Small wrapper to troubleshoot libMali issues

wrapper.c

// Compile: gcc -ldl wrapper.c -g -shared -o libwrapper.so
// Usage: LD_PRELOAD="./libwrapper.so" {program}

#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
#include <string.h>

#include <EGL/egl.h>
#include <X11/Xutil.h>

typedef struct wrapper_s {
    char initialized;
    void* libMali;
    void* libX;
    EGLDisplay (*eglGetDisplay)(EGLNativeDisplayType);
    XVisualInfo* (*XGetVisualInfo)(Display*, long, XVisualInfo*, int*);
    Display* (*XOpenDisplay)(const char*);
} wrapper;

static wrapper wrapper_g;

void wrapper_load()
{
    if(wrapper_g.initialized)
	return;

    printf("WRAPPER: [LOADED]\n");

    char *error;
    wrapper_g.initialized = 1;

    // Load libMali
    wrapper_g.libMali = dlopen("libMali.so", RTLD_LAZY);
    wrapper_g.libX = dlopen("libX11.so", RTLD_LAZY);

    if (!wrapper_g.libMali) {
	fprintf (stderr, "%s\n", dlerror());
	exit(1);
    }
    dlerror();    /* Clear any existing error */

    // Load symbols
    wrapper_g.eglGetDisplay = dlsym(wrapper_g.libMali, "eglGetDisplay");
    wrapper_g.XGetVisualInfo = dlsym(wrapper_g.libX, "XGetVisualInfo");
    wrapper_g.XOpenDisplay = dlsym(wrapper_g.libX, "XOpenDisplay");

    // Check if any error happened
    if ((error = dlerror()) != NULL)  {
	fprintf (stderr, "%s\n", error);
	exit(1);
    }
}

EGLDisplay eglGetDisplay (EGLNativeDisplayType display_id)
{
    wrapper_load();

    printf("WRAPPER: eglGetDisplay (param) display_id: %p\n", (void*) display_id);

    EGLDisplay out = (*(wrapper_g.eglGetDisplay))(EGL_DEFAULT_DISPLAY);

    printf("WRAPPER: eglGetDisplay return: %p\n", (void*) out);

    return out;

}

Display* XOpenDisplay(const char* display){
    wrapper_load();

    printf("WRAPPER: XOpenDisplay (param) display: %p\n", (void*) display);

    Display* out = (*(wrapper_g.XOpenDisplay))(display);

    printf("WRAPPER: XOpenDisplay return: %p\n", (void*) out);

    return out;
}

XVisualInfo* XGetVisualInfo(
    Display* display,
    long vinfo_mask,
    XVisualInfo* vinfo_template,
    int*   nitems_return
)
{
    printf("WRAPPER: XGetVisualInfo (param) display: %p\n", (void*) display);
    printf("WRAPPER: XGetVisualInfo (param) vinfo_mask: %ld\n", vinfo_mask);
    printf("WRAPPER: XGetVisualInfo (param) vinfo_template.visualid %ld\n", vinfo_template->visualid);

    XVisualInfo* out = (*(wrapper_g.XGetVisualInfo))(
	display,
	vinfo_mask,
	vinfo_template,
	nitems_return
    );

    printf("WRAPPER: XGetVisualInfo return: %p\n", (void*) out);

    return out;
}