os/inputthread: Fix setting of cloexec on file descriptors

O_CLOEXEC is not a file bit.  It is not setable with F_SETFL.  One must
use it when calling open(2).  To set it cloexec on an existing fd,
F_SETFD and FD_CLOEXEC must be used.

This also fixes a build failure regression on configurations that don't
have O_CLOEXEC defined.

cf: http://pubs.opengroup.org/onlinepubs/9699919799/functions/fcntl.html
Regressed-in: 30ac7567980a1eb79d084a63e0e74e1d9a3af673

Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Reviewed-by: Julien Cristau <jcristau@debian.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/os/inputthread.c b/os/inputthread.c
index 1cd1c2af4..6b379f5ea 100644
--- a/os/inputthread.c
+++ b/os/inputthread.c
@@ -379,6 +379,7 @@ void
 InputThreadPreInit(void)
 {
     int fds[2], hotplugPipe[2];
+    int flags;
 
     if (!InputThreadEnable)
         return;
@@ -402,13 +403,23 @@ InputThreadPreInit(void)
      * in parallel.
      */
     inputThreadInfo->readPipe = fds[0];
-    fcntl(inputThreadInfo->readPipe, F_SETFL, O_NONBLOCK | O_CLOEXEC);
+    fcntl(inputThreadInfo->readPipe, F_SETFL, O_NONBLOCK);
+    flags = fcntl(inputThreadInfo->readPipe, F_GETFD);
+    if (flags != -1) {
+        flags |= FD_CLOEXEC;
+        (void)fcntl(inputThreadInfo->readPipe, F_SETFD, &flags);
+    }
     SetNotifyFd(inputThreadInfo->readPipe, InputThreadNotifyPipe, X_NOTIFY_READ, NULL);
 
     inputThreadInfo->writePipe = fds[1];
 
     hotplugPipeRead = hotplugPipe[0];
-    fcntl(hotplugPipeRead, F_SETFL, O_NONBLOCK | O_CLOEXEC);
+    fcntl(hotplugPipeRead, F_SETFL, O_NONBLOCK);
+    flags = fcntl(hotplugPipeRead, F_GETFD);
+    if (flags != -1) {
+        flags |= FD_CLOEXEC;
+        (void)fcntl(hotplugPipeRead, F_SETFD, &flags);
+    }
     hotplugPipeWrite = hotplugPipe[1];
 
 }