Correctly handle the case when select runs out of filehandles.

2 files changed, 14 insertions, 5 deletions

diff --git a/examples/df.c b/examples/df.c
index 91c07d7d..eed31a34 100644
--- a/examples/df.c
+++ b/examples/df.c
@@ -15,14 +15,13 @@ main (int argc, char *argv[])
     exit (1);
   }
 
-  g = guestfs_create ();
-  if (!g) exit (1);
+  if (!(g = guestfs_create ())) exit (1);
 
   guestfs_set_verbose (g, 1);
-  guestfs_add_drive (g, argv[1]);
+  if (guestfs_add_drive (g, argv[1]) == -1) exit (1);
 
-  guestfs_launch (g);
-  guestfs_wait_ready (g);
+  if (guestfs_launch (g) == -1) exit (1);
+  if (guestfs_wait_ready (g) == -1) exit (1);
 
 
 
diff --git a/src/guestfs.c b/src/guestfs.c
index 7e883035..ea86f1ba 100644
--- a/src/guestfs.c
+++ b/src/guestfs.c
@@ -899,6 +899,7 @@ static fd_set wset;
 static fd_set xset;
 static int select_init_done = 0;
 static int max_fd = -1;
+static int nr_fds = 0;
 static struct handle_cb_data *handle_cb_data = NULL;
 
 static void
@@ -962,6 +963,8 @@ select_add_handle (guestfs_h *g, int fd, int events,
   handle_cb_data[fd].cb = cb;
   handle_cb_data[fd].data = data;
 
+  nr_fds++;
+
   /* Any integer >= 0 can be the handle, and this is as good as any ... */
   return fd;
 }
@@ -991,6 +994,8 @@ select_remove_handle (guestfs_h *g, int fd)
 				   sizeof (struct handle_cb_data) * (max_fd+1));
   }
 
+  nr_fds--;
+
   return 0;
 }
 
@@ -1024,6 +1029,11 @@ select_main_loop_run (guestfs_h *g)
 
   old_level = level++;
   while (level > old_level) {
+    if (nr_fds == 0) {
+      level = old_level;
+      break;
+    }
+
     rset2 = rset;
     wset2 = wset;
     xset2 = xset;