/*
 * Copyright (c) 2023 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 * These tests verify that proc_pidinfo returns the expected exit reason and
 * namespace for signal-related process termination.
 */

#include <darwintest.h>
#include <signal.h>
#include <libproc.h>
#include <sys/wait.h>
#include <sys/reason.h>
#include <stdlib.h>
#include <dispatch/dispatch.h>
#include <unistd.h>
#include <mach/kern_return.h>
#include <mach/mach.h>
#include <mach/mach_port.h>
#include <mach/message.h>
#include <mach/port.h>


T_GLOBAL_META(
	T_META_TAG_VM_PREFERRED,
	T_META_NAMESPACE("xnu.misc"),
	T_META_RADAR_COMPONENT_NAME("xnu"),
	T_META_RADAR_COMPONENT_VERSION("signals"),
	T_META_CHECK_LEAKS(false),
	T_META_RUN_CONCURRENTLY(true));

static dispatch_queue_t exit_queue;

static void
cleanup(void)
{
	dispatch_release(exit_queue);
}

static void
dispatch_test(void (^test)(void))
{
	// Use dispatch to schedule DISPATCH_PROC_EXIT blocks to read out exit reasons
	exit_queue = dispatch_queue_create("exit queue", DISPATCH_QUEUE_SERIAL);
	dispatch_async(dispatch_get_main_queue(), ^{
		test();
	});
	T_ATEND(cleanup);
	dispatch_main();
}

static bool
audit_token_for_pid(pid_t pid, audit_token_t *token)
{
	kern_return_t err;
	task_name_t task_name = TASK_NAME_NULL;
	mach_msg_type_number_t info_size = TASK_AUDIT_TOKEN_COUNT;

	err = task_name_for_pid(mach_task_self(), pid, &task_name);
	if (err != KERN_SUCCESS) {
		T_LOG("task_for_pid returned %d\n", err);
		return false;
	}

	err = task_info(task_name, TASK_AUDIT_TOKEN, (integer_t *)token, &info_size);
	if (err != KERN_SUCCESS) {
		T_LOG("task_info returned %d\n", err);
		return false;
	}

	return true;
}

static void
check_exit_reason(int pid, uint64_t expected_reason_namespace, uint64_t expected_signal)
{
	T_LOG("check_exit_reason %d", expected_signal);
	int ret, status;
	struct proc_exitreasonbasicinfo exit_reason;

	ret = proc_pidinfo(pid, PROC_PIDEXITREASONBASICINFO, 1, &exit_reason, PROC_PIDEXITREASONBASICINFOSIZE);
	T_WITH_ERRNO; T_QUIET; T_ASSERT_EQ(ret, PROC_PIDEXITREASONBASICINFOSIZE, "retrieve basic exit reason info");

	waitpid(pid, &status, 0);
	T_QUIET; T_EXPECT_FALSE(WIFEXITED(status), "process did not exit normally");
	T_QUIET; T_EXPECT_TRUE(WIFSIGNALED(status), "process was terminated because of a signal");
	T_QUIET; T_EXPECT_EQ(WTERMSIG(status), expected_signal, "process should terminate due to signal %llu", expected_signal);

	T_EXPECT_EQ(exit_reason.beri_namespace, expected_reason_namespace, "expect OS_REASON_SIGNAL");
	T_EXPECT_EQ(exit_reason.beri_code, expected_signal, "expect reason code: %llu", expected_signal);
}

static void
wait_collect_exit_reason(int pid, int signal)
{
	dispatch_source_t ds_proc = dispatch_source_create(DISPATCH_SOURCE_TYPE_PROC, pid, DISPATCH_PROC_EXIT, exit_queue);
	dispatch_semaphore_t sem = dispatch_semaphore_create(0);
	dispatch_source_set_event_handler(ds_proc, ^{
		check_exit_reason(pid, OS_REASON_SIGNAL, signal);
		dispatch_semaphore_signal(sem);
	});
	dispatch_activate(ds_proc);

	// Wait till exit reason is processed
	dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
	dispatch_release(ds_proc);
	dispatch_release(sem);
}

static void
wait_with_timeout_expected(int pid, int seconds)
{
	long timeout = 0;
	dispatch_source_t ds_proc = dispatch_source_create(DISPATCH_SOURCE_TYPE_PROC, pid, DISPATCH_PROC_EXIT, exit_queue);
	dispatch_semaphore_t sem = dispatch_semaphore_create(0);
	dispatch_time_t milestone = dispatch_time(DISPATCH_TIME_NOW, seconds * NSEC_PER_SEC);;
	dispatch_source_set_event_handler(ds_proc, ^{
		dispatch_semaphore_signal(sem);
	});
	dispatch_activate(ds_proc);

	// Wait till exit reason is processed or timeout
	timeout = dispatch_semaphore_wait(sem, milestone);
	T_QUIET; T_EXPECT_TRUE(timeout != 0, "process exited and was not expected to");
	dispatch_release(ds_proc);
	dispatch_release(sem);
}

static void
__test_exit_reason_abort()
{
	pid_t child = fork();
	if (child > 0) {
		wait_collect_exit_reason(child, SIGABRT);
	} else {
		abort();
	}
}

T_DECL(test_exit_reason_abort, "tests exit reason for abort()", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_abort();
		T_END;
	});
}

static void
__test_exit_reason_external_signal(int signal)
{
	T_LOG("Testing external signal %d", signal);
	pid_t child = fork();
	if (child > 0) {
		// Send external signal
		kill(child, signal);
		wait_collect_exit_reason(child, signal);
	} else {
		pause();
	}
}

static void
__test_exit_reason_delegate_signal(int signal)
{
	int ret = 0;
	audit_token_t instigator = INVALID_AUDIT_TOKEN_VALUE;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;
	pid_t child = fork();
	if (child > 0) {
		audit_token_for_pid(getpid(), &instigator);
		audit_token_for_pid(child, &token);
		// Send signal to the child with its audit token
		ret = proc_signal_delegate(instigator, token, signal);
		T_EXPECT_EQ_INT(ret, 0, "expect proc_signal_delegate return: %d", ret);
		wait_collect_exit_reason(child, signal);
		// Send signal to the child with its audit token who has exited by now
		ret = proc_signal_delegate(instigator, token, signal);
		T_EXPECT_EQ_INT(ret, ESRCH, "expect no such process return: %d", ret);
	} else {
		pause();
		// This exit should not hit, but we exit abnormally in case something went wrong
		_exit(-1);
	}
}

static void
__test_exit_reason_delegate_terminate()
{
	int ret = 0;
	audit_token_t instigator = INVALID_AUDIT_TOKEN_VALUE;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;
	pid_t child = fork();
	int sentsignal = 0;
	if (child > 0) {
		audit_token_for_pid(getpid(), &instigator);
		audit_token_for_pid(child, &token);
		// Send signal to the child with its audit token
		ret = proc_terminate_delegate(instigator, token, &sentsignal);
		T_EXPECT_EQ_INT(ret, 0, "expect proc_terminate_delegate return: %d", ret);
		T_EXPECT_TRUE(sentsignal == SIGTERM || sentsignal == SIGKILL, "sentsignal retval %d", sentsignal);
		wait_collect_exit_reason(child, SIGTERM);
		// Send signal to the child with its audit token who has exited by now
		ret = proc_terminate_delegate(instigator, token, &sentsignal);
		T_EXPECT_EQ_INT(ret, ESRCH, "expect no such process return: %d", ret);
		// Terminating PID 1 should fail with EPERM
		if (audit_token_for_pid(1, &token)) {
			ret = proc_terminate_delegate(instigator, token, &sentsignal);
			T_EXPECT_EQ_INT(ret, EPERM, "expected eperm return: %d", ret);
		}
	} else {
		pause();
		// This exit should not hit, but we exit abnormally in case something went wrong
		_exit(-1);
	}
}

static void
__test_exit_reason_terminate()
{
	int ret = 0;
	pid_t child = fork();
	int sentsignal = 0;
	if (child > 0) {
		// Send signal to the child with its audit token
		ret = proc_terminate(child, &sentsignal);
		T_EXPECT_EQ_INT(ret, 0, "expect proc_terminate_delegate return: %d", ret);
		T_EXPECT_TRUE(sentsignal == SIGTERM || sentsignal == SIGKILL, "sentsignal retval %d", sentsignal);
		wait_collect_exit_reason(child, SIGTERM);
		// Send signal to the child with its audit token who has exited by now
		ret = proc_terminate(child, &sentsignal);
		T_EXPECT_EQ_INT(ret, ESRCH, "expected no such process return: %d", ret);
		// Terminating PID 1 should fail with EPERM
		ret = proc_terminate(1, &sentsignal);
		T_EXPECT_EQ_INT(ret, EPERM, "expected eperm return: %d", ret);
	} else {
		pause();
		// This exit should not hit, but we exit abnormally in case something went wrong
		_exit(-1);
	}
}

static void
__test_exit_reason_signal_with_audittoken(int signal)
{
	int ret = 0;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;
	pid_t child = fork();
	if (child > 0) {
		audit_token_for_pid(child, &token);
		// Send signal to the child with its audit token
		ret = proc_signal_with_audittoken(&token, signal);
		wait_collect_exit_reason(child, signal);
		T_EXPECT_EQ_INT(ret, 0, "expect proc_signal_with_audittoken return: %d", ret);
		// Send signal to the child with its audit token who has exited by now
		ret = proc_signal_with_audittoken(&token, signal);
		T_EXPECT_EQ_INT(ret, ESRCH, "expect no such process return: %d", ret);
	} else {
		pause();
		// This exit should not hit, but we exit abnormally in case something went wrong
		_exit(-1);
	}
}

static void
__test_exit_reason_signal_with_audittoken_fail_bad_token(int signal)
{
	int ret = 0;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;
	pid_t child = fork();
	if (child > 0) {
		audit_token_for_pid(child, &token);
		// Send signal to the child with its audit token, modified so pidversion is bad
		token.val[7] += 1;
		ret = proc_signal_with_audittoken(&token, signal);
		wait_with_timeout_expected(child, 2);
		T_EXPECT_EQ_INT(ret, ESRCH, "expect bad audit token return: %d", ret);
		// Cleanup child
		kill(child, signal);
	} else {
		pause();
	}
}

static void
__test_exit_reason_delegated_signal_fail_bad_instigator_token(int signal)
{
	int ret = 0;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;
	audit_token_t instigator = INVALID_AUDIT_TOKEN_VALUE;
	pid_t child = fork();
	if (child > 0) {
		audit_token_for_pid(child, &token);
		ret = proc_signal_delegate(instigator, token, signal);
		wait_with_timeout_expected(child, 2);
		T_EXPECT_EQ_INT(ret, ESRCH, "expect bad audit token return: %d", ret);
		// Cleanup child
		kill(child, signal);
	} else {
		pause();
	}
}

static void
__test_exit_reason_signal_with_audittoken_fail_null_token(int signal)
{
	int ret = 0;
	pid_t child = fork();
	if (child > 0) {
		// Send signal to the child with null audit token
		ret = proc_signal_with_audittoken(NULL, signal);
		wait_with_timeout_expected(child, 2);
		T_EXPECT_EQ_INT(ret, EINVAL, "expect null audit token return: %d", ret);
		// Cleanup child
		kill(child, signal);
	} else {
		pause();
	}
}

static void
__test_exit_reason_signal_with_audittoken_fail_bad_signal(int signal)
{
	int ret = 0;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;
	pid_t child = fork();
	if (child > 0) {
		audit_token_for_pid(child, &token);
		ret = proc_signal_with_audittoken(&token, signal);
		wait_with_timeout_expected(child, 2);
		T_EXPECT_EQ_INT(ret, EINVAL, "expect invalid sig num return: %d", ret);
		kill(child, signal);
	} else {
		pause();
	}
}

// Required signal handler for sigwait to work properly
static void
null_signal_handler(int sig)
{
}

static void
__test_signal_zombie(void)
{
	pid_t child;
	sigset_t set;
	sigset_t oldset;
	int sig = 0, ret = 0;
	audit_token_t token = INVALID_AUDIT_TOKEN_VALUE;

	// Set signal handler
	signal(SIGCHLD, &null_signal_handler);

	// Mask SIGCHLD so it becomes pending
	// when the child dies.
	sigemptyset(&set);
	sigaddset(&set, SIGCHLD);
	sigprocmask(SIG_BLOCK, &set, &oldset);

	// Immediately exit child
	if ((child = fork()) == 0) {
		sleep(1);
		exit(0);
	}

	// Calculate target audit token
	T_EXPECT_TRUE(audit_token_for_pid(child, &token), "audit token determined");

	// Wait for kernel to notify us of a dead child. Which means it's now in a
	// zombie state.
	sigwait(&set, &sig);

	// Restore process mask
	sigprocmask(SIG_SETMASK, &oldset, NULL);

	// First test that kill succeeds for POSIX compliance
	T_EXPECT_EQ_INT(kill(child, 0), 0, "kill() suceeds on a zombie");

	// Then test that the proc_info path has a sensible error code
	ret = proc_signal_with_audittoken(&token, SIGHUP);
	T_EXPECT_EQ_INT(ret, ESRCH, "expect invalid sig num return: %d", ret);

	// Cleanup zombie child
	wait_with_timeout_expected(child, 0);
}


T_DECL(signal_zombie, "signaling a zombie should work", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_signal_zombie();
		T_END;
	});
}

T_DECL(proc_signal_delegate_success, "proc_signal_delegate should work", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_delegate_signal(SIGABRT);
		__test_exit_reason_delegate_signal(SIGKILL);
		__test_exit_reason_delegate_signal(SIGSYS);
		__test_exit_reason_delegate_signal(SIGUSR1);
		__test_exit_reason_delegate_terminate();
		T_END;
	});
}

T_DECL(proc_terminate_success, "proc_terminate should work", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_terminate();
		T_END;
	});
}

T_DECL(proc_signal_with_audittoken_success, "proc_signal_with_audittoken should work", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_signal_with_audittoken(SIGABRT);
		__test_exit_reason_signal_with_audittoken(SIGKILL);
		__test_exit_reason_signal_with_audittoken(SIGSYS);
		__test_exit_reason_signal_with_audittoken(SIGUSR1);
		T_END;
	});
}

T_DECL(proc_signal_with_audittoken_fail_bad_token, "proc_signal_with_audittoken should fail with invalid audit token", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_signal_with_audittoken_fail_bad_token(SIGKILL);
		T_END;
	});
}

T_DECL(proc_delegated_signal_fail_bad_instigator_token, "proc_signal_delegated should fail with invalid instigator audit token", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_delegated_signal_fail_bad_instigator_token(SIGKILL);
		T_END;
	});
}

T_DECL(proc_signal_with_audittoken_fail_null_token, "proc_signal_with_audittoken should fail with a null audit token", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_signal_with_audittoken_fail_null_token(SIGKILL);
		T_END;
	});
}

T_DECL(proc_signal_with_audittoken_fail_bad_signal, "proc_signal_with_audittoken should fail with invalid signals", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_signal_with_audittoken_fail_bad_signal(0);
		__test_exit_reason_signal_with_audittoken_fail_bad_signal(NSIG + 1);
		T_END;
	});
}

T_DECL(test_exit_reason_external_signal, "tests exit reason for external signals", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_external_signal(SIGABRT);
		__test_exit_reason_external_signal(SIGKILL);
		__test_exit_reason_external_signal(SIGSYS);
		__test_exit_reason_external_signal(SIGUSR1);
		T_END;
	});
}

struct pthread_kill_helper_args {
	pthread_t *pthread;
	int signal;
};

static void *_Nullable
pthread_kill_helper(void *_Nullable msg)
{
	struct pthread_kill_helper_args *args = (struct pthread_kill_helper_args *)msg;
	pthread_kill(*args->pthread, args->signal);
	return NULL;
}

static void
__test_exit_reason_pthread_kill_self(int signal)
{
	T_LOG("Testing pthread_kill for signal %d", signal);
	pid_t child = fork();
	if (child > 0) {
		wait_collect_exit_reason(child, signal);
	} else {
		pthread_t t;
		struct pthread_kill_helper_args args = {&t, signal};
		pthread_create(&t, NULL, (void*(*)(void*))pthread_kill_helper, (void *)&args);
		pthread_join(t, NULL);
	}
}

T_DECL(test_exit_reason_pthread_kill_self, "tests exit reason for pthread_kill on caller thread", T_META_TAG_VM_PREFERRED)
{
	dispatch_test(^{
		__test_exit_reason_pthread_kill_self(SIGABRT);
		__test_exit_reason_pthread_kill_self(SIGKILL);
		__test_exit_reason_pthread_kill_self(SIGSYS);
		__test_exit_reason_pthread_kill_self(SIGUSR1);
		T_END;
	});
}