tests: port large-fd POSIX spawn tests to OS X

Problem reported by Daiki Ueno in
<http://lists.gnu.org/archive/html/bug-gnulib/2013-06/msg00031.html>.
* tests/test-posix_spawn_file_actions_addclose.c:
* tests/test-posix_spawn_file_actions_adddup2.c:
* tests/test-posix_spawn_file_actions_addopen.c:
Include <limits.h>, for OPEN_MAX, if available.
(big_fd): New static function.
(main): Use it.

3 files changed, 50 insertions, 4 deletions

diff --git a/tests/test-posix_spawn_file_actions_addclose.c b/tests/test-posix_spawn_file_actions_addclose.c
index 47b12d0f2b..296f10132c 100644
--- a/tests/test-posix_spawn_file_actions_addclose.c
+++ b/tests/test-posix_spawn_file_actions_addclose.c
@@ -23,10 +23,25 @@ SIGNATURE_CHECK (posix_spawn_file_actions_addclose, int,
                  (posix_spawn_file_actions_t *, int));
 
 #include <errno.h>
+#include <limits.h>
 #include <unistd.h>
 
 #include "macros.h"
 
+/* Return a file descriptor that is too big to use.
+   Prefer the smallest such fd, except use OPEN_MAX if it is defined
+   and is greater than getdtablesize (), as that's how OS X works.  */
+static int
+big_fd (void)
+{
+  int fd = getdtablesize ();
+#ifdef OPEN_MAX
+  if (fd < OPEN_MAX)
+    fd = OPEN_MAX;
+#endif
+  return fd;
+}
+
 int
 main (void)
 {
@@ -40,9 +55,9 @@ main (void)
     ASSERT (posix_spawn_file_actions_addclose (&actions, -1) == EBADF);
   }
   {
+    int bad_fd = big_fd ();
     errno = 0;
-    ASSERT (posix_spawn_file_actions_addclose (&actions, getdtablesize ())
-            == EBADF);
+    ASSERT (posix_spawn_file_actions_addclose (&actions, bad_fd) == EBADF);
   }
 
   return 0;
diff --git a/tests/test-posix_spawn_file_actions_adddup2.c b/tests/test-posix_spawn_file_actions_adddup2.c
index d728eff61c..fe33c02589 100644
--- a/tests/test-posix_spawn_file_actions_adddup2.c
+++ b/tests/test-posix_spawn_file_actions_adddup2.c
@@ -23,14 +23,29 @@ SIGNATURE_CHECK (posix_spawn_file_actions_adddup2, int,
                  (posix_spawn_file_actions_t *, int, int));
 
 #include <errno.h>
+#include <limits.h>
 #include <unistd.h>
 
 #include "macros.h"
 
+/* Return a file descriptor that is too big to use.
+   Prefer the smallest such fd, except use OPEN_MAX if it is defined
+   and is greater than getdtablesize (), as that's how OS X works.  */
+static int
+big_fd (void)
+{
+  int fd = getdtablesize ();
+#ifdef OPEN_MAX
+  if (fd < OPEN_MAX)
+    fd = OPEN_MAX;
+#endif
+  return fd;
+}
+
 int
 main (void)
 {
-  int bad_fd = getdtablesize ();
+  int bad_fd = big_fd ();
   posix_spawn_file_actions_t actions;
 
   ASSERT (posix_spawn_file_actions_init (&actions) == 0);
diff --git a/tests/test-posix_spawn_file_actions_addopen.c b/tests/test-posix_spawn_file_actions_addopen.c
index c2329d4fc1..a4865ca97e 100644
--- a/tests/test-posix_spawn_file_actions_addopen.c
+++ b/tests/test-posix_spawn_file_actions_addopen.c
@@ -25,10 +25,25 @@ SIGNATURE_CHECK (posix_spawn_file_actions_addopen, int,
 
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <unistd.h>
 
 #include "macros.h"
 
+/* Return a file descriptor that is too big to use.
+   Prefer the smallest such fd, except use OPEN_MAX if it is defined
+   and is greater than getdtablesize (), as that's how OS X works.  */
+static int
+big_fd (void)
+{
+  int fd = getdtablesize ();
+#ifdef OPEN_MAX
+  if (fd < OPEN_MAX)
+    fd = OPEN_MAX;
+#endif
+  return fd;
+}
+
 int
 main (void)
 {
@@ -44,8 +59,9 @@ main (void)
             == EBADF);
   }
   {
+    int bad_fd = big_fd ();
     errno = 0;
-    ASSERT (posix_spawn_file_actions_addopen (&actions, getdtablesize (),
+    ASSERT (posix_spawn_file_actions_addopen (&actions, bad_fd,
                                               "foo", 0, O_RDONLY)
             == EBADF);
   }