wine/server sock.c

[Martin Wilck]

Am Die, 2002-06-25 um 19.09 schrieb Alexandre Julliard:

> The regression test was failing because the client didn't receive the
> FD_CLOSE notification. With the fix it now works both in 2.2 and 2.4
> kernels.

OK - but I am not sure if the second change can't break something for
2.4 or other POSIX systems - here POLLHUP would IMO mean that the peer
has closed both sides of the connection, justifying to reset FD_WRITE
and FD_WINE_CONNECTED just as we do with POLLERR. Perhaps we should
carry out a small test at wineserver startup to determine whether a
shutdown() can cause a POLLHUP to be received (below a small
proof-of-concept test program that shows how that could work - I tested
it on 2.2 and 2.4, it yields the expected results).

I have another issue that I am not sure how to fix yet: For UDP sockets,
it is perfectly legal to receive 0 bytes, thus an empty receive should
not be interpreted as a hangup.
I think this requires that we store the socket type (STREAM or DGRAM) 
in the server socket structure and test for empty receives only for
DGRAM sockets.

Regards,
Martin

PS I'd be grateful if you could also help me out with that GUID
   question...

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/poll.h>
#include <sys/socket.h>

typedef enum {
    SOCK_SHUTDOWN_ERROR = -1,
    SOCK_SHUTDOWN_EOF = 0,
    SOCK_SHUTDOWN_POLLHUP = 1
} sock_shutdown_t;

static sock_shutdown_t sock_shutdown_pollhup = SOCK_SHUTDOWN_ERROR;

static sock_shutdown_t sock_check_pollhup (void)
{
    sock_shutdown_t ret = SOCK_SHUTDOWN_ERROR;
    int fd[2], n;
    struct pollfd pfd;
    char dummy;

    if ( socketpair ( AF_UNIX, SOCK_STREAM, 0, fd ) ) goto out;
    if ( shutdown ( fd[0], 1 ) ) goto out;
    
    pfd.fd = fd[1];
    pfd.events = POLLIN;
    pfd.revents = 0;
    
    n = poll ( &pfd, 1, 0 );
    if ( n != 1 ) goto out; /* error or timeout */
    if ( pfd.revents & POLLHUP ) 
        ret = SOCK_SHUTDOWN_POLLHUP;
    else if ( pfd.revents & POLLIN &&
              read ( fd[1], &dummy, 1 ) == 0 )
        ret = SOCK_SHUTDOWN_EOF;

out:
    close ( fd[0] );
    close ( fd[1] );
    return ret;
}

int main (void)
{
    sock_shutdown_pollhup = sock_check_pollhup ();
    switch ( sock_shutdown_pollhup )
    {
    case SOCK_SHUTDOWN_EOF:
        printf ( "shutdown() causes EOF\n" );
        break;
    case SOCK_SHUTDOWN_POLLHUP:
        printf ( "shutdown() causes POLLHUP\n" );
        break;
    default:
        printf ( "ERROR in sock_check_pollhup()\n" );
        return 257;
    }
    return 0;
}


-- 
Martin Wilck                Phone: +49 5251 8 15113
Fujitsu Siemens Computers   Fax:   +49 5251 8 20409
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