Imported Upstream version 1.4.15

gl/cloexec.c

@@ -1,6 +1,6 @@
 /* closexec.c - set or clear the close-on-exec descriptor flag
 
-   Copyright (C) 1991, 2004, 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 1991, 2004-2006, 2009-2010 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -21,21 +21,24 @@
 
 #include "cloexec.h"
 
-#include <unistd.h>
+#include <errno.h>
 #include <fcntl.h>
-
-#ifndef FD_CLOEXEC
-# define FD_CLOEXEC 1
-#endif
+#include <unistd.h>
 
 /* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
    or clear the flag if VALUE is false.
-   Return 0 on success, or -1 on error with `errno' set. */
+   Return 0 on success, or -1 on error with `errno' set.
+
+   Note that on MingW, this function does NOT protect DESC from being
+   inherited into spawned children.  Instead, either use dup_cloexec
+   followed by closing the original DESC, or use interfaces such as
+   open or pipe2 that accept flags like O_CLOEXEC to create DESC
+   non-inheritable in the first place.  */
 
 int
 set_cloexec_flag (int desc, bool value)
 {
-#if defined F_GETFD && defined F_SETFD
+#ifdef F_SETFD
 
   int flags = fcntl (desc, F_GETFD, 0);
 
@@ -44,15 +47,37 @@ set_cloexec_flag (int desc, bool value)
       int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
 
       if (flags == newflags
-	  || fcntl (desc, F_SETFD, newflags) != -1)
-	return 0;
+          || fcntl (desc, F_SETFD, newflags) != -1)
+        return 0;
     }
 
   return -1;
 
-#else
+#else /* !F_SETFD */
 
+  /* Use dup2 to reject invalid file descriptors; the cloexec flag
+     will be unaffected.  */
+  if (desc < 0)
+    {
+      errno = EBADF;
+      return -1;
+    }
+  if (dup2 (desc, desc) < 0)
+    /* errno is EBADF here.  */
+    return -1;
+
+  /* There is nothing we can do on this kind of platform.  Punt.  */
   return 0;
-
-#endif
+#endif /* !F_SETFD */
+}
+
+
+/* Duplicates a file handle FD, while marking the copy to be closed
+   prior to exec or spawn.  Returns -1 and sets errno if FD could not
+   be duplicated.  */
+
+int
+dup_cloexec (int fd)
+{
+  return fcntl (fd, F_DUPFD_CLOEXEC, 0);
 }