下面是 button.c
#include <gtk/gtk.h> static void close_window (void) { gtk_main_quit (); } static void print_msg (GtkWidget *button , gpointer data) { printf("Hello , world!\n"); } static void activate (GtkApplication *app , gpointer data) { GtkWidget *win; //申明一个按钮 GtkWidget *button; //申明一个盒容器,用于容纳按钮,控制大小 GtkWidget *button_box; win = gtk_application_window_new(app); gtk_window_set_title(GTK_WINDOW(win) , "Button test"); gtk_window_set_default_size(GTK_WINDOW(win) , 200 , 200); g_signal_connect (win, "destroy", G_CALLBACK (close_window), NULL); //创建一个盒容器,并设置水平放置 button_box = gtk_button_box_new(GTK_ORIENTATION_HORIZONTAL); //gtk_orientation_horizontal //将盒容器包含进window中 gtk_container_add(GTK_CONTAINER(win) , button_box); button = gtk_button_new_with_label("My button"); g_signal_connect (button ,"clicked", G_CALLBACK (print_msg), NULL); gtk_container_add(GTK_CONTAINER(button_box), button); //显示window及其所有控件 gtk_widget_show_all(win); } int main(int argc , char **argv) { GtkApplication *app; int app_status; app = gtk_application_new("org.gtk.exmple" , G_APPLICATION_FLAGS_NONE); g_signal_connect(app , "activate" , G_CALLBACK(activate) , NULL); app_status = g_application_run(G_APPLICATION(app) , argc , argv); g_object_unref(app); return app_status; }
下面是hook.c
#include <dlfcn.h> #include<gtk/gtk.h> void func() { printf("NO! I don't want to see you\n"); } /*#define g_signal_connect(instance, detailed_signal, c_handler, data) \ g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0) */ typedef gulong (*SIGNAL)(gpointer instance, const gchar *detailed_signal,GCallback c_handler, gpointer data ,GClosureNotify destroy_data,GConnectFlags connect_flags); gulong g_signal_connect_data (gpointer instance, const gchar *detailed_signal,GCallback c_handler, gpointer data,GClosureNotify destroy_data,GConnectFlags connect_flags) { static void *handle = NULL; static SIGNAL old_connect = NULL; if(!handle) { handle = dlopen("libgtk-3.so.0", RTLD_LAZY); old_connect = (SIGNAL)dlsym(handle, "g_signal_connect_data"); } if(0 == strcmp("clicked", detailed_signal)) { return old_connect(instance, detailed_signal, func, data, destroy_data, connect_flags); } return old_connect(instance, detailed_signal, c_handler, data, destroy_data, connect_flags); }
button.c要实现的是点击按钮实现屏幕打印hello word!
我hook住g_signal_connect()函数,把回调函数改成我自己的函数。
gcc button.c -o button `pkg-config --cflags --libs gtk+-3.0`
gcc -fPIC -shared -o hook.so hook.c -ldl `pkg-config --cflags --libs gtk+-3.0`
LD_PRELOAD=$PWD/hook.so button
就可以看到效果了