demo_hook_async.c

/* libUIOHook: Cross-platform keyboard and mouse hooking from userland.
 * Copyright (C) 2006-2022 Alexander Barker.  All Rights Reserved.
 * https://github.com/kwhat/libuiohook/
 *
 * libUIOHook is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libUIOHook is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <inttypes.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <uiohook.h>
#include <wchar.h>

#ifdef _WIN32
#include <windows.h>
#else
#if defined(__APPLE__) && defined(__MACH__)
#include <CoreFoundation/CoreFoundation.h>
#endif

#include <pthread.h>
#endif

// Native thread errors.
#define UIOHOOK_ERROR_THREAD_CREATE 0x10

// Thread and mutex variables.
#ifdef _WIN32
static HANDLE hook_thread;

static CRITICAL_SECTION hook_running_mutex;
static CRITICAL_SECTION hook_control_mutex;
static CONDITION_VARIABLE hook_control_cond;
#else
static pthread_t hook_thread;

static pthread_mutex_t hook_running_mutex;
static pthread_mutex_t hook_control_mutex;
static pthread_cond_t hook_control_cond;
#endif


bool logger_proc(unsigned int level, const char *format, ...) {
    bool status = false;
    
    va_list args;
    switch (level) {
        case LOG_LEVEL_INFO:
            va_start(args, format);
            status = vfprintf(stdout, format, args) >= 0;
            va_end(args);
            break;

        case LOG_LEVEL_WARN:
        case LOG_LEVEL_ERROR:
            va_start(args, format);
            status = vfprintf(stderr, format, args) >= 0;
            va_end(args);
            break;
    }
    
    return status;
}

// NOTE: The following callback executes on the same thread that hook_run() is called 
// from.  This is important because hook_run() attaches to the operating systems
// event dispatcher and may delay event delivery to the target application.
// Furthermore, some operating systems may choose to disable your hook if it 
// takes too long to process.  If you need to do any extended processing, please 
// do so by copying the event to your own queued dispatch thread.
void dispatch_proc(uiohook_event * const event) {
    char buffer[256] = { 0 };
    size_t length = snprintf(buffer, sizeof(buffer), 
            "id=%i,when=%" PRIu64 ",mask=0x%X", 
            event->type, event->time, event->mask);
    
    switch (event->type) {
        case EVENT_HOOK_ENABLED:
            // Lock the running mutex so we know if the hook is enabled.
            #ifdef _WIN32
            EnterCriticalSection(&hook_running_mutex);
            #else
            pthread_mutex_lock(&hook_running_mutex);
            #endif
            
            // Unlock the control mutex so hook_enable() can continue.
            #ifdef _WIN32
            WakeConditionVariable(&hook_control_cond);
            LeaveCriticalSection(&hook_control_mutex);
            #else
            pthread_cond_signal(&hook_control_cond);
            pthread_mutex_unlock(&hook_control_mutex);
            #endif
            break;
            
        case EVENT_HOOK_DISABLED:
            // Lock the control mutex until we exit.
            #ifdef _WIN32
            EnterCriticalSection(&hook_control_mutex);
            #else
            pthread_mutex_lock(&hook_control_mutex);
            #endif
            
            // Unlock the running mutex so we know if the hook is disabled.
            #ifdef _WIN32
            LeaveCriticalSection(&hook_running_mutex);
            #else
            #if defined(__APPLE__) && defined(__MACH__)
            // Stop the main runloop so that this program ends.
            CFRunLoopStop(CFRunLoopGetMain());
            #endif
            
            pthread_mutex_unlock(&hook_running_mutex);
            #endif
            break;
        
        case EVENT_KEY_PRESSED:
            // If the escape key is pressed, naturally terminate the program.
            if (event->data.keyboard.keycode == VC_ESCAPE) {
                int status = hook_stop();
                switch (status) {
                    case UIOHOOK_SUCCESS:
                        // Everything is ok.
                        break;

                    // System level errors.
                    case UIOHOOK_ERROR_OUT_OF_MEMORY:
                        logger_proc(LOG_LEVEL_ERROR, "Failed to allocate memory. (%#X)", status);
                        break;
            
                    case UIOHOOK_ERROR_X_RECORD_GET_CONTEXT:
                        // NOTE This is the only platform specific error that occurs on hook_stop().
                        logger_proc(LOG_LEVEL_ERROR, "Failed to get XRecord context. (%#X)", status);
                        break;

                    // Default error.
                    case UIOHOOK_FAILURE:
                    default:
                        logger_proc(LOG_LEVEL_ERROR, "An unknown hook error occurred. (%#X)", status);
                        break;
                }
            }
        case EVENT_KEY_RELEASED:
            snprintf(buffer + length, sizeof(buffer) - length, 
                ",keycode=%u,rawcode=0x%X",
                event->data.keyboard.keycode, event->data.keyboard.rawcode);
            break;

        case EVENT_KEY_TYPED:
            snprintf(buffer + length, sizeof(buffer) - length, 
                ",keychar=%lc,rawcode=%u",
                (wint_t) event->data.keyboard.keychar,
                event->data.keyboard.rawcode);
            break;

        case EVENT_MOUSE_PRESSED:
        case EVENT_MOUSE_RELEASED:
        case EVENT_MOUSE_CLICKED:
        case EVENT_MOUSE_MOVED:
        case EVENT_MOUSE_DRAGGED:
            snprintf(buffer + length, sizeof(buffer) - length, 
                ",x=%i,y=%i,button=%i,clicks=%i",
                event->data.mouse.x, event->data.mouse.y,
                event->data.mouse.button, event->data.mouse.clicks);
            break;

        case EVENT_MOUSE_WHEEL:
            snprintf(buffer + length, sizeof(buffer) - length, 
                ",type=%i,amount=%i,rotation=%i",
                event->data.wheel.type, event->data.wheel.amount,
                event->data.wheel.rotation);
            break;

        default:
            break;
    }

    fprintf(stdout, "%s\n", buffer);
}

#ifdef _WIN32
DWORD WINAPI hook_thread_proc(LPVOID arg) {
#else
void *hook_thread_proc(void *arg) {
#endif
    // Set the hook status.
    int status = hook_run();
    if (status != UIOHOOK_SUCCESS) {
        #ifdef _WIN32
        *(DWORD *) arg = status;
        #else
        *(int *) arg = status;
        #endif
    }
    
    // Make sure we signal that we have passed any exception throwing code for
    // the waiting hook_enable().
    #ifdef _WIN32
    WakeConditionVariable(&hook_control_cond);
    LeaveCriticalSection(&hook_control_mutex);
    
    return status;
    #else
    // Make sure we signal that we have passed any exception throwing code for
    // the waiting hook_enable().
    pthread_cond_signal(&hook_control_cond);
    pthread_mutex_unlock(&hook_control_mutex);
    
    return arg;
    #endif
}

int hook_enable() {
    // Lock the thread control mutex.  This will be unlocked when the
    // thread has finished starting, or when it has fully stopped.
    #ifdef _WIN32
    EnterCriticalSection(&hook_control_mutex);
    #else
    pthread_mutex_lock(&hook_control_mutex);
    #endif
    
    // Set the initial status.
    int status = UIOHOOK_FAILURE;
    
    #ifndef _WIN32
    // Create the thread attribute.
    pthread_attr_t hook_thread_attr;
    pthread_attr_init(&hook_thread_attr);

    // Get the policy and priority for the thread attr.
    int policy;
    pthread_attr_getschedpolicy(&hook_thread_attr, &policy);
    int priority = sched_get_priority_max(policy);
    #endif
    
    #if defined(_WIN32)
    DWORD hook_thread_id;
    DWORD *hook_thread_status = malloc(sizeof(DWORD));
    hook_thread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) hook_thread_proc, hook_thread_status, 0, &hook_thread_id);
    if (hook_thread != INVALID_HANDLE_VALUE) {
    #else
    int *hook_thread_status = malloc(sizeof(int));
    if (pthread_create(&hook_thread, &hook_thread_attr, hook_thread_proc, hook_thread_status) == 0) {
    #endif
        #if defined(_WIN32)
        // Attempt to set the thread priority to time critical.
        if (SetThreadPriority(hook_thread, THREAD_PRIORITY_TIME_CRITICAL) == 0) {
            logger_proc(LOG_LEVEL_WARN, "%s [%u]: Could not set thread priority %li for thread %#p! (%#lX)\n",
                    __FUNCTION__, __LINE__, (long) THREAD_PRIORITY_TIME_CRITICAL,
                    hook_thread    , (unsigned long) GetLastError());
        }
        #elif (defined(__APPLE__) && defined(__MACH__)) || _POSIX_C_SOURCE >= 200112L || defined(__FreeBSD__)
        // Some POSIX revisions do not support pthread_setschedprio so we will 
        // use pthread_setschedparam instead.
        struct sched_param param = { .sched_priority = priority };
        if (pthread_setschedparam(hook_thread, SCHED_OTHER, &param) != 0) {
            logger_proc(LOG_LEVEL_WARN, "%s [%u]: Could not set thread priority %i for thread 0x%lX!\n",
                    __FUNCTION__, __LINE__, priority, (unsigned long) hook_thread);
        }
        #else
        // Raise the thread priority using glibc pthread_setschedprio.
        if (pthread_setschedprio(hook_thread, priority) != 0) {
            logger_proc(LOG_LEVEL_WARN, "%s [%u]: Could not set thread priority %i for thread 0x%lX!\n",
                    __FUNCTION__, __LINE__, priority, (unsigned long) hook_thread);
        }
        #endif
        
        
        // Wait for the thread to indicate that it has passed the 
        // initialization portion by blocking until either a EVENT_HOOK_ENABLED 
        // event is received or the thread terminates.
        // NOTE This unlocks the hook_control_mutex while we wait.
        #ifdef _WIN32
        SleepConditionVariableCS(&hook_control_cond, &hook_control_mutex, INFINITE);
        #else
        pthread_cond_wait(&hook_control_cond, &hook_control_mutex);
        #endif

        #ifdef _WIN32
        if (TryEnterCriticalSection(&hook_running_mutex) != FALSE) {
        #else
        if (pthread_mutex_trylock(&hook_running_mutex) == 0) {
        #endif
            // Lock Successful; The hook is not running but the hook_control_cond 
            // was signaled!  This indicates that there was a startup problem!
            
            // Get the status back from the thread.
            #ifdef _WIN32
            WaitForSingleObject(hook_thread,  INFINITE);
            GetExitCodeThread(hook_thread, hook_thread_status);
            #else
            pthread_join(hook_thread, (void **) &hook_thread_status);
            status = *hook_thread_status;
            #endif
        } else {
            // Lock Failure; The hook is currently running and wait was signaled
            // indicating that we have passed all possible start checks.  We can 
            // always assume a successful startup at this point.
            status = UIOHOOK_SUCCESS;
        }
        
        free(hook_thread_status);
    
        logger_proc(LOG_LEVEL_DEBUG, "%s [%u]: Thread Result: (%#X).\n",
                __FUNCTION__, __LINE__, status);
    }
    else {
        status = UIOHOOK_ERROR_THREAD_CREATE;
    }
    
    // Make sure the control mutex is unlocked.
    #ifdef _WIN32
    LeaveCriticalSection(&hook_control_mutex);
    #else
    pthread_mutex_unlock(&hook_control_mutex);
    #endif
    
    return status;
}


int main() {
    // Lock the thread control mutex.  This will be unlocked when the
    // thread has finished starting, or when it has fully stopped.
    #ifdef _WIN32
    // Create event handles for the thread hook.
    InitializeCriticalSection(&hook_running_mutex);
    InitializeCriticalSection(&hook_control_mutex);
    InitializeConditionVariable(&hook_control_cond);
    #else
    pthread_mutex_init(&hook_running_mutex, NULL);
    pthread_mutex_init(&hook_control_mutex, NULL);
    pthread_cond_init(&hook_control_cond, NULL);
    #endif
    
    // Set the logger callback for library output.
    hook_set_logger_proc(&logger_proc);
    
    // Set the event callback for uiohook events.
    hook_set_dispatch_proc(&dispatch_proc);

    // Start the hook and block.
    // NOTE If EVENT_HOOK_ENABLED was delivered, the status will always succeed.
    int status = hook_enable();
    switch (status) {
        case UIOHOOK_SUCCESS:
            // We no longer block, so we need to explicitly wait for the thread to die.
            #ifdef _WIN32
            WaitForSingleObject(hook_thread,  INFINITE);
            #else
            #if defined(__APPLE__) && defined(__MACH__)
            // NOTE Darwin requires that you start your own runloop from main.
            CFRunLoopRun();
            #endif
            
            pthread_join(hook_thread, NULL);
            #endif
            break;

        // System level errors.
        case UIOHOOK_ERROR_OUT_OF_MEMORY:
            logger_proc(LOG_LEVEL_ERROR, "Failed to allocate memory. (%#X)\n", status);
            break;


        // X11 specific errors.
        case UIOHOOK_ERROR_X_OPEN_DISPLAY:
            logger_proc(LOG_LEVEL_ERROR, "Failed to open X11 display. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_X_RECORD_NOT_FOUND:
            logger_proc(LOG_LEVEL_ERROR, "Unable to locate XRecord extension. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_X_RECORD_ALLOC_RANGE:
            logger_proc(LOG_LEVEL_ERROR, "Unable to allocate XRecord range. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_X_RECORD_CREATE_CONTEXT:
            logger_proc(LOG_LEVEL_ERROR, "Unable to allocate XRecord context. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_X_RECORD_ENABLE_CONTEXT:
            logger_proc(LOG_LEVEL_ERROR, "Failed to enable XRecord context. (%#X)\n", status);
            break;


        // Windows specific errors.
        case UIOHOOK_ERROR_SET_WINDOWS_HOOK_EX:
            logger_proc(LOG_LEVEL_ERROR, "Failed to register low level windows hook. (%#X)\n", status);
            break;


        // Darwin specific errors.
        case UIOHOOK_ERROR_AXAPI_DISABLED:
            logger_proc(LOG_LEVEL_ERROR, "Failed to enable access for assistive devices. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_CREATE_EVENT_PORT:
            logger_proc(LOG_LEVEL_ERROR, "Failed to create apple event port. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_CREATE_RUN_LOOP_SOURCE:
            logger_proc(LOG_LEVEL_ERROR, "Failed to create apple run loop source. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_GET_RUNLOOP:
            logger_proc(LOG_LEVEL_ERROR, "Failed to acquire apple run loop. (%#X)\n", status);
            break;

        case UIOHOOK_ERROR_CREATE_OBSERVER:
            logger_proc(LOG_LEVEL_ERROR, "Failed to create apple run loop observer. (%#X)\n", status);
            break;

        // Default error.
        case UIOHOOK_FAILURE:
        default:
            logger_proc(LOG_LEVEL_ERROR, "An unknown hook error occurred. (%#X)\n", status);
            break;
    }
    
    #ifdef _WIN32
    // Create event handles for the thread hook.
    CloseHandle(hook_thread);
    DeleteCriticalSection(&hook_running_mutex);
    DeleteCriticalSection(&hook_control_mutex);
    #else
    pthread_mutex_destroy(&hook_running_mutex);
    pthread_mutex_destroy(&hook_control_mutex);
    pthread_cond_destroy(&hook_control_cond); 
    #endif

    return status;
}