From: Po Lu <luangruo@yahoo.com>
Date: Thu, 22 Feb 2024 01:53:48 +0000 (+0800)
Subject: Enable inotify on systems with inotify_init yet no init1 variant
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=5a822ca3002e581544a1e59ce6b55246d6cbd790;p=emacs.git

Enable inotify on systems with inotify_init yet no init1 variant

* configure.ac (HAVE_INOTIFY): Check for the presence of
inotify_init in addition to inotify_init1.

* src/inotify.c (Finotify_add_watch): Implement with
inotify_init if inotify_init1 is absent.

(cherry picked from commit 39a84232700c40fa74305970dd16cd5cb8b8bea0)
---

diff --git a/configure.ac b/configure.ac
index b9bcb9a4648..f582d1331db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4121,16 +4121,16 @@ case $with_file_notification,$opsys in
     fi ;;
 esac
 
-dnl inotify is available only on GNU/Linux.
+dnl inotify is available only on Linux-kernel based systems.
 case $with_file_notification,$NOTIFY_OBJ in
   inotify, | yes,)
     AC_CHECK_HEADER([sys/inotify.h])
     if test "$ac_cv_header_sys_inotify_h" = yes ; then
-	AC_CHECK_FUNC([inotify_init1])
-	if test "$ac_cv_func_inotify_init1" = yes; then
+	AC_CHECK_FUNCS([inotify_init inotify_init1])
+	if test "$ac_cv_func_inotify_init" = yes; then
 	  AC_DEFINE([HAVE_INOTIFY], [1], [Define to 1 to use inotify.])
 	  NOTIFY_OBJ=inotify.o
-	  NOTIFY_SUMMARY="yes -lglibc (inotify)"
+	  NOTIFY_SUMMARY="yes (inotify)"
        fi
     fi ;;
 esac
diff --git a/src/inotify.c b/src/inotify.c
index 2ee874530cc..7140568f1b6 100644
--- a/src/inotify.c
+++ b/src/inotify.c
@@ -26,6 +26,8 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include "termhooks.h"
 
 #include <errno.h>
+#include <fcntl.h>
+
 #include <sys/inotify.h>
 #include <sys/ioctl.h>
 
@@ -434,7 +436,15 @@ IN_ONESHOT  */)
 
   if (inotifyfd < 0)
     {
+#ifdef HAVE_INOTIFY_INIT1
       inotifyfd = inotify_init1 (IN_NONBLOCK | IN_CLOEXEC);
+#else /* !HAVE_INOTIFY_INIT1 */
+      /* This is prey to race conditions with other threads calling
+	 exec.  */
+      inotifyfd = inotify_init ();
+      fcntl (inotifyfd, F_SETFL, O_NONBLOCK);
+      fcntl (inotifyfd, F_SETFD, O_CLOEXEC);
+#endif /* HAVE_INOTIFY_INIT1 */
       if (inotifyfd < 0)
 	report_file_notify_error ("File watching is not available", Qnil);
       watch_list = Qnil;