selftests/pidfd: add first PIDFD_INFO_EXIT selftest

Add a selftest for PIDFD_INFO_EXIT behavior.

Link: https://lore.kernel.org/r/20250305-work-pidfs-kill_on_last_close-v3-10-c8c3d8361705@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/tools/testing/selftests/pidfd/.gitignore b/tools/testing/selftests/pidfd/.gitignore
index bf92481f925c32ad4b2e49a9183711ec235bdadc..bddae1d4d7e438d18a048d88bd32e896c18376e1 100644 (file)
--- a/tools/testing/selftests/pidfd/.gitignore
+++ b/tools/testing/selftests/pidfd/.gitignore
@@ -8,3 +8,4 @@ pidfd_getfd_test
 pidfd_setns_test
 pidfd_file_handle_test
 pidfd_bind_mount
+pidfd_info_test

diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile
index 301343a11b62ecdf25d9f8ffeba690b84dc5c378..a94c2bc8d59411b350edbdc6ec261690d9364412 100644 (file)
--- a/tools/testing/selftests/pidfd/Makefile
+++ b/tools/testing/selftests/pidfd/Makefile
@@ -3,7 +3,7 @@ CFLAGS += -g $(KHDR_INCLUDES) -pthread -Wall
 
 TEST_GEN_PROGS := pidfd_test pidfd_fdinfo_test pidfd_open_test \
        pidfd_poll_test pidfd_wait pidfd_getfd_test pidfd_setns_test \
-       pidfd_file_handle_test pidfd_bind_mount
+       pidfd_file_handle_test pidfd_bind_mount pidfd_info_test
 
 include ../lib.mk
 

diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index bad518766aa51e13f4a165343a540064ed0493e2..cc8e381978df8e96bf2501b0db381f86ca109050 100644 (file)
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -127,6 +127,10 @@
 #define PIDFD_INFO_CGROUPID            (1UL << 2) /* Always returned if available, even if not requested */
 #endif
 
+#ifndef PIDFD_INFO_EXIT
+#define PIDFD_INFO_EXIT                        (1UL << 3) /* Always returned if available, even if not requested */
+#endif
+
 struct pidfd_info {
        __u64 mask;
        __u64 cgroupid;
@@ -141,7 +145,7 @@ struct pidfd_info {
        __u32 sgid;
        __u32 fsuid;
        __u32 fsgid;
-       __u32 spare0[1];
+       __s32 exit_code;
 };
 
 /*

diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c
new file mode 100644 (file)
index 0000000..cc1d3d5
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_info_test.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <linux/types.h>
+#include <poll.h>
+#include <pthread.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <linux/kcmp.h>
+#include <sys/stat.h>
+
+#include "pidfd.h"
+#include "../kselftest_harness.h"
+
+FIXTURE(pidfd_info)
+{
+       pid_t child_pid1;
+       int child_pidfd1;
+
+       pid_t child_pid2;
+       int child_pidfd2;
+
+       pid_t child_pid3;
+       int child_pidfd3;
+
+       pid_t child_pid4;
+       int child_pidfd4;
+};
+
+FIXTURE_SETUP(pidfd_info)
+{
+       int ret;
+       int ipc_sockets[2];
+       char c;
+
+       ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+       EXPECT_EQ(ret, 0);
+
+       self->child_pid1 = create_child(&self->child_pidfd1, 0);
+       EXPECT_GE(self->child_pid1, 0);
+
+       if (self->child_pid1 == 0) {
+               close(ipc_sockets[0]);
+
+               if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+                       _exit(EXIT_FAILURE);
+
+               close(ipc_sockets[1]);
+
+               pause();
+               _exit(EXIT_SUCCESS);
+       }
+
+       EXPECT_EQ(close(ipc_sockets[1]), 0);
+       ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+       EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+       /* SIGKILL but don't reap. */
+       EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd1, SIGKILL, NULL, 0), 0);
+
+       ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
+       EXPECT_EQ(ret, 0);
+
+       self->child_pid2 = create_child(&self->child_pidfd2, 0);
+       EXPECT_GE(self->child_pid2, 0);
+
+       if (self->child_pid2 == 0) {
+               close(ipc_sockets[0]);
+
+               if (write_nointr(ipc_sockets[1], "1", 1) < 0)
+                       _exit(EXIT_FAILURE);
+
+               close(ipc_sockets[1]);
+
+               pause();
+               _exit(EXIT_SUCCESS);
+       }
+
+       EXPECT_EQ(close(ipc_sockets[1]), 0);
+       ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
+       EXPECT_EQ(close(ipc_sockets[0]), 0);
+
+       /* SIGKILL and reap. */
+       EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd2, SIGKILL, NULL, 0), 0);
+       EXPECT_EQ(sys_waitid(P_PID, self->child_pid2, NULL, WEXITED), 0);
+
+       self->child_pid3 = create_child(&self->child_pidfd3, CLONE_NEWUSER | CLONE_NEWPID);
+       EXPECT_GE(self->child_pid3, 0);
+
+       if (self->child_pid3 == 0)
+               _exit(EXIT_SUCCESS);
+
+       self->child_pid4 = create_child(&self->child_pidfd4, CLONE_NEWUSER | CLONE_NEWPID);
+       EXPECT_GE(self->child_pid4, 0);
+
+       if (self->child_pid4 == 0)
+               _exit(EXIT_SUCCESS);
+
+       EXPECT_EQ(sys_waitid(P_PID, self->child_pid4, NULL, WEXITED), 0);
+}
+
+FIXTURE_TEARDOWN(pidfd_info)
+{
+       sys_pidfd_send_signal(self->child_pidfd1, SIGKILL, NULL, 0);
+       if (self->child_pidfd1 >= 0)
+               EXPECT_EQ(0, close(self->child_pidfd1));
+
+       sys_waitid(P_PID, self->child_pid1, NULL, WEXITED);
+
+       sys_pidfd_send_signal(self->child_pidfd2, SIGKILL, NULL, 0);
+       if (self->child_pidfd2 >= 0)
+               EXPECT_EQ(0, close(self->child_pidfd2));
+
+       sys_waitid(P_PID, self->child_pid2, NULL, WEXITED);
+       sys_waitid(P_PID, self->child_pid3, NULL, WEXITED);
+       sys_waitid(P_PID, self->child_pid4, NULL, WEXITED);
+}
+
+TEST_F(pidfd_info, sigkill_exit)
+{
+       struct pidfd_info info = {
+               .mask = PIDFD_INFO_CGROUPID,
+       };
+
+       /* Process has exited but not been reaped so this must work. */
+       ASSERT_EQ(ioctl(self->child_pidfd1, PIDFD_GET_INFO, &info), 0);
+
+       info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT;
+       ASSERT_EQ(ioctl(self->child_pidfd1, 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));
+}
+
+TEST_HARNESS_MAIN