Add a selftest for PIDFD_INFO_EXIT behavior.
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
tools/testing/selftests/pidfd/pidfd.h | 4 +
tools/testing/selftests/pidfd/pidfd_info_test.c | 151 ++++++++++++++++++++++++
2 files changed, 155 insertions(+)
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index cc8e381978df..fee6fd3e67dd 100644
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -131,6 +131,10 @@
#define PIDFD_INFO_EXIT (1UL << 3) /* Always returned if available, even if not requested */
#endif
+#ifndef PIDFD_THREAD
+#define PIDFD_THREAD O_EXCL
+#endif
+
struct pidfd_info {
__u64 mask;
__u64 cgroupid;
diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c
index 16e4be2364df..5e86e3df323b 100644
--- a/tools/testing/selftests/pidfd/pidfd_info_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_info_test.c
@@ -218,4 +218,155 @@ TEST_F(pidfd_info, success_reaped_poll)
ASSERT_EQ(WTERMSIG(info.exit_code), SIGKILL);
}
+static void *pidfd_info_pause_thread(void *arg)
+{
+ pid_t pid_thread = gettid();
+ int ipc_socket = *(int *)arg;
+
+ /* Inform the grand-parent what the tid of this thread is. */
+ if (write_nointr(ipc_socket, &pid_thread, sizeof(pid_thread)) != sizeof(pid_thread))
+ return NULL;
+
+ close(ipc_socket);
+
+ /* Sleep untill we're killed. */
+ pause();
+ return NULL;
+}
+
+TEST_F(pidfd_info, thread_group)
+{
+ pid_t pid_leader, pid_thread;
+ pthread_t thread;
+ int nevents, pidfd_leader, pidfd_thread, pidfd_leader_thread, ret;
+ int ipc_sockets[2];
+ struct pollfd fds = {};
+ struct pidfd_info info = {
+ .mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT,
+ }, info2;
+
+ ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+ EXPECT_EQ(ret, 0);
+
+ pid_leader = create_child(&pidfd_leader, 0);
+ EXPECT_GE(pid_leader, 0);
+
+ if (pid_leader == 0) {
+ close(ipc_sockets[0]);
+
+ /* The thread will outlive the thread-group leader. */
+ if (pthread_create(&thread, NULL, pidfd_info_pause_thread, &ipc_sockets[1]))
+ syscall(__NR_exit, EXIT_FAILURE);
+
+ /* Make the thread-group leader exit prematurely. */
+ syscall(__NR_exit, EXIT_SUCCESS);
+ }
+
+ /* Retrieve the tid of the thread. */
+ EXPECT_EQ(close(ipc_sockets[1]), 0);
+ ASSERT_EQ(read_nointr(ipc_sockets[0], &pid_thread, sizeof(pid_thread)), sizeof(pid_thread));
+ EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+ /* Opening a thread as a thread-group leader must fail. */
+ pidfd_thread = sys_pidfd_open(pid_thread, 0);
+ ASSERT_LT(pidfd_thread, 0);
+
+ /* Opening a thread as a PIDFD_THREAD must succeed. */
+ pidfd_thread = sys_pidfd_open(pid_thread, PIDFD_THREAD);
+ ASSERT_GE(pidfd_thread, 0);
+
+ /*
+ * Opening a PIDFD_THREAD aka thread-specific pidfd based on a
+ * thread-group leader must succeed.
+ */
+ pidfd_leader_thread = sys_pidfd_open(pid_leader, PIDFD_THREAD);
+ ASSERT_GE(pidfd_leader_thread, 0);
+
+ /*
+ * Note that pidfd_leader is a thread-group pidfd, so polling on it
+ * would only notify us once all thread in the thread-group have
+ * exited. So we can't poll before we have taken down the whole
+ * thread-group.
+ */
+
+ /* Get PIDFD_GET_INFO using the thread-group leader pidfd. */
+ ASSERT_EQ(ioctl(pidfd_leader, PIDFD_GET_INFO, &info), 0);
+ ASSERT_TRUE(!!(info.mask & PIDFD_INFO_CREDS));
+ /* Process has exited but not been reaped, so no PIDFD_INFO_EXIT information yet. */
+ ASSERT_FALSE(!!(info.mask & PIDFD_INFO_EXIT));
+ ASSERT_EQ(info.pid, pid_leader);
+
+ /*
+ * Now retrieve the same info using the thread specific pidfd
+ * for the thread-group leader.
+ */
+ info2.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT;
+ ASSERT_EQ(ioctl(pidfd_leader_thread, PIDFD_GET_INFO, &info2), 0);
+ ASSERT_TRUE(!!(info2.mask & PIDFD_INFO_CREDS));
+ /* Process has exited but not been reaped, so no PIDFD_INFO_EXIT information yet. */
+ ASSERT_FALSE(!!(info2.mask & PIDFD_INFO_EXIT));
+ ASSERT_EQ(info2.pid, pid_leader);
+
+ /* Now try the thread-specific pidfd. */
+ ASSERT_EQ(ioctl(pidfd_thread, PIDFD_GET_INFO, &info), 0);
+ ASSERT_TRUE(!!(info.mask & PIDFD_INFO_CREDS));
+ /* The thread hasn't exited, so no PIDFD_INFO_EXIT information yet. */
+ ASSERT_FALSE(!!(info.mask & PIDFD_INFO_EXIT));
+ ASSERT_EQ(info.pid, pid_thread);
+
+ /*
+ * Take down the whole thread-group. The thread-group leader
+ * exited successfully but the thread will now be SIGKILLed.
+ * This must be reflected in the recorded exit information.
+ */
+ EXPECT_EQ(sys_pidfd_send_signal(pidfd_leader, SIGKILL, NULL, 0), 0);
+ EXPECT_EQ(sys_waitid(P_PIDFD, pidfd_leader, NULL, WEXITED), 0);
+
+ fds.events = POLLIN;
+ fds.fd = pidfd_leader;
+ nevents = poll(&fds, 1, -1);
+ ASSERT_EQ(nevents, 1);
+ ASSERT_TRUE(!!(fds.revents & POLLIN));
+ /* The thread-group leader has been reaped. */
+ ASSERT_TRUE(!!(fds.revents & POLLHUP));
+
+ /*
+ * Retrieve exit information for the thread-group leader via the
+ * thread-group leader pidfd.
+ */
+ info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT;
+ ASSERT_EQ(ioctl(pidfd_leader, PIDFD_GET_INFO, &info), 0);
+ ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS));
+ ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT));
+ /* The thread-group leader exited successfully. Only the specific thread was SIGKILLed. */
+ ASSERT_TRUE(WIFEXITED(info.exit_code));
+ ASSERT_EQ(WEXITSTATUS(info.exit_code), 0);
+
+ /*
+ * Retrieve exit information for the thread-group leader via the
+ * thread-specific pidfd.
+ */
+ info2.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT;
+ ASSERT_EQ(ioctl(pidfd_leader_thread, PIDFD_GET_INFO, &info2), 0);
+ ASSERT_FALSE(!!(info2.mask & PIDFD_INFO_CREDS));
+ ASSERT_TRUE(!!(info2.mask & PIDFD_INFO_EXIT));
+
+ /* The thread-group leader exited successfully. Only the specific thread was SIGKILLed. */
+ ASSERT_TRUE(WIFEXITED(info2.exit_code));
+ ASSERT_EQ(WEXITSTATUS(info2.exit_code), 0);
+
+ /* Retrieve exit information for the thread. */
+ info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT;
+ ASSERT_EQ(ioctl(pidfd_thread, PIDFD_GET_INFO, &info), 0);
+ ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS));
+ ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT));
+
+ /* The thread got SIGKILLed. */
+ ASSERT_TRUE(WIFSIGNALED(info.exit_code));
+ ASSERT_EQ(WTERMSIG(info.exit_code), SIGKILL);
+
+ EXPECT_EQ(close(pidfd_leader), 0);
+ EXPECT_EQ(close(pidfd_thread), 0);
+}
+
TEST_HARNESS_MAIN
--
2.47.2
