Move io/tst-fcntl temporary file creation to do_prepare.

This patch makes the io/tst-fcntl test create its temporary file in
do_prepare not do_test, so that add_temp_name is called in the parent
on the correct file name, as requested in the thread starting at
<https://sourceware.org/ml/libc-alpha/2015-10/msg00552.html>.  I don't
see any reason in this test that opening the file in the parent should
be problematic.

This patch is explicitly not exhaustive for such issues; other tests
still call add_temp_file in the child.  The general issue is noted at
<https://sourceware.org/glibc/wiki/Development_Todo/Master#Use_test-skeleton.c>.

Tested for x86_64 (that this test still passes and no longer leaves a
file behind in /tmp).

	* io/tst-fcntl.c (fd): New static variable.
	(do_prepare): Open temporary file here....
	(do_test): ...not here.

2 files changed, 14 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 66a0cce49f..015f564ae2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2015-10-21  Joseph Myers  <joseph@codesourcery.com>
 
+	* io/tst-fcntl.c (fd): New static variable.
+	(do_prepare): Open temporary file here....
+	(do_test): ...not here.
+
 	* io/ftwtest-sh: Also trap on exit to remove temporary files.
 
 2015-10-21  H.J. Lu  <hongjiu.lu@intel.com>
diff --git a/io/tst-fcntl.c b/io/tst-fcntl.c
index dfdb42eea4..8814b17ad3 100644
--- a/io/tst-fcntl.c
+++ b/io/tst-fcntl.c
@@ -38,6 +38,9 @@ extern int do_test (int argc, char *argv[]);
 /* Name of the temporary files.  */
 static char *name;
 
+/* File descriptor to temporary file.  */
+static int fd;
+
 void
 do_prepare (int argc, char *argv[])
 {
@@ -47,6 +50,13 @@ do_prepare (int argc, char *argv[])
    name = malloc (name_len + sizeof ("/fcntlXXXXXX"));
    mempcpy (mempcpy (name, test_dir, name_len),
 	    "/fcntlXXXXXX", sizeof ("/fcntlXXXXXX"));
+  /* Create the temporary file.  */
+  fd = mkstemp (name);
+  if (fd == -1)
+    {
+      printf ("cannot open temporary file: %m\n");
+      exit (1);
+    }
    add_temp_file (name);
 }
 
@@ -54,20 +64,12 @@ do_prepare (int argc, char *argv[])
 int
 do_test (int argc, char *argv[])
 {
-  int fd;
   int fd2;
   int fd3;
   struct stat64 st;
   int val;
   int result = 0;
 
-  /* Create the temporary file.  */
-  fd = mkstemp (name);
-  if (fd == -1)
-    {
-      printf ("cannot open temporary file: %m\n");
-      return 1;
-    }
   if (fstat64 (fd, &st) != 0)
     {
       printf ("cannot stat test file: %m\n");