Re: PTY dies when master in parent process is closed.

[Takashi Yano <takashi dot yano at nifty dot ne dot jp>]

On Thu, 5 Mar 2015 14:58:39 +0100
Corinna Vinschen <corinna-cygwin@cygwin.com> wrote:

> I applied a patch.  Please have a look.

I have tested the latest CVS version, and found
a new problem.

With new CVS version, slave side can not detect
closure of master.

Please use following Test Case 3. Test Case 3 is
not terminated by itself with latest CVS.

It seems that the program is stopping at
cygwait(input_available_event, time_to_wait)
in fhandler_pty_slave::read().

I guess input_available_event should be set when
the last valid master fd is closed.


/***************/
/* Test Case 3 */
/***************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <pty.h>
#include <wait.h>

int main()
{
    int master, slave;
    pid_t pid;

    if ( openpty(&master, &slave, NULL, NULL, NULL) < 0) {
        perror("openpty()");
        exit(EXIT_FAILURE);
    }

    pid = fork();
    if (pid < 0) {
        perror("fork()");
        exit(EXIT_FAILURE);
    }

    if (pid != 0) { /* Parent */
        close(slave);
        write(master, "0123456789\n", 11);
        usleep(100000); /* wait for slave read() */
        close(master);
        wait(NULL);
    } else { /* Child */
        close(master);
        for (;;) {
            char buf[BUFSIZ];
            int len = read(slave, buf, sizeof(buf));
            if (len <= 0) {
                perror("read()");
                break;
            }
            write(STDOUT_FILENO, buf, len);
        }
        close(slave);
    }

    return EXIT_SUCCESS;
}


-- 
Takashi Yano <takashi.yano@nifty.ne.jp>

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