The previous patch had an issue. Here is an updated version.
Ok, here is what I'm going to commit. I simplified a bit the logic to
not using ioctl on hosts other than Mac OS X.
The patch is -b to simplify reading it.
Thanks,
Paolo
2007-01-03 Paolo Bonzini <[EMAIL PROTECTED]>
Yoann Vandoorselaere <[EMAIL PROTECTED]>
* poll.c (poll): Use recv on Mac OS X to distinguish connected
sockets, server sockets, and other file descriptors. Count errors
to compute the return value. Reorder the code a bit to be easier
to follow. Don't set event bits that were not requested (except
POLLERR and POLLHUP).
Index: poll.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/poll.c,v
retrieving revision 1.5
diff -u -b -r1.5 poll.c
--- poll.c 28 Sep 2006 19:58:33 -0000 1.5
+++ poll.c 3 Jan 2007 10:46:09 -0000
@@ -63,7 +63,7 @@
{
fd_set rfds, wfds, efds;
struct timeval tv, *ptv;
- int maxfd, rc, happened;
+ int maxfd, rc;
nfds_t i;
#ifdef _SC_OPEN_MAX
@@ -143,65 +143,60 @@
/* examine fd sets */
rc = select (maxfd + 1, &rfds, &wfds, &efds, ptv);
+ if (rc < 0)
+ return rc;
/* establish results */
- if (rc > 0)
- {
rc = 0;
for (i = 0; i < nfd; i++)
- {
- pfd[i].revents = 0;
if (pfd[i].fd < 0)
- continue;
-
- happened = 0;
+ pfd[i].revents = 0;
+ else
+ {
+ int happened = 0, sought = pfd[i].events;
if (FD_ISSET (pfd[i].fd, &rfds))
{
int r;
- long avail = -1;
- /* support for POLLHUP. */
+
#if defined __MACH__ && defined __APPLE__
- /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
for
- some kinds of descriptors. Use FIONREAD to emulate POLLHUP.
- It is still not completely POSIX compliant (it does not fully
- work on TTYs), but at least it does not delete data! For other
- platforms, we still use MSG_PEEK because it was proved to be
- reliable, and I a leery of changing it. */
- do
- r = ioctl (pfd[i].fd, FIONREAD, &avail);
- while (r == -1 && (errno == EAGAIN || errno == EINTR));
- if (avail < 0)
- avail = 0;
+ /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
+ for some kinds of descriptors. Detect if this descriptor is a
+ connected socket, a server socket, or something else using a
+ 0-byte recv, and use ioctl(2) to detect POLLHUP. */
+ r = recv (pfd[i].fd, NULL, 0, MSG_PEEK);
+ if (r == 0 || errno == ENOTSOCK)
+ ioctl(pfd[i].fd, FIONREAD, &r);
#else
char data[64];
- r = recv (pfd[i].fd, data, 64, MSG_PEEK);
- if (r == -1)
- {
- avail = (errno == ESHUTDOWN || errno == ECONNRESET ||
- errno == ECONNABORTED || errno == ENETRESET) ? 0 :
-1;
- errno = 0;
- }
- else
- avail = r;
+ r = recv (pfd[i].fd, data, sizeof (data), MSG_PEEK);
#endif
+ if (r == 0)
+ happened |= POLLHUP;
+
+ /* If the event happened on an unconnected server socket,
+ that's fine. */
+ else if (r > 0 || ( /* (r == -1) && */ errno == ENOTCONN))
+ happened |= (POLLIN | POLLRDNORM) & sought;
+
+ /* Distinguish hung-up sockets from other errors. */
+ else if (errno == ESHUTDOWN || errno == ECONNRESET
+ || errno == ECONNABORTED || errno == ENETRESET)
+ happened |= POLLHUP;
- /* An hung up descriptor does not increase the return value! */
- if (avail == 0)
- pfd[i].revents |= POLLHUP;
- else if (avail == -1)
- pfd[i].revents |= POLLERR;
else
- happened |= POLLIN | POLLRDNORM;
+ happened |= POLLERR;
}
if (FD_ISSET (pfd[i].fd, &wfds))
- happened |= POLLOUT | POLLWRNORM | POLLWRBAND;
+ happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
if (FD_ISSET (pfd[i].fd, &efds))
- happened |= POLLPRI | POLLRDBAND;
+ happened |= (POLLPRI | POLLRDBAND) & sought;
- pfd[i].revents |= pfd[i].events & happened;
- rc += (happened > 0);
+ if (happened)
+ {
+ pfd[i].revents = happened;
+ rc++;
}
}
