Release unused filedescriptors in the privileged X server process.

There is no reason to keep /dev/pci* and /dev/ttyC* open in this process.
pointed to  by deraadt. ok kettenis@ deraadt@

xserver/hw/kdrive/ephyr/ephyrinit.c

@@ -375,6 +375,13 @@ OsVendorInit(void)
     }
 }
 
+#ifdef X_PRIVSEP
+void
+priv_vendor_init(void)
+{
+}
+#endif
+
 KdCardFuncs ephyrFuncs = {
     ephyrCardInit,              /* cardinit */
     ephyrScreenInitialize,      /* scrinit */

xserver/hw/vfb/InitOutput.c

@@ -219,6 +219,13 @@ OsVendorInit(void)
 {
 }
 
+#ifdef X_PRIVSEP
+void
+priv_vendor_init(void)
+{
+}
+#endif
+
 void
 OsVendorFatalError(const char *f, va_list args)
 {

xserver/hw/xfree86/os-support/bsd/bsd_init.c

@@ -820,4 +820,15 @@ xf86DropPriv(void)
         }
     }
 }
+
+/*
+ * Called in the privileged child
+ */
+void
+priv_vendor_init(void)
+{
+	/* release resources it won't need */
+	pci_system_cleanup();
+	close(xf86Info.consoleFd);
+}
 #endif

xserver/hw/xnest/Init.c

@@ -156,6 +156,14 @@ OsVendorInit(void)
     return;
 }
 
+#ifdef X_PRIVSEP
+void
+priv_vendor_init(void)
+{
+    return;
+}
+#endif
+
 void
 OsVendorFatalError(const char *f, va_list args)
 {

xserver/include/os.h

@@ -314,6 +314,8 @@ extern _X_EXPORT int
 ChownLock(uid_t, gid_t);
 extern _X_EXPORT int
 priv_open_device(const char *);
+extern _X_EXPORT void
+priv_vendor_init(void);
 #endif
 
 extern _X_EXPORT int

xserver/os/privsep.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: privsep.c,v 1.31 2019/06/11 14:51:34 jcs Exp $ */
+/* $OpenBSD: privsep.c,v 1.32 2020/04/20 18:17:26 matthieu Exp $ */
 /*
  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
@@ -279,6 +279,7 @@ priv_init(uid_t uid, gid_t gid)
 		signal(i, SIG_DFL);
 	setproctitle("[priv]");
 	close(socks[1]);
+	priv_vendor_init();
 
 	for (dev = allowed_devices; dev->name != NULL; dev++) {
 		if (unveil(dev->name, "rw") == -1)