2007-01-03 Paolo Bonzini <bonzini@gnu.org>

	    Yoann Vandoorselaere <yoann.v@prelude-ids.com>

	* lib/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).

diff --git a/ChangeLog b/ChangeLog
index 4efeed4..87ccd6f 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2007-01-03  Paolo Bonzini  <bonzini@gnu.org>
+           Yoann Vandoorselaere <yoann.v@prelude-ids.com>
+
+       * lib/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).
+
 2007-01-01  Bruno Haible  <bruno@clisp.org>
 
        * modules/lchmod (Include): Require lchmod.h, not lchown.h.

diff --git a/lib/poll.c b/lib/poll.c
index 78af62d..cda022c 100644 (file)
--- a/lib/poll.c
+++ b/lib/poll.c
@@ -1,7 +1,7 @@
 /* Emulation for poll(2)
    Contributed by Paolo Bonzini.
 
-   Copyright 2001, 2002, 2003, 2006 Free Software Foundation, Inc.
+   Copyright 2001, 2002, 2003, 2006, 2007 Free Software Foundation, Inc.
 
    This file is part of gnulib.
 
@@ -63,7 +63,7 @@ poll (pfd, nfd, timeout)
 {
   fd_set rfds, wfds, efds;
   struct timeval tv, *ptv;
-  int maxfd, rc, happened;
+  int maxfd, rc;
   nfds_t i;
 
 #ifdef _SC_OPEN_MAX
@@ -143,67 +143,62 @@ poll (pfd, nfd, timeout)
 
   /* 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;
-         if (FD_ISSET (pfd[i].fd, &rfds))
-           {
-             int r;
-             long avail = -1;
-             /* support for POLLHUP.  */
+  rc = 0;
+  for (i = 0; i < nfd; i++)
+    if (pfd[i].fd < 0)
+      pfd[i].revents = 0;
+    else
+      {
+       int happened = 0, sought = pfd[i].events;
+       if (FD_ISSET (pfd[i].fd, &rfds))
+         {
+           int r;
+           
 #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;
+           char data[64];
+           r = recv (pfd[i].fd, data, sizeof (data), MSG_PEEK);
 #endif
-
-             /* 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;
-           }
-
-         if (FD_ISSET (pfd[i].fd, &wfds))
-           happened |= POLLOUT | POLLWRNORM | POLLWRBAND;
-
-         if (FD_ISSET (pfd[i].fd, &efds))
-           happened |= POLLPRI | POLLRDBAND;
-
-         pfd[i].revents |= pfd[i].events & happened;
-         rc += (happened > 0);
-       }
-    }
+           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;
+           
+           else
+             happened |= POLLERR;
+         }
+       
+       if (FD_ISSET (pfd[i].fd, &wfds))
+         happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
+       
+       if (FD_ISSET (pfd[i].fd, &efds))
+         happened |= (POLLPRI | POLLRDBAND) & sought;
+       
+       if (happened)
+         {
+           pfd[i].revents = happened;
+           rc++;
+         }
+      }
 
   return rc;
 }