Unix domain sockets are buggy

[tsmith201604]

Poll doesn't return the correct bits and ioctl stops working when one end of the socket is closed and the other end is open with incoming data still in the buffer. The expected results and the results I am getting are in the comments in the code below.

define _GNU_SOURCE

include <poll.h>

include <sys/ioctl.h>

include <sys/types.h>

include <sys/socket.h>

include <errno.h>

include <stdio.h>

include <unistd.h>

ifndef POLLRDHUP

define POLLRDHUP 0

endif

/*

Output under Linux:

POLL: 1 2011 (hup:10,rdhup:2000,in:1,err:0,rdnorm:0)
IOCTL 0 5
GOT BYTES: size=5 value='test'

Output under windows 10:
POLL: 1 11 (hup:10,rdhup:0,in:1,err:0,rdnorm:0)
IOCTL 0 0
GOT BYTES: size=5 value='test'

*/

int main(void)
{
int err;
int sv[2];
char buf[5] = { 0 };
struct pollfd pfd;
int n;
socketpair(AF_UNIX, SOCK_STREAM, 0, sv);
write(sv[1], "test", 5);
close(sv[1]);

pfd.fd = sv[0];
pfd.events = POLLIN | POLLRDHUP;
pfd.revents = 0;
err = poll(&pfd, 1, -1);
printf("POLL: %d %hx (hup:%x,rdhup:%x,in:%x,err:%x,rdnorm:%x)\n",
err,
pfd.revents,
pfd.revents & POLLHUP,
pfd.revents & POLLRDHUP,
pfd.revents & POLLIN,
pfd.revents & POLLERR,
pfd.revents & POLLRDNORM);
err = ioctl(pfd.fd, FIONREAD, &n);
printf("IOCTL %d %d\n", err, n);

err = read(pfd.fd, buf, 5);
if ( err == 0 )
{
printf("Unexpected EOF\n");
return 1;
} else if ( err < 0 )
{
perror("read");
return 1;
}
printf("GOT BYTES: size=%d value='%s'\n", err, buf);

return 0;

}

[patryk9200]

Known issue. Related to: #134

[benhillis]

Closing this out as a duplicate of #134.