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-rw-r--r--tools/testing/selftests/pidfd/pidfd_wait.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c
new file mode 100644
index 000000000..0dcb8365d
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_wait.c
@@ -0,0 +1,233 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "pidfd.h"
+#include "../kselftest_harness.h"
+
+#define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr)))
+
+/* Attempt to de-conflict with the selftests tree. */
+#ifndef SKIP
+#define SKIP(s, ...) XFAIL(s, ##__VA_ARGS__)
+#endif
+
+static pid_t sys_clone3(struct clone_args *args)
+{
+ return syscall(__NR_clone3, args, sizeof(struct clone_args));
+}
+
+static int sys_waitid(int which, pid_t pid, siginfo_t *info, int options,
+ struct rusage *ru)
+{
+ return syscall(__NR_waitid, which, pid, info, options, ru);
+}
+
+TEST(wait_simple)
+{
+ int pidfd = -1;
+ pid_t parent_tid = -1;
+ struct clone_args args = {
+ .parent_tid = ptr_to_u64(&parent_tid),
+ .pidfd = ptr_to_u64(&pidfd),
+ .flags = CLONE_PIDFD | CLONE_PARENT_SETTID,
+ .exit_signal = SIGCHLD,
+ };
+ pid_t pid;
+ siginfo_t info = {
+ .si_signo = 0,
+ };
+
+ pidfd = open("/proc/self", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
+ ASSERT_GE(pidfd, 0);
+
+ pid = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ ASSERT_NE(pid, 0);
+ EXPECT_EQ(close(pidfd), 0);
+ pidfd = -1;
+
+ pidfd = open("/dev/null", O_RDONLY | O_CLOEXEC);
+ ASSERT_GE(pidfd, 0);
+
+ pid = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ ASSERT_NE(pid, 0);
+ EXPECT_EQ(close(pidfd), 0);
+ pidfd = -1;
+
+ pid = sys_clone3(&args);
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0)
+ exit(EXIT_SUCCESS);
+
+ pid = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ ASSERT_GE(pid, 0);
+ ASSERT_EQ(WIFEXITED(info.si_status), true);
+ ASSERT_EQ(WEXITSTATUS(info.si_status), 0);
+ EXPECT_EQ(close(pidfd), 0);
+
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_EXITED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+}
+
+TEST(wait_states)
+{
+ int pidfd = -1;
+ pid_t parent_tid = -1;
+ struct clone_args args = {
+ .parent_tid = ptr_to_u64(&parent_tid),
+ .pidfd = ptr_to_u64(&pidfd),
+ .flags = CLONE_PIDFD | CLONE_PARENT_SETTID,
+ .exit_signal = SIGCHLD,
+ };
+ int pfd[2];
+ pid_t pid;
+ siginfo_t info = {
+ .si_signo = 0,
+ };
+
+ ASSERT_EQ(pipe(pfd), 0);
+ pid = sys_clone3(&args);
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0) {
+ char buf[2];
+
+ close(pfd[1]);
+ kill(getpid(), SIGSTOP);
+ ASSERT_EQ(read(pfd[0], buf, 1), 1);
+ close(pfd[0]);
+ kill(getpid(), SIGSTOP);
+ exit(EXIT_SUCCESS);
+ }
+
+ close(pfd[0]);
+ ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0);
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_STOPPED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+
+ ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0);
+
+ ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0);
+ ASSERT_EQ(write(pfd[1], "C", 1), 1);
+ close(pfd[1]);
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_CONTINUED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+
+ ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WUNTRACED, NULL), 0);
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_STOPPED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+
+ ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0), 0);
+
+ ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL), 0);
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_KILLED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+
+ EXPECT_EQ(close(pidfd), 0);
+}
+
+TEST(wait_nonblock)
+{
+ int pidfd;
+ unsigned int flags = 0;
+ pid_t parent_tid = -1;
+ struct clone_args args = {
+ .parent_tid = ptr_to_u64(&parent_tid),
+ .flags = CLONE_PARENT_SETTID,
+ .exit_signal = SIGCHLD,
+ };
+ int ret;
+ pid_t pid;
+ siginfo_t info = {
+ .si_signo = 0,
+ };
+
+ /*
+ * Callers need to see ECHILD with non-blocking pidfds when no child
+ * processes exists.
+ */
+ pidfd = sys_pidfd_open(getpid(), PIDFD_NONBLOCK);
+ EXPECT_GE(pidfd, 0) {
+ /* pidfd_open() doesn't support PIDFD_NONBLOCK. */
+ ASSERT_EQ(errno, EINVAL);
+ SKIP(return, "Skipping PIDFD_NONBLOCK test");
+ }
+
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ ASSERT_LT(ret, 0);
+ ASSERT_EQ(errno, ECHILD);
+ EXPECT_EQ(close(pidfd), 0);
+
+ pid = sys_clone3(&args);
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0) {
+ kill(getpid(), SIGSTOP);
+ exit(EXIT_SUCCESS);
+ }
+
+ pidfd = sys_pidfd_open(pid, PIDFD_NONBLOCK);
+ EXPECT_GE(pidfd, 0) {
+ /* pidfd_open() doesn't support PIDFD_NONBLOCK. */
+ ASSERT_EQ(errno, EINVAL);
+ SKIP(return, "Skipping PIDFD_NONBLOCK test");
+ }
+
+ flags = fcntl(pidfd, F_GETFL, 0);
+ ASSERT_GT(flags, 0);
+ ASSERT_GT((flags & O_NONBLOCK), 0);
+
+ /*
+ * Callers need to see EAGAIN/EWOULDBLOCK with non-blocking pidfd when
+ * child processes exist but none have exited.
+ */
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL);
+ ASSERT_LT(ret, 0);
+ ASSERT_EQ(errno, EAGAIN);
+
+ /*
+ * Callers need to continue seeing 0 with non-blocking pidfd and
+ * WNOHANG raised explicitly when child processes exist but none have
+ * exited.
+ */
+ ret = sys_waitid(P_PIDFD, pidfd, &info, WEXITED | WNOHANG, NULL);
+ ASSERT_EQ(ret, 0);
+
+ ASSERT_EQ(fcntl(pidfd, F_SETFL, (flags & ~O_NONBLOCK)), 0);
+
+ ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0);
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_STOPPED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+
+ ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0);
+
+ ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WEXITED, NULL), 0);
+ ASSERT_EQ(info.si_signo, SIGCHLD);
+ ASSERT_EQ(info.si_code, CLD_EXITED);
+ ASSERT_EQ(info.si_pid, parent_tid);
+
+ EXPECT_EQ(close(pidfd), 0);
+}
+
+TEST_HARNESS_MAIN