subtest) != 1) {
printf("Usage: %s subtest_no\n", argv[0]);
exit(-1);
}
open_terminal(&master, &slave);
forkres = fork();
if(forkres == 0) do_child(master);
else if(forkres > 0) do_parent(forkres, slave);
else { /* Fork failed */
perror("Unable to fork");
exit(-1);
}
exit(-2); /* We're not supposed to get here. Both do_* routines should exit*/
}
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