path: root/lldb/test/tools/lldb-gdbserver/main.cpp

#include <cstdlib>
#include <cstring>
#include <errno.h>
#include <inttypes.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <vector>

#if defined(__APPLE__)
__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_3_2)
int pthread_threadid_np(pthread_t,__uint64_t*);
#elif defined(__linux__)
#include <sys/syscall.h>
#endif

static const char *const RETVAL_PREFIX = "retval:";
static const char *const SLEEP_PREFIX  = "sleep:";
static const char *const STDERR_PREFIX = "stderr:";

static const char *const THREAD_PREFIX = "thread:";
static const char *const THREAD_COMMAND_NEW = "new"; 
static const char *const THREAD_COMMAND_PRINT_IDS = "print-ids"; 
static const char *const THREAD_COMMAND_SEGFAULT = "segfault"; 

static bool g_print_thread_ids = false;
static pthread_mutex_t g_print_mutex = PTHREAD_MUTEX_INITIALIZER;
static bool g_threads_do_segfault = false;

static pthread_mutex_t g_jump_buffer_mutex = PTHREAD_MUTEX_INITIALIZER;
static jmp_buf g_jump_buffer;
static bool g_is_segfaulting = false;

static void
print_thread_id ()
{
	// Put in the right magic here for your platform to spit out the thread id (tid) that debugserver/lldb-gdbserver would see as a TID.
	// Otherwise, let the else clause print out the unsupported text so that the unit test knows to skip verifying thread ids.
#if defined(__APPLE__)
	__uint64_t tid = 0;
	pthread_threadid_np(pthread_self(), &tid);
	printf ("%" PRIx64, tid);
#elif defined (__linux__)
	// This is a call to gettid() via syscall.
	printf ("%" PRIx64, static_cast<uint64_t> (syscall (__NR_gettid)));
#else
	printf("{no-tid-support}");
#endif
}

static void
signal_handler (int signo)
{
	const char *signal_name = NULL;
	switch (signo)
	{
		case SIGUSR1: signal_name = "SIGUSR1"; break;
		case SIGSEGV: signal_name = "SIGSEGV"; break;
		default:      signal_name = NULL;
	}

	// Print notice that we received the signal on a given thread.
	pthread_mutex_lock (&g_print_mutex);
	if (signal_name)
		printf ("received %s on thread id: ", signal_name);
	else
		printf ("received signo %d (%s) on thread id: ", signo, strsignal (signo));
	print_thread_id ();
	printf ("\n");
	pthread_mutex_unlock (&g_print_mutex);

	// Reset the signal handler if we're one of the expected signal handlers.
	switch (signo)
	{
	case SIGSEGV:
		// Fix up the pointer we're writing to.  This needs to happen if nothing intercepts the SIGSEGV
		// (i.e. if somebody runs this from the command line).
		longjmp(g_jump_buffer, 1);
		break;
	case SIGUSR1:
		if (g_is_segfaulting)
		{
			// Fix up the pointer we're writing to.  This is used to test gdb remote signal delivery.
			// A SIGSEGV will be raised when the thread is created, switched out for a SIGUSR1, and
			// then this code still needs to fix the seg fault.
			// (i.e. if somebody runs this from the command line).
			longjmp(g_jump_buffer, 1);
		}
		break;
	}

	// Reset the signal handler.
	sig_t sig_result = signal (signo, signal_handler);
	if (sig_result == SIG_ERR)
	{
		fprintf(stderr, "failed to set signal handler: errno=%d\n", errno);
		exit (1);
	}
}

static void*
thread_func (void *arg)
{
	static pthread_mutex_t s_thread_index_mutex = PTHREAD_MUTEX_INITIALIZER;
	static int s_thread_index = 1;

	pthread_mutex_lock (&s_thread_index_mutex);
	const int this_thread_index = s_thread_index++;
	pthread_mutex_unlock (&s_thread_index_mutex);

	if (g_print_thread_ids)
	{
		pthread_mutex_lock (&g_print_mutex);
		printf ("thread %d id: ", this_thread_index);
		print_thread_id ();
		printf ("\n");
		pthread_mutex_unlock (&g_print_mutex);
	}

	if (g_threads_do_segfault)
	{
		// Sleep for a number of seconds based on the thread index.
		// TODO add ability to send commands to test exe so we can
		// handle timing more precisely.  This is clunky.  All we're
		// trying to do is add predictability as to the timing of
		// signal generation by created threads.
		int sleep_seconds = 2 * (this_thread_index - 1);
		while (sleep_seconds > 0)
			sleep_seconds = sleep(sleep_seconds);
		
		// Test creating a SEGV.
		pthread_mutex_lock (&g_jump_buffer_mutex);
		g_is_segfaulting = true;
		int *bad_p = NULL;
		if (setjmp(g_jump_buffer) == 0)
		{
			// Force a seg fault signal on this thread.
			*bad_p = 0;
		}
		else
		{
			// Tell the system we're no longer seg faulting.
			// Used by the SIGUSR1 signal handler that we inject
			// in place of the SIGSEGV so it only tries to
			// recover from the SIGSEGV if this seg fault code
			// was in play.
			g_is_segfaulting = false;
		}
		pthread_mutex_unlock (&g_jump_buffer_mutex);

		pthread_mutex_lock (&g_print_mutex);
		printf ("thread ");
		print_thread_id ();
		printf (": past SIGSEGV\n");
		pthread_mutex_unlock (&g_print_mutex);
	}
	
	int sleep_seconds_remaining = 5;
	while (sleep_seconds_remaining > 0)
	{
		sleep_seconds_remaining = sleep (sleep_seconds_remaining);
	}

	return NULL;
}

int main (int argc, char **argv)
{
	std::vector<pthread_t> threads;
    int return_value = 0;

	// Set the signal handler.
	sig_t sig_result = signal (SIGALRM, signal_handler);
	if (sig_result == SIG_ERR)
	{
		fprintf(stderr, "failed to set SIGALRM signal handler: errno=%d\n", errno);
		exit (1);
	}

	sig_result = signal (SIGUSR1, signal_handler);
	if (sig_result == SIG_ERR)
	{
		fprintf(stderr, "failed to set SIGUSR1 handler: errno=%d\n", errno);
		exit (1);
	}

	sig_result = signal (SIGSEGV, signal_handler);
	if (sig_result == SIG_ERR)
	{
		fprintf(stderr, "failed to set SIGUSR1 handler: errno=%d\n", errno);
		exit (1);
	}
	
	// Process command line args.
    for (int i = 1; i < argc; ++i)
    {
        if (std::strstr (argv[i], STDERR_PREFIX))
        {
            // Treat remainder as text to go to stderr.
            fprintf (stderr, "%s\n", (argv[i] + strlen (STDERR_PREFIX)));
        }
        else if (std::strstr (argv[i], RETVAL_PREFIX))
        {
            // Treat as the return value for the program.
            return_value = std::atoi (argv[i] + strlen (RETVAL_PREFIX));
        }
        else if (std::strstr (argv[i], SLEEP_PREFIX))
        {
            // Treat as the amount of time to have this process sleep (in seconds).
            int sleep_seconds_remaining = std::atoi (argv[i] + strlen (SLEEP_PREFIX));
			
			// Loop around, sleeping until all sleep time is used up.  Note that
			// signals will cause sleep to end early with the number of seconds remaining.
			for (int i = 0; sleep_seconds_remaining > 0; ++i)
			{
				sleep_seconds_remaining = sleep (sleep_seconds_remaining);
				// std::cout << "sleep result (call " << i << "): " << sleep_seconds_remaining << std::endl;
			}
        }
		else if (std::strstr (argv[i], THREAD_PREFIX))
		{
			// Check if we're creating a new thread.
			if (std::strstr (argv[i] + strlen(THREAD_PREFIX), THREAD_COMMAND_NEW))
			{
				// Create a new thread.
				pthread_t new_thread;
				const int err = ::pthread_create (&new_thread, NULL, thread_func, NULL);
			    if (err)
				{
					fprintf (stderr, "pthread_create() failed with error code %d\n", err);
					exit (err);
				}
				threads.push_back (new_thread);
			}
			else if (std::strstr (argv[i] + strlen(THREAD_PREFIX), THREAD_COMMAND_PRINT_IDS))
			{
				// Turn on thread id announcing.
				g_print_thread_ids = true;
				
				// And announce us.
				pthread_mutex_lock (&g_print_mutex);
				printf ("thread 0 id: ");
				print_thread_id ();
				printf ("\n");
				pthread_mutex_unlock (&g_print_mutex);
			}
			else if (std::strstr (argv[i] + strlen(THREAD_PREFIX), THREAD_COMMAND_SEGFAULT))
			{
				g_threads_do_segfault = true;
			}
			else
			{
				// At this point we don't do anything else with threads.
				// Later use thread index and send command to thread.
			}
		}
        else
        {
            // Treat the argument as text for stdout.
            printf("%s\n", argv[i]);
        }
    }

	// If we launched any threads, join them
	for (std::vector<pthread_t>::iterator it = threads.begin (); it != threads.end (); ++it)
	{
		void *thread_retval = NULL;
		const int err = ::pthread_join (*it, &thread_retval);
	    if (err != 0)
			fprintf (stderr, "pthread_join() failed with error code %d\n", err);
	}

    return return_value;
}