Mail Archives: cygwin/2002/01/01/10:07:39
On Mon, Dec 31, 2001 at 07:53:28PM +0100, Ralf Habacker wrote:
> > >- unix domain socket - The above mentioned os supports creating unix
> > >domain sockets with previous existing files. On cygwin the unix domain
> > >sockets couldn't be bound on existing files, so it has to be removed
> > >first.
> >
> > Sounds like a bug. Submit a patch.
It's not a bug, it's Linux compliant behaviour. Try the following
code on Linux and Cygwin:
================================== SNIP ==============================
#include <stdio.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
int
main(int argc, char **argv)
{
int sockfd;
socklen_t len;
struct sockaddr_un addr1, addr2;
if (argc != 2)
{
fprintf (stderr, "Idiot\n");
return 1;
}
sockfd = socket (AF_LOCAL, SOCK_STREAM, 0);
if (sockfd < 0)
{
fprintf (stderr, "socket: %d, %s\n", errno, strerror (errno));
return 1;
}
memset (&addr1, 0, sizeof addr1);
addr1.sun_family = AF_LOCAL;
strncpy (addr1.sun_path, argv[1], sizeof addr1.sun_path - 1);
if (bind (sockfd, (struct sockaddr *) &addr1, SUN_LEN (&addr1)) < 0)
{
fprintf (stderr, "bind: %d, %s\n", errno, strerror (errno));
return 1;
}
len = sizeof addr2;
if (getsockname (sockfd, (struct sockaddr *) &addr2, &len) < 0)
{
fprintf (stderr, "getsockname: %d, %s\n", errno, strerror (errno));
return 1;
}
printf ("bound name = %s, returned len = %d\n", addr2.sun_path, len);
return 0;
}
================================== SNAP ==============================
Linux:
------
$ gcc -o uds uds.c
$ ./uds /tmp/foo.bar
bound name = /tmp/foo.bar, returned len = 15
$ ./uds /tmp/foo.bar
bind: 98, Address already in use
Cygwin:
-------
$ gcc -o uds uds.c
$ ./uds /tmp/foo.bar
bound name = <some random string here>, returned len = 16
$ ./uds /tmp/foo.bar
bind: 112, Address already in use
That shows that Cygwin's getsockname() doesn't return a correct
sockname for unix domain sockets but the bind() call behaves
correct. An application that depends on (actually undocumented)
behaviour that a unix domain socket can be rebound is doing something
wrong.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Developer mailto:cygwin AT cygwin DOT com
Red Hat, Inc.
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