tools/testing/selftests/pidfd/pidfd_test.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/pidfd/pidfd_test.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/pidfd/pidfd_test.c
Extension
.c
Size
15522 bytes
Lines
629
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

if (errno == EPERM) {
			ksft_test_result_skip("%s test: Unsharing pid namespace not permitted\n",
					      test_name);
			return 0;
		}
		ksft_exit_fail_msg("%s test: Failed to unshare pid namespace\n",
				   test_name);
	}

	ret = unshare(CLONE_NEWNS);
	if (ret < 0) {
		if (errno == EPERM) {
			ksft_test_result_skip("%s test: Unsharing mount namespace not permitted\n",
					      test_name);
			return 0;
		}
		ksft_exit_fail_msg("%s test: Failed to unshare mount namespace\n",
				   test_name);
	}

	ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
	if (ret < 0)
		ksft_exit_fail_msg("%s test: Failed to remount / private\n",
				   test_name);

	/* pid 1 in new pid namespace */
	pid1 = fork();
	if (pid1 < 0)
		ksft_exit_fail_msg("%s test: Failed to create new process\n",
				   test_name);

	if (pid1 == 0) {
		char buf[256];
		pid_t pid2;
		int pidfd = -1;

		(void)umount2("/proc", MNT_DETACH);
		ret = mount("proc", "/proc", "proc", 0, NULL);
		if (ret < 0)
			_exit(PIDFD_ERROR);

		/* grab pid PID_RECYCLE */
		for (i = 0; i <= PIDFD_MAX_DEFAULT; i++) {
			pid2 = fork();
			if (pid2 < 0)
				_exit(PIDFD_ERROR);

			if (pid2 == 0)
				_exit(PIDFD_PASS);

			if (pid2 == PID_RECYCLE) {
				snprintf(buf, sizeof(buf), "/proc/%d", pid2);
				ksft_print_msg("pid to recycle is %d\n", pid2);
				pidfd = open(buf, O_DIRECTORY | O_CLOEXEC);
			}

			if (wait_for_pid(pid2))
				_exit(PIDFD_ERROR);

			if (pid2 >= PID_RECYCLE)
				break;
		}

		/*
		 * We want to be as predictable as we can so if we haven't been
		 * able to grab pid PID_RECYCLE skip the test.
		 */
		if (pid2 != PID_RECYCLE) {
			/* skip test */
			close(pidfd);
			_exit(PIDFD_SKIP);
		}

		if (pidfd < 0)
			_exit(PIDFD_ERROR);

		for (i = 0; i <= PIDFD_MAX_DEFAULT; i++) {
			char c;
			int pipe_fds[2];
			pid_t recycled_pid;
			int child_ret = PIDFD_PASS;

			ret = pipe2(pipe_fds, O_CLOEXEC);
			if (ret < 0)
				_exit(PIDFD_ERROR);

			recycled_pid = fork();
			if (recycled_pid < 0)
				_exit(PIDFD_ERROR);

Annotation

Implementation Notes