[LTP] [PATCH v3] close: add test for double close EBADF

Jinseok Kim
2026-04-13T16:55:46Z

Verify that calling close() on an already closed file descriptor fails
with EBADF.

This test adds coverage for a common state transition case where a
previously valid file descriptor becomes invalid after close().

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
Changes in v3:
- Add O_RDWR flag to SAFE_OPEN
- Link to v2: https://lore.kernel.org/ltp/20260411110405.7330-1-always.starving0@gmail.com

Changes in v2:
- Add additional test coverage to close02 instead of creating a separate
close03 test.
- Link to v1: https://lore.kernel.org/ltp/20260406133134.17238-2-always.starving0@gmail.com
---
testcases/kernel/syscalls/close/close02.c | 42 ++++++++++++++++++++---
1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/testcases/kernel/syscalls/close/close02.c b/testcases/kernel/syscalls/close/close02.c
index 617c48237..3b3c61b1e 100644
--- a/testcases/kernel/syscalls/close/close02.c
+++ b/testcases/kernel/syscalls/close/close02.c
@@ -5,17 +5,51 @@
*/

/*\
- * Call close(-1) and expects it to return EBADF.
+ * Verify :manpage:`close(2)` failure cases:
+ *
+ * 1) close(-1) returns EBADF.
+ * 2) closing the same fd twice returns EBADF on the second call.
*/

#include <errno.h>
+#include <fcntl.h>
+
#include "tst_test.h"

-static void run(void)
+enum case_type {
+ INVALID_FD,
+ DOUBLE_CLOSE,
+};
+
+static struct tcase {
+ const char *desc;
+ enum case_type type;
+} tcases[] = {
+ { "close(-1)", INVALID_FD },
+ { "close same fd twice", DOUBLE_CLOSE },
+};
+
+static void verify_close(unsigned int i)
{
- TST_EXP_FAIL(close(-1), EBADF);
+ int fd;
+ struct tcase *tc = &tcases[i];
+
+ switch (tc->type) {
+ case INVALID_FD:
+ TST_EXP_FAIL(close(-1), EBADF, "%s", tc->desc);
+ break;
+
+ case DOUBLE_CLOSE:
+ fd = SAFE_OPEN("close02", O_CREAT | O_RDWR, 0600);
+
+ TST_EXP_PASS(close(fd), "%s: first close()", tc->desc);
+ TST_EXP_FAIL(close(fd), EBADF, "%s: second close()", tc->desc);
+ break;
+ }
}

static struct tst_test test = {
- .test_all = run,
+ .needs_tmpdir = 1,
+ .tcnt = ARRAY_SIZE(tcases),
+ .test = verify_close,
};
--
2.43.0