[LTP] [PATCH v4 5/8] Add ioctl_pidfd03 test

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

Verify that ioctl() returns ESRCH when a process attempts to access
the exit status of an isolated child using `PIDFD_GET_INFO` and
`PIDFD_INFO_EXIT` is not defined in `struct pidfd_info`.

Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 runtest/syscalls                                |  1 +
 testcases/kernel/syscalls/ioctl/.gitignore      |  1 +
 testcases/kernel/syscalls/ioctl/ioctl_pidfd03.c | 64 +++++++++++++++++++++++++
 3 files changed, 66 insertions(+)

diff --git a/runtest/syscalls b/runtest/syscalls
index fbb38b1a52ed9d7f6634336d83c226b5cce522e8..7e019675216a59919b137b84b023ebb2969efcdb 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -615,6 +615,7 @@ ioctl_fiemap01 ioctl_fiemap01
 
 ioctl_pidfd01 ioctl_pidfd01
 ioctl_pidfd02 ioctl_pidfd02
+ioctl_pidfd03 ioctl_pidfd03
 
 inotify_init1_01 inotify_init1_01
 inotify_init1_02 inotify_init1_02
diff --git a/testcases/kernel/syscalls/ioctl/.gitignore b/testcases/kernel/syscalls/ioctl/.gitignore
index a984744a67173b70872446823a6fdeb6a44fe2c8..393ec47fecaed101f413284f28646aeff76cc30b 100644
--- a/testcases/kernel/syscalls/ioctl/.gitignore
+++ b/testcases/kernel/syscalls/ioctl/.gitignore
@@ -32,3 +32,4 @@
 /ioctl_fiemap01
 /ioctl_pidfd01
 /ioctl_pidfd02
+/ioctl_pidfd03
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd03.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd03.c
new file mode 100644
index 0000000000000000000000000000000000000000..eca4b90f4b5fb9f209c30752ab583a20a31518bc
--- /dev/null
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd03.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2025 Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * Verify that ioctl() returns ESRCH when a process attempts to access the
+ * exit status of an isolated child using `PIDFD_GET_INFO` and
+ * `PIDFD_INFO_EXIT` is not defined in `struct pidfd_info`.
+ */
+
+#include "ioctl_pidfd.h"
+#include "lapi/sched.h"
+
+static struct tst_clone_args *args;
+static struct pidfd_info *info;
+
+static void run(void)
+{
+	int status;
+	int pidfd = 0;
+	pid_t pid_child;
+
+	memset(args, 0, sizeof(struct tst_clone_args));
+
+	args->flags = CLONE_PIDFD | CLONE_NEWUSER | CLONE_NEWPID;
+	args->pidfd = (uint64_t)&pidfd;
+	args->exit_signal = SIGCHLD;
+
+	pid_child = SAFE_CLONE(args);
+	if (!pid_child)
+		exit(100);
+
+	info->mask = 0;
+
+	/* child is not reaped, so ioctl() will pass */
+	SAFE_IOCTL(pidfd, PIDFD_GET_INFO, info);
+	TST_EXP_EQ_LI(info->mask & PIDFD_INFO_EXIT, 0);
+
+	SAFE_WAITPID(pid_child, &status, 0);
+
+	/* child is now reaped, so we get ESRCH */
+	TST_EXP_FAIL(ioctl(pidfd, PIDFD_GET_INFO, info), ESRCH);
+	TST_EXP_EQ_LI(info->mask & PIDFD_INFO_EXIT, 0);
+
+	SAFE_CLOSE(pidfd);
+}
+
+static void setup(void)
+{
+	if (!ioctl_pidfd_info_exit_supported())
+		tst_brk(TCONF, "PIDFD_INFO_EXIT is not supported by ioctl()");
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = setup,
+	.forks_child = 1,
+	.bufs = (struct tst_buffers []) {
+		{&args, .size = sizeof(*args)},
+		{&info, .size = sizeof(*info)},
+		{}
+	}
+};

-- 
2.50.1