[LTP] [PATCH v3 7/7] syscalls/pidfd_getfd02: Add basic error test

[Yang Xu]

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 runtest/syscalls                              |   1 +
 .../kernel/syscalls/pidfd_getfd/.gitignore    |   1 +
 .../syscalls/pidfd_getfd/pidfd_getfd02.c      | 111 ++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 testcases/kernel/syscalls/pidfd_getfd/pidfd_getfd02.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 126c33fc1..b80786499 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -952,6 +952,7 @@ personality01 personality01
 personality02 personality02
 
 pidfd_getfd01 pidfd_getfd01
+pidfd_getfd02 pidfd_getfd02
 
 pidfd_open01 pidfd_open01
 pidfd_open02 pidfd_open02
diff --git a/testcases/kernel/syscalls/pidfd_getfd/.gitignore b/testcases/kernel/syscalls/pidfd_getfd/.gitignore
index 9328942ac..8ef904202 100644
--- a/testcases/kernel/syscalls/pidfd_getfd/.gitignore
+++ b/testcases/kernel/syscalls/pidfd_getfd/.gitignore
@@ -1 +1,2 @@
 /pidfd_getfd01
+/pidfd_getfd02
diff --git a/testcases/kernel/syscalls/pidfd_getfd/pidfd_getfd02.c b/testcases/kernel/syscalls/pidfd_getfd/pidfd_getfd02.c
new file mode 100644
index 000000000..805085cda
--- /dev/null
+++ b/testcases/kernel/syscalls/pidfd_getfd/pidfd_getfd02.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <xuyang2018.jy@fujitsu.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Tests basic error handling of the pidfd_open syscall.
+ *
+ * - EBADF pidfd is not a valid PID file descriptor
+ * - EBADF targetfd is not an open file descriptor in the process referred
+ *   to by pidfd
+ * - EINVAL flags is not 0
+ * - ESRCH the process referred to by pidfd does not exist (it has terminated
+ *   and been waited on))
+ * - EPERM the calling process doesn't have PTRACE_MODE_ATTACH_REALCREDS permissions
+ *   over the process referred to by pidfd
+ */
+
+#include <stdlib.h>
+#include <pwd.h>
+#include "tst_test.h"
+#include "tst_safe_pidfd.h"
+
+static int valid_pidfd = -1, invalid_pidfd = -1, pidfd = -1;
+static uid_t uid;
+
+static struct tcase {
+	char *name;
+	int *pidfd;
+	int targetfd;
+	int flags;
+	int exp_errno;
+} tcases[] = {
+	{"invalid pidfd", &invalid_pidfd, 0, 0, EBADF},
+	{"invalid targetfd", &valid_pidfd, -1, 0, EBADF},
+	{"invalid flags", &valid_pidfd, 0, 1, EINVAL},
+	{"the process referred to by pidfd doesn't exist", NULL, 0, 0, ESRCH},
+	{"lack of required permission", &valid_pidfd, 0, 0, EPERM},
+};
+
+static void setup(void)
+{
+	pidfd_open_supported();
+	pidfd_getfd_supported();
+
+	struct passwd *pw;
+
+	pw = SAFE_GETPWNAM("nobody");
+	uid = pw->pw_uid;
+
+	valid_pidfd = SAFE_PIDFD_OPEN(getpid(), 0);
+}
+
+static void cleanup(void)
+{
+	if (valid_pidfd > -1)
+		SAFE_CLOSE(valid_pidfd);
+	if (pidfd > -1)
+		SAFE_CLOSE(pidfd);
+}
+
+static void run(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+	int pid;
+
+	if (tc->exp_errno == EPERM) {
+		pid = SAFE_FORK();
+		if (!pid) {
+			SAFE_SETUID(uid);
+			TST_EXP_FAIL2(pidfd_getfd(valid_pidfd, tc->targetfd, tc->flags),
+				tc->exp_errno, "pidfd_getfd(%d, %d, %d) with %s",
+				valid_pidfd, tc->targetfd, tc->flags, tc->name);
+			TST_CHECKPOINT_WAKE(0);
+			exit(0);
+		}
+		TST_CHECKPOINT_WAIT(0);
+		SAFE_WAIT(NULL);
+		return;
+	} else if (tc->exp_errno == ESRCH) {
+		pid = SAFE_FORK();
+		if (!pid) {
+			TST_CHECKPOINT_WAIT(0);
+			exit(0);
+		}
+		pidfd = SAFE_PIDFD_OPEN(pid, 0);
+		TST_CHECKPOINT_WAKE(0);
+		SAFE_WAIT(NULL);
+		TST_EXP_FAIL2(pidfd_getfd(pidfd, tc->targetfd, tc->flags),
+			tc->exp_errno, "pidfd_getfd(%d, %d, %d) with %s",
+			pidfd, tc->targetfd, tc->flags, tc->name);
+		SAFE_CLOSE(pidfd);
+	} else	{
+		TST_EXP_FAIL2(pidfd_getfd(*tc->pidfd, tc->targetfd, tc->flags),
+			tc->exp_errno, "pidfd_getfd(%d, %d, %d) with %s",
+			*tc->pidfd, tc->targetfd, tc->flags, tc->name);
+	}
+}
+
+static struct tst_test test = {
+	.tcnt = ARRAY_SIZE(tcases),
+	.test = run,
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.forks_child = 1,
+	.needs_checkpoints = 1,
+};
-- 
2.31.1