Fix Bug#22814

* lisp/autorevert.el (global-auto-revert-mode): Do not set
`auto-revert-use-notify' to nil.

* etc/NEWS: Mention this.

* etc/PROBLEMS: Remove problem Bug#22814.

* src/kqueue.c: Include <sys/resource.h>.
(Fkqueue_add_watch): Limit the number of used file descriptors.
(Bug#22814)

* test/lisp/filenotify-tests.el (file-notify--test-remote-enabled)
(file-notify-test00-availability, file-notify-test01-add-watch)
(file-notify-test02-events, file-notify-test06-many-events):
Use #' read syntax for functions.
(file-notify-test05-dir-validity)
(file-notify-test06-many-events): Simplify directory creation.
(file-notify-test09-sufficient-ressources): New test.

1 files changed, 23 insertions, 1 deletions

diff --git a/src/kqueue.c b/src/kqueue.c
index a69d06da3ae..7e3bfdd5746 100644
--- a/src/kqueue.c
+++ b/src/kqueue.c
@@ -29,6 +29,10 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "keyboard.h"
 #include "process.h"
 
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif /* HAVE_SYS_RESOURCE_H  */
+
 
 /* File handle for kqueue.  */
 static int kqueuefd = -1;
@@ -368,9 +372,12 @@ only when the upper directory of the renamed file is watched.  */)
   (Lisp_Object file, Lisp_Object flags, Lisp_Object callback)
 {
   Lisp_Object watch_object, dir_list;
-  int fd, oflags;
+  int maxfd, fd, oflags;
   u_short fflags = 0;
   struct kevent kev;
+#ifdef HAVE_GETRLIMIT
+  struct rlimit rlim;
+#endif /* HAVE_GETRLIMIT  */
 
   /* Check parameters.  */
   CHECK_STRING (file);
@@ -383,6 +390,21 @@ only when the upper directory of the renamed file is watched.  */)
   if (! FUNCTIONP (callback))
     wrong_type_argument (Qinvalid_function, callback);
 
+  /* Check available file descriptors.  */
+#ifdef HAVE_GETRLIMIT
+  if (! getrlimit (RLIMIT_NOFILE, &rlim))
+    maxfd = rlim.rlim_cur;
+  else
+#endif /* HAVE_GETRLIMIT  */
+    maxfd = 256;
+
+  /* We assume 50 file descriptors are sufficient for the rest of Emacs.  */
+  if ((maxfd - 50) < XINT (Flength (watch_list)))
+    xsignal2
+      (Qfile_notify_error,
+       build_string ("File watching not possible, no file descriptor left"),
+       Flength (watch_list));
+
   if (kqueuefd < 0)
     {
       /* Create kqueue descriptor.  */