* poll.cc: Allow any descriptor and any number of descriptors.

        Allocate fd_set struct sdynamically.

1 files changed, 34 insertions, 20 deletions

diff --git a/winsup/cygwin/poll.cc b/winsup/cygwin/poll.cc
index 2e28516..b0a5ebd 100644
--- a/winsup/cygwin/poll.cc
+++ b/winsup/cygwin/poll.cc
@@ -8,44 +8,58 @@
    Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
    details. */
 
-#include "winsup.h"
 #include <sys/poll.h>
+#include <errno.h>
+#include "winsup.h"
 
 extern "C"
 int
 poll (struct pollfd *fds, unsigned int nfds, int timeout)
 {
   int max_fd = 0;
-  fd_set open_fds, read_fds, write_fds, except_fds;
+  fd_set *open_fds, *read_fds, *write_fds, *except_fds;
   struct timeval tv = { timeout / 1000, (timeout % 1000) * 1000 };
 
-  FD_ZERO (&open_fds);
-  FD_ZERO (&read_fds);
-  FD_ZERO (&write_fds);
-  FD_ZERO (&except_fds);
+  for (unsigned int i = 0; i < nfds; ++i)
+    if (fds[i].fd > max_fd)
+      max_fd = fds[i].fd;
+
+  size_t fds_size = howmany(max_fd + 1, NFDBITS) * sizeof (fd_mask);
+
+  open_fds = (fd_set *) alloca (fds_size);
+  read_fds = (fd_set *) alloca (fds_size);
+  write_fds = (fd_set *) alloca (fds_size);
+  except_fds = (fd_set *) alloca (fds_size);
+
+  if (!open_fds || !read_fds || !write_fds || !except_fds)
+    {
+      set_errno (ENOMEM);
+      return -1;
+    }
+
+  memset (open_fds, 0, fds_size);
+  memset (read_fds, 0, fds_size);
+  memset (write_fds, 0, fds_size);
+  memset (except_fds, 0, fds_size);
 
   for (unsigned int i = 0; i < nfds; ++i)
-    if (fds[i].fd < FD_SETSIZE
-        && !dtable.not_open (fds[i].fd))
+    if (!dtable.not_open (fds[i].fd))
       {
-        FD_SET (fds[i].fd, &open_fds);
+        FD_SET (fds[i].fd, open_fds);
         if (fds[i].events & POLLIN)
-          FD_SET (fds[i].fd, &read_fds);
+          FD_SET (fds[i].fd, read_fds);
         if (fds[i].events & POLLOUT)
-          FD_SET (fds[i].fd, &write_fds);
+          FD_SET (fds[i].fd, write_fds);
         if (fds[i].events & POLLPRI)
-          FD_SET (fds[i].fd, &except_fds);
-        if (fds[i].fd > max_fd)
-          max_fd = fds[i].fd;
+          FD_SET (fds[i].fd, except_fds);
       }
 
-  int ret = cygwin_select (max_fd + 1, &read_fds, &write_fds, &except_fds,
+  int ret = cygwin_select (max_fd + 1, read_fds, write_fds, except_fds,
                            timeout < 0 ? NULL : &tv);
 
   for (unsigned int i = 0; i < nfds; ++i)
     {
-      if (fds[i].fd >= FD_SETSIZE
-          || !FD_ISSET (fds[i].fd, &open_fds))
+      if (!FD_ISSET (fds[i].fd, open_fds))
         fds[i].revents = POLLNVAL;
       else if (dtable.not_open(fds[i].fd))
         fds[i].revents = POLLHUP;
@@ -54,11 +68,11 @@ poll (struct pollfd *fds, unsigned int nfds, int timeout)
       else
         {
           fds[i].revents = 0;
-          if (FD_ISSET (fds[i].fd, &read_fds))
+          if (FD_ISSET (fds[i].fd, read_fds))
             fds[i].revents |= POLLIN;
-          if (FD_ISSET (fds[i].fd, &write_fds))
+          if (FD_ISSET (fds[i].fd, write_fds))
             fds[i].revents |= POLLOUT;
-          if (FD_ISSET (fds[i].fd, &except_fds))
+          if (FD_ISSET (fds[i].fd, except_fds))
             fds[i].revents |= POLLPRI;
         }
     }