tests: Strenghten tests with invalid file descriptor

[Bruno Haible]

Let's see whether some kernel confuses the notion of "file descriptor"
with the notion of "file descriptor or AT_FDCWD". A little bit of
"let's try to provoke undefined behaviour internally" mindset... 😉


2024-09-03  Bruno Haible  <bruno@clisp.org>

        tests: Strenghten tests with invalid file descriptor.
        * tests/test-close.c: Include <fcntl.h>.
        (main): Check that AT_FDCWD is recognized as an invalid file descriptor.
        * tests/test-dup.c: Include <fcntl.h>.
        (main): Check that AT_FDCWD is recognized as an invalid file descriptor.
        * tests/test-unlockpt.c: Include <fcntl.h>.
        (main): Check that AT_FDCWD is recognized as an invalid file descriptor.
        * tests/test-fchdir.c (main): Likewise.
        * tests/test-fdatasync.c (main): Likewise.
        * tests/test-fdopendir.c (main): Likewise.
        * tests/test-fsync.c (main): Likewise.
        * tests/test-isatty.c (main): Likewise.

diff --git a/tests/test-close.c b/tests/test-close.c
index b796e0d200..ca2c21bfe2 100644
--- a/tests/test-close.c
+++ b/tests/test-close.c
@@ -22,6 +22,7 @@
 SIGNATURE_CHECK (close, int, (int));
 
 #include <errno.h>
+#include <fcntl.h>
 
 #include "macros.h"
 
@@ -40,6 +41,13 @@ main (void)
     ASSERT (close (99) == -1);
     ASSERT (errno == EBADF);
   }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (close (AT_FDCWD) == -1);
+    ASSERT (errno == EBADF);
+  }
+#endif
 
   return test_exit_status;
 }
diff --git a/tests/test-dup.c b/tests/test-dup.c
index bf3f519bb8..884fbc605c 100644
--- a/tests/test-dup.c
+++ b/tests/test-dup.c
@@ -22,6 +22,7 @@
 SIGNATURE_CHECK (dup, int, (int));
 
 #include <errno.h>
+#include <fcntl.h>
 
 #include "macros.h"
 
@@ -40,6 +41,13 @@ main (void)
     ASSERT (dup (99) == -1);
     ASSERT (errno == EBADF);
   }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (dup (AT_FDCWD) == -1);
+    ASSERT (errno == EBADF);
+  }
+#endif
 
   return test_exit_status;
 }
diff --git a/tests/test-fchdir.c b/tests/test-fchdir.c
index 692ab5194c..0eba209c47 100644
--- a/tests/test-fchdir.c
+++ b/tests/test-fchdir.c
@@ -56,6 +56,13 @@ main (void)
     ASSERT (fchdir (99) == -1);
     ASSERT (errno == EBADF);
   }
+#ifdef FD_ATCWD
+  {
+    errno = 0;
+    ASSERT (fchdir (FD_ATCWD) == -1);
+    ASSERT (errno == EBADF);
+  }
+#endif
 
   /* Check for other failure cases.  */
   {
diff --git a/tests/test-fdatasync.c b/tests/test-fdatasync.c
index 3d55a7105b..691a198a99 100644
--- a/tests/test-fdatasync.c
+++ b/tests/test-fdatasync.c
@@ -56,6 +56,13 @@ main (void)
     ASSERT (fdatasync (99) == -1);
     ASSERT (errno == EBADF);
   }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (fdatasync (AT_FDCWD) == -1);
+    ASSERT (errno == EBADF);
+  }
+#endif
 
   fd = open (file, O_WRONLY|O_CREAT|O_TRUNC, 0644);
   ASSERT (0 <= fd);
diff --git a/tests/test-fdopendir.c b/tests/test-fdopendir.c
index 5dd8a4a967..3430d03bad 100644
--- a/tests/test-fdopendir.c
+++ b/tests/test-fdopendir.c
@@ -56,6 +56,13 @@ main ()
     ASSERT (fdopendir (99) == NULL);
     ASSERT (errno == EBADF);
   }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (fdopendir (AT_FDCWD) == NULL);
+    ASSERT (errno == EBADF);
+  }
+#endif
 
   /* This should work.  */
   fd = open (".", O_RDONLY);
diff --git a/tests/test-fsync.c b/tests/test-fsync.c
index c28a5cc6ab..7e680c274a 100644
--- a/tests/test-fsync.c
+++ b/tests/test-fsync.c
@@ -56,6 +56,13 @@ main (void)
     ASSERT (fsync (99) == -1);
     ASSERT (errno == EBADF);
   }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (fsync (AT_FDCWD) == -1);
+    ASSERT (errno == EBADF);
+  }
+#endif
 
   fd = open (file, O_WRONLY|O_CREAT|O_TRUNC, 0644);
   ASSERT (0 <= fd);
diff --git a/tests/test-isatty.c b/tests/test-isatty.c
index 1c7d6d8cd9..d844c62615 100644
--- a/tests/test-isatty.c
+++ b/tests/test-isatty.c
@@ -56,6 +56,15 @@ main (void)
             || errno == 0 /* seen on IRIX 6.5, Solaris 10 */
            );
   }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (isatty (AT_FDCWD) == 0);
+    ASSERT (errno == EBADF
+            || errno == 0 /* seen on IRIX 6.5, Solaris 10 */
+           );
+  }
+#endif
 
   /* Test behaviour for regular files.  */
   {
diff --git a/tests/test-unlockpt.c b/tests/test-unlockpt.c
index e69f72db97..8fbd36cf69 100644
--- a/tests/test-unlockpt.c
+++ b/tests/test-unlockpt.c
@@ -22,6 +22,7 @@
 SIGNATURE_CHECK (unlockpt, int, (int));
 
 #include <errno.h>
+#include <fcntl.h>
 #include <unistd.h>
 
 #include "macros.h"
@@ -46,6 +47,15 @@ main (void)
             || errno == EINVAL /* seen on FreeBSD 6.4 */
            );
   }
+# ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (unlockpt (AT_FDCWD) == -1);
+    ASSERT (errno == EBADF
+            || errno == EINVAL /* seen on FreeBSD 6.4 */
+           );
+  }
+# endif
 #endif
 
   return test_exit_status;